Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1981. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND AERO / Bibliography: p. 131-132. / by Louis Howard Knotts. / M.S.

O presente estudo teve como objetivo desenvolver um modelo de habilidades técnicas do ataque da posição quatro e por meio do modelo, analisar o comportamento do ataque da posição quatro na categoria infanto-juvenil masculina. Para o primeiro objetivo, utilizou-se do método delphi, entrevistando-se em dois momentos distintos (1ª e 2ª etapas) 14 treinadores das seleções brasileiras de voleibol masculina e feminina. Enquanto que na primeira etapa foi delineada a estrutura do modelo, na segunda, foi possível elaborar o modelo propriamente dito a partir do nível esperado de consenso. Os resultados demonstraram que, para as onze situações de bloqueio, cento e setenta e duas habilidades técnicas foram relacionadas pelos treinadores, entre as quais, somente quatro (SBT1-I, SBT1-J, SBT3-A e SBT3-S) não alcançaram o critério de consenso estabelecido (média, moda, mediana igual ou superior a 4.0 e desvio padrão igual ou inferior a 0,65). Para o segundo objetivo, foram observados doze jogos em campeonatos mundiais dos anos 2005 e 2007, nos quais foram analisados valores de freqüência de ocorrência e eficácia. Os resultados mostraram maiores ocorrências nas situações de bloqueios duplos seguidas dos bloqueios simples e triplos. Quanto às habilidades técnicas, a corrida de aproximação em diagonal foi a mais utilizada pelos atacantes com opção de ataque direto. As habilidades com ataque explorando o bloqueio ocorreram com maior freqüência frente aos bloqueios duplos e triplos compactos. A análise de correlação de Spearman detectou baixo nível de associação entre freqüência de ocorrência e eficácia. Contudo, a análise de regressão logística (binária e multinomial) entre as habilidades mais freqüentes permitiu verificar que a SBD1-A foi a situação/habilidade que mais ocorreu, no entanto, com menores chances de sucesso entre a maioria das situações/habilidades investigadas. As habilidades técnicas empregadas nas situações de bloqueio simples obtiveram maiores chances de sucesso que as habilidades utilizadas nos bloqueios duplos. Os resultados destacaram o aspecto situacional do ataque, o qual revelou necessidade de aplicação de habilidades técnicas específicas em determinadas estruturas de bloqueio para se obter o sucesso / The objective of this study was to develop a model for attack technical skills in zone four and to analyze the performance of young players through this model. In the first case, through the delphi method and in two distinct moments (1st and 2nd phases), fourteen coaches of the Brazilian male and female teams were interviewed. The structure of the model was designed in the first phase and, by means of consensus, the model itself was eventually designed in the second phase. Results evidenced that 170 attack technical skills were reported by the coaches in eleven block situations, and only four (SBT1-I, SBT1-J, SBT3-A e SBT3-S) did not reach the consensus level (mean, mode, median equal or above 4.0 and standard deviation 0,65). In the second case, twelve games were analyzed during the world championships in years 2005 and 2007 in the frequency and efficacy of actions. The results from the analysis of attack performances from zone four during the world championships showed a larger number in double blocks followed by simple and triple blocks. As for technical skills, the type of run with diagonal approach was the most used by attack players with the option of direct attack. Techniques where attack explores blocking were most common in compact double and triple blocks. The Spearman correlation analysis showed no relation between frequency and efficacy. However, a logistic regression analysis (binary and multinomial) between the most frequent techniques evidenced that SBD1-A block/skill situation was the most frequent but least likely to success. Technical skills in simple block situations were more likely to be successful than those in double blocks. The results also highlighted the situational aspect of attack that requires specific technical skills for certain block structures to be successful

This dissertation examines the reasons why states want to acquire nonconventional weapons and analyzes interconnections between decisions on nuclear weapons (NW) on the one hand and chemical/biological weapons (CBW) on the other. Much of the literature on non-conventional weapons has tended to focus either on nuclear weapons or on CBW, with CBW often portrayed as the “poor man's nuclear bomb.” While there is some truth in this, the interconnections between decisions to develop NW and decisions to develop CBW are more numerous, more varied and more nuanced. The dissertation examines non-conventional armament processes in the United Kingdom and Iraq. Using two disparate cases provides the analysis with a comprehensive data set, the lessons from which have formed the basis of the analysis. Having nuclear, biological and chemical (NBC) weapons for the purpose of use is not always a state's ultimate goal and factors as wide-ranging as national prestige and the maintenance of international relationships are important in determining why some states decide to pursue NBC weapons. The case study findings have been synthesized into four key areas in which NBC linkages are particularly significant: strategic issues and strategic cultures; political considerations; economics and finances; and future challenges. The key finding is that there are interconnections that show how NW and CBW influence each other. For example, both the UK and Iraq showed that if nuclear weapons were not available, interest in CBW would increase. Conversely, possession of nuclear weapons does not necessarily rule out interest in acquiring CBW armament. Non-conventional weapons present a significant challenge to the maintenance of international peace and security. As this dissertation demonstrates, NBC weapons are linked on many levels and it is important to understand how CBW can and do influence policy on nuclear weapons and vice versa.

O QC-MDPC McEliece foi considerado um dos mais promissores esquemas criptográficos de chave pública que oferecem segurança contra ataques por computadores quânticos. O tamanho das chaves públicas do QC-MDPC McEliece é competitivo com o das chaves do RSA, e o esquema tem uma redução de segurança aparentemente forte. Por três anos, o esquema não sofreu ataques críticos, até que na Asiacrypt de 2016 Guo, Johansson, e Stankovski mostraram um ataque de reação contra o QC-MDPC McEliece que explora um aspecto não considerado em sua redução de segurança: a probabilidade de o algoritmo de decriptação falhar é menor quando a chave secreta e o vetor usado para encriptar a mensagem compartilham certas propriedades, chamadas de espectros. Dessa forma, um atacante pode, ao detectar falhas de decriptação, obter informação sobre o espectro, que será usada para reconstruir a chave secreta. Guo et al. apresentaram um algoritmo para a reconstrução da chave a partir do espectro recuperado, para o qual é possível apontar três problemas. O primeiro é que seu algoritmo não é eficiente quando o espectro da chave não foi recuperado quase completamente, o que resulta em o atacante ter que enviar um grande número de testes de decriptação à portadora da chave secreta. O segundo problema é que o desempenho de seu algoritmo não escala bem para níveis de segurança mais altos. O terceiro e último problema é que, por ser baseado numa busca em profundidade, seu algoritmo não pode ser paralelizado trivialmente. Para aumentar a eficiência do ataque, dois novos algoritmos de reconstrução são propostos neste trabalho. Estes algoritmos são mais eficientes, usam menos informação sobre a chave secreta, e podem ser paralelizados trivialmente. O primeiro algoritmo é probabilístico e tem complexidade assintótica ligeiramente melhor do que a do original. Entretanto, o desempenho do algoritmo probabilístico piora rapidamente, embora mais lentamente do que o algoritmo de Guo et al., conforme a quantidade de informação sobre o espectro diminui. O segundo algoritmo explora uma relação linear entre os blocos da chave secreta. Este é mais eficiente, tanto assintoticamente quanto na prática, que os dois outros algoritmos, e é eficiente mesmo com 50% menos informação sobre o espectro do que o necessário para o algoritmo original. Isso permite que o atacante encontre a chave secreta fazendo apenas em torno de 20% do número de testes necessários pelo algoritmo de Guo\'s et al., considerando-se o nível de segurança de 80 bits. O desempenho de ambos os algoritmos são analisados e comparados com o do algoritmo original, e as análises são feitas tanto para a complexidade teórica quanto para o desempenho na prática, considerando a implementação dos algoritmos em linguagem C. / The QC-MDPC McEliece scheme was considered one of the most promising public key encryption schemes for efficient post-quantum secure encryption. As a variant of the McEliece scheme, it is based on the syndrome decoding problem, an NP-hard problem from Coding Theory. The key sizes are competitive with the ones of the widely used RSA cryptosystem, and it came with an apparently strong security reduction. For three years, the scheme has not suffered major threats, until the end of 2016, when Guo, Johansson, and Stankovski presented at Asiacrypt a reaction attack on the QC-MDPC that exploits one aspect that was not considered in the security reduction: the probability of a decoding failure to occur is lower when the secret key and the error used for encryption share certain properties, which they called spectrums. By detecting decoding failures, the attacker can obtain information on the spectrum of the secret key and then use this information to reconstruct the key. Guo et al. presented an algorithm for key reconstruction for which we can point three weaknesses. The first one is that it cannot deal efficiently with partial information on the spectrum of the secret key, resulting in the attacker having to send a great number of decoding trials. The second one is that it does not scale well for higher security levels. The third one is that the algorithm, which is based on a depth-first search, cannot be trivially parallelized. To improve the efficiency of the attack, we propose two different key reconstruction algorithms that are more efficient, use less information on the secret key, and can be trivially parallelized. The first algorithm, which is a simple probabilistic extension of Guo\'s et al. algorithm, is more efficient and runs increasingly faster, for higher security levels, than the original one. However, for security levels higher than 80 bits, the probabilistic algorithm cannot run efficiently without too much information on the spectrum of the secret key, even though it needs less information than the original algorithm. The second algorithm is based on a linear relation between the blocks of the secret key. It can run efficiently with around 50% less information than needed by Guo\'s et al. key reconstruction algorithm. This makes it possible for an attacker to recover the secret key sending approximately 20% of the of the number of decoding trials needed by Guo\'s et al. algorithm, for the security level of 80 bits. The performance of each presented algorithm is analyzed and compared with that of the original one. The analysis are made theoretically, considering a probabilistic analysis of the algorithms, and in practice, considering the corresponding implementations in C language.

Thesis (MPH) --University of Limpopo, 2007. / Aim of the study: To determine knowledge of CPR and heart attack or cardiac arrest signs and symptoms among university students. Study Design: A questionnaire based descriptive, cross – sectional study. Setting: University of Limpopo – Turfloop Campus in Limpopo Province of South Africa. Subjects: A total sample of 400 students participated in the study. The sample was selected randomly using simple random sampling techniques. Outcome measures: The faculty, age, gender and level of study were determined as well as the knowledge each student has on signs and symptoms of impending heart attack and CPR.Results: Of the 400 students only 26% (n=104) knew the signs and symptoms of an impending heart attack as well as out of hospital management of heart attack by performing CPR. There were differences between and within faculties, age groups, gender and level of study. Based on the Bonferroni test the student from faculty of Sciences, Health and Agriculture are more likely (p-value 0017) to know when to perform CPR compared to students from other faculties. Level of study is not associated (p-value 0128) with how much the students know about the timing and indications of CPR. Overall female students performed worse with 79% (n=123) responding incorrectly to the questions compared to 69% (n=169) males. Conclusion: Based on the results of this study it safely can be concluded that the students’ knowledge of signs and symptoms of an impending heart attack and CPR procedure is poor. It is therefore important for the university as a center of teaching and learning to consider including as part of university curriculum, basic life support and first aid courses which include CPR. The inclusion of basic life support and first aid in university curriculum will prepare students to be able to effectively manage out of hospital heart attack and reduce mortality resulting from the latter. The findings of this study might to a certain extent be reflecting what the public’s knowledge on the subject is, hence the need for the policy makers to take serious note of the findings when public health promotion programmes are developed.

The objective of this investigation was to assess the influence of the SO3 content on the durability and strength of portland cement. Four portland cements were used in this study. The cements had a variable tricalcium silicate, tricalcium aluminate, and alkali contents, as well as differences in the amount and form of calcium sulfates. The SO3 content of the cements was increased by replacing part of the cement by gypsum according to ASTM C 452-95. Mortar bars and cubes were prepared for the as-received as well as for the cements with an SO3 content of 3.0% and 3.6%. The durability of the as-received and doped cements was determined by measuring the length change of the mortar bars that were exposed to sodium sulfate environment. The compressive strength of the mortar cubes prepared for the same mixes was measured at different ages for sets of cubes cured both in sodium sulfate solution and in saturated lime solution. It was concluded at the end of this study that there is an optimum SO3 content for the lowest expansion that is different from that determined for the highest compressive strength. Optimum values also differed from one cement to another and from one age to another for the same cement. The results also indicate the dependence of SO3 content on tricalcium aluminate and alkali content of cements. In addition, for all cements examined in this study with alkali content of less than 0.60%, increasing the SO3 content above 3.0% had negative effects on durability assessed by strength or expansion measurements. For the cement with highest alkali and tricalcium aluminate content, increasing the SO3 content from 3.0% to 3.6% delayed the onset of strength drop; however, at 360 days the strength drop experienced by both doping levels was the same.

In an effort to make structures more sustainable and durable, supplementary cementitious materials are often used to replace cement. Ground granulated blast furnace slag, for instance, is an industrial by-product of iron refinement and is frequently used in concrete mixture design to not only reduce cost, but also increase later-age strength as well as durability. However, published literature indicates that slags with a high alumina content may have a detrimental effect when concrete is exposed to a sulfate environment. ASTM standard C989 does not suggest any information or guidelines regarding using slags with an alumina content between 11-18%. Therefore, the objective of this study was to fill in the gap of this standard by studying slags of variable alumina content as high as 16 percent. This study presents data collected for compressive strengths of mortar cubes exposed to lime and 5 percent sodium sulfate solution at ages of 7, 28, 91, and 182 days from the date of mixing as well as expansion data for mortar bar specimens exposed to 5 percent sodium sulfate solution up to 120 days. Slag replacement levels used here were 0, 30, 50, and 70%. Mortar bar specimens showing deterioration were analyzed using x-ray diffraction coupled with Rietveld refinement to assess the mechanism of deterioration. Cubes were stored in lime and sulfate solutions abiding by ASTM C1012 in order to analyze the resistance to sulfate attack. Sulfate resistance was measured in terms of decalcification of the CSH gel as well as expansion. The results suggest using high alumina slags at a low percentage adversely affects sulfate resistance since the acquired strength at 182 days fell below that of 28 day strength, which is often used in the industry as the parameter which constitutes whether a mixture is adequate. It was also seen that increasing alumina content of the slag resulted in increased expansion. X-ray diffraction analysis indicates that the mechanism of deterioration, of the control as well as the blended mortar, is due to secondary gypsum and secondary ettringite formation. Therefore, it is recommended that slags having a high alumina content should be further analyzed in laboratory tests to examine their performance especially if concrete will be subjected to a sulfate environment during its service life.

[pt] Este estudo investiga o papel do hipocampo no comportamento de defesa condicionado e incondicionado examinando o efeito de lesões eletrolíticas pré-treino no hipocampo dorsal e ventral de ratos expostos a dois tipos de estímulos aversivos: estimulação elétrica da matéria cinzenta periaquedutal dorsal e choque nas patas. A lesão na parte dorsal e ventral diminuiu significativamente o comportamento defensivo condicionado. No comportamento defensivo incondicionado, a lesão ventral alterou significativamente o congelamento pré-fuga e a fuga. Os resultados sugerem um papel específico da parte dorsal e ventral do hipocampo na modulação de defesa através da utilização do modelo animal de ataque de pânico e TAG. / [en] This study investigates the role of the hippocampus in both unconditioned and conditioned defense behavior by examining the effects of pre-training electrolytic lesions to the dorsal and ventral hippocampus in male rats exposed to two types of threat stimuli: electrical stimulation of the DPAG and footshock. Our results indicate that ventral and dorsal lesions significantly attenuated conditioned defensive behavior. During unconditioned trials, ventral hippocampal lesion altered threshold needed for escape and pre-escape freezing. These results suggest a specific role of the ventral and dorsal hippocampus in modulating GAD and panic-attack like behaviors in certain animal model of defense.

The adoption of health behaviours is essential if coronary heart disease patients are to optimise their chance of survival and reduce the likelihood of recurrent coronary events. However, this behavioural change may not ensue following an acute myocardial infarction(AMI). This study on first AMI subjects sought firstly to examine the psychometric properties of five scaled instruments used for assessing health behaviours. Secondly, the study assessed the prevalence of health-enhancing behaviours at the time of the first AMI and 6 months after this event.Thirdly, the magnitude of health behavioural change was then examined. Fourthly, sociodemographic, clinical and psychosocial predictors of health-enhancing behaviours were explored.These health-enhancing behaviours included non-smoking behaviours, normal body mass index (BMI), adequate physical activity, medication adherence and low dietary fat intake. Finally, the study examined relationships between sociodemographic , psychosocial and modifiable lifestyle factors, based on Antonovsky's hypothesis on sense of coherence(SOC), stress and adaptive coping. The study highlights that some modifiable risk factors, for example, being overweight or obese and physical inactivity were more resistant to change following an AMI.This finding, and the relationship between stress and increased dietary fat suggest a need for individualised programs to support the specific needs of AMI patients to change their modifiable cardiac risk factors. / Doctor of Philosophy (PhD)(Health)

<p>Syftet med studien är att undersöka hur två verklighetsbaserade Hollywoodfilmer, Pearl Harbor och World Trade Center, framställer det amerikanska folket samt dess fiender när landet blir attackerat.</p><p>Vår studie är baserad på en kvalitativ kritisk diskursanalys förankrad i hermeneutiken, Vi väljer ut två filmer som vi sedan granskar och analyserar.</p><p>Analysen visar att trots filmerna skiljer sig i handling och när de utspelar sig, så har de många gemensamma faktorer. Det framstår som att USA blir oskyldigt attackerat eftersom det inte redogjorts i filmerna några bakomliggande faktorer till vad som hänt. </p><p>Genom symboler, handlingar, musik och tal speglas en påtaglig amerikansk patriotism i båda filmerna, det amerikanska folket framställs som hjältar, både uniformsbeklädda och privatpersoner. Fienden är en anonym makt som publiken aldrig får chans att identifiera sig med och framställs som hjärtlös och kall genom musik, färger och bildberättande.</p>