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Characterization of a Carbon Fiber Based Broadband Microwave Absorber
Get PDFThis paper reports the development and characterization of a novel ultra-wideband microwave absorber material (MAM) based on vertically aligned carbon fibers and ferrite beads. This specific material combination and manufacturing process allows MAM design that is thin, lightweight, and broadband. The material is prepared using a flocking process in which its components are electrostatically deposited on top of an adhesive substrate. Distinct material properties of the substrate and materials layers require characterization done with two separated layers. The microwave absorption characteristics are studied first by rectangular waveguide measurements at X and Ku bands that yield complex electric permittivity and magnetic permeability of the MAM samples without any metal backing. Here, the sample is measured under transverse electric waves ( ). Additional analysis is accomplished with full electromagnetic (EM) simulation using a high-frequency structure simulator (HFSS). The scattering parameters (S-parameters) from waveguide measurements and HFSS simulations are compared and excellent agreement is achieved. Extracted material parameters are also used to analytically calculate the reflection loss (RL) based on the transmission line model. The transmission line model shows excellent agreement with the full EM simulation results which should speed up future studies. Finally, the broadband RL performance of MAM was investigated using a free space spot probe system. The results show a MAM with broadband performance of − 10 dB RL over the entire X and Ku bands. Overall, this study demonstrates that MAM developed using magnetically loaded flocked carbon fiber (MLF-CF) has a promising combination of low-cost, lightweight, and broadband performance
An Exploration of Self-Efficacy and Its Associated Factors Among Rheumatoid Arthritis Patients in Taiwan
Get PDFSelf-efficacy is an important ingredient in successful disease management, especially in patients with chronic conditions such as rheumatoid arthritis (RA). However, the information on self-efficacy and its influencing factors among RA patients is scarce. This study investigated the level of self-efficacy and its pertinent predictors among RA patients in Taiwan. This cross-sectional study recruited patients with RA from a hospital in Taiwan between January and October 2023. A structured questionnaire was used to collect data on respondents’ demographic and job characteristics and included a Chinese version of the Arthritis Self-Efficacy Scale (ASES). Multiple linear stepwise regression analysis was employed to identify predictors of self-efficacy. A total of 284 RA patients were enrolled during the study period. The mean ASES score among enrollees was 1607.1, indicating a moderate level of self-efficacy (score range of 200–2000). The regression model displayed that those with higher disease activity scores, Taiwanese Depression Questionnaire scores, fatigue level, shorter disease duration, swollen upper limb joints, and no regular exercise regimen reported lower ASES scores, accounted for 46% of the total variance. The study findings may be useful for healthcare providers in identifying RA patients with low self-efficacy attitudes, a trait that appears to be linked to several medical indicators, and thus facilitating the provision of future tailored healthcare regimens
Sharing Stories of Hope and Transformation in U.S. Higher Education: An eReader by Portland State University Students
Get PDFThis eReader showcases stories of hope and transformation written by diverse students enrolled in University Studies courses at Portland State University. The goal is to motivate first-year and transfer students to see that, in higher education, they are not alone in their personal, familial, and academic struggles—and personal, familial, and educational achievements.https://pdxscholar.library.pdx.edu/pdxopen/1050/thumbnail.jp
Improving Attendance to Achieve Organizational Goals: A Case Study of Human-Centered Design in a Small US Plant-Based Food Manufacturer
Get PDFPlant-based food manufacturing companies face high staff turnover rates and attendance problems. It is challenging for those companies to maintain an acceptance level of employee retention and attendance to achieve their objectives. Companies rely on front-line employees to meet production plans, but employees who do not show up at work jeopardize companies\u27 operations. Additional challenges, such as retaining and attracting talent after the COVID-19 pandemic, are present daily for several U.S. organizations. This study analyzes attendance data from the case study company to design an attendance policy. Attendance data suggested that nearly 60 percent of the operational workforce had attendance or punctuality problems. The research project was conducted in a small company located in the U.S. that manufactures plant-based food following the human-centered design (HCD) methodology to design a four-level attendance policy: 1) good standing, 2) improvement, 3) disciplinary, and 4) termination. The new attendance policy is designed and implemented by incorporating literature review gaps, feedback from other companies with similar workforce populations, and including the needs of the staff and not solely those of the company. After a successful project management design, training, and implementation, the expected goals are to reduce employee absenteeism, decrease the number of new hires and training hours, and increase the likelihood that the company meets its organizational goals
A Magnetic Constant Torque Mechanism
No full textThis paper presents the design of a new type of magnetic constant torque mechanism. The constant torque is shown to be created over a prescribed ±65° stroke length and is shown to be highly uniform. The value of the constant torque is adjustable through the relative axial motion of the rotors. The constant torque is created using a simple magnet arrangement which makes use of the axial transverse-flux path of one rotor\u27s magnetic field relative to the azimuthal field flow of the fixed secondary rotor. It is shown that the use of segmented magnets introduces torque ripple
Cognitive Apprenticeship Strategies for the Media Literacy Classroom
Get PDFInspired by the apprenticeship model of teaching and learning, two instructors report on their efforts to place current events at the center of a semester-long media and information literacy course. They discuss strategies to harness curiosity about contemporary topics (e.g., misinformation, climate change, algorithms, right-to-repair, blockchain, artificial intelligence, etc.), and create engagement-driven course content. The paper provides concrete examples of activities and assignments used to situate learning in real-world contexts and build students\u27 confidence in navigating information independently. This case study offers insights for other educators seeking to apply cognitive apprenticeship principles to media and information literacy instruction
School-Based Health Centers and Mental Health Stigma Before and During the Pandemic
Get PDFThe mental health of children, and especially adolescents, has been a global public health priority for decades. School-based health centers (SBHCs) are health clinics established in close proximity to elementary and secondary schools for the purpose of increasing access to medical, and particularly mental health services, for children and adolescents. Yet, like other health clinics, SBHCs struggle to overcome structural and interpersonal stigma related to mental health conditions and support. Then, the pandemic threatened the sustainability and efficacy of SBHCs just as youth\u27s mental health needs skyrocketed. We use Stangl et al.’s (2019)framework for health-related stigma to analyze data from 36 interviews with SBHC Coordinators in Oregon and their Educator Partners to investigate: 1) What implications does mental health-related stigma have for SBHCs\u27 delivery of mental health services to children and adolescents? 2) How did these factors change during the pandemic? Consistent with Stangl et al.’s (2019) framework for health-related stigma, mental-health-related stigma is evident in this study in terms of the secondary stigma youth are reported to experience from peers and families in terms of visiting a SBHC for mental health services, as well as in limitations in the quantity and quality of resources dedicated to providing mental health services. The pandemic had contradictory effects, both increasing and reducing stigma along two axes: cultural perceptions of mental health problems and telehealth
Characterizing the Influence of Metabolism on Steady State Water Exchange in Yeast as a Potential MRI Diagnostic Biomarker
Get PDFUnder conditions of ionic equilibrium with the environment a cell maintains a constant volume yet rapidly exchanges water molecules with the extracellular space. The rate constant for steady state water efflux, kio, can be measured using contrast enhanced magnetic resonance (CE-MR). The active water cycling (AWC) hypothesis is puts forward that kio is primarily influenced by cellular ATP levels and H+ ATPase activity at the cell membrane. Due to the correlation between kio and ATP levels, kio is thought to be a probable MRI biomarker for metabolic diseases such as cancer. Yet, the molecular mechanisms that drive kio remain incompletely understood. The objective of this work is to understand the molecular metabolic origins of differences in kio using yeast (S. cerevisiae) as a model organism. The AWC hypothesis is the main hypothesis in the field and came about when. yeast cells were observed when grown in batch culture. However, batch culture yields an inhomogeneous population of cells and promotes a changing of metabolic profile overtime. A homogenous platform of cells is required to provide support for the AWC hypothesis and further characterize the molecular mechanisms that drive kio.
In this work yeast cells were grown in chemostats, where cell culture of uniform metabolic state was obtained. Low and high glucose concentrations were used to promote distinct metabolisms: respiratory or fermentative. Respiring cells demonstrated higher values of kio in addition to greater ATP levels compared to respiro-fermenting cells. The results indicate that kio can be used to differentiate cell cultures utilizing different metabolic pathways. Tumors are known to be metabolically heterogonous and exhibit regions of both fermentative and hyper-respiratory metabolic state. The experiments presented here presumably suggest that kio could be used to delineate these regions and inform targeted treatment for cancer.
The relationship between kio, cellular ATP concentration, and mitochondrial activity was investigated in yeast as a metabolic model for the Warburg effect. The Warburg effect is defined by upregulation of fermentation, even in the presence of oxygen. Using chemostat cultures of yeast the impact of mitochondrial modulators (2,4-Dinitrophenol (DNP) and oligomycin A) on kio and ATP levels was investigated. Exposure to mitochondrial inhibitors elicited distinct responses: Oligomycin A exposure led to an increase in ATP but a weaker response in kio. This result is likely due to yeast exhibiting oligomycin resistance and requires further investigation. The addition of increasing concentrations of DNP caused a hormetic effect on measured ATP levels. kio was strongly correlated with ATP levels up to a concentration of 750 μM DNP. DNP is known to modulate the membrane potential in the mitochondria. Exposure to DNP caused a twofold change in measured kio values compared to no DNP added. This experiment represents the most significant finding of this work; that kio can be affected by intracellular processes at the mitochondria
It\u27s Going to be Okay: Experiences and Perceptions of People Who Seek Reassurance at Work
No full textThis study examined the experiences and perceptions of people who seek reassurance at work using a mixed methods (focus groups and experimental) approach. Reassurance-seeking is an attempt to elicit supportive communication from another person to help one reduce experienced anxiety. First, using focus groups with 32 participants, this study found that people seeking reassurance at work develop complex cognitive structures to reduce the prospective negative impacts of reassurance-seeking behaviors, particularly for those with marginalized identities. Then, in a 3x2 between-person experimental design in which employee gender and reassurance-seeking were manipulated, participants read a transcript of an interaction between an employee and a supervisor. In the reassurance-seeking condition, the employee sought and was provided with reassurance; in the control condition, participants did not seek reassurance, but the supervisor provided the same reassurance. Participants then indicated their perceptions of employee competence, performance, social burden, and promotability; assigned a compensation amount; and indicated ostracism intentions. As hypothesized, participants perceived those who sought reassurance as less competent, which led to lower perceptions of promotability and a lower assigned compensation value. These negative impacts depended on the gender of the reassurance-seeker--non-binary people experienced the worst outcomes. Focus group participants indicated that offering proactive reassurance regarding known anxiety-inducing factors would prevent the need for reassurance-seeking and save time spent worrying. Harmonious experimental findings suggest offering proactive reassurance to prevent reassurance-seeking (when possible) would prevent the negative biasing of competence perceptions and particular bias based on gender
A Contemporary Examination of Racial Intraminority Relations: Attitudes, Motivations, and Barriers to Participation in Collective Action
Get PDFSocial movements globally and within the U.S. are gaining widespread acknowledgment as many individuals become more aware of systems of disadvantage and oppression, gain a better understanding of their root causes, and engage in collective ways to approach social change. Social science research on engagement with collective action has started to go beyond looking only at majority-minority relations (such as between White and Black people) to examine solidarity and coalition building between minoritized groups. This dissertation expands the literature both on collective action and intraminority intergroup relations through three manuscripts. Chapter II explores various social attitudes (e.g., awareness of privilege and oppression, just world beliefs, social dominance orientation) and their predictive roles on engagement with the Black Lives Matter movement across target, dominant, and non-target minority third groups (Lake & Kahn, under review), specifically highlighting the common predictive role of awareness of privilege and oppression across groups. Chapter III explores the effects of feelings of closeness with other minoritized groups (e.g., outgroup warmth, outgroup trust, identity fusion, common fate) on collective action, identifying the significant roles of feelings of warmth towards a target group and perceptions of common fate with other communities of color on intraminority solidarity specifically. Chapter IV samples current social justice activists and community organizers of color to test relationships between common predictors and outcomes included in models of collective action (e.g., identity, perceived injustice, collective efficacy), showing the prominent role of both racial and activist identity centrality in predicting intraminority solidarity. Additionally, Chapter IV qualitatively examines the motivations and barriers of participating in collective action for the individual and intraminority coalition building. Studies in this dissertation use multiple methods, including cross-sectional surveys with quantitative and qualitative data, with diverse samples from student samples to national samples to self-identified activists and community organizers of color. Together, the studies fill gaps in the literature on both collective action and intergroup relations by further examining and providing new knowledge on known predictors and models within specific social contexts and between racial minority groups. Findings provide implication for both development of theories and models of collective action, and for practical strategies for social movement building and sustainability