New 19F NMR methodology reveals structures of molecules in complex mixtures of fluorinated compounds.

Although the number of natural fluorinated compounds is very small, fluorinated pharmaceuticals and agrochemicals are numerous. 19F NMR spectroscopy has a great potential for the structure elucidation of fluorinated organic molecules, starting with their production by chemical or chemoenzymatic reactions, through monitoring their structural integrity, to their biotic and abiotic transformation and ultimate degradation in the environment. Additionally, choosing to incorporate 19F into any organic molecule opens a convenient route to study reaction mechanisms and kinetics. Addressing limitations of the existing 19F NMR techniques, we have developed methodology that uses 19F as a powerful spectroscopic spy to study mixtures of fluorinated molecules. The proposed 19F-centred NMR analysis utilises the substantial resolution and sensitivity of 19F to obtain a large number of NMR parameters, which enable structure determination of fluorinated compounds without the need for their separation or the use of standards. Here we illustrate the 19F-centred structure determination process and demonstrate its power by successfully elucidating the structures of chloramination disinfectant by-products of a single mono-fluorinated phenolic compound, which would have been impossible otherwise. This novel NMR approach for the structure elucidation of molecules in complex mixtures represents a major contribution towards the analysis of chemical and biological processes involving fluorinated compounds.

19F-centred NMR analysis of mono-fluorinated compounds.

Addressing limitations of the existing NMR techniques for the structure determination of mono-fluorinated compounds, we have developed methodology that uses 19F as the focal point of this process. The proposed 19F-centred NMR analysis consists of a complementary set of broadband, phase-sensitive NMR experiments that utilise the substantial sensitivity of 19F and its far reaching couplings with 1H and 13C to obtain a large number of NMR parameters. The assembled 1H, 13C and 19F chemical shifts, values of J HF, J HH, and J FC coupling constants and the size of 13C induced 19F isotopic shifts constitute a rich source of information that enables structure elucidation of fluorinated moieties and even complete structures of molecules. Here we introduce the methodology, provide a detailed description of each NMR experiment and illustrate their interpretation using 3-fluoro-3-deoxy-d-glucose. This novel approach performs particularly well in the structure elucidation of fluorinated compounds embedded in complex mixtures, eliminating the need for compound separation or use of standards to confirm the structures. It represents a major contribution towards the analysis of fluorinated agrochemicals and (radio)pharmaceuticals at any point during their lifetime, including preparation, use, biotransformation and biodegradation in the environment. The developed methodology can also assist with the investigations of the stability of fluoroorganics and their pharmacokinetics. Studies of reaction mechanisms using fluorinated molecules as convenient reporters of these processes, will also benefit.

When are fossil fuels displaced? An exploratory inquiry into the role of nuclear electricity production in the displacement of fossil fuels.

We explore how renewable electricity production influences nuclear energy and fossil fuel use in the electricity sector for 109 nations from 1960-2015 and how such patterns change over time. We find that although a one-unit increase in the number of kWh produced from renewable sources does not appear to displace an equivalent number of kWh from fossil fuels, such an increase is associated with an equivalent reduction in the number of kWh drawn from nuclear sources between 1960 and 2015. However, further analyses indicate that there has been a trend toward displacement of fossil fuel sources by renewables, as well as an attenuation of the displacement of nuclear sources by renewables, since the late 1990s in nations with the capacity for nuclear electricity production. These findings suggest that social, political, and economic processes may prevent renewables from being deployed such that they decarbonize the existing electricity grid, especially outside of the 31 nations capable of producing electricity from nuclear energy sources.

High-Resolution Molecular-Level Characterization of a Blanket Bog Peat Profile.

To understand peatland carbon-cycling processes ultimately requires the ability to track changes occurring on the molecular-level. In this study, we profile a peat core taken from the world's largest blanket bog, Flow Country, Scotland, using physicochemical properties, ATR-FTIR, solid/liquid-state NMR, and solid/liquid-state FT-ICR-MS. Air-dried peat and labile and recalcitrant peat extracts, including pore water dissolved organic matter (PW-DOM), are analyzed and the merits of each technique are discussed. Solid-state NMR demonstrated changing distribution of compound classes with core depth and water table, the latter not picked up by IR. Liquid-state NMR and MS both demonstrated variations in molecular composition along the core depth in all phases and extracts. Contrary to previous reports, the composition of PW-DOM varied with depth. Major compounds, some previously unreported, identified by 1D/2D NMR occurred throughout the core, suggesting the existence of hot spots of microbial activity/compound accumulation. Offering complementary views, the techniques provided evidence of gradual molecular level changes with age, zonation due to the water table, and hot spots due to microbial activity. This study provides new insights into the molecular signatures of peat layers and establishes the foundation for examining peat function and health at the molecular-level.

Molecular Tagging for the Molecular Characterization of Natural Organic Matter.

Natural organic matter (NOM) is the product of microbial and abiotic decay of plant and animal remains in terrestrial and aquatic ecosystems. On a molecular level, NOM is a complex mixture of organic molecules, of which the vast majority of structures are unknown. By identifying these molecules, our understanding of the many functions of NOM could be greatly enhanced. However, given that they are chromatographically inseparable and number in the thousands, traditional analytical techniques have proven unable to achieve this goal. A promising approach to enumerate functional groups and elucidate molecular structures within NOM is based on a combination of molecular tagging and high resolution spectroscopic techniques, such as nuclear magnetic resonance spectroscopy and mass spectrometry. Molecular tagging involves the selective modification of particular functional groups, inserting nuclei to act as reporters on their surrounding chemical environment. This allows examination of only the tagged molecules within NOM, thereby reducing the complexity of the mixture. In this review, the effectiveness of molecular tagging methods incorporating carbon, silicon, nitrogen, phosphorus, and deuterium into NOM are discussed. Some potential tagging methods which have not yet been applied to NOM are also presented.

Modernizing our way out or digging ourselves in? Reconsidering the impacts of efficiency innovations and affluence on residential energy consumption, 2005-2015.

This study scrutinizes the impacts of efficiency innovations as well as affluence on residential energy consumption, which is a major driver of greenhouse gas emissions. The study draws on the ecological-modernization perspective, which is optimistic about how technological innovations and affluence can help societies overcome environmental challenges associated with production and consumption, and the political-economy perspective, which raises doubts about whether these factors are beneficial to the environment, given their tendency to drive more consumption. Analysis of nationally representative longitudinal data reveals mixed relationships between efficiency innovations and residential energy consumption: while some measures of efficiency innovations, generally those not requiring human-technology interactions, are negatively related to residential energy consumption, others are either unrelated to it or drive more consumption. These findings suggest efficiency innovations offer only minimal opportunities for conserving energy, and may depend on the nature of the innovation. Raising doubts about the potential for rising affluence to promote environmental protection, this study reveals positive relationships between our measures of affluence and residential energy consumption.

Social science perspectives on drivers of and responses to global climate change.

This article provides a review of recent anthropological, archeological, geographical, and sociological research on anthropogenic drivers of climate change, with a particular focus on drivers of carbon emissions, mitigation and adaptation. The four disciplines emphasize cultural, economic, geographic, historical, political, and social-structural factors to be important drivers of and responses to climate change. Each of these disciplines has unique perspectives and makes noteworthy contributions to our shared understanding of anthropogenic drivers, but they also complement one another and contribute to integrated, multidisciplinary frameworks. The article begins with discussions of research on temporal dimensions of human drivers of carbon emissions, highlighting interactions between long-term and near-term drivers. Next, descriptions of the disciplines' contributions to the understanding of mitigation and adaptation are provided. It concludes with a summary of key lessons offered by the four disciplines as well as suggestions for future research. This article is categorized under: Climate Economics > Economics and Climate Change.

Aquaculture and the displacement of fisheries captures.

In modern aquaculture, animal-production technology is used to increase aquatic food sources. Such controlled rearing of seafood can, in principle, shift the pressure off wild stocks and aquatic ecosystems by reducing fishing activities, which may advance marine conservation goals. We examined resource displacement-the reduced consumption of a resource due to its replacement with a more environmentally benign substitute-in fisheries. We employed panel regression techniques in an analysis of time-series data from 1970 through 2014 to assess the extent to which aquaculture production displaced fisheries captures for all nations for which data were available. We estimated 9 models to assess whether aquaculture production suppresses captures once other factors related to demand have been controlled for. Only 1 model predicted significant suppression of fisheries captures associated with aquaculture systems within nations over time. These results suggest that global aquaculture production does not substantially displace fisheries capture; instead, aquaculture production largely supplements fisheries capture.

La Acuacultura y el Desplazamiento de Capturas de las Pesquerías Resumen En la acuacultura moderna, la tecnología de producción animal se usa para incrementar las fuentes acuáticas de alimento. Tal crianza controlada de peces puede, en principio, modificar la presión que afecta los stocks silvestres y los ecosistemas acuáticos al reducir las actividades de pesca, lo que podría acercarnos a la obtención de las metas de conservación. Examinamos el desplazamiento de recursos - el consumo reducido de un recurso debido a su reemplazo con un sustituto más benigno con el ambiente - en las pesquerías. Empleamos técnicas de regresión de paneles en un análisis de datos de series de tiempo de 1970 a 2014 para evaluar hasta dónde ha llegado el desplazamiento de las capturas de las pesquerías en todos los países que tenían datos disponibles. Estimamos nueve modelos para evaluar si la producción de la acuacultura suprime las capturas una vez que otros factores relacionados con la demanda han sido controlados. Solamente un modelo pronosticó la supresión de las capturas de las pesquerías asociadas con los sistemas de acuacultura en los países a lo largo del tiempo. Estos resultados sugieren que la producción acuícola no desplaza sustancialmente la captura de las pesquerías; en su lugar, la producción acuícola complementa en gran parte a estas capturas.

Asymmetric relationship of urbanization and CO2 emissions in less developed countries.

Understanding the relationship between carbon dioxide (CO2) emissions and the urbanization of national populations has been a key concern for environmental scholars for several decades. Although sophisticated modeling techniques have been developed to explore the connection between increases in urban populations and CO2 emissions, none has attempted to assess whether declines in urbanization have an effect on emissions that is not symmetrical with that of growth in urbanization. The present study uses panel data on CO2 emissions and the percentage of individuals living in urban areas, as well as a variety of other structural factors, for less-developed countries from 1960-2010, to empirically assess whether the effect of growth in urban populations on emissions is symmetrical with the effect of decline. Findings indicate that the effect of growth/decline in urban populations on CO2 emissions is asymmetrical, where a decline in urbanization reduces emissions to a much greater degree than urbanization increases emissions. We hypothesize that this is at least in part because deurbanization is connected with disruptions to the production and distribution of goods and services and/or access to electricity and other energy sources. Our finding suggests that not only the absolute level of urbanization of nations matters for emissions, but also how the patterns of migration between rural and urban areas change over time. Future research should be mindful of the processes behind deurbanization when exploring socioeconomic drivers of CO2 emissions.

Nitrogen extraction potential of wild and cultured bivalves harvested from nearshore waters of Cape Cod, USA.

As nitrogen entering coastal waters continues to be an issue, much attention has been generated to identify potential options that may help alleviate this stressor to estuaries, including the propagation of bivalves to remove excess nitrogen. Oysters (Crassostrea virginica) and quahogs (Mercenaria mercenaria) from numerous Cape Cod, MA, (USA) sources were analyzed for nitrogen content stored in tissues that would represent a net removal of nitrogen from a water body if harvested. Results showed local oysters average 0.69% nitrogen by total dry weight (mean 0.28gN/animal) and quahogs average 0.67% nitrogen by total dry weight (mean 0.22gN/animal); however, these values did vary by season and to a lesser extent by location or grow-out method. The differences in nitrogen content were largely related to the mass of shell or soft tissue. Nitrogen isotope data indicate shellfish from certain water bodies in the region are incorporating significant amounts of nitrogen from anthropogenic sources.

The human dimensions of climate change: A micro-level assessment of views from the ecological modernization, political economy and human ecology perspectives.

Understanding the manifold human and physical dimensions of climate change has become an area of great interest to researchers in recent decades. Using a U.S. nationally-representative data set and drawing on the ecological modernization, political economy, and human ecology perspectives, this study examines the impacts of energy efficiency technologies, affluence, household demographics, and biophysical characteristics on residential CO2 emissions. Overall, the study provides mixed support for the ecological modernization perspective. While several findings are consistent with the theory's expectation that modern societies can harness technology to mitigate human impacts on the environment, others directly contradict it. Also, the theory's prediction of an inverted U-shaped relationship between affluence and environmental impacts is contradicted. The evidence is somewhat more supportive of the political economy and human ecology perspectives, with affluence, some indicators of technology, household demographics, and biophysical characteristics emerging as important drivers of residential CO2 emissions.

Life satisfaction across nations: the effects of women's political status and public priorities.

Feminist scholars suggest that improving the quality of life of individuals living in nations around the world may be more readily achieved by increasing women's political power and by reorienting public-policy priorities, than by focusing primarily on economic growth. These considerations raise the question of which characteristics of societies are associated with the quality of life of the people in those societies. Here, we address this issue empirically by statistically analyzing cross-national data. We assess the effects of gender equality in the political sphere, as well as a variety of other factors, on the subjective well-being of nations, as indicated by average self-reported levels of life satisfaction. We find that people report the highest levels of life satisfaction in nations where women have greater political representation, where military spending is low, and where health care spending is high, controlling for a variety of other factors. GDP per capita, urbanization, and natural resource exploitation are not clearly associated with life satisfaction. These findings suggest that nations may be able to improve the subjective quality of life of people without increasing material wealth or natural resource consumption by increasing gender equality in politics and changing public spending priorities.

Women's status and carbon dioxide emissions: A quantitative cross-national analysis.

Global climate change is one of the most severe problems facing societies around the world. Very few assessments of the social forces that influence greenhouse gas emissions have examined gender inequality. Empirical research suggests that women are more likely than men to support environmental protection. Various strands of feminist theory suggest that this is due to women's traditional roles as caregivers, subsistence food producers, water and fuelwood collectors, and reproducers of human life. Other theorists argue that women's status and environmental protection are linked because the exploitation of women and the exploitation of nature are interconnected processes. For these theoretical and empirical reasons, we hypothesize that in societies with greater gender equality there will be relatively lower impacts on the environment, controlling for other factors. We test this hypothesis using quantitative analysis of cross-national data, focusing on the connection between women's political status and CO(2) emissions per capita. We find that CO(2) emissions per capita are lower in nations where women have higher political status, controlling for GDP per capita, urbanization, industrialization, militarization, world-system position, foreign direct investment, the age dependency ratio, and level of democracy. This finding suggests that efforts to improve gender equality around the world may work synergistically with efforts to curtail global climate change and environmental degradation more generally.

Residualization is not the answer: Rethinking how to address multicollinearity.

Here I show that a commonly used procedure to address problems stemming from collinearity and multicollinearity among independent variables in regression analysis, "residualization", leads to biased coefficient and standard error estimates and does not address the fundamental problem of collinearity, which is a lack of information. I demonstrate this using visual representations of collinearity, hypothetical experimental designs, and analyses of both artificial and real world data. I conclude by noting the importance of examining methodological practices to ensure that their validity can be established based on rational criteria.

Critical materialism: science, technology, and environmental sustainability.

There are widely divergent views on how science and technology are connected to environmental problems. A view commonly held among natural scientists and policy makers is that environmental problems are primarily technical problems that can be solved via the development and implementation of technological innovations. This technologically optimistic view tends to ignore power relationships in society and the political-economic order that drives environmental degradation. An opposed view, common among postmodernist and poststructuralist scholars, is that the emergence of the scientific worldview is one of the fundamental causes of human oppression. This postmodernist view rejects scientific epistemology and often is associated with an anti-realist stance, which ultimately serves to deny the reality of environmental problems, thus (unintentionally) abetting right-wing efforts to scuttle environmental protection. We argue that both the technologically optimistic and the postmodernist views are misguided, and both undermine our ability to address environmental crises. We advocate the adoption of a critical materialist stance, which recognizes the importance of natural science for helping us to understand the world while also recognizing the social embeddedness of the scientific establishment and the need to challenge the manipulation of science by the elite.

Economic growth and marine biodiversity: influence of human social structure on decline of marine trophic levels.

We assessed the effects of economic growth, urbanization, and human population size on marine biodiversity. We used the mean trophic level (MTL) of marine catch as an indicator of marine biodiversity and conducted cross-national time-series analyses (1960-2003) of 102 nations to investigate human social influences on fish catch and trends in MTL. We constructed path models to examine direct and indirect effects relating to marine catch and MTL. Nations' MTLs declined with increased economic growth, increased urbanization, and increased population size, in part because of associated increased catch. These findings contradict the environmental Kuznets curve hypothesis, which claims that economic modernization will reduce human impact on the environment. To make informed decisions on issues of marine resource management, policy makers, nonprofit entities, and professional societies must recognize the need to include social analyses in overall conservation-research strategies. The challenge is to utilize the socioeconomic and ecological research in the service of a comprehensive marine-conservation movement.

Tracking the anthropogenic drivers of ecological impacts.

Despite the pivotal role human factors (anthropogenic drivers) are presumed to play in global environmental change, substantial uncertainties and contradictory conclusions about them continue. We attempt to further discipline the human factors issue by estimating the effects of two anthropogenic drivers, population and affluence, on a wide variety of global environmental impacts, including greenhouse gas emissions, emissions of ozone depleting substances, and the ecological footprint. Population proportionately increases all types of impacts examined. Affluence typically increases impacts, but the specific effect depends on the type of impact. These findings refocus attention on population and material affluence as principal threats to sustainability and challenge predictions of an ameliorating effect of rising affluence on impacts.