Stereotype threat is defined as a sociopsychological threat evoked by an evaluative situation in which a negative stereotype about one's group could be confirmed (Steele, 1997). While the deleterious effects of stereotype threat have been demonstrated numerous times in laboratory settings (McKay, Doverspike, Bowen-Hilton, & Martin, 2002; Ngyuen & Ryan, 2008; Spencer, Steele & Quinn, 1999; Steele & Aronson, 1995), generalization to actual testing situations has been limited (Stricker & Ward, 2004). The current study sought to increase ecological validity by examining stereotype threat among racial/ethnic minority students undergoing assessment using the Wechsler Adult Intelligence Scale-IV (WAIS-IV) without explicit priming. Another aim was to reduce stereotype threat by emphasizing the malleability of intelligence, as recommended by previous researchers (Aronson, Fried, & Good, 2002; Good, Aronson, & Inzlicht, 2003). Additionally, the relationship of ethnic identity to stereotype threat and test performance and the role of anxiety, a proposed mechanism of stereotype threat, were examined. Participants were also interviewed about their experiences of stereotype threat using a phenomenological approach. A 2(condition) x 3(race/ethnicity) experimental design was used, and 138 college students were randomized to the control or malleability conditions. Due to manipulation failure, the hypothesis that African and Latino American students would experience less stereotype threat and perform better on the WAIS-IV in the malleability condition could not be tested. Qualitative findings suggested that while participants endorsed perceptions of stereotype threat in general societal settings, they did not report stereotype threat while undergoing the WAIS-IV. The hypothesis that ethnic identity moderates the relationship between stereotype threat and performance received mixed support: ethnic identity-affirmation interacted with perceived stereotype threat on Digit Span, but all other interactions were nonsignificant. Lastly, the hypothesis that anxiety mediates the relationship between perceived stereotype threat and WAIS-IV performance was not supported. However, post-hoc analyses suggested that perceived stereotype threat mediates the relationship of anxiety and WAIS-IV performance. Correlational results revealed that perceived stereotype threat and stereotype vulnerability were related to WAIS-IV scores. In addition, students of color reported greater test and state anxiety than their European American counterparts. Implications for researchers, test administrators, and admissions officers are discussed. / text

A dissertação analisa Daniel Deronda, de George Eliot, identificando o conceito de maleabilidade como idéia chave para o entendimento dos ideais morais do romance. Discussão do papel desempenhado pelo conceito de maleabilidade no processo de transição da infância para a idade adulta e na apreensão especifica da amizade apresentados no romance / A study of George Eliots Daniel Deronda identifying the concept of malleability as the key idea for understanding the moral ideals in the novel. Discussion of the role malleability plays in the process of transition from childhood to adulthood and in the specific view of friendship presented in the novel

A dissertação analisa Daniel Deronda, de George Eliot, identificando o conceito de maleabilidade como idéia chave para o entendimento dos ideais morais do romance. Discussão do papel desempenhado pelo conceito de maleabilidade no processo de transição da infância para a idade adulta e na apreensão especifica da amizade apresentados no romance / A study of George Eliots Daniel Deronda identifying the concept of malleability as the key idea for understanding the moral ideals in the novel. Discussion of the role malleability plays in the process of transition from childhood to adulthood and in the specific view of friendship presented in the novel

This study explores the marketability of Isak Dinesen's Seven Gothic Tales, published in the US in 1934. The term marketability is used to refer to the book as a potentially desirable object for sale on the market, successfully promoted by the Book-of-the-Month-Club whose members were intent on educating themselves and refining their taste. The set-up and marketing strategies of the Book-of-the-Month-Club are considered in relation to the role of advertising as a discourse teaching social and personal values in a developing consumer culture where identity and personality were represented as never-ending, imperative projects.  The consuming self is an individual freed from the restraints of tradition and communal values, making her free choice of whom to be on an increasingly diverse market, endlessly reinventing her identity. But this self is also a commodity on an increasingly complex and impersonal market where appearance is destiny. A historically contextualized reading of Seven Gothic Tales makes it possible to use the term marketability to refer to the work itself as a literary investigation of the conditions of identity-construction in a culture dominated by market-mediated relationships. In this reading, the Great Depression figures as a moment that reveals the degree to which consumerist ideology and logic had come to determine the possibilities of imagining being and identity, a condition that Seven Gothic Tales both reflects and resists. The effect of globalized transformation of production and consumption were felt in the two places that went into the making of Seven Gothic Tales: the US where it was first published and colonial Kenya where the author lived between 1914 and 1931 and where the book was begun. This study argues that the success of Seven Gothic Tales in the US depended on the way in which Blixen/Dinesen's experience of colonial Kenya was an experience of commercial modernity that reverberated with the experience of the American readers. Central to this argument is the ideal of feudalism as an explicit and decisive element in the creation of colonial Kenya. The aristocratic theme that permeates Seven Gothic Tales must be understood in relation to a colonial socioeconomic context that reinvented the feudal ideal as a marketable commodity at a time when social status and identity had become negotiable on a consumer market.

Traditionally, cryptographic algorithms are designed under the so-called black-box model, which considers adversaries that receive black-box access to the hardware implementation. Although a "black-box" treatment covers a wide range of attacks, it fails to capture reality adequately, as real-world adversaries can exploit physical properties of the implementation, mounting attacks that enable unexpected, non-black-box access, to the components of the cryptographic system. This type of attacks is widely known as physical attacks, and has proven to be a significant threat to the real-world security of cryptographic systems. The present dissertation is (partially) dealing with the problem of protecting cryptographic memory against physical attacks, via the use of non-malleable codes, which is a notion introduced in a preceding work, aiming to provide privacy of the encoded data, in the presence of adversarial faults. In the present thesis we improve the current state-of-the-art on non-malleable codes and we provide practical solutions for protecting real-world cryptographic implementations against physical attacks. Our study is primarily focusing on the following adversarial models: (i) the extensively studied split-state model, which assumes that private memory splits into two parts, and the adversary tampers with each part, independently, and (ii) the model of partial functions, which is introduced by the current thesis, and models adversaries that access arbitrary subsets of codeword locations, with bounded cardinality. Our study is comprehensive, covering one-time and continuous, attacks, while for the case of partial functions, we manage to achieve a stronger notion of security, that we call non-malleability with manipulation detection, that in addition to privacy, it also guarantees integrity of the private data. It should be noted that, our techniques are also useful for the problem of establishing, private, keyless communication, over adversarial communication channels. Besides physical attacks, another important concern related to cryptographic hardware security, is that the hardware fabrication process is assumed to be trusted. In reality though, when aiming to minimize the production costs, or whenever access to leading-edge manufacturing facilities is required, the fabrication process requires the involvement of several, potentially malicious, facilities. Consequently, cryptographic hardware is susceptible to the so-called hardware Trojans, which are hardware components that are maliciously implanted to the original circuitry, having as a purpose to alter the device's functionality, while remaining undetected. Part of the present dissertation, deals with the problem of protecting cryptographic hardware against Trojan injection attacks, by (i) proposing a formal model for assessing the security of cryptographic hardware, whose production has been partially outsourced to a set of untrusted, and possibly malicious, manufacturers, and (ii) by proposing a compiler that transforms any cryptographic circuit, into another, that can be securely outsourced.

This work focuses on scheduling of MPI jobs when executing in shared-memory multiprocessors (SMPs). The objective was to obtain the best performance in response time in multiprogrammed multiprocessors systems using batch systems, assuming all the jobs have the same priority. To achieve that purpose, the benefits of supporting malleability on MPI jobs to reduce fragmentation and consequently improve the performance of the system were studied. The contributions made in this work can be summarized as follows:· Virtual malleability: A mechanism where a job is assigned a dynamic processor partition, where the number of processes is greater than the number of processors. The partition size is modified at runtime, according to external requirements such as the load of the system, by varying the multiprogramming level, making the job contend for resources with itself. In addition to this, a mechanism which decides at runtime if applying local or global process queues to an application depending on the load balancing between processes of it. · A job scheduling policy, that takes decisions such as how many processes to start with and the maximum multiprogramming degree based on the type and number of applications running and queued. Moreover, as soon as a job finishes execution and where there are queued jobs, this algorithm analyzes whether it is better to start execution of another job immediately or just wait until there are more resources available. · A new alternative to backfilling strategies for the problema of window execution time expiring. Virtual malleability is applied to the backfilled job, reducing its partition size but without aborting or suspending it as in traditional backfilling. The evaluation of this thesis has been done using a practical approach. All the proposals were implemented, modifying the three scheduling levels: queuing system, processor scheduler and runtime library. The impact of the contributions were studied under several types of workloads, varying machine utilization, communication and, balance degree of the applications, multiprogramming level, and job size. Results showed that it is possible to offer malleability over MPI jobs. An application obtained better performance when contending for the resources with itself than with other applications, especially in workloads with high machine utilization. Load imbalance was taken into account obtaining better performance if applying the right queue type to each application independently.The job scheduling policy proposed exploited virtual malleability by choosing at the beginning of execution some parameters like the number of processes and maximum multiprogramming level. It performed well under bursty workloads with low to medium machine utilizations. However as the load increases, virtual malleability was not enough. That is because, when the machine is heavily loaded, the jobs, once shrunk are not able to expand, so they must be executed all the time with a partition smaller than the job size, thus degrading performance. Thus, at this point the job scheduling policy concentrated just in moldability.Fragmentation was alleviated also by applying backfilling techniques to the job scheduling algorithm. Virtual malleability showed to be an interesting improvement in the window expiring problem. Backfilled jobs even on a smaller partition, can continue execution reducing memory swapping generated by aborts/suspensions In this way the queueing system is prevented from reinserting the backfilled job in the queue and re-executing it in the future.

Following a head concussion the intracranial pressure increases due to the impact, which cannot be adequately relieved because of the stiffness of the skull. Popular strategies aimed at decompressing the head consist in the administration of osmotic agents and skull removal. The mechanical properties of bone can be affected by the administration of different solutions. If the malleability of skull is influenced by the osmotic agents that are administered to the patient then the pressure and volume in the intracranial cavity can also be modified following the treatment. In this thesis research, we hypothesize that administered osmotic agents can influence the mechanical properties of the skull, which can also impact the volume the cavity can hold and subsequently the pressure in the head. This premise was tested by modifying existing mathematical models compiled through two general MATLAB codes that allow the computation of a non-symbolic differential-algebraic initial value problem. Three main features were changed in comparison to current models: the skull's influence on the pressure and volume modulation was tested (inputs were obtained from skull tested under different solutions); pulsatile flow was accounted for on the creation and movement of cerebrospinal fluid; and the input on the mechanical behavior of the cranial vessels was accounted for through previously published continuum-mechanics vessel-behavior models. To complete the model, materials and mechanical properties were obtained through laboratory experiments as well as data collection from existing literature. From our bone test we were able to conclude that there are different factors that affect the mechanical properties of bone in various degrees. There is a mild statistical correlation (p-value 0.05) between the mechanical properties of bone obtained from different regions of the skull samples (2-14mm) and the DPBS and hDPBS solutions. Additionally there is a strong statistical difference (p-value 0.05) between the mechanical properties obtained from cross head speed (0.02, 0.002, and 0.004 (mm/s)) and solution variation (DI, DPBS and hDPBS). Finally, we were able to see that there seems to be a correlation between the mechanical properties of bone, the solution treatments and hypertension; although more test need to be developed to affirm this premise since our results are preliminary.

Atualmente, adaptabilidade é uma característica desejada em aplicações paralelas. Por exemplo, o crescente número de usuários competindo por recursos em arquiteturas paralelas gera mudanças constantes no conjunto de processadores disponíveis. Aplicações adaptativas são capazes de executar usando um conjunto volátil de processadores, oferecendo urna melhor utilização dos recursos. Este comportamento adaptativo é conhecido corno maleabilidade. Outro exemplo vem da constante evolução das arquiteturas multi-core, as quais aumentam o número de cores em seus chips a cada nova geração. Adaptabilidade é a chave para permitir que os programas paralelos sejam portáveis de uma máquina a outra. Assim. os programas paralelos são capazes de adaptar a extração do paralelismo de acordo com o grau de paralelismo específico da arquitetura alvo. Este comportamento pode ser visto como um caso particular de evolutividade. Nesse sentido, esta tese está focada em: (i) maleabilidade para adaptar a execução das aplicações paralelas às mudanças na disponibilidade dos processadores; e (ii) evolutividade para adaptar a extração do paralelismo de acordo com propriedades da arquitetura e dos dados de entrada. Portanto, a questão remanescente é "Como prover e suportar aplicações adaptativas?". Esta tese visa responder tal questão com base no MPI (Message-Passing Interface), o qual é a API paralela padrão para HPC em ambientes distribuídos. Nosso trabalho baseia-se nas características do MPI-2 que permitem criar processos em tempo de execução, dando alguma flexibilidade às aplicações MPI. Aplicações MPI maleáveis usam a criação dinâmica de processos para expandir-se nas ações de crescimento (para usar processadores extras). As ações de diminuição (para liberar processadores) finalizam os processos MPI que executam nos processadores requeridos, preservando os dados da aplicação. Note que as aplicações maleáveis requerem suporte do ambiente de execução, uma vez que precisam ser notificadas sobre a disponibilidade dos processadores. Aplicações MPI evolutivas seguem o paradigma do paralelismo de tarefas explícitas para permitir adaptação em tempo de execução. Assim, a criação dinâmica de processos é usada para extrair o paralelismo, ou seja, para criar novas tarefas MPI sob demanda. Para prover tais aplicações nós definimos tarefas MPI abstratas, implementamos a sincronização entre elas através da troca de mensagens, e propusemos uma abordagem para ajustar a granularidade das tarefas MPI, visando eficiência em ambientes distribuídos. Os resultados experimentais validaram nossa hipótese de que aplicações adaptativas podem ser providas usando características do MPI-2. Adicionalmente, esta tese identificou os requisitos rio nível do ambiente de execução para suportá-las em clusters. Portanto, as aplicações MPI maleáveis melhoraram a utilização de recursos de clusters; e as aplicações de tarefas explícitas adaptaram a extração do paralelismo de acordo com a arquitetura alvo. mostrando que este paradigma também é eficiente em ambientes distribuídos. / Currently, adaptability is a desired feature in parallel applications. For instante, the increasingly number of user competing for resources of the parallel architectures causes dynamic changes in the set of available processors. Adaptive applications are able to execute using a set of volatile processors, providing better resource utilization. This adaptive behavior is known as malleability. Another example comes from the constant evolution of the multi-core architectures, which increases the number of cores to each new generation of chips. Adaptability is the key to allow parallel programs portability from one multi-core machine to another. Thus, parallel programs can adapt the unfolding of the parallelism to the specific degree of parallelism of the target architecture. This adaptive behavior can be seen as a particular case of evolutivity. In this sense, this thesis is focused on: (i) malleability to adapt the execution of parallel applications as changes in processors availability; and (ii) evolutivity to adapt the unfolding of the parallelism at runtime as the architecture and input data properties. Thus, the open issue is "How to provide and support adaptive applications?". This thesis aims to answer this question taking into account the MPI (Message-Passing Interface), which is the standard parallel API for HPC in distributed-memory environments. Our work is based on MPI-2 features that allow spawning processes at runtime. adding some fiexibility to the MPI applications. Malleable MPI applications use dynamic process creation to expand themselves in growth action (to use further processors). The shrinkage actions (to release processors) end the execution of the MPI processes on the required processors in such a way that the application's data are preserved. Notice that malleable applications require a runtime environment support to execute, once they must be notified about the processors availability. Evolving MPI applications follow the explicit task parallelism paradigm to allow their runtime adaptation. Thus, dynamic process creation is used to unfold the parallelism, i.e., to create new MPI tasks on demand. To provide these applications we defined the abstract MPI tasks, implemented the synchronization among these tasks through message exchanges, and proposed an approach to adjust MPI tasks granularity aiming at efficiency in distributed-memory environments. Experimental results validated our hypothesis that adaptive applications can be provided using the MPI-2 features. Additionally, this thesis identifies the requirements to support these applications in cluster environments. Thus, malleable MPI applications were able to improve the cluster utilization; and the explicit task ones were able to adapt the unfolding of the parallelism to the target architecture, showing that this programming paradigm can be efficient also in distributed-memory contexts.

Atualmente, adaptabilidade é uma característica desejada em aplicações paralelas. Por exemplo, o crescente número de usuários competindo por recursos em arquiteturas paralelas gera mudanças constantes no conjunto de processadores disponíveis. Aplicações adaptativas são capazes de executar usando um conjunto volátil de processadores, oferecendo urna melhor utilização dos recursos. Este comportamento adaptativo é conhecido corno maleabilidade. Outro exemplo vem da constante evolução das arquiteturas multi-core, as quais aumentam o número de cores em seus chips a cada nova geração. Adaptabilidade é a chave para permitir que os programas paralelos sejam portáveis de uma máquina a outra. Assim. os programas paralelos são capazes de adaptar a extração do paralelismo de acordo com o grau de paralelismo específico da arquitetura alvo. Este comportamento pode ser visto como um caso particular de evolutividade. Nesse sentido, esta tese está focada em: (i) maleabilidade para adaptar a execução das aplicações paralelas às mudanças na disponibilidade dos processadores; e (ii) evolutividade para adaptar a extração do paralelismo de acordo com propriedades da arquitetura e dos dados de entrada. Portanto, a questão remanescente é "Como prover e suportar aplicações adaptativas?". Esta tese visa responder tal questão com base no MPI (Message-Passing Interface), o qual é a API paralela padrão para HPC em ambientes distribuídos. Nosso trabalho baseia-se nas características do MPI-2 que permitem criar processos em tempo de execução, dando alguma flexibilidade às aplicações MPI. Aplicações MPI maleáveis usam a criação dinâmica de processos para expandir-se nas ações de crescimento (para usar processadores extras). As ações de diminuição (para liberar processadores) finalizam os processos MPI que executam nos processadores requeridos, preservando os dados da aplicação. Note que as aplicações maleáveis requerem suporte do ambiente de execução, uma vez que precisam ser notificadas sobre a disponibilidade dos processadores. Aplicações MPI evolutivas seguem o paradigma do paralelismo de tarefas explícitas para permitir adaptação em tempo de execução. Assim, a criação dinâmica de processos é usada para extrair o paralelismo, ou seja, para criar novas tarefas MPI sob demanda. Para prover tais aplicações nós definimos tarefas MPI abstratas, implementamos a sincronização entre elas através da troca de mensagens, e propusemos uma abordagem para ajustar a granularidade das tarefas MPI, visando eficiência em ambientes distribuídos. Os resultados experimentais validaram nossa hipótese de que aplicações adaptativas podem ser providas usando características do MPI-2. Adicionalmente, esta tese identificou os requisitos rio nível do ambiente de execução para suportá-las em clusters. Portanto, as aplicações MPI maleáveis melhoraram a utilização de recursos de clusters; e as aplicações de tarefas explícitas adaptaram a extração do paralelismo de acordo com a arquitetura alvo. mostrando que este paradigma também é eficiente em ambientes distribuídos. / Currently, adaptability is a desired feature in parallel applications. For instante, the increasingly number of user competing for resources of the parallel architectures causes dynamic changes in the set of available processors. Adaptive applications are able to execute using a set of volatile processors, providing better resource utilization. This adaptive behavior is known as malleability. Another example comes from the constant evolution of the multi-core architectures, which increases the number of cores to each new generation of chips. Adaptability is the key to allow parallel programs portability from one multi-core machine to another. Thus, parallel programs can adapt the unfolding of the parallelism to the specific degree of parallelism of the target architecture. This adaptive behavior can be seen as a particular case of evolutivity. In this sense, this thesis is focused on: (i) malleability to adapt the execution of parallel applications as changes in processors availability; and (ii) evolutivity to adapt the unfolding of the parallelism at runtime as the architecture and input data properties. Thus, the open issue is "How to provide and support adaptive applications?". This thesis aims to answer this question taking into account the MPI (Message-Passing Interface), which is the standard parallel API for HPC in distributed-memory environments. Our work is based on MPI-2 features that allow spawning processes at runtime. adding some fiexibility to the MPI applications. Malleable MPI applications use dynamic process creation to expand themselves in growth action (to use further processors). The shrinkage actions (to release processors) end the execution of the MPI processes on the required processors in such a way that the application's data are preserved. Notice that malleable applications require a runtime environment support to execute, once they must be notified about the processors availability. Evolving MPI applications follow the explicit task parallelism paradigm to allow their runtime adaptation. Thus, dynamic process creation is used to unfold the parallelism, i.e., to create new MPI tasks on demand. To provide these applications we defined the abstract MPI tasks, implemented the synchronization among these tasks through message exchanges, and proposed an approach to adjust MPI tasks granularity aiming at efficiency in distributed-memory environments. Experimental results validated our hypothesis that adaptive applications can be provided using the MPI-2 features. Additionally, this thesis identifies the requirements to support these applications in cluster environments. Thus, malleable MPI applications were able to improve the cluster utilization; and the explicit task ones were able to adapt the unfolding of the parallelism to the target architecture, showing that this programming paradigm can be efficient also in distributed-memory contexts.

Atualmente, adaptabilidade é uma característica desejada em aplicações paralelas. Por exemplo, o crescente número de usuários competindo por recursos em arquiteturas paralelas gera mudanças constantes no conjunto de processadores disponíveis. Aplicações adaptativas são capazes de executar usando um conjunto volátil de processadores, oferecendo urna melhor utilização dos recursos. Este comportamento adaptativo é conhecido corno maleabilidade. Outro exemplo vem da constante evolução das arquiteturas multi-core, as quais aumentam o número de cores em seus chips a cada nova geração. Adaptabilidade é a chave para permitir que os programas paralelos sejam portáveis de uma máquina a outra. Assim. os programas paralelos são capazes de adaptar a extração do paralelismo de acordo com o grau de paralelismo específico da arquitetura alvo. Este comportamento pode ser visto como um caso particular de evolutividade. Nesse sentido, esta tese está focada em: (i) maleabilidade para adaptar a execução das aplicações paralelas às mudanças na disponibilidade dos processadores; e (ii) evolutividade para adaptar a extração do paralelismo de acordo com propriedades da arquitetura e dos dados de entrada. Portanto, a questão remanescente é "Como prover e suportar aplicações adaptativas?". Esta tese visa responder tal questão com base no MPI (Message-Passing Interface), o qual é a API paralela padrão para HPC em ambientes distribuídos. Nosso trabalho baseia-se nas características do MPI-2 que permitem criar processos em tempo de execução, dando alguma flexibilidade às aplicações MPI. Aplicações MPI maleáveis usam a criação dinâmica de processos para expandir-se nas ações de crescimento (para usar processadores extras). As ações de diminuição (para liberar processadores) finalizam os processos MPI que executam nos processadores requeridos, preservando os dados da aplicação. Note que as aplicações maleáveis requerem suporte do ambiente de execução, uma vez que precisam ser notificadas sobre a disponibilidade dos processadores. Aplicações MPI evolutivas seguem o paradigma do paralelismo de tarefas explícitas para permitir adaptação em tempo de execução. Assim, a criação dinâmica de processos é usada para extrair o paralelismo, ou seja, para criar novas tarefas MPI sob demanda. Para prover tais aplicações nós definimos tarefas MPI abstratas, implementamos a sincronização entre elas através da troca de mensagens, e propusemos uma abordagem para ajustar a granularidade das tarefas MPI, visando eficiência em ambientes distribuídos. Os resultados experimentais validaram nossa hipótese de que aplicações adaptativas podem ser providas usando características do MPI-2. Adicionalmente, esta tese identificou os requisitos rio nível do ambiente de execução para suportá-las em clusters. Portanto, as aplicações MPI maleáveis melhoraram a utilização de recursos de clusters; e as aplicações de tarefas explícitas adaptaram a extração do paralelismo de acordo com a arquitetura alvo. mostrando que este paradigma também é eficiente em ambientes distribuídos. / Currently, adaptability is a desired feature in parallel applications. For instante, the increasingly number of user competing for resources of the parallel architectures causes dynamic changes in the set of available processors. Adaptive applications are able to execute using a set of volatile processors, providing better resource utilization. This adaptive behavior is known as malleability. Another example comes from the constant evolution of the multi-core architectures, which increases the number of cores to each new generation of chips. Adaptability is the key to allow parallel programs portability from one multi-core machine to another. Thus, parallel programs can adapt the unfolding of the parallelism to the specific degree of parallelism of the target architecture. This adaptive behavior can be seen as a particular case of evolutivity. In this sense, this thesis is focused on: (i) malleability to adapt the execution of parallel applications as changes in processors availability; and (ii) evolutivity to adapt the unfolding of the parallelism at runtime as the architecture and input data properties. Thus, the open issue is "How to provide and support adaptive applications?". This thesis aims to answer this question taking into account the MPI (Message-Passing Interface), which is the standard parallel API for HPC in distributed-memory environments. Our work is based on MPI-2 features that allow spawning processes at runtime. adding some fiexibility to the MPI applications. Malleable MPI applications use dynamic process creation to expand themselves in growth action (to use further processors). The shrinkage actions (to release processors) end the execution of the MPI processes on the required processors in such a way that the application's data are preserved. Notice that malleable applications require a runtime environment support to execute, once they must be notified about the processors availability. Evolving MPI applications follow the explicit task parallelism paradigm to allow their runtime adaptation. Thus, dynamic process creation is used to unfold the parallelism, i.e., to create new MPI tasks on demand. To provide these applications we defined the abstract MPI tasks, implemented the synchronization among these tasks through message exchanges, and proposed an approach to adjust MPI tasks granularity aiming at efficiency in distributed-memory environments. Experimental results validated our hypothesis that adaptive applications can be provided using the MPI-2 features. Additionally, this thesis identifies the requirements to support these applications in cluster environments. Thus, malleable MPI applications were able to improve the cluster utilization; and the explicit task ones were able to adapt the unfolding of the parallelism to the target architecture, showing that this programming paradigm can be efficient also in distributed-memory contexts.