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Industry competition in the long-run, with particular reference to the petrochemical industryParaskevopoulos, Dimitris January 1988 (has links)
No description available.
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The Role of Ovarian Metabolism in 4-Vinylcyclohexene Metabolites and 7,12-Dimethylbenz[a]anthracene Induced Ovotoxicity in MiceRajapaksa, Kathila Seuwandhi January 2007 (has links)
Ovarian toxicants 4-vinylcychlohexene (VCH) and 7,12-dimethylbenz[a]anthracene (DMBA) requires bioactivation to induce follicle loss. VCH is bioactivated to monoepoxides (1,2-VCM and 7,8-VCM), and subsequently to an ovotoxic diepoxide (VCD) by hepatic CYP 2A and CYP 2B. DMBA is sequentially bioactivated to the ovotoxicant DMBA-3,4-diol-1,2-epoxide by hepatic CYP 1B1, microsomal epoxide hydrolase (mEH), and CYP 1A1/1B1 enzymes. Even though the liver is the primary organ metabolizing VCH and DMBA to reactive intermediates, several studies suggest that the ovary can also metabolize these two compounds. Studies were designed to investigate the role of ovarian metabolism in the resulting ovotoxicity of these two compounds using a novel mouse ovarian culture system. The hypothesis was that the ovary can participate in bioactivation and detoxification of VCH/VCM and DMBA and thereby influence the resulting ovotoxicity.Postnatal day 4 CYP 2E1 wild-type, null and B6C3F1 mouse ovaries were incubated with 1,2-VCM, VCD or DMBA for various lengths of time. 28 day old female CYP 2E1 wild-type and null mice were dosed (15d, i.p) with VCH, 1,2-VCM, VCD, or sesame oil (control). Following incubations and dosing, ovaries were prepared for histological evaluation of follicle numbers, mEH mRNA level, or mEH protein level. Medium from cultures were analyzed by LC/MS for VCD-GSH adducts.DMBA was found to be a potent ovotoxicant compared to VCH/VCM/VCD. In the ovarian culture system, VCM-induced toxicity required the CYP 2E1 enzyme. However, in vivo dosing studies indicated that in the presence of hepatic metabolism the ovary plays a minimal role in VCH/VCM-induced toxicity. Studies utilizing LC/MS showed that once bioactivated to VCD, this ovotoxic metabolite can be detoxified by glutathione conjugation in the ovary. Follicle loss induced by the ovotoxicant DMBA was found to involve mEH enzyme in culture.Collectively, these studies show that the ovary has the capacity to bioactivate and detoxify ovotoxicants. In the presence of hepatic metabolism ovarian effects might play only a minimal role in the resulting toxicity. The role of ovarian metabolism in the whole animal needs to be further investigated, especially for potent toxicants such as DMBA that can induce ovotoxicity at nanomolar concentrations.
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Thermo-mechanical coupled damage behavior of pre-damaged rock sculptures and monuments - laboratory experiments and numerical simulationsLi, Jun 22 September 2017 (has links) (PDF)
Cotttaer sandstone is a quite popular material used for sculptures and monuments for almost 1,000 years. Such sculptures and monuments will be damaged after several years. The reasons for that could be different: mechanical damage due to carving by sculptors, expansion stresses due to salt crystallization or temperature change. Damages also happen sometimes after inappropriate consolidation.
Cottaer sandstone before and after consolidation was investigated by lab testing and numerical simulations in this thesis. The aim is to develop a simulation strategy which can simulate the thermomechanical coupled damage behavior at grain size level. The main research works of this thesis are as follows:
*Uniaxial compression tests, Brazilian tension tests and size effect tests were carried out to investigate the mechanical parameters of original Cottaer sandstone.
*Ultrasonic wave velocity measurement and special biaxial flexural tests were carried out to determine how deep the consolidation material penetrates and how much strength of sandstones is increased by using two different injection materials.
*A Voronoi-based numerical simulation strategy was developed which considers grain size, grain shape and pore size. Mineral components, intra- and inter-granular contacts and intra- and inter-granular fracturing were considered as well.
*Uniaxial compression tests and Brazilian tension tests of unconsolidated sandstone were simulated. This simulation strategy can capture inter- and intra-granular fracturing.
*Prediction of thermo-mechanical coupled behavior of consolidated and unconsolidated sandstone samples was performed. The simulation results show that thermal properties of grains and filled pores have influence on temperature distribution and fracture development in the sandstone. Also, thermal induced displacements are strongly influenced by boundary condition.
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On the limits of cheap talk for public good provisionCosta, Francisco Junqueira Moreira da 18 September 2008 (has links)
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063202007_Dissertação_Francisco_Junqueira_Costa.pdf: 351812 bytes, checksum: 1cbedf11fe59a9c983ffc29b89970b47 (MD5) / This article studies a model where, as a consequence of private information, agents do not have incentive to invest in a desired joint project, or a public good, when they are unable to have prior discussion with their partners. As a result, the joint project is never undertaken and inefficiency is observed. Agastya, Menezes and Sengupta (2007) prove that with a prior stage of communication, with a binary message space, it is possible to have some efficiency gain since 'all ex-ante and interim efficient equilibria exhibit a simple structure'. We show that any finite message space does not provide efficiency gain on the simple structure discussed in that article. We use laboratory experiments to test these results. We find that people do contribute, even without communication, and that any kind of communication increases the probability of project implementation. We also observed that communication reduces the unproductive contribution, and that a large message space cannot provide efficiency gain relative to the binary one.
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Thermo-mechanical coupled damage behavior of pre-damaged rock sculptures and monuments - laboratory experiments and numerical simulations: Thermo-mechanical coupled damage behavior of pre-damaged rock sculptures and monuments - laboratory experiments and numerical simulationsLi, Jun 13 September 2017 (has links)
Cotttaer sandstone is a quite popular material used for sculptures and monuments for almost 1,000 years. Such sculptures and monuments will be damaged after several years. The reasons for that could be different: mechanical damage due to carving by sculptors, expansion stresses due to salt crystallization or temperature change. Damages also happen sometimes after inappropriate consolidation.
Cottaer sandstone before and after consolidation was investigated by lab testing and numerical simulations in this thesis. The aim is to develop a simulation strategy which can simulate the thermomechanical coupled damage behavior at grain size level. The main research works of this thesis are as follows:
*Uniaxial compression tests, Brazilian tension tests and size effect tests were carried out to investigate the mechanical parameters of original Cottaer sandstone.
*Ultrasonic wave velocity measurement and special biaxial flexural tests were carried out to determine how deep the consolidation material penetrates and how much strength of sandstones is increased by using two different injection materials.
*A Voronoi-based numerical simulation strategy was developed which considers grain size, grain shape and pore size. Mineral components, intra- and inter-granular contacts and intra- and inter-granular fracturing were considered as well.
*Uniaxial compression tests and Brazilian tension tests of unconsolidated sandstone were simulated. This simulation strategy can capture inter- and intra-granular fracturing.
*Prediction of thermo-mechanical coupled behavior of consolidated and unconsolidated sandstone samples was performed. The simulation results show that thermal properties of grains and filled pores have influence on temperature distribution and fracture development in the sandstone. Also, thermal induced displacements are strongly influenced by boundary condition.
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Propiedades psicométricas del Cuestionario de Violencia entre Novios universitarios / Psychometrics Properties of the Dating Violence QuestionnaireRaiser Velarde, Romina Esperanza 04 December 2020 (has links)
El objetivo del presente estudio fue determinar las propiedades psicométricas del Cuestionario de Violencia entre Novios (Rodríguez, López, Rodríguez, Bringas & Antuña, 2010) en universitarios de la provincia de Tacna, Perú. La muestra estuvo compuesta por 500 estudiantes de una universidad privada, con edades entre 18 a 30 años. Se aplicó el Cuestionario de Violencia entre Novios y la Escala de Violencia contra las mujeres en relaciones de pareja (Vara & López, 2016). Para evaluar la evidencia de validez de la estructura interna del instrumento, se realizó un análisis factorial confirmatorio, el cual dio como resultado como resultado adecuado índices de ajuste para el modelo de ocho factores relacionados (χ²/gl = 4.574, CFI = .961, TLI = .956 SRMR = .054, RMSEA = .085). Se calculó la consistencia interna y se obtuvieron valores alfa y omega que oscilan entre .84 y .91. Se utilizó la prueba no paramétrica de Spearman para el análisis de validez convergente. El análisis de correlaciones entre factores del modelo planteado y la escala de VcM dio como resultado que todas son positivas y estadísticamente significativas (p < .05), con magnitud alta (rs > .50) y moderada (rs > .30). Se concluye que el CUVINO cuenta con adecuadas propiedades psicométricas para su uso en la muestra de estudio. / The objective of this study was to determine the psychometric properties of the Dating Violence Questionnaire (Rodríguez, López, Rodríguez, Bringas & Antuña, 2010) in university students in the province of Tacna, Peru. The sample consisted of 500 students from a private university, aged between 18 and 30 years. The Questionnaire of Violence between Boyfriends and the Scale of Violence against women in relationships were applied (Vara & López, 2016). To assess the evidence of validity of the internal structure of the instrument, a confirmatory factor analysis was performed, which resulted in adequate fit indices for the model of eight related factors (χ² / gl = 4.574, CFI = .961, TLI = .956, SRMR = .054, RMSEA = .085). The internal consistency was calculated and alpha and omega values ranging between .84 and .91 were obtained. Spearman's nonparametric test was used for convergent validity analysis. The analysis of correlations between factors of the proposed model and the VcM Scale showed that all of them are positive and statistically significant (p <.05), with a high magnitude (rs > .50) and moderate (rs > .30). It is concluded that CUVINO has adequate psychometric properties for its use in the study sample. / Tesis
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Nanoscale resistive switching memory devices: a reviewSlesazeck, Stefan, Mikolajick, Thomas 10 November 2022 (has links)
In this review the different concepts of nanoscale resistive switching memory devices are described and classified according to their I–V behaviour and the underlying physical switching mechanisms. By means of the most important representative devices, the current state of electrical performance characteristics is illuminated in-depth. Moreover, the ability of resistive switching devices to be integrated into state-of-the-art CMOS circuits under the additional consideration with a suitable selector device for memory array operation is assessed. From this analysis, and by factoring in the maturity of the different concepts, a ranking methodology for application of the nanoscale resistive switching memory devices in the memory landscape is derived. Finally, the suitability of the different device concepts for beyond pure memory applications, such as brain inspired and neuromorphic computational or logic in memory applications that strive to overcome the vanNeumann bottleneck, is discussed.
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Designing Natural Haptic Interfaces and SignalsSang-Won Shim (6620390) 14 May 2019 (has links)
This thesis research is concerned with the exploration, design, and validation of novel haptic technologies and signals that feel natural and meaningful in a calm and pleasant way. Our ultimate goal is to expand the possibilities of human-machine interaction by developing a single tactile display and a set of signals through a systematic design approach. It is generally a challenge to evoke a broad range of emotions with vibrotactile stimulation, especially at low signal intensities. During the first part of this thesis research, three types of prototypes were developed and explored using novel haptic technologies. The first was a circular array braille display consisting of eight small six-pin braille modules. The forty-eight pins were arranged in a circular shape to deliver circular tactile information such as time and direction. The second was a braille stick consisting of sixteen six-pin braille modules arranged in a row. The entire display could be easily grasped in the hand so that tactile information can be easily accessible. The third was a 3-by-3 electroactive polymer actuator array driven at high voltages that gives a subtle “tapping” feel on the skin. However, each of the three prototypes suffered from a limited range of expression and was not pursued further.<br> After the initial prototyping efforts, a 2-by-2 vibrotactile display, the palmScape, was conceived and developed. Custom-designed stimulation patterns based on natural phenomena that feel calm and pleasant were designed and implemented with the palmScape. We use text labels to set the context for the vibrotactile icons that attempt to capture and expresses natural metaphors through variations in signal amplitude, frequency, duration, rhythm, modulation, spatial extent, as well as slow movements. Fourteen participants evaluated twenty vibrotactile icons by rating the perceived valence and arousal levels. The twenty stimuli included sixteen custom-designed vibrotactile icons from this thesis research and four reference patterns from two published studies. The results show that our custom-designed patterns were rated at higher valence levels than the corresponding reference signals at similar arousal ratings. Five of the sixteen vibrotactile icons from this research occupied the fourth quadrant of the valence-arousal space that corresponds to calm and pleasant signals. These findings support the validity of the palmScape display and our signal design approach for achieving a calm and pleasant experience and the possibility of reaching a broader range of expressiveness with vibrotactile signals.<br> Future studies will continue with the design of signals that can express a broader range of metaphors and emotions through the palmScape, and build an emotional evaluation database that can be combined with other modalities. Our work can be further expanded to support an immersive experience with naturalistic-feeling vibrotactile effects and broaden the expressiveness of human-computer interfaces in media consumption, gaming, and other communicative application domains.
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