Дисертації з теми "62P12"

Cette thèse porte sur l'utilisation de méthodes de post-traitement statistiques dans le but d'améliorer les prévisions d'ensemble. Les prévisions d'ensemble sont des prévisions composées de différents membres dont la diversité tente de capturer l'incertitude liée à la prédiction. Les prévisions d'ensemble souffrent de biais et de sous-dispersion et un post-traitement est donc nécessaire afin d'améliorer leur performance. D'un point de vue théorique, cette thèse apporte des résultats sur le taux de convergence en régression distributionnelle en termes de continuous ranked probability score. De nombreuses méthodes de post-traitement statistiques établies tombent dans le cadre théorique de ce résultat. Par ailleurs, dans le cadre de la collaboration avec Météo-France, une méthode de post-traitement statistique basée sur un réseau de neurones U-Net a été développée afin de remédier aux limitations des méthodes utilisées opérationnellement lors de l'utilisation de données sous forme de grille. Cette thèse propose également la construction de scoring rules propres basées sur l'agrégation et la transformation afin de faciliter la vérification de prévisions probabilistes dans le cas multivarié.En parallèle de la thématique principale de cette thèse, des travaux portant sur la convergence universelle en régression distributionnelle et sur l'utilisation de méthodes de régression distributionnelle pour prédire le risque de récurrence de cancer du sein ont été conduits
This thesis focuses on the use of statistical postprocessing methods to improve ensemble forecasts. Ensemble forecasts are composed of different members whose diversity attempts to capture forecast uncertainties. Ensemble forecasts suffer from bias and underdispersion, and postprocessing is therefore necessary to improve their performance. From a theoretical point of view, this thesis provides rates of convergence for distributional regression in terms of continuous ranked probability score. Numerous well-established statistical post-processing methods fall within the theoretical framework of this result. Furthermore, in collaboration with Météo-France, a statistical postprocessing method based on a U-Net neural network has been developed to overcome the limitations of the methods used operationally when using gridded data. This thesis also proposes the construction of proper scoring rules based on aggregation and transformation to facilitate the verification of probabilistic forecasts in multivariate settings.In parallel with the main theme of this thesis, work has been carried out on universal convergence in distributional regression and on the use of distributional regression methods to predict breast cancer recurrence risk

Hypothalamic tanycytes are a specialised type of glial cell found lining the 3rd ventricle. They possess a cell body that contacts the cerebrospinal fluid (CSF) and a single long process that projects into the hypothalamic parenchyma, some of which are known to extend into the Arcuate nucleus (ARC) and Ventromedial nucleus (VMN), two key hypothalamic regions involved in control of energy homeostasis. Owing to their unique position, it has been hypothesised that hypothalamic tanycytes may be able to detect nutrient related signals in the CSF and influence the neurons of the ARC and VMN leading to changes in food intake and body weight. Tanycytes have recently been shown to be glucosensitive, responding to brief application of glucose by generating Ca2+ waves. However the signalling pathways inducing this response remain elusive. Here we investigated the nature of tanycyte glucosensing. Using Ca2+ imaging techniques we show that tanycytes can respond to glucose and non-nutritive sweeteners implicating the sweet taste receptor as the mediator of tanycyte glucosensitivity. We further show that activation of the sweet taste receptor induces release of ATP from tanycytes via pannexin hemichannels allowing propagation of the Ca2+wave. In addition we also investigated whether hypothalamic tanycytes can communicate to secondary cells within the hypothalamus. Using multiphoton stimulation of a single tanycyte, we show that Ca2+ waves can be generated, which spread between neighbouring cells as well as along the tanycyte process towards the hypothalamic parenchyma. We also demonstrate signalling in secondary cells following tanycyte stimulation is likely the result of tanycyte communication. Thus hypothalamic tanycytes are able to detect sweet tasting compounds in the CSF via the sweet taste receptor, this induces Ca2+ signalling which may be communicated to secondary cells, including the neurons of the ARC and VMN, where it may be integrated to induce changes in energy homeostasis.

The design and proper operation on the above-ground drainage systems can be challenging in a densely populated city like Hong Kong. Discharge loading imposed to a single vertical stack can be large enough that those systems without a proper design, installation or maintenance would suffer problems such as backflow of foul water, contaminated foul air, or even soil waste to the sanitary fitments at lower floors. Any of these nuisances can be regarded as failure because the soil and waste water cannot be properly disposed away from a building. The risk of such a failure would be higher in densely occupied tall buildings. SARS outbreak in 2003 revealed that the consequence of failing to properly manage the drainage system can be as serious as a fatal disaster. The contaminated aerosols, with water droplets with the microorganisms are fatal to human like the SARS virus since it will flow back to the living environment. This research aims at proposing advanced design and monitoring practices upon the drainage system and its components, to minimize the risk of failure and nuisances occurrence. A brief review on several types of failure will be gone through. Besides, a simulation model has been established to predict the air pressure in drainage system. The result will be compared with those from real 1:1 test-rig experiments. This assists the development of innovative inventions of system components such as 8S twin drainage stack which is designed to self-balance air pressure generated by falling water discharge in drainage stack. It ensures better protection of water seal in traps. Smart trap is available to enlarge retention time of water seal due to evaporation. Regarding the management of existing installed drainage system, a protocol has been proposed to troubleshoot the nuisances. It includes remote-control air pressure monitoring and statistical analysis with the development of probability density functions to decide future remedial engineering measures. All of these are integrated as a risk management model aimed to reduce the risk of occurrence of the nuisances.

Dissolved organic matter (DOM) including carbon and nitrogen (DOC and DON) are important but poorly understood components of the marine biogeochemical cycle. In this study, the distribution and cycling of DOC and DON, and particulate organic carbon and nitrogen (POC and PON) were investigated in North Sea surface and bottom water during the stratified summer season in 2011 and 2012, along with other key biogeochemical parameters such as nutrients. The summer DOC, DON, POC and PON ranged from 32.7-134.5, 2.8-13.7, 1.1-43.8 and 0.3-5.9 μM, respectively. The well-mixed water of the southern North Sea was also surveyed in the winter of 2011; measured concentration of DOC and DON were 56.2-224.8 and 3.7-12.3 μM. In summer, DOM and POM generally exhibited high levels in the southern well-mixed water (SM), whereas inorganic nutrient concentrations were higher in the northern bottom water (NB) due to nutrient regeneration and offshore water inflow. DOM in summer and inorganic nutrients in winter were also clearly influenced by riverine inputs. DON was the dominant nitrogen fraction of northern surface water and SM in summer, while in NB, TOxN (nitrate + nitrite) was the dominant fraction. Analysis of SmartBuoy samples show phytoplankton provided a net source of DOM over the spring bloom period with net degradation in autumn and winter. Incubation experiments on water collected from two North Sea sites in autumn, winter 2013 and spring 2014 showed no nutrient (N and P) limitation on DOM degradation. The experiments yield mean bacterial decay rate constants (for three seasons) at the two sites of 4 ± 8 and 2 ± 3 %d-1 kDOC and 3 ± 4 and 4 ± 4 %d-1 kDON, under dark conditions. In comparison to the Redfield ratio, the bulk C:N molar ratio is enriched in carbon relative to nitrogen, while the slope C:N ratio is close to the Redfield ratio, but with a background of high C:N material.

This research explores the value of analytic autoethnography to develop the lecturer’s use of self when teaching mental health nursing. Sharing the lecturer’s selfunderstanding developed through analytic reflexivity focused on their autoethnographic narrative offers a pedagogical approach to contribute to the nursing profession’s policy drive to increase the use of reflective practices. The research design required me to develop my own analytic autoethnography. Four themes emerged from the data ‘Being in between’, ‘Perceived vulnerability of self’, ‘Knowing and doing’, and ‘Uniting selves’. A methodological analysis of the processes involved in undertaking my analytic autoethnography raised issues pertaining to the timing and health warnings of exploring memory as data. Actor-Network Theory was used as an evaluative framework to reposition the research findings back into relationships which support educational practices. The conclusion supports the use of analytic autoethnography to enable lecturers to share hidden practices which underpin the use of self within professional identities. Recommendations seek methodological literature which makes explicit possible emotional reactions to the reconstruction of self through analysis of memories. Being able to share narratives offers a pedagogical approach based on the dilemmas and tensions of being human, bridging the humanity between service user, student and lecturer.

Cyprus’ accession into the Eurozone has been a cornerstone on the modern history of the island. The research project is concentrating on the effect that Cyprus’ participation in the Euro Area will have on the banking and financial institutions. The new Euro Area environment is characterized by “price stability” and that is achieved through an interest rate mechanism set by the European Central Bank. The interest rate levels however, are not disbursed uniformly within each member state. It was identified quite early in the research project that a number of factors are affecting the depositors and borrowers characteristics. Factors such as risk exposure, disposable income, alternative financing sources, average firm size, banking market concentration, asset and liability structure differ from one member state to another. For a banking institution, these particular factors, are enough to deviate from the interest rate benchmark that the European Central Bank is setting, in order to operate efficiently and profitable within each member state’s economic characteristics. The research project was concentrated on the level of the interest rates that exist between the different deposit and loan type products in the Cypriot economy and in the Euro Area. Involving case description general analytic strategies, results were produced from the description of the Euro Area and Cypriot economies, the Euro Area MFIs against Cypriot banks and also at the end the Creek banks against the Cypriot banks. It was proved that during this transition period, there exists disequilibrium on the level of the interest rates between the Cypriot banks, the Euro Area MFIs and the Greek banks. It is also proved that these differences on the level of the interest rates are in favour of the Cypriot banks.

In Sri Lanka, two thirds of the land mass lies within the Dry Zone where agriculture is the most important economic activity. In this climatic zone, rainfall is highly uncertain, seasonal, and limited to a few months. Consequently, the farmers in the area have to face drought as a natural hazard. This study focusses on how the farmers in the southern Dry Zone of Sri Lanka perceive drought as a hazard, the adjustments they make to reduce their vulnerability to droughts and how human behaviour affects the growing hazardousness of the study area. The results of this study show that the farmers in the study area have perceived drought as one of their major problems, and that the vulnerability to this natural phenomenon is growing as a result of the power abuse and environmental mismanagement of those high ranking people responsible. However, the farmers’ deeper understanding regarding their living environment (natural and man-made) has enhanced their power to combat the hazardous effects of droughts by way of a variety of adjustments. Considering and studying the above problems and issues the researcher has come to some conclusions and has put forward some suggestions, the most important of which, lie with changing the self-centered attitudes and activities of the powerful people in the direction of a socially and environmentally more sustainable and wholesome path.

Aims. This thesis aimed to investigate the relationships between social problem-solving, defeat, entrapment and other cognitive risk factors (rumination, goal adjustment) for suicidal ideation and behaviour. The investigation was carried out using the framework of the Integrated Motivational-Volitional Model of Suicidal Behaviour (IMV; O’Connor, 2011) and this thesis aimed to test aspects of this theoretical model. In addition, this thesis also aimed to critically evaluate the measures of social problem-solving employed in suicide research. Method. Five empirical studies across five chapters were conducted. In order to achieve the study’s aims, a systematic review was conducted first which informed the selection of the social problem-solving measures employed within the thesis (Chapter 3). The review also identified the need to update the original Means End Problem-Solving task (MEPS; Platt and Spivack, 1975). A series of focus groups were conducted to revise and update the measure (Chapter 6), two studies were then conducted to test the revised measure (MEPS-R; Chapter 7). A further two studies investigated the relationship between social problem-solving and suicidal ideation and behaviour. The first empirical study was prospective (Chapter 5) and the second was experimental in design (Chapter 8). All studies employed both student and general population samples. Results. The Social Problem-Solving Inventory (SPSI-R; D’Zurilla, et al, 2002) and the MEPS were identified as the most common measures employed in suicide research (Chapter 3). The SPSI-R was employed in all studies and the original MEPS was revised and tested. The MEPS-R was found to be a reliable measure, both inter-rater and internal consistency were good although the MEPS-R scores did not correlate with established risk factors of psychological distress (Chapter 7). However, in the experimental study the MEPS-R was found to correlate with psychological distress (Chapter 8). Dysfunctional social problem-solving was found to be the most pernicious of the SPSI-R subscales and individuals who reported a history of self-harm were found to score higher in dysfunctional problem-solving than individuals who reported no history of self-harm (Chapter 5 and 8). Dysfunctional social problem-solving was found to mediated the defeat-entrapment relationship and rational problem-solving moderate this relationship. Defeat had no discernible impact on social problem-solving performance (Chapter 8). Conclusion. This research makes a novel contribution to the understanding of the relationships between social problem-solving, defeat, entrapment, rumination, goal adjustment and suicidal ideation/behaviour. It also highlights the importance of the dysfunctional aspect of social problem-solving. The IMV model was a useful framework for understanding these relationships. In addition, the revised MEPS (MEPS-R) is a reliable measure of social problem-solving, which is more applicable for use in today’s society but it requires further testing, especially in clinical populations.

Este estudio tiene el fin de investigar la problemática en salud de intoxicaciones por infusiones caseras en lactantes y niños de la primera infancia. El trabajo se realiza en el Centro de Salud Nº 197, El Algarrobo, ubicado en loteo Dante s/n del departamento de Tunuyán. Los objetivos del trabajo son: determinar los factores socioculturales que están provocando el ingreso de niños con intoxicación por infusiones caseras, conocer los factores de riesgo de los niños que ingresan por la intoxicación de infusiones caseras, determinar costumbres sanitarias de la población en juego, ante las necesidades de salud y determinar la información que proporciona el profesional de enfermería a las madres de menores de un año sobre los posibles efectos tóxicos del anís estrellado y manzanilla en el Sistema Respiratorio del niño.
Fil: Cano, Mabel. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Escuela de Enfermería..
Fil: Ciancia, Matilde. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas. Escuela de Enfermería..

Scheduling Theory studies planning and timetabling of various industrial and human activities and, therefore, is of constant scientific interest. Being a branch of Operational Research, Theory of Scheduling mostly deals with problems of practical interest which can be easily (from a mathematical point of view) solved by full enumeration and at the same time usually require enormous time to be solved optimally. Therefore, one attempts to develop algorithms for finding optimal or near optimal solutions of the problems under consideration in reasonable time. If the output of an algorithm is not always an optimal solution then the worst-case analysis of this algorithm is undertaken in order to estimate either a relative error or an absolute error that holds for any given instance of the problem. Scheduling problems which are usually considered in the literature assume that the processing facilities are constantly available throughout the planning period. However, in practice, the processing facility, e.g. a machine, a labour, etc. can become non-available due to various reasons, e.g. breakdowns, lunch breaks, holidays, maintenance work, etc. All these facts stimulate research in the area of scheduling with non-availability constraints. This branch of Scheduling Theory has recently received a lot of attention and a considerable number of research papers have been published. This thesis is fully dedicated to scheduling with non-availability constraints under various assumptions on the structure of the processing system and on the types of non-availability intervals.

Oltre alla progressiva perdita dei linfociti T CD4, i pazienti HIV-infetti presentano diverse citopenie periferiche. In particolare l’anemia si riscontra nel 10% dei pazienti asintomatici e nel 92% di quelli con AIDS e la terapia cART non è in grado di risolvere tale problematica. I meccanismi patogenetici alla base di questa citopenia si ritiene che possano riguardare la deregolazione citochinica, il danno alle HPCs, alle cellule in differenziamento e alle cellule stromali. Le cellule progenitrici ematopoietiche CD34+, dopo essere state separate da sangue cordonale e differenziate verso la linea eritroide, sono state trattate con HIV-1 attivo, inattivato al calore e gp120. In prima istanza è stata messa in luce la mancata suscettibilità all’infezione e l’aumento dell’ apoptosi dovuto al legame gp120-CD4/CXCR4 e mediato dal TGF-β1 nelle cellule progenitrici indifferenziate. L’aspetto innovativo di questo studio però si evidenzia esaminando l’effetto di gp120 durante il differenziamento verso la filiera eritrocitaria. Sono stati utilizzati due protocolli sperimentali: nel primo le cellule sono inizialmente trattate per 24 ore con gp120 (o con HIV-1 inattivato al calore) e poi indotte in differenziamento, nel secondo vengono prima differenziate e poi trattate con gp120. Il “priming” negativo determina una apoptosi gp120-indotta molto marcata già dopo 48 ore dal trattamento ed una riduzione del differenziamento. Se tali cellule vengono invece prima differenziate per 24 ore e poi trattate con gp120, nei primi 5 giorni dal trattamento, è presente un aumento di proliferazione e differenziamento, a cui segue un brusco arresto che culmina con una apoptosi molto marcata (anch’essa dipendente dal legame gp120-CD4 e CXCR4 e TGF-β1 dipendente) e con una drastica riduzione del differenziamento. L’insieme dei risultati ha permesso di definire in modo consistente la complessità della genesi dell’anemia in questi pazienti e di poter suggerire nuovi target terapeutici in questi soggetti, già sottoposti a cART.
Beside the CD4 T cells progressive loss, HIV-infected subjects exhibit some peripheral cytopenias. In particular, anemia is found in 10% of asymptomatic and in 92% of AIDS patients and cART therapy is not able to solve this problem. The pathogenic mechanisms underlying this cytopenia are related to cytokine dysregulation, damage of HPCs, impairment of stromal cells and inhibition of the differentiation of HPCs. The CD34+ hematopoietic progenitor cells were separated from cord blood, differentiated towards the erythroid lineage and treated with active HIV-1, heat-inactivated virus and gp120. First of all we demonstrate that HPCs are not susceptible to infection and the gp120-CD4/CXCR4 binding cause a TGF-β1 mediated apoptosis. The innovative aspect of this study, however, is evident examining the effect of gp120 during differentiation towards the erythrocyte. Two experimental protocols are used: in the first cells are initially treated for 24 hours with gp120 ( HIV-1 or with heat-inactivated ) and then induced into differentiation, in the second cells are firstly differentiated and then treated with gp120. The negative "priming" induces a gp120-mediated apoptosis 48 hours after treatment and a differentiation reduction. If these cells are instead primarily differentiated for 24 hours and then treated with gp120, in the first 5 days after treatment, there is an increase of proliferation and differentiation, which is followed by a very marked apoptosis (also TGF-β1 mediated and due to gp120-CD4/CXCR4 binding) and a drastic reduction of differentiation. These results allowed us to define the complexity of the genesis of anemia in these patients and suggest new therapeutic targets for these subjects already receiving cART .

Purpose: Age-related macular degeneration (AMD) is a devastating eye disease causing irreversible vision loss in the elderly. Retinal pigment epithelium (RPE), an important cell type afflicted in AMD, undergoes cell death in the late stages of the disease. Salient factors underlying AMD pathogenesis are aging, drusen components and NLRP3 inflammasome activity. The purpose of this dissertation is to elucidate the molecular interactions among these factors and how they contribute to RPE damage. Methods: The effects of aging on drusen components, in particular the membrane attack complex (MAC) and amyloid beta (Aβ) were examined in rats at different age. To determine the role of MAC in inflammasome activation in RPE, aurin tricarboxylic acid complex (ATAC), was administrated to naïve rats. To understand Aβ’s role in inflammasome activation, Aβ intravitreal injections were made into rat eyes in vivo and Vinpocetine was used to ameliorate the inflammatory responses. An in vitro RPE cell culture model was established to further investigate the relationship between inflammasome and X-chromosome linked inhibitor of apoptosis (XIAP). Statistical significance was set at p ≤ 0.05. Results: An age-dependent increase in MAC, Aβ, and NF-κB activation was observed in the RPE-choroid in vivo. Blocking MAC formation with ATAC led to a prominent reduction in inflammasome activity (caspase-1 cleavage and cytokine secretion), but not in NF-κB activity. Aβ intravitreal injections triggered inflammasome activation evidenced by enhanced caspase-1 cleavage and IL-1β/IL-18 release, which was suppressed by Vinpocetine mediated NF-κB inhibition. The robust inflammasome activity further led to gasdermin D-mediated activation of the pyroptotic pathway and a significant reduction in XIAP, which in turn enhanced IL-18 secretion. Conclusion: Aging is a strong risk factor for AMD, which increases the deposition of MAC and Aβ in the outer retina. The elevated levels of MAC and Aβ are triggers for inflammasome activation. By demonstrating a causal relationship between inflammasome activation and XIAP reduction, this dissertation suggests the precise regulation of XIAP, together with the suppression of MAC and NF-κB, may be crucial for controlling inflammasome activity and hence provides new avenues to prevent AMD.
Medicine, Faculty of
Graduate

Information is increasingly available at the touch of a button, and yet limits are still present in the ability and willingness of individuals to access that information. These limits can result in information avoidance, a phenomenon in which individuals prefer not to seek or be exposed to information. Nowhere is this phenomenon more evident and more problematic than in health, where information has been linked to better health outcomes, and where the consumer health movement has shifted the responsibility of health information seeking from healthcare professionals to patients. This dissertation examines such health information avoidance, looking in particular at the mechanisms that constitute this phenomenon, and the affective, personality, and information source factors that influence it. Two studies were performed, the first an online survey using the crowdsourcing platform Mechanical Turk for recruitment, and the second a user study in which participants interacted with health information and were then interviewed. Both studies also employed scales such as the Need for Cognition scale, the Threatening Medical Situations Inventory (examining monitoring and blunting styles), and the Positive and Negative Affect short scale. Results indicate that very few people are willing to report practising complete information avoidance. However, numerous participants reported avoiding some information, often through filtering mechanisms such as self-regulation and delegation. This evidence of partial avoidance suggests that information avoidance can be located on a continuum of information seeking behaviours, rather than existing as a simple negation of information seeking. Significant factors that influence the practice of information avoidance were found to include affect such as fear, disgust, and disinterest, all factors that can indicate a threat to the participant. While the personality and information source factors tested were also influential, this work found that for these participants, affective factors often functioned as a primary influence. This work indicates that health information avoidance is a situation-dependent information behaviour, rather than primarily a personality trait as previously claimed. As such, it should be included in models that depict people’s general behavioural patterns with regard to information, such as Wilson’s (1999) General Model of Information Seeking and Johnson’s (1997) Comprehensive Model of Information Seeking.
Arts, Faculty of
Library, Archival and Information Studies (SLAIS), School of
Graduate

This thesis focuses on an investigation of differential functioning in all options of multiple-choice items, referred to as differential options functioning (DOF). That is, DOF investigates whether respondents from different groups (i.e., subpopulations), with equal levels of attribute being measured, would have different probabilities to select the options. In previous research, DOF has been typically conducted as a secondary analysis for DIF of items in achievement/aptitude tests. This thesis introduces how DOF can provide fruitful information in various psychological and educational measurement contexts. In addition, this thesis proposes a set of integrated and straightforward procedures for investigating DOF based on the known theories of multinomial logistic regression. A demonstration is provided to guide the application of the proposed method.
Education, Faculty of
Educational and Counselling Psychology, and Special Education (ECPS), Department of
Graduate

Surface states of close-packed noble metals form an approximate two-dimensional electron gas whose many-body signatures can be locally probed using a scanning tunneling microscope (STM). In this work I present a study of the Cu(111) surface state with high-resolution Fourier Transform Scanning Tunneling Spectroscopy (FT-STS), and for the first time demonstrate that the energy dispersion and quasi-particle lifetime of the surface states can be accurately quantified in both the occupied and unoccupied states. The scat-tering phase-shift imposed by defect potentials is then extracted in Fourier space, which is consistent with previous real space analyses. This result is later used in the T-matrix simulation of the density of states that gives an accurate description of our data. Finally, I report that in dilute Co/Cu(111) where the absence of time-reversal symmetry allows for spin-flip scattering, spin-conserving scattering dominates the FT-STS signal.
Science, Faculty of
Physics and Astronomy, Department of
Graduate

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 58-60).
The numerical approximation of the Poisson equation can often be found as a subproblem to many more complex computations. In the case of Lagrangian approaches of flow equations, the Poisson equation often needs to be solved on an irregular point distribution. Currently, mainly unstructured mesh-based approaches are used. Meshfree methods present a way to approximate differential operators on unstructured point clouds without the need for mesh generation. In this thesis, a 3d meshfree finite difference Poisson solver is presented. Its performance has been studies based on numerical convergence, parallel efficiency, and computational cost. Practical application of the solver is presented in a simulation of a potential flow field in a wall-bounded domain.
by Anna Vasilyeva.
S.M.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Biology, 2011.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references.
The general amino acid permease Gap1p of Saccharomyces cerevisiae scavenges amino acids from the extracellular medium for use as nitrogen sources in starvation conditions. Because unlimited uptake of both naturally occurring amino acids and amino acid analogs is toxic, Gap1p is active at the plasma membrane only when amino acid levels are low. Gap1p is down regulated when amino acids are abundant by two distinct post-translational mechanisms. Gap1p is regulated post-translationally to respond quickly and efficiently to changing amino acid concentration. An increase in amino acids causes accumulation of Gap1p in the vacuole and inactivation of Gap1p located at the plasma membrane. Conversely, a decrease in amino acid levels allows for redistribution of Gap1p from internal membranes to the cell surface. Here I examine the mechanism of amino acid regulation of Gap1p. Previous studies of Gap1p sorting have focused on the trans-acting factors required for the distribution of Gap1p between the plasma membrane and internal compartments. To complement this body of work, these studies focus on the cis-elements required for Gap1p sorting. We find that post-translational regulation of Gap1p requires the catalytic activity of Gap1p, indicating that sorting and activity of Gap1p are controlled in cis. Gap1p therefore can serve as an amino acid sensor to control its activity in response to nutrient levels. This finding suggested that post-translational regulation of Gap1p could apply to other transporter proteins in yeast. I examined the activity and localization of a related transporter protein, the histidine-specific permease Hip1p in response to various amino acids, and found that although Hip1p is down regulated only in response to histidine, this regulation is less tightly controlled than the regulation of Gap1p. This observation supports previous assertions that the function of Gap1p in the cell is distinct among yeast amino acid transporters.
by Natalie E. Cain.
Ph.D.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Linguistics and Philosophy, 2010.
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (p. 155-159).
This dissertation develops a grammar of phonetic implementation of phonologically significant F0 (pitch) events, which is applicable across languages. Through production studies of various languages, we show that phonetic universals exist which govern phonetic realization of the phonological representations of tones. In the previous literature, there have been two conflicting views concerning tonal timing: tones are aligned with respect to segments (the Segmental Anchoring Hypothesis) or tones occur at a fixed interval from other tones (the Constant Duration Hypothesis). In this dissertation, the two hypotheses are tested in languages with various tonal phonologies: Seoul Korean (phrasal boundary tone), Tokyo Japanese (lexical pitch accent), Mandarin (lexical tone), and English (intonational pitch accent). In all languages, both tendencies to maintain segmental alignment and a target duration for pitch rises are simultaneously observed. We thus adopt a weighted-constraint model (Flemming, 2001) where segmental alignment and target duration are interpreted as weighted constraints. In this model, timing of tones is determined to minimize the summed cost of violation of these conflicting constraints. Mixed-effects models were fitted to the data to obtain the actual weights in each language. Relative weights of the constraints reflect cross-linguistic differences in the alignment of tones. The relative weights of constraints in the phonetic realization grammar are not random but systematic, reflecting the phonological nature of tones in each language. The experimental studies in this dissertation show that tonal alignment patterns depend on phonological status and context of tones. Lexically-contrastive tones (Japanese accented words, Mandarin lexical tone) or prominence-lending tones (English pitch accents) are more strictly aligned with respect to their anchoring points than phrasal boundary tones (Seoul Korean, Japanese unaccented words), if other conditions are equal. Tones show different alignment patterns depending on phonological context: tones are more strictly aligned in word-final context than in word-medial context in Japanese accented words, and in lexical-tone context than in neutral-tone context in Mandarin. In addition, languages show different phonetic realization patterns depending on whether contour tones are contrastive in the language (Mandarin and English) or not (Korean and Japanese). These results point to the fact that details of phonetic realization of tones are determined by language-specific phonetic realization grammar, rather than by default universal rules.
by Hyesun Cho.
Ph.D.

Thesis (M.C.P.)--Massachusetts Institute of Technology, Dept. of Urban Studies and Planning, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 35).
This study evaluates the performance of low income housing subsidy programs currently operating in Chile. The use of detailed microdata allows a close assessment of the relationship between individual subsidy grants, characteristics of the units purchased and actual transaction prices. The study entails both the comparison between programs with different incentive frameworks, and the relative performance of each of these programs in a context of major increases in the levels of assistance provided. The evidence suggests that in most cases virtually the entire increase in the subsidy to the purchaser, which is intended to make housing more affordable, is translated into increased housing prices. In fact, in subsidized transactions between 2007 and 2009 the agreed purchase prices were almost entirely determined by the maximum subsidy amounts set by the housing authority. This occurred repeatedly in transactions performed through programs where the granted subsidy was virtually a 1 to 1 function of the agreed transaction price and where subsidy beneficiaries have little or no incentive to bargain. In such a framework, all the increases in subsidy levels that occurred in the period were translated into equivalent increases in prices with very limited improvements in the quality and location of the units purchased. On the contrary, prices tended to move much more closely with the unit's predicted price (determined by its actual characteristics) in less generous programs that provide lump sum transfers and where beneficiaries are responsible for paying larger proportions of the balance. However, even in these cases, up to 64 cents per dollar of housing subsidy are estimated to be translated directly into house price inflation. The estimated positive impact of subsidy amounts on prices of existing units is a form of wealth transfer that benefits current owners. Although the majority of today's sellers in this segment are low to middle income households that benefited from housing policy efforts in previous decades, these owners are certainly wealthier than current subsidy beneficiaries and also wealthier than other households still waiting to receive housing assistance. Such wealth transfers may be inappropriate, and undermine the declared goal of targeting housing assistance efforts on those who need it most.
by Slaven Antonio Razmilic Burgos.
M.C.P.

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 75).
The incorrect slitting is the defect waste in slitting process which does not meet the single pack width and crease-to-edge width requirements. It is the highest contributor to the overall defect waste in slitting process at Company X Jurong (CXJ). To address this problem, the key input and output variables were identified. The inputs are the tension settings and knives' positioning, and the output is crease-to-edge width. The objectives are to optimize the tension settings and to achieve a centered process by a proper calibration of knives' positioning. The Design of Experiments (DoE) was conducted to study the significance of tension towards crease-to-edge width variance. For 200 mL pack size, it was found that the variance is constant within the allowable setting range. For 250 mL pack size, it was found that the overall average variance best represents the variance of the data within the allowable range. However, the process is currently off-centered. Therefore, a proper training for detecting any mean shift happening in the process to the operators utilizing the digital camera measurement system is recommended.
by Willy Perdana Tanuwijaya.
M.Eng.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Architecture, 1991.
Includes bibliographical references (leaves 85-89).
Most of the information in this proposal is derived from my former and current research on Beirut, Methodology for Slow Conservation of War-Damaged Structures in Downtown Beirut. In the earlier version I have failed to highlight the significance of the Martyrs Square area. My aim in this addendum is to shed more light on the above. By doing so the conservation/rehabilitation zone takes on more of an inclusive and representational character, reflective of the richness and variety inherent in Beirut's complex urban fabric. An intriguing aspect of this study is the rather remote chance for implementing any such reconstructive schemes. Given the recent rounds of fighting, it has become more hopeless to conceive of any notion of conservation or rehabilitation. A positive aspect, however, may be derived from the existing schemes already drafted during this decade, for the area's possible rehabilitation/conservation. The recent decree for the opeirlng of "Greater Beirut" by President Elias Hrawi sheds more optimism. It is with the hope that some day soon the Lebanese conscience and that of the world will prevail so that humanity and people may live, enjoy, produce, thrive and flourish more abundantly - that history proves, as it has done in the past, that destruction can be overcome. Only then, we could possibly talk about more than surveys and protective measures to safeguard our historic heritage. This will be the time to restore and rehabilitate the New Martyrs Square in memory of those who died in the late Civil War. The second part of the thesis expands the scope of the subject to include the Shouf region. It is here that the roots for regional Lebanese architecture are inherent. While fighting and bombing have also shattered a considerable number of significant structures in this area; the process of reconstruction and occasional restoration has proven more effective than in urban Beirut. The process was carried over on the initiative of individuals. The primary reasons for such immediate intervention on the part of individuals was the advantage of less constraints in terms of the absence of bureaucracies (even with dramatically less fundamental support) and needless to say the lack of written conservation more comprehensive strategy for the area. Instead, alternate examples of almost identical character and plan will be substituted. legislation; these ,together boosted the rehabilitation/restoration process. A great many historical edifices and even more modest structures have already been fully restored, while the bulk of Beirut's historical structures and quarters are decaying with time and neglect. An equally important aspect in this scenario is the nature of the occupants and their attitudes toward preservation. While mountain dwellers seem more attached to their land and homestead, and accordingly are very reluctant to leave their surroundings, the city dwellers are more prone to mobility and social change. This aspect resulted in more restoration efforts in the mountains and accordingly less such in Beirut. Moreover, the building type most affected by destruction in Beirut happens to be concentrated in the heart of the city, Le.; the central business district, where hardly any residential apartment buildings exist. People seem to be more attached to their primary and more immediate surroundings, such as their own houses, which makes them more inclined by force-majeur to restore their dwellings. The last part of this thesis attempts to propose some particular "bylaws" or "clauses" regarding appropriate intervention. Consideration will be given to adaptive - reuse issues; especially as to what extent significant structures can be adaptively reused according to local conventions. No written bylaws exist in this sphere and the only precedent seems to encompass civil and religious buildings; this renders such an issue extremely delicate, if not controversial. This also leads us to one other major question -- to what extent should legislation permit physical alteration of historical structures? Finally, an integral element in this thesis is the lack of conservation legislation in third world countries in general of which Lebanon is only one example; and how could legislation and local conventions be more effective through implementation in wider parts of the Middle East region, especially after the war. ·On the whole, this thesis attempts to raise questions, suggest certain possible solutions to given problems, provide a status quo report from 1982 to the present, and family draw conclusions. The conclusions are by no means rigid and therefore remain subject to debate and further questioning.
by Naji Maher-Nasr-e-din Al-Hasani.
M.S.

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Linguistics and Philosophy, 2010.
Cataloged from PDF version of thesis.
Includes bibliographical references (p. 81-84).
In this thesis, I try to answer some basic questions about the a priori. Namely, what is it supposed to be? Should we believe in its existence? And is it important? Chapter One, "The Problem of Forgotten Evidence," sets the stage. I introduce the distinction between internalism and externalism, which plays a crucial role throughout the thesis. Roughly speaking, internalists think that one is justified in holding a given belief only if one can access adequate evidence for it, upon reflection, while externalists deny this. I argue that only an externalist can explain why we are now justified in believing things, such as facts about world history, which we originally learned on the basis of reasons we have since forgotten. Chapter Two, "Two Notions of A Priori Justified Belief," distinguishes between two ways of understanding what a priori justified beliefs are supposed to be, an internalist way and an externalist way. I argue that the two ways of understanding what a priori justified beliefs are lead to different and somewhat surprising outcomes regarding how much is a priori. When thought of in the internalist way, a priori justified beliefs are unstable and especially hard to come by in the first place. When thought of in the externalist way, however, they are secure and easier to acquire. Chapter Three, "The Importance of the A Priori," argues that there is no reason to think that the a priori is important in the strong sense which some philosophers seem to think it is. They argue for their view on the grounds that our ability to learn about the world depends on our being a priori warranted in relying on certain belief forming procedures, like taking our perceptual experiences at face value, and accepting the testimony of other people. I show that there is a sense in which that is true, but that, in that sense, it does not support the strong conclusion they ultimately want. One would mistakenly think that it does only if one illicitly switched back and forth between internalist and externalist perspectives.
by Ari L. Krupnick.
Ph.D.

La Inteligencia Emocional tiene antecedentes en la evolución histórica de las investigaciones sobre la inteligencia, desde sus orígenes a principios del siglo veinte hasta las inteligencias múltiples ochenta años después. La inteligencia emocional es un constructo que surge con Salovey y Mayer en 1990 y se difunde con Goleman en el año 1995. De esta misma forma, para las habilidades emocionales, las relaciones interpersonales son las que se basan en el autocontrol y la empatía, ponerse en el lugar del otro, e implican el desarrollo de la competencia social, la cooperación y los lazos de amistad (Goleman, 1996). La inteligencia emocional es una base fundamental de las competencias emocionales, aunque de igual manera la inteligencia emocional se encuentra sumamente ligada a las habilidades emocionales ya que, el aprender a quererse, a conocerse, a relacionarse y a desenvolverse, son comunes en la vida cotidiana del ser humano, ya que se adquieren a base de la práctica. Debido a esto es vital que desde una temprana edad los niños aprendan que existen distintos tipos de situaciones y que cada una les exigirá una u otras respuestas, para aprender a tomar las decisiones más convenientes y resuelvan de la mejor manera problemas cotidianos.
Para la realización de este trabajo de investigación se utilizó un estudio de tipo descriptivo, cuyo objetivo fue desarrollar la propuesta de un programa de habilidades emocionales para niños de educación primaria con base a una medición, en una población conformada por 162 alumnos de los cuales 88 fueron del sexo femenino (correspondiente al 54%) y 74 del sexo masculino (correspondiente al 46%), agrupados en cinco grupos (A, B, C, D, E). Se empleó el instrumento de Habilidades emocionales elaborado por Solórzano (2009), este instrumento explora las habilidades emocionales en niños de 6 a 12 años. El cual está conformado por cinco factores siendo estos: amistoso, control del genio, cariñosos, persistencia, reconocimiento. Los resultados obtenidos fueron que ambos géneros muestran una media alta en el factor amistoso y una media baja en el factor de persistencia.
Universidad Autónoma del Estado de México

Condições naturais, de ordem paisagística, dotaram os Açores de elementos que privilegiam o turismo. O desenvolvimento do fenómeno turístico requer a criação de estruturas e actividades económicas de apoio, nomeadamente ao nível do alojamento. A importância da actividade turística nos Açores conduziu à escolha deste sector e um dos seus elmentos principais, o conjunto dos meios de alojamento, para aplicação da análise estratégica e da metodologia dos grupos estratégicos. O objectivo do estudo é o da identificação de grupos estratégicos na indústria de hotelaria dos Açores, com base nas estratégias genéricas de Porter, e relaciona-los com o desempenho das unidades hoteleiras. O estudo foi realizado com base num inquérito efectuado à Direcção das unidades hoteleiras para identificação das estratégias seguidas.

[EN] Today, it is well stablished that there is a need to reduce energetic consumption among different human activities and also in buildings; the rhythm of today's waste is no longer acceptable for the planet in terms of sustainability. The degree of comfort to which we have get used to, and to which society does not seem to renounce, places in the focus of the problem. Comfort is a very wide concept that includes the perception of multiple ambient parameters, but in relation to the problems exposed, we will focus on higrothermal and daylight approaches. In that sense, architects cannot ignore this reality, so it is appropriate to deal with it since the very beginning of the architectural project from a holistic point of view. Mostly, when recent researches demonstrate that the decisions taken in the early design phases have influence over the 80% of the building's energy performance. Spanning from the Renaissance to nowadays, along three centuries, the modern era comprises a period with huge human development. Even though, it has two common parameters in cultural terms; it has been -and still is¿a culture of projects and it is also steeped in the hegemony of visual. The prevailing oculocentrism makes that image and objects as a consumer product, perceived through the eye, have focused design parameters. Architecture, whether as a result or a contextual engine, has not been foreign to these two realities. Only departing from the avant-garde movements of the past century, it is possible to find examples of intentional sensibility towards the environment and other less material issues, for instance comfort, especially in the second generation of the fifties and the sixties. With the growing use of "fenomenology" and "hapticity" when describing inhabited environments, new variables come into play. Architects, acting as planners conceiving the places where people live, have not been able to introduce these matters in everyday tasks. All that we perceive through our sensory channels is much more than just what we see, so it seems, that in some way, it needs to take its place in the design processes. In addition, as stated by Ortega y Gasset, the higher degree of technification of the milieu appears to have led us to a thoughtless and empty adaptation of the system of instrumental rationality. The trust in technology as the only way to solve human problems is an argument that is losing strength with the passing of the 21st century. Peter Collins believed that the study of how people built in the past is completely different to the study of how they do it today yet indivisible. Based on this approach and taking into account all said before, Le Corbusier's architectural project is studied from the higrothermal and sensory perspective, as well as the Grille Climatique, tool developed in his atelier at the early fifties to control these areas. The techniques available at our time -analysis, simulation, monitoring and user perception - are used to demonstrate the system adequacy and possible future applications. Conclusions will be drawn through contrast with other tools developed later and comparison between Pavillon Suisse and Maison du Brésil, designed before and after the Grille Climatique, searching to what extent Le Corbusier took into account certain intangible variables in the design process.
[ES] Nos encontramos en una época en la que es patente la necesidad de una reducción del consumo energético en varias actividades humanas y también en la edificación, el ritmo de gasto actual no es admisible para el planeta en términos de sostenibilidad. El grado de comodidad al que nos hemos acostumbrado, y que como sociedad no parece que estemos dispuestos a renunciar, se sitúa en el centro de la problemática. Aunque el confort es un concepto muy amplio que incluye la percepción de múltiples parámetros ambientales, en relación a la temática expuesta, se centra en el higrotérmico y lumínico. Así, los arquitectos no podemos desentendernos de esta realidad y por tanto, es conveniente abordarla a partir del proyecto arquitectónico desde un punto de vista holístico. Y más, cuando estudios recientes demuestran que las decisiones tomadas en las primeras fases del diseño influyen sobre el 80% del comportamiento energético del edificio. La era moderna, que nace con el Renacimiento y que llega hasta nuestros días, con toda la evolución histórica acaecida en este lapso de más de tres siglos puede, aun así, caracterizarse por dos parámetros comunes. En términos culturales, ha sido desde el comienzo ¿todavía lo es en nuestros días¿una cultura de proyecto y además se encuentra sumida en una total hegemonía de lo visual. El oculocentrismo reinante hace que la imagen y el objeto como producto material, que se percibe a través de la vista, hayan centrado los parámetros de diseño. La arquitectura, ya sea como resultado o motor contextual, no ha sido ajena a estas dos realidades. Solo a partir de los movimientos de vanguardia del siglo pasado empezaron a mostrarse ejemplos de declarada sensibilidad hacia el medio y otras cuestiones menos materiales, dígase el confort, especialmente en la segunda generación de los años cincuenta y sesenta. Con la aparición de la fenomenología y la hapticidad, como términos habituales en la descripción de los entornos habitados, se ponen en juego nuevas variables que se mueven en ámbitos que todavía, los arquitectos, como proyectistas, como pensadores del entorno que las personas van a vivir, no hemos acabado de asumir como colectivo. Todo aquello que percibimos a través de los canales sensoriales, es mucho más que lo que vemos y por tanto parece necesario que de algún modo pueda ocupar su lugar correspondiente en el proceso de diseño. Adicionalmente, una creciente tecnificación del entorno parece, tal y como indicaba Ortega y Gasset, que nos ha llevado a una adaptación irreflexiva y vacía del sistema de la racionalidad instrumental. La confianza en que la tecnología, per se, puede solucionar todos los problemas a los que se enfrenta el ser humano es una reflexión que va perdiendo fuerza con el devenir del siglo XXI. Peter Collins creía que el estudio de la manera en la cual la gente había construido en el pasado y el estudio en que la gente construye en el presente, son dos cosas totalmente distintas y sin embargo, inseparables. Partiendo de este planteamiento y teniendo en cuenta todo lo expuesto anteriormente, se aborda el estudio del proyecto arquitectónico de Le Corbusier, en términos higrotérmicos y sensoriales, y de la Grille Climatique, herramienta desarrollada en su atelier a principios de los cincuenta, para controlarlos. Con los medios y técnicas actuales ¿análisis, modelizado, monitorización y percepción del usuario¿comprobamos la adecuación de este sistema y sus posibilidades de aplicación. A través de la relación con otras herramientas desarrolladas posteriormente y de la comparación entre el Pavillon Suisse y la Maison du Brésil, ideados antes y después, respectivamente, de la Grille Climatique, buscamos entender hasta qué punto, Le Corbusier tuvo en cuenta ciertas variables intangibles para su inclusión proyectual y de ello extraer conclusiones.
[CA] Ens trobem en una època en la que es fa patent la necessitat d'una reducció del consum energètic en diverses activitats humanes i també en la edificació, el ritme de despesa actual no es admissible per al planeta des de la perspectiva de la sostenibilitat. El grau de comoditat al que ens hem acostumat, i que com a societat no sembla que estem disposats a renunciar, es col.loca en el centre de la problemàtica. Encara que el confort es un concepte molt ample que inclou la percepció de múltiples paràmetres ambientals, en relació amb la temàtica exposada, es centra en el higrotèrmic i lumínic. Així, els arquitectes no podem desentendre'ns d'aquesta realitat i per tant, es convenient abordar-la des del projecte arquitectònic des d'un punt de vista holístic. A més, quan els estudis recents demostren que les decisions presses en les primeres fases del disseny influeixen fins al 80% del comportament energètic de l'edifici. La era moderna, que naix amb el Renaixement i que arriba fins als nostres dies, amb tota l'evolució històrica esdevinguda en eixe lapse de més de tres segles pot, tot i així, caracteritzar-se per dos paràmetres comuns. En termes culturals, ha sigut des del començament -encara ho es hui en dia¿una cultura de projecte i a més a més es troba sotmesa en una total hegemonia de lo visual. El oculocentrisme regnant fa que la imatge i l'objecte com a producte material, que es percebut a través de la vista, hagen centrat els paràmetres de disseny. L'arquitectura, bé com a resultat o com a motor contextual, no ha sigut aliena a estes realitats. Tan sols des dels moviments d'avantguarda del segle passat començaren a mostrar-se exemples de declarada sensibilitat cap al medi i altres qüestions menys materials, com el confort, especialment en la segona generació dels anys cinquanta i seixanta. Amb l'aparició de la fenomenologia i la hapticitat, com a termes habituals en la descripció dels entorns habitats, entren en joc noves variables que es mouen en àmbits que encara, els arquitectes, com a projectistes, com a pensadors de l'entorn que les persones van a viure, no hem acabat d'assumir com a col.lectiu. Tot aquell que percebem a través dels canals sensorials, es molt més que allò que veiem y en conseqüència pareix necessari que d'alguna forma ocupi el seu lloc corresponent en el procés de disseny. Addicionalment, una creixent tecnificació de l'entorn pareix, tal i com indicava Ortega y Gasset, que ens ha portat a una adaptació irreflexiva i buida del sistema de la racionalitat instrumental. La confiança en que la tecnologia, per se, pot solucionar tots el problemes als que fa front l'ésser humà és una reflexió que va perdent força amb l'esdevenir del segle XXI. Peter Collins creia que l'estudi de com la gent havia construït en el passat i l'estudi de com la gent construeix en el present, són dos coses totalment diferents i no obstant això, inseparables. Partint d'aquest plantejament i tenint en compte tot allò que s'ha exposat abans, s'aborda l'estudi del projecte arquitectònic de Le Corbusier, en termes higrotérmics i sensorials, i de la Grille Climatique, eina desenvolupada en el seu atelier al començament dels cinquanta, per a controlar-los. Amb els mitjans i tècniques actuals -anàlisi, modelat, monitorització i percepció de l'usuari-comprovem l'adequació d'aquest sistema i les seves possibilitats d'aplicació. A través de la relació amb altres eines desenvolupades posteriorment i de la comparació entre el Pavillon Suisse i la Maison du Brésil, ideats abans i després, respectivament, de la Grille Climatique, busquem entendre fins a quin punt, Le Corbusier va tenir en compte certes variables intangibles per a la seva inclusió projectual i d'això extreure conclusions.
Martín Fuentes, DV. (2016). LE CORBUSIER Y LA GRILLE CLIMATIQUE. Herramientas para la inclusión de variables termodinámicas y sensoriales en el proyecto arquitectónico [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62412
TESIS

The purpose of this study was to investigate factors affecting the use and non-use of free and low-cost library electronic information resources by information specialists (librarians charged with e-resource responsibilities), academic staff and postgraduate students in scientific, technological and medical (STM) disciplines at universities in Zimbabwe. The research problem was: What are the factors affecting the use and non-use of e-resources by information specialists, academic staff and postgraduate students in scientific, technological and medical (STM) disciplines at universities in Zimbabwe? To address this problem, several sub-questions were set, covering the situation of free and low-cost e-resources available to Zimbabwean universities, factors influencing access to e-resources, the actual use of such resources, and how these problems should be addressed. The study also considered reports from related studies. Using convenience and purposive sampling depending on the participant group, empirical data were collected from information specialists, academic staff and post-graduate students from five universities in Zimbabwe (Africa University, Chinhoyi University of Technology, Midlands State University, National University of Science and Technology and University of Zimbabwe) from May to July 2015. Quantitative and limited qualitative data were collected through questionnaires administered to library directors, information specialists, academic staff and post-graduate students in the STM disciplines. Four library directors or their representatives, 38 information specialists, 80 academic staff, 121 master’s and 14 doctoral students were involved in the study. Descriptive statistical data on all four groups and inferential statistical data on information specialists, academic staff and postgraduate students are provided. Content analysis was applied to qualitative data to reveal views on factors affecting the use of e-resources. The universities provide access to scholarly literature through large collections of e-resources by means of various databases, e-books and electronic theses and dissertations. The availability of journals is no longer a principal problem; the challenge is how to ensure that what is available can be accessed and is used to best effect. Access to computers is also not a problem, especially for information specialists. There are, however, problems with internet infrastructure (i.e. slow and/or unreliable internet, shortage of internet bandwidth), limited user skills and limited user awareness of available library e-resources. Inferential statistical data analysis determined that the position of the information specialist, whether junior or senior, has an important impact on their use of e-resources. Juniors tended to use e-resources more often than seniors. Good technical support when encountering problems with e-resources had the most significant influence on downloading of full-text articles by information specialists. The general linear model test identified lack of skills in using the e-resources as the factor with the highest significance, compared to other variables that had an effect on the use of e-resources by academic staff in STM disciplines. Of the seven significant variables that affected the frequency with which academic staff downloaded full-text articles, the factor of academic staff duties involving research and supervision of students had the highest significance value. On testing factors influencing postgraduate students’ frequency of using e-resources and their frequency of downloading full-text articles, postgraduate students’ training on Google Scholar was established to have the highest significance regarding both. Recommendations include: improved investment in user skills training and information literacy; tools to improve the discoverability of e-resources and content provided by libraries; effective marketing strategies to improve the use and uptake of e-resources by academic staff and students; ensuring that content covered by e-resources is relevant and up to date; providing technical support to e-resource users when they encounter problems; and ensuring adequate IT and internet infrastructure.
Thesis (PhD)--University of Pretoria, 2017.
Information Science
PhD
Unrestricted

This study compared the projections by young people in a rural school of risk factors and protective resources in the first and second sand tray. From an indigenisation perspective, the assumption was that sand tray therapy could be suitable to understand risk factors and protective resources in two sand trays of young people. As part of a clinical case study design first and second sand trays (n=22) of clients (n=11) were purposefully selected for comparative analysis. Data sources included visual data (photographs), accompanying client narratives (verbatim transcriptions and field notes), ASL student reflections, and semi-structured interviews with purposefully sampled ASL students. Following thematic data analysis two main themes emerged: risk and protection in first and second sand trays of young people in a rural school; and progression in projections of first and second sand trays of young people in a rural school. Sand tray therapy has utility for use with young people in a rural ecology to (i) use as a contextually and culturally appropriate technique (ii) use in groups in school-based educational psychology services (iii) assess risk factors, (iv) protective resources and (v) the use of first and second sand trays for young people to project positive progression in their experiences of their life-worlds. Consequently, educational psychologists can integrate sand tray therapy, as a contextually appropriate technique, into intervention programmes to understand the experiences of young people in rural ecologies and support them.
Dissertation (MEd)--University of Pretoria, 2017.
Educational Psychology
MEd
Unrestricted

[EN] SUMMARY The insecurity among the population, is the most important concern for the inhabitants of Latin America, Argentina , and also Rio Negro State. Its complex causes make do an investigation about the historical facts of the territory, the evolution of the theory and statistics in order to understand the condition and development of the events. During the period 1995-2012, the province of Río Negro had an economic growth and reduced its inequality levels; it improved the unemployment conditions and the education rate. However, the crime rates did not diminish, thus, the population`s feeling of insecurity could not be reduced. Concomitantly, those variables that discourage crime (for the utilitarian approach) have gone down al through the period, and this descent is much higher for the last year. Undoubtedly, a right use of the contributions in this paper, brings about new questions that will have to look for answers in subsequent research.
[ES] Resumen La inseguridad ciudadana constituye la principal preocupación de los habitantes de América Latina, de Argentina y también de la provincia de Río Negro. Sus complejas causas obligan a realizar una investigación sobre los hechos históricos del territorio, la evolución de la teoría y las estadísticas, con el fin de interpretar el estado y desarrollo de los acontecimientos. En el periodo de estudio 1995-2012 la provincia de Río Negro creció en su economía y redujo sus niveles de desigualdad, mejoró el desempleo y la tasa de escolaridad. Sin embargo, no mejoraron las tasas de delincuencia y con ello, no logró reducir la sensación de inseguridad en la población. Concomitantemente las variables que desalientan la delincuencia (para el enfoque utilitarista) han descendido en todo el período y este descenso es mucho mayor para el último año. No cabe duda de que la utilización adecuada de los aportes al conocimiento que se revelan en el presente trabajo, genera nuevas preguntas que deberán buscar respuestas en posteriores investigaciones.
[CAT] Resum La inseguretat ciutadana constitueix la principal preocupació dels habitants d'Amèrica Llatina, d'Argentina i també de la província de Riu Negre. Els seus complexes causes obliguen a realitzar una investigació sobre els fets històrics del territori, l'evolució de la teoria i les estadístiques, per tal d'interpretar l'estat i desenvolupament dels esdeveniments. En el període d'estudi 1995-2012 la província de Riu Negre va créixer en la seua economia i va reduir els seus nivells de desigualtat, va millorar la desocupació i la taxa d'escolaritat. No obstant això, no van millorar les taxes de delinqüència i amb això, no va aconseguir reduir la sensació d'inseguretat a la població. Concomitantment les variables que desanimen la delinqüència (per l'enfocament utilitarista) han baixat en tot el període i aquest descens és molt més gran per a l'últim any. No hi ha dubte que la utilització adequada de les aportacions al coneixement que es revelen en el present treball, genera noves preguntes que hauran de buscar respostes en posteriors investigacions.
Abadovsky, MD. (2016). Seguridad Ciudadana y Desarrollo Económico Social en la Provincia de Río Negro, Patagonia Argentina [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/62212
TESIS

Les algorithmes d'apprentissage automatique sont reconnus pour leurs performances impressionnantes sur de nombreuses tâches que l'on croyait dédiées à l'esprit humain, de la reconnaissance des chiffres manuscrits (LeCun et al. 1990) au pronostic du cancer (Kourou et al. 2015). Néanmoins, l'apprentissage automatique devenant de plus en plus omniprésent dans notre quotidien, il existe un besoin croissant de comprendre précisément leurs comportements et leurs limites.La théorie de l'apprentissage statistique est la branche de l'apprentissage automatique qui vise à fournir un formalisme de modélisation solide pour les problèmes d'inférence ainsi qu'une meilleure compréhension des propriétés statistiques des algorithmes d'apprentissage.Il est important de noter que la théorie de l'apprentissage statistique permet (i) de mieux comprendre les cas dans lesquels un algorithme fonctionne bien (ii) de quantifier les compromis inhérents à l'apprentissage pour des choix algorithmiques mieux informés (iii) de fournir des informations pour développer de nouveaux algorithmes qui finira par surpasser ceux existants ou s'attaquer à de nouvelles tâches. S'appuyant sur le cadre d'apprentissage statistique, cette thèse présente des contributions liées à trois problèmes d'apprentissage différents : l'apprentissage en ligne, l'apprentissage des modèles génératifs et, enfin, l'apprentissage équitable.Dans la configuration d'apprentissage en ligne - dans laquelle la taille de l'échantillon n'est pas connue à l'avance - nous fournissons des bornes de déviations (ou intervalles de confiance) uniformes dans la taille de l'échantillon dont la largeur a le taux donné dans la loi du logarithme itéré pour une classe générale de M-estimateurs convexes -- comprenant la moyenne, la médiane, les quantiles, les M-estimateurs de Huber.En ce qui concerne les modèles génératifs, nous proposons un cadre pratique pour étudier les modèles génératifs adversariaux (Goodfellow et al. 2014) d'un point de vue statistique afin d'évaluer l'impact d'une (éventuelle) faible dimensionnalité intrinsèque des données sur l'erreur du modèle génératif. Dans notre cadre, nous établissons des limites de risque non asymptotiques pour le minimiseur du risque empirique (MRE).Enfin, notre travail sur l'apprentissage équitable consiste en une large étude de la contrainte de parité démographique (DP en anglais), une contrainte populaire dans la littérature sur l'apprentissage équitable. La parité démographique contraint essentiellement les prédicteurs à traiter les groupes définis par un attribut sensible (par exemple, le sexe ou l'origine ethnique) pour qu'ils soient « traités de la même manière ». En particulier, nous proposons un cadre statistique minimax pour quantifier précisément le coût en risque d'introduire cette contrainte dans le cadre de la régression
Machine learning algorithms are celebrated for their impressive performance on many tasksthat we thought were dedicated to human minds, from handwritten digits recognition (LeCunet al. 1990) to cancer prognosis (Kourou et al. 2015). Nevertheless, as machine learning becomes more and more ubiquitous in our daily lives, there is a growing need for precisely understanding their behaviours and their limits.Statistical learning theory is the branch of machine learning which aims at providing a powerful modelling formalism for inference problems as well as a better understanding of the statistical properties of learning algorithms.Importantly, statistical learning theory allows one to (i) get a better understanding of the cases in which an algorithm performs well (ii) quantify trade-offs inherent to learning for better-informed algorithmic choices (iii) provide insights to develop new algorithms which will eventually outperform existing ones or tackle new tasks. Relying on the statistical learning framework, this thesis presents contributions related to three different learning problems: online learning, learning generative models and, finally, fair learning.In the online learning setup -- in which the sample size is not known in advance -- we provide general anytime deviation bounds (or confidence intervals) whose width has the rate given in the Law of Iterated Logarithm for a general class of convex M-estimators -- comprising the mean, the median, quantiles, Huber’s M-estimators.Regarding generative models, we propose a convenient framework for studying adversarial generative models (Goodfellow et al. 2014) from a statistical perspective to assess the impact of (eventual) low intrinsic dimensionality of the data on the error of the generative model. In our framework, we establish non-asymptotic risk bounds for the Empirical Risk Minimizer (ERM).Finally, our work on fair learning consists in a broad study of the Demographic Parity (DP) constraint, a popular constraint in the fair learning literature. DP essentially constrains predictors to treat groups defined by a sensitive attribute (e.g., gender or ethnicity) to be “treated the same”. In particular, we propose a statistical minimax framework to precisely quantify the cost in risk of introducing this constraint in the regression setting

Liu (1996) discussed a class of robust normal/independent distributions which contains a group of thick-tailed cases. In this article, we develop a skewed version of these distributions in the multivariate setting, and we call them multivariate skew normal/independent distributions. We derive several useful properties for them. The main virtue of the members of this family is that they are easy to simulate and lend themselves to an EM-type algorithm for maximum likelihood estimation. For two multivariate models of practical interest, the EM-type algorithm has been discussed with emphasis on the skew-t, the skew-slash, and the contaminated skew-normal distributions. Results obtained from simulated and two real data sets are also reported.
Liu (1996) discute una clase de distribuciones robustas a las que apela como normal/independiente, y que contiene un grupo de distribuciones de colas pesadas. En este artículo desarrollamos una versión asimétrica de tales distribuciones en un escenario multivariado, a las que llamaremos distruciones normales asimétricas independientes multivariadas. Para tales distribuciones derivamos algunas propiedades. La principal virtud de los miembros de esta familia es que son fáciles de simular y se prestan a un algoritmo de tipo EM para realizar estimaciones de máxima verosimilitud de sus parámetros. Para dos modelos multivariados de interés práctico se discute el algoritmo EM con énfasis en las distribuciones t-asimétrica, slash asimétrica y normal asimétrica contaminada. Los resultados obtenidos a partir de simulaciones y de dos conjuntos de datos reales son reportados.

Actualmente existe un gran número de lesiones y enfermedades que afectan el tejido óseo. El origen de estos problemas es diverso y su tratamiento también es diferente en cada caso. Uno de los principales problemas es la pérdida de masa ósea, que puede ser causada por la reabsorción de hueso, fracturas o extirpación de tumores; en estos casos el tratamiento requiere de un material de relleno óseo. Se espera que este material de relleno sea capaz de promover la regeneración de hueso; los materiales que cumplen con este requisito se les denomina injertos óseos. Otras aplicaciones de los injertos óseos son el aumento de hueso para corregir deformaciones o para fijar implantes dentales u ortopédicos. Se estima que en Europa los sustitutos óseos se utilizan en un millón de cirugías anualmente. El mercado mundial de estos materiales se estima en cinco billones de Euros con una tasa de crecimiento anual de 8-15 %.
La hidroxiapatita, que corresponde a la fase mineral de hueso y dientes, es uno de los mejores materiales utilizados en el desarrollo de injertos óseos sintéticos. Las bioactividad y osteoconductividad de la hidroxiapatita son la razón de su éxito. Sin embargo, la hidroxiapatita es relativamente estable, por ello, los bloques sólidos no son reabsorbidos a largo plazo. Para incrementar la reabsorción de la hidroxiapatita, y permitir la formación de nuevo hueso hacia su interior, se incorporan macroporos abiertos en el material, mejorando también la osteointegración del implante. Un método para conseguir lo anterior es el espumado de los cementos de fosfatos de calcio; este enfoque tiene la ventaja de que la hidroxiapatita obtenida después del fraguado del cemento es más similar a la hidroxiapatita biológica que las hidroxiapatitas sinterizadas. Además, debido a que los cementos son inyectables cuando son una pasta, es posible obtener injertos óseos inyectables, macroporosos y autoconsolidables.
El objetivo de la presente tesis es desarrollar espumas sólidas de hidroxiapatita a través del método de espumado de la fase líquida de un cemento de fosfato de calcio. Se espera que las espumas obtenidas puedan ser utilizadas como injertos óseos inyectables y autoconsolidables bajo condiciones fisiológicas. A lo largo de la tesis se estudian dos tipos de agentes espumantes. En primer lugar, el surfactante no iónico Tween 80 se estudia como agente espumante sintético, en segundo lugar, la gelatina, el alginato de sodio y el extracto de soja se estudian como agentes espumantes naturales. Estos polímeros se proponen como agentes espumantes con la intención de obtener espumas compuestas que imiten la composición y la estructura del nanocompuesto natural que es el tejido óseo.
Los resultados mostraron que es posible obtener espumas inyectables de hidroxiapatita empleando contenidos de Tween 80 por debajo de la dosis máxima recomendada en administración parenteral. También se comprobó que la gelatina y el extracto de soja permiten obtener espumas inyectables y autofraguables in situ. Por el contrario, el alginato de sodio no mostró ser un buen agente espumante. Al comparar los dos tipos de agentes espumantes estudiados (sintético y natural) se puede concluir que el espumante sintético Tween 80 es más eficiente que los espumantes naturales; no obstante, la gelatina y el extracto de soja mejoran la Inyectabilidad y/o la cohesión de las espumas, ambas propiedades indispensables para utilizar estos materiales como injertos óseos inyectables y autoconsolidables.
Los estudios in vitro e in vivo mostraron que las espumas obtenidas de hidroxiapatita no son toxicas, que pueden ser preparadas bajo condiciones estériles dentro del quirófano sin equipos especiales, y que las espumas seleccionadas tienen cohesión para endurecer in situ bajo condiciones fisiológicas, adaptando la forma y rellenando perfectamente el defecto cuando son implantadas por inyección.
Nowadays, there are great number of injuries and illnesses that affect bone tissue. The origin of these diseases is diverse and their treatment is also different in each case. A great problem is bone loss, which can be caused by bone resorption, fractures or bone tumor extirpation; in these cases, a bone filler material will be required. It is expected that the filling material should be able to promote bone healing; materials that meet this properties are known as bone grafts. Other applications of bone grafting materials are the bone mass augmentation to correct deformations or to fix dental and orthopedic implants. It is estimated that in Europe bone substitutes are used in one million surgical procedures annually. The worldwide market of these materials is an estimated of five billion Euros with annual growth rate of 8-15%.
One of the most successful materials used in the development of synthetic bone grafting materials is hydroxyapatite, which correspond to the mineral phase of bone and teeth. The bioactivity and the osteoconductivity properties of hydroxyapatite are the reasons of its success. Nevertheless, hydroxyapatite is relatively stable; therefore, solid blocks are not resorbed in the long term. In order to increase the hydroxyapatite resorption, and allow new bone ingrowth, open macropores are incorporated to the material, improving also implant osteointegration. One method to do this is by foaming calcium phosphate cements; this approach has the advantage that the resulting hydroxyapatite after cement setting is more similar to the biological apatite than sintered hydroxyapatite. In addition, since bone cements are injectable when they are a paste, it is possible to develop an injectable, macroporous, and self-setting bone graft.
The objective of this thesis was to develop solid hydroxyapatite foams through the liquid phase foaming of a calcium phosphate bone cement. It is expected that the developed foams can be applied as injectable, self-setting, synthetic bone grafts under physiological conditions. Along with this thesis, two types of foaming agent were studied. In first place, non ionic surfactant Tween 80 was tested as syntactic foaming agent; and second, gelatin, sodium alginate and soy extract were tested as natural foaming agents. These biopolymers are proposed as foaming agents with the objective of obtaining composite foams that mimic the composition and structure of the natural nanocomposite that is bone tissue.
The results showed that is possible to obtain injectable hydroxyapatite foams using Tween 80 amounts below the maximum dosage recommended for parenteral administration. Also, it was validated that gelatin and soy extract allow obtaining injectable, in situ self-setting foams. In contrast, sodium alginate did not show a good foaming capacity. Comparing the two types of studied foaming agents (synthetic and natural) it can be concluded that the synthetic foaming agent Tween 80 is more efficient than the natural foaming agents; however, gelatin and soy extract improved the injectability and/or the cohesion of the foams, both essential properties to use these materials as injectable and self-setting grafts.
The in vitro and in vivo studies showed that the hydroxyapatite foams obtained were not toxic, they could be prepared under sterile conditions in the operating room without special staff, and the selected foams maintained their cohesion to set in situ under physiological conditions, adapting and filling perfectly the shape of the defect when implanted through injection.

In this dissertation different van der Waals heterostructures such as graphene-MoS2 and MoTe2-MoS2 were prepared and characterized. In the first heterostructure, polycrystalline graphene was synthesized by chemical vapor deposition and transferred on top of MoS2 single crystal. In the second heterostructure, MoTe2 monolayers were deposited on MoS2 by molecular beam epitaxy. Characterization of graphene-MoS2 heterostructures was conducted by spin and angle resolve spectroscopy which showed that the electronic structure of the bulk MoS2 and graphene in this van der Waals heterostructures is modified. For MoS2 underneath the graphene, a band structure renormalization and spin polarization are observed. The band structure of MoS2 is modified because the graphene induces screening which shifts the Г-point ~150 meV to lower binding compared to the sample without graphene. The spin polarization is explained by the dipole arising from band bending which breaks the symmetry at the MoS2 surface. For graphene, the band structure at lower binding energy shows that the Dirac cone remains intact with no significant doping. Instead, away from the Fermi level the formation of several gaps in the pi-band due to hybridization with states from the MoS2 is observed. For the heterostructures made depositing monolayer of MoTe2 on MoS2, the morphology, structure and electronic structure were studied. Two dimensional growth is observed under tellurium rich growth conditions and a substrate temperature of 200 °C but formation of a complete monolayer was not achieved. The obtained MoTe2 monolayer shows a high density of the mirror-twins grain boundaries arranged in a pseudo periodic wagon wheel pattern with a periodicity of ~2.6 nm. These grain boundary are formed due to Te-deficiency during the growth. The defect states from these domain boundary pin the Fermi level in MoTe2 and thus determine the band alignment in the MoTe2-MoS2 heterostructures.

Gamma-aminobutyric acid (GABA) is a key neurotransmitter for reproductive control. A major site for the control of GABA synthesis is the regulation of synthesis and activity of glutamic acid decarboxylase (GAD), which exists in three isoforms in goldfish. Previous sequence data suggested that GAD65 and GAD67 originated prior to teleost divergence. We have shown that this event occurred prior to 450 million years ago, before the emergence of Chondrichthyes. Previous data showed that estradiol and testosterone modulate GAD65 and GAD67 mRNA levels in sexually regressed goldfish brain. No previous data are available on the regulation of GAD3 in any animal. We found that levels of all three GADS vary seasonally. Steroid administration of testosterone, progesterone and estradiol had seasonal, brain-region and sex specific effects. This is the first evidence for seasonal variations in GAD3 and we show a likely role for progesterone in down-regulating GAD 65 and GAD67 in goldfish brain.

This study investigated the behaviour of re-gifting using both qualitative and quantitative research methods. Re-gifting is the gift-giving behaviour of giving a gift that was previously given to you, to another with the pretence that you purchased the gift. The qualitative phase used semi-structured interviews to uncover an initial understanding of re-gifting behaviour from participants’ selected using purposive sampling. The main findings arising from this phase showed that re-gifters used three main factors to determine when it is appropriate to re-gift. These three factors, relationship, occasion and gift were used as the basis of the conceptual framework. This framework was then analysed using an online experiment with the use of vignette techniques which was the focus of the quantitative phase. The study focused on understanding what influences individuals decisions to re-gift. The main factors of interest were how the gift, occasion and relationships involved influenced re-gifting intentions. Re-gifting attitudes where analysed using the factors gift-giving attitudes, previous re-gifting experiences and frequency of re-gifting. A total of 211 responses were collected from Web users from around the world. The study suggests that re-gifters are influenced by the relationships involved and the type of gift, not the occasion. Re-gifting attitudes can be influenced by previous re-gifting experiences. This study has numerous practical implications, more specifically for retailers and charity organisations. This study adds major contributions to both gift-giving and disposition literature and introduces the area of re-gifting. Future research in cultural differences, gender differences and re-gifters versus non re-gifters suggested.

En robotique, il a toujours été difficile pour une jambe ou un bras robotique d'interagir avec son environnement, si ce dernier est inconnu. Les interactions non désirées peuvent causer de sérieux dommages au robot ou à l'environnement, ce qui est encore plus critique si l'environnement implique la présence d'un être humain. Les robots marcheurs sont sujets à ces mêmes contraintes lorsqu’il s'agit de se déplacer en terrains irréguliers et inconnus. Bien que leurs jambes permettent de s'adapter aux surfaces accidentées et de franchir des obstacles, les contacts avec le sol peuvent générer d'importantes forces. Percevoir les contacts avec le sol ainsi que les forces engendrées permettent un contrôle plus approprié du système robotique. Bien qu'il soit possible de munir les pattes de robots de capteurs de contact et de force, il reste que tout choc se répercute sur les engrenages des actionneurs, avec le risque de les endommager. Une autre solution consiste à utiliser des actionneurs élastiques compilants, i.e. des actionneurs munis d'un élément élastique qui permettent d'amortir les chocs et de percevoir les couples appliquées et retournées par l'environnement. Dans le présent travail, nous nous intéressons à l'utilisation d'actionneurs différentiel élastique (ADE) pour la réalisation d'une articulation pour une jambe de robot. L'ADE est un actionneur qui peut permettre une haute densité de couple, avec une impédance mécanique intrinsèque faible et qui peut être contrôlé en force, donc capable d'interactions sécuritaires avec son environnement. Afin de minimiser les dimensions et le poids de l'articulation tout en maximisant le couple et la vitesse, nous avons choisi d'étudier le couplage de deux ADE à travers un différentiel mécanique permettant l'élévation et la rotation d'une jambe de robot. Ainsi, il est possible d'utiliser le couple déployé par les deux actionneurs pour chacun des degrés de liberté, au lieu d'exploiter les capacités d'un seul actionneur par degré de liberté. L'analyse des résultats démontre un bon comportement au niveau du couple et de la vitesse dans les deux degrés de liberté du différentiel. L'intégration préliminaire de l'articulation pourra être utilisée pour étudier le comportement d'un robot marcheur à huit degrés de liberté dans des conditions d'utilisation variées (e.g., charge [i.e. charges] variables, terrains irréguliers).

This thesis investigates how breaking apart selection interference (‘Hill-Robertson’ effects) that arises between linked loci can select for higher levels of recombination. Specifically, it mainly studies how the presence of both advantageous and deleterious mutation affects selection for recombination. These evolutionary advantages are subsequently investigated with regards to sex resisting asexual invasion in a subdivided population. i) KEIGHTLEY and OTTO (2006) showed a strong advantage to recombination in breaking apart selection interference, if it acts across multiple, linked loci subject to recurrent deleterious mutation. Their model is modified to consider selection acting on recombination if a small proportion of mutations are advantageous. This leads to a greater increase in selection acting on a recombination modifier, compared to cases where only deleterious mutations are present. ii) Branching-process methods are developed to quantify how likely it is that a deleterious mutant hitchhikes with a selective sweep, and how recombination between the two loci affects this process. This is compared to the neutral hitchhiking model, to determine how levels of linked neutral diversity would differ between the two scenarios. A simple application with regards to human genetic data is provided. iii) Population subdivision can maintain costly sex, as a consequence of restricted gene flow slowing the spread of invading asexuals, which leads to an excessive accumulation of deleterious alleles. However, previous work did not quantify whether costly sex can be maintained with realistic levels of population subdivision. Simulations in this thesis show that the level of population subdivision (as measured by Fst) needed to maintain costly sex decreases with larger population size; however critical Fst values found are generally high, compared to surveys of geographicallyclose populations. The lowest levels of population subdivision that maintained sex were found if mutation is both advantageous and deleterious, and demes were arranged in a one-dimensional stepping-stone formation. iv) An analytical method is developed to calculate how long it takes an advantageous mutation (such as an invading asexual) to spread through a subdivided population. The flexibility of the methods created means that they can be applied to different types of stepping-stone populations. It is shown how to formulate the fixation time for one-dimensional and two-dimensional structures, with analytical methods showing a good fit to simulation data.

Dissertação para obtenção do Grau de Mestre em Genética Molecular e Biomedicina
The main objective of the work presented in this thesis was to develop a gene silencing system by taking advantage of the nanovectorization capability and optical properties of gold nanoparticles. The idea is based on the construction of a DNA structure containing a therapeutic oligonucleotide with the ability to form Hoogsteen hydrogen bonds with double-stranded DNA, producing a DNA triple helix, besides silencing the gene of interest. Hoogsteen bonds, more unstable than the conventional Watson-Crick bonds, permit the achievement of lower melting temperatures. This attribute, coupled with the ability to generate heat by laser irradiation of the gold nanoparticles used, will allow the release of the therapeutic oligonucleotide and subsequent gene silencing without significant increase in the medium’s temperature. Thus, the thesis comprises three major sections: structure design and formation, vectorization, and gene expression silencing; the tasks involved in each of these sections were conducted in parallel. The design of the obtained structure took into account the desired melting temperature, stability at physiological conditions of the sequence-forming nucleotides, the number of Hoogsteen bonds and ionic conditions. To evaluate the formation of this structure, spectroscopic techniques were mainly used: FRET analysis and ultraviolet melting curves. Both approaches allowed the identification of interactions in the presence of therapeutic oligonucleotide compared with its absence, which may indicate structure formation. In addition, melting curves allowed the determination of the temperature of release of this oligonucleotide – 40ºC. The double-stranded DNA functionalization to gold nanoparticles has been achieved, but there was no difference in electrophoretic migration when the three oligonucleotides were present. However, the therapeutic oligonucleotide was able to efficiently inhibit gene expression in in vitro transcription and translation assays with efficiency up to 95% and 60% respectively.

Dissertação de Mestrado Integrado em Medicina Veterinária
O estudo e o conhecimento das doenças que afectam as espécies silvestres cada vez ganham mais relevância, não só pela manutenção de um bom estado sanitário destas populações mas também pelo potencial zoonótico. O estudo foi composto pelo acompanhamento do acto venatório de gamos (n = 17) e de javalis (n = 9), bem como pela colheita mensal de fezes de populações de veado (n = 1), de gamo (n = 7) e de javali (n = 3) durante o período de um ano. Nos animais caçados foi efectuada a pesquisa de ectoparasitas e endoparasitas gastrointestinais, pulmonares e hepáticos, bem como a coprologia dos mesmos. Nas populações foram efectuados os testes de flutuação de Willis, McMaster e coprocultura para nemátodes gastrointestinais, sedimentação simples e McMaster modificado para Fasciola hepatica, esfregaço fecal para Cryptosporidium nos cervídeos e Baerman para determinação de nemátodes pulmonares. Nos gamos caçados foram detectados as espécies Oesophagostomum venulosum (12,5%) e Oe. radiatum (6,25%), Spiculoteragia asymmetrica (11,76%), S. mathevossiani (5,88%), Spiculopteragia spp. (5,88%), Fasciola hepatica (76,47%) e Ixodes ricinus (88,24%). Nos javalis caçados foram detectadas as espécies Ascarops strongylina (22,22%), Oesophagostomum spp. (12,5%), Metastrongylus spp. (11,11%), M. pudendotectus (11,11%), M. salmi (44,44%), M. elongatus (11,11%), Fasciola hepatica (55,56%), Hyalomma lusitanicum (77,78%) e Rhipicephalus sanguineus (11,11%). No veado foram obtidos dois espécimes de Trichuris spp. Nas análises coprológicas verificou-se a presença de nemátodes gastrointestinais em todas as populações, não tendo existido evidência de uma dinâmica anual de excreção tal como existe nos animais domésticos. Nos gamos, o teste de Baerman detectou L1 de Dictyocaulus, Protostrongylus e Muellerius em todas as populações excepto G3 onde só foram identificados os dois últimos géneros referidos. O último género referido é a primeira vez que é assinalado em gamos na Europa. Nos javalis verificou-se a presença de ovos com L1 de Metastrongylus nas três populações estudadas. A pesquisa de Cryptosporidium foi positiva em apenas duas amostras das populações (2,5% do total das amostras), sendo uma de veado e outra de gamo revelando um decréscimo muito acentuado em relação ao último estudo realizado na Tapada Nacional de Mafra (TNM) por Bruno de Sousa em 2001. Fasciola hepatica continua a ser a maior preocupação sanitária nas populações de ungulados da TNM, estando presente em todas as populações, tendo no entanto maior relevância nos gamos. A combinação da técnica de sedimentação simples com o McMaster modificado, permitiu não só um melhor diagnóstico de Fasciola hepatica como ainda a quantificação da eliminação de ovos.
ABSTRACT - The study and knowledge of diseases affecting wild species has become increasingly more important, not only for maintaining a good health status of these populations but also for their zoonotic potential. The research was composed by monitoring the deer (n = 17) and wild boars (n = 9) hunting and faeces sampling collecting of red deer populations (n = 1), fallow deer (n = 7) and wild boar (n = 3) during the period of one year. In the hunted animals was performed a collection of ectoparasites and gastrointestinal, pulmonary and liver endoparasites, as well as coprology. In populations Willis flotation, McMaster and faecal cultures for gastrointestinal nematodes, simple sedimentation and modified McMaster to Fasciola hepatica, fecal smears for Cryptosporidium in cervids and Baerman for determination of lung nematodes were conducted. The species detected in hunted deer were Oesophagostomum venulosum (12,5%) and Oe. radiatum (6,25%), Spiculoteragia asymmetrica (11,76%), S. mathevossiani (5,88%), Spiculopteragia spp. (5,88%), Fasciola hepatica (76,47%) and Ixodes ricinus (88,24%). The species detected in hunted wild boars were Ascarops strongylina (22,22%), Oesophagostomum spp. (12,5%), Metastrongylus spp. (11,11%), M. pudendotectus (11,11%), M. salmi (44,44%), M. elongatus (11,11%), Fasciola hepatica (55,56%), Hyalomma lusitanicum (77,78%) and Rhipicephalus sanguineus (11,11%). In the red deer were collected two specimens of Trichuris spp. In faecal analysis the presence of gastrointestinal nematode in all populations was confirmed; however there was not an evidence of an annual dynamic for egg shedding excretion as found in domestic animals. In fallow deer, the Baerman test detected L1 of Dictyocaulus, Protostrongylus and Muellerius in all populations except G3 where were identified only the last two mentioned genus. The last genus was reported for the first time in fallow deer in Europe. In wild boars eggs with L1 larvae of Metastrongylus were observed. Cryptosporidium was positive in only two population samples (2,5% os total samples) being one of red deer and the other of fallow deer revealing a very sharp decrease since the previous study conducted in the Tapada Nacional de Mafra (TNM) by Bruno de Sousa in 2001. Fasciola hepatica remains the biggest health concern in the TNM ungulates, because it is present in all populations, however having greater relevance in fallow deer. The combination of simple sedimentation technique with the modified McMaster helped in better diagnosis of Fasciola hepatica, and allowed a better quantification of the egg shedding.

Tesis - Maestría en Salud Materno Infantil - Universidad Nacional de Córdoba. Facultad de Ciencias Médicas. Secretaria de Graduados en Ciencias de la Salud, 2015 71 h. : gráf., 29 cm.
Fil: Gómez, Mariana Virginia. Universidad Nacional de Córdoba. Facultad de Ciencias Médicas. Secretaría de Graduados. Maestría en Salud Materno infantil; Argentina.
introducción: El tema de la presente investigación es “Prácticas alimentarias que favorecen la absorción del hierro en embarazadas”. El objetivo fue identificar prácticas alimentarias que contribuyen a la absorción del hierro no heme, favoreciendo la prevención de la anemia ferropenica en mujeres embarazadas. Resultados y conclusiones: En base a lo analizado podemos concluir que las prácticas alimentarias que favorecen la absorción del hierro no heme de los alimentos realizadas por éste grupo de embarazadas son: El no consumo de café y té luego de las comidas; El tiempo de guardado de los vegetales por menos de una semana; y El lugar de guardado de vegetales en la heladera; En cambio, las prácticas que no se llevan a cabo, por lo que se dificulta la absorción del hierro no heme son: Consumo diario de carnes; Elección del vapor como método de cocción; El consumo de verduras amarillas, anaranjadas, blancas y rojas diario; El guardado de vegetales en bolsas o papel para evitar la oxidación de los nutrientes; y La combinación de legumbres y vegetales verdes con cítricos para asegurar una completa absorción del hierro no heme.
The subject of this research is "Feeding practices that favor the absorption of iron in pregnant". The aim was to identify dietary practices that contribute to the absorption of non heme iron, favoring the prevention of iron deficiency anemia in pregnant women. Results and conclusions: Based on the analyzed can conclude that dietary practices that promote the absorption of nonheme food made by this group of pregnant are: no drinking coffee and tea after meals; The time saved from vegetable for less than a week; The storage location and vegetables in the refrigerator; Instead, the practices are not carried out, so that iron absorption is difficult not heme are meat daily consumption; Election of steam as a cooking method; The consumption of yellow vegetables, orange, white and red diary; The plant kept in bags or paper to prevent oxidation of nutrients; Combining legumes and green vegetables and citrus to ensure complete absorption of nonheme iron.