The Importance of Mapping to the Next Generation Retinal Prosthesis

Evolutionarily, human beings have come to rely on vision more than any other sense, and with the prevalence of visual-oriented stimuli and the necessity of computers and visual media in everyday activities, this can be problematic. Therefore, the development of an accurate and fast retinal prosthesis to restore the lost portions of the visual field for those with specific types of vision loss is vital, but current methodologies are extremely limited in scope. All current models use a spatio-temporal filter (ST), which uses a difference of Gaussian (DOG) to mimic the inner layers of the retina and a noisy leak and fire integrate (NLIF) unit to simulate the optical ganglion. None of these processes show how these filters are mapped to each other, and therefore simulate the interaction of cells with each other in the retina. The mapping is key to having a fast and efficient filtering method; one that will allow for higher-resolution images with significantly less hardware, and therefore power requirements. The focus of this thesis was streamlining this process: the first major portion involved was applying a pipelining system to the 3D-ADoG, which showed some significant improvement over the design by Eckmiller. The major contribution was the mapping process: three mapping schemes were tried, and there was a significant difference found between them. While none of the models met the timing requirements, the ratios for speedups seen between the methods was significant. Evolutionarily, human beings have come to rely on vision more than any other sense, and with the prevalence of visual-oriented stimuli and the necessity of computers and visual media in everyday activities, this can be problematic. Therefore, the development of an accurate and fast retinal prosthesis to restore the lost portions of the visual field for those with specific types of vision loss is vital, but current methodologies are extremely limited in scope. All current models use a spatio-temporal filter (ST), which uses a difference of Gaussian (DOG) to mimic the inner layers of the retina and a noisy leak and fire integrate (NLIF) unit to simulate the optical ganglion. None of these processes show how these filters are mapped to each other, and therefore simulate the interaction of cells with each other in the retina. The mapping is key to having a fast and efficient filtering method; one that will allow for higher-resolution images with significantly less hardware, and therefore power requirements. The focus of this thesis was streamlining this process: the first major portion involved was applying a pipelining system to the 3D-ADoG, which showed some significant improvement over the design by Eckmiller. The major contribution was the mapping process: three mapping schemes were tried, and there was a significant difference found between them. While none of the models met the timing requirements, the ratios for speedups seen between the methods was significant. Despite the speedups and potential power savings, none of the other papers made specific mention of using any mapping schemes, nor how they improve both the speed and quality of the output images. The closest reference: a very vague reference to the amount of overlap as a tunable feature. Nevertheless, this is a key feature to developing the next generation prosthesis, and the manner in which the output from the ST filter bank is mapped seems to have a significant effect on speed, quality, and efficiency of the entire system as a whole

Investigating Colonization of the Healthy Adult Gastrointestinal Tract by Fungi

A wide diversity of fungi have been detected in the human gastrointestinal (GI) tract with the potential to provide or influence important functions. However, many of the fungi most commonly detected in stool samples are also present in food or the oral cavity. Therefore, to recognize which gut fungi are likely to have a sustained influence on human health, there is a need to separate transient members of the GI tract from true colonizers. To identify colonizing fungi, the eukaryotic rRNA operon’s second internal transcribed spacer (ITS2) was sequenced from the stool, saliva, and food of healthy adults following consumption of different controlled diets. Unlike most bacterial 16S rRNA genes, the only fungal ITS2 operational taxonomic units (OTUs) detected in stool DNA across multiple diets were also present in saliva and/or food. Additional analyses, including culture-based approaches and sequencing of the 18S rRNA gene, ITS2 cDNA, and DNA extracted using alternative methods, failed to detect additional fungi. Two abundant fungi, Saccharomyces cerevisiae and Candida albicans, were examined further in healthy volunteers. Saccharomyces became undetectable in stool when a S. cerevisiae-free diet was consumed, and the levels of C. albicans in stool were dramatically reduced by more frequent cleaning of teeth. Extremely low fungal abundance, the inability of fungi to grow under conditions mimicking the distal gut, and evidence from analysis of other public datasets further support the hypothesis that fungi do not routinely colonize the GI tracts of healthy adults

The gut mycobiome of the Human Microbiome Project healthy cohort

Background: Most studies describing the human gut microbiome in healthy and diseased states have emphasized the bacterial component, but the fungal microbiome (i.e., the mycobiome) is beginning to gain recognition as a fundamental part of our microbiome. To date, human gut mycobiome studies have primarily been disease centric or in small cohorts of healthy individuals. To contribute to existing knowledge of the human mycobiome, we investigated the gut mycobiome of the Human Microbiome Project (HMP) cohort by sequencing the Internal Transcribed Spacer 2 (ITS2) region as well as the 18S rRNA gene. Results: Three hundred seventeen HMP stool samples were analyzed by ITS2 sequencing. Fecal fungal diversity was significantly lower in comparison to bacterial diversity. Yeast dominated the samples, comprising eight of the top 15 most abundant genera. Specifically, fungal communities were characterized by a high prevalence of Saccharomyces, Malassezia, and Candida, with S. cerevisiae, M. restricta, and C. albicans operational taxonomic units (OTUs) present in 96. 8, 88.3, and 80.8% of samples, respectively. There was a high degree of inter- and intra-volunteer variability in fungal communities. However, S. cerevisiae, M. restricta, and C. albicans OTUs were found in 92.2, 78.3, and 63.6% of volunteers, respectively, in all samples donated over an approximately 1-year period. Metagenomic and 18S rRNA gene sequencing data agreed with ITS2 results; however, ITS2 sequencing provided greater resolution of the relatively low abundance mycobiome constituents. Conclusions: Compared to bacterial communities, the human gut mycobiome is low in diversity and dominated by yeast including Saccharomyces, Malassezia, and Candida. Both inter- and intra-volunteer variability in the HMP cohort were high, revealing that unlike bacterial communities, an individual’s mycobiome is no more similar to itself over time than to another person’s. Nonetheless, several fungal species persisted across a majority of samples, evidence that a core gut mycobiome may exist. ITS2 sequencing data provided greater resolution of the mycobiome membership compared to metagenomic and 18S rRNA gene sequencing data, suggesting that it is a more sensitive method for studying the mycobiome of stool samples

Concept development of tank mounts for the integration of liquid hydrogen Tanks into aircraft structure supported by analytical and numerical means

The integration of hydrogen storage into the aircraft structure is vital to realize future clean aviation with hydrogen as energy carrier. For aircraft with ranges above regional that make up about 94% of CO2 emissions in the passenger transportation sector, large liquid hydrogen tanks are required that will be non-integral in the first developments. In aviation, tanks with cryogenic liquid hydrogen cooled down to -253 °C are used to achieve the highest possible volumetric efficiency. These non-integral tanks dictate the need of structural attachments between tank and fuselage. This master’s thesis links the mechanical and thermal challenges regarding load and heat transfer between the fuselage and the insulated tank. With regards to existing concepts from different applications and the derived boundary conditions on an aircraft, requirements for a tank suspension system are created. Based on these requirements, four concepts are developed and preliminarily sized. A metallic concept with a cylindrical mount shape was found to be most suitable to fulfill the determined requirements. The glass fiber composite version provides about three times higher thermal resistance. It was concluded, though, that the thermal loads do not present as big as an issue as expected. During standard operation a small temperature delta of merely 2 K was determined between the outer tank wall and the ambient temperature. The thermal resistance becomes more prominent in case of a vacuum break and a loss of insulation. With the chosen tank mounts, a fuselage temperature of 211 K during vacuum break at flight altitude is computed. As no limiting factor regarding a minimal fuselage temperature was found, this is seen as not critical. The challenge of the mechanical loads next to the general load definition is found to be the load inducement into the thin outer tank walls. Using reinforced joint areas of the outer vessel components to transfer the loads between wall and mount is found to be most suitable. As the cylindrical tank mounts provide a high thermal resistance geometrically, numerous mounts can be placed circumferentially around the tank to enhance the load distribution among the tank wall. A substantial challenge of the tank integration of non-integral tanks is the removability and accessibility for maintenance and tank exchange. Even though, the tank must only be exchanged three to four times in the aircraft’s lifespan, constructive measures for fuselage break points are to be implemented. A vertical exchange of the tanks is preferred regarding the access to the tank mounts. One suspension system has been developed with the focus on easy assembly and exchangeability, next to the mechanical and thermal requirements. The form-fitting mount shows a high volumetric efficiency and can be fixed through minimal installation patches in the fuselage skin but provides insufficient thermal resistance in a metallic configuration. Further research is required concerning the thermal deformation of the tank and the load transfer to the airframe. Here, replacing two conventional frames per tank with reinforced bulkheads are recommended

TOW еко-мігранти в контексті міжнародного права біженців та прав людини: оцінка проблем правового захисту мігрантів

The concept and the rights of environmental refugee have attracted national, international governance and scholars’ attention. I have tried to analyses through descriptive and explanatory approach the current trend of environmental refugees’ legal protection and its limitation and achievement. Thus, the objective of this research work is first to review legal scholars’ work, relating to environmental refugees to show the current trend, relating to environmental refugees protection. Second, to analyse the existing legal framework to show, whether it adequately has governed the issue of environmental refugees’ rights and identify the gap. Third, it explains the ways forward. The international refugee law (the 1951 refugee convention and the 1969 OAU refugee convention), the international environmental law, international law on Stateless persons, the international human right law and the system of temporary protected status. Environmental refugees could be referred otherwise as environmental migrants, environmentally displaced persons, climate refugees, climate change refugees, environmental refugees and ecological refugees, thus it implies the same thing in this context. The legal concepts are making that definition, such as well-founded fear, persecution, crossing international border, exclusion from refugee status (undeserving cases), and cessation of refugee status. The UN High Commissioner for Refugees state that 36 million people were displaced by natural disasters in 2009, and about 20 million of those were forced to move for climate change-related issues. According to other estimates, there could be as many as 150 million by 2050. In accordance with the estimates of UN Environment Programme, by 2060 there could be 50 million environmental refugees in Africa alone.Понятие эко-беженцы и их права привлекали внимание национальных и международных правительств, а также учёных. Я попытался проанализироать, используя описательный и объяснительный подход, актуальность правовой защиты эко-беженцев, её достижения и недостатки. Таким образом, цель данной работы, прежде всего, рассмотреть работы учёных в области права, касающиеся эко-беженцев, и показать настоящее положение дел в сфере эащиты эко-беженцев. Во-вторых, проанализировать существующие правовые рамки, показать, насколько адекватно они отражают права эко-беженцев, а также найти пробелы. В-третьих, выяснить пути дальнейшего разрешения проблемы: Международное право беженцев (конвенция о беженцах 1951 года и ОАЕ конвенция о беженцах 1969 года), международное экологическое право, международное право граждан, лищённых государства, международное право человека и система временного статуса защиты. Эко-беженцы могут быть также обозначены как эко-мигранты, экологически перемещённые лица, климатические беженцы, жертвы смены климата, таким образом, эти обозначения равноценны в данном контексте. Даный правовой концепт предусматривает обоснованный страх, преследование, пересечение границы между государствами, исключение из статуса беженца (несоответствующие случаи) и отмена статуса беженца. Верховный комиссар ООН по правам беженцев утверждает, что 36 миллионов человек были перемещены по причине природных катастроф в 2009, и около 20 миллионов были вынуждены мигрировать по причине климатических изменений. Согласно другим оценкам, к 2050 году их может быть 150 миллионов. Согласно оценкам Экологической программы ООН, к 2060 в одной только Африке может быть 50 миллионов эко-беженцевПоняття еко-біженці та їхні права привертали увагу націонаних та міжнародних урядів, а також вчених. Я намагався проаналізувати за допомогою описового та пояснювального підходів актуальність правового захисту еко-біженців, її досягнення та недоліки. Таким чином, мета цієї роботи по-перше, розглянути роботи вчених в сфері права, що стосуються еко-біженців, показати справжній стан справ в сфері захисту еко-біженців. По-друге, проаналізувати існуючі правові рамки, показати наскільки адекватно вони відображають права еко-біженців, а також знайти пробіли. По-третє, прояснити шляхи подальшого розв”язання проблеми: Міжнародне право біженців (конвенція про біженців 1951 року та конвенція ОАЄ про біженців 1969 року), міжнародне екологічне право, міжнародне право громадян, позбавлених держави, міжнародне право людини та система тимчасового статуса захисту. Еко-біженці можуть також бути позначені як еко-мігранти, екологічно переміщені особи, кліматичні біженці, жертви зміни клімату, таким чином, ці позначення рівноцінні в данному контексті. Цей правовий концепт передбачає обґрунтований страх, переслідування, перетин державного кордону, виключення зі статусу біженця (невідповідні кейси) та відміна статуса біженця. Верховний комісар ООН по правам біженців стверджує, що 36 мільйонів людей були переміщені через природні катастрофи в 2009 році та майже 20 мільйонів були вимушені мігрувати через кліматичні зміни. Згідно інших оцінок, до 2050 року їх може бути 150 мільйонів. Згідно оцінок Екологічної Програми ООН, до 2060 року в одній лише Африці може бути мільйонів еко-біженці

Investigating Colonization of the Healthy Adult Gastrointestinal Tract by Fungi

A wide diversity of fungi have been detected in the human gastrointestinal (GI) tract with the potential to provide or influence important functions. However, many of the fungi most commonly detected in stool samples are also present in food or the oral cavity. Therefore, to recognize which gut fungi are likely to have a sustained influence on human health, there is a need to separate transient members of the GI tract from true colonizers. To identify colonizing fungi, the eukaryotic rRNA operon’s second internal transcribed spacer (ITS2) was sequenced from the stool, saliva, and food of healthy adults following consumption of different controlled diets. Unlike most bacterial 16S rRNA genes, the only fungal ITS2 operational taxonomic units (OTUs) detected in stool DNA across multiple diets were also present in saliva and/or food. Additional analyses, including culture-based approaches and sequencing of the 18S rRNA gene, ITS2 cDNA, and DNA extracted using alternative methods, failed to detect additional fungi. Two abundant fungi, Saccharomyces cerevisiae and Candida albicans, were examined further in healthy volunteers. Saccharomyces became undetectable in stool when a S. cerevisiae-free diet was consumed, and the levels of C. albicans in stool were dramatically reduced by more frequent cleaning of teeth. Extremely low fungal abundance, the inability of fungi to grow under conditions mimicking the distal gut, and evidence from analysis of other public datasets further support the hypothesis that fungi do not routinely colonize the GI tracts of healthy adults

The gut mycobiome of the Human Microbiome Project healthy cohort

Background: Most studies describing the human gut microbiome in healthy and diseased states have emphasized the bacterial component, but the fungal microbiome (i.e., the mycobiome) is beginning to gain recognition as a fundamental part of our microbiome. To date, human gut mycobiome studies have primarily been disease centric or in small cohorts of healthy individuals. To contribute to existing knowledge of the human mycobiome, we investigated the gut mycobiome of the Human Microbiome Project (HMP) cohort by sequencing the Internal Transcribed Spacer 2 (ITS2) region as well as the 18S rRNA gene. Results: Three hundred seventeen HMP stool samples were analyzed by ITS2 sequencing. Fecal fungal diversity was significantly lower in comparison to bacterial diversity. Yeast dominated the samples, comprising eight of the top 15 most abundant genera. Specifically, fungal communities were characterized by a high prevalence of Saccharomyces, Malassezia, and Candida, with S. cerevisiae, M. restricta, and C. albicans operational taxonomic units (OTUs) present in 96. 8, 88.3, and 80.8% of samples, respectively. There was a high degree of inter- and intra-volunteer variability in fungal communities. However, S. cerevisiae, M. restricta, and C. albicans OTUs were found in 92.2, 78.3, and 63.6% of volunteers, respectively, in all samples donated over an approximately 1-year period. Metagenomic and 18S rRNA gene sequencing data agreed with ITS2 results; however, ITS2 sequencing provided greater resolution of the relatively low abundance mycobiome constituents. Conclusions: Compared to bacterial communities, the human gut mycobiome is low in diversity and dominated by yeast including Saccharomyces, Malassezia, and Candida. Both inter- and intra-volunteer variability in the HMP cohort were high, revealing that unlike bacterial communities, an individual’s mycobiome is no more similar to itself over time than to another person’s. Nonetheless, several fungal species persisted across a majority of samples, evidence that a core gut mycobiome may exist. ITS2 sequencing data provided greater resolution of the mycobiome membership compared to metagenomic and 18S rRNA gene sequencing data, suggesting that it is a more sensitive method for studying the mycobiome of stool samples

L'Auto-vélo : automobilisme, cyclisme, athlétisme, yachting, aérostation, escrime, hippisme / dir. Henri Desgranges

23 mars 19041904/03/23 (A5,N1258)