48670 research outputs found
Sort by
Black and African American Women Postdocs in STEM: Their Experiences and Career Plans
No full textWithin the education-to-career pathways, what is largely absent from the literature regarding women and underrepresented minorities’ (URM) participation in science, technology, engineering and math (STEM) disciplines are a complete understanding of their entrance into the employment sector immediately following the completion of a doctoral degree (Jaeger et al., 2017). For many doctoral graduates, the first position following the conferral of a doctoral degree is often a postdoctoral position (NSF, 2019a). Postdoctoral fellowships (postdocs) have been seen as a necessary prerequisite and critical entry point into future careers in STEM (Chen et al., 2015; Hudson et al., 2018; Su, 2013). Postdoc positions often serve as opportunities for newly minted doctoral degree recipients to engage in continued mentorship, on-going research training, as well as socialization into their respective disciplinary domains (Akerlind, 2005; Kaslow & Mascaro, 2007; Margolis & Romero, 1998). While literature is emerging that speaks to the experiences of postdoctoral women and URM (Lambert et al., 2020; Yadav & Seals, 2019), there still exists a need for research that looks within these groups given their distinct attributes at the intersection of race and gender (Ireland et al., 2018). This qualitative study explores the experiences and perceived career trajectories of 33 United State citizen and/or permanent resident who self-identified as Black and African American women with earned STEM doctoral degrees, who were also employed in the U.S. as postdocs at the time of the semi-structured one-on-one interviews. Using science identity and research self-efficacy as lenses to contextualize their experiences, this research expands the understanding of and the utilization of these factors, as well as the emergence, absence or presence of advocacy from others and from within themselves as they advance in their careers
Subtyping Chronic Kidney Disease Patients and Adiposity-Obesity Related Metabolomics Analyses: Findings from the Chronic Renal Insufficiency Cohort Study
No full textChronic kidney disease (CKD) is a heterogenous condition that is often complicated by multiple serious comorbidities that create a large disease burden. Concurrent with the high CKD prevalence is the epidemic of obesity which increases the risks of adverse outcomes among people with kidney dysfunction. However, due in part to patient heterogeneity, the complex relationship between obesity and CKD is not fully understood. We aim to systematically examine phenotypic heterogeneity in patients with CKD and to study CKD mechanisms related to obesity-adiposity by integrating rich clinical characteristics of patients with high-dimensional metabolomics data. 3939 participants in the prospective Chronic Renal Insufficiency Cohort (CRIC) Study with stage 2-4 CKD at baseline were included in this body of research. We conducted two parallel clustering analyses using the machine learning methods of consensus clustering. First, we examined the overall CKD heterogeneity using 72 markers of patients’ demographics, biomarkers, and commonly collected clinical characteristics. Second, we identified the adiposity-obesity-related (AOR) CKD subgroups using 22 markers of patients’ obesity attributes, adiposity parameters, and comorbidity profiles. Third, in a random subset of CRIC participants with metabolomics data, we investigated the metabolic signatures associated with AOR CKD subgroups and tested metabolites as potential mediators of the association between AOR CKD subgroups and various clinical endpoints using Aalen additive hazards models and Cox regression. Among our findings, we identified three distinct CKD subgroups from the overall clinical data, and a different set of three-level AOR CKD subgroups featured with distinct patient profiles of adiposity/obesity and diabetes. Both sets of CKD subgroups were significantly and independently associated with different rates of future clinical outcomes. The metabolomics and mediation analyses revealed numerous metabolites to be mediators of the relationship between AOR CKD subgroups and clinical endpoints. Among them, multiple lipids, nucleoside, and amino acid metabolites were identified as key markers. In summary, our work quantitatively characterized CKD patient heterogeneity, shed light on adiposity-obesity-related disease mechanisms at both phenotypic and molecular levels, and highlighted potential therapeutic targets as well as metabolomics pathways for disease management and treatment. Validation using longitudinal metabolomics data and/or independent cohorts are needed
Euler Calculus, Euler Integral Transforms, and Combinatorial Species
No full textEuler integration is an integration theory with the Euler characteristic acting as the measure, and similar to classical analysis, it comes equipped with a collection of integral transforms. In this thesis, we focus on two such integral transforms: the persistent homology transform and the Fourier-Sato transform. We prove the invertibility of the former using the technique of Radon transform, and show the connection of the latter to Euler convolution and inner product. We also provide a new way to interpret the Euler integral through a generalization of combinatorial species, which also extends to magnitude homology and configuration spaces
Educational Trajectories of Indigenous Students: Vertical and Horizontal Stratification in the Chilean Educational System
No full textMultiple studies connect ethnic background with uneven educational outcomes; this study contributes a novel perspective to the literature by attending to indigenous peoples’ experiences with vertical and horizontal dimensions of stratification in the Chilean school system. This dissertation investigates the transition from primary to secondary school and to higher education, comparing enrollment in academic and vocational tracks at the secondary and tertiary levels. It then investigates the choice of field of study among students who enroll in higher education. Finally, it compares the educational trajectories of indigenous and non-indigenous student cohorts who entered higher education before and after the post-2011 free-of-charge policy. With a series of logistic regressions, I investigate differences in critical educational transitions associated with indigenous status, together with gender and location. Analyses of the 2012 seventh-grade cohort shows that indigenous status increases the likelihood of enrolling in vocational high schools, but regarding the transition to higher education, indigenous status is only relevant when school SES is not included. Nevertheless, vocational high school graduates (where indigenous students concentrate) are less likely to enroll in higher education, and more likely to enroll in vocational instead of academic higher education programs. Furthermore, in higher education, indigenous students are more likely than non-indigenous peers to enroll in vocational Engineering, Industry and Construction programs and vocational Health and Social Services programs, while they are less likely to enroll in academic Social Sciences, Management, and Law programs. However, controlling for school SES renders these differences irrelevant. Previous cohorts show little variation in the transition into higher education for the 2015-2018 period. However, there is some indication of a shrinking gap in enrollment rates between vocational and academic high school graduates, a reduction of enrollment in vocational higher education programs after 2016, and a declining impact of school characteristics. Overall, indigenous status has a clear impact on students\u27 transition from middle school to high school, which has relevant consequences for the transition to higher education. While indigenous status loses salience in this latter transition, gender, and type of high school strongly affect the choice of higher education field of study and type of program
A New What About the Children Question: Examining the Experiences of Second-Generation Black-White Multiracials
No full textFor four decades, scholars have analyzed the experiences of individuals on the nexus of multiple racial categories to understand racial identity and racial boundaries. However, most of the research on how Multiracials navigate racial lines is limited to first-generation Multiracials. To my knowledge, there has yet to be a qualitative study on how those in the second-generation of racial mixing racially identify and are identified by others (reflected race). I argue that including second-generation multiracials provides new insights to our understanding of racial identities and boundaries through interviews with 99 second-generation Black-White Multiracials. I find that second-generation Multiracials have higher Multiracial categorizations in Article 1 on racial categorizations and few are exclusively viewed as Black in Article 2 on reflected race. Additionally, I find that they experience racial imposter syndrome, or feeling like a racial fraud, as a result of not being in the first-generation of racial mixing in Article 3. My dissertation reveals the necessity of including the monoracial parent’s background when looking at generational status as racial categorizations, reflected race, and racial imposter syndrome differ between those with a monoracial White parent and those with a monoracial Black parent. I argue that these findings point to a shift in widening of Whiteness and narrowing of Black boundaries
Examining the Educational Experiences and Obstacles of Syrian Refugees in Lebanon
No full textThe international community is currently witnessing the highest influx of forced migration, displaced people, and refugees compared to any other time in history. More than 230 million people worldwide have fled their homes, seeking refuge elsewhere due to war and political, economic, and environmental upheaval. The impact of refugees on the environment and infrastructure is monumental. For this reason, setting policies and programs and managing the needs of refugees are instrumental to the hosting countries. Among other concerns, there is a need to examine the educational initiatives that teach a transitioning population. Evaluating education programs is crucial to understanding their effectiveness and recommending policy and implementation changes for future efforts. This qualitative research study examines the educational experiences and obstacles of Syrian refugees enrolled in middle schools in Lebanon. In this study, I found that the academic shortcomings are mainly due to the massive volume of refugees and ratio per population and its effect on Lebanon\u27s infrastructure, coupled with a lack of resources provided by international players, country donors, and nongovernmental organizations. The research delves into the perspectives of families and educators and uses a comparative approach to review the existing literature to deduce general trends and patterns of various refugee educational cases in Lebanon and developing countries. In this study, I used a qualitative methods approach by conducting interviews, focus groups, and surveys in a sample of students, principals, educators, and parents in four schools in Lebanon. In the findings of this study, I present four interconnected keys representing my theoretical construct: (a) disclosing aspects of support, (b) building a balanced curriculum, and (c) developing an integration process in school and in the community, and (d) social and emotional experiences. I discuss how my study informs and improves education policies and the effectiveness of refugee education programs in Lebanon and other hosting countries
Reimagining Robotic Walkers For Real-World Outdoor Play Environments With Insights From Legged Robots: A Scoping Review
Get PDFPURPOSE
For children with mobility impairments, without cognitive delays, who want to participate in outdoor activities, existing assistive technology (AT) to support their needs is limited. In this review, we investigate the control and design of a selection of robotic walkers while exploring a selection of legged robots to develop solutions that address this gap in robotic AT. METHOD
We performed a comprehensive literature search from four main databases: PubMed, Google Scholar, Scopus, and IEEE Xplore. The keywords used in the search were the following: “walker”, “rollator”, “smart walker”, “robotic walker”, “robotic rollator”. Studies were required to discuss the control or design of robotic walkers to be considered. A total of 159 papers were analyzed. RESULTS
From the 159 papers, 127 were excluded since they failed to meet our inclusion criteria. The total number of papers analyzed included publications that utilized the same device, therefore we classified the remaining 32 studies into groups based on the type of robotic walker used. This paper reviewed 15 different types of robotic walkers. CONCLUSIONS
The ability of many-legged robots to negotiate and transition between a range of unstructured substrates suggests several avenues of future consideration whose pursuit could benefit robotic AT, particularly regarding the present limitations of wheeled paediatric robotic walkers for children’s daily outside use.
For more information: Kod*lab (link to kodlab.seas.upenn.edu
Volatile Organic Compound Detection and Disease Diagnostics Using DNA-Functionalized Carbon Nanotube Sensor Arrays
No full textThere is a strong desire for novel chemical sensors that can detect low concentrations of volatile organic compounds (VOCs) for early-stage disease diagnostics as well as various environmental monitoring applications. The aim of this thesis work was to address these challenges by developing an “electronic nose” (e-nose) platform based on chemical sensor arrays capable of detecting and differentiating between various VOCs of interest. Sensor arrays were fabricated in a field-effect transistor (FET) configuration with exquisitely sensitive carbon nanotubes (CNTs) as the channel material. The nanotubes were functionalized with a variety of single-stranded DNA oligomers, forming DNA-NT hybrid structures with affinity to a wide variety of VOC targets. Interactions between DNA-NTs and VOCs yielded changes in sensor conductivity that depended strongly on the base sequence of DNA. Arrays of CNT devices were functionalized with up to ten different DNA oligomers to enable electronic signature readouts of VOC binding events. DNA-NT responses were processed with pattern recognition algorithms in order to classify different VOC targets according to their chemical “fingerprints.” This technology was used to measure VOC biomarkers associated with ovarian cancer and COVID-19 from human fluid media. DNA-NT arrays measured headspaces VOCs from 58 blood plasma samples from individual people, including 15 with a late-stage malignant form of ovarian cancer, 6 with early-stage malignant cancer, 16 with a benign form of cancer, and 21 healthy age-matched controls. Statistical techniques based on machine learning were used to discriminate between the malignant, benign, and healthy groups with 90 – 95% classification accuracy. Furthermore, all six early-stage samples were correctly identified with the malignant group, indicating significant progress towards an effective screening method for ovarian cancer. Similar investigations were conducted on sweat samples procured from patients who had tested positive for COVID-19 (CoV+) and those who had tested negative (CoV-). Statistical analysis of the DNA-NT responses to the sweat headspace VOCs revealed highly differentiated clusters associated with the CoV+ and CoV- groups. A binary classifier was constructed using the response data and was estimated to have a 99% classification success rate, suggesting strong potential for utilizing DNA-NTs for COVID screening. Finally, DNA-NT arrays were assessed based on various performance characteristics desired for remote environmental monitoring applications such as pollution monitoring and explosives detection in a warzone. A series of experiments was conducted to evaluate DNA-NT sensitivity, specificity, and longevity using mixtures of 2,6-dinitrotoluene (DNT) and dimethyl methylphosphonate (DMMP) to simulate complex VOC environments. The sensors demonstrated sensitivity to parts-per-billion concentrations of DNT in a highly concentrated background of DMMP. Moreover, the shelf life of these sensors was projected on the order of months, making DNA-NTs promising candidates for a wide range of applications
Elucidating the Role of the African-Centric P47s Variant of TP53 in Metabolism and Ferroptosis
No full textThe tumor suppressor gene TP53 is the most frequently mutated gene in cancer and plays a key role in mediating several processes that are critical for preventing tumor formation and progression. Known as the guardian of the genome, p53 regulates hundreds of genes involved in various pathways such as apoptosis, cell cycle arrest and senescence. In recent years, the role of p53 in metabolism, redox state and ferroptosis has begun to emerge. Our lab has identified an African-specific polymorphic variant of p53 that encodes a serine residue instead of a proline at amino acid 47 (hereafter S47) and predisposes carriers to cancer. The S47 variant is impaired for tumor suppression and ferroptosis, and S47 cells have an altered redox state. We sought to use the tumor prone S47 model as a tool to better understand the role of p53 in tumor suppression. Our results demonstrate that mice carrying the S47 variant have greater metabolic efficiency compared to those with WT p53, along with increased mTOR activity. This difference in mTOR stems from an impaired protein-protein interaction that occurs in S47, ultimately due to a difference in cellular redox state. We next identified PLTP as a p53 target gene that shows decreased transactivation in the S47 variant and mediates ferroptosis resistance by enhancing lipid storage in HepG2 cells. Taken together, this work sheds light on the emerging roles p53 plays in tumor suppression, metabolism and ferroptosis. It also provides a better understanding of an ethnic genetic variant of p53. We expect this work will enable better personalized medicine approaches and therapeutic options for people who carry this variant
Search for Trilepton Resonances from R-Parity Violating Chargino Decays in the B−L MSSM
No full textThis dissertation presents a search for the electroweak pair-production of charginos and the associated production of charginos and neutralinos in the B−L Minimal Supersymmetric Standard Model with spontaneous R-parity violation. The chargino and neutralino each decay via R-parity violating couplings to a charged lepton or neutrino and a W, Z, or Higgs boson. This analysis searches for resonances in the trilepton invariant mass spectrum, targeting events with charginos decaying to three electrons or muons via a leptonically decaying Z boson. The dataset includes 139 fb-1 of √s = 13 TeV proton-proton collisions produced at the Large Hadron Collider and collected by the ATLAS detector. With no significant excess observed, limits are set on chargino and neutralino masses between 100 GeV and 1100 GeV, depending on the assumed branching fractions to leptons (electron, muon, or r-lepton) and bosons (W, Z, or Higgs)