Showing papers by "University of New Hampshire published in 2012"
Stockholm University1, University of New Hampshire2, University of Alaska Fairbanks3, Scott Polar Research Institute4, Canadian Hydrographic Service5, Norwegian Mapping Authority6, University Centre in Svalbard7, Alfred Wegener Institute for Polar and Marine Research8, Science Applications International Corporation9, Johns Hopkins University Applied Physics Laboratory10, University of Barcelona11, University of New Brunswick12, University of Hawaii at Manoa13, University of Bergen14, Geological Survey of Denmark and Greenland15, Geological Survey of Canada16, California Institute of Technology17, British Oceanographic Data Centre18
TL;DR: The International Bathymetric Chart of the Arctic Ocean (IBCAO) released its first gridded bathymetric compilation in 1999 as discussed by the authors, which has since supported a wide range of Arc...
Abstract: The International Bathymetric Chart of the Arctic Ocean (IBCAO) released its first gridded bathymetric compilation in 1999. The IBCAO bathymetric portrayals have since supported a wide range of Arc ...
977Â citations
TL;DR: It is shown that nutrient levels commonly associated with coastal eutrophication increased above-ground leaf biomass, decreased the dense, below-ground biomass of bank-stabilizing roots, and increased microbial decomposition of organic matter, demonstrating that nutrient enrichment can be a driver of salt marsh loss.
Abstract: A nine-year whole-ecosystem experiment demonstrates that nutrient enrichment, a global problem in coastal ecosystems, can be a driver of salt-marsh loss. Salt marshes provide important ecosystem services such as storm protection for coastal cities, nutrient removal and carbon sequestration, but despite protective measures these ecosystems are in decline. Nine years of data from a whole-ecosystem nutrient-enrichment experiment now demonstrate that current levels of coastal nutrient loading can alter key salt-marsh-ecosystem properties, leading to the collapse of creek banks and, ultimately, the conversion of salt marsh into mudflat. The potential deterioration of coastal marshes owing to eutrophication adds another dimension to the challenge of managing nitrogen while meeting food-production demands in the twenty-first century. Salt marshes are highly productive coastal wetlands that provide important ecosystem services such as storm protection for coastal cities, nutrient removal and carbon sequestration. Despite protective measures, however, worldwide losses of these ecosystems have accelerated in recent decades1. Here we present data from a nine-year whole-ecosystem nutrient-enrichment experiment. Our study demonstrates that nutrient enrichment, a global problem for coastal ecosystems2,3,4, can be a driver of salt marsh loss. We show that nutrient levels commonly associated with coastal eutrophication increased above-ground leaf biomass, decreased the dense, below-ground biomass of bank-stabilizing roots, and increased microbial decomposition of organic matter. Alterations in these key ecosystem properties reduced geomorphic stability, resulting in creek-bank collapse with significant areas of creek-bank marsh converted to unvegetated mud. This pattern of marsh loss parallels observations for anthropogenically nutrient-enriched marshes worldwide, with creek-edge and bay-edge marsh evolving into mudflats and wider creeks5,6,7. Our work suggests that current nutrient loading rates to many coastal ecosystems have overwhelmed the capacity of marshes to remove nitrogen without deleterious effects. Projected increases in nitrogen flux to the coast, related to increased fertilizer use required to feed an expanding human population, may rapidly result in a coastal landscape with less marsh, which would reduce the capacity of coastal regions to provide important ecological and economic services.
844Â citations
Harvard University1, University of Montana2, McMaster University3, Environment Canada4, Ohio State University5, Auburn University6, University of Toronto7, Centre national de la recherche scientifique8, Pennsylvania State University9, University of Wisconsin-Madison10, University of Illinois at Urbana–Champaign11, Indiana University12, Virginia Commonwealth University13, University of Alberta14, United States Forest Service15, Laval University16, Queen's University17, Cooperative Institute for Research in Environmental Sciences18, Oak Ridge National Laboratory19, Princeton University20, University of Colorado Boulder21, Ensenada Center for Scientific Research and Higher Education22, Ghent University23, University of New Hampshire24, University of California, Los Angeles25
TL;DR: In this article, the authors evaluate the representation of phenology, and the associated seasonality of ecosystem-scale CO2 exchange, in 14 models participating in the North American Carbon Program Site Synthesis.
Abstract: Phenology, by controlling the seasonal activity of vegetation on the land surface, plays a fundamental role in regulating photosynthesis and other ecosystem processes, as well as competitive interactions and feedbacks to the climate system. We conducted an analysis to evaluate the representation of phenology, and the associated seasonality of ecosystem-scale CO2 exchange, in 14 models participating in the North American Carbon Program Site Synthesis. Model predictions were evaluated using long-term measurements (emphasizing the period 2000–2006) from 10 forested sites within the AmeriFlux and Fluxnet-Canada networks. In deciduous forests, almost all models consistently predicted that the growing season started earlier, and ended later, than was actually observed; biases of 2 weeks or more were
578Â citations
TL;DR: It was found that the majority of replications in psychology journals reported similar findings to their original studies (i.e., they were successful replications), however, replications were significantly less likely to be successful when there was no overlap in authorship between the original and replicating articles.
Abstract: Recent controversies in psychology have spurred conversations about the nature and quality of psychological research. One topic receiving substantial attention is the role of replication in psychological science. Using the complete publication history of the 100 psychology journals with the highest 5-year impact factors, the current article provides an overview of replications in psychological research since 1900. This investigation revealed that roughly 1.6% of all psychology publications used the term replication in text. A more thorough analysis of 500 randomly selected articles revealed that only 68% of articles using the term replication were actual replications, resulting in an overall replication rate of 1.07%. Contrary to previous findings in other fields, this study found that the majority of replications in psychology journals reported similar findings to their original studies (i.e., they were successful replications). However, replications were significantly less likely to be successful when there was no overlap in authorship between the original and replicating articles. Moreover, despite numerous systemic biases, the rate at which replications are being published has increased in recent decades.
565Â citations
TL;DR: In this paper, a metadata analysis of 563 direct gas tracer release experiments was conducted to examine scaling laws for the gas transfer velocity and the product of stream slope and velocity, which is in alignment with theory on stream energy dissipation.
Abstract: Scaling is an integral component of ecology and earth science. To date, the ability to determine the importance of air – water gas exchange across large spatial scales is hampered partly by our ability to scale the gas transfer velocity and stream hydraulics. Here we report on a metadata analysis of 563 direct gas tracer release experiments that examines scaling laws for the gas transfer velocity. We found that the gas transfer velocity scales with the product of stream slope and velocity, which is in alignment with theory on stream energy dissipation. In addition to providing equations that predict the gas transfer velocity based on stream hydraulics, we used our hydraulic data set to report a new set of hydraulic exponents and coefficients that allow the prediction of stream width, depth, and velocity based on discharge. Finally, we report a new table of gas Schmidt number dependencies to allow researchers to estimate a gas transfer velocity using our equation for many gasses of interest.
490Â citations
TL;DR: National estimates of youth involved in sexting in the past year suggest that appearing in, creating, or receiving sexual images is far from being a normative behavior for youth.
Abstract: Objectives: To obtain national estimates of youth involved in sexting in the past year (the transmission via cell phone, the Internet, and other electronic media of sexual images), as well as provide details of the youth involved and the nature of the sexual images. Methods: The study was based on a cross-sectional national telephone survey of 1560 youth Internet users, ages 10 through 17. Results: Estimates varied considerably depending on the nature of the images or videos and the role of the youth involved. Two and one-half percent of youth had appeared in or created nude or nearly nude pictures or videos. However, this percentage is reduced to 1.0% when the definition is restricted to only include images that were sexually explicit (ie, showed naked breasts, genitals, or bottoms). Of the youth who participated in the survey, 7.1% said they had received nude or nearly nude images of others; 5.9% of youth reported receiving sexually explicit images. Few youth distributed these images. Conclusions: Because policy debates on youth sexting behavior focus on concerns about the production and possession of illegal child pornography, it is important to have research that collects details about the nature of the sexual images rather than using ambiguous screening questions without follow-ups. The rate of youth exposure to sexting highlights a need to provide them with information about legal consequences of sexting and advice about what to do if they receive a sexting image. However, the data suggest that appearing in, creating, or receiving sexual images is far from being a normative behavior for youth.
470Â citations
TL;DR: The results indicate that gcc from different digital cameras can be used for comparing the timing of key phenological events across sites, and advocate the use of gcc for phenological research.
466Â citations
TL;DR: This article measured POXC across a wide range of soil types, ecosystems, and geographic areas (12 studies, 53 total sites, = 1379) to determine the relationship between POXc and POC, microbial biomass C (MBC), and soil organic C (SOC) fractions, and determine the relative sensitivity as a labile soil C metric across a range of environmental and management conditions.
Abstract: Permanganate oxidizable C (POXC; i.e., active C) is a relatively new method that can quantify labile soil C rapidly and inexpensively. Despite limited reports of positive correlations with particulate organic C (POC), microbial biomass C (MBC), and other soil C fractions, little is known about what soil fractions POXC most closely reflects. We measured POXC across a wide range of soil types, ecosystems, and geographic areas (12 studies, 53 total sites, = 1379) to: (i) determine the relationship between POXC and POC, MBC and soil organic C (SOC) fractions, and (ii) determine the relative sensitivity of POXC as a labile soil C metric across a range of environmental and management conditions. Permanganate oxidizable C was significantly related to POC, MBC, and SOC, and these relationships were strongest when data were analyzed by individual studies. Permanganate oxidizable C was more closely related to smaller-sized (53–250 μm) than larger POC fractions (250–2000 μm), and more closely related to heavier (>1.7 g cm) than lighter POC fractions, indicating that it reflects a relatively processed pool of labile soil C. Compared with POC, MBC, or SOC, POXC demonstrated greater sensitivity to changes in management or environmental variation in 42% of the significant experimental factors examined across the 12 studies. Our analysis demonstrates the usefulness of POXC in quickly and inexpensively assessing changes in the labile soil C pool.
450Â citations
TL;DR: Despite a promising outlook, the field of eukaryotic marker gene surveys faces significant challenges: how to generate data that are most useful to the community, especially in the face of evolving sequencing technologies and bioinformatics pipelines, and how to incorporate an expanding number of target genes.
Abstract: Microscopic eukaryotes are abundant, diverse and fill critical ecological roles across every ecosystem on Earth, yet there is a well-recognized gap in understanding of their global biodiversity. Fundamental advances in DNA sequencing and bioinformatics now allow accurate en masse biodiversity assessments of microscopic eukaryotes from environmental samples. Despite a promising outlook, the field of eukaryotic marker gene surveys faces significant challenges: how to generate data that are most useful to the community, especially in the face of evolving sequencing technologies and bioinformatics pipelines, and how to incorporate an expanding number of target genes.
416Â citations
TL;DR: Climate may primarily influence δ15N patterns in soils and plants by determining the primary loss mechanisms and which types of mycorrhizal fungi and associated vegetation dominate across climatic gradients.
Abstract: Contents
Summary 367
I. Introduction 367
II. Background on isotopes 368
III. Patterns of soil δ15N 370
IV. Patterns of fungal δ15N 372
V. Biochemical basis for the influence of fungi on δ15N patterns in plant–soil systems 373
VI. Patterns of δ15N in plant and fungal culture studies 374
VII. Mycoheterotrophic and parasitic plants 375
VIII. Patterns of foliar δ15N in autotrophic plants 376
IX. Controls over plant δ15N 377
X. Conclusions and research needs 378
Acknowledgements 379
References 379
Summary
In this review, we synthesize field and culture studies of the 15N/14N (expressed as δ15N) of autotrophic plants, mycoheterotrophic plants, parasitic plants, soil, and mycorrhizal fungi to assess the major controls of isotopic patterns. One major control for plants and fungi is the partitioning of nitrogen (N) into either 15N-depleted chitin, ammonia, or transfer compounds or 15N-enriched proteinaceous N. For example, parasitic plants and autotrophic hosts are similar in δ15N (with no partitioning between chitin and protein), mycoheterotrophic plants are higher in δ15N than their fungal hosts, presumably with preferential assimilation of fungal protein, and autotrophic, mycorrhizal plants are lower in 15N than their fungal symbionts, with saprotrophic fungi intermediate, because mycorrhizal fungi transfer 15N-depleted ammonia or amino acids to plants. Similarly, nodules of N2-fixing bacteria transferring ammonia are often higher in δ15N than their plant hosts. N losses via denitrification greatly influence bulk soil δ15N, whereas δ15N patterns within soil profiles are influenced both by vertical patterns of N losses and by N transfers within the soil–plant system. Climate correlates poorly with soil δ15N; climate may primarily influence δ15N patterns in soils and plants by determining the primary loss mechanisms and which types of mycorrhizal fungi and associated vegetation dominate across climatic gradients.
343Â citations
TL;DR: It seems clear that mosses need to be incorporated into models as one or more plant functional types, but more empirical work is needed to determine how to best aggregate species.
Abstract: Summary Mosses in northern ecosystems are ubiquitous components of plant communities, and strongly influence nutrient, carbon and water cycling. We use literature review, synthesis and model simulations to explore the role of mosses in ecological stability and resilience. Moss community responses to disturbance showed all possible responses (increases, decreases, no change) within most disturbance categories. Simulations from two process-based models suggest that northern ecosystems would need to experience extreme perturbation before mosses were eliminated. But simulations with two other models suggest that loss of moss will reduce soil carbon accumulation primarily by influencing decomposition rates and soil nitrogen availability. It seems clear that mosses need to be incorporated into models as one or more plant functional types, but more empirical work is needed to determine how to best aggregate species. We highlight several issues that have not been adequately explored in moss communities, such as functional redundancy and singularity, relationships between response and effect traits, and parameter vs conceptual uncertainty in models. Mosses play an important role in several ecosystem processes that play out over centuries – permafrost formation and thaw, peat accumulation, development of microtopography – and there is a need for studies that increase our understanding of slow, long-term dynamical processes. Contents Summary 49
TL;DR: It is found that during decomposition, decomposer community characteristics regulate changes in litter chemistry, which could influence the functionality of litter-derived soil organic matter (SOM) and the turnover and stabilisation of soil C.
Abstract: The chemical complexity of decomposing plant litter is a central feature shaping the terrestrial carbon (C) cycle, but explanations of the origin of this complexity remain contentious. Here, we ask: How does litter chemistry change during decomposition, and what roles do decomposers play in these changes? During a long-term (730 days) litter decomposition experiment, we tracked concurrent changes in decomposer community structure and function and litter chemistry using high-resolution molecular techniques. Contrary to the current paradigm, we found that the chemistry of different litter types diverged, rather than converged, during decomposition due to the activities of decomposers. Furthermore, the same litter type exposed to different decomposer communities exhibited striking differences in chemistry, even after > 90% mass loss. Our results show that during decomposition, decomposer community characteristics regulate changes in litter chemistry, which could influence the functionality of litter-derived soil organic matter (SOM) and the turnover and stabilisation of soil C.
TL;DR: In response to the outbreak of glyphosate-resistant weeds, the seed and agrichemical industries are developing crops that are genetically modified to have combined resistance to glyphosate and synthetic auxin herbicides as discussed by the authors.
Abstract: Agricultural weed management has become entrenched in a single tactic—herbicide—resistant crops—and needs greater emphasis on integrated practices that are sustainable over the long term. In response to the outbreak of glyphosate-resistant weeds, the seed and agrichemical industries are developing crops that are genetically modified to have combined resistance to glyphosate and synthetic auxin herbicides. This technology will allow these herbicides to be used over vastly expanded areas and will likely create three interrelated challenges for sustainable weed management. First, crops with stacked herbicide resistance are likely to increase the severity of resistant weeds. Second, these crops will facilitate a significant increase in herbicide use, with potential negative consequences for environmental quality. Finally, the short-term fix provided by the new traits will encourage continued neglect of public research and extension in integrated weed management. Here, we discuss the risks to sustainable agric...
TL;DR: A conceptual framework that lays out a continuum of bystander opportunities ranging from reactive situations after an assault has occurred, to situations before an Assault has occurred (posing high to low risk to victims), as well as proactive situations where no risk to the victim is present is presented.
Abstract: The bystander intervention approach is gaining popularity as a means for engaging communities in sexual assault prevention, especially on college campuses. Many bystander programs are teaching community members how to intervene without first assisting them to identify the full range of opportunities when they can intervene. In this article, the authors review the literature on sexual violence bystander intervention and present a conceptual framework that lays out a continuum of bystander opportunities ranging from reactive situations after an assault has occurred, to situations before an assault has occurred (posing high to low risk to victims), as well as proactive situations where no risk to the victim is present. The implications of this typology are discussed in the context of program development, evaluation, and further research.
TL;DR: Combined consensus values for this velocity vector are provided and show that they have important implications for the global interstellar interaction, in particular, the velocity is almost certainly slower than the fast magnetosonic speed, with no bow shock forming ahead of the heliosphere, as was widely expected in the past.
Abstract: As the Sun moves through the local interstellar medium, its supersonic, ionized solar wind carves out a cavity called the heliosphere. Recent observations from the Interstellar Boundary Explorer (IBEX) spacecraft show that the relative motion of the Sun with respect to the interstellar medium is slower and in a somewhat different direction than previously thought. Here, we provide combined consensus values for this velocity vector and show that they have important implications for the global interstellar interaction. In particular, the velocity is almost certainly slower than the fast magnetosonic speed, with no bow shock forming ahead of the heliosphere, as was widely expected in the past.
TL;DR: In this paper, the authors used stream network theory combined with data on stream width to estimate the size distribution and areal extent of streams and rivers and found that moderate sized rivers (orders 5-9) seem to comprise the greatest global area, with less area covered by low and high order streams, while global stream length is dominated by 1st order streams.
Abstract: To better integrate lotic ecosystems into global cycles and budgets, we provide approximations of the size-distribution and areal extent of streams and rivers. One approach we used was to employ stream network theory combined with data on stream width. We also used detailed stream networks on 2 continents to estimate the fraction of continental area occupied by streams worldwide and corrected remote sensing stream inventories for unresolved small streams. Our estimates of global fluvial area are 485 000 to 662 000 km2 and are +30–300% of published appraisals. Moderately sized rivers (orders 5–9) seem to comprise the greatest global area, with less area covered by low and high order streams, while global stream length, and therefore the riparian interface, is dominated by 1st order streams. Rivers and streams are likely to cover 0.30–0.56% of the land surface and make contributions to global processes and greenhouse gas emissions that may be +20–200% greater than those implied by previous estimates.
TL;DR: This paper used detrital zircon geochronology, tephro-and magnetostratigraphy, along with analyses of past river flow recorded in sedimentary rocks from the Rukwa Rift Basin, Tanzania, to constrain the timing of rifting, magmatism and drainage development in this part of the western branch.
Abstract: The East African Rift System transects the anomalously high-elevation Ethiopian and East African plateaux that together form part of the 6,000-km-long African superswell structure. Rifting putatively developed as a result of mantle plume activity that initiated under eastern Africa. The mantle activity has caused topographic uplift that has been connected to African Cenozoic climate change and faunal evolution. The rift is traditionally interpreted to be composed of two distinct segments: an older, volcanically active eastern branch and a younger, less volcanic western branch. Here, we show that initiation of rifting in the western branch began more than 14 million years earlier than previously thought, contemporaneously with the eastern branch. We use a combination of detrital zircon geochronology, tephro- and magnetostratigraphy, along with analyses of past river flow recorded in sedimentary rocks from the Rukwa Rift Basin, Tanzania, to constrain the timing of rifting, magmatism and drainage development in this part of the western branch. We find that rift-related volcanism and lake development had begun by about 25 million years ago. These events were preceded by pediment development and a fluvial drainage reversal that we suggest records the onset of topographic uplift caused by the African superswell. We conclude that uplift of eastern Africa was more widespread and synchronous than previously recognized.
TL;DR: Trends provide evidence for some optimism that protective adaptations to the online environment have been successful; however, online harassment appears to be increasing for youth, particularly girls, and may require additional mobilization.
TL;DR: In this article, root-induced changes in soil carbon dynamics in a pine forest exposed to elevated CO2 and N enrichment were measured by combining stable isotope analyses, molecular characterisations of SOM and microbial assays.
Abstract: A common finding in multiple CO2 enrichment experiments in forests is the lack of soil carbon (C) accumulation owing to microbial priming of ‘old’ soil organic matter (SOM). However, soil C losses may also result from the accelerated turnover of ‘young’ microbial tissues that are rich in nitrogen (N) relative to bulk SOM. We measured root-induced changes in soil C dynamics in a pine forest exposed to elevated CO2 and N enrichment by combining stable isotope analyses, molecular characterisations of SOM and microbial assays. We find strong evidence that the accelerated turnover of root-derived C under elevated CO2 is sufficient in magnitude to offset increased belowground inputs. In addition, the C losses were associated with accelerated N cycling, suggesting that trees exposed to elevated CO2 not only enhance N availability by stimulating microbial decomposition of SOM via priming but also increase the rate at which N cycles through microbial pools.
TL;DR: In this paper, the authors discuss some of the key capture technologies and identifies gaps, constraints, and opportunities that facilitate the development and adoption of Low Impact and Fuel Efficient (LIFE) Fishing.
TL;DR: In this paper, the authors used in situ optical sensors for nitrate (NO3ⓘ −) and chromophoric dissolved organic matter fluorescence (FDOM) to measure surface water concentrations at 30min intervals over the snowmelt period (March 21-May 13, 2009) at a 40.5 hectare watershed at Sleepers River, Vermont.
Abstract: Highly resolved time series data are useful to accurately identify the timing, rate, and magnitude of solute transport in streams during hydrologically dynamic periods such as snowmelt. We used in situ optical sensors for nitrate (NO3
−) and chromophoric dissolved organic matter fluorescence (FDOM) to measure surface water concentrations at 30 min intervals over the snowmelt period (March 21–May 13, 2009) at a 40.5 hectare forested watershed at Sleepers River, Vermont. We also collected discrete samples for laboratory absorbance and fluorescence as well as δ18O–NO3
− isotopes to help interpret the drivers of variable NO3
− and FDOM concentrations measured in situ. In situ data revealed seasonal, event and diurnal patterns associated with hydrological and biogeochemical processes regulating stream NO3
− and FDOM concentrations. An observed decrease in NO3
− concentrations after peak snowmelt runoff and muted response to spring rainfall was consistent with the flushing of a limited supply of NO3
− (mainly from nitrification) from source areas in surficial soils. Stream FDOM concentrations were coupled with flow throughout the study period, suggesting a strong hydrologic control on DOM concentrations in the stream. However, higher FDOM concentrations per unit streamflow after snowmelt likely reflected a greater hydraulic connectivity of the stream to leachable DOM sources in upland soils. We also observed diurnal NO3
− variability of 1–2 μmol l−1 after snowpack ablation, presumably due to in-stream uptake prior to leafout. A comparison of NO3
− and dissolved organic carbon yields (DOC, measured by FDOM proxy) calculated from weekly discrete samples and in situ data sub-sampled daily resulted in small to moderate differences over the entire study period (−4 to 1% for NO3
− and −3 to −14% for DOC), but resulted in much larger differences for daily yields (−66 to +27% for NO3
− and −88 to +47% for DOC, respectively). Despite challenges inherent in in situ sensor deployments in harsh seasonal conditions, these data provide important insights into processes controlling NO3
− and FDOM in streams, and will be critical for evaluating the effects of climate change on snowmelt delivery to downstream ecosystems.
University of Connecticut1, University of North Carolina at Chapel Hill2, University of Oklahoma3, University of Georgia4, Richard Stockton College of New Jersey5, West Chester University of Pennsylvania6, University Of Tennessee System7, Western Michigan University8, University of New Hampshire9, East Carolina University10
TL;DR: These guidelines are intended to provide relevant information on preventing sudden death in sports and to give specific recommendations for certified athletic trainers and others participating in athletic health care.
Abstract: Objective: To present recommendations for the prevention and screening, recognition, and treatment of the most common conditions resulting in sudden death in organized sports. Background: Cardiac c...
TL;DR: In this paper, a series of carbon-supported Pd-Sn binary alloyed catalysts were used as anode electrocatalysts for direct ethanol fuel cell reactions in an alkaline medium.
Abstract: In this paper, we present a study of a series of carbon-supported Pd–Sn binary alloyed catalysts prepared through a modified Polyol method as anode electrocatalysts for direct ethanol fuel cell reactions in an alkaline medium. Transmission electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and aberration-corrected scanning transmission electron microscopy equipped with electron energy loss spectroscopy were used to characterize the Pd–Sn/C catalysts, where homogeneous Pd–Sn alloys were determined to be present with the surface Sn being partially oxidized. Among various Pd–Sn catalysts, Pd86Sn14/C catalysts showed much enhanced current densities in cyclic voltammetric and chronoamperometric measurements, compared to commercial Pd/C (Johnson Matthey). The overall rate law of ethanol oxidation reaction for both Pd86Sn14/C and commercial Pd/C were also determined, which clearly showed that Pd86Sn14/C was more favorable in high ethanol concentration ...
Durham University1, Lund University2, Colorado State University3, Institut d'études politiques de Bordeaux4, University of Manchester5, University of Amsterdam6, University of Toronto7, University of Massachusetts Boston8, University of East Anglia9, University of Ottawa10, VU University Amsterdam11, University of New Hampshire12
TL;DR: In this paper, the authors present an analysis of sixty transnational governance initiatives and assess the implications for our understanding of the roles of public and private actors, the legitimacy of governance 'beyond' the state, and the North-South dimensions of governing climate change.
Abstract: With this paper we present an analysis of sixty transnational governance initiatives and assess the implications for our understanding of the roles of public and private actors, the legitimacy of governance 'beyond' the state, and the North-South dimensions of governing climate change. In the first part of the paper we examine the notion of transnational governance and its applicability in the climate change arena, reflecting on the history and emergence of transnational governance initiatives in this issue area and key areas of debate. In the second part of the paper we present the findings from the database and its analysis. Focusing on three core issues, the roles of public and private actors in governing transnationally, the functions that such initiatives perform, and the ways in which accountability for governing global environmental issues might be achieved, we suggest that significant distinctions are emerging in the universe of transnational climate governance which may have considerable implications for the governing of global environmental issues. In conclusion, we reflect on these findings and the subsequent consequences for the governance of climate change.
TL;DR: The main focus of as mentioned in this paper was to obtain plant produced Reclaimed Asphalt Pavement (RAP) mixtures, to document the mixture production parameters and to evaluate the degree of blending between the virgin and RAP binders.
Abstract: The main focus of this study was to obtain plant produced Reclaimed Asphalt Pavement (RAP) mixtures, to document the mixture production parameters and to evaluate the degree of blending between the virgin and RAP binders. The effect of mixture production parameters on the performance (in terms of stiffness, cracking, rutting, and moisture susceptibility) and workability of the mixtures was evaluated. Eighteen plant produced mixtures were obtained from three locations in the Northeast United States. RAP contents (zero to 40%) were varied and softer binders were used. The data and analysis illustrated that the degree of blending between RAP and virgin binders is a function of production parameters. The stiffness of the mixtures increased as the percentage of RAP increased, but not when the discharge temperatures of the mixtures were inconsistent. The cracking resistance was reduced as the percentage of RAP increased. The rutting and moisture damage resistance improved as the percentage of RAP in the mixture...
University of Cambridge1, United States Department of State2, Florida Atlantic University3, Agricultural Research Service4, Florida Fish and Wildlife Conservation Commission5, Northeastern University6, University of New Hampshire7, Virginia Institute of Marine Science8, Silver Spring Networks9, Texas Parks and Wildlife Department10, University of Washington11, University of South Alabama12, The Nature Conservancy13
TL;DR: The first ever large-scale quantitative assessment of the extent and biomass of marine habitat-forming species over a 100-year time frame is presented, finding evidence for a 64 per cent decline in the spatial extent of oyster habitat and an 88% decline in oyster biomass over time.
Abstract: Historic baselines are important in developing our understanding of ecosystems in the face of rapid global change. While a number of studies have sought to determine changes in extent of exploited habitats over historic timescales, few have quantified such changes prior to late twentieth century baselines. Here, we present, to our knowledge, the first ever large-scale quantitative assessment of the extent and biomass of marine habitat-forming species over a 100-year time frame. We examined records of wild native oyster abundance in the United States from a historic, yet already exploited, baseline between 1878 and 1935 (predominantly 1885–1915), and a current baseline between 1968 and 2010 (predominantly 2000–2010). We quantified the extent of oyster grounds in 39 estuaries historically and 51 estuaries from recent times. Data from 24 estuaries allowed comparison of historic to present extent and biomass. We found evidence for a 64 per cent decline in the spatial extent of oyster habitat and an 88 per cent decline in oyster biomass over time. The difference between these two numbers illustrates that current areal extent measures may be masking significant loss of habitat through degradation.
TL;DR: Investigation of the influence of electrostatic surface potential distribution of monoclonal antibodies (MAbs) on intermolecular interactions and viscosity finds replacement of charge residues in the sequence of MAb-2, M-10, did not invoke charge distribution to the same extent as M Ab-1 and hence exhibited a similar viscolysis and self-association profile as Mab-2.
Abstract: The present work investigates the influence of electrostatic surface potential distribution of monoclonal antibodies (MAbs) on intermolecular interactions and viscosity. Electrostatic models suggest MAb-1 has a less uniform surface charge distribution than MAb-2. The patches of positive and negative potential on MAb-1 are predicted to favor intermolecular attraction, even in the presence of a small net positive charge. Consistent with this expectation, MAb-1 exhibits a negative second virial coefficient (B₂₂), an increase in static structure factor, S((q→0)), and a decrease in hydrodynamic interaction parameter, H((q→0)), with increase in MAb-1 concentration. Conversely, MAb-2 did not show such heterogeneous charge distribution as MAb-1 and hence favors intermolecular repulsion (positive B₂₂), lower static structure factor, S((q→0)), and repulsion induced increase in momentum transfer, H((q→0)), to result in lower viscosity of MAb-2. Charge swap mutants of MAb-1, M-5 and M-7, showed a decrease in charge asymmetry and concomitantly a loss in self-associating behavior and lower viscosity than MAb-1. However, replacement of charge residues in the sequence of MAb-2, M-10, did not invoke charge distribution to the same extent as MAb-1 and hence exhibited a similar viscosity and self-association profile as MAb-2.
TL;DR: In this paper, the authors compare near-surface and satellite remote sensing-based observations of vegetation phenology at four deciduous forest sites and show that the specific vegetation index (VI) used to monitor phenology exerts substantial influence on satellite VI derived phenological metrics and by extension, how they compare to VI time series and metrics obtained from near surface remote sensing.
TL;DR: In this paper, a collaborative experimental effort employing the minimally perturbed atmospheric surface-layer flow over the salt playa of western Utah has enabled us to map coherence in turbulent boundary layers at very high Reynolds numbers.
Abstract: A collaborative experimental effort employing the minimally perturbed atmospheric surface-layer flow over the salt playa of western Utah has enabled us to map coherence in turbulent boundary layers at very high Reynolds numbers, \({Re_{\tau}\sim\mathcal{O}(10^6)}\) . It is found that the large-scale coherence noted in the logarithmic region of laboratory-scale boundary layers are also present in the very high Reynolds number atmospheric surface layer (ASL). In the ASL these features tend to scale on outer variables (approaching the kilometre scale in the streamwise direction for the present study). The mean statistics and two-point correlation map show that the surface layer under neutrally buoyant conditions behaves similarly to the canonical boundary layer. Linear stochastic estimation of the three-dimensional correlation map indicates that the low momentum fluid in the streamwise direction is accompanied by counter-rotating roll modes across the span of the flow. Instantaneous flow fields confirm the inferences made from the linear stochastic estimations. It is further shown that vortical structures aligned in the streamwise direction are present in the surface layer, and bear attributes that resemble the hairpin vortex features found in laboratory flows. Ramp-like high shear zones that contribute significantly to the Reynolds shear-stress are also present in the ASL in a form nearly identical to that found in laboratory flows. Overall, the present findings serve to draw useful connections between the vast number of observations made in the laboratory and in the atmosphere.
TL;DR: In this article, a dual stable isotope approach (δ2H and δ18O) was used to trace water inputs, fluxes, and pools through a seasonally dry tropical montane cloud forest in central Veracruz, Mexico.
Abstract: Despite their critical role as freshwater resources and their vulnerability to anthropogenic pressures, our knowledge of the ecohydrology of tropical montane cloud forests remains limited. Here, we use a dual stable isotope approach (δ2H and δ18O) to trace water inputs, fluxes, and pools through a seasonally dry tropical montane cloud forest in central Veracruz, Mexico. We found strong seasonal variation in the isotope composition of precipitation inputs (δ2H ~130‰ and δ18O ~18‰), with significantly more depleted wet-season values as compared with dry-season values. These seasonal differences are subject to inter-annual variation, as reflected by shifts in the local meteoric water line. Even at the peak of the dry season, stable isotope values of plant xylem water from six different deciduous and evergreen species occurring in the understory and canopy of mature and secondary forests were all consistent with the use of shallow soil water (20–60 cm). Alternative limiting factors, such as nutrient distribution along the soil profile, may be strongly contributing to plant rooting patterns. Stable isotope values of soil water were evaporatively enriched compared with precipitation inputs, whereas stream values plotted with precipitation on the local meteoric water line. In contrast to current hydrologic models, this indicates the presence of two distinct soil water pools, one highly mobile pool of precipitation that contributes to streams and a second less mobile pool of soil water that contributes to plant fluxes. This comprehensive perspective can provide the basis for generating process-based models of ecohydrology in the future. Copyright © 2011 John Wiley & Sons, Ltd.