931 resultados para Epstein and Zin’s recursive utility function


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In this paper we explore the various spaces and sites through which the figure of the parent is summoned and activated to inhabit and perform market norms and practices in the field of education in England. Since the late 1970s successive governments have called on parents to enact certain duties and obligations in relation to the state. These duties include adopting and internalizing responsibility for all kinds of risks, liabilities and inequities formerly managed by the Keynesian welfare state. Rather than characterize this situation in terms of the ‘hollowing of the state’, we argue that the role of the state includes enabling the functioning of the parent as a neoliberal subject so that they may successfully harness the power of the market to their own advantage and (hopefully) minimize the kinds of risk and inequity generated through a market-based, deregulated education system. In this paper we examine how parents in England are differently, yet similarly, compelled to embody certain market norms and practices as they navigate the field of education. Adopting genealogical enquiry and policy discourse analysis as our methodology, we explore how parents across three policy sites or spaces are constructed as objects and purveyors of utility and ancillaries to marketisation. This includes a focus on how parents are summoned as 1) consumers or choosers of education services; 2) governors and overseers of schools; and 3) producers and founders of schools.

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Nuclear erythroid related factor-2 (NRF2) is known to promote cancer therapeutic detoxification and crosstalk with growth promoting pathways. HER2 receptor tyrosine kinase is frequently overexpressed in cancers leading to uncontrolled receptor activation and signaling. A combination of HER2 targeting monoclonal antibodies shows greater anticancer efficacy than the single targeting antibodies, however, its mechanism of action is largely unclear. Here we report novel actions of anti-HER2 drugs, Trastuzumab and Pertuzumab, involving NRF2. HER2 targeting by antibodies inhibited growth in association with persistent generation of reactive oxygen species (ROS), glutathione (GSH) depletion, reduction in NRF2 levels and inhibition of NRF2 function in ovarian cancer cell lines. The combination of antibodies produced more potent effects than single alone; downregulated NRF2 substrates by repressing the Antioxidant Response (AR) pathway with concomitant transcriptional inhibition of NRF2. We showed the antibody combination produced increased methylation at the NRF2 promoter consistent with repression of NRF2 antioxidant function, as HDAC and methylation inhibitors reversed such produced transcriptional effects. These findings demonstrate a novel mechanism and role for NRF2 in mediating the response of cancer cells to the combination of Trastuzumab and Pertuzumab and reinforce the importance of NRF2 in drug resistance and as a key anticancer target.

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In this paper we show how to construct the Evans function for traveling wave solutions of integral neural field equations when the firing rate function is a Heaviside. This allows a discussion of wave stability and bifurcation as a function of system parameters, including the speed and strength of synaptic coupling and the speed of axonal signals. The theory is illustrated with the construction and stability analysis of front solutions to a scalar neural field model and a limiting case is shown to recover recent results of L. Zhang [On stability of traveling wave solutions in synaptically coupled neuronal networks, Differential and Integral Equations, 16, (2003), pp.513-536.]. Traveling fronts and pulses are considered in more general models possessing either a linear or piecewise constant recovery variable. We establish the stability of coexisting traveling fronts beyond a front bifurcation and consider parameter regimes that support two stable traveling fronts of different speed. Such fronts may be connected and depending on their relative speed the resulting region of activity can widen or contract. The conditions for the contracting case to lead to a pulse solution are established. The stability of pulses is obtained for a variety of examples, in each case confirming a previously conjectured stability result. Finally we show how this theory may be used to describe the dynamic instability of a standing pulse that arises in a model with slow recovery. Numerical simulations show that such an instability can lead to the shedding of a pair of traveling pulses.

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The protein Ezrin, is a member of the ERM family (Ezrin, Radixin and Moesin) that links the F-actin to the plasma membrane. The protein is made of three domains namely the FERM domain, a central α-helical domain and the CERMAD domain. The residues in Ezrin such as Ser66, Tyr145, Tyr353 and Tyr477 regulate the function of the protein through phosphorylation. The protein is found in two distinct conformations of active and dormant (inactive) state. The initial step during the conformation change is the breakage of intramolecular interaction in dormant Ezrin by phosphorylation of residue Thr567. The dormant structure of human Ezrin was predicted computationally since only partial active form structure was available. The validation analysis showed that 99.7% residues were positioned in favored, allowed and generously allowed regions of the Ramachandran plot. The Z-score of Ezrin was −7.36, G-factor was 0.1, and the QMEAN score of the model was 0.61 indicating a good model for human Ezrin. The comparison of the conformations of the activated and dormant Ezrin showed a major shift in the F2 lobe (residues 142-149 and 161-177) while changes in the conformation induced mobility shifts in lobe F3 (residues 261 to 267). The 3D positions of the phosphorylation sites Tyr145, Tyr353, Tyr477, Tyr482 and Thr567 were also located. Using targeted molecular dynamic simulation, the molecular movements during conformational change from active to dormant were visualized. The dormant Ezrin auto-inhibits itself by a head-to-tail interaction of the N-terminal and C-terminal residues. The trajectory shows the breakage of the interactions and mobility of the CERMAD domain away from the FERM domain. Protein docking and clustering analysis were used to predict the residues involved in the interaction between dormant Ezrin and mTOR. Residues Tyr477 and Tyr482 were found to be involved in interaction with mTOR.

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This project posits a link between representations of animals or animality and representations of illness in the Victorian novel, and examines the narrative uses and ideological consequences of such representations. Figurations of animality and illness in Victorian fiction have been examined extensively as distinct phenomena, but examining their connection allows for a more complex view of the role of sympathy in the Victorian novel. The commonplace in novel criticism is that Victorian authors, whether effectively or not, constructed their novels with a view to the expansion of sympathy. This dissertation intervenes in the discussion of the Victorian novel as a vehicle for sympathy by positing that texts and scenes in which representations of illness and animality are conjoined reveal where the novel draws the boundaries of the human, and the often surprising limits it sets on sympathetic feeling. In such moments, textual cues train or direct readerly sympathies in ways that suggest a particular definition of the human, but that direction of sympathy is not always towards an enlarged sympathy, or an enlarged definition of the human. There is an equally (and increasingly) powerful antipathetic impulse in many of these texts, which estranges readerly sympathy from putatively deviant, degenerate, or dangerous groups. These two opposing impulses—the sympathetic and the antipathetic—often coexist in the same novel or even the same scene, creating an ideological and affective friction, and both draw on the same tropes of illness and animality. Examining the intersection of these different discourses—sympathy, illness, and animality-- in these novels reveals the way that major Victorian debates about human nature, evolution and degeneration, and moral responsibility shaped the novels of the era as vehicles for both antipathy and sympathy. Focusing on the novels of the Brontës and Thomas Hardy, this dissertation examines in depth the interconnected ways that representations of animals and animality and representations of illness function in the Victorian novel, as they allow authors to explore or redefine the boundary between the human and the non-human, the boundary between sympathy and antipathy, and the limits of sympathy itself.

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In this paper we consider instabilities of localised solutions in planar neural field firing rate models of Wilson-Cowan or Amari type. Importantly we show that angular perturbations can destabilise spatially localised solutions. For a scalar model with Heaviside firing rate function we calculate symmetric one-bump and ring solutions explicitly and use an Evans function approach to predict the point of instability and the shapes of the dominant growing modes. Our predictions are shown to be in excellent agreement with direct numerical simulations. Moreover, beyond the instability our simulations demonstrate the emergence of multi-bump and labyrinthine patterns. With the addition of spike-frequency adaptation, numerical simulations of the resulting vector model show that it is possible for structures without rotational symmetry, and in particular multi-bumps, to undergo an instability to a rotating wave. We use a general argument, valid for smooth firing rate functions, to establish the conditions necessary to generate such a rotational instability. Numerical continuation of the rotating wave is used to quantify the emergent angular velocity as a bifurcation parameter is varied. Wave stability is found via the numerical evaluation of an associated eigenvalue problem.

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Functional nucleic acids (FNA), including nucleic acids catalysts (ribozymes and DNAzymes) and ligands (aptamers), have been discovered in nature or isolated in a laboratory through a process called in vitro selection. They are nucleic acids with functions similar to protein enzymes or antibodies. They have been developed into sensors with high sensitivity and selectivity; it is realized by converting the reaction catalyzed by a DNAzyme/ribozyme or the binding event of an aptamer to a fluorescent, colorimetric or electrochemical signal. While a number of studies have been reported for in vitro sensing using DNAzymes or aptamers, there are few reports on in vivo sensing or imaging. MRI is a non-invasive imaging technique; smart MRI contrast agents were synthesized for molecular imaging purposes. However, their rational design remains a challenge due to the difficulty to predict molecular interactions. Chapter 2 focuses on rational design of smart T1-weighted MRI contrast agents with high specificity based on DNAzymes and aptamers. It was realized by changing the molecular weight of the gadolinium conjugated DNA strand with the analytes, which lead to analyte-specific water proton relaxation responses and contrast changes on an MRI image. The designs are general; the high selectivity of FNA was retained. Most FNA-based fluorescent sensors require covalent labeling of fluorophore/quencher to FNAs, which incurrs extra expenses and could interfere the function of FNAs. Chapter 3 describes a new sensor design avoiding the covalent labeling of fluorophore and quencher. The fluorescence of malachite green (MG) was regulated by the presence of adenosine. Conjugate of aptamers of MG and adenosine and a bridge strand were annealed in a solution containing MG. The MG aptamer did not bind MG because of its hybridization to the bridge strand, resulting in low fluorescence signal of MG. The hybridization was weakened in the presence of adenosine, leading to the binding of MG to its aptamer and a fluorescence increase. The sensor has comparable detection limit (20 micromolar) and specificity to its labeled derivatives. Enzymatic activity of most DNAzymes requires metal cations. The research on the metal-DNAzyme interaction is of interest and challenge to scientists because of the lack of structural information. Chapters 4 presents the research on the characterization of the interaction between a Cu2+-dependent DNAzyme and Cu2+. Electron paramagnetic resonance (EPR) and UV-Vis spectroscopy were used to probe the binding of Cu2+ to the DNAzyme; circular dichroism was used to probe the conformational change of the DNAzyme induced by Cu2+. It was proposed that the conformational change by the Cu2+ binding is important for the activity of the DNAzyme. Chapter 5 reports the dependence of the activity of 8-17 DNAzyme on the presence of both Pb2+ and other metal cations including Zn2+, Cd2+ and Mg2+. It was discovered that presence of those metal cations can be cooperative or inhibitive to 8-17 activity. It is hypothesized that the 8-17 DNAzyme had multiple binding sites for metal cations based on the results. Cisplatin is effective killing tumor cells, but with significant side effects, which can be minimized by its targeted delivery. Chapter 6 focuses on the effort to functionalize liposomes encapsulating cisplatin by an aptamer that selectively bind nucleolin, an overexpressed protein by breast cancer cells. The study proved the selective cytotoxicity to breast cancer cells of the aptamer-functionalized liposome.

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This dissertation presents work done in the design, modeling, and fabrication of magnetically actuated microrobot legs. Novel fabrication processes for manufacturing multi-material compliant mechanisms have been used to fabricate effective legged robots at both the meso and micro scales, where the meso scale refers to the transition between macro and micro scales. This work discusses the development of a novel mesoscale manufacturing process, Laser Cut Elastomer Refill (LaCER), for prototyping millimeter-scale multi-material compliant mechanisms with elastomer hinges. Additionally discussed is an extension of previous work on the development of a microscale manufacturing process for fabricating micrometer-sale multi-material compliant mechanisms with elastomer hinges, with the added contribution of a method for incorporating magnetic materials for mechanism actuation using externally applied fields. As both of the fabrication processes outlined make significant use of highly compliant elastomer hinges, a fast, accurate modeling method for these hinges was desired for mechanism characterization and design. An analytical model was developed for this purpose, making use of the pseudo rigid-body (PRB) model and extending its utility to hinges with significant stretch component, such as those fabricated from elastomer materials. This model includes 3 springs with stiffnesses relating to material stiffness and hinge geometry, with additional correction factors for aspects particular to common multi-material hinge geometry. This model has been verified against a finite element analysis model (FEA), which in turn was matched to experimental data on mesoscale hinges manufactured using LaCER. These modeling methods have additionally been verified against experimental data from microscale hinges manufactured using the Si/elastomer/magnetics MEMS process. The development of several mechanisms is also discussed: including a mesoscale LaCER-fabricated hexapedal millirobot capable of walking at 2.4 body lengths per second; prototyped mesoscale LaCER-fabricated underactuated legs with asymmetrical features for improved performance; 1 centimeter cubed LaCER-fabricated magnetically-actuated hexapods which use the best-performing underactuated leg design to locomote at up to 10.6 body lengths per second; five microfabricated magnetically actuated single-hinge mechanisms; a 14-hinge, 11-link microfabricated gripper mechanism; a microfabricated robot leg mechansim demonstrated clearing a step height of 100 micrometers; and a 4 mm x 4 mm x 5 mm, 25 mg microfabricated magnetically-actuated hexapod, demonstrated walking at up to 2.25 body lengths per second.

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BACKGROUND: Regional differences in physician supply can be found in many health care systems, regardless of their organizational and financial structure. A theoretical model is developed for the physicians' decision on office allocation, covering demand-side factors and a consumption time function. METHODS: To test the propositions following the theoretical model, generalized linear models were estimated to explain differences in 412 German districts. Various factors found in the literature were included to control for physicians' regional preferences. RESULTS: Evidence in favor of the first three propositions of the theoretical model could be found. Specialists show a stronger association to higher populated districts than GPs. Although indicators for regional preferences are significantly correlated with physician density, their coefficients are not as high as population density. CONCLUSIONS: If regional disparities should be addressed by political actions, the focus should be to counteract those parameters representing physicians' preferences in over- and undersupplied regions.

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Receiving personalised feedback on body mass index and other health risk indicators may prompt behaviour change. Few studies have investigated men’s reactions to receiving objective feedback on such measures and detailed information on physical activity and sedentary time. The aim of my research was to understand the meanings different forms of objective feedback have for overweight/obese men, and to explore whether these varied between groups. Participants took part in Football Fans in Training, a gender-sensitised, weight loss programme delivered via Scottish Professional Football Clubs. Semi-structured interviews were conducted with 28 men, purposively sampled from four clubs to investigate the experiences of men who achieved and did not achieve their 5% weight loss target. Data were analysed using the principles of thematic analysis and interpreted through Self-Determination Theory and sociological understandings of masculinity. Several factors were vital in supporting a ‘motivational climate’ in which men could feel ‘at ease’ and adopt self-regulation strategies: the ‘place’ was described as motivating, whereas the ‘people’ (other men ‘like them’; fieldwork staff; community coaches) provided supportive and facilitative roles. Men who achieved greater weight loss were more likely to describe being motivated as a consequence of receiving information on their objective health risk indicators. They continued using self-monitoring technologies after the programme as it was enjoyable; or they had redefined themselves by integrating new-found activities into their lives and no longer relied on external technologies/feedback. They were more likely to see post-programme feedback as confirmation of success, so long as they could fully interpret the information. Men who did not achieve their 5% weight loss reported no longer being motivated to continue their activity levels or self-monitor them with a pedometer. Social support within the programme appeared more important. These men were also less positive about objective post-programme feedback which confirmed their lack of success and had less utility as a motivational tool. Providing different forms of objective feedback to men within an environment that has intrinsic value (e.g. football club setting) and congruent with common cultural constructions of masculinity, appears more conducive to health behaviour change.

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Ce projet illustre cinq études, mettant l'emphase sur le développement d'une nouvelle approche diagnostique cardiovasculaire afin d'évaluer le niveau d’oxygène contenu dans le myocarde ainsi que sa fonction microvasculaire. En combinant une séquence de résonance magnétique cardiovasculaire (RMC) pouvant détecter le niveau d’oxygène (OS), des manœuvres respiratoires ainsi que des analyses de gaz artériels peuvent être utilisés comme procédure non invasive destinée à induire une réponse vasoactive afin d’évaluer la réserve d'oxygénation, une mesure clé de la fonction vasculaire. Le nombre de tests diagnostiques cardiaques prescrits ainsi que les interventions, sont en pleine expansion. L'imagerie et tests non invasifs sont souvent effectués avant l’utilisation de procédures invasives. L'imagerie cardiaque permet d’évaluer la présence ou absence de sténoses coronaires, un important facteur économique dans notre système de soins de santé. Les techniques d'imagerie non invasives fournissent de l’information précise afin d’identifier la présence et l’emplacement du déficit de perfusion chez les patients présentant des symptômes d'ischémie myocardique. Néanmoins, plusieurs techniques actuelles requièrent la nécessité de radiation, d’agents de contraste ou traceurs, sans oublier des protocoles de stress pharmacologiques ou physiques. L’imagerie RMC peut identifier une sténose coronaire significative sans radiation. De nouvelles tendances d’utilisation de RMC visent à développer des techniques diagnostiques qui ne requièrent aucun facteur de stress pharmacologiques ou d’agents de contraste. L'objectif principal de ce projet était de développer et tester une nouvelle technique diagnostique afin d’évaluer la fonction vasculaire coronarienne en utilisant l' OS-RMC, en combinaison avec des manœuvres respiratoires comme stimulus vasoactif. Ensuite, les objectifs, secondaires étaient d’utilisés l’OS-RMC pour évaluer l'oxygénation du myocarde et la réponse coronaire en présence de gaz artériels altérés. Suite aux manœuvres respiratoires la réponse vasculaire a été validée chez un modèle animal pour ensuite être utilisé chez deux volontaires sains et finalement dans une population de patients atteints de maladies cardiovasculaires. Chez le modèle animal, les manœuvres respiratoires ont pu induire un changement significatif, mesuré intrusivement par débit sanguin coronaire. Il a été démontré qu’en présence d'une sténose coronarienne hémodynamiquement significative, l’OS-RMC pouvait détecter un déficit en oxygène du myocarde. Chez l’homme sain, l'application de cette technique en comparaison avec l'adénosine (l’agent standard) pour induire une vasodilatation coronarienne et les manœuvres respiratoires ont pu induire une réponse plus significative en oxygénation dans un myocarde sain. Finalement, nous avons utilisé les manœuvres respiratoires parmi un groupe de patients atteint de maladies coronariennes. Leurs myocardes étant altérées par une sténose coronaire, en conséquence modifiant ainsi leur réponse en oxygénation. Par la suite nous avons évalué les effets des gaz artériels sanguins sur l'oxygénation du myocarde. Ils démontrent que la réponse coronarienne est atténuée au cours de l’hyperoxie, suite à un stimuli d’apnée. Ce phénomène provoque une réduction globale du débit sanguin coronaire et un déficit d'oxygénation dans le modèle animal ayant une sténose lorsqu’un supplément en oxygène est donné. En conclusion, ce travail a permis d'améliorer notre compréhension des nouvelles techniques diagnostiques en imagerie cardiovasculaire. Par ailleurs, nous avons démontré que la combinaison de manœuvres respiratoires et l’imagerie OS-RMC peut fournir une méthode non-invasive et rentable pour évaluer la fonction vasculaire coronarienne régionale et globale.

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Bioactive extracts were obtained from powdered carob pulp through an ultrasound extraction process and then evaluated in terms of antioxidant activity. Ten minutes of ultrasonication at 375 Hz were the optimal conditions leading to an extract with the highest antioxidant effects. After its chemical characterization, which revealed the preponderance of gallotannins, the extract (free and microencapsulated) was incorporated in yogurts. The microspheres were prepared using an extract/sodium alginate ratio of 100/400 (mg mg(-1)) selected after testing different ratios. The yogurts with the free extract exhibited higher antioxidant activity than the samples added with the encapsulated extracts, showing the preserving role of alginate as a coating material. None of the forms significantly altered the yogurt's nutritional value. This study confirmed the efficiency of microencapsulation to stabilize functional ingredients in food matrices maintaining almost the structural integrity of polyphenols extracted from carob pulp and furthermore improving the antioxidant potency of the final product.

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In order to evaluate the impact of the alkyl side chain length and symmetry of the cation on the thermophysical properties of water-saturated ionic liquids (ILs), densities and viscosities as a function of temperature were measured at atmospheric pressure and in the (298.15 to 363.15) K temperature range, for systems containing two series of bis(trifluoromethylsulfonyl)imide-based compounds: the symmetric [C n C n im][NTf2] (with n = 1-8 and 10) and asymmetric [C n C1im][NTf2] (with n = 2-5, 7, 9 and 11) ILs. For water-saturated ILs, the density decreases with the increase of the alkyl side chain length while the viscosity increases with the size of the aliphatic tails. The saturation water solubility in each IL was further estimated with a reasonable agreement based on the densities of water-saturated ILs, further confirming that for the ILs investigated the volumetric mixing properties of ILs and water follow a near ideal behaviour. The water-saturated symmetric ILs generally present lower densities and viscosities than their asymmetric counterparts. From the experimental data, the isobaric thermal expansion coefficient and energy barrier were also estimated. A close correlation between the difference in the energy barrier values between the water-saturated and pure ILs and the water content in each IL was found, supporting that the decrease in the viscosity of ILs in presence of water is directly related with the decrease of the energy barrier.

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Since its identification in the 1990s, the RNA interference (RNAi) pathway has proven extremely useful in elucidating the function of proteins in the context of cells and even whole organisms. In particular, this sequence-specific and powerful loss-of-function approach has greatly simplified the study of the role of host cell factors implicated in the life cycle of viruses. Here, we detail the RNAi method we have developed and used to specifically knock down the expression of ezrin, an actin binding protein that was identified by yeast two-hybrid screening to interact with the Severe Acute Respiratory Syndrome Coronavirus (SARS-CoV) spike (S) protein. This method was used to study the role of ezrin, specifically during the entry stage of SARS-CoV infection.

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Investors value the special attributes of monetary assets (e.g., exchangeability, liquidity, and safety) and pay a premium for holding them in the form of a lower return rate -- The user cost of holding monetary assets can be measured approximately by the difference between the returns on illiquid risky assets and those of safer liquid assets -- A more appropriate measure should adjust this difference by the differential risk of the assets in question -- We investigate the impact that time non-separable preferences has on the estimation of the risk-adjusted user cost of money -- Using U.K. data from 1965Q1 to 2011Q1, we estimate a habit-based asset pricing model with money in the utility function and find that the risk adjustment for risky monetary assets is negligible -- Thus, researchers can dispense with risk adjusting the user cost of money in constructing monetary aggregate indexes