Yes / The literature on the imperativeness of government support for firm survival since the onset of COVID-19 is vast, but scholars have scarcely considered the impact of such assistance on managers' time, nor the extent to which support measures induce resilience and export activity. Accordingly, this study assesses the impact of government support on (1) bureaucracy and (2) resilience using data from 535 Moroccan SMEs. It further evaluates the influence of resilience on direct versus indirect exports, and espouses the institutional voids, resource-based and strategy-creation view to explain the associations through a contingency lens. The results demonstrate that (1) government support increases bureaucracy which, (2) surprisingly triggers and enhances resilience. Furthermore, (3) resilience has a positive impact on direct exports but (4) adversely affects indirect exports. Theoretically, the findings acquiesce extant calls for measurement specificity in export performance. Practically, stakeholders' attention is drawn to the value of managers' time well spent.

No / We present a numerical analysis of rendered pairs of rooms, in which the spectral power distribution of the illuminant in one room matched the surface reflectance function in the other room, and vice versa. We ask whether distinction between the rooms is possible and on what cues this discrimination is based. Using accurately rendered three-dimensional (3D) scenes, we found that room pairs can be distinguished based on indirect illumination, as suggested by A. L. Gilchrist and A. Jacobsen (1984). In a simulated color constancy scenario, we show that indirect illumination plays a pivotal role as areas of indirect illumination undergo a smaller appearance change than areas of direct illumination. Our study confirms that indirect illumination can play a critical role in surface color recovery and shows how computer rendering programs, which model the light¿object interaction according to the laws of physics, are valuable tools that can be used to analyze and explore what image information is available to the visual system from 3D scenes.

Les formes du temps chez Albert Cohen ont montré qu'il existe une interaction entre le temps chronologique romanesque et l'histoire écrite en filigrane l'ensemble des œuvres. Les différentes formes et modes d'expression du temps chez Cohen constituent le socle d'une écriture plurielle en contradiction avec son temps. L’œuvre de Cohen dépasse tous les clivages de la temporalité poétique, romanesque, lyrique, théâtrale, autobiographique, profane et sacrée pour atteindre une dimension universelle d'une construction du temps fondé sur la différence. Le récit a précisément pour rôle de permettre le décryptage du temps par l'homme à travers une expérience intime dont les différentes manifestations les plus fréquentes dans les romans cohéniens sont l'attente, la solitude, l'ennui et la mélancolie. Le moment intime est non seulement illimité mais il reste ouvert à plusieurs horizons ce qui permet d'ailleurs la cohabitation de multiples séquences spatio-temporelles. Avec l'Histoire, le temps admet deux réalités parallèles : une première, terrestre, à partir de laquelle l'homme commence à évaluer le temps chronologique et linéaire ; une seconde, mythique regroupant la première en lui donnant un ancrage dans le temps d'antan que l'écrivain régénère avec l'avènement d'un nouvel Adam. / Forms at the time Albert Cohen showed that there is an interaction between chronological time and history novels written between the lines of all works. Different forms and modes of expression of time in Cohen are the foundation of a plural writing in contradiction with the times. Cohen's work transcends all divisions of temporality poetic, romantic, lyrical, dramatic, autobiographical, profane and sacred dimension to achieve a universal construction based on the time difference. The History is precisely to allow the decryption part time by man through an intimate experience with the various manifestations common in novels cohéniens are waiting, loneliness, boredom and melancholy. The intimate moment is not only unlimited but it remains open in several horizons thereby also the coexistence of multiple spatio-temporal sequences. With history, time admits two parallel realities : first, land, from which he begins to evaluate the chronological time and linear second, involving the mythical first giving it a foothold in the time of old regenerates the writer with the advent of a new Adam.

L’objectif de la thèse est le développement d'une stratégie pour quantifier expérimentalement le bruit indirect et le séparer du bruit direct, puisque le bruit direct et indirect co-existent dans la plupart des applications. La configuration retenue pour l'étude est un banc expérimental avec une tuyère et la stratégie proposée a pour l’objectif de mesurer les fonctions de transfert de la tuyère. Le premier chapitre définit les fonctions de transfert de la tuyère utilisée dans l'étude comme référence pour la validation de la stratégie. Le deuxième chapitre présente une configuration originale qui génère simultanément le bruit direct et indirect sans introduire la combustion. Le troisième chapitre détaille les méthodes pour évaluer les ondes acoustiques et d'entropie à partir des mesures de température et de pression. Le quatrième chapitre termine la première partie de la thèse en décrivant la stratégie avant de la tester avec les signaux expérimentaux et numériques de haute fidélité. La deuxième partie se concentre sur l'utilisation de la stratégie dans les simulations à grandes échelles d'un brûleur à combustion turbulente. Les simulations sont validées par des données expérimentales tandis que les signaux sont traités à quantifier le bruit direct et indirect de combustion dans la chambre. / The objective of the thesis is the development of a practical strategy to quantify experimentally indirect noise and to discriminate it from direct noise as they co-exist in most practical conditions. The configuration retained for the study is a test bench with a nozzle and the proposed the strategy relies on nozzle transfer functions. The first chapter defines the nozzle transfer functions used in the study as references for the validation of the strategy. The second chapter introduces an original setup that generates simultaneously direct and indirect noise without handling combustion. The third chapter details the methods to evaluate the acoustic and entropy waves from raw temperature and pressure signals. The fourth chapter closes the first part of the study by describing the strategy then testing it on high-fidelity simulation and experimental signals. The second part focuses on the use of the strategy in Large Eddy Simulations of a turbulent combustion test bench. Simulations are validated by experimental data then raw signals are processed to quantify the direct and indirect noise sources as well as the direct and indirect noise contributions.

One of the dilemmas that information systems (IS) decision-makers encounter is the identification of the often hidden costs associated with IS adoption, particularly since most of them are reported to be external to the traditional IS budget. The review of the IS literature has identified that much effort to date has focused on the identification and measurement of direct costs, and that much less attention has been paid to indirect costs. One of the main problems reported in the literature associated with looking at indirect costs is that they are intangible and difficult to quantify, and there is evidence suggesting that these indirect costs are rarely completely budgeted for, and thus deserve a much closer consideration by decision-makers. This research investigates this view, arguing that one element of indirect costs, that is, indirect human costs (lRCs), is underestimated and little understood. The author argues that it is not possible to estimate or evaluate IHCs without first identifying all their components, yet there is an absence of models that show how such costs are allocated for IS adoption. This underpins the necessity of the present research. Proposed here is a framework of nine sequential phases for accommodating indirect human costs. In addition to this, 1) three conjectures, 2) cost taxonomy and 3) an interrelationship-mapping cost driver model of IRCs, are proposed based on the literature analysis and underpinning the conceptual phases of the framework. To test the conjectures and validate the models proposed, a case research strategy using case settings were carried out in the private sector. Empirical findings validates the models proposed and reveal that indirect human costs are perceived as costs associated with IS adoption, nevertheless not included in the evaluation process or investment proposals. However, during the empirical research, new cost factors and drivers emerged, which resulted in modifications being made to the previously proposed conceptual models. In doing so, it provides investment decision-makers with novel frames of reference and an extensive list of IRCs that can be used during both the IS budget proposals and the evaluation process of the IS investment.

Ecological communities are collections of species bound together by their influences on one another. Community structure, therefore, refers to the way in which these influences are organised. As a result, ecologists are mainly interested in the factors driving the structure, functioning, and persistence of communities. The traditional focus, however, has been on the feeding relationships among species (direct trophic interactions), whereas relationships mediated by a third species or the environment (indirect interactions) have been largely overlooked. I investigated the role of indirect interactions in structuring communities through a series of field experiments in a diverse assemblage of arthropods living on a Brazilian shrub species. I experimentally reduced the abundance of the commonest galler on the shrub and found that the perturbation resonated across the food web, affecting its structure and robustness. Since there was no potential for these effects to be propagated directly or indirectly via the documented trophic links, the effects must have spread non-trophically and/or through trophic links not included in the web. Thus, I investigated non-trophic propagation of effects in the system. I demonstrate that hatched galls of the commonest galler, which serve as habitat for other species, can mediate non-trophic interactions that feedback to the galler modifying its interactions with parasitoids and inquiline aphids. I performed further manipulative experiments, excluding ants, live galls and hatched galls, to reveal mechanisms for the non-trophic interaction modifications observed in this system. Finally, I explored how non-trophic interaction modification could affect the structure and stability of a discrete ecological community in the field. I investigated how the densities of certain pairs of groups relate to each other, and how their relationship changes in relation to a third group. Then, I assembled an "effect network" revealing, for the first time in an empirical community, a hidden web of non-trophic indirect interactions modifying the direct interactions and modifying each other. Overall, the thesis presents evidence that communities are strongly interconnected through non-trophic indirect interactions. This is one of the first empirical demonstrations of the context-dependent modification of interactions via non-trophic interactions. However, determining the mechanisms behind such interaction modifications may be unfeasible. Understanding how the observed effects relate to community structuring requires shifting our focus from bipartite interaction networks to a more holistic approach.

Le bruit émis par les nouvelles architectures de moteurs aéronautiques a été considérablement réduit dans les dernières années. Les différentes sources de bruit ont été identifiées et pour la plupart réduites. Cependant, la contribution relative du bruit de combustion au bruit global a augmenté progressivement avec la décroissance des autres sources. Deux mécanismes de génération de bruit de combustion ont été identifiés : le bruit direct qui est produit par des fluctuations du dégagement de chaleur dû à la combustion, et le bruit indirect qui est généré par l’accélération des spots d’entropie. Dans ce travail, les mécanismes de génération et propagation du bruit entropique sont étudiés par des simulations numériques aux grandes échelles (en anglais LES) et par des modèles analytiques. Dans un premier temps, une configuration simplifiée du phénomène est étudiée : des spots d’entropie sont créés par des résistances chauffantes et ensuite accélérés par une tuyère pour générer du bruit indirect. Cette configuration a été simulée et ses résultats validés par des campagnes expérimentales. Ensuite, la simulation numérique est utilisée pour mieux comprendre les mécanismes de génération du bruit indirect et ses interactions avec des effets visqueux et non visqueux. Dans une seconde partie, une configuration de turbine haute pression à un seul étage est utilisée pour étudier le bruit indirect d’une façon plus réaliste. Dans les deux parties de cette thèse, les résultats numériques sont comparés à des théories analytiques pour mieux comprendre les avantages et inconvénients d’une méthode par rapport à l’autre. / Combustion noise is increasing its relative contribution to aircraft noise, while other sources are being reduced and new low-NOx emission combustion chambers being built. Two mechanisms are responsible for this noise source: direct noise in which acoustic waves are generated by the flame and propagate to the outlet of the aero-engine, and indirect noise, where entropy waves generate noise as they are accelerated and decelerated in the turbine stages. In this work, the analytical models used for the propagation of waves through non-homogeneous flows, including the generation of indirect noise, are revised and extended. In the first part, the quasi-1D case is studied, extending the analytical method to non-zero frequencies and validating the results with numerical methods and experimental data. In the second part, the 2D method for the case of compact turbine blades is studied and validated using numerical simulations of a rotating blade and of a complete turbine stage. Finally, in the third part of this thesis, these models are combined with reactive and compressible Large Eddy Simulations (LES) of combustion chambers to build a hybrid approach, named CHORUS, able to predict combustion noise.

abstract: Time-to-event analysis or equivalently, survival analysis deals with two variables simultaneously: when (time information) an event occurs and whether an event occurrence is observed or not during the observation period (censoring information). In behavioral and social sciences, the event of interest usually does not lead to a terminal state such as death. Other outcomes after the event can be collected and thus, the survival variable can be considered as a predictor as well as an outcome in a study. One example of a case where the survival variable serves as a predictor as well as an outcome is a survival-mediator model. In a single survival-mediator model an independent variable, X predicts a survival variable, M which in turn, predicts a continuous outcome, Y. The survival-mediator model consists of two regression equations: X predicting M (M-regression), and M and X simultaneously predicting Y (Y-regression). To estimate the regression coefficients of the survival-mediator model, Cox regression is used for the M-regression. Ordinary least squares regression is used for the Y-regression using complete case analysis assuming censored data in M are missing completely at random so that the Y-regression is unbiased. In this dissertation research, different measures for the indirect effect were proposed and a simulation study was conducted to compare performance of different indirect effect test methods. Bias-corrected bootstrapping produced high Type I error rates as well as low parameter coverage rates in some conditions. In contrast, the Sobel test produced low Type I error rates as well as high parameter coverage rates in some conditions. The bootstrap of the natural indirect effect produced low Type I error and low statistical power when the censoring proportion was non-zero. Percentile bootstrapping, distribution of the product and the joint-significance test showed best performance. Statistical analysis of the survival-mediator model is discussed. Two indirect effect measures, the ab-product and the natural indirect effect are compared and discussed. Limitations and future directions of the simulation study are discussed. Last, interpretation of the survival-mediator model for a made-up empirical data set is provided to clarify the meaning of the quantities in the survival-mediator model. / Dissertation/Thesis / Doctoral Dissertation Psychology 2017

Les excitons spatialement indirects, en tant que bosons composites, sont des candidats prometteurs pour l'exploration des systèmes corrélés à N-corps. Ils possèdent une dipôle électrique intrinsèque et une variété de spin 4 fois dégénérée, et devraient former un condensat de Bose-Einstein au-dessous de quelques Kelvins. De récents résultats théoriques montrent que cette condensation doit se produire au sein des états optiquement noirs. Néanmoins les interactions peuvent créer un couplage cohérent vers une population brillante, rendant ainsi accessible la détection du condensat par le biais de sa photoluminescence. Nos expériences portent sur un gaz froid d'excitons indirects dans un double puits quantique. Les excitons sont photo-générés par une excitation laser et confinés dans un piège électrostatique. Nous avons observé une réduction de la population d'excitons brillants pour un gaz de densité fixe à basses températures. Ceci contraste fortement avec le comportement attendu d'un gaz froid soumis à la statistique de Maxwell-Boltzmann. Ces résultats expérimentaux sont confirmés par un modèle phénoménologique montrant que la condensation dans les états noirs est compatible avec le noircissement anormal observé. Une réduction de la température pourrait en principe amplifier ces signatures, cependant dans le GaAs l'interaction exciton-phonon permettant le refroidissement est fortement réduite pour des températures inférieures au Kelvin. Nous avons donc développé une technique permettant le contrôle in-situ du confinement des excitons indirects sans échauffement du gaz, ouvrant ainsi la voie à l'exploration du refroidissement évaporatif des excitons. / Spatially indirect excitons, being composite bosons, are attractive candidates to explore correlated many-body systems. They possess an inherent electric dipole and a four-fold spin manifold. Indirect excitons are expected to form a BEC below a few Kelvins. Recent theoretical results show this condensation must occur in optically dark states. Interactions, however, can lead to a coherent coupling to a bright population, rendering the condensate accessible through its PL. Here we report on a cold gas of indirect excitons in coupled quantum wells. indirect excitons are photo-generated through pulsed laser excitation. Indirect excitons are confined in an electrostatic traps. Thus, we are able to observe an anomaluos depletion of the bright state population for a fixed gas density at lower bath temperatures. This stands in stark contrast to the expected classical behavior of a cold gas of indirect excitons obeying Maxwell-Boltzmann statistics. The experimental results are confirmed by a phenomenological model showing that condensation into the dark state is compatible with the observed anomalous darkening. Reducing the gas temperature should reinforce these signatures. However, in GaAs exciton-phonon interaction is strongly reduced for sub-Kelvin temperatures. We have thus developed a technique to control the indirect excitons confinement in-situ. Our method does not increase the gas temperature and thus paves the way towards the exploration of evaporative cooling for indirect excitons.

Cette thèse est dédiée à l'interprétation théorique des expériences sur les gaz froids des excitons indirects dans des nanostructures semi-conductrices. La théorie proposée explique la formation de l'état des excitons macroscopiquement ordonnés ("MOES") et des taches lumineuses localisées dans les images de photoluminescence des excitons. Dans la première partie je montrerai que la séparation macroscopique de charge induite par laser mène à l'apparition d'un champ électrique situé dans le plan de la structure. A cause de ce champ les états quantiques 1s et 2p de l'exciton se croisent et son moment dipolaire s'incline. Par conséquent, l'exciton va se localiser à la frontière entre les deux domaines d'une charge différente, où le champ électrique est le plus fort. Ensuite, j'étudierai un gaz d'excitons mis dans de tels pièges bidimensionnels en négligeant sa structure de spin. J'analyserai la possibilité de la condensation de Bose-Einstein dans le système considéré en utilisant les méthodes puissantes de la théorie à N-corps développées pour des gaz atomiques. En me basant sur le Hamiltonien pour un segment du cercle bidimensionnel ("2D cigar"), je montrerai que la dispersion cohérente des excitons mène à l'autolocalisation accompagnée par une modulation périodique de la densité. L'idée principale de la théorie est, ensuite, de modéliser cet état périodique par une chaîne de condensats piégés (Le Modèle de Chaîne). Un tel modèle permettra de dire que le système peut exhiber la transition de phase de second ordre pour certaines valeurs du paramètre qui caractérise les interactions. La valeur critique de ce paramètre peut être trouvée en analysant le comportement des fluctuations de phase à la température nulle. Le nombre de condensats dans le régime où les interactions sont fortes est déterminé par la balance entre les contributions de l'énergie cinétique est l'entropie dans l'énergie libre du système. Le Modèle de Chaîne permettra aussi de révéler l'invariance d''échelle et l'universalité du phénomène. J'obtiendrai l'expression pour la température unique de la transition de phase dans le système excitonique et discuterai l'effet de désordre. Je finirai par une discussion du rôle des interactions à N-corps et des effets de spin dans la condensation de Bose-Einstein des excitons. Je proposerai un modèle de gaz idéal pour décrire les textures de polarisation linéaire observées autour de chaque tache lumineuse et chaque fragment de MOES. Selon ce modèle, le domaine central incohérent de tous ces objets est composé d'une glace excitonique quantique. / The present Thesis is devoted to theoretical interpretation of intriguing observations made recently in cold gases of indirect excitons in semiconductor quantum wells. The proposed theory provides simple intuitive explanation for the basic phenomenology of the macroscopically ordered exciton state (MOES) and the localized bright spots (LBS) in the exciton photoluminescense pattern. The Thesis is organized as follows.First, we provide an important insight into the formation process of the external ring and LBS. We show that the macroscopic charge separation induced by the photoexcitation results in appearance of an in-plane electric field in the vicinity of the boundary. The field hybridizes 1s and 2p quantum states of an indirect exciton, effectively tilting its dipole moment. Thus polarized exciton seeks for the regions with higher in-plane electric field and, hence, becomes localized at the ring-shaped boundary.As a next step, we consider a gas of spinless dipolar bosons put in such two-dimensional (2D) traps. We analyze the possibility for occurence of Bose-Einstein condensation (BEC) in the system under consideration by means of the powerful many-body theoretical methods developed for ultracold atomic gases. Starting from the Hamiltonian for a segment of the ring (2D cigar) we show, howthe coherent scattering of excitons can result in autolocalization accompanied by a buildup of the diagonal long-range order. The crucial point of the theory then consists in replacement of the periodic coherent state by a chain of harmonically trapped condensates (Chain Model). We argue, that for sufficiently strong contact interaction between the excitons the system can exhibit the true second order phase transistion at finite temperature. The critical value of the interaction parameter can be found by analyzing the behaviour of the quantum phase fluctuations at zero temperature. The number of condensates at the ring in the strongly interacting regime is defined by the balance between the kinetic energy and the entropy terms in the free energy of the system.Futhermore, the use of the Chain Model of the MOES allows one to reveal scale invariance and universality of the pnenomenon. We obtain the expression for the unique critical temperature of the second order phase transition in the exciton system and discuss the effect of disorder.Finally, we comment on the role of many-body interactions and spin degrees of freedom in excitonic BEC. We suggest that each bead (or, equivalently, LBS) has the internal structure: it consists of a solid core (Quantum Exciton Iceberg) surrounded by a coherent exciton fluid. We develop an ideal gas model for the coherent four-component exciton fluid which allows one to explain the measured linear polarization patterns.