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Ventilation and buffering capacity effects on ocean acidification in low oxygen environments
No full textOpen Access This article is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License, which permits any non-commercial use, sharing, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if you modified the licensed material. You do not have permission under this licence to share adapted material derived from this article or parts of it. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by-nc-nd/4.0/.
This article was originally published in Nature Communications. The version of record is available at: https://doi.org/10.1038/s41467-025-67807-0Ocean acidification results from oceanic uptake of anthropogenic CO2 (ΔCant). Weak carbonate buffering capacity (high Revelle factor, RF) amplifies acidification, but its role in persistently low-oxygen, poorly ventilated regions is unclear. Here we compare preindustrial to present changes in partial pressure of CO2 (pCO2), hydrogen ion concentration ([H+]), pH, aragonite saturation state (Ωara), and RF within permanent oxygen minimum zones (OMZs) versus well-ventilated regions. We find that acidification is negligible in the least-ventilated, poorly buffered lower OMZs, but detectable in moderately ventilated upper OMZs. In upper OMZs, pCO2 and [H+] increase faster while Ωara, pH, and RF change more slowly than in adjacent well-ventilated regions. Our analysis reveals that limited ΔCant delivery by ventilation ultimately constrain acidification in low-oxygen regions. Accordingly, low-oxygen regions with poor ventilation will experience less acidification than well-ventilated regions, and different metrics (notably [H+] versus Ωara) respond distinctly due to their different definitions and sensitivities.We acknowledge the efforts of CCHDO (CLIVAR and Carbon Hydrographic Data Office) and GLODAP in supporting oceanographic research by providing access to high-quality, global, vessel-based CTD and hydrographic data from GO-SHIP, WOCE, CLIVAR and other repeat hydrography programs. L. Xue was supported by the National Key R&D Program of China (2023YFE0113101 and 2023YFC3108102), the National Natural Science Foundation of China (42176051and 42376048), the Taishan Scholar Project of Shandong Province (tsqn202306294), and the Global Ocean Negative Carbon Emissions Project (Global-ONCE). W.-J. Cai would like to thank the U.S. National Science Foundation (NSF), NASA, NOAA and the University of Delaware (internal funds) for supporting his ocean carbon cycling research
Autonomic function in women across the menopausal transition
No full textWenner, Megan M.Women experience an accelerated rise in blood pressure (BP) and cardiovascular (CV) disease risk with age compared to men, an interaction which appears to occur around the time of the menopausal transition. The autonomic nervous system tightly controls CV function, in part through the arterial baroreflex and sympathetic nervous system activity (SNA). SNA is generated in the medulla oblongata but is also influenced by higher brain regions, such as the insula, amygdala, and prefrontal cortex. SNA directly increases BP and age-related elevations in SNA contribute to elevations in BP. Interestingly, resting SNA increases more sharply with age in women than in men, mirroring the sex difference in the age-related increase in BP. The acute increases in both BP and SNA with handgrip exercise are greater in postmenopausal (POST) women compared to premenopausal women (PRE). This exaggerated pressor response is associated with increased risk of CV events and is therefore clinically relevant. However, no studies measuring autonomic CV regulation have included women just prior to menopause (perimenopausal women; PERI). Accordingly, the central hypothesis was that the menopausal transition promotes activity in central sympathetic brain regions which mediate augmented BP reactivity, SNA reactivity, and sympathetic baroreflex sensitivity as well as a reduction in cardiovagal baroreflex sensitivity. Methods: The central hypothesis was tested using 2 protocols; one in the laboratory for measurement of BP reactivity, SNA reactivity, and baroreflex sensitivity, and one in the MRI for measurement of central autonomic activity in autonomic brain regions using BOLD fMRI. In the laboratory study, we measured beat-to-beat BP and MSNA in response to sympathetic perturbations including handgrip exercise, post-exercise ischemia, the cold pressor test, and the Valsalva maneuver in PRE and PERI. In the MRI study, we used blood oxygen level dependent (BOLD) functional MRI (fMRI) to measure the BOLD signal intensity change in central autonomic brain regions in response to handgrip exercise in PRE, PERI, and POST. Results: Changes in mean arterial pressure in response to handgrip exercise (PRE 11 ± 5 vs. PERI 13 ± 8 mm Hg, P = 0.43), post-exercise ischemia (PRE 10 ± 5 vs. PERI 12 ± 8 mm Hg, P = 0.45), and the cold pressor test (PRE 18 ± 8 vs. PERI 18 ± 11 mm Hg, P = 0.95) did not significantly differ between PRE and PERI. Resting MSNA burst frequency was significantly higher in PERI compared to PRE (PRE 12 ± 5 vs. PERI 19 ± 9 bursts/min, P < 0.05). There was a significantly greater increase in MSNA burst frequency (PRE 5 ± 4 vs. PERI 14 ± 6 bursts/min, P < 0.01) in response to handgrip exercise in PERI relative to PRE, while responses to post-exercise ischemia (PRE 5 ± 3 vs. PERI 4 ± 5 bursts/min, P = 0.91) and the cold pressor test (PRE 12 ± 12 vs. PERI 14 ± 9 bursts/min, P = 0.80) did not differ between groups. Spontaneous cardiovagal baroreflex sensitivity (PRE 27 ± 10 vs. PERI 13 ± 5 ms/mm Hg, P < 0.0001) and cardiovagal baroreflex sensitivity during phase IV of the Valsalva maneuver (PRE 14 ± 7 vs. PERI 7 ± 4 ms/mm Hg, P < 0.05) were significantly lower in PERI compared to PRE, whereas cardiovagal baroreflex sensitivity during phase II of the Valsalva maneuver (PRE 8 ± 3 vs. PERI 6 ± 5 ms/mm Hg, P = 0.13) did not significantly differ between groups. Spontaneous sympathetic baroreflex sensitivity (PRE -4.0 ± 2.7 vs. PERI -3.8 ± 1.5 bursts/100 heart beats/mm Hg, P = 0.85), as well as sympathetic baroreflex sensitivity during the Valsalva maneuver (PRE -0.4 ± 0.2 vs. PERI -0.6 ± 0.3 bursts/15 sec/mm Hg, P = 0.13), did not significantly differ between PRE and PERI. During BOLD fMRI, handgrip exercise elicited significant increases in BOLD signal intensity change in the bilateral supramedullary autonomic regions of the amygdala, insula, and vmPFC, as well as in medullary autonomic regions of the NTS and RVLM, in PRE, PERI, and POST. Significant interactions between the main effects of time and menopausal group were found with the BOLD signal intensity changes in the left amygdala (Interaction: P < 0.05), left insula (Interaction: P < 0.05), and left RVLM (Interaction: P < 0.01). Post-hoc tests revealed greater left insula BOLD signal intensity changes at 90 and 100 seconds of HG in POST relative to PERI, while no significant post-hoc tests were observed with the left amygdala or left RVLM. Lastly, the average BOLD signal intensity change in the left insula during the last minute of handgrip exercise significantly differed across menopausal groups (Interaction: P < 0.05), although no significant post-hoc tests were found. Conclusion: These data demonstrate that PERI exhibit exaggerated sympathetic reactivity to HG relative to PRE, extending the timeframe for augmented sympathetic reactivity to earlier in the menopausal transition and/or aging process, with no apparent group difference in BP reactivity. PERI also exhibit attenuated cvBRS relative to PRE with no apparent difference in sBRS. These findings extend the decline in cvBRS to earlier in the menopausal transition and/or aging process than previously described, but suggest that the decline in sBRS in women may not be apparent until postmenopause. Finally, evidence for differential BOLD responses to handgrip exercise across menopausal groups was observed in the left amygdala, left insula, and left RVLM. These findings suggest that the menopausal transition and/or aging may alter both supramedullary and medullary central autonomic regulation during sympathoexcitation in women.University of Delaware, Department of Kinesiology and Applied PhysiologyPh.D
Path less traveled: gendered pathways and prison misconduct
No full textBachman, RonetExtant feminist literature argues that unique and gendered pathways lead to incarceration outcomes that vary by gender identity. Despite the large number of women involved with the prison system, both criminology and sociology of health research focus primarily on the impact of incarceration on male populations. The predominant focus of prison research on male populations influences the current body of literature examining misconduct and rule violations while incarcerated. The majority of research focuses on male-centered predictors of prison misconduct, such as mental health disorders, childhood adversity, and age. These findings advise prison programming but lack focus on gender-specific influences of prison behaviors. This hinders prison officials and policymakers from addressing the unique needs of the non-male incarcerated population. This analysis aims to investigate whether gendered pathways to incarceration have more influence on the type and severity of prison misconduct for individuals who identify as male, female, transgender, or non-binary compared to traditional, gender-neutral pathways. A secondary dataset from a nationally representative sample of people housed in state and federal prisons in 2016 was used to assess the research question. Findings indicated that female and transgender/non-binary populations have different predictors of violent and non-violent prison misconduct compared to male populations.University of Delaware, Department of Sociology and Criminal JusticePh.D
EVALUATING TUMBLE CULTURE AS A METHOD TO IMPROVE PACIFIC OYSTER (CRASSOSTREA [MAGALLANA] GIGAS) GROWTH ON SOUTHEAST ALASKA SHELLFISH FARMS
No full textenterHigh water turbulence, tidal flux, and biofouling at Alaska’s high latitude
oyster farms create various challenges for growing marketable Pacific oysters
(Crassostrea [Magallana] gigas). As oyster mariculture expands in the upper Pacific
northwest, developing efficient oyster grow-out methods is critical to ensuring
industry success. Surface culture practices, also referred to as tumble culture, are
configured to move with surface wave action and be exposed during low tide, thus
naturally tumbling oysters, deterring growth of fouling organisms, and potentially
reducing husbandry demands. To evaluate the efficiency of tumble culture in creating
marketable oysters in Alaska where this method is not currently used, we stocked 48
SEAPA baskets with 500 individual seed oysters with an average total length of 26.2
mm ± 5.44 mm (mean ± standard deviation) and monitored growth over a four-month
period. The baskets were deployed in two configurations and tidal zones (intertidal
pivot line baskets and subtidal basket stacks) at a commercial oyster farm in Juneau,
Alaska in early June 2024, and compared to the farm’s existing floating mesh bag
method. Subsets of 20 oysters were collected in late June, July, and September 2024,
to monitor shell morphology (length, width, depth), as well as whole and wet meat
weights to determine differences in growth among the gear configurations and depth
strata. The results indicate that there was a significant effect of gear configuration on
oyster growth. Subtidal basket oysters had the highest shell growth, though growth
was thin and uneven. In contrast, intertidal basket oysters had slightly lower shell
growth but had high wet meat content, producing more market desirable shell shapes
compared to the other gear configurations. Oysters from the floating mesh bag method
had high percent wet meat weight relative to their whole weight, however, these
oysters had the slowest overall growth. These results suggest that gear configuration
and depth affect oyster growth, with the intertidal basket configuration producing
oysters with desirable shell shape and wet meat weight. Ultimately these results can
inform Southeast Alaska farmers about additional methods of growing oysters that use
currently under-developed intertidal lease areas and result in well-shaped oysters.ente
Impacts of technological and educational policies on household financial behavior: evidence from China
No full textGorbachev, OlgaThis dissertation focuses on the impacts of technological and educational policies on household financial behaviors in China. My first chapter uses the 2013 Internet Finance Revolution as an exogenous policy shock to study the impact of high-speed Internet access on households' consumption and financial asset allocation in China. Using a continuous DID method, I found that being close to a fiber optic network significantly increases the proportion of risky financial assets held by households. Moreover, the fiber optic network may influence household investment via the financial inclusion channel. In terms of heterogeneity, internet access has a more significant effect on the proportion of risky financial assets held by households in urban areas, well-developed regions, old age groups, high-income groups, and better-educated households in China. ☐ Chapter two studies the direct impact of the 1986 compulsory education reform on people's educational attainment in China. I estimate the reform's effect through the combination of pre-existing location variation in program intensity and cohort exposure based on the timing of the reform. Using hand-collected data from the 1983 population census, I demonstrate that increased exposure to reform resulted in a 1.83-year improvement in children's educational achievement. By adopting the local projection method, I found that the reform has a persistent and continuously increasing impact on individuals' educational attainment. Chapter three uses the 1986 compulsory education reform as an exogenous policy shock to study the impact of education on households' financial asset allocation in China. I found that the reform increases household heads' educational attainment and their willingness to participate in financial asset markets. It also decreases the probability of owning investment properties. I find evidence of educational heterogeneity by gender as well as birthplace. However, the effect of reform has no gender and regional differences in financial asset market participation.University of Delaware, Department of EconomicsPh.D
Quantifying Diel Change in the Metabolic Rate of the Clearnose Skate (Rostroraja eglanteria)
No full textenterIn this study, we measured the routine metabolic rate (RMR) for the Clearnose
Skate (Rostroraja eglanteria) throughout the diel cycle to understand activity levels.
Intermittent flow respirometry measured oxygen consumption of skates, a proxy for
metabolic rate, during the day and night. Subtracting the day and night RMR’s, two
skates saw higher RMR’s during the day phase (Skate 1 - average difference of 63 mg
O2/hr/kg and standard deviation of 31.1 mg O2/hr/kg, Skate 3 - average difference of
21 mg O2/hr/kg and standard deviation of 37.1 mg O2/hr/kg) while one saw higher
RMR’s at night (Skate 2 - average difference of -50 mg O2/hr/kg and standard
deviation of 68.7 mg O2/hr/kg). There was no significant difference between phases.
To observe acclimation influence, the first RMR conducted was removed from each
skate. Two skates showed contradicting patterns (Skate 2 - average difference of 9.5
mg O2/hr/kg and standard deviation of 2.1 mg O2/hr/kg, Skate 3 - average difference
of -11 mg O2/hr/kg and standard deviation of 4.24 mg O2/hr/kg). No significant
statistical difference was found. The first trial RMR’s suggest that skates were stressed
when introduced to the system, thus future applications should increase acclimation
time and decrease animal handling.ente
From lab to field to farm: Applying behavioral science insights to agri-environmental programs
No full textThis article was originally published in Journal of Soil and Water Conservation. The version of record is available at: https://doi.org/10.1080/00224561.2025.2459580.
© 2025 The Author(s). Published with license by Taylor & Francis Group, LLC.
This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivatives license (http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial re-use, distribution, and reproduction in any medium, provided the original work is properly cited, and is not altered, transformed, or built upon in any way. The terms on which this article has been published allow the posting of the accepted Manuscript in a repository by the author(s) or with
their consent.Experimentation in environmental policy is often lacking because of an assumption that scientific research stops when implementation starts. However, researchers and policymakers increasingly recognize that environmental policy would benefit greatly from a more robust culture of experimentation and innovation, as has begun to develop in the areas of health and education policy (Ferraro et al. Citation2023). In the context of achieving agri-environmental policy goals, trialing new management programs is critical to generating measurable improvements that have remained elusive for decades. For example, the recent Comprehensive Evaluation of System Response (CESR) report for the Chesapeake Bay recommends more widespread use of policy implementation trials or “sandboxing” to test and evaluate the efficacy of new program rules and approaches in the face of insufficient progress on achieving Chesapeake Bay goals (Stac Citation2023).
In this article, we apply insights gained from behavioral economic experiments in the lab and field to a policy implementation trial at a multifarm scale. Approaches for forming and incentivizing the policy trial are motivated by behavioral science results, such as those that demonstrate the benefits of pay-for-performance incentive structures (Schilizzi Citation2017), incentives for spatial coordination (Banerjee et al. Citation2021; Kuhfuss et al. Citation2016), information framing in terms of social norms and peer comparisons (Allcott Citation2011; Fleming, Palm-Forster, and Kelley Citation2021; Palm-Forster et al. Citation2022), and the necessity of building trust for stakeholder-engaged resource management (Ostrom Citation2010).
In what follows, we describe resource councils as a form of stakeholder organization conducive to policy implementation trials. Then we illustrate the formation of a particular resource council in the Chesapeake Bay watershed in south-central Pennsylvania tasked with the goal of reducing streambank sediment pollution. We describe how insights from behavioral and experimental economics are applied to create incentives and supply information to allow the council to meet a shared environmental goal. Finally, we present key outcomes from the first year of the council’s work and discuss lessons learned from this approach
Structure of the Ecuadorian Upper Plate From a Joint Seismic‐Gravity Inversion
No full textThis article was originally published in Journal of Geophysical Research (JGR): Solid Earth. The version of record is available at: https://doi.org/10.1029/2024JB030667
©2025. Oak Ridge National laboratory, managed by UT‐Battelle, LLC and The Author(s). This is an open access article under the terms of the Creative Commons Attribution License CC BY 4.0, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.The Ecuadorian portion of the South American subduction zone presents an interesting case study in the structure and complex evolution of an upper plate. There are outstanding questions about its tectonic history, composition, and magmatic processes. While previous studies have employed ambient noise tomography to image the Ecuadorian upper plate, surface wave inversions alone often lack sensitivity at relevant shallow depths. This limitation can be overcome with an independent, complementary data set, such as gravity. We have jointly inverted Rayleigh wave phase velocities and Bouguer gravity anomalies to provide a more detailed seismic velocity model of the Ecuadorian upper plate. Our joint inversion has yielded several key improvements from previous models. First, we observe much shallower slow velocities beneath major basins (the Manabí, Progreso, and Gulf of Guayaquil), better aligning with expected basin structure. Second, we identify a high‐velocity block beneath the entire forearc, corresponding to the Piñon Terrane, with velocities suggesting the presence of ultramafic material. Third, we highlight a new narrow swath of slow velocities beneath the Ecuadorian Andes, which closely follows the active volcanoes along the Eastern Cordillera. The extent of these slow velocities coincides with the termination of active arc volcanism and the predicted location of the subducted Carnegie Ridge. The predicted compositions for the mid to lower crust in the region preclude a purely compositional explanation for these velocities, suggesting that some level of partial melt is necessary
