bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Substrate Nature and Electrolysis Modes on Ultramicron and Nanosized Electrolytic Powders Formation Regularities
Authors: Lipkin V.M. , Berezhnoi Y.M. , Lipkin M.S.
Published: February 2016

This article presents the research on the effect of substrate nature and electrolysis modes on ultramicron and nanosized electrolytic powders formation regularities. It was found that the preliminarily electropolishing of titanium cathode in combination with impulse electrolysis mode for nickel and copper powders obtaining provides for the predomination of nanosized fraction. The presence of water soluble polymers in the electrolyte for copper powder obtaining, polyvinylpyrrolidone (PVP) and polyacrilamide (PAA) allows forming stable dendritic powders with low agglomeration. Using of powders stabilized by polymers allows obtaining compositions with uniform particle distribution across the whole volume of the sample which provides for heightened wear resistance of composition materials.
Surface Hardening of Parts Arc
Authors: Korolkova L.I. , Mashrabov N.M.
Published: February 2016

The paper presents the results of studies aimed at justifying and developing the ways and means of cylindrical parts made of hardenable alloys surface hardening by heating of the electric arc between the inert electrode and the element. The shapes of electrode sharpening and the position of the electrode relative to the element are substantiated. The sequence of surface hardening operations is revealed and the critical rate of cooling is determined and its value is proved with numerical experiments. It was necessary to develop a program for calculating temperature fields in details, with a difference-differential scheme obtained from a combination of explicit and implicit schemes being developed for the first time. A number of investigations were conducted to determine the mechanical properties, the residual stresses, the fatigue resistance, the hardness and the microstructure of hardened layers. As a result, the surface hardening technology is recommended for reconditioning and manufacturing cylindrical machine elements.
Methods of Increasing the Speed of the Many-Arc Welding
Authors: Ulanov A.M. , Ivanov Mikhail Alekhsandrovich
Published: February 2016

Many-arc submerged welding is used weld thick and long seams of welded steel structures. This article describes a method for increasing the speed of the many-arc welding, with evidence from the parametrical calculation of the four-arc welding mode, using the basic mathematical model of the WeldCalc software. First of all, mathematical model coefficients are calculated based on the existing weld mode. This article presents data for four-arc welding of a 28 mm thick plate. The obtained coefficients are entered in WeldCalc, which checks the compliance of the calculated welding heat input and the actual current while the sample is welded. In case of the values of heat input are discrepant, the software adjusts the coefficients. Data are corrected and and the mathematical model is adjusted according to the participation share coefficient of each arc and to the Ku coefficients of the voltage for each arc. After the welding mode is successfully reconstructed, the welding speed is increased. Thus the parameters of welding mode are changed to increase the aggregate capacity of the power source, but the heat input of welding is not changed. In order to check the new mode, the researchers have welded the rest sample and checked its geometrical dimensions of the joints (height, width, depth of penetration, square of the weld seam). The obtained results are satisfactory.
Surface Modification by Vacuum Arc Plasma Source
Authors: Kostrin D.K. , Lisenkov A.A.
Published: February 2016

In this article features of application of the vacuum arc discharge for modification of surfaces are considered. The complication of o this process simulation due to its complexity and tight correlation between different parameters is explained. The mathematical model describing the interaction of a plasma flux with controlling system is offered. The need of cleaning plasma flux from drop fraction in the process of metal coatings deposition is shown. The properties of coatings received by means of a vacuum arc method are considered.
Growth of Lead and Aluminum Substituted Barium Hexaferrite Single Crystals from Lead Oxide Flux
Authors: Vinnik D.A. , Gudkova S.A. , Niewa R.
Published: February 2016

Lead and aluminum substituted barium hexaferrite (Ba,Pb)Fe12–хAlхO19 single crystals were grown from lead oxide flux at 1260 °C as hexagonal plates with sizes of about 2 mm. A maximum substitution level of x = 4.82 was achieved for the first time for bulk single crystals. The variation of the unit cell parameters with Al content is in good agreement with literature data on exclusively Al substituted barium hexaferrite, while the substitution of Ba by Pb has hardly any influence. Similarly, Pb has only a negligible influence on the magnetic properties, while Al substitution significantly reduces the saturation magnetization in a very similar manner as known from Pb-free barium hexaferrite.
On the Interaction of Calcium and Oxygen in Liquid Iron
Authors: Mikhailov G.G. , Zherebtsov D.A.
Published: February 2016

The parameters of calcium and oxygen interaction in liquid iron are revised. The Vagner parameter values of several hundreds or dozens are proved to be wrong. The recommended value for the constant for the reaction of dissolved calcium and oxygen forming solid calcia is /CaO/=[Ca]+[O] is: lgK/CaO/=-34100/T + 13.46. Vagner parameter for the interaction of Ca and O in liquid iron should be expressed in units (we used =–1.41), not in hundreds. The equilibrium diagram of calcium and oxygen content in liquid iron is calculated at 1550-1700 °C and 0.00001-0.1 mass % Ca. The minimum oxygen content possible to be achieved at 1550 °C and 1 atm is about 0.001 mass %.
Pressure Dependent Magnetization of Arc Discharge Fe–C Soot
Authors: Novopashin S.A. , Demin N.A. , Zaikovskii A.V.
Published: February 2016

This Composite Fe-C anode sputtering in a low-pressure arc discharge has been used to produce Fe-containing nanoparticles on a carbon matrix. Magnetic susceptibility as a function of background pressure has been measured. The data obtained showed the complex, no-monotonous dependency. The material synthesized at optimal pressure (maximal value of magnetic susceptibility) was investigated by means of transmission electron microscopy, X-ray diffraction and magnetometry. Size distribution function of iron containing nanoparticles has been measured. Chemical composition includes iron, iron carbide and carbon soot. Saturation magnetization have been measured and it was shown that the synthesized material is superparamagnetic. The physical processes resulting in the complex behavior of magnetic susceptibility are discussed.
Occurrence of bacteria species responsible for vibriosis in shrimp pond culture systems in Sri Lanka and assessment of the suitable control measures
Authors: Heenatigala P.P.M. , Fernando M.U.L.
Published: February 2016

Shrimp culture in Sri Lanka is continuously affected by bacterial infections and most symptoms agree with the disease called vibriosis. Therefore a bacteriological study was undertaken in shrimp farms to identify the diversity of pathogenic Vibrio species, favorable environmental conditions for them and sensitivity to antibiotics to control them.Water and infected animals from shrimp farms of the Western and North Western provinces were screened for Vibrio. Conventional methods were used for presumptive identification of isolated bacteria. Water quality was analyzed by spectophotometric methods. Disk diffusion technique was used to evaluate antibiotic sensitivity. During the study, 40 bacteria isolates belonging to the family Vibrionaceae were recorded. Of those, 24 isolates belonged to Vibrio species which are responsible for vibriosis in shrimps. Those were Vibrio alginolyticus, V. parahaemolyticus, V. damsela, and V. anguillarum. Most frequently isolated species was V. parahaemolyticus. All Vibrio isolates were found to be resistant to Ampicillin, Gentamycin, Oxytetracyclin, Chloramphenicol, Trimethoprim and Kanamicin, which are commonly used antibiotics in aquaculture. Water quality conditions indicated that the alkaline pH conditions and high salinity and ammonia levels favour the occurrence of high vibrio counts.Results indicate that the application of antibiotics for the control of vibriosis in shrimp farms has limited effectiveness due to the development of resistant bacterial strains and environmental management is the best management intervention that can be used to control this disease.
Size-dependent dietary shifts in Chitala ornata (Osteichthyes; Notopteridae), an accidentally introduced exotic species in Sri Lanka
Authors: Shirantha R.R.A. Ramani
Published: February 2016

Food and feeding biology and some morphological adaptation of an exotic fish species Chitala ornata in a riverine habitat in Sri Lanka was studied from March 2003 to July 2004 to investigate its size-dependent dietary shifts. The stomach contents of C. ornata were volumetrically analyzed and relative abundance of different food categories of different length groups was quantified. There is a marked dietary shift from predominantly herbivory during juvenile stage to piscivory at adult stage. Indigenous cyprinid species are prey organisms and as such, C. ornata possibly poses significant negative impacts on native fish populations as well as other aquatic fauna.
Anticommensal Responses Are Associated with Regulatory T Cell Defect in Autoimmune Polyendocrinopathy–Candidiasis–Ectodermal Dystrophy Patients
Authors: Hetemäki Iivo , Jarva Hanna , Kluger Nicolas , Baldauf Hanna-Mari , Laakso Sini , Bratland Eirik , Husebye Eystein S. , Kisand Kai , Ranki Annamari , Peterson Pärt , Arstila T. Petteri
Published: February 2016

Autoimmune polyendocrinopathy–candidiasis–ectodermal dystrophy (APECED) is a monogenic autoimmune disease caused by mutations in the AIRE gene. Although mainly an endocrine disease, a substantial fraction of patients have gastrointestinal manifestations. In this study, we have examined the role of anticommensal responses and their regulation. APECED patients had increased levels of Abs against Saccharomyces cerevisiae (p < 0.0001) and against several species of commensal gut bacteria, but not against species predominantly associated with other locations. The anticommensal Ab levels did not correlate with gastrointestinal autoantibodies, neutralizing anti–IL-17 or –IL-22 Abs, or gastrointestinal symptoms, although scarcity of the available clinical data suggests that further study is required. However, the anti–S. cerevisiae Ab levels showed a significant inverse correlation with FOXP3 expression levels in regulatory T cells (Treg), previously shown to be dysfunctional in APECED. The correlation was strongest in the activated CD45RO+ population (ρ = −0.706; p < 0.01). APECED patients also had decreased numbers of FOXP3+ cells in gut biopsies. These results show that APECED patients develop early and sustained responses to gut microbial Ags in a pattern reminiscent of Crohn’s disease. This abnormal immune recognition of gut commensals is linked to a systemic Treg defect, which is also reflected as a local decrease of gut-associated Treg. To our knowledge, these data are the first to show dysregulated responses to non-self commensal Ags in APECED and indicate that AIRE contributes to the regulation of gut homeostasis, at least indirectly. The data also raise the possibility of persistent microbial stimulation as a contributing factor in the pathogenesis of APECED.
T-bet Promotes Acute Graft-versus-Host Disease by Regulating Recipient Hematopoietic Cells in Mice
Authors: Fu Jianing , Wu Yongxia , Nguyen Hung , Heinrichs Jessica , Schutt Steven , Liu Yuejun , Liu Chen , Jin Junfei , Anasetti Claudio , Yu Xue-Zhong
Published: February 2016

Beyond its critical role in T cells, T-bet regulates the functions of APCs including dendritic cells and B cells, as well as NK cells. Given that recipient APCs are essential for priming allogeneic T cells and recipient NK or T cells are able to reject allogeneic donor cells, we evaluated the role of T-bet on the host in acute graft-versus-host disease (GVHD) using murine models of allogeneic bone marrow transplantation. T-bet−/− recipients developed significantly milder GVHD than their wild type counterparts in MHC-mismatched or CD4-depedent minor histocompatibility Ag–mismatched models. Allogeneic donor T cells, in particular, CD4 subset, significantly reduced IFN-γ production, proliferation and migration, and caused less injury in liver and gut of T-bet−/− recipients. We further observed that T-bet on recipient hematopoietic cells was primarily responsible for the donor T cell response and pathogenicity in GVHD. T-bet−/− dendritic cells expressed higher levels of Trail, whereas they produced lower levels of IFN-γ and IL-12/23 p40, as well as chemokine CXCL9, resulting in significantly higher levels of apoptosis, less priming, and infiltration of donor T cells. Meanwhile, NK cells in T-bet−/− hosts partially contribute to the decreased donor T cell proliferation. Furthermore, although T-bet on hematopoietic cells was required for GVHD development, it was largely dispensable for the graft-versus-leukemia effect. Taken together with our previous findings, we propose that T-bet is a potential therapeutic target for the control of GVHD through regulating donor T cells and recipient hematopoietic cells.
Mouse Cytomegalovirus Infection in BALB/c Mice Resembles Virus-Associated Secondary Hemophagocytic Lymphohistiocytosis and Shows a Pathogenesis Distinct from Primary Hemophagocytic Lymphohistiocytosis
Authors: Brisse Ellen , Imbrechts Maya , Put Karen , Avau Anneleen , Mitera Tania , Berghmans Nele , Rutgeerts Omer , Waer Mark , Ninivaggi Marisa , Kelchtermans Hilde , Boon Louis , Snoeck Robert , Wouters Carine H. , Andrei Graciela , Matthys Patrick
Published: February 2016

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening immunological disorder that is characterized by systemic inflammation, widespread organ damage, and hypercytokinemia. Primary HLH is caused by mutations in granule-mediated cytotoxicity, whereas secondary HLH occurs, without a known genetic background, in a context of infections, malignancies, or autoimmune and autoinflammatory disorders. Clinical manifestations of both HLH subtypes are often precipitated by a viral infection, predominantly with Herpesviridae. Exploiting this knowledge, we established an animal model of virus-associated secondary HLH by infecting immunocompetent wild-type mice with the β-herpesvirus murine CMV. C57BL/6 mice developed a mild inflammatory phenotype, whereas BALB/c mice displayed the clinicopathologic features of HLH, as set forth in the Histiocyte Society diagnostic guidelines: fever, cytopenia, hemophagocytosis, hyperferritinemia, and elevated serum levels of soluble CD25. BALB/c mice also developed lymphadenopathy, liver dysfunction, and decreased NK cell numbers. Lymphoid and myeloid cells were in a hyperactivated state. Nonetheless, depletion of CD8+ T cells could not inhibit or cure the HLH-like syndrome, highlighting a first dissimilarity from mouse models of primary HLH. Immune cell hyperactivation in BALB/c mice was accompanied by a cytokine storm. Notably, plasma levels of IFN-γ, a key pathogenic cytokine in models of primary HLH, were the highest. Nevertheless, murine CMV–infected IFN-γ–deficient mice still developed the aforementioned HLH-like symptoms. In fact, IFN-γ–deficient mice displayed a more complete spectrum of HLH, including splenomegaly, coagulopathy, and decreased NK cell cytotoxicity, indicating a regulatory role for IFN-γ in the pathogenesis of virus-associated secondary HLH as opposed to its central pathogenic role in primary HLH.
Cutting Edge: Engineering Active IKKβ in T Cells Drives Tumor Rejection
Authors: Evaristo César , Spranger Stefani , Barnes Sarah E. , Miller Michelle L. , Molinero Luciana L. , Locke Frederick L. , Gajewski Thomas F. , Alegre Maria-Luisa
Published: February 2016

Acquired dysfunction of tumor-reactive T cells is one mechanism by which tumors can evade the immune system. Identifying and correcting pathways that contribute to such dysfunction should enable novel anticancer therapy design. During cancer growth, T cells show reduced NF-κB activity, which is required for tumor rejection. Impaired T cell–intrinsic NF-κB may create a vicious cycle conducive to tumor progression and further T cell dysfunction. We hypothesized that forcing T cell–intrinsic NF-κB activation might break this cycle and induce tumor elimination. NF-κB was activated in T cells by inducing the expression of a constitutively active form of the upstream activator IκB kinase β (IKKβ). T cell–restricted constitutively active IKKβ augmented the frequency of functional tumor-specific CD8+ T cells and improved tumor control. Transfer of constitutively active IKKβ–transduced T cells also boosted endogenous T cell responses that controlled pre-established tumors. Our results demonstrate that driving T cell–intrinsic NF-κB can result in tumor control, thus identifying a pathway with potential clinical applicability.
Speciation of 127I and 129I in atmospheric aerosols at Risø, Denmark: insight into sources of iodine isotopes and their species transformations
Authors: Zhang Luyuan , Hou Xiaolin , Xu Sheng
Published: February 2016

Abstract. Speciation analysis of iodine in aerosols is a very useful approach for understanding geochemical cycling of iodine in the atmosphere. In this study, overall iodine species, including water-soluble iodine species (iodide, iodate and water-soluble organic iodine), NaOH-soluble iodine, and insoluble iodine have been determined for 129I and 127I in the aerosols collected at Risø, Denmark, during March and May 2011 (shortly after the Fukushima nuclear accident) and in December 2014. The measured concentrations of total iodine are in the range of 1.04–2.48 ng m−3 for 127I and (11.3–97.0)  ×  105 atoms m−3 for 129I, corresponding to 129I ∕ 127I atomic ratios of (17.8–86.8)  ×  10−8. The contribution of Fukushima-derived 129I (peak value of 6.3  ×  104 atoms m−3) is estimated to be negligible (less than 6 %) compared to the total 129I concentration in northern Europe. The concentrations and species of 129I and 127I in the aerosols are found to be strongly related to their sources and atmospheric pathways. Aerosols that were transported over the contaminated seas contained higher concentrations of 129I than aerosols transported over the European continent. The high 129I concentrations of the marine aerosols are attributed to secondary emission of marine discharged 129I in the contaminated seawater in the North Sea, North Atlantic Ocean, English Channel, Kattegat, etc., rather than direct gaseous release from the European nuclear reprocessing plants (NRPs). Water-soluble iodine was found to be a minor fraction to the total iodine for both 127I (7.8–13.7 %) and 129I (6.5–14.1 %) in ocean-derived aerosols, but accounted for 20.2–30.3 % for 127I and 25.6–29.5 % for 129I in land-derived aerosols. Iodide was the predominant form of water-soluble iodine, accounting for more than 97 % of the water-soluble iodine. NaOH-soluble iodine seems to be independent of the sources of aerosols. The significant proportion of 129I and 127I found in NaOH-soluble fractions is likely bound with organic substances. In contrast to water-soluble iodine, the sources of air masses exerted distinct influences on insoluble iodine for both 129I and 127I, with higher values for marine air masses and lower values for terrestrial air masses.
On the progress of the 2015–2016 El Niño event
Authors: Varotsos Costas A. , Tzanis Chris G. , Sarlis Nicholas V.
Published: February 2016

Abstract. It has been recently reported that the current 2015–2016 El Niño could become "one of the strongest on record". To further explore this claim, we performed the new analysis described in detail in Varotsos et al. (2015) that allows the detection of precursory signals of the strong El Niño events by using a recently developed non-linear dynamics tool. In this context, the analysis of the Southern Oscillation Index time series for the period 1876–2015 shows that the running 2015–2016 El Niño would be rather a "moderate to strong" or even a "strong" event and not “one of the strongest on record", as that of 1997–1998.
Volatility of organic aerosol and its components in the megacity of Paris
Authors: Paciga Andrea , Karnezi Eleni , Kostenidou Evangelia , Hildebrandt Lea , Psichoudaki Magda , Engelhart Gabriella J. , Lee Byong-Hyoek , Crippa Monica , Prévôt André S. H. , Baltensperger Urs , Pandis Spyros N.
Published: February 2016

Abstract. Using a mass transfer model and the volatility basis set, we estimate the volatility distribution for the organic aerosol (OA) components during summer and winter in Paris, France as part of the collaborative project MEGAPOLI. The concentrations of the OA components as a function of temperature were measured combining data from a thermodenuder and an aerosol mass spectrometer (AMS) with Positive Matrix Factorization (PMF) analysis. The hydrocarbon-like organic aerosol (HOA) had similar volatility distributions for the summer and winter campaigns with half of the material in the saturation concentration bin of 10 µg m−3 and another 35–40 % consisting of low and extremely low volatility organic compounds (LVOCs with effective saturation concentrations C* of 10−3–0.1 µg m−3 and ELVOCs C* less or equal than 10−4 µg m−3, respectively). The winter cooking OA (COA) was more than an order of magnitude less volatile than the summer COA. The low-volatility oxygenated OA (LV-OOA) factor detected in the summer had the lowest volatility of all the derived factors and consisted almost exclusively of ELVOCs. The volatility for the semi-volatile oxygenated OA (SV-OOA) was significantly higher than that of the LV-OOA, containing both semi-volatile organic components (SVOCs with C* in the 1–100 µg m−3 range) and LVOCs. The oxygenated OA (OOA) factor in winter consisted of SVOCs (45 %), LVOCs (25 %) and ELVOCs (30 %). The volatility of marine OA (MOA) was higher than that of the other factors containing around 60 % SVOCs. The biomass burning OA (BBOA) factor contained components with a wide range of volatilities with significant contributions from both SVOCs (50 %) and LVOCs (30 %). Finally, combining the bulk average O : C ratios and volatility distributions of the various factors, our results are placed into the two-dimensional volatility basis set (2D-VBS) framework. The OA factors cover a broad spectrum of volatilities with no direct link between the average volatility and average O : C of the OA components.
High-resolution ammonia emissions inventories in China from 1980 to 2012
Authors: Kang Yaning , Liu Mingxu , Song Yu , Huang Xin , Yao Huan , Cai Xuhui , Zhang Hongsheng , Kang Ling , Liu Xuejun , Yan Xiaoyuan , He Hong , Zhang Qiang , Shao Min , Zhu Tong
Published: February 2016

Abstract. Ammonia (NH3) can interact in the atmosphere with other trace chemical species, which can lead to detrimental environmental consequences, such as the formation of fine particulates and ultimately global climate change. China is a major agricultural country, and livestock numbers and nitrogen fertilizer use have increased drastically since 1978, following the rapid economic and industrial development experienced by the country. In this study, comprehensive NH3 emissions inventories were compiled for China for 1980–2012. In a previous study, we parameterized emissions factors (EFs) considering ambient temperature, soil acidity, and the method and rate of fertilizer application. In this study, we refined these EFs by adding the effects of wind speed and new data from field experiments of NH3 flux in cropland in northern China. We found that total NH3 emissions in China increased from 5.9 to 11.1 Tg from 1980 to 1996, and then decreased to 9.7 Tg in 2012. The two major contributors were livestock manure and synthetic fertilizer application, which contributed 80–90 % of the total emissions. Emissions from livestock manure rose from 2.86 Tg (1980) to 6.16 Tg (2005), and then decreased to 5.0 Tg (2012); beef cattle were the largest source followed by laying hens and pigs. The remarkable downward trend in livestock emissions that occurred in 2007 was attributed to a decrease in the numbers of various livestock animals, including beef cattle, goats, and sheep. Meanwhile, emissions from synthetic fertilizer ranged from 2.1 Tg (1980) to 4.7 Tg (1996), and then declined to 2.8 Tg (2012). Urea and ammonium bicarbonate (ABC) dominated this category of emissions, and a decline in ABC application led to the decrease in emissions that took place from the mid-1990s onwards. High emissions were concentrated in eastern and southwestern China. Seasonally, peak NH3 emissions occurred in spring and summer. The inventories had a monthly temporal resolution and a spatial resolution of 1000 m, and thus are suitable for global and regional air-quality modeling.
Characteristics of lower stratospheric transport as inferred from the age of air spectrum
Authors: Ploeger F. , Birner T.
Published: February 2016

Abstract. Trace gas transport in the lower stratosphere is investigated by analyzing seasonal and inter-annual variations of the age of air spectrum - the probability distribution of stratospheric transit times. Age spectra are obtained using the Lagrangian transport model CLaMS driven by ERA-Interim winds, and using a boundary-impulse-response method based on multiple tracer pulses. Seasonal age spectra show large deviations from an idealized stationary unimodal shape. Multiple modes emerge in the spectrum throughout the stratosphere, strongest at high latitudes, caused by the interplay of seasonally varying tropical upward mass flux, stratospheric transport barriers and recirculation. The annual mean spectrum, on the other hand, is found to be well described by an idealized stationary spectrum. Inter-annual variations in transport (e.g., QBO, ENSO) cause significant modulations of the age spectrum shape. In fact, one particular QBO phase may determine the spectrum's mode during the following 2–3 years. Interpretation of the age spectrum in terms of transport contributions due to the residual circulation and mixing is generally not straightforward. Advection by the residual circulation turns out to represent the dominant pathway in the deep tropics and in the winter hemisphere extratropics above 500 K, controlling the modal age in these regions. In contrast, in the summer hemisphere, particularly in the lowermost stratosphere, mixing represents the most probable pathway controlling the modal age. Analysis of the full age spectrum compared to mean age is highly beneficial for separating the effects of different transport processes, and is strongly recommended as a diagnostic for model inter-comparisons.
Tropospheric Ozone Seasonal and Long-term Variability as seen by lidar and surface measurements at the JPL-Table Mountain Facility, California
Authors: Granados-Muñoz Maria Jose , Leblanc Thierry
Published: February 2016

Abstract. A combined surface and tropospheric ozone climatology and interannual variability study was performed for the first time using co-located ozone photometer measurements (2013–2015) and tropospheric ozone differential absorption lidar measurements (2000–2015) at the Jet Propulsion Laboratory Table Mountain Facility (TMF, elev. 2285 m), in California. The surface time-series were investigated both in terms of seasonal and diurnal variability. The observed surface ozone is typical of high-elevation remote-sites, with small amplitude of the seasonal and diurnal cycles, and high ozone values, compared to neighboring lower altitude stations representative of urban boundary layer conditions. The ozone mixing ratio ranges from 45 ppbv in the winter morning hours to 65 ppbv in the spring and summer afternoon hours. At the time of the lidar measurements (early night), the seasonal cycle observed at the surface is similar to that observed by lidar between 3.5 km and 9 km. Above 9 km, the local tropopause height variation with time and season impacts significantly the ozone lidar observations. The frequent tropopause folds found in the vicinity of TMF (27 % of the time, mostly in winter and spring) produce a dual vertical structure in ozone within the fold layer, characterized by higher-than-average values in the bottom half of the fold (12–14 km), and lower-than-averaged values in the top half of the fold (14–18 km). This structure is consistent with the expected origin of the air parcels within the fold, i.e., mid-latitude stratospheric air folding down below the upper tropospheric sub-tropical air. No significant signature of interannual variability could be observed on the 2000–2015 deseasonalized lidar time-series, with only a statistically non-significant positive anomaly during the years 2003–2007. Our trend analysis reveals however a statistically significant positive trend of 0.31 ppbv.year-1 in the free troposphere for the period 2000–2015. A classification of the air parcels sampled by lidar was made at 1-km interval between 5 km and 14 km altitude, using 8-days backward trajectories (HYSPLIT). Our classification revealed the large influence of the Pacific Ocean, with air parcels of low ozone content (50–65 ppbv), and significant influence of the stratosphere leading to ozone values of 65–80 ppbv down to 8–9 km. In summer, enhanced ozone values (70 ppbv) were found in air parcels originating from Central America, probably owed to the enhanced thunderstorm activity during the North American Monsoon. No outstanding influence from Asia was identified.
A total sky cloud detection method using real clear sky background
Authors: Yang Jun , Min Qilong , Lu Weitao , Ma Ying , Yao Wen , Lu Tianshu , Du Juan , Liu Guangyi
Published: February 2016

Abstract. The brightness distribution of sky background is usually non-uniform, which creates many problems for traditional cloud detection methods, including the failure of thin cloud detection in total sky images and significantly reducing retrieval accuracy in the circumsolar and near-horizon regions. This paper describes the development of a new cloud detection algorithm, named "clear sky background differencing (CSBD)", which is accomplished by differencing the original image and the corresponding clear sky background image using the images' green channel. First, a library of clear sky background images with a variety of solar elevation angles needs to be developed. The image rotation and image brightness adjustment algorithms are applied to ensure the two images being differenced have the same solar position and similar brightness distribution. Sensitivity tests show that the cloud detection results are satisfactory when the two images have the same solar positions. Several experimental cases show that the CSBD algorithm obtains good cloud recognition results visually, especially for thin clouds.
Intense air-sea exchange and heavy rainfall: impact of the northern Adriatic SST
Authors: Stocchi P. , Davolio S.
Published: February 2016

Abstract. Over the northern Adriatic basin, intense air-sea interactions are often associated with heavy precipitation over the mountainous areas surrounding the basin. In this study, a high-resolution mesoscale model is employed to simulate three severe weather events and to evaluate the effect of the sea surface temperature on the intensity and location of heavy rainfall. The sensitivity tests show that the impact of SST varies among the events and it mainly involves the modification of the PBL characteristics and thus the flow dynamics and its interaction with the orography.
Challenges in modeling spatiotemporally varying phytoplankton blooms in the Northwestern Arabian Sea and Gulf of Oman
Authors: Sedigh Marvasti S. , Gnanadesikan A. , Bidokhti A. A. , Dunne J. P. , Ghader S.
Published: February 2016

Abstract. Recent years have shown an increase in harmful algal blooms in the Northwest Arabian Sea and Gulf of Oman, raising the question of whether climate change will accelerate this trend. This has led us to examine whether the Earth System Models used to simulate phytoplankton productivity accurately capture bloom dynamics in this region – both in terms of the annual cycle and interannual variability. Satellite data (SeaWIFS ocean color) show two climatological blooms in this region, a wintertime bloom peaking in February and a summertime bloom peaking in September. On a regional scale, interannual variability of the wintertime bloom is dominated by cyclonic eddies which vary in location from one year to another. Two coarse (1°) models with the relatively complex biogeochemistry (TOPAZ) capture the annual cycle but neither eddies nor the interannual variability. An eddy-resolving model (GFDL CM2.6) with a simpler biogeochemistry (miniBLING) displays larger interannual variability, but overestimates the wintertime bloom and captures eddy-bloom coupling in the south but not in the north. The models fail to capture both the magnitude of the wintertime bloom and its modulation by eddies in part because of their failure to capture the observed sharp thermocline and/or nutricline in this region. When CM2.6 is able to capture such features in the Southern part of the basin, eddies modulate diffusive nutrient supply to the surface (a mechanism not previously emphasized in the literature). For the model to simulate the observed wintertime blooms within cyclones, it will be necessary to represent this relatively unusual nutrient structure as well as the cyclonic eddies. This is a challenge in the Northern Arabian Sea as it requires capturing the details of the outflow from the Persian Gulf – something that is poorly done in global models.
Transient Earth system responses to cumulative carbon dioxide emissions: linearities, uncertainties, and probabilities in an observation-constrained model ensemble
Authors: Steinacher M. , Joos F.
Published: February 2016

Abstract. Information on the relationship between cumulative fossil CO2 emissions and multiple climate targets is essential to design emission mitigation and climate adaptation strategies. In this study, the transient response of a climate or environmental variable per trillion tonnes of CO2 emissions, termed TRE, is quantified for a set of impact-relevant climate variables and from a large set of multi-forcing scenarios extended to year 2300 towards stabilization. An  ∼ 1000-member ensemble of the Bern3D-LPJ carbon–climate model is applied and model outcomes are constrained by 26 physical and biogeochemical observational data sets in a Bayesian, Monte Carlo-type framework. Uncertainties in TRE estimates include both scenario uncertainty and model response uncertainty. Cumulative fossil emissions of 1000 Gt C result in a global mean surface air temperature change of 1.9 °C (68 % confidence interval (c.i.): 1.3 to 2.7 °C), a decrease in surface ocean pH of 0.19 (0.18 to 0.22), and a steric sea level rise of 20 cm (13 to 27 cm until 2300). Linearity between cumulative emissions and transient response is high for pH and reasonably high for surface air and sea surface temperatures, but less pronounced for changes in Atlantic meridional overturning, Southern Ocean and tropical surface water saturation with respect to biogenic structures of calcium carbonate, and carbon stocks in soils. The constrained model ensemble is also applied to determine the response to a pulse-like emission and in idealized CO2-only simulations. The transient climate response is constrained, primarily by long-term ocean heat observations, to 1.7 °C (68 % c.i.: 1.3 to 2.2 °C) and the equilibrium climate sensitivity to 2.9 °C (2.0 to 4.2 °C). This is consistent with results by CMIP5 models but inconsistent with recent studies that relied on short-term air temperature data affected by natural climate variability.
Biogeochemical and biological impacts of diazotroph blooms in a Low Nutrient Low Chlorophyll ecosystem: synthesis from the VAHINE mesocosm experiment (New Caledonia)
Authors: Bonnet Sophie , Baklouti Melika , Gimenez Audrey , Berthelot Hugo , Berman-Frank Ilana
Published: February 2016

Abstract. In marine ecosystems, N2 fixation provides the predominant external source of nitrogen (N) (140 ± 50 Tg N yr−1), contributing more than atmospheric and riverine inputs to the N supply. Yet the fate and magnitude of the newly-fixed N, or diazotroph-derived N (hereafter named DDN) in marine ecosystems is poorly understood. Moreover, it remains unclear whether the DDN is preferentially directly exported out of the photic zone, recycled by the microbial loop, and/or transferred into larger organisms, subsequently enhancing indirect particle export. These questions were investigated in the framework of the VAHINE (VAriability of vertical and tropHIc transfer of diazotroph derived N in the south wEst Pacific) project. Triplicate large volume (~50 m3) mesocosms were deployed in the tropical South West Pacific coastal ocean (New Caledonia) to maintain a stable water-mass without disturbing ambient light and temperature conditions. The mesocosms were intentionally fertilized with ~0.8 μM dissolved inorganic phosphorus (DIP) at the start of the experiment to stimulate diazotrophy. A total of 47 stocks, fluxes, enzymatic activities and diversity parameters were measured daily inside and outside the mesocosms by the 40 scientists involved in the project. The experiment lasted for 23 days and was characterized by two distinct and successive diazotroph blooms: a dominance of diatom-diazotroph associations (DDAs) during the first half of the experiment (days 2–14) followed by a bloom of UCYN-C during the second half of the experiment (days 15–23). These conditions provided a unique opportunity to compare the DDN transfer and export efficiency associated with different diazotrophs. Here we summarize the major experimental and modelling results obtained during the project and described in the VAHINE Special issue, in particular those regarding the evolution of the main standing stocks, fluxes and biological characteristics over the 23-days experiment, the contribution of N2 fixation to export fluxes, the DDN released to dissolved pool and its transfer to the planktonic food web (bacteria, phytoplankton, zooplankton). We then apply our Eco3M modelling platform further to infer the fate of DDN in the ecosystem and role of N2 fixation on productivity, food web structure and carbon export. Recommendations for future work are finally provided in the conclusion section.
No tropospheric ozone impact on the carbon uptake by a Belgian pine forest
Authors: Verryckt Lore , Op de Beeck Maarten , Neirynck Johan , Gielen Bert , Roland Marilyn , Janssens Ivan A.
Published: February 2016

Abstract. High stomatal ozone (O3) uptake has been shown to negatively affect crop yields and the growth of tree seedlings. However, little is known about the effect of O3 on the carbon uptake by mature forest trees. This study investigated the effect of high O3 events on gross primary production (GPP) for a Scots pine stand near Antwerp, Belgium over the period 1998–2013. Stomatal O3 fluxes were modelled using in situ O3 concentration measurements and a multiplicative stomatal model, which was parameterised and validated for this Scots pine stand. Ozone-induced GPP reduction is most likely to occur during or shortly after days with high stomatal O3 uptake. Therefore, a GPP model parameterised for days with low stomatal O3 uptake rates was used to simulate GPP during periods of high stomatal O3 uptake. Eventual negative effects of high stomatal O3 uptake on GPP would then result in an overestimation of GPP by the model during or after high stomatal O3 uptake events. The O3 effects on GPP were linked to AOT40 and PODy. Although the critical levels for both indices were exceeded in every single year, no significant negative effects were found of ozone on GPP and no correlations between GPP residuals and AOT40 and PODy were found. Overall, we conclude that no O3 effects were detected on the carbon uptake by this Scots pine stand.
Geochronological database and classification system for age uncertainties in Neotropical pollen records
Authors: Flantua S. G. A. , Blaauw M. , Hooghiemstra H.
Published: February 2016

Abstract. The newly updated inventory of palaeoecological research in Latin America offers an important overview of sites available for multi-proxy and multi-site purposes. From the collected literature supporting this inventory, we collected all available age model metadata to create a chronological database of 5116 control points (e.g. 14C, tephra, fission track, OSL, 210Pb) from 1097 pollen records. Based on this literature review, we present a summary of chronological dating and reporting in the Neotropics. Difficulties and recommendations for chronology reporting are discussed. Furthermore, for 234 pollen records in northwest South America, a classification system for age uncertainties is implemented based on chronologies generated with updated calibration curves. With these outcomes age models are produced for those sites without an existing chronology, alternative age models are provided for researchers interested in comparing the effects of different calibration curves and age–depth modelling software, and the importance of uncertainty assessments of chronologies is highlighted. Sample resolution and temporal uncertainty of ages are discussed for different time windows, focusing on events relevant for research on centennial- to millennial-scale climate variability. All age models and developed R scripts are publicly available through figshare, including a manual to use the scripts.
Potential impact of climate and socioeconomic changes on future agricultural land use in West Africa
Authors: Ahmed Kazi Farzan , Wang Guiling , You Liangzhi , Yu Miao
Published: February 2016

Abstract. Agriculture is a key component of anthropogenic land use and land cover changes that influence regional climate. Meanwhile, in addition to socioeconomic drivers, climate is another important factor shaping agricultural land use. In this study, we compare the contributions of climate change and socioeconomic development to potential future changes of agricultural land use in West Africa using a prototype land use projection (LandPro) algorithm. The algorithm is based on a balance between food supply and demand, and accounts for the impact of socioeconomic drivers on the demand side and the impact of climate-induced crop yield changes on the supply side. The impact of human decision-making on land use is explicitly considered through multiple "what-if" scenarios. In the application to West Africa, future crop yield changes were simulated by a process-based crop model driven with future climate projections from a regional climate model, and future changes of food demand is projected using a model for policy analysis of agricultural commodities and trade. Without agricultural intensification, the climate-induced decrease in crop yield together with future increases in food demand is found to cause a significant increase in cropland areas at the expense of forest and grassland by the mid-century. The increase in agricultural land use is primarily climate-driven in the western part of West Africa and socioeconomically driven in the eastern part. Analysis of results from multiple scenarios of crop area allocation suggests that human adaptation characterized by science-informed decision-making can potentially minimize future land use changes in many parts of the region.
Raumverträglicher Ausbau von erneuerbaren Energien – ein alternativer Standortplanungsansatz für eine nachhaltige Energiewende
Authors: Bosch Stephan , Rathmann Joachim , Simetsreiter Florian
Published: February 2016

Abstract. By now, there are numerous high-quality studies discussing the incompatibility of the development of renewable energies with the preservation of landscape. However, no further insight is provided as to how a holistic spatial integration of renewable energies may be achieved. Yet the ambitious aim of Germany's government of increasing the percentage of energy obtained from renewable energies to 45 % by 2025 and to 60 % by 2035 will lead to an even greater spatial strain on Germany's rural areas as it has been the case so far. Therefore, this study aims to critically investigate the currently established paradigm of site planning for renewable energies using GIS analysis. Based upon the findings, an alternative, holistic concept of site planning will be developed and exemplified.
Joint State and Parameter Estimation of Two Land Surface Models Using the Ensemble Kalman Filter and Particle Filter
Authors: Zhang Hongjuan , Hendricks Franssen Harrie-Jan , Han Xujun , Vrugt Jasper , Vereecken Harry
Published: February 2016

Abstract. Land surface models (LSMs) contain a suite of different parameters and state variables to resolve the water and energy balance at the soil-atmosphere interface. Many of the parameters of these models cannot be measured directly in the field, and require calibration against flux and soil moisture data. In this paper, we use the Variable Infiltration Capacity Hydrologic Model (VIC) and the Community Land Model (CLM) to simulate temporal variations in soil moisture content at 5, 20 and 50 cm depth in the Rollesbroich experimental watershed in Germany. Four different data assimilation (DA) methods are used to jointly estimate the spatially distributed water content values, and hydraulic and/or thermal properties of the resolved soil domain. This includes the Ensemble Kalman Filter (EnKF) using state augmentation or dual estimation, the Residual Resampling Particle Filter (RRPF) and Markov chain Monte Carlo Particle Filter (MCMCPF). These four DA methods are tuned and calibrated for a five month data period, and subsequently evaluated for another five month period. Our results show that all the different DA methods improve the fit of the VIC and CLM model to the observed water content data, particularly if the maximum baseflow velocity (VIC), soil hydraulic (VIC) properties and/or soil texture (CLM) are jointly estimated along with the model states. In the evaluation period, the augmentation and dual estimation method performed slightly better than RRPF and MCMCPF. The differences in simulated soil moisture values between the CLM and VIC model were larger than variations among the data assimilation algorithms. The best performance for the Rollesbroich site was observed for the CLM model. The strong underestimation of the soil moisture values of the third VIC-layer are likely explained by an inadequate parameterization of groundwater drainage.
Nature-Based Physical Activity Advertising: Recommendations Based on Attention Restoration Theory and Psychoevolutionary Theory
Authors: Gavarkovs Adam G
Published: February 2016

Recent research has suggested that physical activity in natural areas may provide benefits that exceed those in other settings. Additional benefits include increased self-esteem and enjoyment of the activity, and decreased negative mood states and blood pressure. Therefore, encouraging nature-based physical activities may play an important role in the promotion of health and wellness. Advertising has been cited as an important component of a health promotion campaign; although to date no study has recommended strategies for designing advertising specific to nature-based physical activities. The purpose of this article is to review two prominent human-nature interaction frameworks, Attention Restoration Theory (ART) and Psychoevolutionary Theory (PET), and based on their tenets, recommend strategies for message design. The two recommendations proposed are: (1) to include natural images that meet the restorative criteria outlined in both theories; and (2) to explicitly feature the additional benefits of exercising in natural spaces in advertisements. Adhering to these recommendations in the advertisement design process may increase the effectiveness of the message.