VictorJuiz/thesis huggingface dataset:
Cellular and molecular mechanisms of N-methyl-D-aspartate receptor mediated calcium-dependent neurotoxicity in cortical cell cultures

The N-methyl-D-aspartate receptors (NMDARs) have been ascribed a key role in excitotoxicity owing to their ubiquitous distribution in central neurons, and to their high permeability to Calcium (Ca2+) ions. NMDAR overactivation was thought to trigger excitotoxicity by excessive intracellular Ca2+ accumulation that exceeds the cell's regulatory capacity. Here, we established that the chief determinant of Ca2+ neurotoxicity is the route of Ca2+ entry, and not the total Ca2+ load. Whereas neurons were rapidly damaged when loaded with Ca2+ ions through NMDARs, a similar Ca2+ load incurred through alternative pathways, such as voltage sensitive calcium channels (VSCCs), was innocuous. First, we investigated whether it is the synaptic localization of NMDARs that is responsible for the toxic potential of NMDAR-mediated Ca2+ loading. Perturbing F-actin, a cytoskeletal protein that participates in targeting synaptic NMDARs in dendritic spines, reduced the number of dendritic NMDAR clusters and the NMDAR-mediated component of spontaneous miniature EPSCs, while the AMPA receptor-mediated component was unchanged. This selective perturbation of synaptic NMDARs had no effect on neuronal death or the accumulation of 45Ca2+ evoked by applying exogenous NMDA, which reaches both synaptic and extrasynaptic receptors. However, it increased survival and decreased 45Ca2+ accumulation in neurons exposed to oxygen-glucose deprivation, which causes excitotoxicity by synaptic glutamate release, and causes toxicity mainly by activation of synaptic receptors. Thus, it is not the synaptic localization of the NMDARs that determines their toxic potential. We next examined whether the association of NMDARs with distinct membrane-associated macromolecular complexes initiate and/or propagate neurotoxic Ca2+ signaling. We studied excitotoxic NMDAR signaling by suppressing the expression of the NMDAR scaffolding protein PSD-95, which selectively attenuated excitotoxicity triggered via NMDARs, but not by other glutamate or Ca2+ channels. NMDAR function was unaffected, as receptor expression, NMDA-currents and 45Ca2+ loading via NMDARs were unchanged. Suppressing PSD-95 selectively blocked Ca 2+-activated nitric oxide production by NMDARs, but not by other pathways, without affecting neuronal nitric oxide synthase (nNOS) expression or function. Thus, PSD-95 is required for the efficient coupling of NMDAR activity to nitric oxide toxicity, and imparts specificity to NMDAR-mediated excitotoxic Ca 2+ signaling.
Perspectives on place in education

This thesis explores the philosophical role of 'place' in contextualizing educational reform throughout the 20th century. It is argued that educational reform movements can be understood in terms of how they construct and reconstruct the geographical and ideological landscapes of education. The thesis begins with a general introduction to the study of place in education, focusing particularly on the role of ideology and developmentalism in the study of education and place respectively. Subsequent chapters then integrate these two foci by contrasting the different ways in which a number of educational reform movements have organized classrooms and other learning spaces throughout the 20th century. Until the mid-1960s, all reform movements by definition were committed to the physical construction of learning spaces, but with the rise of the cyberschooling movement, a new focus on virtual learning places has now taken hold. A latter chapter of the thesis examines the cyberschooling agenda for education from the vantage point of place. A concluding chapter considers how changing societal and technological conditions could impact on the future of place in education.
Search for BFKL evolution using forward jets in deep inelastic scattering at HERA

The inclusive jet cross section in deep inelastic 'ep' scattering, at low Bjorken 'x', was measured in the forward region of the ZEUS detector at HERA. This measurement is expected to be sensitive to the differences between the DGLAP and BFKL parton evolution equations, and is examined to see if BFKL evolution can be observed at HERA. Leading order perturbative QCD calculations at the parton level for BFKL evolution predicts an excess of forward jet production at small 'x' over DGLAP predictions. From 6.36 pb-1 of data collected in 1995, the cone jet finder was used to identify jets within the range of Bjorken ' x' of 4.5 · 10-4 to 4.5 · 10 -2, 'ET' > 5 GeV, and with a polar angle to the proton direction of [theta]'jet' > 8.5°. The forward jet cross section at the hadron level as a function of 'x' is compared to predictions from various Monte Carlo models. A steep rise in the forward low 'x' jet cross section is observed. This is consistent with the expectations of BFKL evolution, and agrees with results based on the Colour Dipole model, which has some similarities to BFKL. Predictions based on the DGLAP equations fail to describe the data, except when resolved photon contributions are included. These give good agreement to the data, and provide an alternative explanation for the results without relying on BFKL evolution.
Dynamics of the Wyman sector in the Nonsymmetric Gravitational Theory

The canonical analysis of Nonsymmetric Gravitational Theory ( NGT) is reviewed in order to provide a framework with which to examine the dynamics of the theory. This study is simplified by considering the dynamics of the Wyman sector in spherical symmetry, which is compared to the dynamics of a self-gravitating scalar field (EKG). The similarity between the two theories allows us to use the singularity theorems of General Relativity (GR) in order to equate the existence of trapped surfaces on a spacelike hypersurface with the formation of a black hole region in the spacetime. The stability of the static spherically symmetric solutions of both NGT and EKG is discussed. It is found that the Wyman solution of NGT is unstable against spherically symmetric perturbations, which excludes this as a possible endstate of a generic evolution. Furthermore, it is demonstrated that the only possible solution in NGT which is globally regular is the Minkowski solution, while the only solution with an event horizon is the Schwarzschild solution. These solutions, which are shown to be perturbatively stable, can represent such an endstate. Meanwhile, it is demonstrated that the corresponding solutions in EKG have both a stable and an unstable branch, and due to their nakedly singular nature might have implications for the Cosmic Censorship Conjecture. Finally, the spherically symmetric Wyman field equations are numerically integrated. The initial data is chosen to consist of a spherically symmetric pulse in the Wyman sector, and the results are compared to the evolution of a scalar field. In particular, it is shown that an apparent horizon does indeed form for "strong" enough initial data, and critical behaviour is observed at the threshold of black hole formation.
Female sexual abuse of children, an exploratory study

The purpose of this research was to explore the phenomenon of female sexual abuse of children, and to examine the usefulness of Finkelhor's Four-Preconditions Model of Sexual Abuse in determining factors related to this abuse. This study investigated whether women commit sexual offences against children for different reasons than men and whether female sexual offenders possess cognitive distortions about sexual contact with children. Results collected from a sample of thirty female sexual offenders recruited for the study are presented in qualitative and quantitative format. Findings from the study suggested that female sexual offenders are not a homogeneous group and cannot be studied as such. Approximately half of this sample of sex offenders were forced to abuse their victims by their male partners or husbands, a powerful finding from the study, and a replicated finding from previous research. The research also revealed that almost three-quarters of the women in this study were the victims of sexual abuse themselves when they were younger. This is a higher percentage than found for male child sexual offenders. Findings also suggest that, unlike male sex offenders, female sexual offenders did not appear to endorse cognitive distortions that contribute to child sexual abuse. Despite the comprehensiveness of the model in terms of its explanatory power for the behaviour of male sex offenders, it fails as an overall model when applied to a sample of female sex offenders. The model is only partially useful when applied to a particular sub-group of women who sexually abuse children; that is, the small number of women who can be described as most closely fitting the profile of a pedophile. Given the heterogeneity of female sex offenders, the model is limited in terms of providing guidance for a conceptual analysis of women who sexually abuse children. To its credit, the model has been a useful organizing tool with respect to examining the numerous facets and complexities behind the behaviour of women who sexually abuse children.
Tornado, maximizing locality and concurrency in a shared-memory multiprocessor operating system

This dissertation presents novel operating system structuring techniques for dealing with the problems of scalability in shared-memory multiprocessors. By using an object-oriented structure, with each virtual and physical resource represented by an independent object, Tornado eliminates most shared global objects, thus reducing contention and increasing locality. To improve performance for contended components, Tornado uses a new structuring technique called ' Clustered Objects' that allows an object to be partitioned and distributed across the machine in a manner transparent to the outside consumers of the object. In addition, Tornado includes a new interprocess communication facility, called the 'Protected Procedure Call' facility, that provides the locality and concurrency required to allow microkernels to scale effectively on multiprocessors. This dissertation also explores some of the other issues in multiprocessor operating system design, such as efficient lock and memory allocation implementations, as well as the interactions between concurrency control and object destruction. A prototype implementation of the techniques described have been implemented as part of the Tornado operating system for the NUMAchine multiprocessor. This dissertation explores both the design aspects of the system as well as experiences gained through its implementation and use on both NUMAchine and a complete machine simulator, SimOS.
Implementing evidence-based guidelines for x-ray use in acute low back pain: A pilot study in a chiropractic community

'Objective'. To evaluate the ability of a systematic educational intervention strategy in changing the x-ray ordering behaviour of chiropractors, for patients with acute low back pain (ALBP), towards evidence-based practice. 'Design'. A quasi-experimental method was used comparing outcomes before and after the intervention with that of a control community. 'Setting'. Two communities in southern Ontario. 'Data source'. Mailed survey data on the management of ALBP. 'Outcome measures'. The x-ray use rates for ALBP based on responses to mailed surveys. 'Results'. Following the intervention there was a significant reduction in x-ray use for uncomplicated ALBP (p < 0.025) and for patients with ALBP < 1 month (p < 0.025) in the intervention community. There was no significant change in x-ray use in the control community (p > 0.05). 'Conclusions'. The educational intervention strategy used in this study appeared to have an effect in reducing the perceived need for x-ray use in ALBP.
Society and ideology in Valle-Inclan's Jardin umbrío

This thesis is dedicated to analyzing the ideologies of the society depicted in the seventeen short stories collected in Valle-Inclán's ' Jardín umbrío'. All these stories take place in the province of Galicia, an isolated area of Spain. So that we may understand Galicia's social, economic, and political condition, the first chapter offers an analysis of these particular aspects of nineteenth-century Galicia. The thesis will explore the meaning and theory of ideology in light of the theories proposed by writers such as Althusser, Barbéris, and Eagleton. This thesis utilizes Eagleton's methodology set out in his book 'Criticism and Ideology' in which he provides terms for identifying different types of ideology. In Chapters Four and Five I use these terms to classify the ideologies found in these seventeen short stories. Chapter Four focuses on the ideologies of Carlism found, for example, in the short story "Un cabecilla" and feudalism, found in "Mi bisabuelo" and their role in nineteenth-century Galician society. This society is still operating under the Antigno Régimen, even though liberalism had already made inroads in Spanish politics. Because of its isolation Galicia hardly felt the impact of liberalism nor did industrialism leave much impression on Galicia. As we find in "Mi bisabuelo", the middle-class, personified in the clerk Malvido, had no place in Galician rural society. Furthermore, the middle-class was regarded with hostility by the rural peasants. Chapter Five focuses on religion and superstition practised by the Galician people. Although the Catholic Church reigned supreme in Spain, the Galician people were also influenced by the superstitions of their region. We find that both Catholicism and superstition were inextricably bound together. This can be seen particularly in "Beatriz", "Del misterio", and "Mi hermana Antonia". From the analysis of these ideologies encountered in the short stories of 'Jardín umbrío', we gain a sense of nineteenth-century Galicia according to Valle-Inclán who uses these stories to showcase his feelings of frustration, bitterness and resentment of Galicia's political, economic, and religious situation at the end of the nineteenth century.
The Lasso and its implementation for neural networks

Choosing the architecture of a neural network is one of the most important problems in making neural networks practically useful. How many hidden units are needed, should shrinkage be used, and if so how much? This thesis proposes Lasso neural network models and algorithms for fitting models based on feed-forward neural networks. Lasso neural network models select the architecture of the neural network in the process of estimating its parameters. These models employ both the Lasso style constraint and the idea of hyperparameters of the ARD model, and combine them in a manner that preserves the Lasso's advantage of shrinking some parameters to exactly zero and the hyperparameter's advantage of controlling the magnitudes of predictors and/or hidden units. We also prove that in linear models, the Lasso solution function is a linear spline in terms of the shrinkage parameter, and derive the closed forms of the sub-functions of this spline. Accordingly, we propose a quasi-analytic algorithm for solving the Lasso solutions in linear models. Since the Lasso solutions are equivalent to their Ridge- modified version, the more accurate Ridge-modified GCV scores for Lasso solutions can be obtained by the quasi-analytic algorithm.
Influence of DC saddle-field discharge deposition parameters on the structure of hydrogenated amorphous carbon semiconductor

Thin hydrogenated amorphous carbon (a-C:H) films were grown using an innovative deposition system, the DC saddle-field discharge. The properties of a-C:H films and the dependence of their properties on the growth conditions have been investigated. The study of deposition conditions has led to a better understanding of the deposition processes in the DC saddle-field discharge. This has ensured a greater degree of control of the properties of a-C:H films grown using the system, leading to the growth of a wide variety of films whose properties included those of a-C:H films described in literature. The basic DC saddle-field discharge mechanisms have been analysed with the help of a standard DC discharge model. The effect on the discharge conditions of the semitransparency of the electrodes has been characterized. When the DC saddle-field discharge is used as a deposition system for thin films such as hydrogenated amorphous carbon films, it has been shown that this deposition system allows for independent control of two parameters critical in the growth of thin films, the ion energy and the density of the ions reaching the substrate. In the DC saddle-field discharge, the range of combinations of the ion density and the energy of ions reaching the substrate is greatly extended, in comparison to the standard DC deposition system. The study of a-C:H film growth as a function of the energy and density of ions incident on the growing surface has led to an understanding of the a-C:H growth mechanisms and the parameters which influence these mechanisms. The presence of both sp3 and sp2 bonds in a-C:H is responsible for the wide range of properties of this material. However, this diversity of bonding configurations results in a complex interpretation of the electronic structure and the chemical bonding of a-C:H. The analysis of optical measurements performed on a set of a-C:H films has confirmed the model proposed by Robertson where the sp2 content controls the Tauc energy gap. However, a better understanding of the change in the structure of the films has now been reached. The change from wide band gap films (2.2 eV) to narrow band gap films (1.2 eV) is matched by an important structural change. Through this analysis, trends in the complex a-C:H bond distributions have been related to optical properties of the film. The important properties of a-C:H, such as Tauc energy gap and hydrogen content, have also been related to plasma behaviour through deposition parameters.
Time, truth and realism, an essay on the semantics and metaphysics of tense

Different beliefs concerning the metaphysical status of ' tense' divide philosophers into two camps. Those who embrace a ' tensed' theory of time (often called the 'A-series') argue that 'past', 'present' and 'future' correspond to genuine ontological distinctions. Those who deny the reality of such distinctions espouse a tenseless theory of time (known as the 'B-series'). In this essay I defend a tenseless account. I begin with an examination of the most prominent ontological conceptions of tense, finding them to be incoherent at worst, highly implausible at best. I then turn my attention to Einstein's Special Theory of Relativity, arguing that, properly understood, it demonstrates that tenses could not be physically realized. The upshot is that tense is not a philosophically viable notion. If time is real, it must be tenseless. Therefore, the choice is between tenseless time and some sort of temporal idealism. Defending the former alternative, I focus my efforts, in the second part of the essay, on responding to the most important objections to a tense-free ontology. I argue that tenseless time: (1) can explain the semantics of tensed sentences; (2) does not entail fatalism or determinism of any kind; and (3) is consistent with our mental experience. These results indicate that tense is a feature of perception, not a property of time itself. In the third part of the essay I argue that theories that constrain ' truth' epistemically are poorly motivated and implausible. Therefore, in considering the status of tense, ontological considerations can rightly take precedence over epistemic concerns. This defuses objections to tenseless time that are based on the obvious fact that the past, present and future differ with respect to their epistemic accessibility. It is, therefore, consistent to hold that time is epistemically asymmetric but ontologically symmetric.
Clinical utility of quantitative cytomegalovirus viral load determination for predicting cytomegalovirus disease in liver transplant recipients

The early detection of cytomegalovirus (CMV) reactivation after liver transplantation may form the basis of a pre-emptive strategy for prevention of active CMV disease. We prospectively analyzed the clinical utility of weekly CMV plasma viral load determinations by quantitative PCR and the antigenemia assay in predicting CMV disease in 97 liver transplant recipients. CMV disease occurred in 21/97 (21.7%) patients a mean of 60 days post-transplant. Using a threshold of >400 copies/ml plasma, PCR had a sensitivity of 100%, specificity 47.4%, positive predictive value (PPV) 34.4% and negative predictive value (NPV) 100% for prediction of CMV disease. Respective values for a positive antigenemia (threshold >0 positive cells per 150,000 examined) were 95.2%, 55.3%, 37.0% and 97.7%. Different cut-off points for a positive test were analyzed using receiver-operating characteristic curves. The optimal cut-off for viral load was in the range of 2000-5000 copies/ml (sensitivity 85.7%, specificity 86.8%, PPV 64.3%, NPV 95.7% for >5000 copies/ml). The optimal cut-off for antigenemia was in the range of 4-6 positive cells/slide. Mean peak viral load in symptomatic patients was 73,715 copies per/ml compared to 3615 copies/ml in patients with asymptomatic CMV reactivation (p < 0.001). In a multivariate logistic regression analysis of risk factors for CMV disease (CMV serostatus, acute rejection, and induction immunosuppression), peak viral load and peak antigenemia emerged as the only significant independent predictors of CMV disease (for PCR, OR = 1.40 per 1000 copy/ml increase in viral load, p = 0.0001; for antigenernia OR = 1.17 per 1 positive cell/slide). Plasma viral load by quantitative PCR is a useful test for predicting CMV disease, is at least as sensitive and specific as antigenemia, and could be employed as a marker in a pre-emptive strategy.