1,102 results on '"D Pearce"'
Search Results
2. Remote Administration of Physical and Cognitive Performance Assessments in a Predominantly Black Cohort of Persons With Systemic Lupus Erythematosus
- Author
-
Courtney Hoge, C. Barrett Bowling, Charmayne Dunlop‐Thomas, Brad D. Pearce, Cristina Drenkard, S. Sam Lim, and Laura C. Plantinga
- Subjects
Diseases of the musculoskeletal system ,RC925-935 - Abstract
Objective In a study of physical and cognitive functioning among predominantly Black individuals with systemic lupus erythematosus (SLE), we compared remotely administered physical and cognitive performance assessments to those collected in person. Methods A subset of participants who completed an in‐person visit in our parent study from 2021 to 2022 (n = 30) were recruited to complete a second, remote visit within 28 days. Physical performance (measured by a modified Short Physical Performance Battery [SPPB]; range 0‐12; subscale ranges 0‐4; higher = better performance) and cognitive performance (episodic and working memory adjusted t‐scores, measured using NIH Toolbox) were measured at both visits. Mean scores were compared using paired t‐tests; intraclass correlation coefficients (ICCs) were obtained from two‐way mixed effects models. Linear and logistic models were used to estimate stratified associations between performance measures and related outcomes. Results Participants were primarily female (93.3%) and Black (93.3%). In‐person versus remote overall SPPB (8.76 vs. 9.43) and chair stand (1.43 vs. 1.90) scores were statistically significantly lower. t‐Scores for episodic memory (47.27 vs. 49.53) and working memory (45.37 vs. 47.90) were lower for in‐person versus remote visits. The ICC for overall SPPB indicated good agreement (0.76), whereas the ICCs for episodic (0.49) and working memory (0.57) indicated poor‐moderate agreement. Associations between assessments of performance with related outcomes were similar and did not statistically significantly differ by modality of visit. Conclusion To possibly expand and diversify pools of participants in studies of physical and cognitive performance in SLE, remote administration of assessments should be considered for future research.
- Published
- 2023
- Full Text
- View/download PDF
3. Characterizing how One Health is defined and used within primary research: A scoping review
- Author
-
Sydney D. Pearce, David F. Kelton, Charlotte B. Winder, Jan M. Sargeant, Jamie Goltz, and E. Jane Parmley
- Subjects
global one health research ,knowledge synthesis ,one health applications ,one health definitions ,Medicine ,Medicine (General) ,R5-920 - Abstract
Background and Aim: One Health (OH) approach can be used in multiple ways to tackle a wide range of complex problems, making OH research applications and definitions difficult to summarize. To improve our ability to describe OH research applications, we aimed to characterize (1) the terms used in OH definitions within primary research articles reporting the use of the OH approach, and (2) the who, what, where, when, why, and how (5Ws and H) of the OH primary research articles. Materials and Methods: A scoping review was conducted using nine databases and the search term “One Health” in June 2021. Articles were screened by two reviewers using pre-specified eligibility criteria. The search yielded 11,441 results and screening identified 252 eligible primary research articles. One Health definitions and 5Ws and H data were extracted from these studies. Results: Definitions: One Health was labeled as an “approach” (n = 79) or “concept” (n = 30) that is “multi/cross/inter/trans-disciplinary” (n = 77), “collaborative” (n = 54), “interconnected” (n = 35), applied “locally/regionally/nationally/globally” (n = 84), and includes health pillars (“human” = 124, “animal” = 122, “environmental/ecosystem” = 118). WHEN: Article publication dates began in 2010 and approximately half were published since 2020 (130/252). WHERE: First authors most often had European (n = 101) and North American (n = 70) affiliations, but data collection location was more evenly distributed around the world. WHO: The most common disciplines represented in affiliations were human health/biology (n = 198), animal health/biology (n = 157), food/agriculture (n = 81), and environment/geography (n = 80). WHAT: Infectious disease was the only research topic addressed until 2014 and continued to be the most published overall (n = 171). Antimicrobial resistance was the second most researched area (n = 47) and the diversity of topics increased over time. HOW: Both quantitative and qualitative study designs were reported, with quantitative observational designs being the most common (n = 174). WHY: Objectives indicated that studies were conducted for the benefit of humans (n = 187), animals (n = 130), physical environment (n = 55), social environments (n = 33), and plants (n = 4). Conclusion: This scoping review of primary OH research shows a diverse body of work, with human health being considered most frequently. We encourage continued knowledge synthesis work to monitor these patterns as global issues and the application of OH approaches evolve.
- Published
- 2023
- Full Text
- View/download PDF
4. Toward Prebiotic Chemistry on Titan: Impact Experiments on Organic Haze Particles
- Author
-
Ben K. D. Pearce, Sarah M. Hörst, Christopher J. Cline, Mark J. Cintala, Chao He, Joshua A. Sebree, Shannon M. MacKenzie, R. Terik Daly, Alexandra J. Pontefract, and Cara Pesciotta
- Subjects
Lunar and Planetary Science and Exploration - Abstract
Impacts are critical to producing the aqueous environments necessary to stimulate prebiotic chemistry on Titan's surface. Furthermore, organic hazes resting on the surface are a likely feedstock of biomolecules. In this work, we conduct impact experiments on laboratory-produced organic haze particles and haze/sand mixtures and analyze these samples for life's building blocks. Samples of unshocked haze and sand particles are also analyzed to determine the change in biomolecule concentrations and distributions from shocking. Across all samples, we detect seven nucleobases, nine proteinogenic amino acids, and five other biomolecules (e.g., urea) using a blank subtraction procedure to eliminate signals due to contamination. We find that shock pressures of 13 GPa variably degrade nucleobases, amino acids, and a few other organics in haze particles and haze/sand mixtures; however, certain individual biomolecules become enriched or are even produced from these events. Xanthine, threonine, and aspartic acid are enriched or produced in impact experiments containing sand, suggesting these minerals may catalyze the production of these biomolecules. On the other hand, thymine and isoleucine/norleucine are enriched or produced in haze samples containing no sand, suggesting catalytic grains are not necessary for all impact shock syntheses. Uracil, glycine, proline, cysteine, and tyrosine are the most unstable to impact-related processing. These experiments suggest that impacts alter biomolecule distributions on Titan's surface, and that organic hazes co-occurring with fine-grained material on the surface may provide an initial source for further prebiotic chemistry on Titan.
- Published
- 2024
- Full Text
- View/download PDF
5. JWST/NIRCam 4–5 μm Imaging of the Giant Planet AF Lep b
- Author
-
Kyle Franson, William O. Balmer, Brendan P. Bowler, Laurent Pueyo, Yifan Zhou, Emily Rickman, Zhoujian Zhang, Sagnick Mukherjee, Tim D. Pearce, Daniella C. Bardalez Gagliuffi, Lauren I. Biddle, Timothy D. Brandt, Rachel Bowens-Rubin, Justin R. Crepp, James W. Davidson Jr., Jacqueline Faherty, Christian Ginski, Elliott P. Horch, Marvin Morgan, Caroline V. Morley, Marshall D. Perrin, Aniket Sanghi, Maïssa Salama, Christopher A. Theissen, Quang H. Tran, and Trevor N. Wolf
- Subjects
Extrasolar gaseous giant planets ,Direct imaging ,James Webb Space Telescope ,Exoplanet atmospheres ,Astrophysics ,QB460-466 - Abstract
With a dynamical mass of 3 M _Jup , the recently discovered giant planet AF Lep b is the lowest-mass imaged planet with a direct mass measurement. Its youth and spectral type near the L/T transition make it a promising target to study the impact of clouds and atmospheric chemistry at low surface gravities. In this work, we present JWST/NIRCam imaging of AF Lep b. Across two epochs, we detect AF Lep b in F444W (4.4 μ m) with signal-to-noise ratios of 9.6 and 8.7, respectively. At the planet’s separation of 320 mas during the observations, the coronagraphic throughput is ≈7%, demonstrating that NIRCam’s excellent sensitivity persists down to small separations. The F444W photometry of AF Lep b affirms the presence of disequilibrium carbon chemistry and enhanced atmospheric metallicity. These observations also place deep limits on wider-separation planets in the system, ruling out 1.1 M _Jup planets beyond 15.6 au (0.″58), 1.1 M _Sat planets beyond 27 au (1″), and 2.8 M _Nep planets beyond 67 au (2.″5). We also present new Keck/NIRC2 $L^{\prime} $ imaging of AF Lep b; combining this with the two epochs of F444W photometry and previous Keck $L^{\prime} $ photometry provides limits on the long-term 3–5 μ m variability of AF Lep b on timescales of months to years. AF Lep b is the closest-separation planet imaged with JWST to date, demonstrating that planets can be recovered well inside the nominal (50% throughput) NIRCam coronagraph inner working angle.
- Published
- 2024
- Full Text
- View/download PDF
6. Mental Stress-Induced Change in Plasma Stromal Cell-Derived Factor-1 and Adverse Cardiovascular Outcomes: A Cohort Study
- Author
-
Jeong Hwan Kim, MD, Zakaria Almuwaqqat, MD, MPH, Afif Martini, MD, Chang Liu, MPH, Yi-An Ko, PhD, Samaah Sullivan, PhD, Tiffany Dong, MD, Amit J. Shah, MD, J. Douglas Bremner, MD, Brad D. Pearce, PhD, Jonathan A. Nye, PhD, Viola Vaccarino, MD, PhD, and Arshed A. Quyyumi, MD
- Subjects
Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Background: Acute psychological stress can provoke mental stress-induced myocardial ischemia (MSIMI) in coronary artery disease (CAD). Stromal cell-derived factor 1 (SDF1) is released in response to hypoxia, and higher levels of SDF1 are associated with adverse outcomes. We examined whether an increase in SDF1 level in response to mental stress predicts adverse outcomes in CAD patients. Methods: A total of 554 patients with stable CAD (mean age 63 years; 76% male; 26% Black) underwent standardized mental stress testing. Plasma SDF1 levels were measured at rest and 90 minutes after mental stress, and MSIMI was evaluated by 99mTc-sestamibi perfusion imaging. Participants were followed for 5 years for the primary endpoint of composite of death and myocardial infarction (MI) and the secondary endpoint of composite of death, MI, and heart failure hospitalization. Cox hazard models were used to assess the association between SDF1 change and incident adverse events. Results: Mean (standard deviation) SDF1 change with mental stress was +56.0 (230) pg/mL. During follow-up, a rise of 1 standard deviation in SDF1 with mental stress was associated with a 32% higher risk for the primary endpoint of death and MI (95% confidence interval, 6%-64%), independent of the resting SDF1 level, demographic and clinical risk factors, and presence of ischemia. A rise of 1 standard deviation in SDF1 was associated with a 33% (95% confidence interval, 11%-59%) increase in the risk for the secondary endpoint, independent of the resting SDF1 level, demographic, and clinical risk factors and presence of ischemia. Conclusions: An increase in SDF1 level in response to mental stress is associated with a higher risk of adverse events in stable CAD, independent of MSIMI. Résumé: Contexte: Un stress psychologique aigu peut provoquer une ischémie myocardique induite par le stress mental chez les patients atteints d’une coronaropathie. Le facteur dérivé des cellules stromales de type 1 (SDF1) est libéré en réponse à une hypoxie, et des taux accrus de SDF1 sont associés à des résultats défavorables. Nous avons examiné si une élévation des taux de SDF1 en réponse à un stress mental permettait de prévoir la survenue de résultats défavorables chez des patients atteints d’une coronaropathie. Méthodologie: Au total, 554 patients présentant une coronaropathie stable (âge moyen de 63 ans; 76 % d’hommes; 26 % de patients de race noire) ont subi une évaluation standardisée du stress mental. Les taux plasmatiques de SDF1 ont été mesurés au repos et 90 minutes après un stress mental, et l’ischémie myocardique induite par le stress mental a été évaluée par imagerie avec injection de Tc-99m sestamibi. Les participants ont fait l’objet d’un suivi pendant cinq ans afin de surveiller la survenue des événements constituant le paramètre d’évaluation principal composé (décès et infarctus du myocarde [IM]) et le paramètre d’évaluation secondaire composé (décès, IM et hospitalisation en raison d’une insuffisance cardiaque). Des modèles de Cox ont été utilisés pour évaluer le lien entre la modification des taux de SDF1 et les événements indésirables susceptibles de survenir. Résultats: La variation moyenne du taux de SDF1 (écart-type) associée au stress mental a été de +56,0 (230) pg/ml. Pendant le suivi, une augmentation de 1 écart-type du taux de SDF1 en raison du stress mental a été associée à un risque 32 % plus élevé de survenue de l’un des événements constituant le paramètre d’évaluation principal (décès et IM) [intervalle de confiance [IC] à 95 % : 6 % à 64 %], indépendamment du taux de SDF1 au repos, des caractéristiques démographiques, des facteurs de risque clinique et de la présence d’une ischémie. Une augmentation de 1 écart-type du taux de SDF1 a été associée à un risque 33 % plus élevé (IC à 95 % : 11 % à 59 %) de survenue de l’un des événements constituant le paramètre d’évaluation secondaire, indépendamment du taux de SDF1 au repos, des caractéristiques démographiques, des facteurs de risque clinique et de la présence d’une ischémie. Conclusions: Une augmentation du taux de SDF1 en réponse à un stress mental est associée à une augmentation du risque d’événements indésirables chez les patients atteints d’une coronaropathie stable, indépendamment de la présence d’une ischémie myocardique induite par le stress mental.
- Published
- 2023
- Full Text
- View/download PDF
7. 'It's Part of the Prescription I Have to Swallow': Faculty Experience, Meaning-Making, and Role Conflict in Competency-Based Education Offered through Direct Assessment
- Author
-
Kimberly D. Pearce
- Abstract
Competency-based education that uses direct assessment in lieu of credit or clock hours as the measure of student learning is a relatively recent innovation in American higher education. Common features of these innovative programs include competency-based curriculum, authentic assessment, mastery learning, student self-pacing, federal financial aid disbursed based on student learning rather than credit hours, and disaggregated faculty roles. The first programs designed as competency-based education offered through direct assessment (CBE-DA) have been in operation since 2013. The literature on the faculty experience in these programs has been limited to faculty roles, faculty development, and the faculty's transition to competency-based education from more traditional higher education programs. The purpose of this study was to describe faculty members' experiences in direct assessment offerings and the meaning the faculty ascribe to their role. Two research questions were asked: (1) How do faculty working in direct assessment offerings describe their experiences? and (2) How do faculty make meaning of their roles in direct assessment offerings? A basic qualitative study that used symbolic interaction as its theoretical framework was designed to answer these questions. Nine faculty representing four different institutions' CBE-DA programs agreed to participate in semistructured interviews conducted through online video conferencing. Two themes emerged from data collection, analysis, and interpretation. The first theme, "Tactics," centers on how the participants described three primary design features of the CBE-DA programs in which they worked, including competency-based curriculum, faculty role disaggregation (including their roles as assessors), and self-paced learning and student affordability. The second theme, "Meaning," reflected the participants' social and professional roles as faculty; how their role in CBE-DA supported their lifestyle; how they perceived themselves as isolated, forgotten, and devalued in their CBE-DA roles; and the methods they used to take a stand for quality. The interpretation of the findings shows the faculty understand and support the goals of their CBE-DA programs and that they were drawn to their programs' innovations. However, despite their motivations and attractions to join the CBE-DA program as faculty, their actual role experience created situational identities, or identities dependent on their situation in the CBE-DA faculty role, that often contradicted the fundamental conceptualizations they held of themselves as faculty. To resolve those contradictions, the participants either left the CBE-DA assessor role or asserted their culturally anchored faculty skills to maintain their most salient identities given their situational identities within the CBE-DA program. Their skill assertions often included breaking or skirting the rules of the CBE-DA program in order to, in their minds, best serve students and the professions the students would eventually enter or in which they would advance. Findings from this research have implications for both practice and further research. Practice implications include designing more effective assessment systems, improving faculty confidence in those systems, creating fluidity or collaboration across the disaggregated faculty roles, and creating strong integrations within the enterprise. Research implications include studying the relationship between faculty identity consistency, engagement, and program performance, as well as testing the model offered on CBE-DA faculty role conflict. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]
- Published
- 2022
8. Male partners’ support and influence on pregnant women’s oral PrEP use and adherence in Malawi
- Author
-
Alinda M. Young, Friday Saidi, Twambilile Phanga, Jennifer Tseka, Agatha Bula, Pearson Mmodzi, Lisa D. Pearce, Suzanne Maman, Carol E. Golin, Wilbroad Mutale, Benjamin H. Chi, and Lauren M. Hill
- Subjects
HIV ,PrEP ,pregnant and breastfeeding women ,Malawi ,male partners ,social support ,Reproduction ,QH471-489 ,Medicine (General) ,R5-920 - Abstract
IntroductionDaily oral pre-exposure prophylaxis (PrEP) is a safe and effective HIV prevention method for pregnant and postpartum women, but adherence barriers exist. Understanding the role of male partners in supporting PrEP use may inform strategies to support PrEP adherence among pregnant and breastfeeding women.MethodsTo understand male partners’ involvement in women's use of PrEP, we conducted in-depth interviews with pregnant women in Lilongwe, Malawi who had recently decided to use PrEP (n = 30) and their male partners (n = 20) in the context of a PrEP adherence trial. Women were purposively recruited to ensure variation in their partners’ HIV status. Interviews were conducted in Chichewa using a semistructured guide. We followed a thematic approach to analyze the interview data.ResultsMost male partners were receptive to women using PrEP during pregnancy because it eased their fears of the woman and baby acquiring HIV. Men often played a key role in women's PrEP adherence by providing daily reminders and encouragement to adhere to their medication. The majority of women appreciated this support from the men as it lessened the burden of remembering to take their medications daily on their own and aided their adherence. However, several women who lacked male partner support spoke of wanting their partners to be more involved. Many men living with HIV found the mutual support beneficial for their antiretroviral therapy adherence, while men without HIV or with status unknown appreciated knowing that the family was protected. While most men were open to women continuing PrEP beyond the current study, some would only support it if women were still at risk for acquiring HIV.ConclusionIn this study, male partners were strongly motivated to support the PrEP adherence of their female partners as a way of ensuring that the pregnant women and unborn babies were protected against HIV. Promoting disclosure and tangible support that arises organically among men may be helpful, but programs to enhance this support and identify ways to support women who do not receive support from their partners or do not wish to disclose their PrEP use to partners may be needed.
- Published
- 2023
- Full Text
- View/download PDF
9. Association of systemic inflammation with posttraumatic stress disorder after a myocardial infarction
- Author
-
Peter T. Buto, Amit Shah, Brad D. Pearce, Bruno B. Lima, Zakaria Almuwaqqat, Afif Martini, Omar Al-Abboud, Nitya Tarlapally, Samaah Sullivan, Yan V. Sun, Nancy V. Murrah, Emily Driggers, Lucy Shallenberger, Tené T. Lewis, Lisa Elon, J. Douglas Bremner, Paolo Raggi, Arshed Quyyumi, and Viola Vaccarino
- Subjects
Posttraumatic stress disorder ,Myocardial infarction ,Inflammation ,Longitudinal study ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
Background: Adverse mental health conditions including depression, posttraumatic stress disorder (PTSD), and anxiety are prevalent among patients who survive myocardial infarctions (MI) and are associated with adverse outcomes. The mechanisms underlying these associations, however, are not well understood. Inflammatory pathways may mediate the cardiovascular outcomes of patients with mental health disorders. We examined the bidirectional association between PTSD symptoms and inflammatory biomarkers in a young/middle-aged post MI population. We further examined how this association may differ between women and men as well as between Black and non-Black individuals. Methods: Participants included individuals with early onset MI between the ages 25 and 60. Mental health scores for depression, PTSD, perceived stress, and anxiety as well as inflammatory biomarkers, interleukin-6 (IL-6) and high sensitivity C-reactive protein (hsCRP), were collected at baseline and at six-month follow up. We examined the bidirectional changes in mental health symptoms and inflammatory biomarkers between baseline and follow-up. Results: Among 244 patients in the study (mean age: 50.8, 48.4% female, 64.3% Black), the geometric means for IL-6 level and hsCRP at rest were 1.7 pg/mL and 2.76 mg/L, respectively. Mental health scores at baseline did not consistently predict changes in inflammatory biomarkers at follow-up. However, baseline levels of both IL-6 and hsCRP were robustly associated with an increase in re-experiencing PTSD symptoms at 6 months: in adjusted linear mixed models, there was a 1.58-point increase in re-experiencing PTSD symptoms per unit of baseline hsCRP (p = 0.01) and 2.59-point increase per unit of baseline IL-6 (p = 0.02). Once the analysis was stratified by race, the association was only noted in Black individuals. Baseline inflammation was not associated with change in any of the other mental health symptom scores. Conclusion: Markers of inflammation are associated with an increase in post-event PTSD symptoms in younger or middle-aged patients who experienced an MI, especially Black patients. These results suggest a mechanistic link between inflammation and the development of PTSD among individuals with cardiovascular disease.
- Published
- 2023
- Full Text
- View/download PDF
10. Dietary emulsifier consumption alters gene expression in the amygdala and paraventricular nucleus of the hypothalamus in mice
- Author
-
Amanda R. Arnold, Benoit Chassaing, Bradley D. Pearce, and Kim L. Huhman
- Subjects
Medicine ,Science - Abstract
Abstract Dietary emulsifier consumption promotes systemic low-grade inflammation, metabolic deregulation, and possibly an anxiety-like phenotype. The latter finding suggests that dietary emulsifiers impact brain areas that modulate stress responses. The goal of the current study was to test whether emulsifier consumption is associated with changes in gene expression in the amygdala and the paraventricular nucleus of the hypothalamus (PVN), two brain areas that are involved in behavioral and neuroendocrine responses to stress. Using RNA-Seq, we compared groups consuming either carboxymethylcellulose or polysorbate 80 for 12-weeks. A total of 243 genes were differentially expressed in the amygdala and PVN of emulsifier-treated mice compared to controls. There was minimal overlap of differentially expressed genes in CMC- and P80-treated animals, suggesting that each emulsifier acts via distinct molecular mechanisms to produce an anxiety-like phenotype. Furthermore, gene ontology and pathway analysis revealed that various stress, metabolic, and immune terms and pathways were altered by emulsifiers. These findings are the first to demonstrate that emulsifier consumption changes gene expression in brain regions that are critical for stress responding, providing possible molecular mechanisms that may underly the previously observed anxiety-like phenotype.
- Published
- 2022
- Full Text
- View/download PDF
11. Estimating Future Costs for Infrastructure in the Proposed Canadian Northern Corridor at Risk From Climate Change
- Author
-
Nathan S. Debortoli, Tristan D. Pearce, and James D. Ford
- Subjects
Political institutions and public administration (General) ,JF20-2112 - Abstract
This paper reviews current climate change projections for northern Canada and considers what these mean for infrastructure development in the proposed Canadian Northern Corridor (CNC). We focus on chokepoints along the corridor’s notional route and estimate future costs of infrastructure along the chokepoints. We draw upon climate change projections at the end of the century (2100) using information from several climate variables sourced on the CMIP6 and CMIP5 reports. Climate variables include means and extreme values for temperature, precipitation, wind and their indirect impacts on physical features: permafrost, freezing rain and wildfires. In terms of infrastructure costs, we investigate investment costs and the useful life of nine sectors within transportation, energy and buildings infrastructures. The findings of our analysis show that mean temperatures within the CNC area could increase by 10.9oC, and precipitation by 45 per cent by 2100. Climate change could create chokepoints along the CNC route, affecting key areas essential for transportation flow. Central regions of the corridor are projected to have a higher probability of receiving concomitant impacts on several chokepoints, including combined threats from the increasing frequency of wildfires, freezing rain and permafrost thaw. Adding a climatic layer to investment costs within CNC chokepoints can increase infrastructure costs by more than 101 per cent. Transportation engineering infrastructure, electric power infrastructure and the institutional buildings sectors are most likely to be impacted. Just considering a climate layer to current infrastructure increases costs by more than $12 billion for several hazards such as freezing precipitation (especially Alberta and BC), $7 billion for wildfires (especially BC) and more than $400 million for permafrost (especially Alberta and BC). Infrastructure built along the CNC route will need to be designed to remain functional under different climatic conditions that predominate today. Chokepoints will dictate how buildings and transportation infrastructure should be planned.
- Published
- 2023
- Full Text
- View/download PDF
12. Astrometric Accelerations as Dynamical Beacons: A Giant Planet Imaged inside the Debris Disk of the Young Star AF Lep
- Author
-
Kyle Franson, Brendan P. Bowler, Yifan Zhou, Tim D. Pearce, Daniella C. Bardalez Gagliuffi, Lauren I. Biddle, Timothy D. Brandt, Justin R. Crepp, Trent J. Dupuy, Jacqueline Faherty, Rebecca Jensen-Clem, Marvin Morgan, Aniket Sanghi, Christopher A. Theissen, Quang H. Tran, and Trevor N. Wolf
- Subjects
Extrasolar gaseous giant planets ,Astrometric exoplanet detection ,Direct imaging ,Orbit determination ,Debris disks ,Astrophysics ,QB460-466 - Abstract
We present the direct-imaging discovery of a giant planet orbiting the young star AF Lep, a 1.2 M _⊙ member of the 24 ± 3 Myr β Pic moving group. AF Lep was observed as part of our ongoing high-contrast imaging program targeting stars with astrometric accelerations between Hipparcos and Gaia that indicate the presence of substellar companions. Keck/NIRC2 observations in $L^{\prime} $ with the vector vortex coronagraph reveal a point source, AF Lep b, at ≈340 mas, which exhibits orbital motion at the 6 σ level over the course of 13 months. A joint orbit fit yields precise constraints on the planet’s dynamical mass of ${3.2}_{-0.6}^{+0.7}$ M _Jup , semimajor axis of ${8.4}_{-1.3}^{+1.1}$ au, and eccentricity of ${0.24}_{-0.15}^{+0.27}$ . AF Lep hosts a debris disk located at ∼50 au, but it is unlikely to be sculpted by AF Lep b, implying there may be additional planets in the system at wider separations. The stellar inclination ( i _* = ${54}_{-9}^{{+11}^\circ} $ ) and orbital inclination ( i _o = ${50}_{-12}^{{+9}^\circ} $ ) are in good agreement, which is consistent with the system having spin–orbit alignment. AF Lep b is the lowest-mass imaged planet with a dynamical mass measurement and highlights the promise of using astrometric accelerations as a tool to find and characterize long-period planets.
- Published
- 2023
- Full Text
- View/download PDF
13. Association of COVID-19 pandemic-related concern and health routine changes with functioning among individuals with systemic lupus erythematosus
- Author
-
S Sam Lim, Cristina Drenkard, Charmayne Dunlop-Thomas, Laura C Plantinga, C Barrett Bowling, Courtney Hoge, and Brad D Pearce
- Subjects
Immunologic diseases. Allergy ,RC581-607 - Abstract
Objective To examine whether pandemic-related issues were associated with physical functioning, community mobility and cognition among individuals with SLE.Methods Participants were recruited (6 October 2020–11 November 2021) for this cross-sectional study from a population-based cohort of individuals with validated SLE in metropolitan Atlanta, as part of an ongoing ancillary study. Pandemic-related issues (concern about the pandemic (very vs somewhat/not at all concerned); changes in physical activity and sleep (less vs more/same); difficulty obtaining food and medications and accessing routine care (any vs none)) were self-reported. Self-reported physical functioning and episodic and working memory performance were reported as t-scores (such that a score of 50=population mean and a 10-point difference=1 SD) and community mobility scores ranged from 0 to 120, with higher scores representing better functioning for all domains. Differences in scores were assessed via t-tests and age-adjusted, sex-adjusted and race-adjusted linear regression.Results Among 245 participants (mean age, 46 years; 95% female, 77% black), physical functioning t-scores (mean=44) were consistently lower (by 3–5 points) for those who reported concern about the pandemic, less physical activity and sleep, difficulty obtaining food and medications, and accessing routine care. Similarly, community mobility scores (mean=48) were lower (by 10–20 points) for these individuals. There were no substantial differences in episodic memory and working memory t-scores (mean=50 and 47, respectively) by pandemic-related issues.Conclusion We found that physical functioning and community mobility, but not cognition, were lower among those who reported more concern about the pandemic or greater disruptions to health routines. Future studies should explore interventions among these vulnerable individuals with SLE, who already disproportionately suffer from functional impairment, to maintain functioning and prevent adverse outcomes during times of crisis.
- Published
- 2022
- Full Text
- View/download PDF
14. Non-invasive vagal nerve stimulation decreases brain activity during trauma scripts
- Author
-
Matthew T. Wittbrodt, Nil Z. Gurel, Jonathon A. Nye, Stacy Ladd, Md Mobashir H. Shandhi, Minxuan Huang, Amit J. Shah, Bradley D. Pearce, Zuhayr S. Alam, Mark H. Rapaport, Nancy Murrah, Yi-An Ko, Ammer A. Haffer, Lucy H. Shallenberger, Viola Vaccarino, Omer T. Inan, and J. Douglas Bremner
- Subjects
Vagal nerve stimulation ,PTSD ,Trauma scripts ,Stress ,Prefrontal cortex ,Insula ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
Background: Traumatic stress can have lasting effects on neurobiology and result in psychiatric conditions such as posttraumatic stress disorder (PTSD). We hypothesize that non-invasive cervical vagal nerve stimulation (nVNS) may alleviate trauma symptoms by reducing stress sympathetic reactivity. This study examined how nVNS alters neural responses to personalized traumatic scripts. Methods: Nineteen participants who had experienced trauma but did not have the diagnosis of PTSD completed this double-blind sham-controlled study. In three sequential time blocks, personalized traumatic scripts were presented to participants immediately followed by either sham stimulation (n = 8; 0–14 V, 0.2 Hz, pulse width = 5s) or active nVNS (n = 11; 0–30 V, 25 Hz, pulse width = 40 ms). Brain activity during traumatic scripts was assessed using High Resolution Positron Emission Tomography (HR-PET) with radiolabeled water to measure brain blood flow. Results: Traumatic scripts resulted in significant activations within the bilateral medial and orbital prefrontal cortex, premotor cortex, anterior cingulate, thalamus, insula, hippocampus, right amygdala, and right putamen. Greater activation was observed during sham stimulation compared to nVNS within the bilateral prefrontal and orbitofrontal cortex, premotor cortex, temporal lobe, parahippocampal gyrus, insula, and left anterior cingulate. During the first exposure to the trauma scripts, greater activations were found in the motor cortices and ventral visual stream whereas prefrontal cortex and anterior cingulate activations were more predominant with later script presentations for those subjects receiving sham stimulation. Conclusion: nVNS decreases neural reactivity to an emotional stressor in limbic and other brain areas involved in stress, with changes over repeated exposures suggesting a shift from scene appraisal to cognitively processing the emotional event.
- Published
- 2020
- Full Text
- View/download PDF
15. Early Life Trauma Is Associated With Increased Microvolt T‐Wave Alternans During Mental Stress Challenge: A Substudy of Mental Stress Ischemia: Prognosis and Genetic Influences
- Author
-
Amit J. Shah, Virginia Weeks, Rachel Lampert, J. Douglas Bremner, Michael Kutner, Paolo Raggi, Yan V. Sun, Tené T. Lewis, Oleksiy Levantsevych, Ye Ji Kim, Muhammad Hammadah, Ayman Alkhoder, Matthew Wittbrodt, Brad D. Pearce, Laura Ward, David Sheps, Arshed A. Quyyumi, and Viola Vaccarino
- Subjects
psychological stress ,repolarization heterogeneity ,sudden cardiac death risk ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Background Early life trauma has been associated with increased cardiovascular risk, but the arrhythmic implications are unclear. We hypothesized that in patients with coronary artery disease, early life trauma predicts increased arrhythmic risk during mental stress, measured by elevated microvolt T‐wave alternans (TWA), a measure of repolarization heterogeneity and sudden cardiac death risk. Methods and Results In a cohort with stable coronary artery disease (NCT04123197), we examined early life trauma with the Early Trauma Inventory Self Report‐Short Form. Participants underwent a laboratory‐based mental stress speech task with Holter monitoring, as well as a structured psychiatric interview. We measured TWA during rest, mental stress, and recovery with ambulatory electrocardiographic monitoring. We adjusted for sociodemographic factors, cardiac history, psychiatric comorbidity, and hemodynamic stress reactivity with multivariable linear regression models. We examined 320 participants with noise‐ and arrhythmia‐free ECGs. The mean (SD) age was 63.8 (8.7) years, 27% were women, and 27% reported significant childhood trauma (Early Trauma Inventory Self Report‐Short Form ≥10). High childhood trauma was associated with a multivariable‐adjusted 17% increase in TWA (P=0.04) during stress, and each unit increase in the Early Trauma Inventory Self Report‐Short Form total score was associated with a 1.7% higher stress TWA (P=0.02). The largest effect sizes were found with the emotional trauma subtype. Conclusions In a cohort with stable coronary artery disease, early life trauma, and in particular emotional trauma, is associated with increased TWA, a marker of increased arrhythmic risk, during mental stress. This association suggests that early trauma exposures may affect long‐term sudden cardiac death risk during emotional triggers, although more studies are warranted.
- Published
- 2022
- Full Text
- View/download PDF
16. Transcutaneous Cervical Vagal Nerve Stimulation in Patients with Posttraumatic Stress Disorder (PTSD): A Pilot Study of Effects on PTSD Symptoms and Interleukin-6 Response to Stress
- Author
-
J. Douglas Bremner, Matthew T. Wittbrodt, Nil Z. Gurel, MdMobashir H. Shandhi, Asim H. Gazi, Yunshen Jiao, Oleksiy M. Levantsevych, Minxuan Huang, Joy Beckwith, Isaias Herring, Nancy Murrah, Emily G. Driggers, Yi-An Ko, MhmtJamil L. Alkhalaf, Majd Soudan, Lucy Shallenberger, Allison N. Hankus, Jonathon A. Nye, Jeanie Park, Anna Woodbury, Puja K. Mehta, Mark H. Rapaport, Viola Vaccarino, Amit J. Shah, Bradley D. Pearce, and Omer T. Inan
- Subjects
Mental healing ,RZ400-408 - Abstract
Background: Posttraumatic stress disorder (PTSD) is a highly disabling condition associated with alterations in multiple neurobiological systems, including increases in inflammatory and sympathetic function, responsible for maintenance of symptoms. Treatment options including medications and psychotherapies have limitations. We previously showed that transcutaneous Vagus Nerve Stimulation (tcVNS) blocks inflammatory (interleukin (IL)-6) responses to stress in PTSD. The purpose of this study was to assess the effects of tcVNS on PTSD symptoms and inflammatory responses to stress. Methods: Twenty patients with PTSD were randomized to double blind active tcVNS (N=9) or sham (N=11) stimulation in conjunction with exposure to personalized traumatic scripts immediately followed by active or sham tcVNS and measurement of IL-6 and other biomarkers of inflammation. Patients then self administered active or sham tcVNS twice daily for three months. PTSD symptoms were measured with the PTSD Checklist (PCL) and the Clinician Administered PTSD Scale (CAPS), clinical improvement with the Clinical Global Index (CGI) and anxiety with the Hamilton Anxiety Scale (Ham-A) at baseline and one-month intervals followed by a repeat of measurement of biomarkers with traumatic scripts. After three months patients self treated with twice daily open label active tcVNS for another three months followed by assessment with the CGI. Results: Traumatic scripts increased IL-6 in PTSD patients, an effect that was blocked by tcVNS (p
- Published
- 2021
- Full Text
- View/download PDF
17. Polygenic risk scores differentiate schizophrenia patients with toxoplasma gondii compared to toxoplasma seronegative patients
- Author
-
Adriana Lori, Dimitrios Avramopoulos, Alex W. Wang, Jennifer Mulle, Nicholas Massa, Erica J. Duncan, Abigail Powers, Karen Conneely, Charles F. Gillespie, Tanja Jovanovic, Kerry J. Ressler, and Brad D. Pearce
- Subjects
Psychiatry ,RC435-571 - Abstract
Schizophrenia (SCZ) is an etiologically heterogeneous disease with genetic and environmental risk factors (e.g., Toxoplasma gondii infection) differing among affected individuals. Distinguishing such risk factors may point to differences in pathophysiological pathways and facilitate the discovery of individualized treatments. Toxoplasma gondii (TOXO) has been implicated in increasing the risk of schizophrenia. To determine whether TOXO-positive individuals with SCZ have a different polygenic risk burden than uninfected people, we applied the SCZ polygenic risk score (SCZ-PRS) derived from the Psychiatric GWAS Consortium separately to the TOXO-positive and TOXO-negative subjects with the diagnosis of SCZ as the outcome variable. The SCZ-PRS does not include variants in the major histocompatibility complex.Of 790 subjects assessed for TOXO, the 662 TOXO-negative subjects (50.8% with SCZ) reached a Bonferroni corrected significant association (p = 0.00017, R2 = 0.023). In contrast, the 128 TOXO-positive individuals (53.1% with SCZ) showed no significant association (p = 0.354) for SCZ-PRS and had a much lower R2 (R2 = 0.007). To account for Type-2 error in the TOXO-positive dataset, we performed a random sampling of the TOXO-negative subpopulation (n = 130, repeated 100 times) to simulate equivalent power between groups: the p-value was 0.354.We found intriguing evidence that the SCZ-PRS predicts SCZ in TOXO-negative subjects, as expected, but not in the TOXO-positive individuals. This result highlights the importance of considering environmental risk factors to distinguish a subgroup with independent or different genetic components involved in the development of SCZ.
- Published
- 2021
- Full Text
- View/download PDF
18. Vaginal Microbiome Composition in Early Pregnancy and Risk of Spontaneous Preterm and Early Term Birth Among African American Women
- Author
-
Anne L. Dunlop, Glen A. Satten, Yi-Juan Hu, Anna K. Knight, Cherie C. Hill, Michelle L. Wright, Alicia K. Smith, Timothy D. Read, Bradley D. Pearce, and Elizabeth J. Corwin
- Subjects
microbiome ,microbiota ,pregnancy ,preterm birth ,early term birth ,gestational age at birth ,Microbiology ,QR1-502 - Abstract
ObjectiveTo evaluate the association between the early pregnancy vaginal microbiome and spontaneous preterm birth (sPTB) and early term birth (sETB) among African American women.MethodsVaginal samples collected in early pregnancy (8-14 weeks’ gestation) from 436 women enrolled in the Emory University African American Vaginal, Oral, and Gut Microbiome in Pregnancy Study underwent 16S rRNA gene sequencing of the V3-V4 region, taxonomic classification, and community state type (CST) assignment. We compared vaginal CST and abundance of taxa for women whose pregnancy ended in sPTB (N = 44) or sETB (N= 84) to those who delivered full term (N = 231).ResultsNearly half of the women had a vaginal microbiome classified as CST IV (Diverse CST), while one-third had CST III (L. iners dominated) and just 16% had CST I, II, or V (non-iners Lactobacillus dominated). Compared to vaginal CST I, II, or V (non-iners Lactobacillus dominated), both CST III (L. iners dominated) and CST IV (Diverse) were associated with sPTB with an adjusted odds ratio (95% confidence interval) of 4.1 (1.1, infinity) and 7.7 (2.2, infinity), respectively, in multivariate logistic regression. In contrast, no vaginal CST was associated with sETB. The linear decomposition model (LDM) based on amplicon sequence variant (ASV) relative abundance found a significant overall effect of the vaginal microbiome on sPTB (p=0.034) but not sETB (p=0.320), whereas the LDM based on presence/absence of ASV found no overall effect on sPTB (p=0.328) but a significant effect on sETB (p=0.030). In testing for ASV-specific effects, the LDM found that no ASV was significantly associated with sPTB considering either relative abundance or presence/absence data after controlling for multiple comparisons (FDR 10%), although in marginal analysis the relative abundance of Gardnerella vaginalis (p=0.011), non-iners Lactobacillus (p=0.016), and Mobiluncus curtisii (p=0.035) and the presence of Atopobium vaginae (p=0.049), BVAB2 (p=0.024), Dialister microaerophilis (p=0.011), and Prevotella amnii (p=0.044) were associated with sPTB. The LDM identified the higher abundance of 7 ASVs and the presence of 13 ASVs, all commonly residents of the gut, as associated with sETB at FDR < 10%.ConclusionsIn this cohort of African American women, an early pregnancy vaginal CST III or IV was associated with an increased risk of sPTB but not sETB. The relative abundance and presence of distinct taxa within the early pregnancy vaginal microbiome was associated with either sPTB or sETB.
- Published
- 2021
- Full Text
- View/download PDF
19. p-GROUPS WITH CYCLIC OR GENERALISED QUATERNION HUGHES SUBGROUPS: CLASSIFYING TIDY p-GROUPS
- Author
-
NICOLAS F. BEIKE, RACHEL CARLETON, DAVID G. COSTANZO, COLIN HEATH, MARK L. LEWIS, KAIWEN LU, and JAMIE D. PEARCE
- Subjects
General Mathematics - Abstract
Let G be a p-group for some prime p. Recall that the Hughes subgroup of G is the subgroup generated by all of the elements of G with order not equal to p. In this paper, we prove that if the Hughes subgroup of G is cyclic, then G has exponent p or is cyclic or is dihedral. We also prove that if the Hughes subgroup of G is generalised quaternion, then G must be generalised quaternion. With these results in hand, we classify the tidy p-groups.
- Published
- 2023
- Full Text
- View/download PDF
20. One Hundred Years of Religion in Social Forces
- Author
-
Lisa D Pearce
- Subjects
History ,Sociology and Political Science ,Anthropology - Published
- 2023
- Full Text
- View/download PDF
21. Transcutaneous vagal nerve stimulation blocks stress-induced activation of Interleukin-6 and interferon-γ in posttraumatic stress disorder: A double-blind, randomized, sham-controlled trial
- Author
-
J. Douglas Bremner, Nil Z. Gurel, Yunshen Jiao, Matthew T. Wittbrodt, Oleksiy M. Levantsevych, Minxuan Huang, Hewon Jung, MdMobashir H. Shandhi, Joy Beckwith, Isaias Herring, Mark H. Rapaport, Nancy Murrah, Emily Driggers, Yi-An Ko, MhmtJamil L. Alkhalaf, Majd Soudan, Jiawei Song, Benson S. Ku, Lucy Shallenberger, Allison N. Hankus, Jonathon A. Nye, Jeanie Park, Viola Vaccarino, Amit J. Shah, Omer T. Inan, and Bradley D. Pearce
- Subjects
Stress disorders, posttraumatic ,Vagus nerve ,Inflammation ,Interleukin-6 ,PTSD ,Interferon ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
Posttraumatic stress disorder (PTSD) is a highly disabling condition associated with alterations in multiple neurobiological systems, including increases in inflammatory function. Vagus nerve stimulation (VNS) decreases inflammation, however few studies have examined the effects of non-invasive VNS on physiology in human subjects, and no studies in patients with PTSD. The purpose of this study was to assess the effects of transcutaneous cervical VNS (tcVNS) on inflammatory responses to stress. Thirty subjects with a history of exposure to traumatic stress with (N = 10) and without (N = 20) PTSD underwent exposure to stressful tasks immediately followed by active or sham tcVNS and measurement of multiple biomarkers of inflammation (interleukin-(IL)-6, IL-2, IL-1β, Tumor Necrosis Factor alpha (TNFα) and Interferon gamma (IFNγ) over multiple time points. Stressful tasks included exposure to personalized scripts of traumatic events on day 1, and public speech and mental arithmetic (Mental Stress) tasks on days 2 and 3. Traumatic scripts were associated with a pattern of subjective anger measured with Visual Analogue Scales and increased IL-6 and IFNγ in PTSD patients that was blocked by tcVNS (p
- Published
- 2020
- Full Text
- View/download PDF
22. Toxoplasma gondii Effects on the Relationship of Kynurenine Pathway Metabolites to Acoustic Startle Latency in Schizophrenia vs. Control Subjects
- Author
-
Bradley D. Pearce, Nicholas Massa, David R. Goldsmith, Zeal H. Gandhi, Allison Hankus, Alaaeddin Alrohaibani, Neha Goel, Bruce Cuthbert, Molly Fargotstein, Dana Boyd Barr, Parinya Panuwet, Victoria M. Brown, and Erica Duncan
- Subjects
schizophrenia ,acoustic startle ,Toxoplasma gondii ,kynurenines ,startle latency ,tryptophan ,Psychiatry ,RC435-571 - Abstract
Background: Chronic infection with Toxoplasma gondii (TOXO) results in microcysts in the brain that are controlled by inflammatory activation and subsequent changes in the kynurenine pathway. TOXO seropositivity is associated with a heightened risk of schizophrenia (SCZ) and with cognitive impairments. Latency of the acoustic startle response, a putative index of neural processing speed, is slower in SCZ. SCZ subjects who are TOXO seropositive have slower latency than SCZ subjects who are TOXO seronegative. We assessed the relationship between kynurenine pathway metabolites and startle latency as a potential route by which chronic TOXO infection can lead to cognitive slowing in SCZ.Methods: Fourty-seven SCZ subjects and 30 controls (CON) were tested on a standard acoustic startle paradigm. Kynurenine pathway metabolites were measured using liquid chromatography-tandem mass spectrometry were kynurenine (KYN), tryptophan (TRYP), 3-hydroxyanthranilic acid (3-OHAA), anthranilic acid (AA), and kynurenic acid (KYNA). TOXO status was determined by IgG ELISA.Results: In univariate ANCOVAs on onset and peak latency with age and log transformed startle magnitude as covariates, both onset latency [F(1,61) = 5.76; p = 0.019] and peak latency [F(1,61) = 4.34; p = 0.041] were slower in SCZ than CON subjects. In stepwise backward linear regressions after stratification by Diagnosis, slower onset latency in SCZ subjects was predicted by higher TRYP (B = 0.42; p = 0.008) and 3-OHAA:AA (B = 3.68; p = 0.007), and lower KYN:TRYP (B = −185.42; p = 0.034). In regressions with peak latency as the dependent variable, slower peak latency was predicted by higher TRYP (B = 0.47; p = 0.013) and 3-OHAA:AA ratio (B = 4.35; p = 0.010), and by lower KYNA (B = −6.67; p = 0.036). In CON subjects neither onset nor peak latency was predicted by any KYN metabolites. In regressions stratified by TOXO status, in TOXO positive subjects, slower peak latency was predicted by lower concentrations of KYN (B = −8.08; p = 0.008), KYNA (B = −10.64; p = 0.003), and lower KYN:TRYP ratios (B = −347.01; p = 0.03). In TOXO negative subjects neither onset nor peak latency was predicted by any KYN metabolites.Conclusions: KYN pathway markers predict slowing of startle latency in SCZ subjects and in those with chronic TOXO infection, but this is not seen in CON subjects nor TOXO seronegative subjects. These findings coupled with prior work indicating a relationship of slower latency with SCZ and TOXO infection suggest that alterations in KYN pathway markers may be a mechanism by which neural processing speed, as indexed by startle latency, is affected in these subjects.
- Published
- 2020
- Full Text
- View/download PDF
23. Effect of transcutaneous cervical vagus nerve stimulation on the pituitary adenylate cyclase-activating polypeptide (PACAP) response to stress: A randomized, sham controlled, double blind pilot study
- Author
-
Nil Z. Gurel, Yunshen Jiao, Matthew T. Wittbrodt, Yi-An Ko, Allison Hankus, Emily G. Driggers, Stacy L. Ladd, Lucy Shallenberger, Nancy Murrah, Minxuan Huang, Ammer Haffar, Mhmtjamil Alkhalaf, Oleksiy Levantsevych, Jonathon A. Nye, Viola Vaccarino, Amit J. Shah, Omer T. Inan, J. Douglas Bremner, and Bradley D. Pearce
- Subjects
Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 ,Psychology ,BF1-990 - Abstract
Pituitary adenylate cyclase-activating peptide (PACAP) is a neuropeptide that plays a key role in the neurobiology of the stress response, and prior studies suggest that its function is dysregulated in post-traumatic stress disorder (PTSD). Transcutaneous cervical vagus nerve stimulation (tcVNS) acts through PACAP and other neurobiological systems to modulate stress responses and/or symptoms of PTSD. In this pilot study, we examined the effects of tcVNS on PACAP in a three day chronic stress laboratory paradigm involving serial traumatic and mental stress exposures in healthy individuals with a history of exposure to psychological trauma (n = 18) and patients with PTSD (n = 12). Methods: A total of 30 subjects with a history of exposure to psychological trauma experience were recruited (12 with PTSD diagnosis) for a three-day randomized double-blinded study of tcVNS or sham stimulation. Subjects underwent a protocol that included both personalized trauma recall and non-personalized mental stressors (public speaking, mental arithmetic) paired to tcVNS or sham stimulation over three days. Blood was collected at baseline and multiple time points after exposure to stressors. Linear mixed-effects models were used to assess changes in PACAP over time (in response to stressors) and its relation to active tcVNS or sham stimulation. Results: PACAP blood levels increased over the course of three days for both active tcVNS and sham groups. This increase was statistically-significant in the sham group at the end of the second (Cohen’s drm = 0.35, p = 0.04), and third days (drm = 0.41, p = 0.04), but not in the active tcVNS group (drm = 0.21, drm = 0.18, and p > 0.20). Conclusion: These pilot findings suggest tcVNS may attenuate this neurobiological stress-response. Larger studies are needed to investigate gender and interaction effects.
- Published
- 2020
- Full Text
- View/download PDF
24. Transcutaneous cervical vagal nerve stimulation reduces sympathetic responses to stress in posttraumatic stress disorder: A double-blind, randomized, sham controlled trial
- Author
-
Nil Z. Gurel, Matthew T. Wittbrodt, Hewon Jung, Md. Mobashir H. Shandhi, Emily G. Driggers, Stacy L. Ladd, Minxuan Huang, Yi-An Ko, Lucy Shallenberger, Joy Beckwith, Jonathon A. Nye, Bradley D. Pearce, Viola Vaccarino, Amit J. Shah, Omer T. Inan, and J. Douglas Bremner
- Subjects
Posttraumatic stress disorder ,Wearable bioelectronic medicine ,Vagus nerve stimulation ,Transcutaneous cervical stimulation ,Stress ,Electroceuticals ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 ,Neurology. Diseases of the nervous system ,RC346-429 ,Neurophysiology and neuropsychology ,QP351-495 - Abstract
Objective: Exacerbated autonomic responses to acute stress are prevalent in posttraumatic stress disorder (PTSD). The purpose of this study was to assess the effects of transcutaneous cervical VNS (tcVNS) on autonomic responses to acute stress in patients with PTSD. The authors hypothesized tcVNS would reduce the sympathetic response to stress compared to a sham device. Methods: Using a randomized double-blind approach, we studied the effects of tcVNS on physiological responses to stress in patients with PTSD (n = 25) using noninvasive sensing modalities. Participants received either sham (n = 12) or active tcVNS (n = 13) after exposure to acute personalized traumatic script stress and mental stress (public speech, mental arithmetic) over a three-day protocol. Physiological parameters related to sympathetic responses to stress were investigated. Results: Relative to sham, tcVNS paired to traumatic script stress decreased sympathetic function as measured by: decreased heart rate (adjusted β = −5.7%; 95% CI: ±3.6%, effect size d = 0.43, p
- Published
- 2020
- Full Text
- View/download PDF
25. Detailed Characterization and Monitoring of a Retrogressive Thaw Slump from Remotely Piloted Aircraft Systems and Identifying Associated Influence on Carbon and Nitrogen Export.
- Author
-
Kevin W. Turner, Michelle D. Pearce, and Daniel D. Hughes
- Published
- 2021
- Full Text
- View/download PDF
26. A multi-decade record of high-quality fCO2 data in version 3 of the Surface Ocean CO2 Atlas (SOCAT)
- Author
-
D. C. E. Bakker, B. Pfeil, C. S. Landa, N. Metzl, K. M. O'Brien, A. Olsen, K. Smith, C. Cosca, S. Harasawa, S. D. Jones, S.-I. Nakaoka, Y. Nojiri, U. Schuster, T. Steinhoff, C. Sweeney, T. Takahashi, B. Tilbrook, C. Wada, R. Wanninkhof, S. R. Alin, C. F. Balestrini, L. Barbero, N. R. Bates, A. A. Bianchi, F. Bonou, J. Boutin, Y. Bozec, E. F. Burger, W.-J. Cai, R. D. Castle, L. Chen, M. Chierici, K. Currie, W. Evans, C. Featherstone, R. A. Feely, A. Fransson, C. Goyet, N. Greenwood, L. Gregor, S. Hankin, N. J. Hardman-Mountford, J. Harlay, J. Hauck, M. Hoppema, M. P. Humphreys, C. W. Hunt, B. Huss, J. S. P. Ibánhez, T. Johannessen, R. Keeling, V. Kitidis, A. Körtzinger, A. Kozyr, E. Krasakopoulou, A. Kuwata, P. Landschützer, S. K. Lauvset, N. Lefèvre, C. Lo Monaco, A. Manke, J. T. Mathis, L. Merlivat, F. J. Millero, P. M. S. Monteiro, D. R. Munro, A. Murata, T. Newberger, A. M. Omar, T. Ono, K. Paterson, D. Pearce, D. Pierrot, L. L. Robbins, S. Saito, J. Salisbury, R. Schlitzer, B. Schneider, R. Schweitzer, R. Sieger, I. Skjelvan, K. F. Sullivan, S. C. Sutherland, A. J. Sutton, K. Tadokoro, M. Telszewski, M. Tuma, S. M. A. C. van Heuven, D. Vandemark, B. Ward, A. J. Watson, and S. Xu
- Subjects
Environmental sciences ,GE1-350 ,Geology ,QE1-996.5 - Abstract
The Surface Ocean CO2 Atlas (SOCAT) is a synthesis of quality-controlled fCO2 (fugacity of carbon dioxide) values for the global surface oceans and coastal seas with regular updates. Version 3 of SOCAT has 14.7 million fCO2 values from 3646 data sets covering the years 1957 to 2014. This latest version has an additional 4.6 million fCO2 values relative to version 2 and extends the record from 2011 to 2014. Version 3 also significantly increases the data availability for 2005 to 2013. SOCAT has an average of approximately 1.2 million surface water fCO2 values per year for the years 2006 to 2012. Quality and documentation of the data has improved. A new feature is the data set quality control (QC) flag of E for data from alternative sensors and platforms. The accuracy of surface water fCO2 has been defined for all data set QC flags. Automated range checking has been carried out for all data sets during their upload into SOCAT. The upgrade of the interactive Data Set Viewer (previously known as the Cruise Data Viewer) allows better interrogation of the SOCAT data collection and rapid creation of high-quality figures for scientific presentations. Automated data upload has been launched for version 4 and will enable more frequent SOCAT releases in the future. High-profile scientific applications of SOCAT include quantification of the ocean sink for atmospheric carbon dioxide and its long-term variation, detection of ocean acidification, as well as evaluation of coupled-climate and ocean-only biogeochemical models. Users of SOCAT data products are urged to acknowledge the contribution of data providers, as stated in the SOCAT Fair Data Use Statement. This ESSD (Earth System Science Data) "living data" publication documents the methods and data sets used for the assembly of this new version of the SOCAT data collection and compares these with those used for earlier versions of the data collection (Pfeil et al., 2013; Sabine et al., 2013; Bakker et al., 2014). Individual data set files, included in the synthesis product, can be downloaded here: doi:10.1594/PANGAEA.849770. The gridded products are available here: doi:10.3334/CDIAC/OTG.SOCAT_V3_GRID.
- Published
- 2016
- Full Text
- View/download PDF
27. The clumpy structure of $\epsilon$ Eridani's debris disc revisited by ALMA
- Author
-
Mark Booth, Tim D Pearce, Alexander V Krivov, Mark C Wyatt, William R F Dent, Antonio S Hales, Jean-François Lestrade, Fernando Cruz-Sáenz de Miera, Virginie C Faramaz, Torsten Löhne, and Miguel Chavez-Dagostino
- Subjects
Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,Astronomy and Astrophysics ,Astrophysics - Earth and Planetary Astrophysics - Abstract
$\epsilon$ Eridani is the closest star to our Sun known to host a debris disc. Prior observations in the (sub-)millimetre regime have potentially detected clumpy structure in the disc and attributed this to interactions with an (as yet) undetected planet. However, the prior observations were unable to distinguish between structure in the disc and background confusion. Here we present the first ALMA image of the entire disc, which has a resolution of 1.6"$\times$1.2". We clearly detect the star, the main belt and two point sources. The resolution and sensitivity of this data allow us to clearly distinguish background galaxies (that show up as point sources) from the disc emission. We show that the two point sources are consistent with background galaxies. After taking account of these, we find that resolved residuals are still present in the main belt, including two clumps with a $>3\sigma$ significance -- one to the east of the star and the other to the northwest. We perform $n$-body simulations to demonstrate that a migrating planet can form structures similar to those observed by trapping planetesimals in resonances. We find that the observed features can be reproduced by a migrating planet trapping planetesimals in the 2:1 mean motion resonance and the symmetry of the most prominent clumps means that the planet should have a position angle of either ${\sim10^\circ}$ or ${\sim190^\circ}$. Observations over multiple epochs are necessary to test whether the observed features rotate around the star., Comment: 16 pages, 10 figures, accepted for publication in MNRAS
- Published
- 2023
28. The Making of African Policy in the Colonial Office, 1945-48: The End of Indirect Rule and the Planning of Local Government
- Author
-
R. D. Pearce
- Published
- 2023
- Full Text
- View/download PDF
29. Lord Hailey and Colonial Office Thought on African Policy
- Author
-
R. D. Pearce
- Published
- 2023
- Full Text
- View/download PDF
30. The Re-definition of Imperial Principles in International and National Politics
- Author
-
R. D. Pearce
- Published
- 2023
- Full Text
- View/download PDF
31. Creech Jones and the Labour Government's Imperial Attitudes and Impact
- Author
-
R. D. Pearce
- Published
- 2023
- Full Text
- View/download PDF
32. Reform at the Centre Overtakes Reform in Local Government
- Author
-
R. D. Pearce
- Published
- 2023
- Full Text
- View/download PDF
33. Conclusion
- Author
-
R. D. Pearce
- Published
- 2023
- Full Text
- View/download PDF
34. Introduction
- Author
-
R. D. Pearce
- Published
- 2023
- Full Text
- View/download PDF
35. Planning the Transfer of Power
- Author
-
R. D. Pearce
- Published
- 2023
- Full Text
- View/download PDF
36. African Governors and the Making of Policy in Africa
- Author
-
R. D. Pearce
- Published
- 2023
- Full Text
- View/download PDF
37. Comparison of autonomic stress reactivity in young healthy versus aging subjects with heart disease.
- Author
-
Nil Z Gurel, Andrew M Carek, Omer T Inan, Oleksiy Levantsevych, Naser Abdelhadi, Muhammad Hammadah, Wesley T O'Neal, Heval Kelli, Kobina Wilmot, Laura Ward, Steven Rhodes, Brad D Pearce, Puja K Mehta, Michael Kutner, Ernest Garcia, Arshed Quyyumi, Viola Vaccarino, Paolo Raggi, J Douglas Bremner, and Amit J Shah
- Subjects
Medicine ,Science - Abstract
BackgroundThe autonomic response to acute emotional stress can be highly variable, and pathological responses are associated with increased risk of adverse cardiovascular events. We evaluated the autonomic response to stress reactivity of young healthy subjects and aging subjects with coronary artery disease to understand how the autonomic stress response differs with aging.MethodsPhysiologic reactivity to arithmetic stress in a cohort of 25 young, healthy subjects (< 30 years) and another cohort of 25 older subjects (> 55 years) with CAD was evaluated using electrocardiography, impedance cardiography, and arterial pressure recordings. Stress-related changes in the pre-ejection period (PEP), which measures sympathetic activity, and high frequency heart rate variability (HF HRV), which measures parasympathetic activity, were analyzed as primary outcomes.ResultsMental stress reduced PEP in both groups (pDiscussionPEP decreases with stress regardless of health and age status, implying increased sympathetic function. Its decline with stress may be attenuated in CAD. The HF HRV (parasympathetic) stress reactivity is more variable and attenuated in younger individuals; perhaps this is related to a protective parasympathetic reflex.Trial registrationClinicalTrials.gov Identifier: NCT02657382.
- Published
- 2019
- Full Text
- View/download PDF
38. Young Women With Coronary Artery Disease Exhibit Higher Concentrations of Interleukin‐6 at Baseline and in Response to Mental Stress
- Author
-
Samaah Sullivan, Muhammad Hammadah, Kobina Wilmot, Ronnie Ramadan, Brad D. Pearce, Amit Shah, Belal Kaseer, Mohamad Mazen Gafeer, Bruno B. Lima, Jeong Hwan Kim, Laura Ward, Yi‐An Ko, Tené T. Lewis, Allison Hankus, Lisa Elon, Lian Li, J. Douglas Bremner, Paolo Raggi, Arshed Quyyumi, and Viola Vaccarino
- Subjects
inflammation ,interleukin ,mental stress ,stress test ,women ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
Background Young women with coronary artery disease (CAD), a group with high psychosocial burden, were previously shown to have higher levels of interleukin‐6 (IL‐6) compared with men of similar age. We sought to examine IL‐6 response to acute stress in CAD patients across sex and age, and contrast results to healthy controls and other biomarkers known to increase with mental stress (monocyte chemoattractant protein‐1 and matrix metallopeptidase‐9) and known limited stress‐reactivity (high‐sensitivity C‐reactive protein). Methods and Results Inflammatory biomarkers were measured at rest and 90 minutes after mental stress (speech task) among 819 patients with CAD and 89 healthy controls. Repeated‐measures models were used to investigate age (continuous) and sex differences across time, before and after adjusting for demographics, CAD risk factors, depressive symptoms, medication use, and CAD severity. Among patients with CAD, the mean age was 60 years (range, 25–79) and 31% were women. Younger women with CAD had significantly higher concentrations of IL‐6 at rest, 90 minutes after mental stress, as well as a higher response to stress, compared with similarly aged men (P
- Published
- 2018
- Full Text
- View/download PDF
39. Myocardial Ischemia and Mobilization of Circulating Progenitor Cells
- Author
-
Muhammad Hammadah, Ayman Samman Tahhan, Ibhar Al Mheid, Kobina Wilmot, Ronnie Ramadan, Bryan R. Kindya, Heval M. Kelli, Wesley T. O'Neal, Pratik Sandesara, Samaah Sullivan, Zakaria Almuwaqqat, Malik Obideen, Naser Abdelhadi, Ayman Alkhoder, Pratik M. Pimple, Oleksiy Levantsevych, Kareem H. Mohammed, Lei Weng, Laurence S. Sperling, Amit J. Shah, Yan V. Sun, Brad D. Pearce, Michael Kutner, Laura Ward, J. Douglas Bremner, Jinhee Kim, Edmund K. Waller, Paolo Raggi, David Sheps, Viola Vaccarino, and Arshed A. Quyyumi
- Subjects
coexpression of chemokine receptor 4 ,ischemia ,progenitor cell ,stromal‐derived factor ,vascular endothelial growth factor ,Diseases of the circulatory (Cardiovascular) system ,RC666-701 - Abstract
BackgroundThe response of progenitor cells (PCs) to transient myocardial ischemia in patients with coronary artery disease remains unknown. We aimed to investigate the PC response to exercise‐induced myocardial ischemia (ExMI) and compare it to flow mismatch during pharmacological stress testing. Methods and ResultsA total of 356 patients with stable coronary artery disease underwent 99mTc‐sestamibi myocardial perfusion imaging during exercise (69%) or pharmacological stress (31%). CD34+ and CD34+/chemokine (C‐X‐C motif) receptor 4 PCs were enumerated by flow cytometry. Change in PC count was compared between patients with and without myocardial ischemia using linear regression models. Vascular endothelial growth factor and stromal‐derived factor‐1α were quantified. Mean age was 63±9 years; 76% were men. The incidence of ExMI was 31% and 41% during exercise and pharmacological stress testing, respectively. Patients with ExMI had a significant decrease in CD34+/chemokine (C‐X‐C motif) receptor 4 (−18%, P=0.01) after stress that was inversely correlated with the magnitude of ischemia (r=−0.19, P=0.003). In contrast, patients without ExMI had an increase in CD34+/chemokine (C‐X‐C motif) receptor 4 (14.7%, P=0.02), and those undergoing pharmacological stress had no change. Plasma vascular endothelial growth factor levels increased (15%, P
- Published
- 2018
- Full Text
- View/download PDF
40. Place not race: community-level social determinants of health may be more important than patient race in total hip arthroplasty outcomes
- Author
-
B. Mehta, Y. Wu, D. Pearce-Fisher, K. Ho, S.M. Goodman, M. Parks, F. Wang, M. Fontana, S. Ibrahim, P. Cram, and R. Caruana
- Subjects
Rheumatology ,Biomedical Engineering ,Orthopedics and Sports Medicine - Published
- 2023
- Full Text
- View/download PDF
41. Summary of Living on the Edge: An American Generation’s Journey Through the Twentieth Century
- Author
-
Richard A. Settersten, Glen H. Elder, and Lisa D. Pearce
- Subjects
History ,Social Sciences (miscellaneous) - Abstract
Living on the Edge: An American Generation’s Journey through the Twentieth Century (University of Chicago Press, 2021) tells the story of the rarely studied 1900 generation, from their social origins to their old age, as they coped with and adapted to the revolutionary changes of the last century. Using longitudinal data from the Berkeley Guidance Study, the authors followed 420 parents (210 couples) born between 1885 and 1908, all of whom had children born in Berkeley between 1928–29. The analyses, which often challenge conventional wisdom, reveal their status as a “hinge generation,” or bridge, between past and present in their educational, work, and family experiences. Following highlights from the authors, four scholars offer critical commentary on the book. Matt Nelson addresses challenges related to analyzing kinship networks and patterns of economic assistance across the Great Depression era, pointing to measurement limitations that obscure important forms of aid. Kelly Condit-Shrestha raises concerns related to race and ethnicity, especially the absence of Black, American Indian, Chinese, Japanese, and Hispanic persons in the original study, as well as to westward migration, American Empire, and white-settler colonialism. Silvia Pedraza addresses crucial social class differences (middle class versus working class) in the expectations and experiences of women, calling for greater clarity in the relationship between women’s roles and notions of “respectability.” Finally, Evan Roberts takes up some of the complex methodological issues involved in leveraging historical data to understand the life course and identifying the uniquely disruptive nature of social change across generations and countries.
- Published
- 2022
- Full Text
- View/download PDF
42. Associations Between Inflammation, Cardiovascular Regenerative Capacity, and Cardiovascular Events: A Cohort Study
- Author
-
Anurag Mehta, Yi-An Ko, Mohammad S. Hussain, Zakaria Almuwaqqat, Kasra Moazzami, Jeong Hwan Kim, Arshed A. Quyyumi, Jamil Alkhalaf, Edmund K. Waller, Brad D. Pearce, Bruno B Lima, J. Douglas Bremner, Viola Vaccarino, Amit J. Shah, Mariana Garcia, and Samaah Sullivan
- Subjects
Male ,medicine.medical_specialty ,Time Factors ,Myocardial Infarction ,Antigens, CD34 ,Inflammation ,Coronary Artery Disease ,Risk Assessment ,Gastroenterology ,Article ,Coronary artery disease ,Risk Factors ,Internal medicine ,Humans ,Regeneration ,Medicine ,Prospective Studies ,Myocardial infarction ,Interleukin 6 ,Prospective cohort study ,Aged ,biology ,Interleukin-6 ,business.industry ,Stem Cells ,C-reactive protein ,Middle Aged ,Prognosis ,medicine.disease ,C-Reactive Protein ,Cohort ,biology.protein ,Female ,Inflammation Mediators ,medicine.symptom ,Cardiology and Cardiovascular Medicine ,business ,Biomarkers ,Follow-Up Studies ,Cohort study - Abstract
Objective: Circulating progenitor cells possess immune modulatory properties and might mitigate inflammation that is characteristic of patients with coronary artery disease. We hypothesized that patients with fewer circulating progenitor cells (CPCs) will have higher inflammatory markers and worse outcomes. Approach and Results: Patients with stable coronary artery disease were enrolled in a prospective study enumerating CPCs as CD (cluster of differentiation)-34–expressing mononuclear cells (CD34+) and inflammation as levels of IL (interleukin)-6 and high-sensitivity CRP (C-reactive protein) levels. Patients were followed for 5 years for the end points of death and myocardial infarction with repeat inflammatory biomarkers measured after a median of 2 years. In the entire cohort of 392 patients, IL-6 and high-sensitivity CRP levels remained unchanged (0.3±2.4 pg/mL and 0.1±1.0 mg/L; P =0.45) after 2 years. CPC counts (log-transformed) were inversely correlated with the change in IL-6 levels (r, −0.17; P Conclusions: Reduced cardiovascular regenerative capacity is independently associated with progressive inflammation in patients with coronary artery disease that in turn is associated with poor outcomes. Graphic Abstract: A graphic abstract is available for this article.
- Published
- 2021
- Full Text
- View/download PDF
43. Globalist Nihilism, Liberal Relativism, and Tutorialist Statecraft
- Author
-
Colin D. Pearce
- Published
- 2023
- Full Text
- View/download PDF
44. A City Where Socrates Need Not Die Paper
- Author
-
Colin D. Pearce
- Subjects
History ,Polymers and Plastics ,Business and International Management ,Industrial and Manufacturing Engineering - Published
- 2023
- Full Text
- View/download PDF
45. Potential Grape-Derived Contributions to Volatile Ester Concentrations in Wine
- Author
-
Paul K. Boss, Anthony D. Pearce, Yanjia Zhao, Emily L. Nicholson, Eric G. Dennis, and David W. Jeffery
- Subjects
grape ,wine ,ester ,amino acid ,CoA ,yeast ,fermentation ,Organic chemistry ,QD241-441 - Abstract
Grape composition affects wine flavour and aroma not only through varietal compounds, but also by influencing the production of volatile compounds by yeast. C9 and C12 compounds that potentially influence ethyl ester synthesis during fermentation were studied using a model grape juice medium. It was shown that the addition of free fatty acids, their methyl esters or acyl-carnitine and acyl-amino acid conjugates can increase ethyl ester production in fermentations. The stimulation of ethyl ester production above that of the control was apparent when lower concentrations of the C9 compounds were added to the model musts compared to the C12 compounds. Four amino acids, which are involved in CoA biosynthesis, were also added to model grape juice medium in the absence of pantothenate to test their ability to influence ethyl and acetate ester production. β-Alanine was the only one shown to increase the production of ethyl esters, free fatty acids and acetate esters. The addition of 1 mg∙L−1 β-alanine was enough to stimulate production of these compounds and addition of up to 100 mg∙L−1 β-alanine had no greater effect. The endogenous concentrations of β-alanine in fifty Cabernet Sauvignon grape samples exceeded the 1 mg∙L−1 required for the stimulatory effect on ethyl and acetate ester production observed in this study.
- Published
- 2015
- Full Text
- View/download PDF
46. Interest, Concerns, and Attitudes Among Men Who Have Sex With Men and Health Care Providers Toward Prophylactic Use of Doxycycline Against Chlamydia trachomatis Infections and Syphilis
- Author
-
Justin J Park, Chrysovalantis Stafylis, Jeffrey R. Taylor, Noah Kojima, Daniel D Pearce, Jeffrey D. Klausner, Susan J. Little, and Aleksandr M. Gorin
- Subjects
Male ,Microbiology (medical) ,Health Knowledge, Attitudes, Practice ,medicine.medical_specialty ,Health Personnel ,Chlamydia trachomatis ,HIV Infections ,Dermatology ,Drug resistance ,medicine.disease_cause ,Medical and Health Sciences ,Men who have sex with men ,Sexual and Gender Minorities ,Clinical Research ,Behavioral and Social Science ,Health care ,medicine ,Humans ,Syphilis ,Homosexuality, Male ,Doxycycline ,Practice ,business.industry ,Health Knowledge ,Prevention ,Public health ,Public Health, Environmental and Occupational Health ,Homosexuality ,Biological Sciences ,medicine.disease ,Editorial ,Cross-Sectional Studies ,Good Health and Well Being ,Infectious Diseases ,Attitude ,Attitudes ,Family medicine ,Sexually Transmitted Infections ,HIV/AIDS ,Pre-Exposure Prophylaxis ,Public Health ,Willingness to accept ,Infection ,business ,medicine.drug - Abstract
BACKGROUND Prophylactic administration of doxycycline is regarded as a potential new public health strategy to combat the rising rates of Chlamydia trachomatis infections and syphilis among men who have sex with men. We conducted a survey-based study to evaluate how community members and health care providers in Southern California would perceive doxycycline preexposure/postexposure prophylaxis (PrEP/PEP) to predict its acceptability and identify potential areas of concern. METHODS We conducted an online cross-sectional survey among community members who identify as men who have sex with men and health care providers with prescribing authority in Southern California to investigate the current attitudes toward doxycycline PrEP/PEP, including their willingness to accept. We analyzed the data using descriptive statistics and binary logistic regression. RESULTS Among 212 enrolled community member participants, 67.5% indicated they would take doxycycline PrEP/PEP if offered by their provider. Higher acceptability was significantly associated with several characteristics, including recent history of bacterial sexually transmitted infection diagnosis and current use of HIV PrEP. For health care providers, 89.5% of 76 enrolled participants expressed willingness to prescribe doxycycline PrEP/PEP to their patients if recommended by the Centers for Disease Control and Prevention, but only 43.4% were willing if not. Both community members and health care providers demonstrated high levels of concern toward possible drug resistance. CONCLUSIONS Doxycycline PrEP/PEP as a preventive strategy against chlamydial infections and syphilis would likely be accepted among community members and health care providers. Clear guidelines from public health officials and further clarification on the strategy's potential impact on developing drug resistance may be necessary to ensure successful implementation.
- Published
- 2021
- Full Text
- View/download PDF
47. Hot exozodis: cometary supply without trapping is unlikely to be the mechanism
- Author
-
Tim D Pearce, Florian Kirchschlager, Gaël Rouillé, Steve Ertel, Alexander Bensberg, Alexander V Krivov, Mark Booth, Sebastian Wolf, and Jean-Charles Augereau
- Subjects
Earth and Planetary Astrophysics (astro-ph.EP) ,zodiacal dust ,HOSTS SURVEY ,SUNGRAZING COMETS ,CONSTRAINTS ,FOS: Physical sciences ,Astronomy and Astrophysics ,Physics and Astronomy ,Astrophysics - Solar and Stellar Astrophysics ,Space and Planetary Science ,DEBRIS-DISC ,PARTICLES ,CA-II ,PICTORIS CIRCUMSTELLAR DISK ,circumstellar matter [stars] ,planetary systems ,INFRARED INTERFEROMETRIC SURVEY ,INTERSTELLAR DUST ,STARS ,Solar and Stellar Astrophysics (astro-ph.SR) ,Astrophysics - Earth and Planetary Astrophysics - Abstract
Excess near-infrared emission is detected around one fifth of main-sequence stars, but its nature is a mystery. These excesses are interpreted as thermal emission from populations of small, hot dust very close to their stars (`hot exozodis'), but such grains should rapidly sublimate or be blown out of the system. To date, no model has fully explained this phenomenon. One mechanism commonly suggested in the literature is cometary supply, where star-grazing comets deposit dust close to the star, replenishing losses from grain sublimation and blowout. However, we show that this mechanism alone is very unlikely to be responsible for hot exozodis. We model the trajectory and size evolution of dust grains released by star-grazing comets, to establish the dust and comet properties required to reproduce hot-exozodi observations. We find that cometary supply alone can only reproduce observations if dust ejecta has an extremely steep size distribution upon release, and the dust-deposition rate is extraordinarily high. These requirements strongly contradict our current understanding of cometary dust and planetary systems. Cometary supply is therefore unlikely to be solely responsible for hot exozodis, so may need to be combined with some dust-trapping mechanism (such as gas or magnetic trapping) if it is to reproduce observations., 18 pages, 9 figures, accepted for publication in MNRAS
- Published
- 2022
48. An experimental and theoretical investigation of HCN production in the Hadean Earth atmosphere
- Author
-
Ben K. D. Pearce, Chao He, and Sarah M. Hörst
- Subjects
Earth and Planetary Astrophysics (astro-ph.EP) ,Chemical Physics (physics.chem-ph) ,Atmospheric Science ,Physics - Atmospheric and Oceanic Physics ,Space and Planetary Science ,Geochemistry and Petrology ,Physics - Chemical Physics ,Atmospheric and Oceanic Physics (physics.ao-ph) ,FOS: Physical sciences ,Astrophysics - Earth and Planetary Astrophysics - Abstract
A critical early stage for the origin of life on Earth may have involved the production of hydrogen cyanide (HCN) in a reducing, predominantly H$_2$ atmosphere. HCN is crucial for the origin of life as it is a possible precursor to several biomolecules that make up RNA and proteins including nucleobases, nucleotides, amino acids, and ribose. In this work, we perform an in depth experimental and theoretical investigation of HCN production in reducing atmospheric conditions (89-95% H$_2$) possibly representing the earliest stages of the Hadean eon, ~4.5-4.3 billion years ago. We make use of cold plasma discharges - a laboratory analog to shortwave UV radiation - to simulate HCN production in the upper layers of the atmosphere for CH$_4$ abundances ranging from 0.1-6.5%. We then combine experimental mass spectrum measurements with our theoretical plasma models to estimate the HCN concentrations produced in our experiments. We find that upper atmospheric HCN production scales linearly with CH$_4$ abundance with the relation [HCN] = 0.13 $\pm$ 0.01[CH$_4$]. Concentrations of HCN near the surface of the Hadean Earth are expected to be about 2-3 orders of magnitude lower. The addition of 1% water to our experiments results in a ~50% reduction in HCN production. We find that four reactions are primarily responsible for HCN production in our experiments: (i) $^4$N + CH$_3$ -> H$_2$CN + H -> HCN + H$_2$, (ii) $^4$N + CH -> CN + H followed by CN + CH$_4$ -> HCN + CH$_3$, (iii) C$_2$H$_4$ + $^4$N -> HCN + CH$_3$, and (iv) $^4$N + $^3$CH$_2$ -> HCN + H. The most prebiotically favorable Hadean atmosphere would have been very rich in CH$_4$ (> 5%), and as a result of greenhouse effects the surface would be likely very hot. In such a prebiotic scenario, it may have been important to incorporate HCN into organic hazes that could later release biomolecules and precursors into the first ponds., Accepted for publication in ACS Earth and Space Chemistry, 24 pages, 7 figures, 5 tables, Supporting info
- Published
- 2022
49. Understanding PrEP decision making among pregnant women in Lilongwe, Malawi: A mixed‐methods study
- Author
-
Lauren M. Hill, Carol E. Golin, Friday Saidi, Twambilile Phanga, Jennifer Tseka, Alinda Young, Lisa D. Pearce, Suzanne Maman, Benjamin H. Chi, and Wilbroad Mutale
- Subjects
Malawi ,Infectious Diseases ,Anti-HIV Agents ,Pregnancy ,Decision Making ,Public Health, Environmental and Occupational Health ,Humans ,Female ,HIV Infections ,Pre-Exposure Prophylaxis ,Pregnant Women - Abstract
Pre-exposure prophylaxis (PrEP) is a promising tool for HIV prevention during pregnancy. With increasing rollout in antenatal settings, counselling strategies to help pregnant women make appropriate decisions about PrEP use are needed. Understanding women's motivations and concerns for PrEP use-and how these inform their decision making and feelings about the decision to start PrEP-are critical to inform these strategies.We conducted a convergent mixed-methods study from June 2020 to June 2021 in the context of a PrEP adherence support trial among HIV-negative pregnant women in Lilongwe, Malawi. Two hundred women completed a survey reporting their motivations and concerns about PrEP use, and their feelings about the decision to start PrEP (Decisional Regret Scale). Thirty women completed in-depth interviews to better understand the decision-making process, including motivations and concerns weighed in women's decision to use PrEP. Analyses comprised descriptive and bivariate statistics, thematic qualitative analysis, and integration of quantitative and qualitative results.Women initiating PrEP during pregnancy were highly motivated to obtain HIV protection for themselves and their unborn child, often due to perceived HIV risk connoted by a recent sexually transmitted infection and/or concerns about partner non-monogamy. These motivations prevailed despite some concerns about safety and side effects, anticipated stigmatization, and concerns about adherence burden and pill attributes. Many women had informed their partner of their decision to use PrEP yet few felt their decision was contingent upon partner approval. Most women felt positively about the decision to start PrEP (mean decisional regret = 1.2 out of 5), but those with a greater number of concerns reported greater decisional regret (B = 0.036; p = 0.005). Furthermore, women who were specifically concerned about partner disclosure, who disliked pills or who had no perceived HIV risk reported greater decisional regret.Pregnant women were strongly motivated by the promise of HIV protection offered by PrEP and accepted it despite diverse concerns. A shared decision-making approach that centres pregnant women and offers partner involvement may help identify and address initial concerns about PrEP use and support prevention-effective use of PrEP during this important period.
- Published
- 2022
- Full Text
- View/download PDF
50. Child Maltreatment and Inflammatory Response to Mental Stress Among Adults who Have Survived a Myocardial Infarction
- Author
-
Shakira F. Suglia, Shakia T. Hardy, Alison L. Cammack, Ye Ji Kim, Bradley D. Pearce, Amit J. Shah, Samaah Sullivan, Matthew Wittbrodt, J. Douglas Bremner, and Viola Vaccarino
- Subjects
Adult ,Male ,Psychiatry and Mental health ,Matrix Metalloproteinase 9 ,Interleukin-6 ,Myocardial Infarction ,Humans ,Female ,Child Abuse ,Middle Aged ,Child ,Applied Psychology ,Retrospective Studies - Abstract
Experiences of child maltreatment are associated with cardiovascular risk and disease in adulthood; however, the mechanisms underlying these associations are poorly understood.We examined associations between retrospectively self-reported exposure to child maltreatment (Early Trauma Inventory Self-Report Short Form) and inflammatory responses to mental stress among adults (mean age = 50 years) who recently had a myocardial infarction ( n = 227). Inflammation was assessed as blood interleukin-6 (IL-6), matrix metalloproteinase-9 (MMP-9), and monocyte chemoattractant protein-1 concentrations, measured before and after a standardized public speaking stress task. We used mixed linear regression models adjusting for cardiovascular disease severity, medication usage, and psychosocial, demographic, and life-style factors.In women, increases in IL-6 levels and MMP-9 levels with stress were smaller in those exposed to sexual abuse, relative to those unexposed (IL-6 geometric mean increases = 1.6 [95% confidence interval {CI} = 1.4-1.9] pg/ml versus 2.1 [95% CI = 1.8-2.4] pg/ml; MMP-9 geometric mean increases = 1.0 [95% CI = 0.9-1.2] ng/ml versus 1.2 [95% CI = 1.1-1.4] ng/ml). No differences were noted for emotional or physical abuse. By contrast in men, individuals exposed to sexual abuse had larger IL-6 responses than those not exposed to abuse.These findings suggest sex differences in stress response among survivors of a myocardial infarction exposed to abuse early in life. They also underscore the importance of examining sex as an effect modifier of relationships between exposure to early life adversity and inflammatory responses to mental stressors in midlife.
- Published
- 2022
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.