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result(s) for
"Burch, Sarah L."
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Understanding climate change and resilience: assessing strengths and opportunities for adaptation in the Global South
2017
Better integration of resilience and climate change adaptation can help building climate-resilient development. Yet, resilience and adaptation to climate change have evolved largely along parallel paths with little cross-fertilization. Conceptual vagueness around resilience makes it challenging to ascertain what elements of resilience thinking have the greatest potential to enhance climate change adaptation and contribute to broader sustainable development goals. This article distills nine principles from the resilience literature to build a framework to assess 224 climate change adaptation strategies proposed by researchers and practitioners in Africa, Asia, and Latin America. Our analysis concludes that adaptation strategies in this data set emphasize initiatives that increase social and ecological diversity, strengthen learning processes, build functional redundancy, enhance connectivity between social and ecological elements, pay attention to the management of slow variables, and provide mechanisms for increasing participation and polycentric governance. At the same time, the adaptation options examined generally lacked a system’s perspective, suggesting that there is still important work ahead to move toward a climate-resilient development model.
Journal Article
Sustainable business models in ‘lighthouse’ small to medium enterprises
by
Farrelly, Megan
,
Ramesh, Pavit
,
Fabianke, Kyra
in
Business models
,
Entrepreneurs
,
Entrepreneurship
2024
Addressing major global environmental and social challenges requires transformation of the private sector. Small- to medium-sized enterprises (SMEs) constitute 90% of private organisations globally, resulting in calls for research into the strategic roles SMEs can play in shaping sustainable futures through adopting sustainable business models (SBMs). The purpose of our study is to understand the factors that allow SMEs to successfully adopt SBMs. We used an exploratory qualitative approach drawing on interviews with SMEs implementing SBMs. Our findings extend contemporary insights by revealing the important role of the external support (‘enabling’) environment, and identifying—potentially transformative—capabilities that can help steer SMEs’ transitions to SBMs. These include persistence, tenacity, flexibility, adaptability, and a willingness to learn and fail. They enable SMEs to successfully operate in times of uncertainty and rapid changes in the external environment, and respond to new requirements through changes to their business models.
Journal Article
Climate change visioning
2013
Amidst wavering political support and faltering international climate change negotiations, sub-national governments and communities have become loci for climate change policy, planning, and action (cf. City of Vancouver 2010; GLA 2007). Local governments and civil society actors can, in some circumstances, play a leadership role and foster collective action on environmental issues (Bulkeley and Betsill 2005, 2003). Furthermore, in a pragmatic sense, most, if not all, communities around the world will need to implement plans and actions to address local adaptation as the effects of climate change become more serious.
Book Chapter
Fallout plume of submerged oil from Deepwater Horizon
by
Valentine, David L.
,
Bagby, Sarah C.
,
Reddy, Christopher M.
in
Average linear density
,
Biomarkers
,
Contamination
2014
Significance Following the sinking of the Deepwater Horizon in the Gulf of Mexico an unprecedented quantity of oil irrupted into the ocean at a depth of 1.5 km. The novelty of this event makes the oil’s subsequent fate in the deep ocean difficult to predict. This work identifies a fallout plume of hydrocarbons from the Macondo Well contaminating the ocean floor over an area of 3,200 km ². Our analysis suggests the oil initially was suspended in deep waters and then settled to the underlying sea floor. The spatial distribution of contamination implicates accelerated settling as an important fate for suspended oil, supports a patchwork mosaic model of oil deposition, and frames ongoing attempts to determine the event’s impact on deep-ocean ecology.
The sinking of the Deepwater Horizon in the Gulf of Mexico led to uncontrolled emission of oil to the ocean, with an official government estimate of ∼5.0 million barrels released. Among the pressing uncertainties surrounding this event is the fate of ∼2 million barrels of submerged oil thought to have been trapped in deep-ocean intrusion layers at depths of ∼1,000–1,300 m. Here we use chemical distributions of hydrocarbons in >3,000 sediment samples from 534 locations to describe a footprint of oil deposited on the deep-ocean floor. Using a recalcitrant biomarker of crude oil, 17α(H),21β(H)-hopane (hopane), we have identified a 3,200-km ² region around the Macondo Well contaminated by ∼1.8 ± 1.0 × 10 ⁶ g of excess hopane. Based on spatial, chemical, oceanographic, and mass balance considerations, we calculate that this contamination represents 4–31% of the oil sequestered in the deep ocean. The pattern of contamination points to deep-ocean intrusion layers as the source and is most consistent with dual modes of deposition: a “bathtub ring” formed from an oil-rich layer of water impinging laterally upon the continental slope (at a depth of ∼900–1,300 m) and a higher-flux “fallout plume” where suspended oil particles sank to underlying sediment (at a depth of ∼1,300–1,700 m). We also suggest that a significant quantity of oil was deposited on the ocean floor outside this area but so far has evaded detection because of its heterogeneous spatial distribution.
Journal Article
Persistence and biodegradation of oil at the ocean floor following Deepwater Horizon
by
Valentine, David L.
,
Fisher, G. Burch
,
Aeppli, Christoph
in
Alkanes - analysis
,
Biodegradation
,
Biodegradation, Environmental
2017
The 2010 Deepwater Horizon disaster introduced an unprecedented discharge of oil into the deep Gulf of Mexico. Considerable uncertainty has persisted regarding the oil’s fate and effects in the deep ocean. In this work we assess the compound-specific rates of biodegradation for 125 aliphatic, aromatic, and biomarker petroleum hydrocarbons that settled to the deep ocean floor following release from the damaged Macondo Well. Based on a dataset comprising measurements of up to 168 distinct hydrocarbon analytes in 2,980 sediment samples collected within 4 y of the spill, we develop a Macondo oil “fingerprint” and conservatively identify a subset of 312 surficial samples consistent with contamination by Macondo oil. Three trends emerge from analysis of the biodegradation rates of 125 individual hydrocarbons in these samples. First, molecular structure served to modulate biodegradation in a predictable fashion, with the simplest structures subject to fastest loss, indicating that biodegradation in the deep ocean progresses similarly to other environments. Second, for many alkanes and polycyclic aromatic hydrocarbons biodegradation occurred in two distinct phases, consistent with rapid loss while oil particles remained suspended followed by slow loss after deposition to the seafloor. Third, the extent of biodegradation for any given sample was influenced by the hydrocarbon content, leading to substantially greater hydrocarbon persistence among the more highly contaminated samples. In addition, under some conditions we find strong evidence for extensive degradation of numerous petroleum biomarkers, notably including the native internal standard 17α(H),21β(H)-hopane, commonly used to calculate the extent of oil weathering.
Journal Article
MMS Observations of a Compressed, Strongly Driven Magnetopause During the 2024 Mother's Day Storm
by
Fuselier, Stephen A
,
Sun, Weijie
,
Genestreti, Kevin J
in
Charged particles
,
Coronal mass ejection
,
Driving conditions
2025
From 10 to 12 May 2024, a series of coronal mass ejections led to one of the strongest geomagnetic storms of the century, referred to as the Mother's Day or Gannon Storm. MMS's position on the dayside magnetosphere on 11 May provided observations of a strongly driven and compressed ∼7RE$\\left(\\sim 7\\ {R}_{E}\\right)$reconnecting magnetopause. Because of the driving conditions, the magnetopause became saturated with O+${O}^{+}$outflows that dominated the mass density of the plasma environment. In the reconnecting magnetopause, MMS observes signatures of parallel electron heating on the magnetopause's magnetosheath side, but anomalous and significant electron cooling, especially from the perpendicular electron temperature on the magnetosphere side, possibly driven by additional mechanisms besides reconnection. Even with the strong driving and O+${O}^{+}$outflows, we find an expected (0.19±0.04)$(0.19\\pm 0.04)$normalized reconnection rate for the primary exhaust, indicating insensitivity to these conditions. The unnormalized rate, however, is atypically large and scales with the driving conditions.
Journal Article
Alpha Particle Temperature Anisotropy in Earth’s Magnetosheath
by
Matthaeus, William H
,
Fuselier, Stephen A
,
Giles, Barbara L
in
Alpha particles
,
Alpha rays
,
Anisotropy
2022
In magnetized plasmas, temperature anisotropy manifests as distinct temperatures (T ⊥j , T ∥j ). Numerous prior studies have demonstrated that as plasma beta (β ∥j ) increases, the range of temperature anisotropy (R j = T ⊥j /T ∥j ) narrows. This limiting effect is conventionally taken as evidence that kinetic microinstabilities are active in the plasma, and has been previously observed for protons in the magnetosheath. This study is the first to use data from the Magnetic Multiscale Mission to investigate these instability-driven limits on alpha particle (ionized helium) anisotropy in Earth’s magnetosheath. The distribution of data over the (β ∥j , R j ) plane was plotted and shows the characteristic narrowing in the range of R j -values as β ∥j increases. The contours of the data distribution align well with the contours of the constant growth rate for the ion cyclotron, mirror, parallel firehose, and oblique firehose instabilities, which were calculated using linear Vlasov theory.
Journal Article
Blood total mercury and methylmercury among pregnant mothers in Charleston, South Carolina, USA
2018
BackgroundMaternal blood total mercury (THg) is a biomarker for prenatal methylmercury (MeHg) exposure. Few studies have quantified both blood THg and MeHg during pregnancy, and few studies have reported longitudinal trends.ObjectivesWe analyzed blood THg and MeHg in a cohort of pregnant mothers in Charleston, South Carolina (n = 83), and investigated whether blood THg or MeHg changed between early and late gestation.MethodsTHg and MeHg were analyzed in blood samples from early (12 ± 1.7 weeks) and late (35 ± 2.2 weeks) gestation.ResultsBlood %MeHg (of THg) averaged 63% (range: 10–114%) and 61% (range: 12–117%) during early and late gestation, respectively. In unadjusted analyses, blood MeHg decreased from early to late pregnancy (paired t-test, p = 0.04), while THg did not change (paired t-test, p = 0.34). When blood MeHg was normalized by the hematocrit, this decrease was no longer statistically significant (paired t-test, p = 0.09).ConclusionsIn unadjusted analyses, blood MeHg, but not THg, decreased significantly between early and late gestation; this decrease was due in part to hemodilution. Percent MeHg (of THg) varied by up to one order of magnitude. Results highlight the importance of Hg speciation in maternal blood samples to assess prenatal MeHg exposure.
Journal Article
Safety, tolerability, pharmacokinetics, and immunogenicity of the therapeutic monoclonal antibody mAb114 targeting Ebola virus glycoprotein (VRC 608): an open-label phase 1 study
2019
mAb114 is a single monoclonal antibody that targets the receptor-binding domain of Ebola virus glycoprotein, which prevents mortality in rhesus macaques treated after lethal challenge with Zaire ebolavirus. Here we present expedited data from VRC 608, a phase 1 study to evaluate mAb114 safety, tolerability, pharmacokinetics, and immunogenicity.
In this phase 1, dose-escalation study (VRC 608), conducted at the US National Institutes of Health (NIH) Clinical Center (Bethesda, MD, USA), healthy adults aged 18–60 years were sequentially enrolled into three mAb114 dose groups of 5 mg/kg, 25 mg/kg, and 50 mg/kg. The drug was given to participants intravenously over 30 min, and participants were followed for 24 weeks. Participants were only enrolled into increased dosing groups after interim safety assessments. Our primary endpoints were safety and tolerability, with pharmacokinetic and anti-drug antibody assessments as secondary endpoints. We assessed safety and tolerability in all participants who received study drug by monitoring clinical laboratory data and self-report and direct clinician assessment of prespecified infusion-site symptoms 3 days after infusion and systemic symptoms 7 days after infusion. Unsolicited adverse events were recorded for 28 days. Pharmacokinetic and anti-drug antibody assessments were completed in participants with at least 56 days of data. This trial is registered with ClinicalTrials.gov, number NCT03478891, and is active but no longer recruiting.
Between May 16, and Sept 27, 2018, 19 eligible individuals were enrolled. One (5%) participant was not infused because intravenous access was not adequate. Of 18 (95%) remaining participants, three (17%) were assigned to the 5 mg/kg group, five (28%) to the 25 mg/kg group, and ten (55%) to the 50 mg/kg group, each of whom received a single infusion of mAb114 at their assigned dose. All infusions were well tolerated and completed over 30–37 min with no infusion reactions or rate adjustments. All participants who received the study drug completed the safety assessment of local and systemic reactogenicity. No participants reported infusion-site symptoms. Systemic symptoms were all mild and present only in four (22%) of 18 participants across all dosing groups. No unsolicited adverse events occurred related to mAb114 and one serious adverse event occurred that was unrelated to mAb114. mAb114 has linear pharmacokinetics and a half-life of 24·2 days (standard error of measurement 0·2) with no evidence of anti-drug antibody development.
mAb114 was well tolerated, showed linear pharmacokinetics, and was easily and rapidly infused, making it an attractive and deployable option for treatment in outbreak settings.
Vaccine Research Center, US National Institute of Allergy and Infectious Diseases, and NIH.
Journal Article