Different types of shocks, or the treatment of one of the players in a specific network, may influence not only the future performance of themselves but also affect their network connections. It is crucial to explore the behaviour of the whole network in response to such an event. This paper focuses on the cases of endogenously formed shock. The logic used in the peer effect literature is adopted to develop the dynamic model and accounts for the endogeneity of the shock. The model allows us to predict the endogenous part of the shock and use the remaining unexpected component to estimate the effect of the shock on the changes in the performance of network connections. The identification conditions for effect are derived, and the consistent estimation procedure is proposed. / Series: Department of Economics Working Paper Series

Exam failures of the students in a specific network may influence not only the future performance of the student but also all students from their friendship networks, affecting the overall cohort's performance. Therefore, it is crucial to understand how the whole network responses to failure. The difficulty of such analysis is incorporated in the probability of the failures being highly endogenous. In this paper, I am applying the novel identification and estimation approach to deal with such endogeneity. I am exploring the dynamic data on the students' networks in HSE, Nizhniy Novgorod. The results suggest that, on average, the exam failure of the friend have a negative effect on future performance. / Series: Department of Economics Working Paper Series

<pre>The plethora of potential homemade explosive (HME) formulations combined with the fact they often exhibit large critical diameters make them expensive to characterize with traditional large-scale tests. A relatively new method for small-scale characterization was investigated using non-ideal explosive charges consisting of ammonium nitrate (AN) and various fuels. This optical characterization technique utilizes the rate of reaction wave velocity decay in the failing detonations of sub-critical diameter charges as a metric for the shock sensitivity of an explosive. The conditions for detonation initiation and failure have long been used to investigate shock sensitivity (critical diameter, gap tests, run-to-detonation experiments); however, the failure regime still remains largely unexplored. The utility of this small-scale characterization technique lies in its ability to determine the relative shock sensitivity of explosive with minimal material and tests while simultaneously providing transient velocity data for potential use in modeling efforts. In this work, high speed imaging was used and analyzed to determine rates of reaction wave velocity decay in the AN-fuel samples. Among the fuels tested with AN were diesel (ANFO), nitromethane (ANNM), and aluminum (ANAl). It was found that nitromethane was the most effective at sensitizing the AN of the systems considered. In both ANNM and ANAl, maximum shock sensitivity occurred at fuel percentages below stoichiometric mixtures. This was speculated to be due to the competing effects of stoichiometry and hot spot criticality. Sensitivity results were compared to run-to-failure distances and published critical diameter trends and showed good agreement. </pre>

La généralisation du procédé d’assemblage par collage au sein des structures aérospatiales, aéronautiques et automobiles est confrontée au besoin d’évaluation non destructive quantitative des assemblages. Le procédé de test d’adhérence par choc laser (LASAT) répond à cette problématique par la sollicitation calibrée des joints collés et l’utilisation de diagnostics non-destructifs pour déterminer l’état résiduel des joints suite à cette sollicitation qui doit décoller les joints faibles et préserver l’intégrité structurelle des assemblages corrects. La détermination des paramètres laser optimaux pour mettre en œuvre ce test d’épreuve non-destructif (ND-LASAT) est réalisée par l’application d’une méthodologie bien définie. Cette dernière implique la caractérisation par une approche expérimentale et numérique de l’assemblage considéré, suivie d’une phase d’optimisation. La diversification des configurations d’interaction-laser matière impliquées dans ces configurations optimisées nécessite de disposer d’outils numériques pour prédire les chargements appliqués aux joints collés. Dans cette étude, le développement et la validation de modèles intégrés dans un code multi-physique répond à ce besoin. Un effort particulier a été porté sur l’évaluation de la précision des chargements simulés. Enfin, la démonstration du procédé ND-LASAT sur trois différents assemblages collés a été réalisée, validant ainsi la méthodologie et la chaine numérique développées dans cette étude. / Bonding process generalization within aerospace, aeronautical and automotive structures faces the need of quantitative non-destructive evaluation of assemblies. Laser shock adhesion test (LASAT) meets this requirement by applying a calibrated stress to bonded joints and using non-destructive diagnostics to determine the post-shock state of the joint. The calibrated stress must disbond weak joints and keep correct assemblies intact. Optimal laser parameters determination aims at implementing this non-destructive proof test (ND-LASAT). It is achieved through application of a well-defined methodology, which implies the concerned assembly characterization by an experimental and numerical approach, followed by an optimization step. Optimization implies diversification of laser-matter configurations. Use of numerical tools for predicting loadings applied to bonded joints is then required. Models development within a multi-physics code is proposed and validated here to respond to this need. A significant effort has been made for evaluating models’ precision. Experimental demonstration of ND-LASAT process is achieved on three different bonded assemblies, and thus validating both methodology and numerical chain developed in this study.

Student Number : 9803381J - MSc Dissertation - Faculty of Engineering and the Built Environment / Although pulsed power has been used in many parts of the world over the last few decades to initiate high-voltage discharges through rock, no systematic test work on South African ore bodies and related rock types has been done so far. As part of CSIR Miningtek’s integrated approach of combining underground comminution with a novel Tore© hydrotransport system, which has been shown to operate well with coarse particles up to 10 mm, various rock types were fragmented in single discharge mode under laboratory conditions. The work was conducted at the University of the Witwatersrand’s high-voltage laboratory with a custom-designed test rig. The rig configuration was based on a critical review and analysis of the literature and on assessments of existing test facilities elsewhere. Core samples with diameters ranging from 16 to 48 mm were cut from test specimens with thicknesses ranging from 8 to 48 mm. Rock types included Ventersdorp Contact Reef, Carbon Leader, Elsburg Formation, UG2 and Merensky, as well as pure quartz, shales, lava and dykes. A six-stage Marx generator provided a voltage rise time of 2 000 kV/μs to create a discharge through the rock, in preference to a discharge through the surrounding water, which acts as an insulator at ramp-up times faster than 0,5 μs. High-speed photography, and an analysis of the voltage and current signals for various rock types and for water alone, were used to quantify the potential benefits of rock breaking by electric discharge. It was found that some Kimberlite specimens and mineralised gold-bearing reefs were much easier to fragment than hanging wall or footwall material. Merensky reef appeared to be more susceptible than the less brittle UG2 material. A correlation was derived between the dynamic resistivity of various rock types, measured at 16 MHz excitation frequency, and the electrical breakdown strength at which discharge took place. The fragments created had a more cubical shape than would be created by conventional impact crushing. However, the high voltage requirements of about 30 to 35 kV per millimetre of rock thickness would necessitate not only efficient mechanical and electrical contact between the electrodes and the rock, but also considerable safety features for underground installations. The clearly identified, preferential fracturing of reef rock types, compared with the hanging or footwall materials, suggests that the greater benefit of electric rock breaking may lie in primary rock breaking as a mining method, rather than in secondary comminution of broken rock to enable hydraulic transportation by pipeline to surface.

Trata-se de compreender como se articula um sistema de filosofia que, emerso da Crítica kantiana, não pode nem fazer apelo aos objetos da metafísica especial, nem pressupor qualquer positividade, como a lógica e a coisa em si, constituindo-se, pois, como uma doutrina-da-ciência. Ao nosso ver, essa articulação tem seu núcleo central em um primado da prática: a Fundação da Ciência do Prático, terceira parte da Fundação de toda a Doutrina-da-Ciência, tem seu lugar no sistema ao solucionar as contradições e limites que o saber teórico deixou e que, como mera teoria, é incapaz de dar conta , mostrando que é apenas a partir do primado da faculdade prática, fundada na exigência do eu absoluto de realizar a infinitude e na lei do eu de refletir sobre si mesmo como realizando tal idéia, que se funda o sistema do saber humano e, portanto, a representação. Parece-nos que este momento da exposição da doutrina-daciência de 1794 permite a descrição do idealismo transcendental de Fichte como um idealismo crítico, herdeiro da filosofia kantiana. / Our aim is to understand how Fichte´s system of philophy is articulated, provided that it, coming from Kant´s Critic, cannot make appeal either to the objects of special metaphysics or pressuposes any positivity like logics or the thing in itself and therefore arrives at a Doctrine of Science (Wissenschaftslehre). In our interpretation, this articulation is centered on the primacy of practice: the \"Foundation of the Science of Practice\", third part of the Foundation of the Entire Doctrine of Science, fits in the system as it solves the contradictions and limits of the theoretical knowledge by showing that only the primacy of the practical faculty, grounded in the necessity of the realization of infinity by the absolute I and in the law of self-reflection as the realization of this idea, can found the system of human knowledge and hence the representation. It seems that this moment of the exposition of 1794´s Doctrine of Science allows the description of Fichte´s transcendental idealism as a critic idealism, heir of kantian philosophy.

Sabe-se que o feto é vulnerável a modificações do millieu materno, especificamente, a exposição a um estressor ativa sistemas neuroendócrinos (expoentes o eixo hipotálamo-hipófise-adrenais HPA e o sistema nervoso autônomo simpático SNAS). Quando no terço final da gestação, essas mudanças podem interferir com o desenvolvimento/ maturação neuroimune. Estudos prévios de nosso grupo demonstraram que, o estresse pré-natal diminuiu significativamente a imunidade inata e aumentou o turnover de noradrenalina hipotalâmica de camundongos, dados que somados a outros de literatura levaram aos objetivos deste trabalho: analisar os efeitos de um estresse pré-natal sobre parâmetros de linfócitos de camundongos. Os resultados obtidos mostraram que a aplicação de choques nas patas (0,2 mA, 10 choques/sessão), tanto no terço final gestacional quanto após desafio agudo pós-natal, contudo, não modificou significativamente os parâmetros linfocitários avaliados. Baseado nisto, levantamos hipóteses: 1- a existência de vias de redundância fisiológica capacitaria o organismo a manter sua homeostasia frente aos estressores empregados; 2- inaptidão do modelo de estresse empregado; 3- ausência de desafio imune prévio à análise de um sistema que é responsivo (adaptativo). A primeira hipótese confirmou-se quando desenvolvemos como estresse pós-natal o modelo do estresse do metrô de Nova Iorque; a segunda hipótese confirmou-se também verdadeira através de desafio em modelo experimental de a asma OVA-induzida; finalmente, a terceira hipótese foi confirmada por estudos de outros autores. / As a consequence of his fast development, the fetus is vulnerable to modifications from the hormonal maternal millieu. This is explained mainly by the permeability of the placentary barrier to several hormones and substances. Specifically, it is known that the maternal exposition to a stressor activates neuroendocrine systems (exponents, the hypothalamus-pituitary-adrenal axis HPA, and the sympathetic autonomic nervous system SANS), causing an exaggerated production of neuropeptides, which have the potential to change the motherly-fetus homeostasis. When this unbalance occurs in the final three months of pregnancy, it may impact fetal systems that are still being developed/matured, as the immune and nervous systems. According to previous studies, the prenatal-stress proposed in this work was able to produce a significant decrease on innate immunity as assessed by the evaluation of the activity of peritoneal macrophages; it was also, a significant increment in hypothalamic noradrenaline turnover. Such prenatal events, could be derived and/or reflect a lost in adaptative immunity homeostasis. The objective of this work was, thus, to analyze lymphocyte parameters of prenatal stressed mice. A footshock stress (0,2 mA, 10 shocks of 5 seconds each/session) was applied both in the final third of gestation and/or in the postnatal adult life. Those stressors was anable to affect the lymphocytes viability and their subpopulation patterns token from peripheral blood; the esplenic lymphocytes proliferation ratio were also not changed. Those results suggested that: 1- the stress model was not effective; 2- the obtained results reflected the absence of an immune challenge applied previous by the experiments performedb; 3- the existence of physiologic redundancies turns the organisms able to react in a homeostatic way even exposed to stress situations.

Caulobacter crescentus é uma bactéria Gram-negativa de vida livre cujo ciclo celular depende de eventos de diferenciação celular. A célula pré-divisional assimétrica dá origem a duas células filhas morfológica e funcionalmente distintas: a célula-talo e a célula móvel. A expressão do operon groESL é regulada por choque térmico e durante o ciclo celular a temperaturas normais, sendo a transcrição máxima na célula pré-divisional, com níveis baixos na célula-talo. Numa linhagem superexpressando &#963;32, os níveis do mRNA e da proteína GroEL estão aumentados, indicando que a transcrição ocorre a partir de um promotor ativado por &#963;32. A região regulatória também apresenta uma sequência repetida invertida, CIRCE, em que mutações de ponto aumentam a transcrição apenas a temperaturas normais de crescimento, indicando o papel inibitório desse elemento. Fusões de transcrição groESL-/acZ com mutações em CIRCE deixam de apresentar regulação temporal, bem como a síntese de GroEL numa linhagem hrcA-, em que o gene codificando o provável repressor que se liga em CIRCE está interrompido. Estes resultados indicam que o sistem CIRCE/HrcA está envolvido com a regulação da expressão de groESL durante o ciclo celular. Tentativas de se construir uma linhagem com groEL interrompido não tiveram sucesso, indicando ser este um gene essencial em todas as temperaturas. Um mutante condicional de groESL foi construído por recombinação homóloga e, em condições restritivas, o crescimento é inibido, os níveis de DnaK aumentam e as células se tomam filamentosas, porém não foi observada lise celular. As proteínas essenciais que são dependentes de GroEL/GroES para atingirem sua conformação funcional ainda não foram determinadas. / Caulobacter crescentus is an aquatic free-living Gram-negative bacterium whose cell cycle depends on cell differentiation. The asymmetrical predivisional cell gives rise to two morphologically and functionally different daughter cells: the swarmer cell an the stalked cell. The expression of the groESL operon is induced by heat shock and is cell cycle controlled at normal temperatures, with maximal transcription in the predivisional cell and very low levels in the stalked cell. In this work, it was demonstrated that, in a strain overexpressing &#963;32, the levels of groESL transcripts and the synthesis of GroEL are increased, confirming that this factor is responsible for the transcriptional activation of the &#963;32 -like promoter of this operon, that also presents a inverted repeat called CIRCE in its regulatory region. groESL-lacZ transcription fusions with point mutations in CIRCE indicated a negative role of this cis-acting element only at normal growth temperatures, with a minor effect on heat shock induction. In addition, the expression of these fusions are no longer cell-cycle regulated, as well as GroEL synthesis in a strain which does not have the HrcA protein, the putative repressor that binds CIRCE, indicating that the CIRCE-HrcA system are involved in cell cycle regulation of groESL in C. crescentus. It was also shown that groEL is an essential gene at normal growth temperatures, since a strain with groEL disrupted is not viable. A conditional mutant was obtained by homologous recombination and in restrictive conditions growth is inhibited, DnaK levels are increased and the cells become filamentous, but no celllysis was observed. The proteins that require GroEL/GroES for proper folding have not been identified yet.

A dexmedetomidina, fármaco da classe dos &alpha;2-agonistas, é amplamente empregada no paciente gravemente enfermo por seus efeitos de analgesia e sedação, porém seu comportamento nas situações de sepse e choque séptico é pouco estudado. O objetivo deste estudo foi avaliar os efeitos hemodinâmicos, metabólicos e inflamatórios da dexmedetomidina em modelo suíno de choque séptico. Foram utilizadas 18 fêmeas suínas (peso médio 23,5 kg), divididos em três grupos. O grupo SHAM foi submetido apenas à anestesia. O grupo CH recebeu infusão intravenosa de E. coli O55 (3x109 ufc/mL) de 0,75 ml/kg durante 1 hora. Os animais do grupo CHDEX receberam a mesma infusão de bactérias vivas, associada à infusão de dexmedetomidina 0,7 &mu;g/kg em 10 minutos seguida de 0,5 &mu;g/kg/h até o fim do experimento. Foi considerado T0 o momento do fim da infusão da bactéria, e os animais foram observados por 240 minutos. Os animais receberam tratamento com fluidoterapia e/ou norepinefrina para manutenção da PVC 8 mmHg e PAM 65 mmHg. O modelo proposto mimetizou as alterações presentes na sepse grave e choque séptico, com colapso circulatório, lesão pulmonar aguda e acidose metabólica. Houve tendência de maior depressão cardiovascular em CHDEX (índice cardíaco em T240: 2,8±0,5 L.min-1.m-2 para CHDEX; 3,6±1,7 L.min-1.m-2 para CH e 4,7±1,1 L.min-1.m-2 para SHAM). Não houve diferença estatística entre os grupos CH e CHDEX, à exceção da SvO2 (62,5±9,0% para CHDEX, 74,2±9,1% para CH em T180), do consumo de oxigênio (149,90±25,62 mL.min-1.m-2 para CHDEX, 111,49±21,59 mL.min-1.m-2 para CH em T0), da taxa de extração de oxigênio (43±20% para CHDEX, 25±11% para CH em T240) e do Pr-Pa (53±14mmHg para CHDEX, 35±11mmHg para CH em T0). A diminuição no IC justifica a diminuição dos parâmetros de oxigenação. Os níveis plasmáticos de TNF-&alpha;, IL-1&beta;, IL-6 e IL-10 aumentaram de forma mais pronunciada em CH, mas não houve diferença estatisticamente significativa com relação a CHDEX. Ambos os grupos não diferiram em relação ao débito urinário e tratamento de ressuscitação empregado. Frente aos resultados obtidos pode-se pressupor que a dexmedetomidina pode desencadear desequilíbrio entre oferta e consumo de oxigênio por afetar diretamente a microcirculação. Sugere-se que o emprego da dexmedetomidina no choque séptico seja alvo de mais estudos e discussões. / The use of dexmedetomidine to achieve sedation, anxiolysis, analgesia and allowance to mechanical ventilation has increased in critical ill patients, but only a few data are available regarding the effects of dexmedetomidine in situations of sepsis and septic shock. The aim of this study was to assess hemodynamic, metabolic and inflammatory effects of dexmedetomidine in a porcine model of septic shock. Eighteen sows with mean weight of 23,5 kg were included in the study, and allocated in three groups. Animals in the SHAM group underwent a standard anesthetic protocol. The CH group, in addition to anesthesia, received an intravenous infusion of live E. coli O55 (3x109 cfu/mL), total volume of 0,75 ml/kg in 1 hour. The CHDEX group underwent the same treatment of the CH group plus 0,7 &mu;g/kg of dexmedetomidine over 10 minutes and a constant rate of infusion of 0,5 &mu;g/kg/h until the end of the experiment. T0 was considered the end of bacteria infusion and animals were monitored during 240 minutes. Fluid therapy and/or norepinephrine infusion were given as needed, aiming to maintain central venous pressure 8 mmHg and mean arterial pressure 65 mmHg. Typical septic shock symptoms were shown in animals receiving bacteria infusion, such as cardiovascular collapse, acute lung injury and metabolic acidosis. It was observed a greater cardiovascular depression in the CHDEX group (T240 cardiac index: 2,8±0,5 L.min-1.m-2 within CHDEX; 3,6±1,7 L.min-1.m-2 within CH e 4,7±1,1 L.min-1.m-2 within SHAM). There was not statistical difference between CH and CHDEX, but concerning SvO2 (62,5±9,0% within CHDEX, 74,2±9,1% within CH: moment T180) oxygen consumption (149,90±25,62 mL.min-1.m-2 within CHDEX, 111,49±21,59 mL.min-1.m-2 within CH: moment T0), oxygen extraction rate (43±20% within CHDEX, 25±11% within CH: moment T240) and Pr-Pa (53±14mmHg within CHDEX, 35±11mmHg within CH: moment T0). Impaired cardiac index justified changes in oxygenation parameters. TNF-&alpha;, IL-1&beta;, IL-6 and IL-10 plasma levels were increased in a more pronounced way in the CH group, although no statistical differences were found when compared with the CHDEX group. Both groups presented similar results concerning urine output, fluid therapy and norepinephrine additional treatments. Dexmedetomidine is likely to cause a mismatch between oxygen delivery and consumption by affecting microcirculation in critical ill patients. Further investigations on the use of dexmedetomidina in septic shock are required.

O trauma constitui importante problema de saúde pública, com grande impacto sócio-econômico e muitas mortes. Visto que poucos pesquisadores traçam perfil epidemiológico e fatores preditores de óbito de forma integrada e prospectiva, este estudo foi idealizado com o objetivo de identificar preditores independentes de mortalidade em trauma e seu mapeamento populacional, visando melhorar o atendimento a politraumatizados graves. Após aprovação da comissão de ética em pesquisa institucional, estudo longitudinal, prospectivo e observacional foi conduzido entre 2010 e 2013 na região metropolitana da Grande São Paulo/Brasil com vítimas de politrauma grave (Injury Severity Score >15). A coleta de dados clínico-laboratoriais foi realizada em 4 momentos: 1- pré-hospitalar, 2- sala de emergência, 3- após 3 horas da admissão e 4- após 24 hs da admissão. O desfecho principal foi mortalidade em 30 dias. Os dados foram analisados com teste t de Student ou Mann-Whitney, ANOVA não paramétrica, e Equações de Estimação Generalizadas (EEG) para medidas repetidas (p < 0,05). A população total do estudo foi de 334 pacientes, sendo excluídos 124 por não adequação ao protocolo e incluídos 200 indivíduos na análise final. Os preditores independentes de mortalidade encontrados foram: saturação arterial de oxigênio de hemoglobina (OR=0,989; IC 95% 0,982-0,995- p < 0,001), pressão arterial diastólica (OR=0,998; IC 95% 0,995-0,998- p < 0,001), nível sérico de lactato (OR=1,046; IC 95% 1,012-1,082- p < 0,004), pontuação na escala de coma de Glasgow (OR=0,973;IC 95% 0,965-0,982-p < 0,001), quantidade de cristalóides infundidos (OR=1,013; IC 95% 1,000-1,025- p < 0,023 - a cada 1000 ml). Através das análises realizadas neste estudo foi possível concluir que os preditores independentes de mortalidade foram: hipoxemia, hipotensão arterial diastólica, hiperlactatemia, baixa pontuação na escala de coma de Glasgow e aumento de volume de cristalóides infundidos / Trauma is an important public health problem, with high socioeconomic impact and major adverse clinical outcomes. The epidemiological profile and predictors of death in trauma patients have not been addressed in an integrated and prospective way. Therefore, the present study was designed to identify independent predictors of mortality in trauma patients and their populational mapping to improve the care of severe polytrauma patients. After approval by the ethics in institutional research committee, the present longitudinal, prospective and observational study was conducted between 2010 and 2013 in the metropolitan area of São Paulo/Brazil with victims of severe polytrauma (Injury Severity Score >15). The collection of clinical and laboratory data was performed at 4 different time points: 1, pre-hospital; 2, in the emergency room; 3, at 3 hours after admission; and 4, at 24 hours after admission. The primary outcome was mortality within 30 days. The data were analyzed with Student\'s t-test or the Mann-Whitney test, nonparametric ANOVA and Generalized Estimating Equations (GEE) for repeated measures (p < 0.05). The total study population consisted of 334 patients. In total, 124 patients were excluded for not fitting the protocol, and 200 individuals were included in the final analysis. The independent predictors of mortality were as follows: arterial hemoglobin oxygen saturation (OR=0.989, 95% CI 0.982-0.995, p < 0.001); diastolic blood pressure (OR=0.998, 95% CI 0.995-0.998, p < 0.001); serum lactate level (OR=1.046, 95% CI 1.012- 1.082, p < 0.004); score on the Glasgow coma scale (OR=0.973, 95% CI 0.965-0.982, p < 0.001); and the amount of infused crystalloid (OR=1.013, 95% CI 1.000-1.025, p < 0.023 - each 1000 ml). Through the analyses performed in this study, it was concluded that the independent predictors of mortality at any given time were as follows: hypoxemia; diastolic arterial hypotension; hyperlactatemia; a low score on the Glasgow coma scale; and volume of infused crystalloid