Dissertations / Theses on the topic 'QSSA'

In this thesis we study stochastic modeling and simulation methods for biochemical systems. The thesis is focused on systems with multi-state and multi-scale features and divided into two parts. In the first part, we propose new algorithms that improve existing multi-state simulation methods. We first compare the well known Gillespie\\\'s stochastic simulation algorithm (SSA) with the StochSim, an agent-based simulation method. Based on the analysis, we propose a hybrid method that possesses the advantages of both methods. Then we propose two new methods that extend the Network-Free Algorithm (NFA) for rule-based models. Numerical results are provided to show the performance improvement by our new methods. In the second part, we investigate two simulation schemes for the multi-scale feature: Haseltine and Rawlings\\\' hybrid method and the quasi-steady-state stochastic simulation method. We first propose an efficient partitioning strategy for the hybrid method and an efficient way of building stochastic cell cycle models with this new partitioning strategy. Then, to understand conditions where the two simulation methods can be applied, we develop a way to estimate the relaxation time of the fast sub-network, and compare it with the firing interval of the slow sub-network. Our analysis are verified by numerical experiments on different realistic biochemical models.
Ph. D.

In this thesis we study modeling and simulation approaches for multiscale biochemical systems. The thesis addresses both modeling methods and simulation strategies. In the first part, we propose modeling methods to study the behavior of the insulin secretion pathway. We first expand the single cell model proposed by Bertram et. al. to model multiple cells. Synchronization among multiple cells is observed. Then an unhealthy cell model is proposed to study the insulin secretion failure caused by weakening of mitochondria function. By studying the interaction between the healthy and unhealthy cells, we find that the insulin secretion can be reinstated by increasing the glucokinase level. This new discovery sheds light on antidiabetic medication. In order to study the stochastic dynamics of the insulin secretion pathway, we first apply the hybrid method to model the discrete events in the insulin secretion pathway. Based on the hybrid model, a probability based measurement is proposed and applied to test the new antidiabetic remedy. In the second part, we focus on different simulation schemes for multiscale biochemical systems. We first propose a partitioning strategy for the hybrid method which leads to an efficient way of building stochastic cell cycle models. Then different implementation methods for the hybrid method are studied. A root finding method based on inverse interpolation is introduced to implement the hybrid method with three different ODE solvers. A detailed discussion of the performance of these three ODE solvers is presented. Last, we propose a new strategy to automatically detect stiffness and identify species that cause stiffness for the Tau-Leaping method, as well as two stiffness reduction methods. The efficiency is demonstrated by applying this new strategy on a stiff decaying dimerization model and a heat shock protein regulation model.
Ph. D.

Clostridium acetobutylicum is renowned for the ability to convert sugars into acids and solvents, including the potential biofuel butanol. However, regulation of its fermentation metabolism remains poorly understood, especially regarding the shift from acid to solvent metabolism. Several RNPP-type cell-cell communication systems have recently been discovered within C. acetobutylicum ATCC 824. The aim of this study was to investigate one such system, Quorum Sensing System B (QssB), consisting of a regulator, QsrB, and a signalling peptide of unknown structure derived from a precursor protein, QspB. The primary objectives were to characterise this system in greater detail, its effects on metabolism and endospore formation, and to gain insights into the nature of the signalling process. Overexpression of qsrB confirmed a dramatic reduction of solvent production and sporulation, and revealed increased production of acetate and butyrate, with considerably decreased consumption of glucose. These phenotypes were overcome by the addition of synthetically produced peptides matching the C-terminal region of the conjugate signalling peptide QspB. In doing so, the minimum peptide sequence required to relieve the effects of qsrB overexpression was shown to be the heptamer AEPTWGW. The system was shown to be highly selective for this sequence, with an alanine scan showing the sequential reduction in biological activity. QssB did not engage in cross talk with the other RNPP-type systems present within the organism, or with a homologous system discovered in Clostridium roseum, further evidence of selectivity. Attempts were made to identify the Specific Binding Protein (SBP) required for QspB uptake via ABC transport. ClosTron mutation of two SBP encoding genes, CA_0176 and CA_C3632, conferred resistance to the effects of QsrB overproduction on sporulation. An iTRAQ-based proteomics approach was used to study the wider effects of qsrB overexpression, as well as their alleviation via synthetic peptide. This analysis confirmed that the qsrB overexpressing strain remained in an acidogenic state which could be overcome though peptide addition. Although glucose consumption was decreased upon QsrB overproduction, key glycolysis enzymes were found to be upregulated. The stationary phase regulator CA_C0957 was found to be downregulated under these conditions, whereas proteins associated with motility and chemotaxis increased in abundance. GusA reporter assays supported the former, whilst swimming and swarming assays remained inconclusive. Enzyme assays revealed increased acetate and butyrate kinase activity, agreeing with the acidogenic state suggested from the iTRAQ analysis. QsrB was confirmed to be a repressor of solvent production and the production of endospores, with new evidence indicating further complexity.

The generic concept of quasi-single-stage (QSS) power conversion topology for ac-dc rectification and dc-ac inversion is proposed. The topology is reached by direct cascading and synchronized switching of two variety of buck or two variety of boost switching networks. The family of QSS power converters feature single-stage power processing without a dc-link low-pass filter, a unidirectional pulsating dc-link voltage, soft-switching capability with minimal extra commutation circuitry, simple PWM control, and high efficiency and reliability. A new soft-switched single-phase QSS bi-directional inverter/rectifier (charger) topology is derived based on the QSS power conversion concept. A simple active voltage clamp branch is used to clamp the otherwise high transient voltage on the current-fed ac side, and at the same time, to achieve zero-voltage-switching (ZVS) for the switches in the output side bridge. Seamless four-quadrant operation in the inverter mode, and rectifier operation with unity power factor in the charger (rectifier) mode are realized with the proposed uni-polar center-aligned PWM scheme. Single-stage power conversion, standard half-bridge connection of devices, soft-switching for all the power devices, low conduction loss, simple center-aligned PWM control, and high reliability and efficiency are among its salient features. Experimental results on a 3 kVA bi-directional inverter/rectifier prototype validate the reliable operation of the circuit. Other single-phase and three-phase QSS bi-directional inverters/rectifiers can be easily derived as topological extensions of the basic QSS bi-directional inverter/rectifier. A new QSS isolated three-phase zero-voltage/zero-current-switching (ZVZCS) buck PWM rectifier for high-power off-line applications is also proposed. It consists of a three-phase buck bridge switching under zero current and a phase-shift-controlled full-bridge with ZVZCS, while no intermediate dc-link is involved. Input power and displacement factor control, input current shaping, tight output voltage regulation, high-frequency transformer isolation, and soft-switching for all the power devices are realized in a unified single stage. Because of ZVZCS and single-stage power conversion, it can operate at high switching frequency while maintaining reliable operation and achieving higher efficiency than standard two-stage approaches. A family of isolated ZVZCS buck rectifiers are obtained by incorporating various ZVZCS schemes for full-bridge dc-dc converters into the basic QSS isolated buck rectifier topology. Experimental and simulation results substantiate the reliable operation and high efficiency of selected topologies. The concept of charge control (or instantaneous average current control) of three-phase buck PWM rectifiers is introduced. It controls precisely the average input phase currents to track the input phase voltages by sensing and integrating only the dc rail current, realizes six-step PWM, and features simple implementation, fast dynamic response, excellent noise immunity, and is easy to realize with analog circuitry or to integrate. One particular merit of the scheme is its capability to correct any duty-cycle distortion incurred on only one of the two active duty-cycles which often happens in the soft-switched buck rectifiers, another merit is the smooth transition of the input currents between the 60o sectors. Simulation and preliminary experimental results show that smooth operations and high quality sinusoidal input currents in the full line cycle are achieved with the control scheme.
Ph. D.

Pseudomonas aeruginosa est une bactérie pathogène opportuniste extracellulaire. La souche PAO1 de P. aeruginosa possède trois loci codant des Systèmes de Sécrétion de Type VI (T6SS) indépendants, nommés H1 à H3-T6SS. Le premier d'entre eux, H1-T6SS, a été largement décrit dans la littérature scientifique et injecte des toxines à activité antiprocaryote dans d'autres bactéries permettant une défense active contre l'attaque d'un T6SS d'une autre bactérie. Les deux autres T6SS de P. aeruginosa sont probablement des facteurs de virulence de cette bactérie, mais aucun effecteur sécrété, ni cible intracellulaire ou rôle n'ont été proposés jusqu'ici. Dans ce travail de thèse, nous avons mis en évidence que la machinerie H2-T6SS permet l'invasion de cellules non-phagocytaires et participe à la virulence de P. aeruginosa. Cette entrée requière la dynamique du réseau de microtubules, via VgrG2b injectée par la machinerie H2-T6SS dans les cellules épithéliales, et capable de cibler les complexes de gamma-tubulines, centre nucléateur des microtubules. Il s'agit d'un mécanisme d'internalisation tout à fait original et jamais encore décrit. Nous avons également exploré la régulation croisée entre H2 et H3-T6SS. Enfin par une analyse de « RNAseq », nous avons observé entre les souches PAO1 et PA14 de P. aeruginosa une expression différentielle de nombreux gènes, certains codant des facteurs de virulence. Pour près de 30% d'entre eux, l'origine de cette variation reposerait sur une quasi-absence d'expression dans la souche PA14 de qslA, codant un anti-activateur du Quorum-Sensing. Ceci serait une nouvelle explication du phénotype hyper-virulent de la souche PA14 de P. aeruginosa
Pseudomonas aeruginosa is an opportunistic extracellular pathogen. The PAO1 strain of P. aeruginosa harbors three loci encoding independent Type VI Secretion Systems (T6SS), named H1 to H3-T6SS. H1-T6SS has been widely described in the literature and injects toxins with antiprokaryotic activity in target bacteria, allowing an active defense against the attack of a T6SS from another bacterium. The other two T6SS of P. aeruginosa are likely virulence factors, but no secreted effector or intracellular target or role have been proposed so far.In this work, we demonstrated that the H2-T6SS machinery triggered the invasion of non-phagocytic epithelial cells and is involved in the virulence of P. aeruginosa. This uptake is mediated by the microtubule network dynamics, and via VgrG2b, injected by the H2-T6SS machinery in epithelial cells, to target the gamma-tubulin complex, the microtubule nucleating center. This is an original mechanism of internalization never described before. We also studied the cross-regulation between H2 and H3-T6SS. Finally through a « RNAseq » analysis, we observed differential expression of many genes, including some encoding virulence factors, between PAO1 and PA14 strains of P. aeruginosa. For nearly 30% of them, the origin of this variation is an almost lack of expression in the PA14 strain of qslA, encoding an anti-Quorum Sensing activator. This can be a new explanation of hyper-virulent phenotype of the PA14 strain of P. aeruginosa

Long haulage of heavy-duty trucks weighing over 15-ton stands for nearly 50% of the fuelconsumption among trucks, making them the most fuel consuming category. This indicatesthe potential benefits in improving the fuel efficiency for said category. Hybridization is onepossible solution.Hybrid vehicles are vehicles with two or more power sources in the powertrain. Differentpowertrain configurations, hybridization levels and hybrid concepts are best suitedfor different applications. With prices for fossil fuels constantly rising hybridization is animportant technology to improve fuel efficiency.Different variations of configurations and concepts enables many choices when decidingon a hybrid driveline. A simulation tool for efficiently comparing various hybrid drivelineswould be a great asset when deciding on a configuration for a certain vehicle application. Forthis thesis the application in focus is the previously mentioned category, a heavy duty longhauler weighing 36-ton.The modeling approach used for the simulation tool is called quasistatic modeling or"backward modeling". This name comes from, based on a chosen drive cycle, the resistingforces which act on the vehicle can statically be calculated at each step from the velocityprofile. The required power to drive along the drive cycle can then be calculated backwardswithin the powertrain resulting in a fuel consumption for the combustion engine. For thisthe free QSS-toolbox for Matlab Simulink has been used as a base and modified when needed.The configuration chosen to be implemented is a parallel electric hybrid and was chosenfor its good characteristics for the type of driving highways provide. For this configurationtwo types of controllers are used, one being an Equivalent Consumption Minimization Strategycontroller and the other a simple, rule based heuristic controller.The results for both controllers show small benefits with hybridization of the longhauler compared with the conventional which in the long run would make bigger differencebecause of the large consumption in whole. A sensitivity analysis was also done showingthat improving conventional vehicle parameters can be as beneficial as hybridization.

Using a new implementation of a NASA flight simulation of the Quiet Short-Haul Research Aircraft, autopilots were designed to be capable of flying both straight in (ILS) approaches, and circling (SNI) approaches. A standard glideslope coupler was sufficient for most conditions, but a standard Proportional-Integral-Derivative (PID) based localizer tracker was not sufficient for maintaining a lateral track on the SNI course. To track the SNI course, a feed-forward system, using GPS steering provided much better results. NASA and the FAA embrace the concept of a Simultaneous, Non-Interfering (SNI) approach as a way to increase airport throughput while reducing the noise footprints of aircraft on approach. The NASA concept for the SNI approach for Short Takeoff and Landing (STOL) aircraft involves a straight in segment flown above the flight path of a normal approach, followed by a spiraling descent to the runway. As this is a procedure that would be utilized by regional airliners, it is assumed that it would be conducted under Instrument Flight Rules (IFR). GPS or INS guidance would be required to fly this approach, and it is likely that it would be necessary to fly the approach with a coupled autopilot: a stabilized, curving, instrument approach to decision altitude would be exceedingly difficult to fly. The autopilots in many current commuter and general aviation aircraft, however, were designed before the event of GPS, and do not have provisions for tracking curved paths. This study identifies problem areas in implementing the SNI circling approach on aircraft and avionics as they stand today and also gives examples of what can be done for the SNI approach to be successful.

In this thesis, theoretical investigation of nickel-like tin plasma is presented. X-ray production in a plasma medium produced by a laser beam is reviewed. Applications mostly, lithography are discussed. Two different schemes for x-ray lasing, namely, quasi-steady state and transient collisional excitation are explained and compared. The computer codes that are used for plasma, especially for laser produced plasma and x-ray laser including hydrodynamic codes, ray-trace codes and collisional radiative codes are discussed. The code used in this work, EHYBRID, is considered in more detail. An experimental setup which can allow x-ray lasing is designed for different plasma and laser parameters are analyzed by means of EHYBRID code. Results are briefly discussed and as a future work the realization of the related experiment is mentioned.

The objectives of this research work are to investigate, design and implement circularly-polarized antennas to be used for handheld satellite mobile communication and wireless sensor networks. Several antennas such as Quadrifilar Spiral Antennas (QSAs), two arm Square Spiral and stripline or coaxially-fed microstrip patch antennas are developed and tested. These antennas are investigated and discussed to operate at L band (1.61-1.6214GHz) and ISM band (2.4835-2.5GHz) A substantial size reduction was achieved compared to conventional designs by introducing special modifications to the antenna geometries. Most of the antennas are designed to produce circularly-polarized broadside-beam except for wireless sensor network application a circularly-polarized conical-beam is considered. The polarization purity and Specific Absorption Rate (SAR) of two dual-band antennas for satellite-mobile handsets next to the human head are investigated and discussed, using a hybrid computational method. A small distance between the head and the handset is chosen to highlight the effects of the relatively high-radiated power proposed from this particular antenna. A Genetic Algorithm in cooperation with an electromagnetic simulator has been introduced to provide fast, accurate and reliable solutions for antenna design structures. Circularly-polarized quadrifilar helical antenna handset and two air-dielectric microstrip antennas were studied. The capabilities of GA are shown as an efficient optimisation tool for selecting globally optimal parameters to be used in simulations with an electromagnetic antenna design code, seeking convergence to designated specifications. The results in terms of the antenna size and radiation performance are addressed, and compared to measurements and previously published data.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The Morita-Baylis-Hillman Adducts (MBHA) is a class of molecules studied by our research group on synthetic, theoretical and bioactivity aspects. In this work, we present Quantitative Structure-Activity Relationship (QSAR) models involving 32 aromatic MBHA. Initially, the most stable conformations of thirty-two MBHA were investigated by theoretical methods, which were used to construct models. For this study, were obtained potential energy curves using AM1 semi-empirical method, considering rotational degrees of freedom (sigma bonds). From these curves, the less energy conformation to each molecule was selected and optimized at B3LYP/6- 31+G(d) level, considering solvent effects through Polarizable Continuum Model (PCM). Proton Nuclear Magnetic Ressonance data are in agreement with the conformational study. Intramolecular Hydrogen Bonds (IHB) are presents in the most of the studied compounds, according to structural characterization and QTAIM calculations. Curiously, compounds that showed hydrogen bonds involving the nitro and hydroxyl groups have the best values of biological activity (IC50). An explanation is based on redox mechanism of action of nitrocompounds. NBO (Natural Bond Orbital) charges and LUKO (Lowest Unoccupied Kohn-Sham Orbitals) analysis at the ortho-nitro group are in agreement with these analyses. Considering quantum calculations and structural observations, four descriptors were selected a priori and submitted to a QSAR study using PLS (Partial Least Squares) and MLR (Multiple Linear Regression) modeling. A second QSAR approach was made from the another set of descriptors obtained through the online platform E-DRAGON, which were submitted to a variable selection method. The quality parameters obtained for models indicate that both are robust and predictive.
Os Adutos de Morita-Baylis-Hillman (AMBH) compreendem uma classe de moléculas investigadas por nosso grupo de pesquisas nos aspectos sintéticos, teóricos e de bioatividade. Neste trabalho, apresentamos modelos de Relação Quantitativa entre a Estrutura Química e a Atividade Leishmanicida (QSAR) envolvendo 32 AMBH aromáticos. Deste modo, inicialmente foram investigadas as conformações mais estáveis de cada composto através de métodos teóricos, as quais foram utilizadas na construção dos modelos. Foram obtidas curvas de energia potencial utilizando o método semi-empírico AM1, considerando graus de liberdade rotacionais (ligações sigma). A partir destas curvas, a conformação de menor energia para cada molécula foi selecionada e otimizada ao nível B3LYP/6-31+G(d), considerando os efeitos do solvente aquoso usando PCM ( Polarizable Continuum Model ). Dados espectroscópicos de Ressonância Magnética Nuclear de prótons corroboraram o estudo conformacional. Ligações de Hidrogênio Intramoleculares (LHI) se mostraram presentes na maioria das moléculas estudadas, conforme caracterização estrutural e cálculos QTAIM ( Quantum Theory Atoms in Molecules ). Curiosamente, os compostos que apresentaram Ligações de Hidrogênio envolvendo o grupo nitro (NO2) e a hidroxila (OH) possuem melhores valores de atividade biológica (menor IC50). Uma explicação está baseada no mecanismo de ação redox de nitrocompostos. Observação das cargas NBO ( Natural Bond Orbitals ) e análise dos orbitais de fronteira LUKO ( Lowest Unoccupied Kohn-Sham Orbitals ) ao nível do grupo orto-nitro estão de acordo com estas análises. Considerando os cálculos quânticos, bem como observações estruturais, quatro descritores foram selecionados a priori e submetidos a um estudo QSAR ( Quantitative Structure- Activity Relationships ) utilizando modelagem PLS ( Partial Least Squares ) e MLR ( Multiple Linear Regression ). Uma segunda abordagem QSAR foi realizada a partir de outro conjunto de descritores obtidos através da plataforma online E-DRAGON, os quais foram submetidos ao método de seleção de variáveis OPS ( Ordered Predictor Selection ). Os parâmetros de qualidade obtidos para os modelos indicam que ambos são robustos e preditivos.

This research thesis focuses on the experiences of pre-service drama teachers and considers how process drama may assist them to reflect on key aspects of professional ethics such as mandatory codes or standards, principled moral reasoning, moral character, moral agency, and moral literacy. Research from higher education provides evidence that current pedagogical approaches used to prepare pre –professionals for practice in medicine, engineering, accountancy, business, psychology, counselling, nursing and education, rarely address the more holistic or affective dimensions of professional ethics such as moral character. Process drama, a form of educational drama, is a complex improvisational group experience that invites participants to create and assume roles, and select and manage symbols in order to create a fictional world exploring human experience. Many practitioners claim that process drama offers an aesthetic space to develop a deeper understanding of self and situations, expanding the participant’s consciousness and ways of knowing. However, little research has been conducted into the potential efficacy of process drama in professional ethics education for pre-professionals. This study utilizes practitioner research and case study to explore how process drama may contribute to the development of professional ethics education and pedagogy.

碩士
國立高雄應用科技大學
工業工程與管理系碩士班
101
Today in twenty first century, the advancement of technology and networking is very fast. As the enterprise faces Internet networking and international fierce competition, how to remain invincible and to continuously innovate and grow is a big challenge. Thus, e-business has become the enterprise mainstream, e.g., enterprise resource planning (ERP) a kind of decision support system for e-business built on the basis of information systems by using the electronic networking technology to efficiently integrate the enterprise’s internal resources and external environments so that the performance of enterprise resources can be maximized. In Taiwan, in the past not a few medium and large enterprises (MLE) use their huge resources to build ERP system, and recently more and more SMEs also become involved in this system. In spite of this, as enterprises launch and implement the system, except the factors of lack experience, perception not right, or method not good, often due to industries’ specific characteristics, it may discount the expected performance. Because of that, this study attempts to employ ERP system in terms of launch method and process by the traditional industry’s case firm of Taiwan Aluminum Doors to seek the best management model for e-business in traditional SME enterprises. Therefore, this study aims to explore the multi-launch success case of ERP system in the traditional SMEs, where we attempts to understand the process from the first stage failure of launching ERP system to the second stage success in the aluminum window and door industry. As the literature indicates, there is not much academic research for ERP systems in SMEs. Thus, the way of launching ERP system based on MLEs’ success launch model and failure experience appear obviously important. In addition, there exist several predicaments in our domestic aluminum window and door industry, such as the causes of low use efficiency of firm’s internal data, independently enclosed external information, and the operation styles of traditional aluminum doors and windows industry, plus without transforming the localized industry to the networking internationalized, making the launch of ERP system not easy to succeed. This case study uses German Systems, Applications and Products in Data Processing (SAP) mainly with Accelerated SAP (i.e., ASAP) launch methodology, in the case example that failed in the first stage of launch, and then after conducting the diagnosis became successful in the second stage. After that, it employs the benefits of information integration, decision support, and process reengineering as performance indicators to predict the benefits brought in after the system was formally on line. The results in this study show that for the traditional SMEs it can use multi-launch to seek the ERP system’s launch success models, and provide aluminum doors and windows industry or other traditional industries with a reference to launch e-business.

Although parenting by lesbian, gay, and bisexual-identified (LGB) individuals has attracted increasing research attention over the past few decades, relatively little focus has been given to the personal identity development of adolescents raised in such families. There is scant qualitative data that describes the phenomenon from the viewpoint of Canadian adolescents; this study aims to give voice to those with parents that identify as non-heterosexual. In semi- structured interviews, participants were asked to explain how they made sense of being from an LGB-led family, particularly within the contexts of school and Canadian society, and of what unique needs they perceived families like theirs to have. For inclusion in the study, each participant needed to have at least one LGB-identified parent. Additionally, they needed to be a current or recent student in an Ontario secondary school. A convenience sampling method was used to locate nine (N=9) participants. Three of the participants were male, and six were female. All participants were Canadian-born English speakers who ranged in age from 13 to 19 years old, with a mean age of 17.5. The interview schedule was constructed with input from existing narrative psychology literature, consultation with fellow students and faculty, and inspiration from other semi- structured protocols such as The Life Story Interview (McAdams, 2008). Interpretative Phenomenological Analysis (IPA) was employed to organize and evaluate responses. Thematic findings were organized within three domains. First, family-related themes were considered, such as interviewees’ responses to parental disclosures of an LGB identity, responses of extended family members, and perceived advantages of having LGB-identified parents. Second, school-related themes were found, such as how children choose to disclose their parents’ sexual identity to peers. Finally, themes related to queer identity were considered, since many participants revealed their parents’ sexual identity intersected with other narratives (e.g., being Canadian, being heterosexual, the master narrative of heteronormativity, etc.) to create multiple layers to their own sense of self. The study endeavours to add a qualitative approach to the literature so that Canadian adolescents’ narratives are represented in the overall understanding of the phenomenon of LGB- led families. It also has potential to impact the development of school policies and curricula and to enrich the quality of life for LGB-led families.

Orientação: Joana Brites Rosa
O ensino superior é num primeiro momento marcado por muitas expetativas mas é também um longo percurso onde podem surgir situações problemáticas, diferentes consoante as etapas. O objetivo principal deste estudo foi o de compreender de que modo a ansiedade aos exames, por parte dos estudantes universitários, pode ser estudada, tendo em conta o stresse académico, as estratégias de coping e a satisfação académica. A amostra foi constituída por 187 estudantes da Universidade Lusófona de Humanidades e Tecnologias, sendo a média de idades 24,0 anos (DP=7,56) para o sexo feminino e de 25,2 anos (DP=8,00) para o sexo masculino. Procedeu-se a uma caraterização sociodemográfica da amostra e recorreu-se à aplicação de quatro instrumentos: o Student Stress Inventory, SSI (Dobson e Metcalfe, 1983), o Reactions to Tests, RTT (Irwin G. Sarason, 1984), o Brief Cope, COPE (J. L. Pais Ribeiro e A. P. Rodrigues, 2004) e o Questionário de Satisfação Académica, QSA (Soares e Almeida, 2001). Conclui-se que ao nível do stresse académico, na variável exigências da vida académica as mulheres apresentam valores mais elevados do que os homens. Na incerteza face ao futuro, pressões avaliativas e pressões parentais não se verificaram diferenças estatisticamente significativas. A ansiedade aos exames mostrou-se correlacionada com o stresse académico, com algumas estratégias de coping e de forma negativa com a satisfação académica.
Higher education is at first marked by many expectations but is also a long way problematic situations may arise where, depending on the different stages. The main objective of this study was to understand the examinations that anxiety on the part of college students so can be studied taking into account the academic stress, coping strategies and academic satisfaction. The sample consisted of 187 students from of Lusófona University, with being average 24,0 (SD=7,56) for females and 25,2 (SD= 8,00) for the male. A socio-demographic characterization of the sample was carried out and four measures were used SSI (Dobson e Metcalfe, 1983), RTT (Irwin G. Sarason, 1984), COPE (J. L. Pais Ribeiro e A. P. Rodrigues, 2004) and QSA (Soares e Almeida, 2001). It was concluded that on the academic stress, women present higher scores on the variable demands of academic life than compared to men. It not was found significant differences in the uncertainty regarding future, evaluative pressures and parental pressures there were no statistically significant differences. The anxiety of the examinations showed to be correlated with academic stress, with some coping strategies and negatively with academic satisfaction.