Spike-timing dependent plasticity and connectivity in primate sensorimotor cortex

Thesis (Ph.D.)--University of Washington, 2016-06

Timing ótimo para investir na proteção costeira na zona centro de Portugal

A presente dissertação insere-se no âmbito da gestão das zonas costeiras, que na atualidade enfrentam um grave problema de erosão. Este torna-se um problema social com especial importância devido à concentração populacional e atividade económica que se verifica nas regiões litorais. Neste contexto muitos têm sido os estudos físicos e económicos levados a cabo no sentido de encontrar soluções para lidar com este problema. O principal objetivo desta dissertação foi avaliar qual a importância que o timing em que é efetuado o investimento na proteção pode ter na defesa das zonas costeiras. Por outras palavras, perceber se existem ou não vantagens em adiar o investimento na proteção por um determinado período de tempo. Foi definida como área de estudo o trecho costeiro de 20 km compreendido entre a Praia da Barra (Aveiro) e a Praia de Mira (Coimbra). Através da utilização do modelo numérico Long-Term Configuration (LTC) foi simulada a evolução da linha de costa por um período de 80 anos, seguida de uma análise custo-benefício ambiental em que foi considerada a possibilidade de investimentos em estruturas de defesa (no caso desta dissertação esporões com 100m, 200m e 300m de comprimento) a serem efetuados após 0, 10, 20 ou 30 anos. Foram também contempladas restrições orçamentais, e ainda, efetuada uma análise de sensibilidade à taxa de desconto utilizada. Os resultados mostram que quanto mais cedo se iniciar proteção das zonas costeiras, mais benefícios económicos serão retirados desse investimento. Os cenários que se apresentaram como os mais vantajosos são aqueles em que o investimento é levado a cabo no Ano 0 e onde se opta por uma proteção integral ou quase integral da linha de costa. Ainda assim, em todos os timings de investimento analisados foi possível encontrar cenários economicamente viáveis e dos quais resultariam benefícios económicos. A análise com inclusão de restrições orçamentais mostra que a utilização destas deixa de fazer sentido à medida que o investimento é adiado, funcionando então o próprio retardar do investimento como uma medida de contenção orçamental. A análise de sensibilidade à taxa de desconto revelou que a opção por uma taxa de desconto de 4% acaba por não influenciar de maneira significativa os resultados obtidos.

The multistage crystallization of zircon in calc-alkaline granitoids : U-Pb age constraints on the timing of Variscan tectonic activity in SW Iberia

CL imaging and U–Th–Pb data for a population of zircons from two of the Évora Massif granitoids (Ossa-Morena Zone, SW Iberia) show that both calc-alkaline granitoids have zircon populations dominated by grains with cores and rims either showing or not showing differences in Th/U ratio, and having ages in the range ca. 350–335 Ma (Early Carboniferous). Multistage crystallization of zircon is revealed in two main growth stages (ca. 344–342 Ma and ca. 336–335 Ma), well represented by morphologically complex zircons with cores and rims with different ages and different Th/U ratios that can be explained by: (1) crystallization from melts with different compositions (felsic peraluminous to felsic-intermediate metaluminous; 0.001 Th/U ratio < 0.5) and (2) transient temperature fluctuations in a system where anatectic felsic melts periodically underwent injection of more mafic magmas at higher temperatures. The two studied calc-alkaline granitoids do not include inherited zircons (pre-Carboniferous), probably because they were formed at the highest grade of metamorphism (T 837 °C; granulite facies) and/or because they were derived from inheritance-poor felsic and mafic rocks from a previous cycle, as suggested by the internal structures of zircon cores. These Variscan magmatic rocks with crystallization ages estimated at ca. 336–335 Ma are spatially and temporally related to high-temperature metamorphism, anatexis, processes of interaction between crustal- and mantle-derived magmas and intra-orogenic extension that acted in SW Iberia during the Early Carboniferous.

Non-contact test set-up for aeroelasticity in a rotating turbomachine combining a novel acoustic excitation system with tip-timing

Due to trends in aero-design, aeroelasticity becomes increasingly important in modern turbomachines. Design requirements of turbomachines lead to the development of high aspect ratio blades and blade integral disc designs (blisks), which are especially prone to complex modes of vibration. Therefore, experimental investigations yielding high quality data are required for improving the understanding of aeroelastic effects in turbomachines. One possibility to achieve high quality data is to excite and measure blade vibrations in turbomachines. The major requirement for blade excitation and blade vibration measurements is to minimize interference with the aeroelastic effects to be investigated. Thus in this paper, a non-contact-and thus low interference-experimental set-up for exciting and measuring blade vibrations is proposed and shown to work. A novel acoustic system excites rotor blade vibrations, which are measured with an optical tip-timing system. By performing measurements in an axial compressor, the potential of the acoustic excitation method for investigating aeroelastic effects is explored. The basic principle of this method is described and proven through the analysis of blade responses at different acoustic excitation frequencies and at different rotational speeds. To verify the accuracy of the tip-timing system, amplitudes measured by tip-timing are compared with strain gage measurements. They are found to agree well. Two approaches to vary the nodal diameter (ND) of the excited vibration mode by controlling the acoustic excitation are presented. By combining the different excitable acoustic modes with a phase-lag control, each ND of the investigated 30 blade rotor can be excited individually. This feature of the present acoustic excitation system is of great benefit to aeroelastic investigations and represents one of the main advantages over other excitation methods proposed in the past. In future studies, the acoustic excitation method will be used to investigate aeroelastic effects in high-speed turbomachines in detail. The results of these investigations are to be used to improve the aeroelastic design of modern turbomachines.

Effect of haptic guidance and error amplification robotic training interventions on the immediate improvement of timing among individuals that had a stroke

Abstract : Many individuals that had a stroke have motor impairments such as timing deficits that hinder their ability to complete daily activities like getting dressed. Robotic rehabilitation is an increasingly popular therapeutic avenue in order to improve motor recovery among this population. Yet, most studies have focused on improving the spatial aspect of movement (e.g. reaching), and not the temporal one (e.g. timing). Hence, the main aim of this study was to compare two types of robotic rehabilitation on the immediate improvement of timing accuracy: haptic guidance (HG), which consists of guiding the person to make the correct movement, and thus decreasing his or her movement errors, and error amplification (EA), which consists of increasing the person’s movement errors. The secondary objective consisted of exploring whether the side of the stroke lesion had an effect on timing accuracy following HG and EA training. Thirty-four persons that had a stroke (average age 67 ± 7 years) participated in a single training session of a timing-based task (simulated pinball-like task), where they had to activate a robot at the correct moment to successfully hit targets that were presented a random on a computer screen. Participants were randomly divided into two groups, receiving either HG or EA. During the same session, a baseline phase and a retention phase were given before and after each training, and these phases were compared in order to evaluate and compare the immediate impact of HG and EA on movement timing accuracy. The results showed that HG helped improve the immediate timing accuracy (p=0.03), but not EA (p=0.45). After comparing both trainings, HG was revealed to be superior to EA at improving timing (p=0.04). Furthermore, a significant correlation was found between the side of stroke lesion and the change in timing accuracy following EA (r[subscript pb]=0.7, p=0.001), but not HG (r[subscript pb]=0.18, p=0.24). In other words, a deterioration in timing accuracy was found for participants with a lesion in the left hemisphere that had trained with EA. On the other hand, for the participants having a right-sided stroke lesion, an improvement in timing accuracy was noted following EA. In sum, it seems that HG helps improve the immediate timing accuracy for individuals that had a stroke. Still, the side of the stroke lesion seems to play a part in the participants’ response to training. This remains to be further explored, in addition to the impact of providing more training sessions in order to assess any long-term benefits of HG or EA.

Home Literacy Activities in Latino Immigrant Families: Contributions to Toddlers’ Expressive and Receptive Language Skills

The development of language is a critical component of early childhood, enabling children to communicate their wishes and desires, share thoughts, and build meaning through linguistic interactions with others. A wealth of research has highlighted the importance of children’s early home experiences in fostering language development. This literature emphasizes the importance of a stimulating and supportive home environment in which children are engaged in literacy activities such as reading, telling stories, or singing songs with their parents. This study examined the association between low-income Latino immigrant mothers’ and fathers’ home literacy activities and their children’s receptive and expressive language skills. It also examined the moderating influence of maternal (i.e., reading quality and language quality) and child (engagement during reading, interest in literacy activities) characteristics on this association. This study included observational mother-child reading interactions, child expressive and receptive language assessments, and mother- and father-reported survey data. Controlling for parental education, multiple regression analyses revealed a positive association between home literacy activities and children’s receptive and expressive language skills. The findings also revealed that mothers’ reading quality and children’s engagement during reading (for expressive language skills only) moderated this association. Findings from this study will help inform new interventions, programs, and policies that build on Latino families’ strengths.

The timing and interval of mate encounter affects investment during mating

The benefits obtained from mating are usually condition-dependent, favouring the evolution of flexible investment during copulation, for instance, in terms of invested time, energy, or sperm. Flexible investment strategies are predicted to depend on the likelihood of acquiring alternative mates and therefore they should depend on the timing of mate encounter. However, scarce experimental evidence for this hypothesis exists. Here we manipulated the time delay until first mating and the interval between first and second mating in the polygynandrous common lizard, Zootoca vivipara. We determined treatment effects on fertilisation success and copulation duration, the latter being a proxy for investment in mating and for quantity of transferred sperm. The duration of the second copulation decreased with increasing inter-mating interval and depended on the fertilisation success of first mates. The former provides evidence for time-dependent investment strategies, most likely resulting from the progression of the female's reproductive cycle. Fertilisation success of first mates increased with increasing inter-mating interval and was higher when females were closer to ovulation, showing that flexible investment strategies significantly affected male reproductive success. This points to fertilisation assurance, which may mitigate negative effects of low population density on reproductive success, e.g. Allee effects.

Timing and economic value of mergers and acquisitions

Doctor of Philosophy in the Faculty of Business Administration

Timing versus caloric goal in nutritional therapy for critically ill patients

Introduction: Enteral nutrition is an important therapy for severely critically ill patients. The timing and amount of energy have been highly debated. Objective: The aim of the present study was to directly compare the timing and the caloric targets in critically ill patients. Methods: Retrospective cohort study conducted at a single center, comparing timing and caloric goal for critically ill patients. Patients were stratified according to the start of nutritional therapy (24, 48, or more than 48 h) and the amount of energy delivered (target adequacy of previously calculated percentage in the first week). Statistical analysis was performed using parametric and non-parametric tests for independent samples and logistic regression. The results were expressed as mean ± standard deviation or incidence and percentage. Results and discussion: There were no differences in major clinical outcomes in relation to the achievement of percentage of caloric goal at the end of the first week of the study. The beginning of caloric intake on the first day of hospitalization was associated with reduced mortality in the intensive care unit, but not with hospital mortality. The strategy of an early and limited amount of calories seems to be associated with a better outcome. Prospective studies evaluating and comparing these strategies are recommended.

AN INVESTIGATION OF VARIABLE VALVE TIMING EFFECTS ON HCCI ENGINE PERFORMANCE

The Homogeneous Charge Compression Ignition (HCCI) engine is a promising combustion concept for reducing NOx and particulate matter (PM) emissions and providing a high thermal efficiency in internal combustion engines. This concept though has limitations in the areas of combustion control and achieving stable combustion at high loads. For HCCI to be a viable option for on-road vehicles, further understanding of its combustion phenomenon and its control are essential. Thus, this thesis has a focus on both the experimental setup of an HCCI engine at Michigan Technological University (MTU) and also developing a physical numerical simulation model called the Sequential Model for Residual Affected HCCI (SMRH) to investigate performance of HCCI engines. The primary focus is on understanding the effects of intake and exhaust valve timings on HCCI combustion. For the experimental studies, this thesis provided the contributions for development of HCCI setup at MTU. In particular, this thesis made contributions in the areas of measurement of valve profiles, measurement of piston to valve contact clearance for procuring new pistons for further studies of high geometric compression ratio HCCI engines. It also consists of developing and testing a supercharging station and the setup of an electrical air heater to extend the HCCI operating region. The HCCI engine setup is based on a GM 2.0 L LHU Gen 1 engine which is a direct injected engine with variable valve timing (VVT) capabilities. For the simulation studies, a computationally efficient modeling platform has been developed and validated against experimental data from a single cylinder HCCI engine. In-cylinder pressure trace, combustion phasing (CA10, CA50, BD) and performance metrics IMEP, thermal efficiency, and CO emission are found to be in good agreement with experimental data for different operating conditions. Effects of phasing intake and exhaust valves are analyzed using SMRH. In addition, a novel index called Fuel Efficiency and Emissions (FEE) index is defined and is used to determine the optimal valve timings for engine operation through the use of FEE contour maps.

Determing the Effect of Thermal Treatment Timing on Ultra-High Performance Concrete Beams

The loss of prestressing force over time influences the long-term deflection of the prestressed concrete element. Prestress losses are inherently complex due to the interaction of concrete creep, concrete shrinkage, and steel relaxation. Implementing advanced materials such as ultra-high performance concrete (UHPC) further complicates the estimation of prestress losses because of the changes in material models dependent on curing regime. Past research shows compressive creep is "locked in" when UHPC cylinders are subjected to thermal treatment before being loaded in compression. However, the current precasting manufacturing process would typically load the element (through prestressing strand release from the prestressing bed) before the element would be taken to the curing facility. Members of many ages are stored until curing could be applied to all of them at once. This research was conducted to determine the impact of variable curing times for UHPC on the prestress losses, and hence deflections. Three UHPC beams, a rectangular section, a modified bulb tee section, and a pi-girder, were assessed for losses and deflections using an incremental time step approach and material models specific to UHPC based on compressive creep and shrinkage testing. Results show that although it is important for prestressed UHPC beams to be thermally treated, to "lock in" material properties, the timing of thermal treatment leads to negligible differences in long-term deflections. Results also show that for UHPC elements that are thermally treated, changes in deflection are caused only by external loads because prestress losses are "locked-in" following thermal treatment.

Effects of pubertal status and timing on externalizing behavior problems and anxious/depressed symptoms in a sample of adolescent girls of color

Empirical research has shown that pubertal development is closely linked with adolescent externalizing (e.g., aggressive) and internalizing (e.g., anxiety) problems. In most studies, pubertal timing, pubertal status, or both, are used to examine this link. The present study adds to the existing literature by examining the link between puberty and adolescent behavior problems in a sample of predominantly urban African American adolescent girls. One hundred and seventeen adolescent girls of color, aged 11-18 (M = 14.72 SD = 1.44), and their primary caregiver participated in this study. Sixty-eight percent were African American, 22.2 % were Hispanic/Latina, and 9.4% were Haitian. Among the Hispanic/Latina girls, 9.4% were Black Hispanic/Latina. Results showed that pubertal status and perceived pubertal timing (breasts) are better predictors of externalizing behavior problems than chronological age and quality of relationship with peers. No significant findings were found with anxious/depressed symptoms.

Impact of the timing of metoprolol administration during STEMI on infarct size and ventricular function

Pre-reperfusion administration of intravenous (IV) metoprolol reduces infarct size in ST-segment elevation myocardial infarction (STEMI). This study sought to determine how this cardioprotective effect is influenced by the timing of metoprolol therapy having either a long or short metoprolol bolus-to-reperfusion interval. We performed a post hoc analysis of the METOCARD-CNIC (effect of METOprolol of CARDioproteCtioN during an acute myocardial InfarCtion) trial, which randomized anterior STEMI patients to IV metoprolol or control before mechanical reperfusion. Treated patients were divided into short- and long-interval groups, split by the median time from 15 mg metoprolol bolus to reperfusion. We also performed a controlled validation study in 51 pigs subjected to 45 min ischemia/reperfusion. Pigs were allocated to IV metoprolol with a long (−25 min) or short (−5 min) pre-perfusion interval, IV metoprolol post-reperfusion (+60 min), or IV vehicle. Cardiac magnetic resonance (CMR) was performed in the acute and chronic phases in both clinical and experimental settings. For 218 patients (105 receiving IV metoprolol), the median time from 15 mg metoprolol bolus to reperfusion was 53 min. Compared with patients in the short-interval group, those with longer metoprolol exposure had smaller infarcts (22.9 g vs. 28.1 g; p = 0.06) and higher left ventricular ejection fraction (LVEF) (48.3% vs. 43.9%; p = 0.019) on day 5 CMR. These differences occurred despite total ischemic time being significantly longer in the long-interval group (214 min vs. 160 min; p < 0.001). There was no between-group difference in the time from symptom onset to metoprolol bolus. In the animal study, the long-interval group (IV metoprolol 25 min before reperfusion) had the smallest infarcts (day 7 CMR) and highest long-term LVEF (day 45 CMR). In anterior STEMI patients undergoing primary angioplasty, the sooner IV metoprolol is administered in the course of infarction, the smaller the infarct and the higher the LVEF. These hypothesis-generating clinical data are supported by a dedicated experimental large animal study.

EXPRESSIVE ARTS – EMBODYING INCLUSIVE TEACHERS

The Declaration of Salamanca proposes a deep reformulation of educational praxis which has as a main goal to create an environment where all students can enjoy learning, improve and grow in confidence, in a perspective of Inclusive Education. In this sense, it is necessary that teachers acquire scientific and educational skills but, also, development of personal and interpersonal competences that are crucial for a flexible and adequate professional praxis. The concept of competences integrates knowledge, skills, personal values and attitudes that are acquired through work experience and learning by doing. On other side, experiential work is lived through a body in movement. Acknowledging these ideas and considering active methods and expressive arts as valorous contributions to the positive model of inclusive education in this paper, the authors propose the training in Expressive Arts to promote Inclusion but mainly to develop personal and interpersonal competences of teachers to the Inclusion