Upstream Influences Research Articles

Recurrence interval of riverbed sand mining hotspots in the Mekong delta: Potential indications of unsustainable replenishment rates

Rampant and illegal river sand mining in the Vietnamese Mekong Delta (VMD) has led to substantial sediment losses and bank erosion. However, regulation of this issue remains a significant challenge due to insufficient monitoring and enforcement efforts, partly attributed to limited data and technology. To support an improved monitoring system in the VMD, this study investigates the spatiotemporal changes in sand mining hotspots and their underlying drivers. The recurrence intervals of sand mining boats were assessed from 2014 to 2020 using Sentinel-1A, and its association with riverbed incisions were examined from bathymetry field surveys between 2017 and 2020. Our results attest to sand mining intensification from 2015 to 2020, particularly in the upstream section of the VMD, where 70% of the activity was recorded. Not only was there an apparent increase in sand mining hotspots by 32.4%, but most hotspots recorded a recurrence interval of 2 years. This potentially indicates a minimal timeframe of sediment replenishment before the same locations become economically viable for further sand extraction. Additionally, a correlation was detected between sand mining hotspots and significant riverbed incisions, although the lack of spatial overlaps in some regions suggests other upstream influences like bank collapse and river damming. Our study, through the meticulous assessment of sand mining boat movement and river bathymetry data, ultimately sheds light on the potentially unsustainable scale of sand mining activities in the VMD. It aims to support informed decision-making and effective regulations that tackle excessive sand extraction amid the dynamic environmental challenges we face, while offering valuable insights to similar deltas worldwide.

Abnormal Cerebrovascular Activity, Perfusion, and Glymphatic Clearance in Lewy Body Diseases.

Cerebrovascular activity is not only crucial to optimal cerebral perfusion, but also plays an important role in the glymphatic clearance of interstitial waste, including α-synuclein. This highlights a need to evaluate how cerebrovascular activity is altered in Lewy body diseases. This review begins by discussing how vascular risk factors and cardiovascular autonomic dysfunction may serve as upstream or direct influences on cerebrovascular activity. We then discuss how patients with Lewy body disease exhibit reduced and delayed cerebrovascular activity, hypoperfusion, and reductions in measures used to capture cerebrospinal fluid flow, suggestive of a reduced capacity for glymphatic clearance. Given the lack of an existing framework, we propose a model by which these processes may foster α-synuclein aggregation and neuroinflammation. Importantly, this review highlights several avenues for future research that may lead to treatments early in the disease course, prior to neurodegeneration. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Limbic-predominant age-related TDP-43 encephalopathy (LATE-NC): Co-pathologies and genetic risk factors provide clues about pathogenesis.

Limbic-predominant age-related TDP-43 encephalopathy neuropathologic change (LATE-NC) is detectable at autopsy in more than one-third of people beyond age 85 years and is robustly associated with dementia independent of other pathologies. Although LATE-NC has a large impact on public health, there remain uncertainties about the underlying biologic mechanisms. Here, we review the literature from human studies that may shed light on pathogenetic mechanisms. It is increasingly clear that certain combinations of pathologic changes tend to coexist in aging brains. Although "pure" LATE-NC is not rare, LATE-NC often coexists in the same brains with Alzheimer disease neuropathologic change, brain arteriolosclerosis, hippocampal sclerosis of aging, and/or age-related tau astrogliopathy (ARTAG). The patterns of pathologic comorbidities provide circumstantial evidence of mechanistic interactions ("synergies") between the pathologies, and also suggest common upstream influences. As to primary mediators of vulnerability to neuropathologic changes, genetics may play key roles. Genes associated with LATE-NC include TMEM106B, GRN, APOE, SORL1, ABCC9, and others. Although the anatomic distribution of TDP-43 pathology defines the condition, important cofactors for LATE-NC may include Tau pathology, endolysosomal pathways, and blood-brain barrier dysfunction. A review of the human phenomenology offers insights into disease-driving mechanisms, and may provide clues for diagnostic and therapeutic targets.

Impact of technology on upgrading slums and the moderating role of upstream influences: a contemporary approach to urban planning

This study aimed to determine the effect of technology on the upgradation of slums in Islamabad, along with the moderating role of upstream influences between them. With this concern, the researcher used a quantitative research design, and to accumulate the data, a closed-ended survey questionnaire was chosen. The sample size considered in this research was 293 participants belonging to the urban planning sector of Islamabad. To evaluate the data and hypothesized model, structural equation modeling (SEM) was used. It was also revealed that upward influences moderated the association between technology and slum upgradation significantly, particularly regarding governance, religion, and gender roles. However, this research is limited to Islamabad only; therefore, the implications of this study cannot be generalized. Consequently, it has been recommended that upward influences based on crime and mafia, along with governance, should be controlled to upgrade Islamabad-based slums.

A coalition-driven examination of organization capacity to address food insecurity in Greater Houston: a qualitative research study.

Economic and social hardships have worsened food insecurity, particularly among low income and racial-ethnic minority groups. Given the core goal of the 150+ member Houston Health Equity Collective (HEC) to reduce food insecurity by 5% in 2025, we explored member organizations' capacity and challenges faced in screening and responding to food insecurity through care coordination efforts. A twice-administered Qualtrics XM survey (Provo, Utah) with 76 organizations, followed by five focus groups with 22 of these organizations, explored reach and response efforts to food insecurity. Qualitative assessments lasted between 0.5 to 1.5 h, were audio-recorded, cleaned, coded, and thematically analyzed using NVivo, version 11 (Burlington, Massachusetts). The qualitative study was guided by a general inductive approach. In total, over 6 h of audiovisual recording were extracted, and over 100 pages of text exported to NVivo for data analysis. The research team read and coded transcripts independently using the codebook, and met routinely to discuss and resolve codes -resulting in numerous revisions to the codebook. Coding structure was discussed at multiple meetings and differences were addressed through consensus. Predominant qualitative themes impacting food insecurity screening were "stigma and cultural-related barriers", "clinic capacity and attitudes", "need to focus on upstream influences of food insecurity and SDOH needs", "impact of COVID-19", and "need for HEC system responses". Main recommendations to enhance screening and reach included improving staff culture, enhancing cultural sensitivity across organizational practices, and using shared technology to coordinate care. Respondents stated that the HEC can drive these recommendations through networking opportunities, use of shared resource directory, and placing focus on upstream factors. Recommendations to target food insecurity must focus on organizational staff responsiveness and sensitivity to patients' needs. Of equal importance is the need for increased attention to the upstream influencers and integration of systems-level interventions to holistically target the barriers impacting food insecurity.

The social determinants of mental health and professional counseling: A call to action

AbstractWe live in a complex and interconnected world with individual‐ and community‐level development and well‐being shaped by numerous variables. Given this multi‐deterministic nature of development, counselors are called to integrate the social determinants of mental health (SDMH) into key activities including clinical assessment, case conceptualization, treatment planning, prevention programming, education and training, and scientific inquiry. We discuss the consistency between the humanistic roots of the counseling profession with its values for developmental, preventative, and wellness‐oriented care and practices associated with the integration of the SDMH. We also provide a supportive rationale for the integration of SDMH into counseling practice through review of several key concepts: (a) upstream, midstream, and downstream influences on mental health; (b) the social gradient of mental health; (c) integrating population‐level perspectives on mental health and mental illness; (d) the functional roles of protective and risk factors; and (e) embodying a justice‐ and equity‐focused orientation.

Correlates of adolescent sole-, dual- and poly-use of cannabis, vaped nicotine, and combusted tobacco

BackgroundCompared to single substance use, adolescents’ use of multiple substances is associated with more severe dependence, cessation outcomes, and health risks. This study examined correlates of use and co-use of e-cigarettes, combusted tobacco, and cannabis among high school-aged (9th-12th grade, approximately aged 14–18) adolescents. MethodsWe analyzed the 2019 Massachusetts Youth Health Survey (MYHS) data to calculate the weighted means of any past 30-day sole-use of e-cigarettes, sole-use of combusted tobacco, sole-use of cannabis, dual-use of two of the above substances, and poly-use of all three substances. We then used weighted multinomial logistic regression to examine the associations between demographic, social and behavioral factors and sole-, dual-, and poly-use (vs. no use) of these substances. ResultsAmong N = 1614 respondents, any past 30-day dual-use of e-cigarettes and cannabis was the most prevalent (17.2%, SE: 1.3%). Sole-use of combusted tobacco was less than 1%, whereas 4.5% (SE: 0.7%) of respondents reported poly-use of e-cigarettes, cannabis, and combusted tobacco. Lower academic grades and self-reported depression (1 item on persistent feelings of sadness or hopelessness) were associated with increased odds of dual-use of e-cigarettes and cannabis and poly-use (vs. sole-use of any substance). Adolescents who self-reported having “any long-term emotional problems or learning disabilities” had greater odds of poly-use. ConclusionDifferent sets of correlates were associated with sole-, dual-, and poly-use, suggesting that certain adolescents may be more vulnerable than others to multiple substance use. Future research should examine potentially modifiable upstream influences, such as the home environment and socioeconomic factors that may affect the relationship between adolescent mental health, school performance, and multiple addictive substance use.

Social networks and social support of older immigrants in Aotearoa New Zealand

Abstract Immigrants commonly report difficulties with developing social connections post-transition, which can lead to social isolation as they age. Understanding what factors promote/hinder the social integration of immigrants is an important public health objective. We tested the public health model of social integration of Berkman et al. in a sample of older immigrants. This model calls for considering both the social conditions in which social networks are embedded (upstream influences) and the levels of social support offered by different types of networks (downstream influences). First, we derived an empirical typology of social networks of older immigrants. Next, we tested associations of social networks with upstream and downstream influences. Data came from the New Zealand Health, Work and Retirement Study. The sample included 568 older adults (54% male) who immigrated as adults (mean length of stay = 28.5 years, standard deviation = 12.5). Latent profile analysis was employed on responses to the Practitioner Assessment of Network Type to identify social networks. Associations with upstream and downstream correlates were tested using logistic and multiple regression. Four network configurations emerged: ‘private-restricted’ (43.4%), ‘family-dependent’ (35.8%), ‘locally integrated’ (10.9%) and ‘wider community-based’ (9%). Having shorter length of residence and individualistic cultural background was predictive of being in a restricted network (private-restricted, family-dependent). Being in a restricted network was associated with lower levels of social support. Network type interacted with partner status: having a partner buffered the negative impact of having a restricted network on social support. Although restricted networks are common among older immigrants, they do not necessarily result in compromised social support. While we may see differences across countries regarding the impact of specific upstream and downstream influences, our findings highlight that both contextual and individual-level resources need to be considered alongside network structure to promote social integration of immigrants as they age.

Tax Compliance in the Wild: Critical Review of Nudging and Proposition of an Integrative Framework

Context: There is an inflation of behavioral frameworks applied to social problems, such as tax dodging. There has been also a surge in the creation of the so-called nudge units throughout the world, following the success of the pioneer units in USA and UK. Meanwhile, there has been criticism directed at aspects such as ‘psychologism,’ paternalism, and short-termism associated with nudge approaches. Moreover, by ignoring systems thinking, complexity science and other broader approaches, nudging may lead to interventions that can be ineffective or counterproductive in the long term. Goal: To overcome such limitations, the paper proposes an integrative framework, the Nested Circles Model, which put the intended behaviors in a perspective ranging from microworlds to broader upstream influences. Method: The paper employs a qualitative approach to critically review the literature on nudging and map its shortcomings. Results and contributions: The proposed model integrates major concepts from popular behavioral frameworks and incorporates elements that influence the repertoire of behaviors adopted by individuals, including intangible stocks (trust and fairness) and complexity markers. The paper concludes by exemplifying the application of the Nested Circles Model to three problems in the context of taxation in Brazil.

Diverse controlling mechanisms and teleconnections of three distinctive MJO types

In this diagnostic study, three distinctive MJO types in boreal winter are documented and their controlling mechanisms and teleconnections are investigated with a synergetic glocal approach. It is revealed that the diverse nature of the MJO primarily results from different tropical-extratropical interactions and associated internal atmospheric processes. Both the type-I and type-II are initiated over the western Indian Ocean (IO) by a dry zone around the eastern IO (EIO), while only the type-I can move out the IO and circulate around the globe. The type-III initiates over the western Pacific (WP) and can circulate the globe. The strong upper-level equatorial westerly wind over the IO-WP, resulting from upstream and extratropical influences, suffocates the type-II MJO within the IO. Whereas, the robust upper-level equatorial easterly wind over the IO-WP, also resulting from upstream and extratropical influences, along with regional convective instability over the WP and the arrival of cold surge over the South China Sea (SCS) foster the development and eastward propagation of the type-III MJO. The downstream and extratropical teleconnections are primarily controlled by the associated convection over the tropical IO-WP sector for the type-I, but also strongly influenced by the conditions over the extratropical WP for the type-II and type-III. Given that the MJO has been traditionally viewed as a tropical mode owing its existence to the coupling between organized convection and large-scale circulations, present findings advocate the MJO as a glocal mode and call for more research on the involved tropical-extratropical interactions in order to better understand and simulate the diverse nature of the MJO.

Integrin Signaling Pathway Is Crucial for the Recently Divided Fraction of CLL Cells and Facilitates Cell Migration in a Disease Progressive Manner

Chronic lymphocytic leukemia (CLL) cells can be subdivided into fractions based on the time since cell birth/division. The fraction of CLL B cells bearing a CXCR4DimCD5Bright phenotype divided recently (proliferative fraction, PF), while those cells that divided earlier and are quiescent bear a CXCR4BrightCD5Dim phenotype (resting fraction, RF). Prior studies suggest that cells of the PF are recent emigrants of solid tissue, whereas cells of the RF did so earlier and are most adept at homing to lymphoid niches. Here we report gene expression and functional analyses of the PF and RF that address the signaling pathway most relevant for the PF and the relative abilities of the PF and RF to migrate using the pathway. When analyzing genes significantly differentially expressed (DEGs) between PF and RF of 26 CLL patients (13 U-CLL and 13 M-CLL), we found 198 genes upregulated in the PF and 88 in the RF. Using Ingenuity Pathway Analysis (IPA), the DEGs of the PF overlapped best with the integrin signaling pathway (Z-score = 2.887). Moreover, of the other identified pathways with Z scores > 2.0, each impacted integrin expression and function (upregulated: Actin Nucleating by ARP-WASP Complex and Regulation of Actin-based Motility by Rho; downregulated: RhoGDI signaling). To validate the transcriptomic data, mRNA and protein levels of various upregulated integrin subunits were confirmed by Q-PCR and cell surface staining by flow cytometry. When comparing the DEGs between the PF and the RF in U-CLL vs M-CLL patients, a core of 144 genes were shared by the two and 358 were unique to U-CLL and 35 to M-CLL. Notably, IPA indicated that the shared genes overlapped with the integrin signaling pathway and the U-CLL unique genes resembled pathways used by integrins to carry out their functions, such as migration. When the 3 sets of DEGs were subjected to Upstream Regulator analysis using IPA, multiple cytokines were identified as potential regulators of the DEGs shared by U-CLL and M-CLL (Z scores > 2.0) clones, whereas for the DEGs unique to the PF of U-CLL, only IL-4 was identified (Z scores = 2.6). To corroborate the above, we cultured CLL B cells for 3 days with the of putative upstream regulators of the shared and U-CLL unique DEGs. For the former, we found that [1] IFNα upregulated CD11c in all CLL, [2] IL-1 and IL-2 upregulated CD11a in all CLL, and [3] IL-1, IL-2, IFNα and IFNγ upregulated CD29 in M-CLL only. When testing a regulatory role for IL-4 in the U-CLL unique genes, we found that IL-4 upregulated CD11a, CD11c, and CD18 in U-CLL (P < 0.05), but not in M-CLL. Finally, we evaluated several functions mediated by integrin molecules. First, we tested the binding of the PF and RF to fibronectin, an important step in cell migration. This indicated that the PF bound better to fibronectin than RF (P < 0.01), and led to extended survival (P < 0.05). Consistent with this, co-culture with anti-CD49d antibody significantly blocked CLL cell adhesion to fibronectin (P < 0.01). Next, we addressed CLL cell migration. In vitro migration studies indicated that PF cells migrated significantly better than the RF with (P < 0.0001) or without (P < 0.001) CXCL12/SDF-1. In line with this, 24-hours after transferring PF and RF into NSG mice, significantly more PF than RF cells were found in the spleen (P < 0.05). Notably, the ability to more rapidly enter solid tissue associated with the rate of disease progression of individual patients (P < 0.001). Since these were unexpected findings, we questioned if sorting PF and RF altered their ability to migrate in vitro. Based on the analysis of 16 patients (U-CLL = 8, M-CLL = 8), simultaneous preincubation of CLL B cells with mAbs to CD5 plus CXCR4 did not change spontaneous nor CXCL12/SDF-1-mediated migration. Collectively, our findings indicate that integrins and the integrin signaling pathway are key elements in the biology of the recently divided fraction of CLL cells. Moreover, those DEGS that are shared by U-CLL and M-CLL cells and those unique to U-CLL are regulated by distinct upstream influences, with IL-4 standing out as a crucial cytokine for the development of the U-CLL PF. Finally, in vitro and in vivo studies suggest a key role for the integrin pathway in CLL migration, and pinpoint, surprisingly, the PF, not the RF, as the better migrater and document that the rate of migration correlates with disease activity.

Abstract 2975: RAS precision medicine transatlantic partnership: Exploration of RAS and NF1 co-mutations in NSCLC

Abstract Background: RAS is the most commonly mutated oncogene in cancer, with KRAS mutated in ~30% of non-small cell lung cancer (NSCLC). RAS is a small GTPase cycling between GTP-bound ‘ON’ state and GDP-bound ‘OFF’ state. KRAS oncoproteins cycle between these states via hydrolysis and nucleotide exchange with the aid of GAPs, including NF1, and GEFs. Given the ’inactive state’ inhibition of recently developed KRAS G12C inhibitors on the GDP-bound state, this has highlighted the continued reliance of KRAS-mutants upon cycling, and the potential for mutants to retain dependence upon upstream influences, including NF1, for pathogenicity. Methods: 474 patients with advanced RAS- and/or NF1-mutant NSCLC were retrospectively identified from four tertiary cancer centers between 2008 -2021. DNA from archival FFPE samples, serum or combination underwent targeted NGS panels to identify mutations. Molecular, clinical, pathological and treatment outcome data were collected. Online resources including cBioPortal and Project Achilles were used to assess the functional role of any findings. Results: KRAS mutations were identified in 416/474 patients and NF1-mutations in 63/474 patients, eight of whom harbored two NF1-mutations. 24/63 (38%) of NF1-mutant cancers had a concomitant KRAS-mutation. We identified that KRAS G13D was more prevalent in NF1 mutant cancers vs. NF1 wildtype (NF1 MT: 6/24, 25%; vs. NF1 WT: 4/281, 1.4%; p&amp;lt;0.0001). KRAS G12C was identified in 11/24 (45.8%) of the double mutants vs. 109/282 (38.7%) of the NF1 WT patients (p=0.52). Those with G13D/NF1 co-mutation had a predicted pathogenic NF1-mutation in 5/6 (83%) of cases. Functional analysis of NF1 KO in G13D mutant lung cancer cell lines identified that NF1 was more essential in G13D mutant cell lines, with median Chronos score -0.26 G13D vs. -0.04 G12C (p=0.02). mRNA expression data identified a range of mRNA expression Z-scores relative to all samples for NF1-mutant cancers, ranging from lowest expression at -4.54 to +1.63, median -0.51. A higher mRNA expression was identified for NF1 missense mutations of unknown significance compared to truncating mutations with likely pathogenic, loss of function. Conclusions: These results highlight the co-mutational landscape of KRAS G13D with NF1 in NSCLC, suggesting functional importance conferred by NF1 loss, and highlight NF1 mutations as an additional pathogenic even when combined with KRAS mutation. The genomic landscape of KRAS and NF1 mutant NSCLC will be explored further through Whole Genome Sequencing data from the 100,000 Genomes Project (Genomics England). Citation Format: Helen M. Adderley, Mihaela Aldea, Jaqueline Aredo, Mathew Carter, Matthew Church, Pantelis Nicola, Jamie Weaver, Aisha Ghaus, Damien Vasseur, Matthew Krebs, Nicola Steele, Fiona Blackhall, Heather Wakelee, Benjamin Besse, Colin Lindsay. RAS precision medicine transatlantic partnership: Exploration of RAS and NF1 co-mutations in NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2975.

Plants Dictate Root Microbial Composition in Hydroponics and Aquaponics.

The role of the microbial community in mediating fish and plant co-culture is often considered the black box of aquaponics. Despite widespread recognition regarding the dependency of plants on their rhizosphere, the extent to which upstream aquaculture influences downstream hydroponic root communities has been poorly described in the literature. In this study we performed a taxonomic survey (16S rRNA metabarcoding) of microbial communities originating in the facility water source, hydroponic nutrient solution (HNS) sump, nutrient supplemented biofilter effluent (BF) sump, and recirculating aquaculture system tanks stocked with Nile tilapia (Oreochromis niloticus). Lettuce (Lactuca sativa) was then grown using the HNS and BF effluent under sterilized or mature (prior aquaponics/hydroponics lettuce culture water) conditions, likewise, the influence of probiotic addition or inoculation with soil-grown lettuce rhizosphere was assessed. Compositional similarities across treatments suggest that under soil-less conditions, plants are able to exert a stronger discriminatory influence on their rhizosphere composition than is done by colonization from upstream sources. Furthermore, cluster dendrograms grouped the sterilized and unsterilized treatments more consistently together than hydroponics and aquaponics treatments. These findings contradict conventional beliefs that microbial communities in the water column colonize roots based on their presence alone, ignoring the role that plants play in rhizosphere community selection.

Nasal DNA Methylation Architecture of the {ACE2} gene and Epigenetic Aging

BACKGROUND AND AIM: Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has led to the global coronavirus disease 2019 (COVID-19) pandemic. SARS-CoV-2 enters cells via angiotensin-Converting Enzyme 2 (ACE2) receptors, highly expressed in nasal epithelium with parallel high infectivity. The nasal methylome is in direct contact with the environment and might serve as biomarker of COVID-19 disparities by reflecting social and environmental influences on {ACE2} regulation. METHODS: We collected nasal swabs from anterior nares of 547 children, measured DNA methylation (DNAm) using the Illumina EPIC array, and tested differences at 15 {ACE2} CpGs by sex, age, race/ethnicity and epigenetic age. We hypothesized that sex, age and race would influence DNA methylation of nasal cells serving as proxy for ACE2 receptors which in turn might be partially influenced by the social and chemical environment. RESULTS:{ACE2} CpGs were differentially methylated by sex with 12 sites having lower DNAm (mean=12.71%) and 3 sites greater DNAm (mean=1.45%) among females relative to males. We observed differential DNAm at 5 CpGs for Hispanic females (mean absolute difference=3.22%) and lower DNAm at 8 CpGs for Black males (mean absolute difference=1.33%), relative to white participants. Longer DNAm telomere length was associated with greater ACE2 DNAm at 11 and 13 CpGs among males (mean absolute difference=7.86%) and females (mean absolute difference=8.21%), respectively. CONCLUSIONS:Nasal {ACE2} DNAm differences could contribute to our understanding COVID-19 severity and disparities reflecting upstream environmental and social influences. Findings need to be confirmed among adults and patients with risk factors for COVID-19 severity. KEYWORDS: Epigenetics, Disparities, COVID-19

Population structure of a newly recorded (Halodule uninervis) and native seagrass (Halophila ovalis) species from an intertidal creek ecosystem

AbstractThe presence of the seagrass Halodule uninervis was documented for the first time outside the Chilika lagoon at Haripur creek, along with previously documented Halophila ovalis from the same region. The population structure (density; biomass; leaf growth rate; and morphometrics) and environmental parameters was assessed for both seagrass species. The pH levels of the water column above both seagrass meadows were lower than the standard oceanic pH of 8.2, likely attributable to upstream freshwater influences. Halophila ovalis grew on sandy and H. uninervis on silty substrates. High nutrient (nitrate and phosphate) concentrations in the water column of the creek influenced the growth of macroalgae (Ceramium sp. and Gracilaria verrucosa) on the leaves of H. uninervis. Leaf reddening was only observed in H. ovalis leaves. Under similar environmental conditions, the shoot density and biomass (above‐ and below‐ground) of H. ovalis were 2‐fold lower that for H. uninervis. The leaves of H. uninervis were 9‐fold longer than H. ovalis, whereas H. ovalis had 5‐fold wider leaves than H. uninervis. The leaf plastochrone interval of H. ovalis (2.3 days) and H. uninervis (9.6 days) was similar for the Indian Ocean region. Consequently, the H. ovalis leaf growth rate was 2‐fold lower than that for H. uninervis. H. ovalis shoot internodes were 2.6‐fold longer than for H. uninervis, whereas the root lengths of H. uninervis were longer than for H. ovalis. The shorter root length of H. ovalis resulted in a higher branching frequency than for H. uninervis. The total C and N content were higher in the H. ovalis leaves than those of H. uninervis. This study suggest seagrass responses to similar environmental conditions are species‐specific. Regular assessment of the seagrass population structure and water quality monitoring of Haripur creek are essential for better management and conservation of these important seascapes.

DNA methylation architecture of the ACE2 gene in nasal cells of children

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has led to the global coronavirus disease 2019 (COVID-19) pandemic. SARS-CoV-2 enters cells via angiotensin-Converting Enzyme 2 (ACE2) receptors, highly expressed in nasal epithelium with parallel high infectivity.1,2 The nasal epigenome is in direct contact with the environment and could explain COVID-19 disparities by reflecting social and environmental influences on ACE2 regulation. We collected nasal swabs from anterior nares of 547 children, measured DNA methylation (DNAm), and tested differences at 15 ACE2 CpGs by sex, age, race/ethnicity and epigenetic age. ACE2 CpGs were differentially methylated by sex with 12 sites having lower DNAm (mean = 12.71%) and 3 sites greater DNAm (mean = 1.45%) among females relative to males. We observed differential DNAm at 5 CpGs for Hispanic females (mean absolute difference = 3.22%) and lower DNAm at 8 CpGs for Black males (mean absolute difference = 1.33%), relative to white participants. Longer DNAm telomere length was associated with greater ACE2 DNAm at 11 and 13 CpGs among males (mean absolute difference = 7.86%) and females (mean absolute difference = 8.21%), respectively. Nasal ACE2 DNAm differences could contribute to our understanding COVID-19 severity and disparities reflecting upstream environmental and social influences. Findings need to be confirmed among adults and patients with risk factors for COVID-19 severity.

An Impulse-Regime Switching Game Model of Vertical Competition

We study a new kind of nonzero-sum stochastic differential game with mixed impulse/switching controls, motivated by strategic competition in commodity markets. A representative upstream firm produces a commodity that is used by a representative downstream firm to produce a final consumption good. Both firms can influence the price of the commodity. By shutting down or increasing generation capacities, the upstream firm influences the price with impulses. By switching (or not) to a substitute, the downstream firm influences the drift of the commodity price process. We study the resulting impulse-regime switching game between the two firms, focusing on explicit threshold-type equilibria. Remarkably, this class of games naturally gives rise to multiple potential Nash equilibria, which we obtain thanks to a verification-based approach. We exhibit three candidate types of equilibria depending on the ultimate number of switches by the downstream firm (zero, one or an infinite number of switches). We illustrate the diversification effect provided by vertical integration in the specific case of the crude oil market. Our analysis shows that the diversification gains strongly depend on the pass-through from the crude price to the gasoline price.

Abstract IA31: Structural Inequities, Social Determinants, and Survivorship: Opportunities and Strategies to Advance Health Equity

Abstract Despite considerable progress against cancer in recent decades, disparities in cancer survivorship persist. Increasingly, upstream influences are recognized as key determinants of cancer-related disparities. However, predominant strategies often neglect to consider and/or address these influences, slowing progress toward achieving cancer health equity. This presentation will discuss an integrated framework that can be used to understand and address structural and social influences on disparities in cancer survivorship. Additionally, data from diverse sources will be used to illustrate the influence of social and structural factors on cancer-related outcomes. The presentation will underscore the importance of addressing structural inequities and social determinants to help cultivate equitable outcomes among cancer survivors. Citation Format: Kassandra I. Alcaraz. Structural Inequities, Social Determinants, and Survivorship: Opportunities and Strategies to Advance Health Equity [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr IA31.

Sulfate sulfur isotopes and major ion chemistry reveal that pyrite oxidation counteracts CO2 drawdown from silicate weathering in the Langtang-Trisuli-Narayani River system, Nepal Himalaya

Drawdown of atmospheric carbon dioxide (CO2) due to silicate weathering in the Himalaya has previously been implicated in Cenozoic cooling. However, over timescales shorter than that of the removal of marine sulfate (SO42−), the oxidation of pyrite (FeS2) in weathering systems can counteract the alkalinity flux of silicate weathering and modulate pCO2. Here we present evidence from 34S/32S isotope ratios in dissolved SO42− (δ34SSO4), together with dissolved major ion concentrations, that reveals FeS2 oxidation throughout the Langtang-Trisuli-Narayani River system of the Nepal Himalaya. River water samples were collected monthly to bimonthly throughout 2011 from 16 sites ranging from the Lirung Glacier catchment through the Narayani River floodplain. This sampling transect begins in the High Himalayan Crystalline (HHC) formation and passes through the Lesser Himalayan (LH) formation with upstream influences from the Tethyn Sedimentary Series (TSS). Average δ34SSO4 in the Lirung Glacier outlet is 3.6‰, increases downstream to 6.3‰ near the confluence with the Bhote Kosi, and finally declines to −2.6‰ in the lower elevation sites. Using new measurements of major ion concentrations, inversion shows 62–101% of river SO42− is derived from the oxidation of sulfide minerals and/or organic sulfur, with the former process likely dominant. The fraction of H2SO4-driven weathering is seasonally variable and lower during the monsoon season, attributable to seasonal changes in the relative influence of shallow and deep flow paths with distinct residence times. Inversion results indicate that the primary control on δ34SSO4 is lithologically variable isotope composition, with the expressed δ34S value for the LH and TSS formations (median values −7.0–0.0‰ in 80% of samples) lower than that in the HHC (median values 1.7–6.2‰ in 80% of samples). Overall, our analysis indicates that FeS2 oxidation counteracts much of the alkalinity flux from silicate weathering throughout the Narayani River system such that weathering along the sampled transect exerts minimal impact on pCO2 over timescales >5–10 kyr and <10 Myr. Moreover, reanalysis of prior datasets suggests that our findings are applicable more widely across several of the frontal Himalayan drainages.

29.B. Workshop: Moving upstream to advance understanding of &amp; ways to address the commercial determinants of health

Abstract Poor health is increasingly determined not only by the products but by the behaviours of major corporations, notably but not exclusively, unhealthy commodity industries. Models of the determinants of health have been successfully used to advance understanding of the broad range of factors that affect health, and guide policy-makers to entry points for public health interventions. However, the existing and widely used models of social determinants insufficiently address the pervasive influence of commercial actors, such as transnational corporations, within their conceptual frameworks. While conceptual models of the commercial determinants of health and taxonomies of unhealthy commodity industry political activity have been proposed and now applied to diverse industries, there remains a need for such work to fully reflect the extent of private sector political activity. In particular, such models must recognise the corporate sector's upstream influence in shaping, for example, the overarching political environment, trade and governance structures which have both facilitated the spread of NCDs and hindered policy progress in addressing them. Going further still there is a need to recognise that these corporate practices are both enabled by and drive the modern capitalist system which in turn poses threats to human and planetary wellbeing. It is increasingly important, and indeed urgent, for public health professionals to recognise and address these issues. This workshop therefore aims to: identify limitations in existing models of the determinants of health;present new models and taxonomies which can be used to better understand and address the commercial determinants of health;present evidence on the behaviour and practices of unhealthy commodity industries that inform these latest models and taxonomies, pulling together the “silos” of evidence across, for example, tobacco, food and alcohol;examine the corporate sector's, often neglected, upstream influences over policy infrastructure, trade and governance;thereby advance understanding of how unhealthy commodity industries drive ill health and the range and nature of interventions required to address such behaviours and practices;explore how we go further still in understanding and addressing the health challenges posed by the modern capitalist system. The workshop brings together leading scholars in the field and will involve 4 overview presentations followed by detailed discussion where audience participation will be actively invited. Key messages Health is increasingly determined by the products, behaviours and practices of major corporations. We urgently need to understand and address these if we are to improve health and reduce inequalities. This workshop will propose new models for understanding how corporations influence health, focusing particularly on upstream influences on politics, trade &amp; governance &amp; how these can be addressed.