Transition to turbulence in duct flow

The transition of the flow in a duct of square cross-section is studied. Like in the similar case of the pipe flow, the motion is linearly stable for all Reynolds numbers; this flow is thus a good candidate to investigate the 'bypass' path to turbulence. Initially the so-called 'linear optimal perturbation problem' is formulated and solved, yielding optimal disturbances in the form of longitudinal vortices. Such optimals, however, fail to elicit a significant response from the system in the nonlinear regime. Thus, streamwise-inhomogeneous, sub-optimal disturbances are focussed upon; nonlinear quadratic interactions are immediately evoked by such initial perturbations and an unstable streamwise-homogeneous large amplitude mode rapidly emerges. The subsequent evolution of the flow, at a value of the Reynolds number at the edge between fully developed turbulence and relaminarization, shows the alternance of patterns with two pairs of large scale vortices near opposing parallel walls. Such edge states bear a resemblance to optimal disturbance

Reshaping the Vowel System: An Index of Phonetic Innovation in Canadian English

This paper examines two current sound changes in Canadian English (CE): the Canadian Shift (CS) and the fronting of back-upgliding vowels. Among the changes involved in the CS is the retraction of the TRAP vowel from its initial position in the low-front quadrant of the vowel space to a new position in the low-central region. Among the changes affecting the back-upgliding vowels is a forward shift in the nuclear position of the GOOSE vowel, traditionally a back vowel, whose main allophones are now located in the high-front quadrant. Thus, TRAP is shifting backwards and GOOSE is shifting forwards. These changes are demonstrated with an apparent-time analysis of the speech of 60 speakers from two age groups in three cities: Vancouver, Montreal and Halifax. The relative positions of TRAP and GOOSE in F2 space are expressed as an Index of Phonetic Innovation (IPI), calculated as the mean F2 of GOOSE subtracted from the mean F2 of TRAP. Positive IPI values, with TRAP still further forward than GOOSE, reflect comparatively conservative vowel systems, which tend to have a trapezoidal shape, with two low corners: one in the front, at TRAP, and one in the back, at the LOT vowel. Negative IPI values, with GOOSE further forward than TRAP, reflect comparatively innovative vowel systems, which tend to have a triangular shape, with retracted and lowered TRAP as the bottom corner of an inverted triangle, and LOT located on its rear side. Multivariate statistical analysis of a larger sample of 86 younger speakers from every region of Canada finds that both region and speaker sex have significant effects on the IPI. The most innovative vowel systems tend to be found among women in the most urbanized regions of Canada, particularly the metropolitan areas focused on Toronto and Vancouver, while the most conservative vowel systems tend to be found among men in the less urbanized regions, especially the Prairies and Atlantic Canada. These types are illustrated with detailed analyses of individual speakers from Montreal and Toronto

Cured but not well : long term survivorship after allogeneic haematopoietic stem cell transplantation

Improved donor matching and supportive care have reduced short term complications after allogeneic haematopoietic stem cell transplantation (HSCT), leading to a growing number of survivors. However, despite being cured of leukemia many patients struggle to return to a normal life due to persistent chronic graft versus host disease (cGvHD), fatigue and cognitive dysfunction. Failure to develop tolerance to the grafted immune system underlies cGvHD and we thus hypothesized that MSC treatment may be effective when the first lines of treatment has failed. Further, a similar mechanism in the brain may disrupt neural communication and underlie persistent fatigue and cognitive symptoms. Consequently, this thesis aimed to study MSC treatment of cGvHD, as well as central nervous system (CNS) function, neurobiology, and immunology in patients with fatigue after HSCT. In study I, 11 patients that were refractory to or did not tolerate first-line treatment for cGvHD were administered repeated infusions of allogeneic MSC. Responses were seen in six patients according to the National Institutes of Health scale. Responding patients had a pre- treatment immune phenotype with increased naïve lymphocytes and infusion triggered short- term increases in naïve T-cells and regulatory T-cells. Further, CXC-motif Chemokine Ligand 9 and 10 are potential biomarkers of response, as they decreased in responders and increased in non-responders during the study. Study II, III and IV recruited 27 patients in haematological remission with (n=14) or without (n=13) self-reported fatigue confirmed with validated questionnaires, 1-5 years after HSCT. Metabolic, neurological, and psychiatric diseases were excluded. Fatigue associated with worse quality of life and reduced employment. Further, computerized testing focusing on memory and executive function demonstrated cognitive impairments. Subsequent functional near infra-red spectroscopy showed reduced prefrontal cortex activity during cognitive challenges, and impaired responses to a single dose of methylphenidate, compared to the non-fatigued patients. Lumbar punctures were performed and immune activity in the cerebrospinal fluid was assessed by proteomic analyses, mRNA sequencing and flow cytometry. Cognitive dysfunction was associated with reduced factors involved in immune regulation, neurogenesis, and synapse function, supported by mRNA-expression suggestive of reduced cell-cell adhesion and noradrenergic neuron differentiation. Flow cytometry demonstrated increased activated T-cells in patients with fatigue and cognitive dysfunction. In summary, cGvHD is the manifestation of an imbalance between inflammatory and regulatory factors after HSCT, where the stroma plays a major role. MSC treatment can restore this balance by inducing regulatory phenotypes in innate and adaptive immune cells, as demonstrated by the clinical responses seen in study I. We show that dysregulated immune activation after HSCT also occur in the CNS. Deficits in stromal-derived, reparative, and trophic factors in liquor, characterized patients with fatigue and cognitive dysfunction, perhaps by impairing cortical activity. This thesis emphasizes the need to understand the stroma-immune crosstalk, to design targeted therapies for debilitating, currently untreatable inflammatory conditions

PROC REPORT IN STYLE

I would like to demonstrate how you can create colorful PDF files using ODS (Output Delivery System) with different predefined style templates for the layout and color scheme of both tables and graphs. There are a few different ways you can customize your reports in the Report Procedure. Traffic lighting is a very popular technique and can be achieved by changing the font and/or the background colors. I prefer to customize my reports by adding background color to highlight a row, column, and/or cell in a table. I will share my favorite styles and show you how to look at your tables in the different styles available. I will briefly explain how you can create your own style by changing the color scheme of an existing style so that it can be used for all of your reports. I will explain how I used the pieces of code to get the table with a row, a column and individual cells highlighted with several different colors. I will focus on creating PDF files using ODS, but these methods can be used with other output destinations. This paper is for beginner to intermediate level SAS® programmers with experience creating tables with Report procedure