The purpose of the thesis is to gain more insights into the factors of business-to-consumer (B2C) relationships and how they can be used to mitigate negative changes in consumer behaviors during crises. In today's changing landscape, companies are faced with the challenge of understanding and managing consumer behavior in moments when they are hit by unpredictable events in the form of crises, where the importance of B2C relationships can have a significant influence on consumer behavior. The study employs a qualitative research method, utilizing semi-structured interviews with consumers to gain valuable insights into their experiences and perceptions. The study supports and builds on the existing theoretical framework and provides more insights into the subject. The results highlight the importance of establishing and maintaining relationships with consumers during crises, and the significance of trust, commitment, and communication as important factors within these relationships. The paper contributes to companies' ability to maintain consumers during crises. Ultimately, the results of this thesis enable companies and marketers to effectively manage and understand the importance of B2C relationships as well as navigate the complexities of consumer behavior during times of crisis.

Embryonic stem (ES) cells have the ability to maintain pluripotency and self-renewal during in vitro maintenance, which is a key to their clinical applications. ES cells are a model in developmental biology studies due to their potential to differentiate in vitro. Understanding critical pathways of pluripotency, self-renewal, and differentiation during early embryonic development is important for the evaluation of the therapeutic potential of ES cells because of their ability for tumor transformation due to genetic and epigenetic instability acquired during in vitro culture maintenance. Single tandem repeats are sequences of DNA that have been implicated in the deregulation of gene expression in different human conditions. Understanding the origin of repetitive sequence instability and functions in the genome allow characterization of early genomic instability signals in ES cell pluripotency, differentiation, and tumor transformation pathways. The hypothesis of this study was that genetic stability, in repetitive sequences, located near embryonic developmental genes is responsible for pluripotency, self-renewal, differentiation, and chromatin assembly and could be a signal for adaptation, differentiation, or transformation of ES cells in vitro. Our result showed instability in specific repetitive sequences which increased during ES cell passages and embryoid body differentiation in vitro. ES cells displayed significant mean frequencies of genomic instability in repetitive regions that lead to ES cells pluripotency, self-renewal maintenance, or cell lineage specialization. The present study reports potentially biomarkers for identifying accumulation of genomic instability in specific genes that may contributes to adaptation of ES cells and could be the switch that initiates early ES cell lineage commitment in vitro. Determining genetic and epigenetic modifications, including single tandem repeat instability, gene expression changes, and chromatin modifications, is essential for elucidating possible molecular mechanisms of genomic instability and determining novel molecular characterization for diagnostic purposes to ensure ES cell stability and integrity that could potentially lead to use of ES cell derivatives that could then be a safe source needed for regenerative medicine applications

[pt] Neste trabalho é desenvolvida uma metodologia baseada no Método dos Elementos Finitos para estudar o equilíbrio e a estabilidade de placas apoiadas em fundações elásticas. A formulação utilizada para a análise de placas é válida para a análise linear e não-linear de placas isotrópicas ou ortotrópicas, perfeitas ou inicialmente imperfeitas. Esta formulação é baseada nas teorias de placas de Mindlin e von Kármán e na teoria de cascas abatidas proposta por Marguerre. As placas podem estar apoiadas em fundações lineares ou não-lineares, que são modeladas utilizando elementos finitos isoparamétricos. A fundação não-linear contém termos cúbicos e quadráticos, de modo a permitir uma representação mais realista do seu comportamento. Na obtenção dos caminhos não-lineares de equilíbrio das estruturas, diferentes métodos incrementais-iterativos são utilizados. Com o objetivo de considerar o problema de contato unilateral, duas formulações que utilizam técnicas de Programação Matemática são implementadas, sendo uma para a análise linear e outra para a análise não-linear. Além dessas formulações, o problema de contato unilateral pode ser tratado através do uso de um modelo constitutivo de fundação não resistente à tração também implementado neste trabalho. Exemplos de equilíbrio e de estabilidade são apresentados e, quando possível, os resultados são comparados com os existentes na literatura. Através destes exemplos, estuda-se a influência da não-linearidade da placa e da fundação, das imperfeições geométricas iniciais e do tipo de contato (unilateral ou bilateral) na capacidade de carga e estabilidade da placa. Também é discutida a influência do uso de diferentes malhas de elementos finitos nestes resultados, bem como a eficiência computacional das metodologias utilizadas para lidar com o contato unilateral. / [en] In this work, a finite element formulation to study the equilibrium and the stability of plates on elastic foundations is developed. This formulation can be used for linear and nonlinear analyses of isotropic or orthotropic, perfect or initially imperfect plates. It is based on Mindlin`s and von Kármán`s plate theories and on the shallow shell theory proposed by Marguerre.The plates can be on linear or non-linear foundations modeled using isoparametric finite elements. The non-linear foundation contains cubic and quadratic terms to allow a more realistic representation of its behavior. In order to obtain the equilibrium path of the structure, different incremental-iterative methods are employed.Two different strategies are implemented to solve the unilateral contact problem. In the first one, two formulations that use optimization techniques are developed, one for the linear analysis and the other one for non-linear analysis. The second strategy modifies the constitutive relation of the foundation in order to simulate its tensionless behavior.Equilibrium and stability examples are presented and, whenever possible, the results are compared with the ones found in the literature. In these examples, the influence of the non-linearities of the plate and the foundation, of initial geometric imperfections, and of the type of contact (unilateral or bilateral) on the load capacity and stability of the plate is studied. The influence of different finite element meshes on the results and the computational efficiency of the methodologies used to solve the unilateral contact problem are also discussed. / [es] En este trabajo se desarrolla una metodología basada en el Método de los Elementos Finitos para estudiar el equilibrio y la estabilidad de placas apoyadas en fundaciones elásticas. La formulación utilizada para el análisis de placas es válida para el análisis lineal y no lineal de placas isotrópicas o ortotrópicas, perhechas o inicialmente imperhechas. Esta formulación tiene como base las teorías de placas de Mindlin y von Kármán y en la teoría propuesta por Marguerre. Las placas pueden estar apoyadas en fundaciones lineales o no lineales, que son modeladas utilizando elementos finitos isoparamétricos. La fundación no lineal contiene términos cúbicos y cuadráticos, de modo que permita una representación más realista del su comportamiento. En la obtención de los caminos no lineales de equilibrio de las extructuras, se utilizaron diferentes métodos incrementales iterativos. Con el objetivo de considerar el problema de contacto unilateral, se implementan dos formulaciones que utilizan técnicas de Programación Matemática, una para el análisis lineal y otra para el análisis no lineal. Además de esas formulaciones, el problema de contacto unilateral puede ser tratado a través del uso de un modelo constitutivo de fundación no resistente a la tracción, que también es implementado en este trabajo. Se presentan ejemplos de equilíbrio y de estabilidad y, cuando posible, se comparan los resultados con los existentes en la literatura. A través de estos ejemplos, se estudia la influencia de la no linealidad de la placa y de la fundación, de las imperfecciones geométricas iniciales y del tipo de contacto (unilateral o bilateral) en la capacidad de carga y la estabilidad de la placa. También se discute la influencia del uso de diferentes mallas de elementos finitos em estos resultados, así como la eficiencia computacional de las metodologías utilizadas para tratar el contacto unilateral.

The historical narrative and our understanding about the low dose effects of radiation on the immune system has changed drastically from the beginning of the 20th century to now. A paradigm shift from the DNA target hit model to the one that also considers non-targeted effects (NTE) has attracted a lot of interest recently. Investigations to delineate mechanisms of NTE in the biological tissue have been carried out by various research groups where radiation induced genomic instability (RIGI), bystander effect (RIBE) and abscopal effect (AE) are the effects with most evidence available. This thesis addresses the question of whether low dose ionizing radiation (LDIR) stimulates or suppresses the immune system and how NTEs contribute to this immune modulation by adopting a two-pronged approach where first a narrative review constituting the introduction and literature review was performed followed by a systematic review using PRISMA guidelines to synthesize existing LDIR literature. This was prompted by our recent discovery that UVA photons are emitted by the irradiated cells and that these photons can trigger bystander effects in unirradiated recipients of these photons. Given the well-known association between UV radiation and the immune response, where these biphotons may pose as bystander signals potentiating processes in deep tissues as a consequence of ionising radiation, it is timely to revisit the field with a fresh lens. After reviewing various pathways and immune components that contribute to the beneficial and adverse effects induced by LDIR, it was found that these modulations can occur by way of NTE. However, the exact mechanistic underpinnings are still unclear and the literature examining low to medium dose effects of ionising radiation on the immune system is complex and controversial. Early work was compromised by lack of good dosimetry while later work mainly focuses on the involvement of immune responses in radiotherapy which typically uses high dose radiation. There is a lack of research in the LDIR/NTE field focussing on immune responses although bone marrow stem cells and lineages were critical in the identification and characterisation of NTE. This may be in part, a result of the difficulty of isolating NTE in whole organisms which are essential for good immune response studies. Models involving inter organism transmission of NTE are a promising route to overcome these issues. It is concluded that the simple question of whether LDIR stimulates or suppress the immune system is not as simple as initially hypothesized. An attempt was made to analyze if LDIR shifts the balance to immune suppression or enhancement via systematic review but, due to too many differences in the experimental methods in the current radiation and immune studies, a cookie-cutter answer was not possible. However, this thesis did point out the areas of concern such as lack of standardised tools in the field of radiobiological experimental research and quality of methods used which requires urgent attention. / Thesis / Master of Science (MSc)

<p>The effect of ultrasonic absorptive coatings on hypersonic boundary-layer transition on a 3 degree half-angle cone was investigated in Purdue's Boeing/AFOSR Mach 6 Quiet Tunnel for Reynolds numbers from 9.0-14.3 X 10⁶ /m. Silicon-carbide coated carbon foam with two densities, estimated at 100 and 200 pores per inch, are referred to throughout this work as X1 and X2 respectively. Both foams were fabricated as three frustums applicable to different locations on the cone. Matching solid pieces were made to test solid-porous configurations to analyze the effect of porous material length and location. Ultrasonic benchtop experiments have been carried out to characterize absorption coefficient values for the X1 and X2, quantifying the levels of acoustic energy absorbed by each foams, and enable companion linear stability calculations. </p> <p><br></p> <p>The most effective placement of both X1 and X2 foams towards achieving transition delay was in their most downstream position, spanning 59.2 cm to 74.3 cm downstream of the nosetip. The overall length of the cone was 109.1 cm. When the X1 foam covered more area, spanning from 44.1 cm to 74.3 cm, the same delay is observed with an unexpected increase in second-mode amplitude. In the same configuration, the X2 foam caused an increase in amplitude, without achieving delay. Agreement is observed against companion linear-stability theory calculations for the impermeable case, and for X1 and X2 foam in the configuration spanning from 44.1 cm to 74.3 cm. Finally, numerical modeling predicts the insurgence of an unexpected low-frequency mode. This was consistent with experimental results observed with the upstream placement of the foam inserts.  </p>

Context: Chronic ankle instability (CAI) individuals experience residual symptoms including pain, swelling, ankle instability, etc. A small majority of CAI individuals report ankle pain during daily or physical activity. Despite the known negative effects of chronic pain on neuromuscular control, there is a paucity of research exploring the specific impact of chronic pain mechanisms on altered neuromuscular control in CAI individuals. Purpose: The purpose of this study was to identify the effects of pain levels on static and dynamic postural control and visual reliance in CAI individuals. Methods: A total of 60 participants were recruited, consisting of 20 CAI individuals with high pain, 20 CAI individuals with low pain, and 20 healthy controls. Participants performed static postural control with eyes open and closed, the star excursion balance test (SEBT), and single-leg hop stabilization. One-way ANOVA assessed differences in Romberg ratios, SEBT, dynamic postural stability index, and self-reported outcomes. Two-way ANOVA (3x2) was used to assess differences in static postural control across the three groups. Results: The high pain group showed decreased mediolateral (ML) direction of static postural stability in eyes closed and a higher Romberg ratio in ML direction compared to the low pain group. The high pain group showed decreased reach distance and increased dynamic postural control in vertical and dynamic postural stability index compared to the healthy control group and low pain group, respectively. Conclusions: The levels of chronic pain can have a significant impact on both static and dynamic postural control and visual reliance in CAI individuals. Therefore, fluctuating chronic pain levels may result in alterations in motor outcomes.

No description available.

The detection of variable stars in open clusters is an essential component of testing stellar structure and evolution theories. The ability to detect low-amplitude variability among cluster members is directly related to the quality of the photometric results. Point Spread Function (PSF) fitting is the best method available for measuring accurate magnitudes within crowded fields of stars, while high-precision differential photometry is the preferred technique for removing the effects of atmospheric extinction and variable seeing. In the search for new variable stars among hundreds or thousands of stars, the Robust Median Statistic (RoMS) is proven more effective for finding low-amplitude variables than the traditional error curve approach. A reputable computer program called DAOPHOT was used to perform PSF fitting, whereas programs, CLUSTER and RoMS, were created to carry out high-precision differential photometry and calculate the RoMS, respectively, on the open clusters NGC 225, NGC 559, NGC 6811, NGC 6940, NGC 7142, and NGC 7160. Twenty-two new variables and eighty-seven suspected variable stars were discovered, and time-series data of the new variables are presented.

The effects of propagation of a short internal gravity wave through an inertia wave on internal wave stability is analyzed and parameterized. The interactions are specifically between a short wave packet and a large inertia wave packet. The short wave packet is a wave bounded with a Gaussian envelope with high frequencies and scales in the hundreds of meters horizontally and tens of meters vertically. The inertia wave packet is also an enveloped wave but with frequencies close to the rotation of the earth and scales in the thousands of meters in the horizontal and hundreds of meters in the vertical. The wave-wave interactions are modeled using ray theory and 2d non-linear numerical models. Ray tracing is used because it is less computationally expensive, however it fails at regions of strong refraction also known as caustics. To measure stability the steepness is calculated from the 2d non-linear methods and it is compared with estimates found in the linear theory. It is determined that the estimates of the short wave steepness from linear theory are qualitatively comparable. A quantifiable comparison, although more difficult, resulted in adjustment factors to the ray tracing results. It is also found that for the particular cases modeled, convective instabilities are predominant and the influence of the shear exerted by the large inertia wave is insignificant. Instability time scales are included in the stability analysis and estimates of overturning and wave-breaking are developed for different wave-wave interactions. From the stability analysis it is found that in general the faster the short wave propagates the more likely it is to conform to both of the conditions required for wave breaking (i.e presence of instabilities and instability time scales longer than the timescale of the short wave).

After the collapse of the roof structure in Tarfalahallen 2020, great attention has been focused on instability of sub-tensioned glulam roof trusses. Investigations were launched to find the reason for the collapse and the cause was instability in the roof truss that supported the roof. As a result, several similar glulam roof trusses in Sweden have been investigated and reinforced to avoid the fate of Tarfalahallen.Inexperience with instability, negligent design procedure and faulty assumptions is an underlying issue with this type of structure. Complex structures can be difficult to analyze without suitable assumptions which means sophisticated method must be used. Proper analysis must be done before construction.To perform this sophisticated analysis, an engineer can use the finite element method to perform global stability analysis. Simple and computationally cheap models can produce meaningful insight, but in most cases the user must be experienced to understand the implications of the results that the finite element method can produce. There is therefore a need for a more detailed, realistic model that can capture failure and motion and visualize it for the user. This thesis has created such a model in the FE-software Abaqus/Standard.By using a wide variety of elements and element sizes a detailed geometry of the connection between primary beam and compression stud, the behavior of the structural components has been analyzed throughout the loading period of the structure. The critical buckling mode was identified, and the complex non-linear interaction of the connection was tracked when buckling occurs.The thesis can be used as a guideline of how to create a FE-model that captures the intricate behavior of the connection between primary beam and compression stud and be used as the groundwork for more complex models in the future.