21793 research outputs found
Sort by
E. coli Nissle 1917 as a potential chassis for osmolality biosensors in the gut
Get PDFThe human gut is a heterogeneous environment. Diseases like inflammatory bowel disease (IBD) modify the physical properties of the gut, such as osmolality. These changes are thus desirable biomarkers for personalized diagnosis and treatment. Current diagnostic tools are invasive and insufficient to precisely detect changes of the physical environment. Likewise, disease heterogeneity hinders final diagnosis, showing the importance of creating personalized and sensitive diagnostic tools. For these reasons, its necessary to develop clinically relevant technologies that can safely and accurately report on these physical changes across different regions of the human gut. Extensive research on the human microbiome has revealed that microbes are able to sense shifts in the gut’s physical properties, making them strong candidates to report on these novel biomarkers. Furthermore, advances in synthetic biology have allowed the creation of microbial whole-cell biosensors that robustly report disease biomarkers in the human gut. Therefore, this thesis shows the potential of the probiotic strain Escherichia coli Nissle 1917 (EcN) as a chassis for gut osmolality biosensors. Here, RNA-seq and differential gene expression analysis were used to filter and compare genes that strongly and exclusively respond to different osmolality levels relative to general stress conditions. It was found that five promoters met the conditions, nevertheless, there was cross-reactivity within levels of osmolality and with other general stress conditions. Interestingly, some of the selected promoters had not been shown to react to elevated osmolality conditions, hinting at differences between EcN and other E. coli strains. Based on this, further experimentation is necessary to validate the activity of these promoters in the conditions of interest. Taken together, this work provides a starting point for gut osmolality biosensors using the probiotic strain EcN, providing more options for building biosensors of gut biomarkers
Surgical skills modeling in cardiac ablation using deep learning
Get PDFCardiovascular diseases, a leading global cause of death, can be treated using Minimally Invasive Surgery (MIS) for various heart conditions. Cardiac ablation is an example of MIS, treating heart rhythm disorders like atrial fibrillation and the operation outcomes are highly dependent on the surgeon's skills. This procedure utilizes catheters, flexible endovascular devices inserted into the patient's blood vessels through a small incision. Traditionally, novice surgeons' performance is assessed in the Operating Room (OR) through surgical tasks. Unskilled behavior can lead to longer operations and inferior surgical outcomes. However, an alternative approach can be capturing surgeons' maneuvers and using them as input for an AI model to evaluate their skills outside the OR. To this end, two experimental setups were proposed to study the skills modelling for surgical behaviours. The first setup simulates the ablation procedure using a mechanical system with a synthetic heartbeat mechanism that measures contact forces between the catheter's tip and tissue. The second one simulates the cardiac catheterization procedure for the surgeon’s practice and records the user's maneuvers at the same time. The first task involved maintaining the force within a safe range while the tip of the catheter is touching the surface. The second task was passing a catheter’s tip through curves and level-intersection on a transparent blood vessel phantom. To evaluate attendees' demonstrations, it is crucial to extract maneuver models for both expert and novice surgeons. Data from participants, including novices and experts, performing the task using the experimental setups, is compiled. Deep recurrent neural networks are employed to extract the model of skills by solving a binary classification problem, distinguishing between expert and novice maneuvers. The results demonstrate the proposed networks' ability to accurately distinguish between novice and expert surgical skills, achieving an accuracy of over 92%
Des chiens et des hommes: de quelques espaces d’espèces du théâtre contemporain au Québec
Get PDFDe façon générale, le théâtre québécois s’est à peine préoccupé des questions liées au non-humain, et sa critique encore moins. En effet, Stéphanie Nutting a beau écrire, dans un des seuls articles portant sur le sujet, que « [l]’animal foule régulièrement les planches au Québec et ce, depuis longtemps », il n’en demeure pas moins que cet aspect d’une nature à l’œuvre a très peu retenu l’attention des spécialistes qui ont souvent eu tendance à placer l’activité dramatique à la remorque du politique pris au sens le plus restreint.
La présente thèse veut combler cette lacune en amorçant, dans une optique interdisciplinaire, une réflexion sur la place que l’animal occupe dans les pratiques scéniques québécoises récentes, avec comme point focal l’espèce qui apparaît plus que toutes les autres : le chien. Or si l’ubiquité de Canis familiaris se veut remarquable, elle est également fluctuante dans le temps et dans l’espace, souvent problématique, toujours ambigüe. C’est parce que, selon Richard Schechner, elle partage, avec le théâtre, un vocabulaire et d’innombrables points de contact, que l’anthropologie se voit conviée dans cette étude, aussi parce que la fameuse paire conceptuelle nature-culture s’y articule en moment fondateur depuis les travaux de Claude Lévi-Strauss selon qui « [l]e monde animal et le monde végétal ne sont pas utilisés seulement parce qu’ils sont là, mais parce qu’ils proposent à l’homme une méthode de pensée ».
Ici j’analyse une vingtaine de pièces et spectacles qui, depuis la création, en 1987, de l’œuvre éponyme de Jean Marc Dalpé qui semble donner le ton à mon corpus, mettent en scène au moins un chien comme élément central de la représentation. Cela me permet de baliser le théâtre contemporain au Québec en établissant une géographie critique de ce rapport trouble qui constitue l’une des plus vieilles affaires de discipline(s) qui soit. Ultimement, je désire commencer à répondre à la question suivante : Qu’est-ce que l’animal fait au théâtre, au Québec ? Se dégage, de la violence métonymique au cœur des manifestations canines que j’étudie, peut-être moins le reflet immédiat du social à l’époque de leur présentation, qu’une constellation symbolique annonçant une profonde crise des intériorités et des différences.
Mots clés
Théâtre contemporain au Québec ; culture québécoise ; études animales ; chien (représentation) ; anthropologie de la nature.
= = =
In general, Quebec theatre has hardly been concerned with questions related to the non-human, and its critique even less so. In fact, Stéphanie Nutting may well write, in one of the only articles on the subject, that “[t]he animal regularly treads the boards in Quebec and has done so for a long time,” yet the fact remains that this aspect of nature at work has received very little attention from drama specialists who often tended to place theatre in the context of politics in their most restricted sense.
This thesis aims to fill this gap by initiating, from an interdisciplinary perspective, a reflection on the place that the animal occupies in recent Quebec art practices, with a particular focus on the species that appears more often than all others: the dog. However, if the ubiquity of Canis familiaris is remarkable, it nevertheless remains fluctuating in time and space, often problematic, always ambiguous. It is here that anthropology enters the scene, because, according to Richard Schechner, it shares a vocabulary and innumerable points of contact with the theatre itself, also due to the fact that the famous conceptual nature-culture pair was constituted as a founding moment in the work of Claude Lévi-Strauss, according to whom “[t]he animal world and the plant world are not used only because they are there, but because they offer man a method of thought.”
I analyse some twenty plays and shows, which, since the creation of Le chien by Jean Marc Dalpé in 1987 that set the tone, stage at least one dog as a central element of the performance. My thesis therefore allows me to mark out contemporary theatre in Quebec by establishing a critical geography of this troubled relationship that constitutes one of the oldest intermingling of discipline(s) there is. Ultimately, I want to begin to answer the following question: What animals do in/to theatre in Quebec? What emerges from the metonymic violence at the heart of the canine manifestations I study is maybe not the immediate reflection of the social at that time, so much as a symbolic constellation announcing a deep crisis of interiorities and differences.
Key words
Contemporary theatre in Quebec; Quebec culture; animal studies; dog (representation); anthropology of nature
Deep Learning Methods for Estimation of Elasticity and Backscatter Quantitative Ultrasound
Get PDFUltrasound (US) imaging is increasingly attracting the attention of both academic and industrial researchers due to being a real-time and nonionizing imaging modality. It is also less
expensive and more portable compared to other medical imaging techniques. However, the
granular appearance hinders the interpretation of US images, hindering its wider adoption.
This granular appearance (also referred to as speckles) arises from the backscattered echo
from microstructural components smaller than the ultrasound wavelength, which are called
scatterers. While significant effort has been undertaken to reduce the appearance of speckles,
they contain scatterer properties that are highly correlated with the microstructure of the
tissue that can be employed to diagnose different types of disease. There are many properties
that can be extracted from speckles that are clinically valuable, such as the elasticity and
organization of scatterers. Analyzing the motion of scatterers in the presence of an internal
or external force can be used to obtain the elastic properties of the tissue. The technique
is called elastography and has been widely used to characterize the tissue. Estimating the
scatterer organization (scatterer number density and coherent to diffuse scattering power) is
also crucial as it provides information about tissue microstructure and potentially aids in disease diagnosis and treatment monitoring. This thesis proposes several deep learning-based
methods to facilitate and improve the estimation of speckle motion and scatterer properties, potentially simplifying the interpretation of US images. In particular, we propose new
methods for displacement estimation in Chapters 2 to 6 and introduce novel techniques in
Chapters 7 to 11 to quantify scatterers’ number density and organization
When size matters: Effects of Context and Isolation Training Orthographic Learning
No full textWhen learning to read, children are regularly exposed to words with novel symbols and spellings in stories and lists. I investigated the differential effect of self-teaching in and out of context, as well as the moderating effect of stimulus set size, word length, and word regularity, on the formation of orthographic representations. In Study 1, adult participants practiced reading regularised spellings of real words that were written in an artificial orthography across four experiments (N = 114). Participants trained with either a small set of words or with a large set of words. The first dependent variable was word reading accuracy measured during training (over 6 trials) and 3-days later at post-test. The second and third dependent variables were spelling recognition and production also measured 3-days later at post-test. Generalization of learning was also explored. Results indicate that training in context bolstered reading accuracy during and after training. Yet the highest spelling scores were noted following training in isolation. Further, self-teaching a large set of diverse words in isolation increased reading accuracy, closing the gap with context. Overall, self-teaching in context helped establish orthographic representations that supported reading accuracy. Whereas reading in isolation more highly specified orthographic representations, enabling spelling accuracy—especially when training with a large set of words. Study 2 explored whether these effects could be obtained with children. Children read regular and irregular sets of words of varying length written in standard English orthography across two experiments (N = 64). Reading practice took place in both context and isolation and stimulus set size was experimentally manipulated. Children participants were then asked to complete a variety of reading and spelling retention tasks at post-test. Reading in context supported reading accuracy during training and 1 week later. Like adults, children spelled more words correctly from the isolation training condition. The greatest isolation advantage was for exception words. We also noted that when children had fewer opportunities to map orthographic representations onto pronunciations, training in context was more advantageous than training in isolation. This signals the scope and limitations of reading in context and highlights the faciliatory effect of reading amount
On the Gaussian Product Inequality
Get PDFThe long-standing Gaussian product inequality (GPI) conjecture states that E[|X_1|^{y_1} |X_2|^{y_2} ··· |X_n|^{y_n}] ≥ E[|X_1|^{y_1}] E[|X_2|^{y_2}] ··· E[|X_n|^{y_n}] for any centered Gaussian random vector (X_1 , . . . , X_n) and any non-negative real numbers y_j , j = 1, . . . , n. First, we complete the picture of bivariate Gaussian product relations by proving a novel “opposite GPI” when -10: E[|X_1|^{y_1} |X_2|^{y_2}] ≤ E[|X_1|^{y_1}] E[|X_2|^{y_2}]. Next, we investigate the three-dimensional inequality E[X_1^2 X_2^{2m_2} X_n^{2m_3}] ≥ E[X_1^2] E[X_2^{2m_2}] E[X_n^{2m_3}] for any natural numbers m_2, m_3. We show that this inequality is implied by a combinatorial inequality which we verify directly for small values of m_2 and arbitrary m_3. Then, we complete the proof through the discovery of a novel moment ratio inequality which implies this three-dimensional GPI. We then extend these three-dimensional results to the case where the exponents in the GPI can be real numbers rather than simply even integers. Finally, we describe two computational algorithms involving sums-of-squares representations of polynomials that can be used to resolve the GPI conjecture. To exhibit the power of these novel methods, we apply them to prove new four- and five-dimensional GPIs
Transport of Microplastics in Shore Substrates: Roles of Polymer Characteristics and Environmental Processes
Get PDFThe presence of plastic fragments in the environment is a growing global concern. The coast is particularly vulnerable to microplastic (MP) pollution. However, field experiments are less capable of disentangling the complex interplay of various factors. Therefore, this study aims to investigate the transport of MPs in porous media combined with typical coastal processes. Firstly, a weathering experiment was conducted to comprehensively reveal the changes in MPs in the environment. The results indicated that seawater aging mainly affected the physical properties of MPs, increasing its surface pores and hydrophilicity. Ultraviolent (UV) aging significantly increased its hydrophilicity and crystallinity and introduced oxygen-containing functional groups onto MPs.
Then, the detachment of MPs from porous media under various water content conditions combined with flow patterns was studied. For both the wet and dry conditions, the increase in flow rates decreased the detachment of hydrophobic polyethylene (PE) of two sizes and hydrophilic polymethylmethacrylate (PMMA). Transient flows with varied flow rates and ionic strength led to flow peaks and more MP detachment compared to steady flow. Furthermore, substrate drying significantly impeded the detachment of MPs compared to wet conditions irrespective of the flow regimes. The release of MPs decreased pronouncedly with prolonged air drying duration of the column since drying heightens the energy barrier for MPs to detach.
Tide is a typical coastal process that has profound influence on many biological and abiotic processes. In the following study, the effects of tidal cycles on transport of MPs (4−6 μm PE1; 125 μm PE2; and 5−6 μm polytetrafluoroethylene, PFTE) in porous media were systemically investigated. Smaller substrate sizes exhibited higher retention percentages compared to those of larger substrate sizes under different tidal cycles. In terms of the size of MPs, a larger size (same density) was found to result in enhanced retention of MPs in the column. As the number of tidal cycles increased, although the transport of MPs from the substrate to the water phase was enhanced, less hydrophobic MPs was washed out more with the change in water level. The results implied that MPs with size far smaller than the substrate tend to end up in the open ocean.
To expand our understanding of MP mobilization by tidal movement, the influence of dynamic fluctuations of capillary fringe on the transport of MPs was explored. An increase in the cycles of water table fluctuations enhanced the MPs transport from substrate to the water below. More MPs with larger size were retained in substrate compared to the smaller one. The retention percentages of both PE1 and PTFE in column increased with the elevated ionic strength and the decrease of fluctuation velocity. The results highlight that capillary fringe fluctuation can serve as a pathway to relocate MPs to the tidal aquifer.
Finally, a mesoscale tank experiment was conducted to simulate the infiltration and resuspension of MPs in a slope substrate under the influence of repeated tidal forces. The results imply that large, high-density, and less flat particles tend to be distributed in the lower tidal zone and deeper substrate layers. The obtained observation contributes valuable insights into the behavior, transport, and redistribution of MPs in complex environmental systems. The findings enhance our understanding of MP fate and distribution, assisting in the development of strategies for mitigating MP pollution and managing its impact in coastal areas
Early-career Elementary Teachers’ Perceptions of Self-efficacy in Teaching School-aged Children with ADHD
Get PDFTeaching is a stressful and demanding profession, and teachers have reported above-average rates of burnout compared to other professions. One stressor is teaching and managing the behavior challenges of students, including students with ADHD. Early-career teachers are often critical and, at times, inaccurate in their perceived capabilities, which can negatively affect them and lead to lower job satisfaction and burnout. An online workshop for early-career elementary school teachers (n = 5) was implemented to teach them about ADHD, help them reflect on their perceptions of ADHD, as well as provide them with effective teaching strategies. After the workshop, the teachers completed a reflective workbook which addressed the four sources of information processing pertaining to self-efficacy when teaching and managing students with ADHD (Bandura, 1997). The workbook’s goal was to increase their TSE in teaching and managing students with ADHD. An exploratory mixed method design was used. Data was gathered from the participating teachers using demographic surveys, semi-structured interviews, the KADDS, the TSES, and from their reflective responses in the workbooks. The quantitative survey data triangulated the qualitative data and showed a consistent increase in participants’ scores on the scales at post-intervention. Qualitative findings indicated that all the participants had an increased understanding of ADHD, their perceptions of students with ADHD became more positive, and they reported that they applied more teaching strategies as a result of the workshop. Moreover, the participants described feeling more confident in their abilities post-intervention. This research has implications for designing professional development workshops for teachers
Packaged Printed Multilayer Beamforming Microwave Components
Get PDFLow-loss, compact, and high-frequency microwave devices are in high demand to fulfill the currently required communication systems specifications. Thus, the present work is devoted to the design and compactness enhancement of microwave components. Multilayer technology for printed circuits is utilized for maximum size reduction with artificial magnetic conductor (AMC) packaging to create a self-packaged/shielded system.
An electromagnetic band-gap (EBG) cell is presented to miniaturize the size by replacing the mushroom patch with a spiral unit that lowers the stopband center frequency by half compared to the patch in the same cell size. The principle of operation and parametric studies are discussed. Also, methods to enhance the stop bandwidth are discussed.
Microstrip line (MSL) multilayer power dividers with equal power division to ports in two different layers but different phase outputs are designed. A via less power transfer between the layers is realized by an elliptic slot on the common thick ground plane, which transfers the power throughout the layers capacitively. Various slot and matching transformer shapes control the phase difference between the output ports and the input matching bandwidth. AMC packaging is used to suppress radiation losses and leakage. The realized power dividers achieve a phase difference from 0° to 180° ±6° with a matching input level below -15 dB within 21.8% bandwidth at center frequency 29.75 GHz.
Finally, a novel 4 × 4 multilayer Butler matrix (BM) is proposed, reducing the conventional size by more than twofold. The design eliminates crossover couplers, considerably enhancing compactness and isolation, and uses air MSL packaged by an AMC to suppress wave leakage and radiation loss. The design and performance of the building block components are provided. The BM operates from 27 to 31 GHz with a 0.6 ± 1.4 dB insertion loss and a phase imbalance of ± 8°. It achieves isolation better than 14 dB with a good matching level. The presented 4 × 4 BM concept can be extended to N × N BMs. A four-slot linear antenna array is connected to the BM. The measured and simulated radiation characteristics are compared and found to be in good agreement
Zonal Safety and Particular Risk Analysis for Early Aircraft Design using Parametric Geometric Modelling
Get PDFSafety assessment is paramount in aircraft design. For unconventional aircraft or aircraft with novel propulsion or system architectures or technologies, it is critical to investigate safety as early as possible in the design process to eliminate unfeasible aircraft configurations and system architectures. In this context, the Zonal Safety Analysis (ZSA) and the Particular Risk Analysis (PRA) that evaluate the safety aspects from an aircraft configuration and system placement perspective are essential to perform early. These analyses require a three-dimensional (3D) model of the aircraft and systems and substantial manual effort, limiting the ability to perform rapid iterations required to support design space exploration and, eventually, multidisciplinary design optimization. To analyze many aircraft configurations and system architectures, parametric 3D modelling, ZSA, and PRA require automation. This thesis reviews the methodologies for performing the ZSA and PRA from a systems point of view and proposes a novel methodology for semi-automated conceptual-level ZSA and PRA (CZSA and CPRA) implemented using Python and OpenVSP. As part of CZSA, automated aircraft 3D modelling, parametric zone definition, and zone-component interaction analysis methods are developed that are supported by a manually prepared database of safety-driven best practices. The CPRA involves parametric modelling of particular risk threat zones for trajectory-based PRAs and automated detection of system components in these zones. The effectiveness of the proposed approach is demonstrated with case studies for conventional and unconventional aircraft designs and novel system technologies. The presented work is a step towards integrating system safety analysis into multidisciplinary analysis and optimization environments, thus increasing conceptual design maturity and reducing development time