A fairly large portion of patients receiving surgical or intensive care will need mechanical ventilation at some point. The potential ventilator-induced lung injury (VILI) is thus of interest. One of the main causal factors in VILI is the cyclic energy shifts, i.e. tidal volumes, in the lung during mechanical ventilation. The problem can be approached in two ways. Firstly, one can utilize apneic oxygenation and thus not cause any tidal injuries at all. Secondly, and more traditionally, one can simply lower the tidal volumes and respiratory rates used. The following describes a series of animal experiments exploring these options. In the first two papers, I explored and improved upon the methodology of apneic oxygenation. There is a generally held belief that it is only possible to perform apneic oxygenation by prior denitrogenation and by using 100% oxygen during the apnea. As 100% oxygen is toxic, this has prevented apneic oxygenation from more widespread use. The first paper proves that it is indeed possible to perform apneic oxygenation with less than 100% oxygen. I also calculated the alveolar nitrogen concentration which would conversely give the alveolar oxygen concentration. The second paper addresses the second large limitation of apneic oxygenation, i.e. hypercapnia. Using a high dose infusion of tris(hydroxymethyl)aminomethane (THAM) buffer, a pH > 7.2 could be maintained during apneic oxygenation for more than 4.5 hours. In the last two papers, THAM’s properties as a proton acceptor are explored during respiratory acidosis caused by very low volume ventilation. In paper III, I found that THAM does not, in the long term, affect pH in respiratory acidosis after stopping the THAM infusion. It does, however, lower PVR, even though the PaCO2 of THAM-treated animals had rebounded to levels higher than that of the controls. In the last experiment, I used volumetric capnography to confirm our hypothesis that carbon dioxide elimination through the lungs was lower during the THAM infusion. Again, the PaCO2 rebounded after the THAM infusion had stopped and I concluded that renal elimination of protonated THAM was not sufficient.

Student Number : 0001367T - MA dissertation - School of Architecture and Planning - Faculty of Humanities / This is an exploratory study which seeks to look at barriers to land accessibility for the construction of low-income or affordable housing on former mining lands between Soweto and Johannesburg CBD. Based on the findings, there are various barriers which inhibit and threaten the construction of houses on former mining lands. These barriers, exposed by the findings of this report are radon, mine dust - both of which pose a serious health risk to residents if exposed to it for a long period of time - high prices of land, inadequate funding for housing subsidies and the National Nuclear Regulator’s too strict and uncompromising stance on housing construction on contaminated lands. The conclusion drawn by this report is that the government, owners of former mining land and the National Nuclear Regulator need to co-operate and work together towards finding a common ground in order to enhance the possibility of a total removal of these barriers, so that the previously marginalized citizens can afford to own houses closer to the Central Business District of Johannesburg.

This study investigates the effects of forestry on leaf litter decomposition in small forest streams. Riparian forest, that is the land closest to the stream, maintain shading, water temperature and energy supply through litter fall. If the riparian zone is deforested, many riparian functions important for the integrity of the stream ecology, hydrology and biogeochemistry can be lost or modified. Leaf litter decomposition can be used as an integrated measure of the physical and biological changes following forestry perturbations.  This study was conducted in 11 northern and 12 southern Swedish streams to address; 1) How is leaf litter decomposition in small streams affected by forestry by measuring leaf litter decomposition in streams with different buffer widths, and; 2) How other environmental variables, such as  stream bottom substrate, canopy openness, water temperature and stream velocity affected leaf litter decomposition. Buffer width had no effect on decomposition. Temperature and proportion organic bottom substrate had respectively positive and negative trends with decomposition in the southern Swedish sites which suggests the importance of forestry targeting these riparian functions especially when managing small streams. At the northern sites, velocity showed a positive, and temperature a negative trend with leaf litter decomposition but none of these were significant. It is possible that the extraordinarily warm and dry weather before and during the study was conducted affected aquatic organisms to the degree that decomposition was inhibited, and most trends became too small to detect or that buffer width is less important in a warmer climate.

As algas marinhas calcárias (AMC) e os óleos essenciais vêm sendo utilizados como aditivos em dietas para ruminantes. As AMC têm sido adicionadas às dietas com o objetivo de modularem o pH ruminal, enquanto os óleos essenciais, através de sua ação antimicrobiana, têm sido testados como alternativa aos aditivos antibióticos na produção animal. Os objetivos do presente estudo foram avaliar os efeitos de óleos essenciais e de algas marinhas calcárias (AMC), bem como a combinação de ambos, sobre desempenho e ambiente ruminal de vacas leiteiras em lactação. Foram realizados 2 experimentos com 32 vacas leiteiras sob sistema de pastejo rotativo com suplementação diária de 6 kg de alimento concentrado por vaca: o experimento 1 foi de desempenho e o experimento 2 de metabolismo ruminal. Em ambos os experimentos as vacas foram submetidas aos seguintes tratamentos: a) controle (CONT); b) óleos essenciais (OE); c) algas marinhas calcárias (AMC); d) AMC + OE. No experimento 1, as variáveis registradas foram consumo, produção e composição do leite, ganho de peso, condição corporal e parâmetros sanguíneos (glicose e ácidos graxos não esterificados [AGNE]). No experimento 2 foram utilizadas as mesmas 32 vacas em lactação para avaliação dos parâmetros ruminais. Os delineamentos utilizados foram: em quadrados latinos replicados (experimento 1) e em blocos inteiramente casualizados (experimento 2). No experimento 1 o CMS de pasto e os CMS e CMO totais foram maiores para o tratamento AMC em comparação com os tratamentos OE e OE+AMC. Os dados de consumo do tratamento CONT foram não diferiram dos demais tratamentos. As digestibilidades da MS e da MO foram maiores para os tratamentos OE e OE+AMC em comparação com o tratamento AMC. Os dados de digestibilidade do tratamento CONT não diferiram dos demais tratamentos. O escore de condição corporal médio foi maior para o tratamento OE em comparação com os demais, porém os aditivos testados não afetaram as concentrações sanguíneas de AGNE e de glicose. Os dados de produção e de composição do leite não foram afetados pelos aditivos testados, assim como os dados de concentração de energia das dietas, consumo de energia, secreção de energia no leite e eficiência de conversão da energia consumida em energia láctea. No experimento 2, a suplementação com OE aumentou a concentração molar de AGV totais e a de acetato em comparação com os tratamentos CONT e AMC, com valores intermediários e não diferentes para o tratamento OE+AMC. Houve aumento do pH ruminal no tratamento AMC em comparação com o tratamento OE. A inclusão de óleos essenciais e ou algas marinhas não alterou a resposta produtiva de vacas leiteiras, apesar do aumento na concentração de AGV e de pH ruminal respectivamente. / Essential oils (OE) and calcareous marine algae (AMC) are being used in ruminants diets. The AMC has been added to diets with the purpose of regulating the ruminal pH while the OE, due to their antimicrobial properties, had been tested as an alternative to the antibiotic additives used in animal production. The objectives of the current study were to evaluate the effects of OE and AMC as well as their interaction on performance and ruminal environment of lactating dairy cows. Two experiments with 32 cows were developed. The animals were in a rotational grazing system supplemented with 6 kg per cow of concentrate feed. Experiment 1 was designed to evaluate performance whereas experiment 2 for ruminal metabolism. During both experiments, cows were assigned to the followings treatments: a) control (CONT); b) blend of essential oils (OE); calcareous marine algae (AMC); d) AMC+OE. In experiment 1, the registered variables were intake, yield and milk composition, live weight, body condition score and blood parameters (glucose and non-esterified fatty acids, [NEFA]). In experiment 2 the same 32 lactating cows were used to evaluate ruminal parameters. The statistical designs used were: replicated Latin square (experiment1) and randomized complete block design (experiment 2). In experiment 1, grass and total DM and OM intakes were increased in AMC compared to OE and OE+AMC. The intakes observed for CONT did not differ from the other treatments. Digestibility of DM and OM were higher for OE and OE+AMC compared to AMC. Digestibility of CONT did not differ from other treatments. The average BCS was higher for OE, however the tested additives did not affect blood concentration of NEFA and glucose. Milk yield and composition were not affected by additives inclusion as well as energy concentration in diets, energy intake, secreted energy in milk and energy conversion efficiency. In experiment 2, OE increased molar concentration of acetate and total VFA when compared to CONT and AMC, but not differed from OE+AMC. The AMC increased ruminal pH when compared to OE. The inclusion of essential oils and/or calcareous marine algae did not alter the productive response of lactating dairy cows, even though there was an increase in VFA concentration and ruminal pH.

As algas marinhas calcárias (AMC) e os óleos essenciais vêm sendo utilizados como aditivos em dietas para ruminantes. As AMC têm sido adicionadas às dietas com o objetivo de modularem o pH ruminal, enquanto os óleos essenciais, através de sua ação antimicrobiana, têm sido testados como alternativa aos aditivos antibióticos na produção animal. Os objetivos do presente estudo foram avaliar os efeitos de óleos essenciais e de algas marinhas calcárias (AMC), bem como a combinação de ambos, sobre desempenho e ambiente ruminal de vacas leiteiras em lactação. Foram realizados 2 experimentos com 32 vacas leiteiras sob sistema de pastejo rotativo com suplementação diária de 6 kg de alimento concentrado por vaca: o experimento 1 foi de desempenho e o experimento 2 de metabolismo ruminal. Em ambos os experimentos as vacas foram submetidas aos seguintes tratamentos: a) controle (CONT); b) óleos essenciais (OE); c) algas marinhas calcárias (AMC); d) AMC + OE. No experimento 1, as variáveis registradas foram consumo, produção e composição do leite, ganho de peso, condição corporal e parâmetros sanguíneos (glicose e ácidos graxos não esterificados [AGNE]). No experimento 2 foram utilizadas as mesmas 32 vacas em lactação para avaliação dos parâmetros ruminais. Os delineamentos utilizados foram: em quadrados latinos replicados (experimento 1) e em blocos inteiramente casualizados (experimento 2). No experimento 1 o CMS de pasto e os CMS e CMO totais foram maiores para o tratamento AMC em comparação com os tratamentos OE e OE+AMC. Os dados de consumo do tratamento CONT foram não diferiram dos demais tratamentos. As digestibilidades da MS e da MO foram maiores para os tratamentos OE e OE+AMC em comparação com o tratamento AMC. Os dados de digestibilidade do tratamento CONT não diferiram dos demais tratamentos. O escore de condição corporal médio foi maior para o tratamento OE em comparação com os demais, porém os aditivos testados não afetaram as concentrações sanguíneas de AGNE e de glicose. Os dados de produção e de composição do leite não foram afetados pelos aditivos testados, assim como os dados de concentração de energia das dietas, consumo de energia, secreção de energia no leite e eficiência de conversão da energia consumida em energia láctea. No experimento 2, a suplementação com OE aumentou a concentração molar de AGV totais e a de acetato em comparação com os tratamentos CONT e AMC, com valores intermediários e não diferentes para o tratamento OE+AMC. Houve aumento do pH ruminal no tratamento AMC em comparação com o tratamento OE. A inclusão de óleos essenciais e ou algas marinhas não alterou a resposta produtiva de vacas leiteiras, apesar do aumento na concentração de AGV e de pH ruminal respectivamente. / Essential oils (OE) and calcareous marine algae (AMC) are being used in ruminants diets. The AMC has been added to diets with the purpose of regulating the ruminal pH while the OE, due to their antimicrobial properties, had been tested as an alternative to the antibiotic additives used in animal production. The objectives of the current study were to evaluate the effects of OE and AMC as well as their interaction on performance and ruminal environment of lactating dairy cows. Two experiments with 32 cows were developed. The animals were in a rotational grazing system supplemented with 6 kg per cow of concentrate feed. Experiment 1 was designed to evaluate performance whereas experiment 2 for ruminal metabolism. During both experiments, cows were assigned to the followings treatments: a) control (CONT); b) blend of essential oils (OE); calcareous marine algae (AMC); d) AMC+OE. In experiment 1, the registered variables were intake, yield and milk composition, live weight, body condition score and blood parameters (glucose and non-esterified fatty acids, [NEFA]). In experiment 2 the same 32 lactating cows were used to evaluate ruminal parameters. The statistical designs used were: replicated Latin square (experiment1) and randomized complete block design (experiment 2). In experiment 1, grass and total DM and OM intakes were increased in AMC compared to OE and OE+AMC. The intakes observed for CONT did not differ from the other treatments. Digestibility of DM and OM were higher for OE and OE+AMC compared to AMC. Digestibility of CONT did not differ from other treatments. The average BCS was higher for OE, however the tested additives did not affect blood concentration of NEFA and glucose. Milk yield and composition were not affected by additives inclusion as well as energy concentration in diets, energy intake, secreted energy in milk and energy conversion efficiency. In experiment 2, OE increased molar concentration of acetate and total VFA when compared to CONT and AMC, but not differed from OE+AMC. The AMC increased ruminal pH when compared to OE. The inclusion of essential oils and/or calcareous marine algae did not alter the productive response of lactating dairy cows, even though there was an increase in VFA concentration and ruminal pH.

Healthy food store availability is by no means equitable, that is supermarkets and supercenters are not located nearby for certain populations. Shopping at healthy food stores is important, as dietary intake is associated with adverse health outcomes, which disproportionally affects racial and ethnic minorities. Yet rural areas and disadvantaged neighborhoods—low income or predominantly racial/ethnic minority compositions—have few healthy food store options available near home. Thus residents must use more resources to access them or make do with what is available close by. However, little is known about the characteristics associated with shopping at healthy food stores or shopping near home. Thus the purpose of this study was to examine predictors of shopping at healthy food stores and shopping within increasing distances from home. This study used data from the USDA’s National Household Food Acquisition and Purchase Survey (FoodAPS) which asked about household food purchasing behaviors. The FoodAPS data set was used to conduct a secondary data analysis of US households (N = 4,826) that was a nationally representative sample. A series of multilevel logistic regression models were conducted to examine the four research questions guiding this study. The four questions examined predictors of: (1) shopping at a healthy food store, (2) shopping at a healthy food store among rural and suburban respondents, (3) shopping within increasing distances from home, and (4) shopping within increasing distances from home among healthy food store shoppers. Results indicated that Hispanic/Latino and other racial/ethnic minority, the distance of travel to the store, and the number of food stores available within 5.0 miles were negatively associated with shopping at a healthy food store. In addition, among rural and urban/suburban respondents had differing predictors of shopping at a healthy food store. Predictors of shopping within increasing distances from home included car to store and living in rural areas. Respondents who used a car as the transportation to the store were less likely to shop within 2.0 miles of home or less. Not surprisingly, rural respondents were also less likely to shop within 5.0 miles of home or less. Several control variables were significant predictors of shopping within increasing distances from home which were unexpected. Results in some instances were surprising and contradictory to findings from past studies. Thus these results are discussed and are compared and contrasted with past studies. The results of this study have practice implications for social workers. Social work practitioners working with individuals can advocate for improving client access in their communities by improving and introducing programming whose goal is to connect people to food resources. Social workers engaged in policy efforts can work at the local, state, and national levels by working in multidisciplinary groups to improve existing programs and prioritize funding that improves issues of equality. While this study examined predictors among a nationally representative sample, it is important for future research to look at differences specifically among age groups, racial and ethnic minorities, and rural residents.

Graded InGaN buffers were employed to relax the strain arising from the lattice and thermal mismatch in GaN/InGaN epilayers grown on sapphire. An enhanced strain relaxation was observed in GaN grown on a stack of five InGaN layers, each 200 nm thick with the In content increased in each layer, and with an intermediate thin GaN layer, 10 nm thick inserted between the InGaN layers, as compared to the conventional two-step growth of GaN epilayer on sapphire. The function of the intermediate layer is to progressively relax the strain and to annihilate the dislocations that build up in the InGaN layer. If the InGaN layers were graded too rapidly, more dislocations will be generated. This increases the probability of the dislocations getting entangled and thereby impeding the motion of the dislocations to relax the strain in the InGaN layer. The optimum growth conditions of the intermediate layer play a major role in promoting the suppression and filling of the V-pits in the GaN cap layer, and were empirically found to be a thin 10 nm GaN grown at 750 0°C and annealed at 1000 0°C. / Singapore-MIT Alliance (SMA)

Graded InGaN buffers are employed to relax the strain arising from the lattice and thermal mismatches between GaN/InGaN epilayers grown on sapphire. The formation of V-pits in linearly graded InGaN/GaN bulk epilayers is illustrated. The V-pits were sampled using Atomic Force Microscopy and Scanning Electron Microscopy to examine their variation from the theoretical geometry shape. We discovered that the size of the V-pit opening in linearly graded InGaN, with and without GaN cap layer, has a Gaussian distribution. As such, we deduce that the V-pits are produced at different rates, as the growth of the InGaN layer progresses. In Stage I, the V-pits form at a slow rate at the beginning and then accelerate in Stage II when a critical thickness is reached before decelerating in Stage III after arriving at a mean size. It is possible to fill the V-pits by growing a GaN cap layer. It turns out that the filling of the V-pits is more effective at lower growth temperature of the GaN cap layer and the size of the V-pits opening, which is continued in to GaN cap layer, is not dependent on the GaN cap layer thickness. Furthermore, graded InGaN/GaN layers display better strain relaxation as compared to conventionally grown bulk GaN. By employing a specially design configuration, the V-pits can be eliminated from the InGaN epilayer. / Singapore-MIT Alliance (SMA)

This paper presents a model and analysis of a synchronous tandem flow line that produces different part types on unreliable machines. The machines operate according to a static priority rule, operating on the highest priority part whenever possible, and operating on lower priority parts only when unable to produce those with higher priorities. We develop a new decomposition method to analyze the behavior of the manufacturing system by decomposing the long production line into small analytically tractable components. As a first step in modeling a production line with more than one part type, we restrict ourselves to the case where there are two part types. Detailed modeling and derivations are presented with a small two-part-type production line that consists of two processing machines and two demand machines. Then, a generalized longer flow line is analyzed. Furthermore, estimates for performance measures, such as average buffer levels and production rates, are presented and compared to extensive discrete event simulation. The quantitative behavior of the two-part type processing line under different demand scenarios is also provided. / Singapore-MIT Alliance (SMA)

Multi-ported memories are challenging to implement on FPGAs since the provided block RAMs typically have only two ports. In this dissertation we present a thorough exploration of the design space of FPGA multi-ported memories by evaluating conventional solutions to this problem, and introduce a new design that efficiently combines block RAMs into multi-ported memories with arbitrary numbers of read and write ports and true random access to any memory location, while achieving significantly higher operating frequencies than conventional approaches. For example we build a 256-location, 32-bit, 12-ported (4-write, 8-read) memory that operates at 281 MHz on Altera Stratix III FPGAs while consuming an area equivalent to 3679 ALMs: a 43% speed improvement and 84% area reduction over a pure ALM implemen- tation, and a 61% speed improvement over a pure "multipumped" implementation, although the pure multipumped implementation is 7.2-fold smaller.