Background: In recent times, last mile deliveries have become critical as these deliveries are generally considered to be the most expensive, least efficient and most polluted part of the entire logistics chain (De Kervenoael, Schwob & Chandra 2020; McKinnon & Edwards 2009). Consumer demands for fast and flexible deliveries are not very easy to combine with the highest possible sustainability focus (PostNord 2018). By informing about different transport alternatives and vehicle types, the consumer gets the opportunity to influence their own environmental impact when making a purchase (Buldeo Rai, Verlinde & Macharis 2019). Despite the fact that companies today have better possibilities to share data about their environmental practices with the end customer, there is still a lack of such information on the website. Few companies adopt effective web-based communications that inform their stakeholders about their sustainable behaviors (Da Giau, Macchion, Caniato, Caridi, Danese, Rinaldi & Vinelli 2016).  Theory: A theoretical research model “Green web communication” has been developed based on the theories 3’C and OSEC. The theory ten signs of greenwash has also been applied to identify signs of greenwash.  Purpose and research question: The purpose of the study is to map out various alternatives for green marketing within the last mile, to increase the understanding of how ecommerce companies can influence consumers to a more conscious delivery choice. Furthermore, the paper aims to study how the web communication should be developed to avoid greenwashing. In order to answer the purpose, the following research questions have been formulated: How do e-commerce companies communicate green deliveries on the website? In what way can green web communication show signs of greenwashing? How is web communication presented in relation to what is expressed internally?  Methodology: To answer the research question a qualitative method was conducted with a constructivism approach. First a qualitative content analysis was performed on the website of sixteen e-commerce companies, divided into four different industries. The second method involved three semi-structured interviews with representatives of the selected companies Skincity, CDON and Ellos.  Conclusion: Communication about green deliveries appeared frequently at the e-commerce companies’ check-out compared with the information page, home page and group’s website. The representation of green commitments appeared in varying degrees in the form of eco-labels, symbols or information text. Furthermore, the green sustainability commitments were expressed in different ways where the content could be found in various green statements: climate compensation, CO2 emissions or green policy. The web communication also showed that transparency was lacking in far too many aspects as the communication could be identified as greenwashing in several cases. Greenwashing was identified when analyzing the green web communication in aspects of no proof and fluffy language. The internal communication from representatives of the e-commerce companies differed from the communication on the websites. This indicates a discrepancy between the internal and the external communication which neglects the e-companies sustainability commitments. / Bakgrund: På senare tid har last mile leveranser blivit ett kritiskt område då leveranserna iallmänhet anses vara de dyraste, minst effektiva och mest förorenade delen i hela logistikkedjan(De Kervenoael, Schwob & Chandra 2020; McKinnon & Edwards 2009). Konsumentens kravpå snabba och flexibla leveranser är inte särskilt enkla att förena med högsta möjligahållbarhetsfokus (PostNord 2018). Genom att informera om olika transportalternativ ochfordonstyper får konsumenten möjlighet att påverka sin egna miljöpåverkan vid ett köp (BuldeoRai, Verlinde & Macharis 2019). Trots det faktum att företag har större möjligheter att deladata om sin miljömässiga praxis med slutkunden finns de fortfarande en brist av sådaninformation på webbplatsen. Få företag antar effektiv webbaserad kommunikation sominformerar sina intressenter om deras hållbara beteenden (Da Giau, Macchion, Caniato, Caridi,Danese, Rinaldi & Vinelli 2016).  Teori: En teoretisk undersökningsmodell “Grön webbkommunikation” har utvecklats baseratpå teorierna 3’C och OSEC. Teorin ten signs of greenwash har vidare tillämpats för attidentifiera tecken på greenwash.  Syfte och forskningsfråga: Syftet med studien är att kartlägga olika alternativ för grönmarknadsföring av last mile, samt att bidra med en ökad förståelse kring hur e-handelsföretagenkan påverka konsumenten till ett medvetet leveransval. Vidare ska även studien beröra hurkommunikationen på webbplatsen bör utformas för att undvika greenwashing. För att besvarasyftet har följande forskningsfrågor utformats: Hur kommunicerar företag gröna leveranser påwebbplatsen? På vilket sätt kan den gröna webbkommunikationen visa tecken pågreenwashing? Hur framställs webbkommunikationen gentemot resonemang som uttrycksinternt?  Metod: Denna studie genomfördes med en kvalitativ metod som är av konstruktivistiskkaraktär. Först utfördes en kvalitativ innehållsanalys på webbplatsen av sexton e-handelsföretagsom delades in i fyra olika branscher. Den andra metoden innefattar tre semistruktureradeintervjuer med företrädare från de utvalda företagen Skincity, CDON och Ellos.  Slutsats: Kommunikation om gröna leveranser framkom frekvent på e-handelsaktörernascheck-out jämfört med webbplatsens informationssida, startsida samt koncernens webbplats.Framställningen av gröna åtaganden förekom i miljömärkning, symbol eller informationstext ivarierande grad. Vidare uttrycktes de gröna hållbarhetsåtaganden på olika sätt där innehålletgick att härleda till olika gröna påståenden: klimatkompensera, CO2-utsläpp eller grön policy.Webbkommunikationen uppvisade en låg grad av transparens och flertalet brister i allt förmånga avseenden då man ofta kunde härleda kommunikationen till greenwashing.Greenwashing identifierades vid granskning av fallförtagens gröna kommunikation som gickatt härleda till no proof och fluffy language. Den interna kommunikationen skiljer sig mot denkommunikation som fanns att tillgå webbplatsen. Det råder således en diskrepans mellan deninterna och externa kommunikationen vilket försummar aktörens hållbarhetåtaganden.

Orientador: Fernando Lucas Primo / Resumo: O avanço tecnológico cresce rapidamente no mundo, inclusive na área farmacêutica. Nesse contexto, sistemas nanoestruturados ganham progressivo destaque, porquanto carregam um enorme potencial para o aperfeiçoamento das práticas terapêuticas atuais. A administração de fármacos na forma livre pode apresentar problemas como baixa concentração no sítio ativo, inadequada distribuição pelo organismo, baixa biodisponibilidade, presença de efeitos adversos, entre outros. As nanocápsulas poliméricas são capazes de contornar tais vieses, possibilitando, inclusive, a diminuição da toxicidade com a diminuição de doses e aumento da estabilidade de fármacos em meios biológicos. Foram desenvolvidas nanocápsulas poliméricas contendo Anfotericina B (AMB) e Fenil-tio-ftalocianina de zinco (ZnS4Pc) na concentração teórica de 0,05 mg.mL-1 objetivando, com a associação entre os dois ativos, melhorar a atividade antifúngica conseguida pelo antifúngico isoladamente utilizando-se a Terapia Fotodinâmica Antimicrobiana. A avaliação das características físico-químicas das nanocápsulas mostraram diâmetro médio de partícula de 253,8 ± 17,3 nm, índice de polidispersidade médio de 0,36 ± 0,01 e potencial Zeta médio de – 31,03 ± 5,54 mV. Tais análises revelaram-se satisfatórias já que o diâmetro de partícula conseguido pelo método de deposição interfacial de polímero pré-formado utilizado na produção das nanocápsulas varia de 250 a 500 nm (MORA-HUERTAS et. al., 2010), enquanto que o potencial zeta considera... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Technological advancement is growing rapidly in the world, including the pharmaceutical area. In this context, nanostructured systems gains progressive prominence, as they carry enormous potential for the improvement of current therapeutic practices. The drugs administration in the free-form may present problems such as low active site concentration, inadequate distribution throughout body, low bioavailability, presence of adverse effects, among others. Polymeric nanocapsules allowing the reduction of toxicity with decreasing doses and increasing the stability of drugs in biologic media. Polymeric nanocapsules containing Amphotericin B (AMB) and zinc phenyl-thio-phthalocyanine (ZnS4Pc) were developed at a 0.05 mg/mL theoretical concentration to improve antifungal activity with the association between the two actives over antifungal alone. The nanocapsules physical-chemical characteristics showed an average particle diameter of 253,8 ± 17,3 nm, an average polydispersity index of 0,36 ± 0,01 and negative Zeta potential -31,03 ± 5,54 mV. These analyzes proved satisfactory since the particle diameter achieved by the preformed polymer interfacial deposition method used in nanocapsule production ranges from 250 to 500 nm (MORA-HUERTAS et. al., 2010), while the Zeta potential considered for a stable formulation should be bigger than 30 mV in modulus (RAVAL et al., 2019). Absorption and emission spectroscopy analyzes performed in the UV-Vis region found no changes in the steady state... (Complete abstract click electronic access below) / Mestre

No description available.

This thesis deals with the short story “Wanderer, kommst du nach Spa ...” (1950) by the German author Heinrich Böll (1917-1985). The well-established interpretation of this famous short story is that it deals with the dismal fact that the Nazis ended the development of Western culture, which cumulatively had been on its way since Greek antiquity. In this paper another reading is proposed, namely that the short story sheds light on the influence of the Romantic era in Germany and that a certain interpretation and use of Romanticism provided some of the seeds to the obscure ideas of the Nazi era. Research on Böll´s early writings is presented. The notion of cultural memory is introduced. The intertextual connections between Bölls text and other texts are being uncovered. Most fruitful proves the connection between “Wanderer” and the poem “Der Spaziergang” (1795) by Friedrich Schiller (1759-1805) to be. “Wanderer” can be read as a satirical version of Schillers poem. Reasons for Böll to choose Schiller’s elegy as a target are discussed at length. A parable in the story, ”wie ein Gesicht eines Schlafenden” / like a face of a sleeping person, unfolds an undertext to the short story, a Catholic text. Jesus, the Holy Communion, prayers and the eternal cross are present. Wanderer can be read as a requiem over the young soldier. Further, the inability of the wounded soldier to connect to his surroundings is interpreted as a parallell to Germany at the end of the war; the Nazis had stolen the Heimat from the people and it was no longer possible to interpret the world as something you belonged to. While Heinrich Böll on the surface of the text tries to recapture the German language from its nazi-poisend condition, the protagonist within the text regains his identity by means of his own handwriting - a part of his language.

A presente tese trata da análise conformacional e estudo das interações eletrônicas de algumas 2-(fenilselanil)-2-(metoxi)-4\'-substituídas-acetofenonas (série I) e das 2-(4-substituídasfenilsulfanil)-2-(metoxi)-4\'-substituídas-acetofenonas (série II) contendo grupos doadores, hidrogênio e atraentes de elétrons na posição para dos anéis fenacílico [4\'-Y-PhC(O)] e fenilsulfanílico (S-Ph-4-X). Através da resolução das bandas de νCO, foi constatada a ocorrência de isomerismo conformacional nos solventes de constante dielétrica crescente (n-C6H14, CCl4, CHCl3, CH2Cl2, CH3CN) em ambas as séries. Cinco compostos da série II apresentaram ressonância de Fermi (RF) no infravermelho e precisaram ser deuterados. Os dados espectroscópicos são concordantes tanto com os resultados dos cálculos de otimização e frequência em fase gasosa quanto com a simulação do efeito do solvente (PCM), no nível de teoria B3LYP/6-31+G(d,p). Em ambas as séries, foram encontradas três conformações estáveis c1, c2 e c3, sendo que c2 é significativamente mais estável que c1 e c3. O confôrmero c1 possui o oxigênio metoxílico e o carbonílico em sinperiplanar enquanto os grupos -SePh/- SPh estão em anticlinal. Os confôrmeros c2 e c3 possuem o hidrogênio metínico em sinperiplanar com a carbonila enquanto os grupos -OMe e -SePh/-SPh estão na anticlinal. O confôrmero c1 pode ser atribuído ao componente de banda (IR) de maior frequência νCO. Da mesma forma, c2 e c3 são o componente de frequência intermediária e de menor frequência, respectivamente, na série I enquanto que na série II eles coalescem em apenas um componente de menor frequência. Os cálculos de PCM mimetizam os dados espectroscópicos, i.e. é possível constatar a inversão populacional entre c1 e c2, conforme a polaridade do solvente aumenta. Através do cálculo de frequências anarmônicas e construção da PED, foram encontrados dois modos vibracionais que combinados interagem com νCO originando a RF (série II). Um modo é de alta frequência e envolve uma porcentagem considerável de &#948C-H(metínico), o outro modo é esqueletal. A análise das interações orbitalares (NBO) mostrou que os confôrmeros c1 e c2 são estabilizados pela transferência de cargas entre LpO5→σ*CS/Se (ca. 18 kcal mol-1) enquanto c3 é estabilizado pela interação menos intensa LpO5→σ*C-C (ca. 9,5 kcal mol-1). As interações eletrônicas foram investigadas a partir dos contatos interatômicoscurtos com apoio das cargas atômicas parciais. Apesar de c1 e c2 apresentarem praticamente a mesma estabilidade em termos de interações orbitalares, o primeiro é fortemente desestabilizado pela repulsão eletrostática entre os átomos O&#948-CO...O&#948-OMe negativamente carregados separados por uma distância menor que a soma dos raios de van der Waals. Este contato curto entre os dipolos C&#948+=O&#948- e C&#948+−O&#948- é responsável pela maior frequência de νCO de c1 frente c2 e c3. A maior estabilidade de c1 nos solventes mais polares, porém, deve-se à melhor solvatação local destes dipolos. As análises dos monocristais (raios-X) indicou que os compostos assumem, no estado sólido, a conformação menos estável c1, obtida em fase gasosa. Não foram encontradas diferenças significativas no que se refere aos substituintes Y e X. Conclui-se que a estabilidade global das conformações é determinada pelo balanço energético entre as interações orbitalares e eletrostáticas, nas duas séries estudadas. / This thesis reports the conformational analysis and the electronic interactions study of some 2-(phenylselanyl)-2-(methoxy)-4\'-substituted-acetophenones (series I) and 2-(4-substitutedphenylsulphanyl)-2-(methoxy)-4\'-substituted-acetophenones (series II) bearing electron donating, hydrogen and electron attracting substituents in the para position of the phenacyl [4\'-Y-PhC(O)] and phenylsulphanyl (S-Ph-4-X). The occurrence of conformational isomerism in crescent dielectric constant solvents (n-C6H14, CCl4, CHCl3, CH2Cl2, CH3CN) in the two series was studied through the νCO infrared band decomposition. From the series II compounds, five presented Fermi resonance (FR) and had to be deuterated. The spectroscopic data are in line with theoretical calculations results for optimization and frequency in gas phase as well as for solvent effect simulation (PCM), both in B3LYP/6-31+G(d,p) level. Three stable conformers (c1, c2 and c3) were found for both series being the c2 significantly more stable than c1 and c3. Particularly in the c1 conformer, the methoxyl and the carbonyl oxygens are in sinperiplanar orientation while the -SePh/-SPh groups are in anticlinal. In the c2 and c3 conformers the methyne hydrogen assume a sinperiplanar geometry with respect to the carbonyl whereas both -OMe and -SePh/-SPh are in anticlinal. The c1 conformer can be ascribed to the highest frequency νCO band component (IR). So, c2 and c3 ones can be ascribed to the medium and the lowest frequency νCO component, respectively, in the series I whereas in the series II they come together (coalescence) in one single band component. The PCM calculations are in good agreement with spectroscopic data i.e. it is possible to observe a populational inversion between c1 and c2 conformers as the solvent polarity increases. The anharmonic frequencies and PED theoretical treatment revealed that the combination of two vibrational modes interact with the νCO giving rise to the FR (series II): the high frequency one involves a considerable δC-H(methyne) percentage; whilst the other is skeletal. The orbital interactions analysis (NBO) showed that the c1 and c2 conformers are mainly stabilized by charge transfer LpO5→σ*CS/Se (ca. 18 kcal mol-1) while c3 is stabilized by the less intense interaction LpO5→σ*C-C (ca. 9,5 kcal mol-1). The electronic interactions were investigated by means of interatomic short contacts supported by partial atomic charges calculations. In contrast with the almost similar orbital interactions stability of c1 and c2, the former is strongly destabilized by the electrostatic repulsion between Oδ-CO...Oδ-OMe atoms which are negatively charged separated by a distance shorter than the van der Waals radius sum. This short contact between Cδ+=Oδ- and Cδ+−Oδ- dipoles is responsible for the highest νCO frequency of c1 compared to c2 and c3. In the other hand, the greater stabilization of c1 in the more polar solvents is due to the better solvation of those local dipoles. Last, but not least, the X-ray analysis showed that the compounds in the solid state assume the less stable conformation c1, obtained in gas phase. No significative differences were found in terms of the Y and X substituents. It is suggestive that an energetic balance between orbital and electrostatic interactions determines the global stability of conformations in both studied series.

A presente tese trata da análise conformacional e estudo das interações eletrônicas de algumas 2-(fenilselanil)-2-(metoxi)-4\'-substituídas-acetofenonas (série I) e das 2-(4-substituídasfenilsulfanil)-2-(metoxi)-4\'-substituídas-acetofenonas (série II) contendo grupos doadores, hidrogênio e atraentes de elétrons na posição para dos anéis fenacílico [4\'-Y-PhC(O)] e fenilsulfanílico (S-Ph-4-X). Através da resolução das bandas de νCO, foi constatada a ocorrência de isomerismo conformacional nos solventes de constante dielétrica crescente (n-C6H14, CCl4, CHCl3, CH2Cl2, CH3CN) em ambas as séries. Cinco compostos da série II apresentaram ressonância de Fermi (RF) no infravermelho e precisaram ser deuterados. Os dados espectroscópicos são concordantes tanto com os resultados dos cálculos de otimização e frequência em fase gasosa quanto com a simulação do efeito do solvente (PCM), no nível de teoria B3LYP/6-31+G(d,p). Em ambas as séries, foram encontradas três conformações estáveis c1, c2 e c3, sendo que c2 é significativamente mais estável que c1 e c3. O confôrmero c1 possui o oxigênio metoxílico e o carbonílico em sinperiplanar enquanto os grupos -SePh/- SPh estão em anticlinal. Os confôrmeros c2 e c3 possuem o hidrogênio metínico em sinperiplanar com a carbonila enquanto os grupos -OMe e -SePh/-SPh estão na anticlinal. O confôrmero c1 pode ser atribuído ao componente de banda (IR) de maior frequência νCO. Da mesma forma, c2 e c3 são o componente de frequência intermediária e de menor frequência, respectivamente, na série I enquanto que na série II eles coalescem em apenas um componente de menor frequência. Os cálculos de PCM mimetizam os dados espectroscópicos, i.e. é possível constatar a inversão populacional entre c1 e c2, conforme a polaridade do solvente aumenta. Através do cálculo de frequências anarmônicas e construção da PED, foram encontrados dois modos vibracionais que combinados interagem com νCO originando a RF (série II). Um modo é de alta frequência e envolve uma porcentagem considerável de &#948C-H(metínico), o outro modo é esqueletal. A análise das interações orbitalares (NBO) mostrou que os confôrmeros c1 e c2 são estabilizados pela transferência de cargas entre LpO5→σ*CS/Se (ca. 18 kcal mol-1) enquanto c3 é estabilizado pela interação menos intensa LpO5→σ*C-C (ca. 9,5 kcal mol-1). As interações eletrônicas foram investigadas a partir dos contatos interatômicoscurtos com apoio das cargas atômicas parciais. Apesar de c1 e c2 apresentarem praticamente a mesma estabilidade em termos de interações orbitalares, o primeiro é fortemente desestabilizado pela repulsão eletrostática entre os átomos O&#948-CO...O&#948-OMe negativamente carregados separados por uma distância menor que a soma dos raios de van der Waals. Este contato curto entre os dipolos C&#948+=O&#948- e C&#948+−O&#948- é responsável pela maior frequência de νCO de c1 frente c2 e c3. A maior estabilidade de c1 nos solventes mais polares, porém, deve-se à melhor solvatação local destes dipolos. As análises dos monocristais (raios-X) indicou que os compostos assumem, no estado sólido, a conformação menos estável c1, obtida em fase gasosa. Não foram encontradas diferenças significativas no que se refere aos substituintes Y e X. Conclui-se que a estabilidade global das conformações é determinada pelo balanço energético entre as interações orbitalares e eletrostáticas, nas duas séries estudadas. / This thesis reports the conformational analysis and the electronic interactions study of some 2-(phenylselanyl)-2-(methoxy)-4\'-substituted-acetophenones (series I) and 2-(4-substitutedphenylsulphanyl)-2-(methoxy)-4\'-substituted-acetophenones (series II) bearing electron donating, hydrogen and electron attracting substituents in the para position of the phenacyl [4\'-Y-PhC(O)] and phenylsulphanyl (S-Ph-4-X). The occurrence of conformational isomerism in crescent dielectric constant solvents (n-C6H14, CCl4, CHCl3, CH2Cl2, CH3CN) in the two series was studied through the νCO infrared band decomposition. From the series II compounds, five presented Fermi resonance (FR) and had to be deuterated. The spectroscopic data are in line with theoretical calculations results for optimization and frequency in gas phase as well as for solvent effect simulation (PCM), both in B3LYP/6-31+G(d,p) level. Three stable conformers (c1, c2 and c3) were found for both series being the c2 significantly more stable than c1 and c3. Particularly in the c1 conformer, the methoxyl and the carbonyl oxygens are in sinperiplanar orientation while the -SePh/-SPh groups are in anticlinal. In the c2 and c3 conformers the methyne hydrogen assume a sinperiplanar geometry with respect to the carbonyl whereas both -OMe and -SePh/-SPh are in anticlinal. The c1 conformer can be ascribed to the highest frequency νCO band component (IR). So, c2 and c3 ones can be ascribed to the medium and the lowest frequency νCO component, respectively, in the series I whereas in the series II they come together (coalescence) in one single band component. The PCM calculations are in good agreement with spectroscopic data i.e. it is possible to observe a populational inversion between c1 and c2 conformers as the solvent polarity increases. The anharmonic frequencies and PED theoretical treatment revealed that the combination of two vibrational modes interact with the νCO giving rise to the FR (series II): the high frequency one involves a considerable δC-H(methyne) percentage; whilst the other is skeletal. The orbital interactions analysis (NBO) showed that the c1 and c2 conformers are mainly stabilized by charge transfer LpO5→σ*CS/Se (ca. 18 kcal mol-1) while c3 is stabilized by the less intense interaction LpO5→σ*C-C (ca. 9,5 kcal mol-1). The electronic interactions were investigated by means of interatomic short contacts supported by partial atomic charges calculations. In contrast with the almost similar orbital interactions stability of c1 and c2, the former is strongly destabilized by the electrostatic repulsion between Oδ-CO...Oδ-OMe atoms which are negatively charged separated by a distance shorter than the van der Waals radius sum. This short contact between Cδ+=Oδ- and Cδ+−Oδ- dipoles is responsible for the highest νCO frequency of c1 compared to c2 and c3. In the other hand, the greater stabilization of c1 in the more polar solvents is due to the better solvation of those local dipoles. Last, but not least, the X-ray analysis showed that the compounds in the solid state assume the less stable conformation c1, obtained in gas phase. No significative differences were found in terms of the Y and X substituents. It is suggestive that an energetic balance between orbital and electrostatic interactions determines the global stability of conformations in both studied series.

L'une des étapes du procédé de conversion de l'UF₆ gazeux en UO₂ solide par voie sèche est la formation de poudre d'UO₂F₂ dans un jet coaxial triple UF₆/N₂/H₂O. Les caractéristiques de la poudre obtenue ont ensuite une influence sur les propriétés des pastilles d'UO₂ utilisées en réacteur nucléaire, d'où l'intérêt d'une bonne maîtrise de cette étape du procédé. L'étude présentée a pour but d'évaluer expérimentalement et de modéliser l'effet de divers paramètres sur les particules formées dans un jet coaxial turbulent suite à une réaction. On s'est notamment intéressé à l'influence sur les distributions granulométriques des vitesses absolues et relatives des gaz constituant le jet. Deux types d'études expérimentales ont été réalisés. Le développement des couches de mélange dans la région initiale du jet a d'abord été évalué à l'aide de mesures de température. des mesures de distributions granulométriques par turbidimétrie ont ensuite permis d'étudier les particules formées lors de l'hydrolyse de chlorures métalliques gazeux (SnCl₄, TiCl₄) dans un jet coaxial double ou triple. Une modélisation des phénomènes de mélange et de précipitation a été proposée. Elle prend notamment en compte le développement des couches de mélange, le mésomélange, le micromélange et la croissance des particules par agglomération. L'influence des paramètres opératoires, et en particulier des vitesses, apparaît différente pour les jets TICl₄/H₂O ET SnCl₄/H₂O. Une comparaison des résultats théoriques et expérimentaux semble indiquer que les particules formées par hydrolyse de TiCl₄ croissent essentiellement par agglomération alors qu'un autre phénomène de croissance parait impliqué pour les particules issues de l'hydrolyse de SnCl₄.

Cette recherche a été menée auprès d'étudiants de Classes Préparatoires aux Grandes Ecoles Scientifiques. Un de ses objectifs est d'analyser l'influence des variables motivationnelles sur la performance académique. L’auto-efficacité académique, l’orientation des buts et la motivation autodéterminée sont souvent citées pour leur rôle majeur dans la réussite universitaire. Ces variables sont issues de cadres théoriques distincts et nous souhaitons étudier comment elles s'influencent mutuellement. Des outils psychométriques, dont une échelle d’auto-efficacité académique, ont été créés et validés. Des analyses en pistes causales ont été effectuées afin de proposer un modèle traduisant les influences qui existent entre variables motivationnelles et performances académiques.Nos résultats montrent que :- l’auto-efficacité est la seule variable motivationnelle à avoir une influence directe sur les performances académiques ;- le but d’approche de la maîtrise est sous influence de l’auto-efficacité et une orientation vers ce type de but influence positivement la motivation intrinsèque et négativement l’amotivation ;- le but d’approche de la performance a une influence positive sur les différentes formes de motivation extrinsèque et, parmi ces dernières, la motivation extrinsèque à régulation identifiée influence positivement l’auto-efficacité tandis que la motivation extrinsèque à régulation externe l’influence négativement ;- l’amotivation influence négativement l’auto-efficacité académique ;- l’impact de l’amotivation sur les performances académiques est totalement médiatisée par l’auto-efficacité.Des prolongements de cette étude et certaines applications sont proposés. / This research has been carried out among French science students enrolled in CPGE (Classes Préparatoires aux Grandes Ecoles). One of its objectives is to study how motivational variables influence academic achievement. Academic self-efficacy, achievement goals or self-determined motivation are reported to play an important part in academic achievement. By relating self-efficacy, goal orientations and motivation, as conceptualized in self-determination theory, to both preceding and subsequent academic achievement, it is possible to further investigate the structural relation between these variables. Therefore, we aim at analysing the mutual influences which exist among them.Psychometric tools, among which an academic self-efficacy scale, were created and validated. Path analysis were performed in order to produce a multivariate model including motivational variables, previous academic performance and subsequent academic achievement. Our results showed that:- self-efficacy is the only motivational variable that directly influences academic achievement; - mastery approach goal, which is influenced by self-efficacy, enhances intrinsic motivation but is negatively related to amotivation;- performance approach goal enhances extrinsic motivation and identified regulated extrinsic motivation is positively related to self-efficacy while externally regulated extrinsic motivation is negatively related to it;- amotivation is negatively related to self-efficacy;- Self-efficacy beliefs are mediators between amotivation and subsequent academic achievement.Future research could build on these findings. Suggestions of applications are provided.