bluuebunny/crossref_metadata_2025 huggingface dataset:
IFN-γ Production by Allogeneic Foxp3+ Regulatory T Cells Is Essential for Preventing Experimental Graft-versus-Host Disease
Authors: Koenecke Christian , Lee Chun-Wei , Thamm Kristina , Föhse Lisa , Schafferus Matthias , Mittrücker Hans-Willi , Floess Stefan , Huehn Jochen , Ganser Arnold , Förster Reinhold , Prinz Immo
Published: August 2012

It is emerging that CD4+Foxp3+ regulatory T (Treg) cells can produce the proinflammatory cytokine IFN-γ when stimulated in a Th1 cytokine environment. In this study, we report that Foxp3+ Treg cells readily produced IFN-γ in vivo in a highly inflammatory model of graft-versus-host disease (GVHD) and during a Th1-dominated immune response to intracellular bacteria. Moreover, stimulation in vitro via TCR in the presence of IL-12 alone was sufficient to induce IFN-γ production by Treg cells in a dose-dependent manner. Transfer of donor Treg cells can prevent lethal GVHD; therefore, we used this model as a robust readout for in vivo Treg function. Interestingly, >50% of allogeneic donor, but not residual recipient Foxp3+ Treg cells produced IFN-γ after transplantation, suggesting that this cytokine production was alloantigen specific. These IFN-γ producers were stable Foxp3+ Treg cells because methylation analysis of the Foxp3 gene locus of transferred and reisolated Treg cells during GVHD showed a fully demethylated Treg-specific–demethylated region. Next, we addressed whether IFN-γ production was supporting or rather impairing the immunosuppressive function of Treg cells during GVHD. Blocking of IFN-γ with specific mAb completely abolished the beneficial effect of donor Treg cells. We could further show that only wild-type Treg cells, but not Treg cells from IFN-γ–deficient donor mice, prevented GVHD. This indicated that Treg cell-intrinsic IFN-γ production was required for their protective function. In conclusion, our data show that IFN-γ produced by Foxp3+ Treg cells has essential immune-regulatory functions that are required for prevention of experimental GVHD.
Dietary Folic Acid Promotes Survival of Foxp3+ Regulatory T Cells in the Colon
Authors: Kinoshita Makoto , Kayama Hisako , Kusu Takashi , Yamaguchi Tomoyuki , Kunisawa Jun , Kiyono Hiroshi , Sakaguchi Shimon , Takeda Kiyoshi
Published: August 2012

Dietary compounds as well as commensal microbiota contribute to the generation of a unique gut environment. In this study, we report that dietary folic acid (FA) is required for the maintenance of Foxp3+ regulatory T cells (Tregs) in the colon. Deficiency of FA in the diet resulted in marked reduction of Foxp3+ Tregs selectively in the colon. Blockade of folate receptor 4 and treatment with methotrexate, which inhibits folate metabolic pathways, decreased colonic Foxp3+ Tregs. Compared with splenic Tregs, colonic Tregs were more activated to proliferate vigorously and were highly sensitive to apoptosis. In colonic Tregs derived from mice fed with a FA-deficient diet, expression of anti-apoptotic molecules Bcl-2 and Bcl-xL was severely decreased. A general reduction of peripheral Tregs was induced by a neutralizing Ab against IL-2, but a further decrease by additional FA deficiency was observed exclusively in the colon. Mice fed with an FA-deficient diet exhibited higher susceptibility to intestinal inflammation. These findings reveal the previously unappreciated role of dietary FA in promotion of survival of Foxp3+ Tregs that are in a highly activated state in the colon.
Role of Mincle in Alveolar Macrophage-Dependent Innate Immunity against Mycobacterial Infections in Mice
Authors: Behler Friederike , Steinwede Kathrin , Balboa Luciana , Ueberberg Bianca , Maus Regina , Kirchhof Gabriele , Yamasaki Sho , Welte Tobias , Maus Ulrich A.
Published: August 2012

The role of macrophage-inducible C-type lectin Mincle in lung innate immunity against mycobacterial infection is incompletely defined. In this study, we show that wild-type (WT) mice responded with a delayed Mincle induction on resident alveolar macrophages and newly immigrating exudate macrophages to infection with Mycobacterium bovis bacillus Calmette-Guérin (BCG), peaking by days 14–21 posttreatment. As compared with WT mice, Mincle knockout (KO) mice exhibited decreased proinflammatory mediator responses and leukocyte recruitment upon M. bovis BCG challenge, and they demonstrated increased mycobacterial loads in pulmonary and extrapulmonary organ systems. Secondary mycobacterial infection on day 14 after primary BCG challenge led to increased cytokine gene expression in sorted alveolar macrophages of WT mice, but not Mincle KO mice, resulting in substantially reduced alveolar neutrophil recruitment and increased mycobacterial loads in the lungs of Mincle KO mice. Collectively, these data show that WT mice respond with a relatively late Mincle expression on lung sentinel cells to M. bovis BCG infection. Moreover, M. bovis BCG-induced upregulation of C-type lectin Mincle on professional phagocytes critically shapes antimycobacterial responses in both pulmonary and extrapulmonary organ systems of mice, which may be important for elucidating the role of Mincle in the control of mycobacterial dissemination in mice.
The effects of music relaxation and muscle relaxation techniques on sleep quality and emotional measures among individuals with posttraumatic stress disorder
Authors: Blanaru Monica , Bloch Boaz , Vadas Limor , Arnon Zahi , Ziv Naomi , Kremer Ilana , Haimov Iris
Published: August 2012

Posttraumatic stress disorder (PTSD), an anxiety disorder with lifetime prevalence of 7.8%, is characterized by symptoms that develop following exposure to traumatic life events and that cause an immediate experience of intense fear, helplessness or horror. PTSD is marked by recurrent nightmares typified by the recall of intrusive experiences and by extended disturbance throughout sleep. Individuals with PTSD respond poorly to drug treatments for insomnia. The disadvantages of drug treatment for insomnia underline the importance of non-pharmacological alternatives. Thus, the present study had three aims: first, to compare the efficiency of two relaxation techniques (muscular relaxation and progressive music relaxation) in alleviating insomnia among individuals with PTSD using both objective and subjective measures of sleep quality; second, to examine whether these two techniques have different effects on psychological indicators of PTSD, such as depression and anxiety; and finally, to examine how initial PTSD symptom severity and baseline emotional measures are related to the efficiency of these two relaxation methods. Thirteen PTSD patients with no other major psychiatric or neurological disorders participated in the study. The study comprised one seven-day running-in, no-treatment period, followed by two seven-day experimental periods. The treatments constituted either music relaxation or muscle relaxation techniques at desired bedtime. These treatments were randomly assigned. During each of these three experimental periods, subjects' sleep was continuously monitored with a wrist actigraph (Ambulatory Monitoring, Inc.), and subjects were asked to fill out several questionnaires concerned with a wide spectrum of issues, such as sleep, depression, and anxiety. Analyses revealed a significant increase in objective and subjective sleep efficiency and a significant reduction in depression level following music relaxation. Moreover, following music relaxation, a highly significant negative correlation was found between improvement in objective sleep efficiency and reduction in depression scale. The study‘s findings provide evidence that music relaxation at bedtime can be used as treatment for insomnia among individuals with PTSD.
Pre-service teachers’ views about their mathematics teacher education modules
Authors: Gierdien Faaiz
Published: August 2012

This article reports on the views of intermediate and senior phase pre-service teachers (PSTs) enrolled in mathematics education modules that attempt to teach both content and pedagogy. The PSTs are students in a four-year Bachelor of Education (BEd) model located in a faculty of education. Findings were analysed by means of an analytic framework that takes into account the university–school divide. Findings indicate that the PSTs position themselves in different ways with regard to their preparation for school mathematics teaching. Implications are considered, especially the PSTs’ affective views such as their anxiety and apprehension related to the discursive differences between the content in the university modules and school mathematics.
Semi‐automated image analysis for the identification of bivalve larvae from a Cape Cod estuary
Authors: Thompson Christine M. , Hare Matthew P. , Gallager Scott M.
Published: August 2012

Machine‐learning methods for identifying planktonic organisms are becoming well‐established. Although similar morphologies among species make traditional image identification methods difficult for larval bivalves, species‐specific shell birefringence patterns under polarized light permit identification by color and texture‐based features. This approach uses cross‐polarized images of bivalve larvae, extracts Gabor and color angle features from each image, and classifies images using a Support Vector Machine. We adapted this method, which was established on hatchery‐reared larvae, to identify bivalve larvae from a series of field samples from a Cape Cod estuary in 2009. This method had 98% identification accuracy for four hatchery‐reared species. We used a multiplex polymerase chain reaction (PCR) method to confirm field identifications and to compare accuracies to the software classifications. Image classification of larvae collected in the field had lower accuracies than both the classification of hatchery species and PCR‐based identification due to error in visually classifying unknown larvae and variability in larval images from the field. A six‐species field training set had the best correspondence to our visual classifications with 75% overall agreement and individual species agreements from 63% to 88%. Larval abundance estimates for a time‐series of field samples showed good correspondence with visual methods after correction. Overall, this approach represents a cost‐ and time‐saving alternative to molecular‐based identifications and can produce sufficient results to address long‐term abundance and transport‐based questions on a species‐specific level, a rarity in studies of bivalve larvae.
Measurement of benthic photosynthesis and calcification in flowing‐through seawater with stable carbonate chemistry
Authors: Gao Kunshan , Xu Juntian , Zheng Yangqiao , Ke Caihuan
Published: August 2012

Estimation of photosynthetic or calcification rates of benthic organisms under stable seawater chemistry is important to fathom their capacity of CO2 fixation under constant or controlled levels of pCO2 and acidity of seawater. The flowing‐through system, introduced here, can hold large individuals or colonies and maintain the carbonate chemical parameters stable while photosynthetic or calcification rate is measured based on the assimilation pipe inlet and outlet differences in dissolved O2 concentrations or total alkalinity. The data obtained with this system for macroalgae showed constancy over time under controlled conditions, resulting in higher photosynthetic rates compared with those measured in a closed mode, which caused significant changes in the carbonate system (decreased pCO2 and DIC and increased pH). When the method was applied to measurements of calcification based on the changes in total alkalinity, reliable data were obtained for both coralline algae and oysters. In addition, it can also be applied to measure respiration of both macrophyte and animals and to test the effects of increased pCO2 and current speeds when these factors are controlled under either laboratory or field conditions while exposed to natural solar radiation.
A new method for field measurement of dissolved methane in water using infrared tunable diode laser absorption spectroscopy
Authors: Sepulveda‐Jauregui Armando , Martinez‐Cruz Karla , Strohm Amy , Walter Anthony Katey M. , Thalasso Frédéric
Published: August 2012

Dissolved gas concentration in environmental water samples is usually determined by headspace equilibration (HE) techniques followed by laboratory analyses. This method generally causes a time delay between field sampling and measurements that (i) impedes feedback of results that would otherwise inform field sampling strategies, (ii) may affect the precision of the results due to biological activity or leakage, and (iii) may require logistically complex procedures for transport and storage of samples. The development of an on‐site measurement technique combined with headspace equilibration methods would be beneficial, especially for multiple field measurements in remote areas. In this article, we present a method, based on headspace equilibration but using infrared tunable diode laser absorption spectroscopy (HE‐TDLAS) that allows immediate determination of dissolved gas concentrations in environmental water. HE‐TDLAS method was first tested in the laboratory and compared with a gas chromatography technique. No significant difference was observed between both methods. HETDLAS method was then used during field experiments for the measurement of dissolved methane concentration in 110 water samples from several Alaskan lakes. Dissolved methane concentrations ranging from 0.014 to 20 mg L−1 were successfully measured with standard errors of 28% to 2%, respectively. A quantification limit of 13.6 mg L−1 and an accuracy of 3.6% were established from the statistical analysis. Results suggest that the HETDLAS method is applicable to many aquatic ecosystems, including wastewater treatment facilities, landfills, rice paddies, and freshwater ecosystems, in which dissolved methane typically occurs in the µg to mg L−1 range.
High resolution determination of nanomolar concentrations of dissolved reactive phosphate in ocean surface waters using long path liquid waveguide capillary cells (LWCC) and spectrometric detection
Authors: Zimmer Louise Aastrup , Cutter Gregory A.
Published: August 2012

In the last decade, long path length, low volume, liquid waveguide capillary cells (LWCC) in conjunction with conventional nutrient auto‐analyzers have been applied to determinations of nanomolar levels of phosphate, nitrate, and nitrite in oligotrophic waters. This article reports a high resolution, real‐time, continuous method for nanomolar dissolved reactive phosphate measurements in ocean surface waters with data logging every 30 seconds for up to 16 consecutive hours. Surface seawater is pumped continuously from a shipboard underway tow‐fish unit to a helium gas‐segmented, continuous‐flow, nutrient auto‐analyzer modified with a 250 cm LWCC. To circumvent baseline instability due to reagents, a parallel channel with deionized water (DI) and reagents is run and later subtracted from the sample absorbances. The detection limit is 0.8 nmol/L. The precision (as relative standard deviation) at 5 nmol/L phosphate is 6.1% (n = 5) and 0.8% (n = 5) at 50 nmol/L. We also report an optimized method for discrete samples using a 200 cm LWCC. To minimize any background phosphate concentration in low nutrient seawater used as wash water solution, we use DI water, but increase sample and wash times to achieve plateau‐shaped peaks after the transient wash/sample mixing period. The detection limit is 0.5 nmol/L. The precision at 10 nmol/L phosphate is 1.8% (n = 8) and 0.9% (n = 9) at 60 nmol/L. The two systems have successfully been deployed on the U.S. GEOTRACES 2010 cruise, transecting the upwelling area northwest of Africa and the highly stratified, oligotrophic, subtropical North Atlantic gyre.
The direct effect of aerosols on solar radiation over the broader Mediterranean basin
Authors: Papadimas C. D. , Hatzianastassiou N. , Matsoukas C. , Kanakidou M. , Mihalopoulos N. , Vardavas I.
Published: August 2012

Abstract. For the first time, the direct radiative effect (DRE) of aerosols on solar radiation is computed over the entire Mediterranean basin, one of the most climatically sensitive world regions, using a deterministic spectral radiation transfer model (RTM). The DRE effects on the outgoing shortwave radiation at the top of atmosphere (TOA), DRETOA, on the absorption of solar radiation in the atmospheric column, DREatm, and on the downward and absorbed surface solar radiation (SSR), DREsurf and DREnetsurf, respectively, are computed separately. The model uses input data for the period 2000–2007 for various surface and atmospheric parameters, taken from satellite (International Satellite Cloud Climatology Project, ISCCP-D2), Global Reanalysis projects (National Centers for Environmental Prediction – National Center for Atmospheric Research, NCEP/NCAR), and other global databases. The spectral aerosol optical properties (aerosol optical depth, AOD, asymmetry parameter, gaer and single scattering albedo, ωaer), are taken from the MODerate resolution Imaging Spectroradiometer (MODIS) of NASA (National Aeronautics and Space Administration) and they are supplemented by the Global Aerosol Data Set (GADS). The model SSR fluxes have been successfully validated against measurements from 80 surface stations of the Global Energy Balance Archive (GEBA) covering the period 2000–2007. A planetary cooling is found above the Mediterranean on an annual basis (regional mean DRETOA = −2.4 W m−2). Although a planetary cooling is found over most of the region, of up to −7 W m−2, large positive DRETOA values (up to +25 W m−2) are found over North Africa, indicating a strong planetary warming, and a weaker warming over the Alps (+0.5 W m−2). Aerosols are found to increase the absorption of solar radiation in the atmospheric column over the region (DREatm = +11.1 W m−2) and to decrease SSR (DREsurf = −16.5 W m−2 and DREnetsurf−13.5 W m−2) inducing thus significant atmospheric warming and surface radiative cooling. The calculated seasonal and monthly DREs are even larger, reaching −25.4 W m−2 (for DREsurf). Within the range of observed natural or anthropogenic variability of aerosol optical properties, AOD seems to be the main responsible parameter for modifications of regional aerosol radiative effects, which are found to be quasi-linearly dependent on AOD, ωaer and gaer.
Understanding the aqueous phase ozonolysis of isoprene: distinct product distribution and mechanism from the gas phase reaction
Authors: Wang H. L. , Huang D. , Zhang X. , Zhao Y. , Chen Z. M.
Published: August 2012

Abstract. The aqueous phase reaction of volatile organic compounds (VOCs) has not been considered in most analyses of atmospheric chemical processes. However, some experimental evidence has shown that, compared to the corresponding gas phase reaction, the aqueous chemical processes of VOCs in the bulk solutions and surfaces of ambient wet particles (cloud, fog, and wet aerosols) may potentially contribute to the products and formation of secondary organic aerosol (SOA). In the present study, we performed a laboratory experiment of the aqueous ozonolysis of isoprene at different pHs (3–7) and temperatures (4–25 °C). We detected three important kinds of products, including carbonyl compounds, peroxide compounds, and organic acids. Our results showed that the molar yields of these products were nearly independent of the investigated pHs and temperatures, those were (1) carbonyls: 56.7 ± 3.7 % formaldehyde, 42.8 ± 2.5 % methacrolein (MAC), and 57.7 ± 3.4 % methyl vinyl ketone (MVK); (2) peroxides: 53.4 ± 4.1 % hydrogen peroxide (H2O2) and 15.1 ± 3.1 % hydroxylmethyl hydroperoxide (HMHP); and (3) organic acids: undetectable (<1 % estimated by the detection limit). Based on the amounts of products formed and the isoprene consumed, the total carbon yield was estimated to be 94.8 ± 4.1 %. This implied that most of the products in the reaction system were detected. The combined yields of both MAC + MVK and H2O2 + HMHP in the aqueous isoprene ozonolysis were much higher than those observed in the corresponding gas phase reaction. We suggest that these unexpected high yields of carbonyls and peroxides are related to the greater capability of condensed water, compared to water vapor, to stabilize energy-rich Criegee radicals. This aqueous ozonolysis of isoprene (and possibly other biogenic VOCs) could potentially occur on the surfaces of ambient wet particles and plants. Moreover, the high-yield carbonyl and peroxide products might provide a considerable source of aqueous phase oxidants and SOA precursors.
Diel cycles of isoprenoids in the emissions of Norway spruce, four Scots pine chemotypes, and in Boreal forest ambient air during HUMPPA-COPEC-2010
Authors: Yassaa N. , Song W. , Lelieveld J. , Vanhatalo A. , Bäck J. , Williams J.
Published: August 2012

Abstract. Branch enclosure based emission rates of monoterpenes and sesquiterpenes from four Scots pines (Pinus sylvestris) and one Norway spruce (Picea abies), as well as the ambient mixing ratios of monoterpenes were determined during the HUMPPA-COPEC 2010 summer campaign. Differences in chemical composition and in emission strength were observed between the different trees, which confirmed that they represented different chemotypes. The chemotypes of Scots pine can be classified according to species with high, no and intermediate content of Δ-3-carene. The "non-Δ-3-carene" chemotype was found to be the strongest emitter of monoterpenes. From this chemotype, β-myrcene, a very reactive monoterpene, was the dominant species accounting for more than 32 % of the total emission rates of isoprenoids followed by β-phellandrene (~27%). Myrcene fluxes ranged from 0.8 to 24 μg g−1 (dw) h−1. α-Farnesene was the dominant sesquiterpene species, with average emission rates of 318 ng g−1 (dw) h−1. In the high Δ-3-carene chemotype, more than 48% of the total monoterpene emission was Δ-3-carene. The average Δ-3-carene emission rate (from chemotype 3), circa 609 ng g−1 (dw) h−1 reported here is consistent with the previously reported summer season value. Daily maximum temperatures varied between 20 and 35 °C during the measurements. The monoterpene emissions from spruce were dominated by limonene (35%), β-phellandrene (15%), α-pinene (14%) and eucalyptol (9%). Total spruce monoterpene emissions ranged from 0.55 up to 12.2 μg g−1 (dw) h−1. Overall the total terpene flux (monoterpenes + sesquiterpenes) from all studied tree species varied from 230 ng g−1 (dw) h−1 up to 66 μg g−1 (dw) h−1. Total ambient monoterpenes (including α-pinene, Δ-3-carene, β-pinene and β-myrcene) measured during the campaign varied in mixing ratio from a few pptv to over one ppbv. The most abundant biogenic VOC measured above the canopy were α-pinene and Δ-3-carene, and these two compounds together contributed more than 50% of the total monoterpenes. The ambient data reflect the emission rate, atmospheric reactivity and tree type abundance. The diel cycles of isoprenoid mixing ratios showed high levels during the night-time which is consistent with continued low nocturnal emission and a low and stable boundary layer. The chirality of α-pinene was dominated by (+)-enantiomers both in the direct emission and in the atmosphere. The two highest emitters showed no enantiomeric preference for α-pinene emissions, whereas the two lowest emitting pines emitted more (+)-enantiomer. The spruce emissions were dominated by (−)-enantiomer. The exceptionally hot temperatures in the summer of 2010 led to relatively strong emissions of monoterpenes, greater diversity in chemical composition and high ambient mixing ratios.
Quantifying the deep convective temperature signal within the tropical tropopause layer (TTL)
Authors: Paulik L. C. , Birner T.
Published: August 2012

Abstract. Dynamics on a vast range of spatial and temporal scales, from individual convective plumes to planetary-scale circulations, play a role in driving the temperature variability in the tropical tropopause layer (TTL). Here, we aim to better quantify the deep convective temperature signal within the TTL using multiple datasets. First, we investigate the link between ozone and temperature in the TTL using the Southern Hemisphere Additional Ozonesondes (SHADOZ) dataset. Low ozone concentrations in the TTL are indicative of deep convective transport from the boundary layer. We confirm the usefulness of ozone as an indicator of deep convection by identifying a typical temperature signal associated with reduced ozone events: mid and upper tropospheric warming and TTL cooling. We quantify these temperature signals using two diagnostics: (1) the "ozone minimum" diagnostic, which has been used in previous studies and identifies the upper tropospheric minimum ozone concentration as a proxy for the level of main convective outflow; and (2) the "ozone mixing height", which we introduce in order to identify the maximum altitude in a vertical ozone profile up to which reduced ozone concentrations, typical of transport from the boundary layer are observed. Results indicate that the ozone mixing height diagnostic better separates profiles with convective influence than the ozone minimum diagnostic. Next, we collocate deep convective clouds identified by CloudSat 2B-CLDCLASS with COSMIC GPS temperature profiles. We find a robust large-scale deep convective TTL temperature signal, that is persistent in time. However, it is only the convective events that penetrate into the upper half of the TTL that have a significant impact on TTL temperature. A distinct seasonal difference in the spatial scale and the persistence of the temperature signal is identified. Deep-convective cloud top heights are found to be well described by the level of neutral buoyancy.
Direct and disequilibrium effects on precipitation in transient climates
Authors: McInerney D. , Moyer E.
Published: August 2012

Abstract. Climate models are in broad agreement that global precipitation increases with surface temperature as atmospheric CO2 concentrations rise, but recent studies have shown that climates that are not yet in equilibrium exhibit additional "transient precipitation effects". In conditions of rising CO2, for example, precipitation at a given temperature is suppressed relative to its equilibrium value. Some authors argue that the primary driver of these effects is ocean heat uptake, but most recent studies assume that they result from some direct radiative effect. We show here that global precipitation and temperature anomalies are insufficient to resolve mechanisms, since the conventional "fast/slow" representation of transient precipitation effects is degenerate with a "disequilibrium" representation that posits control only by ocean heat uptake. We use regional anomalies instead to show in multiple ways that ocean heat uptake is the dominant driver of transient precipitation effects in CO2-forced climates. Precipitation suppression appears predominantly over the ocean, with response over land of the opposite sign. The coefficients of a disequilibrium representation are uncorrelated, suggesting that they capture physically meaningful processes, while those of a fast/slow representation are highly correlated. Further, the regional patterns of transient precipitation response are highly similar for both CO2 and solar forcing, with a relatively small and homogeneous offset between them. Examination of the surface energy budget allows us to conclude that energy balance in solar-forced climates is achieved by the superposition of both disequilibrium and direct processes. Our results highlight the importance of using regional information rather than global aggregates for understanding the physics of transient climate change and its impacts on societies.
The effect of coal-fired power-plant SO2 and NOx control technologies on aerosol nucleation in the source plumes
Authors: Lonsdale C. R. , Stevens R. G. , Brock C. A. , Makar P. A. , Knipping E. M. , Pierce J. R.
Published: August 2012

Abstract. Nucleation in coal-fired power-plant plumes can greatly contribute to particle number concentrations near source regions. The changing emissions rates of SO2 and NOx due to pollution-control technologies over recent decades may have had a significant effect on aerosol formation and growth in the plumes, with ultimate implications for climate and human health. We use the System for Atmospheric Modeling (SAM) large-eddy simulation model with the TwO-Moment Aerosol Sectional (TOMAS) microphysics algorithm to model the nucleation in plumes of coal-fired plants. We test a range of cases with varying emissions to simulate the implementation of emissions-control technologies between 1997 and 2010. For the W.A. Parish power plant (near Houston, TX) during this time period, NOx emissions were reduced by ~90%, while SO2 emissions decreased by ~30%. Increases in plume OH (due to the reduced NOx) produced enhanced SO2 oxidation and particle nucleation despite the reduction in SO2 emissions. These results suggest that NOx emissions may strongly regulate particle nucleation and growth in power-plant plumes. Comparison of model results with airborne measurements made in the W.A. Parish power-plant plume in 2000 and 2006 confirm the importance of NOx emissions on new particle formation, yet also highlight the substantial effect of background aerosol loadings on this process. A wide range of NOx and SO2 emissions were modeled to understand how they affect particle formation in the plume. Particle formation generally increases with SO2 emission, while NOx shows two different regimes: increasing particle formation with increasing NOx under low-NOx emissions and decreasing particle formation with increasing NOx under high-NOx emissions. Finally, we calculate emissions statistics of 330 coal-fired power plants in the US in 1997 and 2010, and the model results show a median decrease of 19% in particle formation ratesfrom 1997 to 2010 (whereas the W.A. Parish case study showed an increase). These results suggest that there may be important climate implications of power-plant controls due to changes in plume chemistry and microphysics. More extensive plume measurements for a range of emissions of SO2 and NOx and in varying background aerosol conditions are needed to better quantify these effects.
Design and performance of a Nafion dryer for continuous operation at CO2 and CH4 air monitoring sites
Authors: Welp L. R. , Keeling R. F. , Weiss R. F. , Paplawsky W. , Heckman S.
Published: August 2012

Abstract. In preparation for the routine deployment of the Earth Networks greenhouse gas monitoring network, we have designed and tested a simple method for drying ambient air to below 0.2% mole fraction H2O using a Nafion dryer. The inlet was designed for use with a Picarro model G2301 cavity ring down spectrometer (CRDS) CO2/CH4/H2O analyzer. The analyzer measures water vapor mixing ratio at the same frequency as CO2 and CH4 and then corrects for the dilution and peak broadening effects of H2O on the CO2 and CH4 mixing ratios. This analyzer is remarkably stable and performs well on water vapor correction tests, but there is potentially an added benefit of reducing the dependence on the H2O correction for long term field measurement programs. Substantially lowering the amount of H2O in the sample can reduce uncertainties in the applied H2O corrections by an order of magnitude or more, and eliminate the need to determine an instrument-specific H2O correction factor and to verify its stability over time. Our Nafion drying inlet system takes advantage of the extra capacity of the analyzer pump to redirect 30% of the dry gas exiting the Nafion to the outer shell side of the dryer and has no consumables. We tested the Nafion dryer against a cryotrap (−95 °C) method for removing H2O and found that it does not significantly alter the CO2 and CH4 dry mixing ratios of the sample gas. Systematic differences between the drying methods were at the level of 0.05 ppm in CO2 and 0.1 ppb in CH4 for the wet-air tests, well within the WMO compatibility guidelines.
Spatial and temporal variability of nitrous oxide emissions in a mixed farming landscape of Denmark
Authors: Schelde K. , Cellier P. , Bertolini T. , Dalgaard T. , Weidinger T. , Theobald M. R. , Olesen J. E.
Published: August 2012

Abstract. Nitrous oxide (N2O) emissions from agricultural land are variable at the landscape scale due to variability in land use, management, soil type, and topography. A field experiment was carried out in a typical mixed farming landscape in Denmark, to investigate the main drivers of variations in N2O emissions, measured using static chambers. Measurements were made over a period of 20 months, and sampling was intensified during two weeks in spring 2009 when chambers were installed at ten locations or fields to cover different crops and topography and slurry was applied to three of the fields. N2O emissions during spring 2009 were relatively low, with maximum values below 20 ng N m−2 s−1. This applied to all land use types including winter grain crops, grasslands, meadows, and wetlands. Slurry application to wheat fields resulted in short-lived two-fold increases in emissions. The moderate N2O fluxes and their moderate response to slurry application were attributed to dry soil conditions due to the absence of rain during the four previous weeks. Cumulative annual emissions from two arable fields that were both fertilized with mineral fertilizer and manure were large (17 kg N2O-N ha−1 yr−1 and 5.5 kg N2O-N ha−1 yr−1) during the previous year when soil water conditions were favourable for N2O production during the first month following fertilizer application. Our findings confirm the importance of weather conditions as well as nitrogen management on N2O fluxes.
Determination of the molecular signature of fossil conifers by experimental palaeochemotaxonomy – Part 1: The Araucariaceae family
Authors: Lu Y. , Hautevelle Y. , Michels R.
Published: August 2012

Abstract. Several extant species of the Araucariaceae family (one of the families of conifers) were invested for the experimental artificial maturation by confined pyrolysis, in order to realize the transformation of biomolecules to geomolecules in laboratory conditions. The experimental study of diagenetized molecular signatures of the Araucariaceae species (common, inter- and infra-generic characteristics) allow to complete our knowledge in botanical palaeochemotaxonomy. Such knowledge is relevant to the reconstitution of palaeoflora and palaeoclimatic reconstruction, archaeology and environmental studies. In this work, major carbon skeleton types of Araucariaceae are detected in the organic solvent extracts of fresh and pyrolyzed plants using gas chromatography-mass spectrometry. The results show that all species of Araucariaceae are firstly characterized by a predominance of saturated tetracyclic diterpenoids. Moreover, the Araucaria genus shows a high relative abundance of bicyclic sesquiterpenoids, particularly compounds of the cadalane-type compounds accompanied by those of eudesmane-type, bisabolane-type as well as chamazulene, pentamethyl-dihydroindenes. Diterpenoids are of the labdane-type, isopimarane, abietane-type (essentially derived from abietanoic acids) as well as isohexyl alkylaromatic hydrocarbons. Compared to the tetracyclic diterpenoids, these compounds show a relatively lower abundance, reaching trace levels in the case of saturated abietanes. Distribution of sesqui- and diterpenoids of Agathis shows some similarities to that of Araucaria, with the exception of one species, in which the tetracyclic compounds are absent and the abietane-type (essentially derived from abietanoic acids) predominant. High similarities between the Wollemia and Araucaria genera are observed. Both are characterized by some high relative abundance of tetracyclic compounds with no predominance of other specific diterpenoids.
IMAGE-BASED 3D RECONSTRUCTION AND ANALYSIS FOR ORTHODONTIA
Authors: Knyaz V. A.
Published: August 2012

Abstract. Among the main tasks of orthodontia are analysis of teeth arches and treatment planning for providing correct position for every tooth. The treatment plan is based on measurement of teeth parameters and designing perfect teeth arch curve which teeth are to create after treatment. The most common technique for teeth moving uses standard brackets which put on teeth and a wire of given shape which is clamped by these brackets for producing necessary forces to every tooth for moving it in given direction. The disadvantages of standard bracket technique are low accuracy of tooth dimensions measurements and problems with applying standard approach for wide variety of complex orthodontic cases. The image-based technique for orthodontic planning, treatment and documenting aimed at overcoming these disadvantages is proposed. The proposed approach provides performing accurate measurements of teeth parameters needed for adequate planning, designing correct teeth position and monitoring treatment process. The developed technique applies photogrammetric means for teeth arch 3D model generation, brackets position determination and teeth shifting analysis.
Recurring features of extreme autumnall rainfall events on the Veneto coastal area
Authors: Barbi A. , Monai M. , Racca R. , Rossa A. M.
Published: August 2012

Abstract. Recent recurring episodes of heavy flash flood-producing rainfall events on the Veneto coastal area have renewed the interest in documenting the frequency and key dynamical ingredients of such events. A climatological analysis of the precipitation in Veneto reveals that, in comparison with the rest of the region, the coastal area is characterized by fewer rain days, lower rainfall accumulations, yet more days with heavy precipitation. If set in relation to the yearly rainfall, daily accumulation can reach values as high as 40% of the yearly total rainfall, more regularly between 15% and 30%, often in periods of 12 h or less. Four such heavy rainfall events were analyzed and synthetically described to highlight key ingredients which appear instrumental in producing the high rainfall accumulations. These comprise an upper-level trough elongating or cutting off into the Western Mediterranean basin after a period of one to two weeks of anticyclonic fair weather conditions with temperatures above normal. The moisture supply over the Adriatic onto north-eastern Italy is favoured by above normal sea surface temperatures, enhanced advection by a surface low in the Gulf of Genoa, and in three of the four cases, an additional surface low over southern Italy. The air flows associated with the upper-level trough for the cases discussed were of moderate to weak intensity, and convectively conditionally unstable. The flow intensity was such that the lower tropospheric portion was blocked by and forced to flow around the Alpine barrier, i.e. manifesting as a north-easterly, low-level flow over much of the north-eastern Italian plains. This blocked flow seemed to interact with the larger-scale synoptic flow to form a distinct and persistent low-level convergence in the area of the Veneto coast. It is suggested that these low-level convergence patterns are key in releasing the convective instability present in the larger-scale flow just on the Veneto coastal area. Hereby, it is the synoptic rather than the convective setting which dictated the observed timescales of intense rainfall. Therefore, the convective rainfall rates paired with the synoptic durations combine to produce the exceptionally high rainfall accumulations observed. Cases like these are significant contributors to forming the coastal precipitation climatology, which for this area is found to be distinctly different than for the rest of the region in terms of precipitation concentration.
Relationship between seismicity and water level in the Enguri high dam area (Georgia) using the singular spectrum analysis
Authors: Telesca L. , Matcharasvili T. , Chelidze T. , Zhukova N.
Published: August 2012

Abstract. The declustered seismic catalog from 1965 to 2010 around the Enguri high dam reservoir in western Georgia was analyzed using the singular spectrum analysis (SSA) technique in order to investigate the relationship of local seismicity with the reservoir water variations. In particular, the seismic activity was analyzed in two periods: a "reference" period, from 1965 to 1970, before the start of dam building in 1971; and an "active" period, from 1978 to 2010, in which the influence of the reservoir was significantly effective on the seismic activity (since the first flooding of the dam occurred in 1978). The SSA was applied to both the monthly number of earthquakes and the time series of the monthly mean of the water level. The first four reconstructed components explained most of the total variance in both seismicity and water level. Clear signatures of the annual oscillation linked with the loading/unloading operations of the dam are present in the periodogram of the second and the third reconstructed components of the seismic activity during the "active" period. Such annual cycle is absent in the periodogram of the reconstructed components of the seismic activity during the "reference" period. This is a clear indication of the reservoir-induced character of the seismicity around the Enguri dam.
Glacial lake mapping with very high resolution satellite SAR data
Authors: Strozzi T. , Wiesmann A. , Kääb A. , Joshi S. , Mool P.
Published: August 2012

Abstract. Floods resulting from the outbursts of glacial lakes are among the most far-reaching disasters in high mountain regions. Glacial lakes are typically located in remote areas and space-borne remote sensing data are an important source of information about the occurrence and development of such lakes. Here we show that very high resolution satellite Synthetic Aperture Radar (SAR) data can be employed for reliably mapping glacial lakes. Results in the Alps, Pamir and Himalaya using TerraSAR-X and Radarsat-2 data are discussed in comparison to in-situ information, and high-resolution satellite optical and radar imagery. The performance of the satellite SAR data is best during the snow- and ice-free season. In the broader perspective of hazard management, the detection of glacial lakes and the monitoring of their changes from very high-resolution satellite SAR intensity images contributes to the initial assessment of hazards related to glacial lakes, but a more integrated, multi-level approach needs also to include other relevant information such as glacier outlines and outline changes or the identification of unstable slopes above the lake and the surrounding area, information types to which SAR analysis techniques can also contribute.
Estimation of positive sum-to-one constrained zooplankton grazing preferences with the DEnKF: a twin experiment
Authors: Simon E. , Samuelsen A. , Bertino L. , Dumont D.
Published: August 2012

Abstract. We consider the estimation of the grazing preferences parameters of zooplankton in ocean ecosystem models with ensemble-based Kalman filters. These parameters are introduced to model the relative diet composition of zooplankton that consists of phytoplankton, small size-classes of zooplankton and detritus. They are positive values and their sum is equal to one. However, the sum-to-one constraint cannot be guaranteed by ensemble-based Kalman filters when parameters are bounded. Therefore, a reformulation of the parameterization is proposed. We investigate two types of variable transformations for the estimation of positive sum-to-one constrained parameters that lead to the estimation of a new set of parameters with normal or bounded distributions. These transformations are illustrated and discussed with twin experiments performed with the 1-D coupled model GOTM-NORWECOM with Gaussian anamorphosis extensions of the deterministic ensemble Kalman filter (DEnKF).
Greenland ice sheet albedo feedback: thermodynamics and atmospheric drivers
Authors: Box J. E. , Fettweis X. , Stroeve J. C. , Tedesco M. , Hall D. K. , Steffen K.
Published: August 2012

Abstract. Greenland ice sheet mass loss has accelerated in the past decade responding to combined glacier discharge and surface melt water runoff increases. During summer, absorbed solar energy, modulated at the surface primarily by albedo, is the dominant factor governing surface melt variability in the ablation area. Using satellite-derived surface albedo with calibrated regional climate modeled surface air temperature and surface downward solar irradiance, we determine the spatial dependence and quantitative impact of the ice sheet albedo feedback over 12 summer periods beginning in 2000. We find that, while albedo feedback defined by the change in net solar shortwave flux and temperature over time is positive over 97% of the ice sheet, when defined using paired annual anomalies, a second-order negative feedback is evident over 63% of the accumulation area. This negative feedback damps the accumulation area response to warming due to a positive correlation between snowfall and surface air temperature anomalies. Positive anomaly-gauged feedback concentrated in the ablation area accounts for more than half of the overall increase in melting when satellite-derived melt duration is used to define the timing when net shortwave flux is sunk into melting. Abnormally strong anticyclonic circulation, associated with a persistent summer North Atlantic Oscillation extreme since 2007, enabled three amplifying mechanisms to maximize the albedo feedback: (1) increased warm (south) air advection along the western ice sheet increased surface sensible heating that in turn enhanced snow grain metamorphic rates, further reducing albedo; (2) increased surface downward shortwave flux, leading to more surface heating and further albedo reduction; and (3) reduced snowfall rates sustained low albedo, maximizing surface solar heating, progressively lowering albedo over multiple years. The summer net infrared and solar radiation for the high elevation accumulation area approached positive values during this period. Thus, it is reasonable to expect 100% melt area over the ice sheet within another similar decade of warming.
An analysis of present and future seasonal Northern Hemisphere land snow cover simulated by CMIP5 coupled climate models
Authors: Brutel-Vuilmet C. , Ménégoz M. , Krinner G.
Published: August 2012

Abstract. The 20th century seasonal Northern Hemisphere land snow cover as simulated by available CMIP5 model output is compared to observations. On average, the models reproduce the observed snow cover extent very well, but the significant trend towards a~reduced spring snow cover extent over the 1979–2005 is underestimated. We show that this is linked to the simulated Northern Hemisphere extratropical land warming trend over the same period, which is underestimated, although the models, on average, correctly capture the observed global warming trend. There is a good linear correlation between hemispheric seasonal spring snow cover extent and boreal large-scale annual mean surface air temperature in the models, supported by available observations. This relationship also persists in the future and is independent of the particular anthropogenic climate forcing scenario. Similarly, the simulated linear correlation between the hemispheric seasonal spring snow cover extent and global mean annual mean surface air temperature is stable in time. However, the sensitivity of the Northern Hemisphere spring snow cover to global mean surface air temperature changes is underestimated at present because of the underestimate of the boreal land temperature change amplification.