bluuebunny/crossref_metadata_2025 huggingface dataset:
In Vitro and In Vivo Analysis of the Gram-Negative Bacteria–Derived Riboflavin Precursor Derivatives Activating Mouse MAIT Cells
Authors: Soudais Claire , Samassa Fatoumata , Sarkis Manal , Le Bourhis Lionel , Bessoles Stéphanie , Blanot Didier , Hervé Mireille , Schmidt Frédéric , Mengin-Lecreulx Dominique , Lantz Olivier
Published: April 2015

Mucosal-associated invariant T (MAIT) cells recognize microbial compounds presented by the MHC-related 1 (MR1) protein. Although riboflavin precursor derivatives from Gram-positive bacteria have been characterized, some level of ligand heterogeneity has been suggested through the analysis of the MAIT cell TCR repertoire in humans and differential reactivity of human MAIT cell clones according to the bacteria. In this study, using Gram-negative bacteria mutated for the riboflavin biosynthetic pathway, we show a strict correlation between the ability to synthesize the 5-amino-ribityl-uracil riboflavin precursor and to activate polyclonal and quasi-monoclonal mouse MAIT cells. To our knowledge, we show for the first time that the semipurified bacterial fraction and the synthetic ligand activate murine MAIT cells in vitro and in vivo. We describe new MR1 ligands that do not activate MAIT cells but compete with bacterial and synthetic compounds activating MAIT cells, providing the capacity to modulate MAIT cell activation. Through competition experiments, we show that the most active synthetic MAIT cell ligand displays the same functional avidity for MR1 as does the microbial compound. Altogether, these results show that most, if not all, MAIT cell ligands found in Escherichia coli are related to the riboflavin biosynthetic pathway and display very limited heterogeneity.
IL-33 Reverses an Obesity-Induced Deficit in Visceral Adipose Tissue ST2+ T Regulatory Cells and Ameliorates Adipose Tissue Inflammation and Insulin Resistance
Authors: Han Jonathan M. , Wu Dan , Denroche Heather C. , Yao Yu , Verchere C. Bruce , Levings Megan K.
Published: April 2015

Obesity is associated with insulin resistance and inflammation thought to be caused by a visceral adipose tissue (VAT)–localized reduction in immunoregulatory cells and increase in proinflammatory immune cells. We previously found that VAT regulatory T cells (Tregs) normally express high levels of IL-10 and that expression of this cytokine in VAT Tregs is specifically reduced in mice fed a high-fat diet. In this study, we further investigated the phenotype of VAT Tregs and found that the majority of IL-10–expressing Tregs in the VAT of lean mice also expressed the ST2 chain of the IL-33R. In addition to high expression of IL-10, ST2+ Tregs in lean VAT expressed higher proportions of Th2-associated proteins, including GATA3 and CCR4, and Neuropillin-1 compared with ST2− Tregs. The proportion of ST2+ Tregs in VAT was severely diminished in obese mice that had been fed a high-fat/sucrose diet, and this effect could be completely reversed by treatment with IL-33. IL-33 treatment also reversed VAT inflammation in obese mice and resulted in a reduction of hyperinsulinemia and insulin resistance. These data suggest that IL-33 contributes to the maintenance of the normal pool of ST2+ Tregs in the VAT, and that therapeutic administration of IL-33 results in multiple anti-obesity effects, including the reversal of VAT inflammation and alleviation of insulin resistance.
Information to Act: Household Characteristics are Predictors of Domestic Infestation with the Chagas Vector Triatoma dimidiata in Central America
Authors: Bustamante Zamora Dulce María , Hernández Marianela Menes , Torres Nuria , Zúniga Concepción , Sosa Wilfredo , de Abrego Vianney , Monroy Escobar María Carlota
Published: April 2015

The interruption of vectorial transmission of Chagas disease by Triatoma dimidiata in central America is a public health challenge that cannot be resolved by insecticide application alone. In this study, we collected information on previously known household risk factors for infestation in 11 villages and more than 2,000 houses in Guatemala, Honduras, and El Salvador, and we constructed multivariate models and used multimodel inference to evaluate their importance as predictors of infestation in the region. The models had moderate ability to predict infested houses (sensitivity, 0.32–0.54) and excellent ability to predict noninfested houses (specificity higher than 0.90). Predictive ability was improved by including random village effects and presence of signs of infestation (insect feces, eggs, and exuviae) as fixed effects. Multimodel inference results varied depending on factors included, but house wall materials (adobe, bajareque, and palopique) and signs of infestation were among the most important predictive factors. Reduced models were not supported suggesting that all factors contributed to predictions. Previous knowledge and information from this study show that we have evidence to prioritize rural households for improvement to prevent house infestation with Triatoma dimidiata in Central America. House improvement will most likely have other health co-benefits.
Evaluation of Point-of-Contact Circulating Cathodic Antigen Assays for the Detection of Schistosoma mansoni Infection in Low-, Moderate-, and High-Prevalence Schools in Western Kenya
Authors: Foo Karen T. , Blackstock Anna J. , Ochola Elizabeth A. , Matete Daniel O. , Mwinzi Pauline N. M. , Montgomery Susan P. , Karanja Diana M. S. , Secor W. Evan
Published: April 2015

We evaluated the performance of a point-of-contact circulating cathodic antigen assay (POC-CCA) to detect schistosome infections in primary school children (N = 1,801) living in areas with low, moderate, and high Schistosoma mansoni prevalence in western Kenya. The commercially available assay (CCA-1) and a second, experimental formulation (CCA-2) were compared against Kato-Katz stool examinations and an anti-schistosome enzyme-linked immunosorbent assay (ELISA). A latent class model based on the four tests was used to establish “true infection status” in three different zones based on their distance from Lake Victoria. As a screening tool for community treatment according to World Health Organization (WHO) guidelines, the Kato-Katz examination was in closest agreement with the latent class model, followed by the experimental CCA-2, soluble adult worm antigen preparation (SWAP) ELISA, and CCA-1, which had high sensitivity compared with the other tests but was consistently the least specific. Our experience suggests that POC-CCA tests offer a field-friendly alternative to Kato-Katz, but need further interpretation for appropriate field use.
Exploring the Contribution of Host Susceptibility to Epidemiological Patterns of Schistosoma japonicum Infection Using an Individual-Based Model
Authors: Wang Shuo , Spear Robert C.
Published: April 2015

We recently reported the analysis of epidemiological data suggesting variability in individual susceptibility to infection by Schistosoma japonicum among rural villagers who reside in Sichuan Province of southwestern China. By supplementing the data used in the earlier analysis from other studies we have reported from this region, we presented improved estimates of cercarial exposure, which in turn, result in stronger evidence of susceptibility. This analysis was conducted using an individual-based mathematical model (IBM) whose use was motivated by the nature and extent of field data from the low-transmission environments exemplified by one of our datasets and typical of the current situation in most endemic areas of China. In addition to individual susceptibility and water contact, the model includes stochastic aspects of cercarial exposure as well as of diagnostic procedures, the latter being particularly relevant to the low-transmission environment. The simulation studies show that, to produce key aspects of the epidemiological findings, the distribution of susceptibility ranges over several orders of magnitude and is highly right skewed. We found no compelling evidence that the distribution of susceptibility differed between the two populations that underlie both the epidemiological and simulation results.
Evidence of Limited Polyandry in a Natural Population of Aedes aegypti
Authors: Richardson Joshua B. , Jameson Samuel B. , Gloria-Soria Andrea , Wesson Dawn M. , Powell Jeffrey
Published: April 2015

The mosquito Aedes aegypti is a vector of yellow fever, dengue, and chikungunya. Control of the insect is crucial to stop the spread of dengue and chikungunya, so it is critically important to understand its mating behavior. Primarily, based on laboratory behavior, it has long been assumed that Ae. aegypti females mate once in their lifetime. However, multiple inseminations have been observed in semi-field and laboratory settings, and in closely related species. Here, we report the first evidence of polyandry in a natural population of Ae. aegypti. Female Ae. aegypti were captured around the New Orleans, LA, metropolitan area. They were offered a blood meal and allowed to lay eggs, which were reared to the third-instar larval stage. A parentage analysis using four microsatellite loci was performed. Out of 48 families, 3 showed evidence of multiple paternity. An expanded analysis of these three families found that one family group included offspring contributed by three fathers, and the other two included offspring from two fathers. This result establishes that polyandry can occur in a small proportion of Ae. aegypti females in a natural setting. This could complicate future genetic control efforts and has implications for sampling for population genetics.
Quantitation of Blomia tropicalis Allergen Blo t 5 in Cereal and Cereal-Based Foods Consumed in the Nile Delta, Egypt
Authors: Hussein Atef H. , Elawamy Waleed
Published: April 2015

The mite Blomia tropicalis has significant prevalence worldwide. Blo t 5 is a major B. tropicalis allergen that has been associated with sensitization and allergic symptoms in many asthmatic patients. Besides house dust, contaminated foodstuffs are an important source of exposure to B. tropicalis allergens. In this study, a double sandwich enzyme-linked immunosorbent assay (ELISA) using mAb 4D4 and biotinylated mAb 4G9 was done to detect Blo t 5 allergen in different types of raw and processed foods, including wheat, corn, rice, bean, wheat and corn flour, cake, and rusk, which were collected from retail stores in the Nile Delta of Egypt. Out of 88 samples, 38 (43.2%) were positive for Blo t 5 allergen with no significant statistical difference in positivity according to food type. In positive samples, the Blo t 5 concentration ranged from 10 ng/g to 790 ng/g. This study showed that Blo t 5 should be considered as an important allergen that presents a risk to the Egyptian population and should become a routine allergen in the skin prick test to improve the management of allergic disease.
Human Granulocytic Anaplasmosis in the United States from 2008 to 2012: A Summary of National Surveillance Data
Authors: Dahlgren F. Scott , Heitman Kristen Nichols , Drexler Naomi A. , Massung Robert F. , Behravesh Casey Barton
Published: April 2015

Human granulocytic anaplasmosis is an acute, febrile illness transmitted by the ticks Ixodes scapularis and Ixodes pacificus in the United States. We present a summary of passive surveillance data for cases of anaplasmosis with onset during 2008–2012. The overall reported incidence rate (IR) was 6.3 cases per million person-years. Cases were reported from 38 states and from New York City, with the highest incidence in Minnesota (IR = 97), Wisconsin (IR = 79), and Rhode Island (IR = 51). Thirty-seven percent of cases were classified as confirmed, almost exclusively by polymerase chain reaction. The reported case fatality rate was 0.3% and the reported hospitalization rate was 31%. IRs, hospitalization rates, life-threatening complications, and case fatality rates increased with age group. The IR increased from 2008 to 2012 and the geographic range of reported cases of anaplasmosis appears to have increased since 2000–2007. Our findings are consistent with previous case series and recent reports of the expanding range of the tick vector I. scapularis.
Clinton’s Grand Strategy
Authors: Boys James D.
Published: April 2015

President Clinton’s time in office coincided with historic global events following the end of the Cold War. The collapse of Communism called for a new US Grand Strategy to address the emerging geopolitical era that brought upheavals in Somalia and the Balkans, economic challenges in Mexico and Europe and the emergence of new entities such as the EU, NAFTA and the WTO. Clinton's handling of these events was crucial to the development of world politics at the dawn of the twenty-first century. Only by understanding Clinton’s efforts to address the challenges of the post-Cold War era can we understand the strategies of his immediate successors, George W. Bush and Barack Obama, both of whom inherited and continued Clinton-era policies and practices.

James D. Boys sheds new light on the evolution and execution of US Grand Strategy from 1993 to 2001. He explores the manner in which policy was devised and examines the actors responsible for its development, including Bill Clinton, Anthony Lake, Samuel Berger, Warren Christopher, Madeline Albright and Richard Holbrook. He examines the core components of the strategy (National Security, Prosperity Promotion and Democracy Promotion) and how they were implemented, revealing a hitherto unexplored continuity from campaign trail to the White House.

Covering the entire duration of Clinton’s presidential odyssey, from his 1991 Announcement Speech to his final day in office, the book draws extensively on newly declassified primary materials and interviews by the author with key members of the Clinton administration to reveal for the first time the development and implementation of US Grand Strategy from deep within the West Wing of the Clinton White House.
Food and Identity in England, 1540–1640
Authors: Lloyd Paul S.
Published: April 2015

Food and Identity in England, 1540-1640 considers early modern food consumption in an important new way, connecting English consumption practices between the reigns of Henry VIII and Charles I with ideas of ‘self’ and ‘otherness’ in wider contexts of society and the class system.

Examining the diets of various social groups, ranging from manual labourers to the aristocracy, special foods and their preparation, as well as festive events and gift foods, this all-encompassing study reveals the extent to which individuals and communities identified themselves and others by what and how they ate between the Reformation of the church and the English Civil Wars. This text provides remarkable insights for anyone interested in knowing more about the society and culture of early modern England.
The Black Pacific
Authors: Shilliam Robbie
Published: April 2015

Why have the struggles of the African Diaspora so resonated with South Pacific people? How have Maori, Pasifika and Pakeha activists incorporated the ideologies of the African diaspora into their struggle against colonial rule and racism, and their pursuit of social justice?

This book challenges predominant understandings of the historical linkages that make up the (post-)colonial world. The author goes beyond both the domination of the Atlantic viewpoint, and the correctives now being offered by South Pacific and Indian Ocean studies, to look at how the Atlantic ecumene is refracted in and has influenced the Pacific ecumene. The book is empirically rich, using extensive interviews, participation and archival work and focusing on the politics of Black Power and the Rastafari faith. It is also theoretically sophisticated, offering an innovative hermeneutical critique of post-colonial and subaltern studies.

The Black Pacific is essential reading for students and scholars of Politics, International Relations, History and Anthropology interested in anti-colonial struggles, anti-racism and the quests for equality, justice, freedom and self-determination.
Christian Metal
Authors: Moberg Marcus
Published: April 2015

Christian metal has always defined itself in contrast to its non-Christian, secular counterpart, yet it stands out from nearly all other forms of contemporary Christian music through its unreserved use of metal’s main musical, visual, and aesthetic traits. Christian metal is a rare example of a direct combination between evangelical Christianity and an aggressive and highly controversial form of popular music and its culture.

Christian Metal: History, Ideology, Scene is the first full exploration of the phenomenon of Christian metal music, its history, main characteristics, development, diversification, and key ideological traits from its formative years in the early 1980s to the present day. Marcus Moberg situates it in a wider international evangelical cultural environment, accounts for its diffusion on a transnational scale, and explores what religious meanings and functions Christian metal holds for its own musicians and followers. Engaging with wider debates on religion, media and popular culture, Christian Metal: History, Ideology and Scene is a much-needed resource in the study of religion and popular music.
Cinema of Simulation
Authors: Laist Randy
Published: April 2015

Hyperreality is an Alice-in-Wonderland dimension where copies have no originals, simulation is more real than reality, and living dreams undermine the barriers between imagination and objective experience. The most prominent philosopher of the hyperreal, Jean Baudrillard, formulated his concept of hyperreality throughout the 1980s, but it was not until the 1990s that the end of the Cold War, along with the proliferation of new reality-bending technologies, made hyperreality seem to come true. In the “lost decade” between the fall of the Berlin Wall and 9/11, the nature of reality itself became a source of uncertainty, a psychic condition that has been recognizably recorded by that seismograph of American consciousness, Hollywood cinema.

The auteur cinema of the 1970s aimed for gritty realism, and the most prominent feature of Reagan-era cinema was its fantastic unrealism. Clinton-era cinema, however, is characterized by a prevailing mood of hyperrealism, communicated in various ways by such benchmark films as JFK, Pulp Fiction, and The Matrix. The hyperreal cinema of the 1990s conceives of the movie screen as neither a window on a preexisting social reality (realism), nor as a wormhole into a fantastic dream-dimension (escapism), but as an arena in which images and reality exchange masks, blend into one another, and challenge the philosophical premises which differentiate them from one another. Cinema of Simulation: Hyperreal Hollywood in the Long 1990s provides a guided tour through the anxieties and fantasies, reciprocally social and cinematic, which characterize the surreal territory of the hyperreal.
Breach of Contact: An Intercultural Reading of China Miéville's 'The City and The City'
Authors: Hanna Barbara Elizabeth , Cowley Peter
Published: April 2015

China Miéville’s 2009 'Weird' detective novel The City and The City is a tale of two city states, culturally distinct, between which unpoliced contact is forbidden. While residents of each city can learn about the other’s history, geography, politics, see photographs and watch news footage of the other city, relations between the two are tightly monitored and any direct contact requires a series of protocols, some of which might seem reasonable, or at least familiar: entry permits, international mail, international dialing codes, intercultural training courses. What complicates these apparently banal measures is the relative positioning of the two cities, each one around, within, amongst the other. The two populations live side by side, under a regime which requires ostentatious and systematic disregard or 'unnoticing' of the other in any context but a tightly regulated set of encounters. For all that interculturality is endemic to everyday life in the 21st century, what is striking is that critical and popular uptake of this novel so frequently decries the undesirability, the immorality even, of the cultural separation between the two populations, framing it as an allegory of unjust division within a single culture, and thus by implication endorsing the erasure of intercultural difference. We propose an alternative reading which sees this novel as exploring the management of intercultural encounters, and staging the irreducibility of intercultural difference. We examine how the intercultural is established in the novel, and ask how it compares to its representations in prevalent theoretical models, specifically that of the Third Place.
Improvements in AOD retrieval from geostationary measurements over Asia with aerosol optical properties derived from the DRAGON-Asia campaign
Authors: Kim M. , Kim J. , Jeong U. , Kim W. , Holben B. , Eck T. F. , Lim J. H. , Song C. K. , Lee S.
Published: April 2015

Abstract. An aerosol model optimized for East Asia is improved by applying inversion data from both long-term monitoring of the Aerosol Robotic Network (AERONET) sun photometer and the Distributed Regional Aerosol Gridded Observation Networks (DRAGON)-Asia campaign from 2012. This model plays an important role in retrieving accurate aerosol optical depth (AOD) from satellite-based measurements. In particular, the performance of a single visible channel algorithm, limited to a specific aerosol type, from real-time measurements is strongly affected by the assumed aerosol optical properties (AOPs) for the measured scene. In sensitivity tests, a 4% difference in single scattering albedo (SSA) between modeled and measured values can cause a retrieval error in AOD of over 20%, and the overestimation of SSA leads to an underestimation of AOD. Based on the AERONET inversion datasets obtained over East Asia before 2011, seasonally analyzed AOPs can be summarized by SSAs (measured at 675 nm) of 0.92, 0.94, 0.92, and 0.91 for spring (March, April, and May), summer (June, July, and August), autumn (September, October, and November), and winter (December, January, and February), respectively. After DRAGON-Asia 2012, the SSA during spring shows a slight increase to 0.93. The large volume of data and spatially concentrated measurements from this campaign can be used to improve the representative aerosol model for East Asia. Accordingly, the AOD datasets retrieved from a single channel algorithm, which uses a pre-calculated look-up table (LUT) with the new aerosol model, show an improved correlation with the measured AOD during the DRAGON-Asia campaign (March to May 2012). Compared with the correlation of the AOD retrieved using the original aerosol model, the regression slope between the new AOD and the AERONET values is reduced from 1.08 to 1.00, while the change of the y-offset of −0.08 is significant. The correlation coefficients for the comparisons are 0.87 and 0.85, respectively. The tendency of the original aerosol model to overestimate the retrieved AOD is significantly improved by using the SSA values obtained using the new model.
Trace metal characterization of aerosol particles and cloud water during HCCT 2010
Authors: Fomba K. W. , van Pinxteren D. , Müller K. , Iinuma Y. , Lee T. , Collet Jr. J. , Herrmann H.
Published: April 2015

Abstract. Trace metal characterization of bulk and size resolved aerosol and cloud water samples were performed during the Hill Cap Cloud Thuringia (HCCT) campaign. Cloud water was collected at the top of Mt. Schmücke while aerosol samples were collected at two stations upwind and downwind of Mt. Schmücke. Fourteen trace metals including Ti, V, Fe, Mn, Co, Zn, Ni, Cu, As, Sr, Rb, Pb, Cr, and Se were investigated during four full cloud events (FCE) that fulfilled the conditions of a continuous air mass flow through the three stations. Aerosol particle trace metal concentrations were found to be lower than those observed in the same region during previous field experiments but were within a similar range to those observed in other rural regions in Europe. Fe and Zn were the most abundant elements with concentration ranges of 0.2–111.6 and 1.1–32.1 ng m−3, respectively. Fe, Mn and Ti were mainly found in coarse mode aerosols while Zn, Pb and As were mostly found in the fine mode. Correlation and enrichment factor analysis of trace metals revealed that trace metals such as Ti and Rb were mostly of crustal origin while trace metals such as Zn, Pb, As, Cr, Ni, V, and Cu were of anthropogenic origin. Trace metals such as Fe, Mn, were of mixed origins including crustal and combustion sources. Trace metal cloud water concentration decreased from Ti, Mn, Cr, to Co with average concentrations of 9.18, 5.59, 5.54, and 0.46 μg L−1, respectively. A non-uniform distribution of soluble Fe, Cu and Mn was observed across the cloud drop sizes. Soluble Fe and Cu were found mainly in cloud droplets with diameters between 16 and 22 μm while Mn was found mostly in larger drops greater than 22 μm. Fe (III) was the main form of soluble Fe especially in the small and larger drops with concentrations ranging from 2.2 to 37.1 μg L−1. In contrast to other studies, Fe (II) was observed mainly in the evening hours, implying its presence was not directly related to photochemical processes. Aerosol cloud interaction did not lead to a mark increase in soluble trace metal concentrations, but led to differences in the chemical composition of the aerosol due to preferential loss of aerosol particles through physical processes including cloud drop deposition to vegetative surfaces.
A simple optical index shows spatial and temporal heterogeneity in phytoplankton community composition during the 2008 North Atlantic Bloom Experiment
Authors: Cetinić I. , Perry M. J. , D'Asaro E. , Briggs N. , Poulton N. , Sieracki M. E. , Lee C. M.
Published: April 2015

Abstract. The ratio of two in situ optical measurements – chlorophyll fluorescence (Chl F) and optical particulate backscattering (bbp) – varied with changes in phytoplankton community composition during the North Atlantic Bloom Experiment in the Iceland Basin in 2008. Using ship-based measurements of Chl F, bbp, chlorophyll a (Chl), high-performance liquid chromatography (HPLC) pigments, phytoplankton composition and carbon biomass, we found that oscillations in the ratio varied with changes in plankton community composition; hence we refer to Chl F/bbp as an "optical community index". The index varied by more than a factor of 2, with low values associated with pico- and nanophytoplankton and high values associated with diatom-dominated phytoplankton communities. Observed changes in the optical index were driven by taxa-specific chlorophyll-to-autotrophic carbon ratios and by physiological changes in Chl F associated with the silica limitation. A Lagrangian mixed-layer float and four Seagliders, operating continuously for 2 months, made similar measurements of the optical community index and followed the evolution and later demise of the diatom spring bloom. Temporal changes in optical community index and, by implication, the transition in community composition from diatom to post-diatom bloom communities were not simultaneous over the spatial domain surveyed by the ship, float and gliders. The ratio of simple optical properties measured from autonomous platforms, when carefully validated, provides a unique tool for studying phytoplankton patchiness on extended temporal scales and ecologically relevant spatial scales and should offer new insights into the processes regulating patchiness.
Halocarbon emissions and sources in the equatorial Atlantic Cold Tongue
Authors: Hepach H. , Quack B. , Raimund S. , Fischer T. , Atlas E. L. , Bracher A.
Published: April 2015

Abstract. Halocarbons from oceanic sources contribute to halogens in the troposphere, and can be transported into the stratosphere where they take part in ozone depletion. This paper presents distribution and sources in the equatorial Atlantic from June and July 2011 of the four compounds bromoform (CHBr3), dibromomethane (CH2Br2), methyl iodide (CH3I) and diiodomethane (CH2I2). Enhanced biological production during the Atlantic Cold Tongue (ACT) season, indicated by phytoplankton pigment concentrations, led to elevated concentrations of CHBr3 of up to 44.7 pmol L−1 and up to 9.2 pmol L−1 for CH2Br2 in surface water, which is comparable to other tropical upwelling systems. While both compounds correlated very well with each other in the surface water,CH2Br2 was often more elevated in greater depth than CHBr3, which showed maxima in the vicinity of the deep chlorophyll maximum. The deeper maximum of CH2Br2 indicates an additional source in comparison to CHBr3 or a slower degradation of CH2Br2. Concentrations of CH3I of up to 12.8 pmol L−1 in the surface water were measured. In contrary to expectations of a predominantly photochemical source in the tropical ocean, its distribution was mostly in agreement with biological parameters, indicating a~biological source. CH2I2 was very low in the near surface water with maximum concentrations of only 3.7 pmol L−1, and the observed anticorrelation with global radiation was likely due to its strong photolysis. CH2I2 showed distinct maxima in deeper waters similar to CH2Br2. For the first time, diapycnal fluxes of the four halocarbons from the upper thermocline into and out of the mixed layer were determined. These fluxes were low in comparison to the halocarbon sea-to-air fluxes. This indicates that despite the observed maximum concentrations at depth, production in the surface mixed layer is the main oceanic source for all four compounds and has an influence on emissions into the atmosphere. The calculated production rates of the compounds yield 34 (CHBr3), 10 (CH2Br2), 21 (CH3I) and 384 (CH2I2) pmol m−3 h−1 in the whole mixed layer.
Effects of flooding on organic carbon consumption in the East China Sea
Authors: Chen C.-C. , Gong G.-C. , Chou W.-C. , Chung C.-C. , Shiah F.-K. , Chiang K.-P.
Published: April 2015

Abstract. This study was designed to determine the effects of flooding on plankton community respiration (CR) in the East China Sea (ECS). In July 2010, a devastating flood occurred in the Changjiang River; the mean monthly discharge was 60 527 m3 s−1. To compare, the variables were also examined in the low riverine flow of July 2009 (33 955 m3 s−1). During the flooding, the Changjiang diluted water (CDW) zone, the sea surface salinity (SSS) was ≤ 31 psu, covering almost two thirds of the ECS, which was approximately six times that in the non-flooding period. The mean nitrate concentration was higher in 2010 (6.2 μM) than in 2009 (2.0 μM). However, in the 2010 flood, the mean values of Chl a and the bacterial biomass were only slightly higher or even lower than in 2009. Surprisingly, however, the CR was still higher in the flood period than in the non-flood period, with mean values of 105.6 and 73.2 mg C m−3 d−1, respectively. The higher CR in 2010 could be attributed to vigorous plankton activities, especially phytoplankton, at stations in the CDW zone, which were not mostly covered by low SSS in 2009. There was a huge amount of fCO2 drawdown in the 2010 flood. These results suggested that the devastating flood in 2010 had a significant effect on the carbon balance in the ECS. This effect might become more pronounced as extreme rainfall events and flooding magnitudes increase dramatically throughout the world.
Linking dissolved organic matter composition to metal bioavailability in agricultural soils: effect of anionic surfactants
Authors: Hernandez-Soriano M. C. , Jimenez-Lopez J. C.
Published: April 2015

Abstract. The bioavailability of metals in soil is only partially explained by their partition among the solid and aqueous phase and is more related to the characterization of their speciation in the soil solution. The organic ligands in solution that largely determine metal speciation involve complex mixtures and the characterization of fluorescence components of dissolved organic matter (DOM) can identify pools of molecules that participate in metal speciation, this being essential for risk assessment. The bioavailability of Cd, Cu, Pb and Zn in three agricultural soils was examined in the laboratory to recreate irrigation with greywater enriched in anionic surfactants (Aerosol 22 and Biopower). Field capacity and saturation regimes were considered for this study. Irrigation with aqueous solutions of the anionic surfactants increased total DOM concentrations and metals in the soil solution (Pb > Cu > Zn > Cd). Significant correlation (p < 0.05) between the readily available pool of metals with the concentration of DOM was determined for Cu (r = 0.67), Pb (r = 0.82) and Zn (r = 0.68). However, speciation analysis performed with the software WHAM indicated that mobilisation of DOM and metals into the soluble phase resulted in a low concentration of free ion activities and promoted the formation of metal-organo complexes. The characterization of fluorescence components revealed that DOM in soil solution from soils irrigated with Aerosol 22 was enriched in a reduced quinone-like and a humic-like component. Besides, fluorescence quenching provided further evidence of metal complexation with organic ligands in solution. Hence, metal mobilization in soil irrigated with surfactant enriched greywater occurs with solubilisation of high affinity organic ligands, which substantially decreases the potential risk of metal toxicity.
Variability in terrigenous sediment supply offshore of the Rio de la Plata (Uruguay) recording the continental climatic history over the past 1200 years
Authors: Perez L. , García-Rodríguez F. , Hanebuth T. J. J.
Published: April 2015

Abstract. The continental shelf adjacent to the Río de la Plata (RdlP) exhibits extremely complex hydrographic and ecological characteristics which are of great socio-economic importance. Since the long-term environmental variations related to the atmospheric (wind fields), hydrologic (freshwater plume), and oceanographic (currents and fronts) regimes are little known, the aim of this study is to reconstruct the changes in the terrigenous input into the inner continental shelf during the Late Holocene period (associated with the RdlP sediment discharge) and to unravel the climatic forcing mechanisms behind them. To achieve this, we retrieved a 10 m long sediment core from the RdlP mud depocenter at a depth of 57 m (GeoB 13813-4). The radiocarbon age control indicated an extremely high sedimentation rate of 0.8 cm per year, encompassing the past 1200 years (750–2000 AD). We used element ratios (Ti / Ca, Fe / Ca, Ti / Al, Fe / K) as regional proxies for the fluvial input signal, and the variations in relative abundance of salinity-indicative diatom groups (freshwater vs. marine-brackish) to assess the variability in terrigenous water and sediment discharge. Ti / Ca, Fe / Ca, Ti / Al, Fe / K and the freshwater diatom group showed the lowest values between 850 and 1300 AD, while the highest values occurred between 1300 and 1850 AD. The variations in the sedimentary record can be attributed to such regional and global climatic episodes as the Medieval Climatic Anomaly (MCA) and the Little Ice Age (LIA), both of which had a significant impact on rainfall and wind patterns over the region. During the MCA, a northward migration of the Intertropical Confluence Zone (ITCZ) could explain the lowest element ratios (indicative of a lower terrigenous input) and a marine-dominated diatom record, both indicative of a reduced RdlP freshwater plume. In contrast during the LIA, the southward migration of the ITCZ accompanied by El Niño-like state conditions may have led to an expansion of RdlP river plume far to the north, as indicated by higher element ratios and a marked freshwater diatom signal. During the current warm period (i.e., after 1900 AD), the highest values in the element ratios and a pronounced marine to marine-brackish diatom record was found. This discordance between diatom record and sediment supply during the last century could be the consequence of an anthropogenic impact on the drainage basin and the RdlP system, expressed by the artificial increase in metal concentrations in the offshore sediments.
Using field observations to inform thermal hydrology models of permafrost dynamics with ATS (v0.83)
Authors: Atchley A. L. , Painter S. L. , Harp D. R. , Coon E. T. , Wilson C. J. , Liljedahl A. K. , Romanovsky V. E.
Published: April 2015

Abstract. Climate change is profoundly transforming the carbon-rich Arctic tundra landscape, potentially moving it from a carbon sink to a carbon source by increasing the thickness of soil that thaws on a seasonal basis. However, the modeling capability and precise parameterizations of the physical characteristics needed to estimate projected active layer thickness (ALT) are limited in Earth System Models (ESMs). In particular, discrepancies in spatial scale between field measurements and Earth System Models challenge validation and parameterization of hydrothermal models. A recently developed surface/subsurface model for permafrost thermal hydrology, the Advanced Terrestrial Simulator (ATS), is used in combination with field measurements to calibrate and identify fine scale controls of ALT in ice wedge polygon tundra in Barrow, Alaska. An iterative model refinement procedure that cycles between borehole temperature and snow cover measurements and simulations functions to evaluate and parameterize different model processes necessary to simulate freeze/thaw processes and ALT formation. After model refinement and calibration, reasonable matches between simulated and measured soil temperatures are obtained, with the largest errors occurring during early summer above ice wedges (e.g. troughs). The results suggest that properly constructed and calibrated one-dimensional thermal hydrology models have the potential to provide reasonable representation of the subsurface thermal response and can be used to infer model input parameters and process representations. The models for soil thermal conductivity and snow distribution were found to be the most sensitive process representations. However, information on lateral flow and snowpack evolution might be needed to constrain model representations of surface hydrology and snow depth.
Micro-structured electron accelerator for the mobile gas ionization sensor technology
Authors: Zimmer C. M. , Kallis K. T. , Giebel F. J.
Published: April 2015

Abstract. Mobile and economically priced gas monitoring and warning systems will become increasingly important for civil security, such as in fire brigade operations in undefined hazardous environments (Daum et al., 2006). Normally, photoionization detectors (PIDs) are used for the detection of gases. Hereby, the principle is based upon the ionization of the measured gas by photons, which are generated by a high-energetic gas discharge lamp with energy of 10–11 eV. Besides the detrimental unspecific gas detection because of the ionization of all gases with ionization potential (IP) below the provided photon energy, sensors also have a short lifetime combined with a high cost (http://www.intlsensor.com/pdf/photoionization.pdf). This can be remedied by the concept of an electronic supported photoionization detector (ePID; Zimmer et al., 2012) consisting of a durable UV-LED with an above-positioned electron accelerator chip manufactured on a glass substrate by planar technology. Photoelectrons are extracted by UV illumination out of the bottom electrode and will be accelerated to an energy matching the ionization potential of the gas by a downstream acceleration grid. Thereby, the stable honeycomb-structured grid acts as a porous separator between the evacuated electron acceleration path due to nm scaling and the ionization area of the detector. To enhance the emitting area yielding a higher photoelectron current, the grid structure almost levitates, realized by the use of compatible planar technological processes such as reactive ion etching (RIE) and isotropic wet etching of sacrificial layers, which will be explained in detail in this paper. Furthermore, the tunability of the grid's acceleration voltage would enable a substance-specific determination of the gas composition, where the ionization of the analytes is clearly performed by photoelectrons instead of photons.
Responding to the challenges of water security: the Eighth Phase of the International Hydrological Programme, 2014–2021
Authors: Jimenez-Cisneros B.
Published: April 2015

Abstract. This paper presents the major water challenges at global, regional and local levels, including the need to adapt to climate change. It relates how the International Hydrological Programme (IHP) – an intergovernmental scientific programme – will respond in its Eighth Phase to the water-related risks and seize potential opportunities, thereby contributing to ensure Water Security at all levels. The Member States of UNESCO IHP periodically define priorities for research, technological development, innovation and education. To implement the priorities in a coordinated manner, the Member States can count on the team and the projects of IHP based at UNESCO, as well as on the "UNESCO Water Family|, consisting to date of a Category 1 centre UNESCO-IHE located in the Netherlands; the World Water Assessment Programme, based in Italy, which produces the World Water Development Report of the United Nations; 30 Category 2 water centres under the auspices of UNESCO; and 35 water chairs in various parts of the world. Governments can access the powerful network of the UNESCO Water Family through IHP and its Intergovernmental Council.
New problems and opportunities of oil spill monitoring systems
Authors: Barenboim G. M. , Borisov V. M. , Golosov V. N. , Saveca A. Yu.
Published: April 2015

Abstract. Emergency oil and oil products spills represent a great danger to the environment, including ecosystems, and to the population. New problems of such dangerous spills and methods of early detection are discussed in this paper. It is proposed to conduct assessment of biological hazards of such spills on the basis of data on the distribution of individual oil hydrocarbons within the column of the water body and computer predictions of their toxicity. Oil radioactivity, which is associated with uranium and thorium, is seen as the important aspect of the oil spill danger, especially in watercourses. The need for an automated monitoring system for the early detection of oil spills in water bodies is analysed. The proposed system consists of three subsystems. The first remote sensing subsystem is based on powerful fluorescent lidars; experimental results on lidar registration of oil pollution of water are reported. The second subsystem uses a network of automatic monitoring stations with contact detectors. The third subsystem is the combined sensor system based on remote and contact technologies.
Quantifying meltwater refreezing along a transect of sites on the Greenland ice sheet
Authors: Cox C. , Humphrey N. , Harper J.
Published: April 2015

Abstract. On the Greenland ice sheet, a significant quantity of surface meltwater refreezes within the firn, creating uncertainty in surface mass balance estimates. This refreezing has the potential to buffer seasonal runoff to future increases in melting, but direct measurement of the process remains difficult. We present a method for quantifying refreezing at point locations using in situ firn temperature observations. A time series of sub-hourly firn temperature profiles were collected over the course of two melt seasons from 2007 to 2009 along a transect of 11 sites in the accumulation zone of Greenland. Seasonal changes in temperature profiles combined with heat flux estimates based on high-temporal-resolution temperature gradients enable us to isolate the heat released by refreezing using conservation of energy. Our method is verified from winter data when no refreezing takes place, and uncertainty is estimated using a Monte Carlo technique. While we limit our method to a subsection of firn between depths of 1 and 10 m, our refreezing estimates appear to differ significantly from model-based estimates. Furthermore, results indicate that a significant amount of refreezing takes place at depths greater than 1 m and that lateral migration of meltwater significantly complicates the relationship between total surface melt and total refreezing.
Numerical simulation of formation and preservation of Ningwu ice cave, Shanxi, China
Authors: Yang S. , Shi Y.
Published: April 2015

Abstract. Ice caves exist in locations where annual average temperature in higher than 0 °C. An example is Ningwu ice cave, Shanxi Province, the largest ice cave in China. In order to quantitatively explain the mechanism of formation and preservation of the ice cave, we use Finite Element Method to simulate the heat transfer process at this ice cave. There are two major control factors. First, there is the seasonal asymmetric heat transfer. Heat is transferred into the ice cave from outside, very inefficiently by conduction in spring, summer and fall. In winter, thermal convection occurs that transfers heat very efficiently out of the ice cave, thus cooling it down. Secondly, ice–water phase change provides a heat barrier for heat transfer into the cave in summer. The calculation also helps to evaluate effects of global warming, tourists, etc. for sustainable development of ice cave as tourism resource. In some other ice caves in China, managers installed air-tight doors at these ice caves entrance intending to "protect" these caves, but this prevent cooling down these caves in winters and these cave ices will entirely melt within tens of years.
Peer Assessment within Hybrid and Online Courses: Students’ View of Its Potential and Performance
Authors: Sullivan Daniel , Watson Sharon
Published: April 2015

The scale and scope of online education increasingly expand. In tandem, interest grows among educators and scholars in understanding the personal and contextual factors that moderate the efficient design and effective delivery of an online course. This paper looks at a theoretically robust method, peer assessment administered by the Canvas learning management system, and evaluates its potential and performance in university-level hybrid and online courses. Cross-sectional data profile students’ views, both prior to as well as post-experience, of aspects of the peer review process. Frequency analyses, mean comparisons, and t-tests highlight students’ initial strong, positive agreement with the potential but then, post-experience, weaker support of the value of peer assessment. Controlling for time and place, in terms of hybrid versus online sections, did not moderate this outcome. Collectively, these results call for refining our interpretation of the utility of peer assessment to promoting student engagement. We evaluate the moderating influence of anonymity and the social dynamic of self-directed learning, particularly given the implications of the “anytime, anyplace” instrumentality of online education. We close with a series of pedagogical recommendations.