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<p>Salmonids, such as rainbow trout, form social hierarchies, consisting of dominant and subordinate individuals, when in groups in environments with limiting resources, such as space or food. There were two main objectives for this thesis: to investigate the physiological consequences of being in a social hierarchy as well as to investigate whether grouped social status or individual behaviour most accurately recorded physiological data for a hierarchy and secondly, to investigate the behavioural and physiological changes of groups of rainbow trout exposed to ammonia concentrations which are above chronic protected guidelines.</p> <p>To create social hierarchies, groups of four fish were fed by a new method using a darkened feeding container, twice daily (morning and evening) for eight days. Each morning feeding was videotaped in order to record aggressive behaviour. Each aggressive act was scored, allowing for fish to be assigned a social status. For ammonia exposures, groups of fish were exposed to either 700, 1200 and 1500 µM total ammonia (or 2.97, 5.10, 6.37 µM NH3, respectively) 24 hours before first feeding and these concentrations were maintained throughout the experiment. On day 5 and day 10, physiological parameters were taken in fish fasted for 24-h in control and 700 µM total ammonia exposed hierarchies.</p> <p>Social hierarchies were created in all ammonia-free and 700 µM total ammonia groups, with no hierarchies formed in 1200 and 1500 µM total ammonia groups. In M.Sc. Thesis – Josias (Si) Grobler McMaster University – Department of Biology iv ammonia-free hierarchies, one fish would become dominant, while the three subordinate individuals would each assume a stable social rank and display similar physiology which was different from the dominant fish.</p> <p>Fish from the 700 µM total ammonia group showed reductions in various physiological parameters during period 1, however, these fish displayed similar values as what was reported in ammonia-free hierarchies during period 2. This suggests biochemical or physiological changes occurring in these fish in order to acclimate to the high ammonia environment</p> / Master of Science (MSc)

Studies attempting to increase working memory (WM) capacity show promise in enhancing related cognitive functions (see Morrison & Chein, 2011 for a recent review), but have also raised criticism in the broader scientific community given the scattered findings produced by these studies (Morrison & Chein, 2011; Shipstead, Redick, & Engle, 2010, 2012). Non-invasive brain stimulation, in particular transcranial direct current stimulation, has been shown to enhance WM performance in a single session (Fregni, et al., 2005) as well as learning over time in other cognitive domains (Iuculano & Cohen Kadosh, 2013; Reis, et al., 2009). However, the extent to which tDCS might enhance learning on a WM training regime, and the extent to which learning gains might transfer outside of the training task remain unknown. To this end, participants engaged in an adaptive WM training task (previously utilized in Chein & Morrison, 2010; Richmond, Morrison, Chein, & Olson, 2011) for 10 sessions over two weeks, concurrent with either active or sham stimulation of dorsolateral prefrontal cortex. Before and after training, a battery of tests tapping domains known to relate to WM abilities was administered. Results show that tDCS reliably enhanced learning on the training task, particularly in the verbal domain. Furthermore, tDCS was shown to enhance transfer to other untrained WM tasks. These results lend support to the idea that tDCS might bolster training and transfer gains in populations with compromised WM abilities. / Psychology

Articular cartilage has limited intrinsic healing capacity due to its dense and avascular structure. Clinical approaches have been developed to address the limitations associated with the poor ability of articular cartilage to regenerate. Current clinically approved techniques, however, can result in repair tissue that lacks appropriate hyaline cartilage biochemical and biomechanical properties, which lead to uncertain long-term clinical outcomes. Using tissue engineering strategies and a range of scaffolding materials, cell types, growth factors, culture conditions, and culture times, engineered tissues have been produced with compositional and biomechanical properties that approximate that of native tissue. In these studies, a considerable number of samples are typically sacrificed to evaluate compositional and mechanical properties, such as the amount of deposited collagen and sulfated glycosaminoglycan (sGAG) in the constructs. The number of sacrificed samples, as well as the amount of time and resources spent to evaluate the sacrificed samples using current gold standards, motivates an alternative method for evaluation of compositional properties. Vibrational spectroscopy, including infrared, has been considered as an alternative technique for assessment of tissues over the last 15-20 years. Infrared spectroscopy is based on absorbance of infrared light by tissue functional groups at specific vibrational frequencies, and thus, no external contrast is required. Vibrational spectroscopy is typically performed in two frequency regions, the mid infrared region (750-4000 cm-1), where penetration depth is limited to approximately 10 microns, and the near infrared (NIR) region (4000-12000 cm-1). In the NIR region, penetration of light is on the order of millimeters or centimeters, which makes it ideal for obtaining data through the full depth of engineered constructs. Here we employ NIR spectroscopy to nondestructively monitor the development of tissue-engineered constructs over culture period. / Bioengineering

付記する学位プログラム名: 霊長類学・ワイルドライフサイエンス・リーディング大学院 / 京都大学 / 新制・課程博士 / 博士(理学) / 甲第24467号 / 理博第4966号 / 新制||理||1709(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)准教授 Huffman Michael Alan, 教授 古市 剛史, 教授 今井 啓雄 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DFAM

A novel acoustic sensor has been developed, capable of remotely monitoring the free surface ‘fingerprint’ of shallow flows. Temporal and spatial properties of this pattern are shown to contain information regarding the nature of the flow itself. The remote measurement can thereby be used to infer the bulk flow properties such as depth, velocity, and the hydraulic roughness of the pipe. The instrument is non-invasive and is also low cost, low maintenance, and low power. Such a device will allow for widespread monitoring of flow conditions in drainage networks, enabling pro-active maintenance and reliable real-time control.

Background: In intensive care, mechanical ventilation is a common treatment for critically ill patients. Patients are often treated with both sedative and pain-relieving drugs, which together with invasive mechanical ventilation puts the patient in a particularly vulnerable situation as the ability to verbally communicate is limited. This makes it difficult for both the intensive care nurse and relatives to know what the patient remembers and how they have experienced their time with mechanical ventilation. Aim: To review and synthesize qualitative studies that have explored adult patients' memories of their time with invasive mechanical ventilation in an intensive care unit. Method: A structured literature review with qualitative design. Structured searches were conducted in the databases PubMed, CINAHL and Psychinfo, which resulted in 18 articles of qualitative design and mixed method and published between the years 2009-2024. Included articles are quality reviewed according to Caldwell's review template and the results of the articles are analyzed using an inductive thematic analysis. Results: The results present two main themes with associated subthemes. The main theme In the shadow of suffering had associated subthemes Pain and discomfort and An unreal existence. The main theme Abandoned in a strange environment had associated subthemes Voiceless in a world of sound and Seeing yourself fragile through the eyes of others. Conclusion: Patients' memories of the time in the intensive care unit with invasive mechanical ventilation vary, but overall the period is described as heavy and psychologically stressful. Communication and information from relatives and healthcare professionals is crucial for patients' well-being, and intensivecare nurses have an important role in supporting and including relatives in care. A professional approach to nursing care, regardless of whether the patient is sedated or awake, is essential for as pleasant an experience as possible.

Biological invasions have been observed throughout the world for centuries, often with major consequences to biodiversity and food security. Tying invasion to species identity and associated traits has led to numerous hypotheses on why, and where, some species are invasive. In recent decades, attention to intraspecific variation among invaders has produced questions about their adaptation to climate, land use, and environmental change. I examined the intraspecific variation of invasive Johnsongrass's (Sorghum halepense (L.) Pers.) seedling stress response, propagule cold tolerance, and large-scale niche dynamics for correlation with populations' climatic and ecotypic (i.e., agricultural vs. non-agricultural) origin. Overall, I found a greater number of home climate effects than ecotypic effects on various traits. Non-agricultural seed from cold climates and agricultural seed from warm climates germinated more and faster, while non-agricultural seedlings showed uniform chlorophyll production regardless of home soil carbon origin, unlike their agricultural counterparts. Neither seedling stress response nor propagule cold tolerance interacted with ecotype identity; however, drought stress varied with population origins' aridity and soil fertility, and seed from warm/humid and cold/dry climates was most germinable. Comparison of seed and rhizome cold tolerance also suggested that the latter is a conserved trait that may be limiting S. halepense poleward range expansion. This physiological limit, an unchanged cold temperature niche boundary between continents and ecotypes, and a narrowed niche following transition to non-agricultural lands all imply low likelihood of spread based on climatic niche shift. Instead, evidence points to range expansion driven primarily by climate change and highlights agriculture's role in facilitating invasibility. This tandem approach to climate and land use as drivers of intraspecific variation is transferable to other taxa and can help refine our conception of and response to invasion in the Anthropocene. / Doctor of Philosophy / Exotic invasive species are a global problem, threatening biodiversity and biosecurity now and in the future. In the last several decades, ecologists have studied many individual invaders and their traits to understand what drives their spread. More recently, abundant differences in traits between populations within an invasive species have raised questions about humans' role in facilitating invasion through climate change, land use, and other disturbances. I studied the invasive Johnsongrass's (Sorghum halepense (L.) Pers.) response to drought, nutrient limitation, and freezing to detect differences between populations based on their climate and ecotype (agricultural vs. non-agricultural) origin. I also tracked differences in the climates the species occupied across the globe and North America and projected its future distribution under climate change. Overall, I found a greater number of home climate effects than ecotypic effects on various traits. Non-agricultural seed from cold climates and agricultural seed from warm climates germinated the most, while non-agricultural seedlings performed consistently regardless of soil carbon origin, unlike their agricultural counterparts. In addition, drought stress varied with population origins' rainfall and soil fertility, and seed germination favored warm/humid and cold/dry origin. Rhizome (underground stem) cold tolerance appears to be a trait that limits S. halepense poleward range expansion. Along with no change in the coldest climates occupied worldwide and no spread to new climates with transition to non-agricultural lands, this implies that Johnsongrass is unlikely to expand its range without external forces. Instead future range expansion will likely be driven by climate change. This coupled approach to climate and land use affecting invasion is transferable to other species and can help refine both our concepts and response strategies.