O objetivo deste estudo foi comparar a eficácia anestésica de um volume de 1,8mL do cloridrato de articaína 4% com epinefrina 1:100.000 com um volume de 3,6mL do mesmo anestésico local no bloqueio convencional do nervo alveolar inferior (BNAI) e na injeção complementar no ligamento periodontal em pacientes com pulpite irreversível de molares mandibulares. Noventa pacientes do Setor de Urgência da Faculdade de Odontologia da Universidade de São Paulo receberam, aleatoriamente, 1 (1,8mL) ou 2 (3,6mL) tubetes da solução anestésica no BNAI. No caso de falha do BNAI, foram administrados os mesmos volumes pré-selecionados, aleatoriamente, na injeção complementar do ligamento periodontal. O sinal subjetivo de anestesia do lábio, a presença de anestesia pulpar e ausência de dor durante o procedimento de pulpectomia foram avaliados, respectivamente, por indagação ao paciente, por meio do aparelho estimulador pulpar elétrico e por uma escala analógica verbal. A análise estatística foi realizada por meio dos testes Qui-quadrado, Kruskal Wallis e Razão de Verossimilhancas. Após o BNAI, todos os pacientes reportaram anestesia no lábio. O volume de 1,8mL de articaína apresentou 27% de anestesia pulpar e o volume de 3,6mL apresentou 42%. A analgesia para o grupo de 1,8mL foi de 64% e para o volume de 3,6mL foi 73% após o BNAI, porém, essas diferenças não foram estatisticamente significantes. Na ocorrência da falha do BNAI, 64% dos pacientes sentiram dor na câmara pulpar, 32% em dentina e 4% no canal. Após a injeção no ligamento periodontal, o grupo de 1,8mL apresentou 75% de anestesia pulpar e o grupo de 3,6mL apresentou 42%. Em relação à analgesia durante o procedimento de pulpectomia, 31% dos pacientes do grupo de 1,8mL e 25% dos pacientes do grupo de 3,6mL apresentaram dor após a injeção no ligamento periodontal, porém, essas diferenças não foram estatisticamente significantes. Na ocorrência da falha da injeção do ligamento periodontal, 62% dos pacientes sentiram dor na câmara pulpar, 25% em dentina e 13% no canal. O aumento do volume de 1,8mL para 3,6mL da solução de articaína 4% com epinefrina 1:100.000 no BNAI e na injeção complementar no ligamento periodontal não aumentou significativamente a taxa de sucesso da anestesia pulpar e da analgesia. Portanto, os dois volumes anestésicos se comportam de forma semelhante, e não são efetivos no controle da dor durante o tratamento da pulpite irreversível de molares mandibulares.. / The aim of this study was to compare the anesthetic efficacy of a 1.8mL volume of 4% articaine hydrochloride with epinephrine 1:100,000 with a volume of 3.6mL of the same anesthetic in the inferior alveolar nerve block (BNAI) during pulpetcomy procedure in patients with irreversible pulpitis in mandibular molars. Ninety patients from the Emergency Department of the School of Dentistry of the University of São Paulo received randomly 1 (1.8mL) or 2 tubes (3.6mL) of the anesthetic solution in the BNAI. In the case of failure of the BNAI, the same pre-selected volumes were administered in the complementary injection of the periodontal ligament. The subjective signal of lip anesthesia, the presence of pulp anesthesia and absence of pain during pulpectomy were evaluated, respectively, by patient inquiry, through the electrical pulp stimulator and by an analogical verbal scale. Statistical analysis was performed using the Chi-square, Kruskal Wallis and Reason of Verossimilhancas tests. After the BNAI, all patients reported anesthesia on the lip. The volume of 1.8mL of articaine presented 27% of pulpal anesthesia and the volume of 3.6mL presented 42%. Analgesia for the 1.8mL group was 64% and for the volume of 3.6mL it was 73% after the BNAI, but these differences were not statistically significant. In the occurrence of BNAI failure, 64% of the patients felt pain in the pulp chamber, 32% in dentin and 4% in the root. After injection into the periodontal ligament, the 1.8mL group had 75% of pulpal anesthesia and the 3.6mL group had 42%. Regarding analgesia during the pulpectomy procedure, 31% of the patients in the 1.8mL group and 25% of the patients in the 3.6mL group had pain after injection into the periodontal ligament, but these differences were not statistically significant. In the occurrence of failure of the periodontal ligament injection, 62% of the patients felt pain in the pulp chamber, 25% in dentin and 13% in the root. Increasing the volume from 1.8mL to 3.6mL of the 4% articaine solution with 1: 100,000 epinephrine in the BNAI and in the complementary injection in the periodontal ligament did not significantly increase the success rate of pulpal anesthesia and analgesia. Therefore, both anesthetic volumes behave similarly, and are not effective in controlling pain in the treatment of irreversible mandibular molar pulpitis.

O objetivo deste estudo foi comparar a eficácia anestésica da articaína 4%, da lidocaína 2%, ambas associadas à epinefrina 1:100.000, e da bupivacaína 0.5%, associada à epinefrina 1:200.000, durante pulpectomia em pacientes com pulpite irreversível em molares inferiores. Cento e cinco voluntários do Setor de Urgência da Faculdade de Odontologia da Universidade de São Paulo receberam, aleatoriamente, 3,6mL de um dos anestésicos locais para o convencional bloqueio do nervo alveolar inferior (BNAI). No caso de falha do BNAI, foram administrados 3,6mL da mesma solução como injeção complementar no ligamento periodontal. O sinal subjetivo de anestesia do lábio, a presença de anestesia pulpar e ausência de dor durante a pulpectomia foram avaliados, respectivamente, por indagação ao paciente, por meio do aparelho estimulador pulpar elétrico (pulp tester) e por uma escala analógica verbal. A análise estatística foi realizada por meio dos testes Qui-quadrado, Kruskal Wallis e Razão de Verossimilhanças. Foi adotado nível de significância de 0,05 (P <= 0,05). Todos os pacientes reportaram anestesia no lábio após o BNAI. A lidocaína apresentou valores superiores (42,9%) para a anestesia pulpar após o BNAI e após a injeção no ligamento periodontal (61,5%). A bupivacaína apresentou valores superiores para a analgesia (80%) após o BNAI e a lidocaína (92,3%) após a injeção no ligamento periodontal. Após a falha do BNAI, a dor na câmara pulpar foi a mais frequente para articaína e lidocaína e na dentina para a bupivacaína e após a falha da injeção no ligamento periodontal, a dor foi similar para articaína nas diferentes regiões; câmara, canal e dentina; para a bupivacaína foi mais frequente na dentina e para a lidocaína no canal. No entanto, essas diferenças não foram estatisticamente significantes. Portanto as três soluções anestésicas locais se comportam de forma semelhante e não apresentam efetivo controle da dor no tratamento da pulpite irreversível em molares inferiores. / The aim of this study was to compare the anesthetic efficacy of 4% articaine and 2% lidocaine both associated with 1:100,000 epinephrine and 0.5% bupivacaine associated with 1:200,000 epinephrine in patients with irreversible pulpitis of the mandibular molars during a pulpectomy procedure. One hundred and five volunteers from the Emergency Center of the School of Dentistry at University of São Paulo randomly received 3.6 mL of local anesthetic as a conventional inferior alveolar nerve block (IANB). The subjective signal of lip numbness, pulpal anesthesia and the absence of pain during the pulpectomy procedure were, respectively, evaluated by questioning the patient, stimulation using an electric pulp tester and a verbal analogue scale. Statistical analysis was performed using the chi-square test, Kruskal Wallis and likelihood rations. The level for significance of differences was P <= .05. All patients reported the subjective signal of lip numbness after the application of either IANB. Lidocaine showed higher values for pulpal anesthesia after the IANB (42.9%) and after injection in the periodontal ligament (61.5%). Bupivacaine presented higher values for analgesia after the IANB (80,0%) and lidocaine after injection in the periodontal ligament (92,3%). After the failure of the IANB, the pain in the pulp chamber was the most frequent to articaine and lidocaine and bupivacaine for dentin and after the failure of the periodontal ligament injection, the pain was equal to articaine in different regions, chamber, canal and dentin; for bupivacaine was greater in dentin and lidocaine was higher in the channel. However, these differences were not statistically significant. So the three local anesthetic solutions behave similarly and not present any effective pain control in the treatment of irreversible pulpitis in mandibular molars.

O objetivo deste estudo foi comparar a eficácia anestésica da articaína 4%, da lidocaína 2% e da mepivacaína 2%, todas associadas à epinefrina 1:100.000, durante pulpectomia em pacientes com pulpite irreversível em molares mandibulares. Sessenta e seis voluntários do Setor de Urgência da Faculdade de Odontologia da Universidade de São Paulo receberam, aleatoriamente, 3,6ml de um dos anestésicos locais para o bloqueio convencional do nervo alveolar inferior (NAI). No caso de falha do bloqueio, foram administrados 3,6ml da mesma solução como injeção complementar no ligamento periodontal. O sinal subjetivo de anestesia do lábio, a presença de anestesia pulpar e ausência de dor durante a pulpectomia foram avaliados, respectivamente, por indagação ao paciente, por meio do aparelho estimulador pulpar elétrico (pulp tester) e por uma escala analógica verbal. A análise estatística foi realizada por meio dos testes Qui-quadrado, Kruskal Wallis e Razão de Verossimilhancas. Todos os pacientes reportaram anestesia no lábio após o bloqueio do NAI. A mepivacaína apresentou valores superiores (68,2%) para a anestesia pulpar após o bloqueio do NAI e a lidocaína (90%) após a injeção no ligamento periodontal. A mepivacaína apresentou valores superiores para a analgesia (72,7%) após o bloqueio no NAI e a lidocaína (90%) após a injeção no ligamento periodontal. Após a falha do bloqueio do NAI, a dor na câmara pulpar foi a mais frequente e após a falha da injeção no ligamento periodontal, a dor no canal. No entanto, essas diferenças não foram estatisticamente significantes. Portanto as três soluções anestésicas locais se comportam de forma semelhante e não apresentam efetivo controle da dor no tratamento da pulpite irreversível em molares mandibulares. / The aim of this study was to compare the anesthetic efficacy of 4% articaine, lidocaine 2% and 2% mepivacaine, all associated with epinephrine 1:100,000 during pulpectomy in patients with irreversible pulpitis in mandibular molars. Sixty-six volunteers Sector Emergency Faculty of Dentistry, Universidade de São Paulo randomly received 3.6 ml of a local anesthetic to block conventional inferior alveolar nerve. In case of failure of the lock, were administered 3.6 ml of the same solution as in the periodontal ligament injection complement. The signal subjective lip anesthesia, the presence of pulpal anesthesia and no pain during pulpectomy were evaluated respectively by questioning the patient, via the stimulating device electrical pulp (pulp tester) and a verbal analogue scale. Statistical analysis was performed using the chi-square test, Kruskal Wallis and likelihood ratio. All patients reported lip anesthesia after blockade of the inferior alveolar nerve. The mepivacaine showed higher values (68.2%) for pulpal anesthesia after blockade of the inferior alveolar nerve and lidocaine (90%) after injection in the periodontal ligament. The mepivacaine showed higher values for analgesia (72.7%) after blocking the inferior alveolar nerve and lidocaine (90%) after injection in the periodontal ligament. After the failure of the blockade of the inferior alveolar nerve, the pain in the pulp chamber was the most frequent and after the failure of the periodontal ligament injection, pain in the channel. However, these differences were not statistically significant. Therefore, the three local anesthetic solutions behave similarly and did not exhibit effective pain management in treating irreversible pulpitis in mandibular molars.

Este trabalho busca descrever sistemas irreversíveis (aqueles que não obedecem ao balanceamento detalhado) usando o formalismo mecânico-estatístico que tem como base a dinâmica estocástica. Nossos principais objetivos são: (i) a investigação do comportamento crítico e das possíveis classes de universalidade em sistemas irreversíveis; (ii) a modelagem da dinâmica de propagação de epidemias. Primeiramente investigamos o modelo suscetível-infectado-recuperado (SIR) estocástico e espacialmente estruturado. Nesse modelo, os indivíduos são divididos em três classes: suscetível (S), infectado devido ao contato com um vizinho infectado, e um individuo infectado pode recuperar-se espontaneamente. Este modelo exibe transição de fase em que a doença se espalha e uma fase em que não há espalhamento da doença. Tratando cada par suscetível-infectado como uma conexão através da qual pode haver propagação da epidemia, mostramos que é possível estabelecer uma conexão entre o modelo SIR e o modelo de percolação. Assim, pudemos utilizar métodos da teoria de percolação usual para determinar o limiar de espalhamento epidêmico. Por meio de aproximações de campo médio dinâmico, simulações computacionais de Monte Carlo estacionárias e simulações dependentes do tempo, determinamos o ponto critico e o comportamento critico desse modelo. Ademais, propomos dois modelos para descrever um processo epidêmico de transmissão vetorial. Consideramos duas populações interagentes uma formada por vetores e a outra por hospedeiros. Os vetores podem ser suscetíveis (S) ou infectados (I), enquanto os estados permitidos para os hospedeiros são os mesmos do modelo SIR. O processo de transmissão da doença ocorre devido ao contato local de um hospedeiro (vetor) suscetível com um vetor (hospedeiro) infectado. Determinamos o limiar de infecção, o tamanho da epidemia e mostramos que ambos os modelos exibem transições de fase de segunda ordem e que pertencem à classe de universalidade da percolação dinâmica isotrópica. / This study aims to describe irreversible systems (those that do not obey detailed balance) using a statistical mechanics formalism based on stochastic dynamics. Our main objectives are: (i) to investigate the critical behavior and the possible universality classes in irreversible systems; (ii) and modeling the dynamics of epidemic spreading. First we investigate the stochastic and spatially structured susceptible-infected-recovered model (SIR). In this model, individuals are divided into three classes: susceptible (S), infected (I) and recovered (R). A susceptible individual may become infected due to contact with an infected neighbor, and an infected individual may recover spontaneously. This model exhibits a phase transition between a phase in which the epidemic spreads and a phase where there is no spreading of the disease. Treating each susceptible-infected pair as a connection through which there may be epidemic spreading, we show that it is possible to establish a connection between the SIR model and the percolation model. Thus we are able to use methods of the theory of standard percolation for determining the epidemic spreading. By means of dynamic mean-field approximations and stationary and time-dependent computational Monte Carlo simulations, we determine the critical point and critical behavior of this model. In addition, we propose two models to describe the vector transmitted epidemic process. We consider two interacting populations, one formed by vectors and other by hosts. The vectors may be susceptible (S) or infected (I), where the states allowed for the hosts are the same as those in the SIR model. Transmission of the disease occurs due to contact between a local host (vector) and a susceptible vector (host) infected. We determine the threshold of infection, the size of the epidemic, and show that both models exhibit second order phase transitions that belong to the universality class of dynamic isotropic percolation.

Das Lektin aus <i>Pisum sativum</i>, der Gartenerbse, ist Teil der Familie der Leguminosenlektine. Diese Proteine haben untereinander eine hohe Sequenzhomologie, und die Struktur ihrer Monomere, ein all-ß-Motiv, ist hoch konserviert. Dagegen gibt es innerhalb der Familie eine große Vielfalt an unterschiedlichen Quartärstrukturen, die Gegenstand kristallographischer und theoretischer Arbeiten waren. Das Erbsenlektin ist ein dimeres Leguminosenlektin mit einer Besonderheit in seiner Struktur: Nach der Faltung in der Zelle wird aus einem Loop eine kurze Aminosäuresequenz herausgeschnitten, so dass sich in jeder Untereinheit zwei unabhängige Polypeptidketten befinden. Beide Ketten sind aber stark miteinander verschränkt und bilden eine gemeinsame strukturelle Domäne. Wie alle Lektine bindet Erbsenlektin komplexe Oligosaccharide, doch sind seine physiologische Rolle und der natürliche Ligand unbekannt. In dieser Arbeit wurden Versuche zur Entwicklung eines Funktionstests für Erbsenlektin durchgeführt und seine Faltung, Stabilität und Monomer-Dimer-Gleichgewicht charakterisiert. Um die spezifische Rolle der Prozessierung für Stabilität und Faltung zu untersuchen, wurde ein unprozessiertes Konstrukt in <i>E. coli</i> exprimiert und mit der prozessierten Form verglichen. <br /> <br /> Beide Proteine zeigen die gleiche kinetische Stabilität gegenüber chemischer Denaturierung. Sie denaturieren extrem langsam, weil nur die isolierten Untereinheiten entfalten können und das Monomer-Dimer-Gleichgewicht bei mittleren Konzentrationen an Denaturierungsmittel auf der Seite der Dimere liegt. Durch die extrem langsame Entfaltung zeigen beide Proteine eine apparente Hysterese im Gleichgewichtsübergang, und es ist nicht möglich, die thermodynamische Stabilität zu bestimmen. Die Stabilität und die Geschwindigkeit der Assoziation und Dissoziation in die prozessierten bzw. nichtprozessierten Untereinheiten sind für beide Proteine gleich. Darüber hinaus konnte gezeigt werden, dass auch unter nicht-denaturierenden Bedingungen die Untereinheiten zwischen den Dimeren ausgetauscht werden.<br /> <br /> Die Renaturierung der unprozessierten Variante ist unter stark nativen Bedingungen zu 100 % möglich. Das prozessierte Protein dagegen renaturiert nur zu etwa 50 %, und durch die Prozessierung ist die Faltung stark verlangsamt, der Faltungsprozess ist erst nach mehreren Tagen abgeschlossen. Im Laufe der Renaturierung wird ein Intermediat populiert, in dem die längere der beiden Polypeptidketten ein Homodimer mit nativähnlicher Untereinheitenkontaktfläche bildet. Der geschwindigkeitsbestimmende Schritt der Renaturierung ist die Assoziation der entfalteten kürzeren Kette mit diesem Dimer. / The lectin from <i>Pisum sativum</i> (garden pea) is a member of the family of legume lectins. These proteins share a high sequence homology, and the structure of their monomers, an all-ß-motif, is highly conserved. Their quaternary structures, however, show a great diversity which has been subject to cristallographic and theoretical studies. Pea lectin is a dimeric legume lectin with a special structural feature: After folding is completed in the cell, a short amino acid sequence is cut out of a loop, resulting in two independent polypeptide chains in each subunit. Both chains are closely intertwined and form one contiguous structural domain. Like all lectins, pea lectin binds to complex oligosaccharides, but its physiological role and its natural ligand are unknown. In this study, experiments to establish a functional assay for pea lectin have been conducted, and its folding, stability and monomer-dimer-equilibrium have been characterized. To investigate the specific role of the processing for stability and folding, an unprocessed construct was expressed in <i>E. coli</i> and compared to the processed form.<br /> <br /> Both proteins have the same kinetic stability against chemical denaturant. They denature extremely slowly, because only the isolated subunits can unfold, and the monomer-dimer-equilibrium favors the dimer at moderate concentrations of denaturant. Due to the slow unfolding, both proteins exhibit an apparent hysteresis in the denaturation transition. Therefore it has not been possible to determine their thermodynamic stability. For both proteins, the stability and the rates of association and dissociation into processed or unprocessed subunits, respectively, are equal. Furthermore it could be shown that even under non-denaturing conditions the subunits are exchanged between dimers.<br /> <br /> Renaturation of the unprocessed variants is possible under strongly native conditions with 100 % yield. The processed protein, however, can be renatured with yields of about 50 %, and its refolding is strongly decelerated. The folding process is finished only after several days. During renaturation, an intermediate is populated, in which the longer of the two polypeptide chains forms a homodimer with a native-like subunit interface. The rate limiting step of renaturation is the association of the unfolded short chain with this dimer.

Noise exposure is one of the most prevalent causes of irreversible occupational disease in Sweden and in many other countries. In hearing conservation programs, aimed at preventing noise-induced hearing loss, audiometry is an important instrument to highlight the risks and to assess the effectiveness of the program. A hazardous working environment and persons affected by it can be identified by monitoring the hearing thresholds of individual employees or groups of employees over time. However, in order to evaluate the prevalence of occupational noise-induced hearing loss, relevant reference data of unexposed subjects is needed. The first part of this dissertation concerns the changes in hearing thresholds over three decades in two occupational environments with high noise levels in the province of Östergötland, Sweden: the mechanical and the wood processing industries. The results show a positive trend, with improving median hearing thresholds from the 1970s into the 1990s. However, the hearing loss present also in the best period, during the 1990s, was probably greater than if the occupational noise exposure had not occurred. This study made clear the need for a valid reference data base, representing the statistical distribution of hearing threshold levels in a population not exposed to occupational noise but otherwise comparable to the group under study. In the second part of the dissertation, reference data for hearing threshold levels in women and men aged from 20 to 79 years are presented, based on measurements of 603 randomly selected individuals in Östergötland. A mathematical model is introduced, based on the hyperbolic tangent function, describing the hearing threshold levels as functions of age. The results show an age-related gender difference, with poorer hearing for men in age groups above 50 years. The prevalence of different degree of hearing loss and tinnitus is described for the same population in the third part of the dissertation. The overall prevalence of mild, moderate, severe or profound hearing loss was 20.9% collectively for women and 25.0% collectively for men. Tinnitus was reported by 8.9% of the women and 17.6% of the men. Approximately 2.4% of the subjects under study had been provided with hearing aids. However, about 7.7% were estimated to potentially benefit from hearing aids as estimated from their degree of hearing loss. Noise-induced hearing loss primarily causes damage to the outer hair cells of the inner ear. The fourth and last part of the dissertation evaluates the outer hair cell function, using otoacoustic emission measurements (OAE). Prevalence results from three different measuring techniques are presented: spontaneous otoacoustic emissions (SOAE), transient evoked otoacoustic emissions (TEOAE) and distortion product otoacoustic emissions (DPOAE). Gender and age effects on the recorded emission levels were also investigated. Women showed higher emission levels compared to men and for both women and men the emission levels decreased with increasing age. The results from the OAE recordings were shown to be somewhat affected by the state of the middle ear. The study included tympanometry, and the relation of the outcome ofthis test to the otoacoustic emissions is described, where high middle ear compliance resulted in low emission level. Reference data for the tympanometric measurements are also presented. The results of this project form an essential part of the important work against noiseinduced hearing loss, which needs continuous monitoring. The reference data presented here will provide a valid and reliable data base for the future assessment of hearing tests performed by occupational health centres in Sweden. This data base will in turn prove useful for comparison studies for Sweden as a responsible fellow EU member country setting high standards for work force safety. The statistical distribution of hearing threshold levels as a function of age for men and women in tabulated form is available on the Swedish Work Environment Authority (Arbetsmiljöverket) web site: http://www.av.se/publikationer/bocker/fysiskt/h293.shtm.

The ideal of artificial intelligence can firstly be set as the ability of a mechanical (or electronic) agent to be able to, as a human, observe, reason, learn, communicate and act in complex environments and secondly, to explain this type of behaviour in humans, animals or any other type of agent. The aim of this study is firstly to determine whether this ideal is feasible and secondly, to look at the physicalist premise thereof, viz., everything is physical according to Dooyeweerd’s view of the creation, fall and redemption motive. First we determine the essence of artificial intelligence through the Curch–Turing thesis. We then place the essence of artificial intelligence alongside the essence of life firstly to see whether the construction of an artificial intelligence agent is possible and whether the subject artificial intelligence has something to say regarding intelligent behaviour in humans, animals and similar agents. Lastly we look at the physicalist premise of artificial intelligence viz., everything is physical from the reformative creation, fall and redemption motive. The Church–Turing thesis forms the boundary of what is feasible in artificial intelligence and what is not feasible. Every component of the thesis is limited to the arithmetic law sphere of Being, i.e. the succession of discrete elements in a set of elements. Any effort to reduce the spatial aspect of the being to the arithmetic aspect of Being, like the enumeration of irrational numbers, ends in an antinomy. Any artificial intelligence agent is in its nature limited to the arithmetic law sphere of Being. The structural intertwinement, which such an artificial intelligence agent has with its underlying physical components is, in contrast with living organisms that of an irreversible grounded enkapsis. Life and mind has, in contrast to the arithmetic seclusion of an artificial intelligence agent, a fullness and totality. It has an ability to unlock Being in its fullness, which comes to the fore in a way that any living organism unlocks the plastic horizon of Being in the respective internal and phenomenological horizons. The unlocking of the spatial aspect plays a key role with its kernel of totality, simultaneity and continuousness. In both these horizons, the organism is in a living enkapsis with both its underlying physical substrate and the physical things in its external surroundings. The ideal of artificial intelligence is thus a phantasm. The only comment it can give on biology is that which has to do with the succession of discrete elements in a system. Hempel’s dilemma and the halting problem expose the physicalist point of departure of everything is physical as a religious premise, which is not empirically verifiable. Instead of getting a better view of Being the contours of meaning of life as well as all the supra physical aspects of Being fades away or is denied with concealment of Being. The only way in which we can get the broadest possible insight into Being is in the light of the Word of God. / Thesis (M.Phil.)--North-West University, Potchefstroom Campus, 2011.

The ideal of artificial intelligence can firstly be set as the ability of a mechanical (or electronic) agent to be able to, as a human, observe, reason, learn, communicate and act in complex environments and secondly, to explain this type of behaviour in humans, animals or any other type of agent. The aim of this study is firstly to determine whether this ideal is feasible and secondly, to look at the physicalist premise thereof, viz., everything is physical according to Dooyeweerd’s view of the creation, fall and redemption motive. First we determine the essence of artificial intelligence through the Curch–Turing thesis. We then place the essence of artificial intelligence alongside the essence of life firstly to see whether the construction of an artificial intelligence agent is possible and whether the subject artificial intelligence has something to say regarding intelligent behaviour in humans, animals and similar agents. Lastly we look at the physicalist premise of artificial intelligence viz., everything is physical from the reformative creation, fall and redemption motive. The Church–Turing thesis forms the boundary of what is feasible in artificial intelligence and what is not feasible. Every component of the thesis is limited to the arithmetic law sphere of Being, i.e. the succession of discrete elements in a set of elements. Any effort to reduce the spatial aspect of the being to the arithmetic aspect of Being, like the enumeration of irrational numbers, ends in an antinomy. Any artificial intelligence agent is in its nature limited to the arithmetic law sphere of Being. The structural intertwinement, which such an artificial intelligence agent has with its underlying physical components is, in contrast with living organisms that of an irreversible grounded enkapsis. Life and mind has, in contrast to the arithmetic seclusion of an artificial intelligence agent, a fullness and totality. It has an ability to unlock Being in its fullness, which comes to the fore in a way that any living organism unlocks the plastic horizon of Being in the respective internal and phenomenological horizons. The unlocking of the spatial aspect plays a key role with its kernel of totality, simultaneity and continuousness. In both these horizons, the organism is in a living enkapsis with both its underlying physical substrate and the physical things in its external surroundings. The ideal of artificial intelligence is thus a phantasm. The only comment it can give on biology is that which has to do with the succession of discrete elements in a system. Hempel’s dilemma and the halting problem expose the physicalist point of departure of everything is physical as a religious premise, which is not empirically verifiable. Instead of getting a better view of Being the contours of meaning of life as well as all the supra physical aspects of Being fades away or is denied with concealment of Being. The only way in which we can get the broadest possible insight into Being is in the light of the Word of God. / Thesis (M.Phil.)--North-West University, Potchefstroom Campus, 2011.

Thesis (Ph. D.)--Ohio State University, 2006. / Full text release at OhioLINK's ETD Center delayed at author's request

Le transport des bruts paraffiniques, et tout particulièrement leur remise en écoulement après un arrêt, dans de longues conduites sous-marines soumises à de basses températures, peut être difficile du fait de l'augmentation de leur viscosité. Le comportement rhéologique d´une huile paraffinique modèle, possédant des propriétés macroscopiques d'écoulement analogues à celles des bruts paraffiniques, est d'abord analysé en utilisant la vélocimétrie par imagerie par résonance magnétique associée à des mesures de contrainte de cisaillement au sein d'une géométrie Couette. Nous montrons que lors d'un écoulement forcé à température constante le matériau subit une déstructuration irréversible qui dépend de l'intensité du cisaillement. Ainsi la contrainte apparente critique permettant l'écoulement du matériau dépend de l'histoire thermique et d'écoulement subie par le matériau. Nous étudions ensuite le comportement rhéologique complet de deux bruts réels à partir de différents types de tests rhéométriques (fluages, redémarrage, régime permanent, changement brusque de vitesse) pour différentes histoires d'écoulement, notamment pendant la période de refroidissement. Le comportement détaillé du matériau en régime transitoire ainsi observé peut alors être modélisé. De plus les variations du seuil de contrainte en fonction de l'histoire thermique et de l'écoulement sont aussi décrites, ce qui nous donne le champ de contrainte seuil dans la conduite à l'état initial. Le modèle dans son ensemble est finalement implémenté dans un code de calcul pour simuler le redémarrage de l´écoulement d'un brut paraffinique dans une conduite réelle / Transporting waxy crude oils through long pipelines at low temperatures may be challenging, particularly its flow restart after a pipeline shut-in, due to its viscosity increase. The rheological behavior of a model waxy oil with macroscopic flow properties analogous to waxy crude oils is first analyzed using Magnetic Resonance Imaging velocimetry associated to stress measurements in a Couette geometry. While flowing at constant temperature, major irreversible structure break depending on shear intensity are observed. Thus, the critical apparent shear stress beyond which the material flows depends on the thermal and flow histories of the oil. Next, the rheological behavior of two waxy crude oils is studied using rheometrical tests (creep tests, flow restarts, abrupt changes of shear rate and steady flow) after different flow histories, notably during the cooling process. Then, those experimentally observed trends are modeled. Additionally, a comprehensive study of the yield stress in function of flow and temperature histories is presented. It provides an approach for describing the yield stress field inside the pipeline at the flow restart moment. Finally, the entire rheological model is implemented in the computational code for simulating waxy crude oils flow restart of a real scale pipeline