Sunk cost accounting refers to the empirical finding that individuals tend to let their decisions be influenced by costs made at an earlier time in such a way that they are more risk seeking than they would be had they not incurred these costs. Such behaviour violates the axioms of economic theory which states individuals should only consider incremental costs and benefits when executing investments. This dissertation is concerned whether the pervasive sunk cost phenomenon extends to corporate acquisitions and financial markets. 122 students from the University of St Andrews participated in three experiments exploring the use of sunk costs in interactive negotiation contexts and financial markets. Experiment I elucidates that subjects value the sunk cost issue higher than other issues in a multi-issue negotiation. Experiment II illustrates that bidders are influenced by the sunk costs of competing bidders in a first price, sealed-bid, common-value auction. In financial markets their exists an analogous concept to sunk cost accounting known as the disposition effect. This explains the tendency of investors to sell “winning” stocks and hold “losing” stocks. Experiment III demonstrates that trading strategies in an experimental equity market are influenced by a pre-trading brokerage cost. Not only are subjects influenced in the direction that reduces the disposition effect but also trading is diminished. Without the brokerage cost there was a significant disposition effect.

En dépit de moyens importants consacrés à la lutte, certains feux de forêt, en Europe méditerranéenne, en Australie ou en Amérique du Nord, parcourent de grandes surfaces et développent des comportements violents qui piègent les pompiers. L’étude de rapports internes aux services d’incendie révèle ici les conditions météorologiques et topographiques dans lesquelles se produisent ces feux dangereux. En France, alors que le vent violent est le principal contributeur des feux les plus grands et les plus dangereux, les températures élevées mènent à un autre type d’incendies violents qui se propagent rapidement. En Australie, les pompiers sont souvent piégés par une bascule brutale de la direction du vent mais aussi par des vents forts en terrain accidenté. Au-delà des disparités intercontinentales, la recherche des comportements dynamiques de feu impliqués dans plus de 100 accidents de pompiers à travers le monde amène à distinguer trois types d’incendie. Lors des feux topographiques, en zone de montagne, les accidents sont généralement causés par l’attachement de la flamme sur des pentes supérieures à 20°. Lors des feux guidés par le vent, les zones les plus propices aux accidents sont les pentes déventées où des effets de vortex peuvent se produire. Enfin, lors des feux convectifs, les plus violents, les accidents peuvent se produire loin de toute configuration dangereuse. Pour tenir compte de ces résultats et améliorer leur sécurité, les pompiers doivent adapter leur formation et de développer des compétences d’analyste du feu. Ces experts intègreront les retours d’expérience des incendies passés pour proposer les stratégies de lutte les plus efficaces et sécurisées. / Despite the large expenditure that is dedicated to forest fire suppression in Euro-Mediterranean countries, Australia and North-America, firefighters still face large and severe fire events which eventually entrap them. Investigation of Fire Services’ internal reports addresses here the weather and terrain leading to these dangerous fires. In France, strong wind is the main driver of the largest fires and of the fires that entrap firefighters. However, high temperature is also a key contributor as it influences violent fires with high rates of surface spread. In Australia, a lot of firefighters’ entrapments are due to shifts in wind direction, but others are associated to strong winds in rugged terrain. Whatever the regional specificities, more than 100 firefighters’ entrapments across the world were investigated to find the contribution of dynamic fire behaviors in these entrapments. The results return three different types of fires. During topography-influenced fires, in mountainous area, almost all the entrapments happen on slopes steeper than 20°, prone to flame attachment. During wind-driven fires, leeward slopes prone to vorticity-driven lateral fire spread are the most prominent configurations associated with entrapments. Finally, during convective fires, which are the most violent, entrapments can happen far away from any dangerous configuration. Firefighters should adjust their training courses and promote fire behavior analysts (FBAN) capabilities to benefit from the results of this work and improve their safety. FBAN may consider feedbacks from previous fires to suggest the most efficient and secure firefighting strategies and locations.

In the future the demand for ethanol is expected to increase greatly due to the rising energy requirements in the world. Lignocellulosic materials are a suitable and potentially cheap feedstock for sustainable production of fuel ethanol, since vast quantities of agricultural and forest residues are available in many countries. However, there are several problems involved in the utilization of lignocellulosic raw materials as sugar source. The most common way of releasing the simple sugars in the material is by dilute acid hydrolysis. This procedure is relatively simple and cheap, but in addition to the sugars it creates inhibitory compounds. These inhibitors make it very hard for the yeast to ferment the hydrolyzate and detoxification is often necessary. One way to overcome this problem is to encapsulate the yeast. Encapsulation is an attractive method since it improves the cells stability and inhibitor tolerance, increases the biomass amount inside the reactor, and decreases the cost of cell recovery, recycling and downstream processing. However, the method does not yet permit long-term cultivation since the capsules used so far are not robust enough. Therefore more studies have to be conducted in order to find methods which produce mechanically robust capsules. The main goal of this paper is to find a suitable method to produce robust capsules using different concentration of the chemicals at different pH and also implementing some modifications such as addition of cross-linkers in preparation procedure. In this paper comparison of three different encapsulation techniques were studied based on the mechanical robustness of the capsules. The three different techniques were calcium mineralized alginate-chitosan capsules, alginate capsules coated with 2% chitosan (2% AC) and genipin crosslinked alginate-chitosan (GCAC) capsules. The results indicate that GCAC capsules are most robust and were good enough for prolonged use since most of the capsules were not deformed in mechanical strength test. There were slight differences in the diameter and membrane thickness before and after swelling. No negative influence was observed on the yeast growth when applying the cross-linker. The results of this study will hopefully add valuable information and helps in further studies using other cross-linkers to prepare robust capsules. / Program: Industrial Biotechnology

A tecnologia da microencapsulação apresenta várias aplicações na indústria de alimentos. Sabendo-se que diferentes fatores intrínsecos e extrínsecos dos alimentos podem influenciar a produção e atividade antimicrobiana das bacteriocinas produzidas pelas bactérias láticas, este estudo teve como principal objetivo avaliar a funcionalidade da encapsulação de bactérias láticas (BAL) bacteriocinogênicas em alginato de cálcio no controle de Listeria monocytogenes em salame experimentalmente contaminado. Para atingir este objetivo, foram isoladas novas cepas de BAL a partir de salame, que foram identificadas e caracterizadas quanto às propriedades das bacteriocinas produzidas, avaliando-se a influência do processo de encapsulação na produção de bacteriocinas. Foram isoladas quatro cepas produtoras de bacteriocinas, identificadas como Lactobacillus sakei (uma cepa), Lactobacillus curvatus (duas cepas) e Lactobacillus plantarum (uma cepa), nomeadas MBSa1, MBSa2, MBSa3 e MBSa4, respectivamente. As bacteriocinas produzidas pelas quatro cepas foram termoestáveis e com exceção da cepa MBSa2, sensíveis a pH acima de 8. Todas inibiram todas as cepas de Listeria monocytogenes testadas e várias espécies de BAL, mas foram inativas contra bactérias Gram negativas. As bacteriocinas foram purificadas por cromatografia de troca iônica seguida de cromatografia de interação hidrofóbica sequencial e cromatografia de fase reversa, observando-se que L. sakei MBSa1 produz um peptídeo de 4303 Da, com uma sequência parcial de aminoacidos idêntica à sequência presente em sakacina A. As cepas MBSa2 e MBSa3 produzem dois peptídeos ativos cada, idênticos nas duas cepas, um de 4457 Da e outro de 4360 Da, que apresentam sequências parciais idênticas às presentes na sakacina P e na sakacina X, respectivamente. Aparentemente, a cepa L. plantarum MBSa4 produz uma bacteriocina composta por duas sub-unidades. O DNA genômico da cepa L. sakei MBSa1 contém os genes da sakacina A e curvacina A, enquanto o DNA da cepa L. plantarum MBSa4 foi positivo para o gene da plantaricina W. A cepa L. curvatus MBSa2 foi encapsulada em alginato de cálcio e testada quanto à produção de bacteriocinas in vitro, observando-se que o processo de encapsulação não influenciou a produção de bacteriocina. Quando testada in situ, ou seja, no salame experimentalmente contaminado com Listeria monocytogenes, não foi observada ação anti-Listeria por L. curvatus MBSa2 encapsulado e não encapsulado, durante o 30 dias de fabricação do salame. / The microencapsulation technology has several applications in the food industry. Knowing that different intrinsic and extrinsic factors can influence production and antimicrobial activity of bacteriocins produced by lactic acid bacteria in foods, this study aimed at evaluating the functionality of the encapsulation of bacteriocinogenic lactic acid bacteria (LAB) in calcium alginate in the control of Listeria monocytogenes in experimentally contaminated salami. To achieve this goal, new strains of LAB were isolated from salami, identified and characterized for the properties of the produced bacteriocins, evaluating the influence of the encapsulation process in the bacteriocins production. Four bacteriocin producing strains were isolated and identified as Lactobacillus sakei (one strain), Lactobacillus curvatus (two strains) and Lactobacillus plantarum (one strain), named MBSa1, MBSa2, MBSa3 and MBSa4 respectively. The bacteriocins produced by the four strains were thermostable and with the exception of strain MBSa2, sensitive to pH above 8. All inhibited all tested Listeria monocytogenes strains and various species of LAB but were inactive against Gram-negative bacteria. The bacteriocins were purified by cation-exchange followed by sequential hydrophobic-interaction and reversed-phase chromatography, indicating that L. sakei MBSa1 produces a peptide of 4303 Da, with a partial amino acid sequence identical to the sequence present in sakacin A. L. curvatus MBSa2 and MBSa3 produce two active peptides, identical in the two strains, one of 4457 Da and the other of 4360 Da, with partial aminoacid sequences identical to those present in sakacin X and sakacin P, respectively. Apparently, L. plantarum MBSa4 produces a bacteriocin composed of two subunits. Genomic DNA of L. sakei MBSa1indicated that this strain contains genes for sakacin A and curvacin A, while the DNA of L. plantarum MBSa4 was positive for the plantaricin W gene. The strain L. curvatus MBSa2 was encapsulated in calcium alginate and tested for bacteriocin production in vitro, observing that the encapsulation process did not affect the production of bacteriocin. When tested in situ, i.e. in the salami experimentally contaminated with L. monocytogenes was not observed anti-Listeria<i/> action by L. curvatus MBSa2 encapsulated and non-encapsulated during the 30 day manufacture of salami.

O deslocamento dorsal à esquerda de cólon maior, com aprisionamento no espaço nefroesplênico, é uma afecção relativamente comum nos equinos, e quando ocorre a recidiva recomenda-se o fechamento desse espaço. Algumas técnicas são descritas na literatura e já aplicadas na rotina clinicocirúrgica. Com o intuito de desenvolver técnica minimamente invasiva e de rápida execução, objetivou-se avaliar a efetividade e as possíveis complicações trans e pós-operatórias de duas técnicas de oclusão do espaço nefroesplênico, através de grampeamento laparoscópico, com e sem a utilização de implante de pericárdio homólogo conservado em glicerina a 98%. Para tanto, foram utilizados 11 equinos hígidos, divididos em dois grupos, sendo seis animais submetidos à fixação do implante de pericárdio por grampos de polidioxanona, recobrindo o espaço nefroesplênico (Grupo 1 - G1) e em cinco animais foi realizada a fixação do baço ao ligamento nefroesplênico com o mesmo tipo de grampos (Grupo 2 - G2). Os procedimentos foram realizados em posição quadrupedal, sob sedação, criando-se três portais no flanco esquerdo. Não houve dificuldade para realização de ambas as técnicas, sendo em média necessários 49,83 minutos (&#177;10,19) para o G1 e 30,20 minutos ((&#177;5,89) para o G2, com diferença significativa para p&lt;0,05. Na avaliação pós-operatória, observou-se elevação da temperatura corpórea acompanhada de leucocitose por neutrofilia no 7º dia no G1, aumento do fibrinogênio plasmático no G1 nos dias 7 e 14 quando comparados com o momento pré-operatório e no dia 7 comparativamente ao G2. Houve aumento das células nucleadas totais no líquido peritoneal no G1 nos dias 1, 3, 7, 14 e 30 quando comparado ao momento pré-operatório e em comparação entre os grupos observou-se aumento no G1 nos dias 1 e 3. O hematócrito e a contagem das hemácias do líquido peritoneal elevaram-se significativamente nos animais do G2 nos dias 1 e 3 do período pós-operatório quando comparado ao G1 e em relação ao momento pré-operatório houve diferença no dia 1 no G1. Ambos os grupos apresentaram parâmetros físicos, valores de hemograma e de líquido peritoneal dentro dos valores de referência na avaliação realizada aos 60 dias do período pós-operatório. A laparoscopia exploratória realizada neste momento, para avaliação da efetividade das técnicas, mostrou a oclusão do espaço nefroesplênico no G1 em todos os animais, não sendo possível visualizar o implante de pericárdio, que se encontrava recoberto por tecido fibroso. Nesse grupo foram observadas sinéquias em dois animais, e em outros dois observou-se aderência de epíplon na região. No Grupo 2, apenas um animal apresentou oclusão parcial do espaço nefroesplênico, e nos outros quatro animais observou-se deiscência completa da fixação. Conclui-se que a técnica de ablação laparoscópica do espaço nefroesplênico, utilizando grampos de polidioxanona, foi efetiva apenas quando associada ao implante de pericárdio homólogo, apesar de causar alterações mais significativas no hemograma, na concentração de fibrinogênio plasmático e contagem de células nucleadas no líquido peritoneal, sugerindo maior reação inflamatória pela presença do implante biológico. / The left displacement of large colon, with nephrosplenic entrapment, is a common disease in horses and in cases of recurrence, the nephrosplenic space ablation aften is recommended. Techniques of nephrosplenic space ablation are reported in the literature and routinely used as a surgical treatment option in horses affected by this condition. In order to develop a simple minimally invasive technique, the aim of this study was to evaluate the efficacy and potential complications during surgery and postoperative period of two laparoscopic nephrosplenic space ablation techniques using staples, with or without the association of pericardium homologous implant preserved in 98% glycerin. Therefore, eleven sound horses, divided in two groups, were submitted to a laparoscopic procedure. Six horses were submitted to homologous pericardium implant covering nephrosplenic space (Group 1 G1) and five horses were submitted to a spleen fixation at the nephrosplenic ligament (Group 2 G2). Both techniques used polidioxanone staples. The surgical procedures were performed under sedation in standing position. Three portals were created on the left flank. There was no difficulty to realize the two techniques. It was necessary 49,83 minutes (&#177;10,19) to perform the technique in G1 and 30,20 minutes (&#177;5,89) in G2, with significant difference (p&lt;0,05). In the postoperative period it was observed corporeal temperature elevation and neutrophilic leukocytosis at day 7 in G1, increased plasmatic fibrinogen in G1 at days 7 and 14 compared to the preoperative period and at day 7 comparatively to G2. There was increased total nucleated cells in the peritoneal fluid in G1 at days 1, 3, 7, 14 and 30 compared to preoperative moment and in G1 at days 1 and 3 when compared between groups. The hematocrit and red blood cells count in the peritoneal fluid were significantly increased in G2 at days 1 and 3 when compared to G1, and in G1 at day 1 when compared to the preoperative moment. Both groups presented normal clinical parameters, hemogram and peritoneal fluid analysis at day 60 of the postoperative period. The exploratory laparoscopy performed at this time to evaluate the efficacy of the techniques showed a complete nephrosplenic ablation on the six horses in G1. In this group, it was not possible to differentiate the homologous pericardium implant and the fibrous scar tissue and sinequiae was observed in two horses, and epíplon adhesion in other two. In the Group 2, only one horse presented partial occlusion of the nephrosplenic space and complete dehiscence was observed on the other four. In conclusion, the laparoscopic nephrosplenic space ablation technique performed in this study, using polidioxanone staples, was effective only when associated to the homologous pericardium implant in spite of causing more significant alterations in the hemogram, plasma fibrinogen concentration and nucleated cell count in the peritoneal fluid, suggesting a greater inflammatory reaction due to the presence of the biological implant.

The security of wireless networks and systems is becoming increasingly important as wireless devices are more and more ubiquitous nowadays. The wireless channel exhibits the spatial uncorrelation property, which is that the characteristics of a wireless channel become uncorrelated every half carrier wavelength over distance. This property has prompted an emerging research area that utilizes wireless channel characteristics to achieve location distinction, to detect location changes or facilitate authentication of wireless users, and to establish shared secret key between legitimate communicators. This dissertation includes two work toward the security improvement of existing wireless networks and systems. With the discovered channel camouflage and manipulation techniques in wireless networks, traditional wireless channel based authentication or secure communication systems are broke or renovated. The first work proposes a new attack against all existing location distinction approaches that are built on this spatial uncorrelation property. With the discovered attack, an attacker can easily bypass authentication or camouflage location changes by creating an artificial wireless channel similar to a legitimate one. This dissertation also presents a detection technique that utilizes an auxiliary receiver or antenna to identify these fake channels. On the other hand, the second work shows that the legitimate users can also benefit from constructing these artificial wireless channels and apply them in a novel wireless key establishment. The proposed technique enables the transmitter to specify any content as the secret key and securely deliver it to the target receiver, and meanwhile removes the reconciliation process which is necessary for conventional wireless key establishment schemes.

Thesis (Ph. D.)--University of Chicago, Dept. of History, June 2002. / Includes bibliographical references. Also available on the Internet.

No description available.

This thesis contributes to the growing body of gender-specific health research by integrating both psychological and neuroendocrine data to assess the impacts of stress and violence on women's health. Women seeking support for intimate partner violence (IPV) were compared with women seeking support for non-interpersonal stressors (stress associated with immigration). Psychological measures included perceived stress and entrapment and mental defeat (EMD) scores as well as assessment of Axis I disorders. Neuroendocrine measures included basal levels of salivary cortisol and percent suppression of cortisol after the low-dose dexamethasone suppression test (DST). Positive relationships were found between experiences of IPV and perceived stress, EMD and Axis I diagnosis. The neuroendocrine measures did not differentiate IPV from non-interpersonal stressors and both groups showed hypersuppression of cortisol after the DST. IPV influences women's perceptions about EMD and perceived stress. By integrating neuroendocrine and psychological measures, further development of gender-specific stress models may occur.

Made available in DSpace on 2014-06-11T19:22:50Z (GMT). No. of bitstreams: 0 Previous issue date: 2003Bitstream added on 2014-06-13T20:09:57Z : No. of bitstreams: 1 almeida_mj_me_botfm.pdf: 1055929 bytes, checksum: 094af3d450a40ed69470b19fce7d47b7 (MD5) / A Síndrome do Aprisionamento da Artéria Poplítea (SAAP) é uma doença caracterizada pela compressão extrínseca dessa artéria, causada pelo desvio de seu trajeto anatômico habitual ou por estruturas músculo-tendinosas da fossa poplítea. Os sintomas clínicos costumam aparecer quando os indivíduos realizam esforços físicos. Distinguem-se dois tipos de SAAP: a clássica ou congênita e a funcional ou adquirida. Na forma clássica, distúrbios do desenvolvimento embrionário provocam anomalias da artéria poplítea ou de estruturas adjacentes que ocasionam a compressão. Na forma funcional ou adquirida, identifica-se apenas hipertrofia dos músculos gastrocnêmios como possível causa do encarceramento. O diagnóstico, em ambos os tipos, é feito pela detecção de oclusão ou estenose significativa da artéria poplítea às manobras de dorsiflexão e hiperextensão ativa dos pés, utilizando-se o mapeamento dúplex, a ressonância magnética ou a arteriografia. A identificação desses testes positivos em indivíduos assintomáticos e sem alterações anatômicas, trouxe questionamentos a respeito da especificidade dos testes diagnósticos. Neste trabalho é feita uma revisão da SAAP anatômica e funcional, além de serem discutidas a acurácia, sensibilidade e especificidade dos testes diagnósticos em cada caso. / The popliteal artery entrapment syndrome (PAES) is characterized by extrinsic compression of this artery as a result of anatomic deviation from its usual course, or by compression from musculotendinous structures in the popliteal fossa. Clinical symptoms onset when these affect individuals are undergoing stressing exercise. There are two types of PAES: classical or congenital form, and a functional acquired form. In the classical form, disturbances in the embryogenesis lead either directly to popliteal artery anomalies or to alterations of adjacent structures which cause compression of the popliteal artery. In the functional form, hypertrophy of the gastrocnemius muscle secondary to exercise has been postulated as a cause. In both types, diagnosis is made in subjects, on finding total occlusion or important stenosis of the popliteal artery. This is identified by duplex scan, magnetic resonance or arteriography during active plantar flexion-extension. A positive test in non-symptomatic subjects presenting no anatomical anomalies led to discussion regarding its sensibility and specificity. A review of anatomical and functional PAES besides a discussion about accuracy, sensibility and specificity of those diagnostics tests was made in this study.