30233 research outputs found
Sort by
Biogeochemical properties of blue carbon sediments influence the distribution and monomer composition of bacterial polyhydroxyalkanoates (PHA)
Get PDFCoastal wetlands are highly efficient ‘blue carbon’ sinks which contribute to mitigating climate change through the long-term removal of atmospheric CO2 and capture of carbon (C). Microorganisms are integral to C sequestration in blue carbon sediments and face a myriad of natural and anthropogenic pressures yet their adaptive responses are poorly understood. One such response in bacteria is the alteration of biomass lipids, specifically through the accumulation of polyhydroxyalkanoates (PHAs) and alteration of membrane phospholipid fatty acids (PLFA). PHAs are highly reduced bacterial storage polymers that increase bacterial fitness in changing environments. In this study, we investigated the distribution of microbial PHA, PLFA profiles, community structure and response to changes in sediment geochemistry along an elevation gradient from intertidal to vegetated supratidal sediments. We found highest PHA accumulation, monomer diversity and expression of lipid stress indices in elevated and vegetated sediments where C, nitrogen (N), PAH and heavy metals increased, and pH was significantly lower. This was accompanied by a reduction in bacterial diversity and a shift to higher abundances of microbial community members favouring complex C degradation. Results presented here describe a connection between bacterial PHA accumulation, membrane lipid adaptation, microbial community composition and polluted C rich sediments
Engagement in water governance action situations in the Lake Champlain Basin
Get PDFWater quality governance encompasses multiple “wicked” interacting problems that manifest within social-ecological systems. Concerned governments, institutions, and actors concerned with addressing these issues must wrestle with complex systems that span time, space, and scale. This complexity of connected systems requires the participation of multiple actors across political boundaries, problem areas, and hydrologic domains. In Lake Champlain (US), frequent cyanobacteria blooms negatively affect property values, recreational activities, and public infrastructure, in addition to their impacts on the aquatic ecosystem. Through a survey of actors working on water quality in the Lake Champlain Basin, we analyze how actor participation in structured issue forums creates a network of connected action situations across multiple spatial scales and problem domains. We apply exponential random graph models to quantify the effects of scale, issues, and homophily on actor participation in these forums. Our findings show that actors tend to favor participating in similarly scoped forums at their spatial scale, that actors are less likely to participate in structured forums focused on agriculture, and that actors participate independently of others with whom they have pre-existing collaborative relationships. Further, we find that in the case of the Lake Champlain Basin, actor participation in issues related to water quality is misaligned with modeled sources of nutrient pollution. This study demonstrates that the design and maintenance of water quality action situations play an important role in attracting the participation of actors working collaboratively to address wicked social-ecological problems. Further, linking current and potential configurations of governance networks to social-ecological outcomes can aid in the effective and efficient achievement of management objectives
Ethnodemographic characterization of stroke incidence and burden of disease in hospital discharge records in Ecuador
Get PDFIntroduction: Stroke is the second most common cause of death and disability-adjusted life years (DALYs) globally. However, the incidence and impact of stroke by ethnicity and gender is frequently distinct. This is particularly the case in Ecuador where geographic and economic marginalization are often correlated with ethnic marginalization and the extent to which females lack the same opportunities as their male counterparts. The aim of this paper is to investigate the differential impacts in terms of stroke diagnosis and burden of disease by ethnicity and gender, using hospital discharge records over the years 2015–2020.
Methods: This paper calculates stroke incidence, and fatality rates using hospital discharge and death records over the years 2015–2020. The DALY package in R was employed to calculate the Disability Adjusted Life Years lost due to stroke in Ecuador.
Results: The results show that while the incidence rate of stroke in males (64.96 per 100,000 persons-year) is higher than that for females on average (57.84 per 100,000 persons-year), males accounted for 52.41% of all stroke cases and 53% of all surviving cases. Thus, hospital data suggests that females had a higher death rate when compared to males. Case fatality rates also differed significantly by ethnicity. The highest fatality rate corresponded to the Montubio ethnic group (87.65%), followed by Afrodescendants (67.21%). The estimated burden of disease of stroke calculated using Ecuadorian hospital records (2015–2020) varied from 1,468 to 2,991 DALY per 1,000 population on average.
Discussion: Differences in the burden of disease by ethnic group are likely to reflect differential access to care by region and socio-economic group, both of which are frequently correlated with ethnic composition in Ecuador. Equitable access to health services remains an important challenge in the country. The gender discrepancy in fatality rates suggests that there is a need for targeted educational campaigns to identify stroke signs early, especially in the female population
A ferritin-based COVID-19 nanoparticle vaccine that elicits robust, durable, broad-spectrum neutralizing antisera in non-human primates
Get PDFWhile the rapid development of COVID-19 vaccines has been a scientific triumph, the need remains for a globally available vaccine that provides longer-lasting immunity against present and future SARS-CoV-2 variants of concern (VOCs). Here, we describe DCFHP, a ferritin-based, protein-nanoparticle vaccine candidate that, when formulated with aluminum hydroxide as the sole adjuvant (DCFHP-alum), elicits potent and durable neutralizing antisera in non-human primates against known VOCs, including Omicron BQ.1, as well as against SARS-CoV-1. Following a booster ~one year after the initial immunization, DCFHP-alum elicits a robust anamnestic response. To enable global accessibility, we generated a cell line that can enable production of thousands of vaccine doses per liter of cell culture and show that DCFHP-alum maintains potency for at least 14 days at temperatures exceeding standard room temperature. DCFHP-alum has potential as a once-yearly (or less frequent) booster vaccine, and as a primary vaccine for pediatric use including in infants
Is hyper-selectivity a root of Asian American children's success?
Get PDFAsian immigrants' children, even those from lower-backgrounds, tend to acquire higher levels of education than other ethnoracial groups, including White natives. Asian culture is often cited as a conventional explanation. The hyper-selectivity hypothesis challenges conventional wisdom by arguing that Asian American culture is an outcome of the community resources associated with hyper-selectivity. In this study, we assess the validity of the hyper-selectivity theory by examining the association between the magnitude of hyper-selectivity measured by the proportion of the BA + degree holders among the 1st generation Asian immigrants across communities and the likelihood of school enrollment for 1.5 and 2nd + generation Asian American children. Our results cast doubt on the hyper-selectivity theory. Asian American children's school enrollment is associated with the magnitude of educational selectivity among Asian immigrants for neither high school nor college. The benefits of hyper-selectivity do not seem to be cross-class or cross Asian ethnic groups. The higher the hyper-selectivity in a community is, the larger the education gap between upper- and lower-background Asian American children. The implications of these findings are discussed
Land loss in the Mississippi River Delta: Role of subsidence, global sea-level rise, and coupled atmospheric and oceanographic processes
Get PDFThe Mississippi River Delta in coastal Louisiana has suffered large-scale land loss during the historic period and is representative of a global phenomenon where low-elevation deltaic coasts are increasingly at risk because of disrupted sediment supply and accelerated global sea-level rise. Land loss is a natural part of deltaic evolution over time, and most of the land loss in the Mississippi River Delta occurred after individual delta-plain headlands were abandoned as active constructional landscapes, but before 1932 when collection of air photos would make repeat land loss measurements possible. A coastwide land loss of ∼5000 km2 is now well documented for the period 1932 to 2016, which corresponds to a mean rate of ∼57 km2 yr−1.
We use a LiDAR digital topobathymetric model to hindcast land-area changes through time for 1950–2010 by incrementally restoring elevation lost due to subsidence, global sea-level rise, and annual anomalies in mean sea level. Our results support the view that the magnitude and spatial distribution of 20th century land loss can be explained by an unfortunate convergence of ongoing subsidence, greatly reduced sediment dispersal due to levee construction, and acceleration of global sea-level rise. Other factors have contributed to land loss on local scales, but the magnitude of land loss that has occurred would have occurred anyway due to subsidence, lack of sediment input, and accelerated sea-level rise.
Multidecadal accelerations and decelerations in land loss from 1950 to 2010 have been observed, and attributed to accelerations and decelerations in subsidence due to subsurface fluid withdrawals. However, non-linear land loss represents measurements that were made when water levels varied due to annual to multidecadal anomalies in mean sea level. Anomalies in mean sea level are driven by flux of water into and out of the Gulf of Mexico from the Atlantic, as well as the Atlantic Multidecadal Oscillation (AMO), which produces precipitation anomalies in the Gulf of Mexico drainage area, anomalies in Mississippi River discharge to the Gulf of Mexico, and changes in wind directions that serve to trap water along the coast and elevate coastal sea level, or advect water away from the coast to lower coastal sea level. Sea-level anomalies of the scale described here amplify or suppress the secular trend of global sea-level rise and its impacts on low-elevation delta plains as they respond to ongoing subsidence and anthropogenic disruption of sediment dispersal
Morphological and organic spectroscopic studies of a 44-million-year-old leaf beetle (Coleoptera: Chrysomelidae) in amber with endogenous remains of chitin
Get PDFThis study details the quality of preservation of amber deposits in the Eocene. Through Baltic amber crack-out studies using Synchrotron Micro-Computed Tomography and Scanning Electron Microscopy it was found that the cuticle of a specimen of leaf beetle (Crepidodera tertiotertiaria (Alticini: Galerucinae: Chrysomelidae)) is exceptionally well preserved. Spectroscopic analysis using Synchrotron Fourier Transform Infrared Spectroscopy suggests presence of degraded α
-chitin in multiple areas of the cuticle, and Energy Dispersive Spectroscopy supports the presence of organic preservation. This remarkable preservation is likely the result of several factors such as the favourable antimicrobial and physical shielding properties of Baltic amber as compared to other depositional media, coupled to rapid dehydration of the beetle early in its taphonomic process. We provide evidence that crack-out studies of amber inclusions, although inherently destructive of fossils, are an underutilised method for probing exceptional preservation in deep time
Extraction of active, contaminant degrading enzymes from soil
Get PDFSoil microorganisms play critical roles in the degradation of micro-and nano-pollutants, and the corresponding proteins and enzymes play roles in pollutant recognition, transportation, and degradation. Our ability to study these pathways from soil samples is often complicated by the complex processes involved in extracting proteins from soil matrices. This study aimed to develop a new protein soil extraction protocol that yielded active, intracellular enzymes from the perchlorate degradation pathway, particularly perchlorate reductase. An indirect method, which focused on first separating the cells from the soil matrix, followed by cell lysis and enzyme extraction, was evaluated. The optimized indirect method achieved a final extraction efficiency of the active enzyme and total protein of 15.7 % and 3.3 %, respectively. The final step of separating enzymes from residual soil components resulted in the highest activity and protein losses of 67.7 % ± 14.8 % and 91.8 % ± 1.8 %, respectively. Five buffers, each at different concentrations (0.01 M, 0.05 M, and 0.1 M), were tested to enhance enzyme extraction efficiency. The best extractant requires careful consideration between the highest activity and the quality of the recovered enzymes. Coextraction of humic substances could be minimized by using 0.1 M as compared to 0.01 M and 0.05 M of sodium pyrophosphate; however, this resulted in less recovered activity compared to lower extractant concentrations
Berriasian–Valanginian Geochronology and Carbon-Isotope Stratigraphy of the Yellow Cat Member, Cedar Mountain Formation, Eastern Utah, USA
Get PDFThe Early Cretaceous Yellow Cat Member of the terrestrial Cedar Mountain Formation in Utah, USA. has been interpreted as a “time-rich” unit because of its dinosaur fossils, prominent paleosols, and the results of preliminary chemostratigraphic and geochronologic studies. Herein, we refine prior interpretations with: (1) a new composite C-isotope chemostratigraphic profile from the well-known Utahraptor Ridge dinosaur site, which exhibits δ13C features tentatively interpreted as the Valanginian double-peak carbon isotope excursion (the so-called “Weissert Event”) and some unnamed Berriasian features; and (2) a new cryptotephra zircon eruption age of 135.10 ± 0.30/0.31/0.34 Ma (2σ) derived from the CA-ID-TIMS U-Pb analyses of zircons from a paleosol cryptotephra. Our interpretations of δ13C features on our chemostratigraphic profile, in the context of our new radiometric age, are compatible with at least one prior age model for the “Weissert Event” and the most recent revision of the Cretaceous time scale. Our results also support the interpretation that the Yellow Cat Member records a significant part of Early Cretaceous time
Hyper-palatable foods in elementary school lunches: Availability and contributing factors in a national sample of US public schools
Get PDFBackground
School cafeterias are a major point of influence for child nutrition. United States federal legislation requires the presence of important nutrients in school meals. However, legislation overlooks the potential presence of hyper-palatable foods in school lunches, a hypothesized factor that may influence children’s eating behavior and obesity risk. The study sought to 1) quantify the prevalence of hyper-palatable foods (HPF) served in US elementary school lunches; and 2) determine whether food hyper-palatability varied based on school geographic region (East/Central/West), urbanicity (urban/micropolitan/rural), or meal item (entrée/side/fruit or vegetable).
Methods
Lunch menu data (N = 18 menus; N = 1160 total foods) were collected from a sample of six states that represented geographic regions of the United States (Eastern/Central/Western; Northern/Southern) and that had variability in urbanicity (urban, micropolitan, and rural) within each state. A standardized definition from Fazzino et al (2019) was used to identify HPF in lunch menus.
Results
HPF comprised almost half of foods in school lunches (M = 47%; SD = 5%). Compared to fruit/vegetable items, entrées were >23 times more likely to be hyper-palatable and side dishes were >13 times more likely to be hyper-palatable (p values .05). The majority of entrée and side items contained meat/meat alternatives and/or grains and likely aligned with the US federal reimbursable meal components of meat/meat alternatives and/or grains.
Conclusions and implications
HPF comprised almost half of foods offered in elementary school lunches. Entrées and side items were most likely to be hyper-palatable. US school lunches may be a key point of regular exposure to HPF among young children, a risk factor that may elevate child obesity risk. Public policy regulating HPF in school meals may be needed to protect children’s health