Introducing original methods for integrating sociocultural and discourse studies into science and engineering education, this book provides a much-needed framework for how to conduct qualitative ...research in this field. The three dimensions of learning identified in the Next Generation Science Standards (NGSS) create a need for research methods that examine the sociocultural components of science education. With cutting-edge studies and examples consistent with the NGSS, this book offers comprehensive research methods for integrating discourse and sociocultural practices in science and engineering education and provides key tools for applying this framework for students, pre-service teachers, scholars, and researchers.
Dietary restriction with adequate nutrition is the gold standard for delaying ageing and extending healthspan and lifespan in diverse species, including rodents and non-human primates. In this ...Review, we discuss the effects of dietary restriction in these mammalian model organisms and discuss accumulating data that suggest that dietary restriction results in many of the same physiological, metabolic and molecular changes responsible for the prevention of multiple ageing-associated diseases in humans. We further discuss how different forms of fasting, protein restriction and specific reductions in the levels of essential amino acids such as methionine and the branched-chain amino acids selectively impact the activity of AKT, FOXO, mTOR, nicotinamide adenine dinucleotide (NAD
), AMP-activated protein kinase (AMPK) and fibroblast growth factor 21 (FGF21), which are key components of some of the most important nutrient-sensing geroprotective signalling pathways that promote healthy longevity.
Low-molecular-weight hydrocarbons in natural hydrothermal fluids have been attributed to abiogenic production by Fischer-Tropsch type (FTT) reactions, although clear evidence for such a process has ...been elusive. Here, we present concentration, and stable and radiocarbon isotope, data from hydrocarbons dissolved in hydrogen-rich fluids venting at the ultramafic-hosted Lost City Hydrothermal Field. A distinct "inverse" trend in the stable carbon and hydrogen isotopic composition of C₁ to C₄ hydrocarbons is compatible with FTT genesis. Radiocarbon evidence rules out seawater bicarbonate as the carbon source for FTT reactions, suggesting that a mantle-derived inorganic carbon source is leached from the host rocks. Our findings illustrate that the abiotic synthesis of hydrocarbons in nature may occur in the presence of ultramafic rocks, water, and moderate amounts of heat.
Carbonate‐brucite chimneys are a characteristic of low‐ to moderate‐temperature, ultramafic‐hosted alkaline hydrothermal systems, such as the Lost City hydrothermal field located on the Atlantis ...Massif at 30°N near the Mid‐Atlantic Ridge. These chimneys form as a result of mixing between warm, serpentinization‐derived vent fluids and cold seawater. Previous work has documented the evolution in mineralogy and geochemistry associated with the aging of the chimneys as hydrothermal activity wanes. However, little is known about spatial heterogeneities within and among actively venting chimneys. New mineralogical and geochemical data (87Sr/86Sr and stable C, O, and clumped isotopes) indicate that the brucite and calcite precipitate at elevated temperatures in vent fluid‐dominated domains in the interior of chimneys. Exterior zones dominated by seawater are brucite‐poor and aragonite is the main carbonate mineral. Carbonates record mostly out of equilibrium oxygen and clumped isotope signatures due to rapid precipitation upon vent fluid‐seawater mixing. On the other hand, the carbonates precipitate closer to carbon isotope equilibrium, with dissolved inorganic carbon in seawater as the dominant carbon source and have δ13C values within the range of marine carbonates. Our data suggest that calcite is a primary mineral in the active hydrothermal chimneys and does not exclusively form as a replacement of aragonite during later alteration with seawater. Elevated formation temperatures and lower 87Sr/86Sr relative to aragonite in the same sample suggest that calcite may be the first carbonate mineral to precipitate.
Plain Language Summary
At the Lost City hydrothermal field, warm alkaline fluids are discharging out of uplifted mantle rocks. When vent fluids mix with seawater at the seafloor, carbonate and brucite minerals form spectacular towers up to 60 m high. Systems like Lost City are important because the reaction between water and rocks provides carbon and energy sources for microbial life. However, we still do not fully understand what controls the mineralogy and geochemistry of the Lost City hydrothermal chimneys. In this paper, we suggest that the extent of mixing between the hydrothermal fluids and seawater influences the mineralogy and geochemistry of the chimneys. Calcite, which was previously thought to form only during alteration of aragonite by seawater, can also form during seawater‐hydrothermal fluid mixing. Both calcite and brucite form in the interior of the chimneys where vent fluid is more dominant. Aragonite, on the other hand, forms in the exterior of the structures from seawater‐rich fluids. Lastly, because minerals precipitate rapidly during fluid mixing, the stable isotope geochemistry of the carbonates mostly records the composition and temperature of seawater and not the mixed fluid. Thus, care should be exercised in interpreting mineral geochemical data from similar systems.
Key Points
The mineralogy and geochemistry of Lost City chimneys are controlled by the extent of mixing between hydrothermal fluids and seawater
Brucite and calcite precipitate in vent fluid dominated zones while aragonite forms in the exterior of the structures in seawater‐rich zones
Carbonates precipitate in isotopic disequilibrium and record the O and C stable isotope composition of seawater dissolved inorganic carbon
The abundance of different SSU rRNA ("16S") gene sequences in environmental samples is widely used in studies of microbial ecology as a measure of microbial community structure and diversity. ...However, the genomic copy number of the 16S gene varies greatly - from one in many species to up to 15 in some bacteria and to hundreds in some microbial eukaryotes. As a result of this variation the relative abundance of 16S genes in environmental samples can be attributed both to variation in the relative abundance of different organisms, and to variation in genomic 16S copy number among those organisms. Despite this fact, many studies assume that the abundance of 16S gene sequences is a surrogate measure of the relative abundance of the organisms containing those sequences. Here we present a method that uses data on sequences and genomic copy number of 16S genes along with phylogenetic placement and ancestral state estimation to estimate organismal abundances from environmental DNA sequence data. We use theory and simulations to demonstrate that 16S genomic copy number can be accurately estimated from the short reads typically obtained from high-throughput environmental sequencing of the 16S gene, and that organismal abundances in microbial communities are more strongly correlated with estimated abundances obtained from our method than with gene abundances. We re-analyze several published empirical data sets and demonstrate that the use of gene abundance versus estimated organismal abundance can lead to different inferences about community diversity and structure and the identity of the dominant taxa in microbial communities. Our approach will allow microbial ecologists to make more accurate inferences about microbial diversity and abundance based on 16S sequence data.
•Butts are heterogeneously distributed, mean of 2.7m−2, max of 48m−2 in study area.•Quick nicotine elution from butts in standing and rainwater.•Cigarette butts are hazardous waste according to EU ...thresholds.•Cigarette butts represent a threat to urban water quality and drinking water.•Recommendation of public education campaign to reduce littered butts.
The effect of nicotine from littered cigarette butts on the quality of urban water resources has yet to be investigated. This two-part study addresses the spatial variation, seasonal dynamics and average residence time of littered cigarette butts in public space, as well as the release of nicotine from cigarette butts to run-off in urban areas during its residence time. Thereby, we tested two typical situations: release to standing water in a puddle and release during alternating rainfall and drying. The study took place in Berlin, Germany, a city which completely relies on its own water resources to meet its drinking water demand. Nine typical sites located in a central district, each divided into 20 plots were studied during five sampling periods between May 2012 and February 2013. The nicotine release from standardized cigarette butts prepared with a smoking machine was examined in batch and rainfall experiments.
Littered cigarette butts are unevenly distributed among both sites and plots. The average butt concentration was 2.7m−2 (SD=0.6m−2, N=862); the maximum plot concentration was 48.8buttsm−2. This heterogeneity is caused by preferential littering (gastronomy, entrances, bus stops), redistribution processes such as litter removal (gastronomy, shop owners), and the increased accumulation in plots protected from mechanized street sweeping (tree pits, bicycle stands). No significant seasonal variation of cigarette butt accumulation was observed. On average, cigarette butt accumulation is characterized by a 6days cadence due to the rhythm and effectiveness of street sweeping (mean weekly butt accumulation rate=0.18m−2d−1; SD=0.15m−1). Once the butt is exposed to standing water, elution of nicotine occurs rapidly. Standardized butts released 7.3mgg−1 nicotine in a batch experiment (equivalent to 2.5mgL−1), 50% of which occurred within the first 27min. In the rainfall experiment, the cumulative nicotine release from fifteen consecutive precipitation events (each 1.4mm) was 3.8mgg−1, with 47% during the first event. According to these results, one cigarette butt may contaminate an amount of 1000L water to concentrations above the predicted no effect concentration (PNEC) of only 2.4×10−3mgL−1 (Valcárcel et al., 2011). Given the continuous littering of cigarette butts, and the rapid release of nicotine, cigarette butts are assessed to be a relevant threat to the quality of urban waters and consequently to drinking water.
Space weather describes the way in which the Sun, and conditions in space more generally, impact human activity and technology both in space and on the ground. It is now well understood that space ...weather represents a significant threat to infrastructure resilience, and is a source of risk that is wide‐ranging in its impact and the pathways by which this impact may occur. Although space weather is growing rapidly as a field, work rigorously assessing the overall economic cost of space weather appears to be in its infancy. Here, we provide an initial literature review to gather and assess the quality of any published assessments of space weather impacts and socioeconomic studies. Generally speaking, there is a good volume of scientific peer‐reviewed literature detailing the likelihood and statistics of different types of space weather phenomena. These phenomena all typically exhibit “power‐law” behavior in their severity. The literature on documented impacts is not as extensive, with many case studies, but few statistical studies. The literature on the economic impacts of space weather is rather sparse and not as well developed when compared to the other sections, most probably due to the somewhat limited data that are available from end‐users. The major risk is attached to power distribution systems and there is disagreement as to the severity of the technological footprint. This strongly controls the economic impact. Consequently, urgent work is required to better quantify the risk of future space weather events.
Cyclin-dependent kinase 9 (CDK9), an important regulator of transcriptional elongation, is a promising target for cancer therapy, particularly for cancers driven by transcriptional dysregulation. We ...characterized NVP-2, a selective ATP-competitive CDK9 inhibitor, and THAL-SNS-032, a selective CDK9 degrader consisting of a CDK-binding SNS-032 ligand linked to a thalidomide derivative that binds the E3 ubiquitin ligase Cereblon (CRBN). To our surprise, THAL-SNS-032 induced rapid degradation of CDK9 without affecting the levels of other SNS-032 targets. Moreover, the transcriptional changes elicited by THAL-SNS-032 were more like those caused by NVP-2 than those induced by SNS-032. Notably, compound washout did not significantly reduce levels of THAL-SNS-032-induced apoptosis, suggesting that CDK9 degradation had prolonged cytotoxic effects compared with CDK9 inhibition. Thus, our findings suggest that thalidomide conjugation represents a promising strategy for converting multi-targeted inhibitors into selective degraders and reveal that kinase degradation can induce distinct pharmacological effects compared with inhibition.
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•Reducing specific dietary amino acids can improve metabolic health parameters.•Amino acid restriction may promote metabolic health via multiple molecular mechanisms.•The sexually ...dimorphic response to methionine deprivation may underpin some amino acid-mediated molecular effects.
Although the beneficial effects of calorie restriction (CR) on health and aging were first observed a century ago, the specific macronutrients and molecular processes that mediate the effect of CR have been heavily debated. Recently, it has become clear that dietary protein plays a key role in regulating both metabolic health and longevity, and that both the quantity and quality - the specific amino acid composition - of dietary protein mediates metabolic health. Here, we discuss recent findings in model organisms ranging from yeast to mice and humans regarding the influence of dietary protein as well as specific amino acids on metabolic health, and the physiological and molecular mechanisms which may mediate these effects. We then discuss recent findings which suggest that the restriction of specific dietary amino acids may be a potent therapy to treat or prevent metabolic syndrome. Finally, we discuss the potential for dietary restriction of specific amino acids – or pharmaceuticals which harness these same mechanisms – to promote healthy aging.
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