bluuebunny/crossref_metadata_2025 huggingface dataset:
Are podoplanin and ezrin involved in the invasion process of the ameloblastomas?
Authors: Costa Y.F. , Tjioe K.C. , Nonogaki S. , Soares F.A. , Pereira Lauris J.R. , Tostes Oliveira D.
Published: March 2015

The association between podoplanin and ezrin in the process of odontogenic tumors invasion has been suggested, but was not studied yet. Our purpose was to investigate the relationship between podoplanin and ezrin expressions in the odontogenic epithelium of ameloblastomas. Forty-seven ameloblastomas were analyzed by immunohistochemistry using anti-podoplanin and anti-ezrin antibodies. The expressions of both proteins were evaluated using a score method and the comparison and association between these proteins were verified, respectively, by Wilcoxon Signed-Rank test and by Spearmanâ€™s rank correlation coefficient, using a statistical significance level of 0.05. The majority of tumors (87.2%) exhibited strong membranous expression of podoplanin in the peripheral cells. Cytoplasmic expression of ezrin in the peripheral cells of ameloblastomas was stronger than its membranous expression. No statistically significant correlation was observed between podoplanin and ezrin. However, there was statistically significant difference between membranous podoplanin and membranous ezrin expressions, between cytoplasmic podoplanin and membranous ezrin expressions, and between cytoplasmic podoplanin and cytoplasmic ezrin expressions. There was no statistical difference between membranous podoplanin and cytoplasmic ezrin expressions. These results suggest a synergistic role of both proteins in the process of invasion of ameloblastomas.
Genetica Humana
Authors: Redi CarloAlberto
Published: March 2015

Sometimes we do not realize that Spanish speaking people are one of the major linguistic group on our planet! Thus we have to welcome this excellent book devoted to, as the title clearly tell us, human genetics for the pleasure of the Spanish speaking people. Those who love genetics, young fellows at the beginning of their careers, esteemed professors and historians of science will get for the affordable price.....
Lumbar Sympathicolysis in Patients with Severe Peripheral Artery Disease: Hemodynamics of the Lower Limbs Determined by Near-Infrared Spectroscopy, Color Coded Duplex Sonography, and Temperature Measurement
Authors: Bombor Ingmar , Wissgott Christian , Andresen Reimer
Published: March 2015

The objective was to investigate the effects of CT-guided lumbar sympathicolysis on somatic regional oxygen saturation, arterial flow velocity, and skin temperature of the lower limbs in patients with advanced peripheral artery disease (PAD). CT-guided lumbar sympathicolysis was additionally performed after successful revascularization therapy in 61 patients with PAD in categories 5 and 6 according to Rutherford. Somatic regional oxygen saturation in the distal lower limbs was determined semiquantitatively with a near-infrared spectroscopy (NIRS) system. Before and after intervention, peak flow and end-diastolic flow velocity in the dorsalis pedis artery were determined by means of color-coded duplex sonography, and the skin temperature of the feet was measured with an infrared thermometer. After CT-guided lumbar sympathicolysis, somatic regional oxygen saturation, peak flow, end-diastolic flow velocity, and skin temperature in the lower limbs increased significantly.
Concurrent supplementation of arginine and antioxidant vitamins E and C reduces oxidative stress in broiler chickens after a challenge withEimeriaspp.
Authors: Dominguez P. A. , Pro-Martinez A. , Narciso-Gaytán C. , Hernández-Cázares A. , Sosa-Montes E. , Perez-Hernandez P. , Caldwell D. , Ruiz-Feria C. A.
Published: March 2015

Dominguez P.A., Pro-Martinez, A., Narciso-Gaytán, C., Hernández-Cázares, A., Sosa-Montes, E., Perez-Hernandez, P., Caldwell, D. and Ruiz-Feria, C. A. 2015. Concurrent supplementation of arginine and antioxidant vitamins E and C reduces oxidative stress in broiler chickens after a challenge with Eimeria spp. Can. J. Anim. Sci. 95: 143–153. Oxidation is a major problem associated with pathogen damage in animals. One-day-old mixed-sex broiler chicks (Cobb 500; n=624) were randomly assigned to one of six treatments: a basal diet [CTL; 40 mg of vitamin E (VE) kg−1of feed and 1.5% Arginine (Arg)] or the basal diet plus Arg (ARG; 0.3%), Arg+VE (AVE; 0.3% and 40 mg kg−1respectively), Arg+vitamin C (VC) (AVC; 0.3% and 1 g kg−1respectively), VE+VC (VEC; 40 mg+1 g kg−1respectively), or Arg+VE+VC (AVEC; 0.3%+40 mg+1 g kg−1respectively). At day 14, all birds were orally challenged with 100× the normal dose of Advent®coccidiosis vaccine (450 000 oocysts). Intestinal lesion scores (LS) in duodenum, jejunum and ceca were recorded, along with relative immune system organ weights at day 23. Plasma samples were taken before (2 h) and after challenge (12, 24 and 48 h) to determine malondialdehyde (MDA), nitric oxide (NO) and glutathione peroxidase activity (GPx). Birds fed the VEC diet were heavier at 7 d (P<0.05) than birds fed the AVE diet. CTL birds had heavier (P<0.05) bursas than AVC birds; no differences among treatments for spleen and thymus were found. The jejunum LS was lower in the AVC and VEC birds than in CTL birds, whereas ceca LS was highest in AVE birds, and the duodenum LS was not affected by treatment. Birds fed the AVEC diet had the lowest MDA levels before challenge, but higher levels of MDA than birds fed the CTL, ARG or AVE 12 h after challenge. Before challenge ARG birds had higher (P<0.05) NO levels than AVEC-fed birds, but 12 h after challenge birds fed the CTL, ARG or AVE diet had lower NO levels than birds fed the AVC, VEC or AVEC diet. Before challenge AVEC-fed birds had higher (P<0.001) GPx activity than CTL, ARG and AVE birds, but after 12, 24 and 48 h VEC birds showed higher GPx activity than CTL, ARG- and AVE-fed birds. Although Arg, VE and VC, modulated oxidative stress during coccidiosis challenge, the effects were not sufficient to affect performance relative to the control diet.
Effects of forage silage species on yearling growth performance, carcass and meat quality, and nutrient composition in a forage based beef production system
Authors: Berthiaume R. , Lafrenière C. , Girard C. , Campbell C. P. , Pivotto L. M. , Mandell I. B.
Published: March 2015

Berthiaume, R., Lafrenière, C., Girard, C., Campbell, C. P., Pivotto, L. M. and Mandell, I. B. 2015. Effects of forage silage species on yearling growth performance, carcass and meat quality, and nutrient composition in a forage based beef production system. Can. J. Anim. Sci. 95: 173–187. Forty weaned, crossbred beef calves (predominantly Angus and Simmental) were forage-finished using all-silage diets (red clover–timothy versus tall fescue) to examine forage species’ effects on growth performance, carcass traits, meat quality, and nutrient composition. Weaned calves (257 d of age) were forage-finished using red clover–timothy or tall fescue silage and harvested at approximately 1 yr of age. During carcass processing, one side from each carcass was covered with a polyliner to examine if reducing rates of chilling could compensate for limited fat cover expected from low dietary energy contents fed, and limited time on feed. Longissimus thoracis, semimembranosus, and semitendinosus steaks were aged 10, 14, and 21 d to examine effects on Warner–Bratzler shear force values while fatty acid and vitamin B12 composition were determined on 10-d-aged steaks. Average daily gain, feed efficiency, hot carcass weights, and longissimus muscle area were greater (P<0.03) when cattle were fed red clover–timothy versus tall fescue silage, most likely due to the higher protein content of red clover–timothy silage. Shear force was greater (P<0.002) in steaks from all muscles evaluated from cattle fed tall fescue versus red clover–timothy silage. In comparison to 10-d-aged steaks, 14 d of ageing were needed to reduce (P<0.001) shear force for longissimus steaks, while 21 d of ageing were needed to reduce (P<0.001) shear force for semitendinosus steaks. Use of a polyliner decreased (P=0.0001) the rate of temperature decline at selected carcass sites, but did not reduce shear force values. The percent of n-3 fatty acids and polyunsaturated fatty acid/saturated fatty acid ratio were greater (P<0.04) in longissimus from cattle fed red clover–timothy versus feeding tall fescue silage. Feeding red clover–timothy silage improved growth performance, carcass, shear force, and fatty acid composition traits versus feeding tall fescue silage.
Effect of feeding strategically blended feed pellets on rumen fermentation and nutrient digestion
Authors: Zenobi M. G. , Lardner H. A. , Jefferson P. G. , McKinnon J. J.
Published: March 2015

Zenobi, M. G., Lardner, H. A., Jefferson, P. G. and McKinnon, J. J. 2015. Effect of feeding strategically blended feed pellets on rumen fermentation and nutrient digestion. Can. J. Anim. Sci. 95: 243–254. Five rumen-cannulated heifers (631±31 kg) were used in a 5×5 Latin square design to evaluate the effect of feeding blended by-product feed pellets (BP) on rumen fermentation and nutrient utilization. Four BP were formulated to be high in starch (HS) or fat (HF) and either low (LSP) or high (HSP) in soluble crude protein. The control diet consisted of 49.1% forage and 50.9% barley-based concentrate. Treatments were 50.3% forage and 49.7% BP (DM). Heifers fed HF BP had higher (P=0.05) mean pH values than those fed the control diet and tended (P=0.07) to have higher mean pH than those fed the HS BP. Feeding HF BP decreased (P<0.05) rumen propionate concentration without affecting acetate or total volatile fatty acid concentration. Rumen ammonia-nitrogen (N) levels and digestibility of crude protein was highest (P<0.05) for HS, intermediate for HF, and the lowest for the control. Feeding HF BP reduced (P<0.05) gross energy digestibility and digestible energy content relative to both the control and HS diets while both BP increased (P<0.01) their extract digestibility compared with the control. There was minimal effect of pellet soluble crude protein content. Total N excretion (% of N intake) was not affected (P>0.05) by treatment. These results indicate that BP had no adverse effects on rumen fermentation or apparent nutrient digestibility and did not result in issues with excess nutrient excretion. As such BP can be used as an alternative energy source in backgrounding diets to cereal grains and can help counteract volatility in feed grain prices.
Agrobacterium-mediated genetic transformation of peanut and the efficient recovery of transgenic plants
Authors: Chen Mingna , Yang Qingli , Wang Tong , Chen Na , Pan Lijuan , Chi Xiaoyuan , Yang Zhen , Wang Mian , Yu Shanlin
Published: March 2015

Chen, M., Yang, Q., Wang, T., Chen, N., Pan, L., Chi, X., Yang, Z., Wang, M., and Yu, S. 2015. Agrobacterium-mediated genetic transformation of peanut and the efficient recovery of transgenic plants. Can. J. Plant Sci. 95: 735–744. Four genotypes of peanut and two sources of explants (cotyledon and mesocotyl) were tested for their susceptibility to genetic transformation by the Agrobacterium tumefaciens strain LBA4404 that harbored the binary vector pCAMBIA1301. This plasmid contains the hygromycin phosphotransferase (hpt) and β-glucuronidase (GUS) genes, each under the control of a CaMV35S promoter. Comparative analyses of regeneration and transformation efficiencies indicated that mesocotyl was a better target tissue than cotyledon, and peanut genotypes of that mature early and have relatively small seeds (such as Huayu 26 and Huayu 20) were shown to be comparatively responsive to transformation. Sonication of explants soaked with solutions containing Agrobacterium was shown to optimize transformation. Culture of explants on medium supplemented with 3 mg L−1 indole-3-butyric acid and 0.1 mg L−1 napthaleneacetic acid enabled vigorous rooting from almost all transgenic shoots. More than 85% of the transplanted plants could produce morphologically normal flowers and pods with viable seeds. Phenotypic and genotypic monitoring of the inheritance of hpt and GUS genes through two generations indicated the expected 3:1 inheritance. Our results make Agrobacterium-mediated transformation a viable and useful tool for both breeding and functional genomic analysis of peanut.
The effect of weeds on soil arbuscular mycorrhizal fungi and agronomic traits in spring wheat (Triticum aestivumL.) under organic management in Canada
Authors: Kubota Hiroshi , Quideau Sylvie A. , Hucl Pierre J. , Spaner Dean M.
Published: March 2015

Kubota, H., Quideau, S. A., Hucl, P. J. and Spaner, D. M. 2015. The effect of weeds on soil arbuscular mycorrhizal fungi and agronomic traits in spring wheat (Triticum aestivum L.) under organic management in Canada. Can. J. Plant Sci. 95: 615–627. Understanding the influence of weeds in agroecosystems may aid in developing efficient and sustainable organic wheat production systems. We examined the effect of weeds on soil microbial communities and the performance of spring wheat (Triticum aestivum L.) under organic management in Edmonton, AB, Canada. We grew 13 Canadian spring wheat cultivars in organically managed hand-weeded less-weedy and weedy treatments in 2010 and 2011. The less-weedy treatment exhibited greater grain yield and tillers per square meter, while kernel weight, test weight, days to maturity, plant height, grain P and protein content were not altered by weed treatment. Canada Western Red Spring (CWRS) wheat cultivars CDC Go and CDC Kernen were the most yield-stable because they minimized fertile tiller reduction in response to weed pressure (10 and 13% reduction, respectively, compared with the average reduction of 20%). Other cultivars exhibited yield stability through increased kernel weight. The contribution of arbuscular mycorrhizal fungi (AMF) to the total phospholipid fatty acid increased in both treatments; however, the rate of this increase was greater in the weedy treatment than the less-weedy treatment (from 2.9 to 3.9%, from 2.8 to 3.1%, respectively). Weed dry biomass was positively correlated with AMF% in the less-weedy treatment only. Organic systems tend to be weedier than conventional systems. We found that weeds are important determinants of AMF proliferation in soil. In addition, choosing wheat cultivars that maintain important yield components under severe weed stress is one strategy to maximize yields in organic systems.
Simulating forage crop production in a northern climate with the Integrated Farm System Model
Authors: Jégo Guillaume , Rotz C. Alan , Bélanger Gilles , Tremblay Gaëtan F. , Charbonneau Édith , Pellerin Doris
Published: March 2015

Jégo, G., Rotz, C. A., Bélanger, G., Tremblay, G. F., Charbonneau, E. and Pellerin, D. 2015. Simulating forage crop production in a northern climate with the Integrated Farm System Model. Can. J. Plant Sci. 95: 745–757. Whole-farm simulation models are useful tools for evaluating the effect of management practices and climate variability on the agro-environmental and economic performance of farms. A few process-based farm-scale models have been developed, but none has been evaluated in northern regions with boreal and hemiboreal climates characterized by a short growing season and a long period with snow cover. The study objectives were to calibrate the grass sub-model of the Integrated Farm System Model (IFSM) and evaluate its predictions of yield and nutritive value of timothy and alfalfa, grown alone or in a mixture, using experimental field data from across Canada, andto assess IFSM's predictions of yield of major annual crops grown on dairy farms in eastern Canada using regional yield data from two contrasting regions. Several timothy and alfalfa datasets combining sites, years, harvests, and N fertilization rates were used to calibrate and evaluate the model. For timothy and alfalfa, the model's accuracy was globally satisfactory in predicting dry matter yield and neutral detergent fiber concentration with a normalized root mean square error (NRMSE)<30%. For N uptake, the scatter was a bit larger, especially for timothy (NRMSE= 49%), mainly because of a small range in the measured data. The model's accuracy for predicting the yield of annual crops was generally good, with an NRMSE<30%. Adding timothy and alfalfa to the grass sub-model of IFSM and verifying the model's performance for annual crops confirmed that IFSM can be used in northern regions of North America. In addition, the model was able to simulate the yield and nutritive value of a timothy–alfalfa mixture, which is the most common perennial mixture used in Canada.
Long-term response of forest plantation productivity and soils to a single application of municipal biosolids
Authors: Ouimet Rock , Pion Anne-Pascale , Hébert Marc
Published: March 2015

Ouimet, R., Pion, A.-P. and Hébert, M. 2015. Long-term response of forest plantation productivity and soils to a single application of municipal biosolids. Can. J. Soil Sci. 95: 187–199. After 16 to 19 yr, we revisited four experimental trials set up in the early 1990s to evaluate the long-term impact of municipal biosolids applied in forest plantations. Tree growth and the soil were sampled to determine the effects of a single application of biosolids applied at (liquid equivalent) rates of 0, 130, 200, and 400 m3ha−1. Tree radial growth responded markedly to biosolids in the young plantations, increasing from 18 % for Pinus resinosa to 62 % for Picea glauca, and up to 700 % for Quercus sp. Increases in phosphorus (P) concentrations in the tree foliage in response to biosolids could still be detected in the conifer trials. In the top 0–5 cm soil layer, organic carbon (C), total nitrogen (N), P, and copper (Cu) concentrations and pools increased, while soil compaction and bulk density decreased. In the deepest soil layer sampled (20–40 cm depth), the total N and calcium (Ca) pools were reduced by the biosolids treatments, while the pool of exchangeable acidity increased. Our observations indicate that a single application of liquid biosolids up to 400 m3ha−1(30 t ha−1DM) in young forest plantations is a sustainable practice without undue risk to such podzolic soils.
Equivalent latitude for prediction of soil development in a complex mapunit
Authors: Whitson Ivan R.
Published: March 2015

Whitson, I. R. 2015. Equivalent latitude for prediction of soil development in a complex mapunit. Can. J. Soil Sci. 95: 125–137. Soil pattern in the Hillwash complex mapunit from Saskatchewan is too variable to be resolved spatially with conventional mapping approaches. The equivalent latitude metric allows identification of an index based on gradient and aspect that ranks sites based on differences in direct radiant energy inputs. Effects on soil development with reference to surface horizon color and soil classification were investigated at three study areas in southern Saskatchewan. At the first, sites with equivalent latitude greater than local latitude (north group) had a higher frequency of darker soil colors than sites where equivalent latitude was less than local latitude (south group). Black Chernozemic profiles made up nine of 13 profiles from the north group compared with none in the south group or in local controls. Similar color and classification trends in a north sample group were found at a second study area. Results from a third study area more than 200 km away and in a drier ecoregion found similar differences albeit a different set of subgroups between north and south group soils at that location. The equivalent latitude metric could be used in a GIS context to better resolve soil characteristics within this complex mapunit, but only after additional work to include a climate parameter such as potential transpiration into the model.
Role of morphological structure and layering ofSphagnumandTomenthypnummosses on moss productivity and evaporation rates
Authors: Goetz Jonathan D. , Price Jonathan S.
Published: March 2015

Goetz, J. D. and Price, J. S. 2015. Role of morphological structure and layering of Sphagnum and Tomenthypnum mosses on moss productivity and evaporation rates. Can. J. Soil Sci. 95: 109–124. Morphological structures of peatland mosses control moss water relations and the rate of water loss by drainage and evaporation, thus influencing their physiological functions. While many of these mechanisms are understood for Sphagnum mosses, there is a limited understanding of how these processes operate in Tomenthypnum nitens, a dominant brown moss species in northern rich fens. This study contrasts how different hydrophysical characteristics of Tomenthypnum and Sphagnum species affect capillary water flow that supports evaporation and productivity. Laboratory investigations indicate that volumetric water content (θ), gross ecosystem productivity, and evaporation decreased with water table depth for both mosses, with Sphagnum capitula retaining 10–20% more water (θ range of 0.18–0.32 cm3cm−3) than Tomenthypnum (0.07−0.16 cm3cm−3). Despite lower θ and a smaller fraction of pores between 66 and 661 µm to retain water within the Tomenthypnum structure (10%) compared with Sphagnum (27%), both mosses had similar fractions of water conducting pore spaces and were able to maintain capillary rise throughout the experiment. While there was a larger difference in the bulk density and porosity of the Tomenthypnum moss compared with its underlying peat than there was in the Sphagnum profile, a layer of partially decomposed moss of intermediate properties was sufficient to provide a connection between the moss and peat under low water table conditions. In trying to characterize the soil-water pressure (ψ) in near-surface mosses of Tomenthypnum based on measurements of vapour pressure, we found disequilibrium conditions that severely underestimated ψ (i.e., very large negative pressures). It is this disequilibrium that drives evaporation and draws up capillary water to the moss surface for peatland–atmosphere carbon and water transfers.
Vector bundles on plane cubic curves and the classical Yang–Baxter equation
Authors: Burban Igor , Henrich Thilo
Published: March 2015

In this article, we develop a geometric method to construct solutions of the classical Yang–Baxter equation, attaching a family of classical

r

-matrices to the Weierstrass family of plane cubic curves and a pair of coprime positive integers. It turns out that all elliptic

r

-matrices arise in this way from smooth cubic curves. For the cuspidal cubic curve, we prove that the obtained solutions are rational and compute them explicitly. We also describe them in terms of Stolin's classification and prove that they are degenerations of the corresponding elliptic solutions.
Error Analysis for a Non-Monotone FEM for a Singularly Perturbed Problem with Two Small Parameters
Authors: Chen Yanping , Leng Haitao , Liu Li-Bin
Published: March 2015

In this paper, we consider a singularly perturbed convection-diffusion problem. The problem involves two small parameters that gives rise to two boundary layers at two endpoints of the domain. For this problem, a non-monotone finite element methods is used. A priori error bound in the maximum norm is obtained. Based on the a priori error bound, we show that there exists Bakhvalov-type mesh that gives optimal error bound of (N−2) which is robust with respect to the two perturbation parameters. Numerical results are given that confirm the theoretical result.
A Comparison and Unification of Ellipsoidal Statistical and Shakhov BGK Models
Authors: Chen Songze , Xu Kun , Cai Qingdong
Published: March 2015

The Ellipsoidal Statistical model (ES-model) and the Shakhov model (Smodel) were constructed to correct the Prandtl number of the original BGK model through the modification of stress and heat flux. With the introduction of a new parameter to combine the ES-model and S-model, a generalized kinetic model can be developed. This new model can give the correct Navier-Stokes equations in the continuum flow regime. Through the adjustment of the new parameter, it provides abundant dynamic effect beyond the ES-model and S-model. Changing the free parameter, the physical performance of the new model has been tested numerically. The unified gas kinetic scheme (UGKS) is employed for the study of the new model. In transition flow regime, many physical problems, i.e., the shock structure and micro-flows, have been studied using the generalized model. With a careful choice of the free parameter, good results can be achieved for most test cases. Due to the property of the Boltzmann collision integral, the new parameter in the generalized kinetic model cannot be fully determined. It depends on the specific problem. Generally speaking, the Smodel predicts more accurate numerical solutions in most test cases presented in this paper than the ES-model, while ES-model performs better in the cases where the flow is mostly driven by temperature gradient, such as a channel flow with large boundary temperature variation at high Knudsen number.
Evidence for tropospheric wind shear excitation of high-phase-speed gravity waves reaching the mesosphere using the ray-tracing technique
Authors: Pramitha M. , Venkat Ratnam M. , Taori A. , Krishna Murthy B. V. , Pallamraju D. , Vijaya Bhaskar Rao S.
Published: March 2015

Abstract. Sources and propagation characteristics of high-frequency gravity waves observed in the mesosphere using airglow emissions from Gadanki (13.5° N, 79.2° E) and Hyderabad (17.5° N, 78.5° E) are investigated using reverse ray tracing. Wave amplitudes are also traced back, including both radiative and diffusive damping. The ray tracing is performed using background temperature and wind data obtained from the MSISE-90 and HWM-07 models, respectively. For the Gadanki region, the suitability of these models is tested. Further, a climatological model of the background atmosphere for the Gadanki region has been developed using nearly 30 years of observations available from a variety of ground-based (MST radar, radiosondes, MF radar) and rocket- and satellite-borne measurements. ERA-Interim products are utilized for constructing background parameters corresponding to the meteorological conditions of the observations. With the reverse ray-tracing method, the source locations for nine wave events could be identified to be in the upper troposphere, whereas for five other events the waves terminated in the mesosphere itself. Uncertainty in locating the terminal points of wave events in the horizontal direction is estimated to be within 50–100 km and 150–300 km for Gadanki and Hyderabad wave events, respectively. This uncertainty arises mainly due to non-consideration of the day-to-day variability in the tidal amplitudes. Prevailing conditions at the terminal points for each of the 14 events are provided. As no convection in and around the terminal points is noticed, convection is unlikely to be the source. Interestingly, large (~9 m s−1km−1) vertical shears in the horizontal wind are noticed near the ray terminal points (at 10–12 km altitude) and are thus identified to be the source for generating the observed high-phase-speed, high-frequency gravity waves.
Competition between core and periphery-based processes in warm convective clouds – from invigoration to suppression
Authors: Dagan G. , Koren I. , Altaratz O.
Published: March 2015

Abstract. How do changes in the amount and properties of aerosol affect warm clouds? Recent studies suggest that they have opposing effects. Some suggest that an increase in aerosol loading leads to enhanced evaporation and therefore smaller clouds, whereas other studies suggest clouds' invigoration. In this study, using an axisymmetric bin-microphysics cloud model, we propose a theoretical scheme that analyzes the evolution of key processes in warm clouds, under different aerosol loading and environmental conditions, to explain this contradiction. Such an analysis of the key processes reveals a robust reversal in the trend of the clouds' response to an increase in aerosol loading. When aerosol conditions are shifted from superpristine to slightly polluted, the clouds formed are deeper and have larger water mass. Such a trend continues up to an optimal concentration (Nop) that allows the cloud to achieve a maximal water mass. Hence, for any concentration below Nop the cloud formed contains less mass and therefore can be considered as aerosol-limited, whereas for concentrations greater thanNop cloud periphery processes, such as enhanced entrainment and evaporation, take over leading to cloud suppression. We show that Nop is a function of the thermodynamic conditions (temperature and humidity profiles). Thus, profiles that favor deeper clouds would dictate larger values of Nop, whereas for profiles of shallow convective clouds, Nop corresponds to the pristine range of the aerosol loading. Such a view of a trend reversal, marked by the optimal concentration, Nop, helps one to bridge the gap between the contradictory results of numerical models and observations. Satellite studies are biased in favor of larger clouds that are characterized by larger Nop values and therefore invigoration is observed. On the other hand, modeling studies of cloud fields are biased in favor of small, mostly trade-like convective clouds, which are characterized by low Nop values (in the pristine range) and, therefore, cloud suppression is mostly reported as a response to an increase in aerosol loading.
Biomass burning related ozone damage on vegetation over the Amazon forest: a model sensitivity study
Authors: Pacifico F. , Folberth G. A. , Sitch S. , Haywood J. M. , Rizzo L. V. , Malavelle F. F. , Artaxo P.
Published: March 2015

Abstract. The HadGEM2 earth system climate model was used to assess the impact of biomass burning on surface ozone concentrations over the Amazon forest and its impact on vegetation, under present-day climate conditions. Here we consider biomass burning emissions from wildfires, deforestation fires, agricultural forest burning, and residential and commercial combustion. Simulated surface ozone concentration is evaluated against observations taken at two sites in the Brazilian Amazon forest for years 2010 to 2012. The model is able to reproduce the observed diurnal cycle of surface ozone mixing ratio at the two sites, but overestimates the magnitude of the monthly averaged hourly measurements by 5–15 ppb for each available month at one of the sites. We vary biomass burning emissions over South America by ±20, 40, 60, 80 and 100% to quantify the modelled impact of biomass burning on surface ozone concentrations and ozone damage on vegetation productivity over the Amazon forest. We used the ozone damage scheme in the "high" sensitivity mode to give an upper limit for this effect. Decreasing South American biomass burning emissions by 100% (i.e. to zero) reduces surface ozone concentrations (by about 15 ppb during the biomass burning season) and suggests a 15% increase in monthly mean net primary productivity averaged over the Amazon forest, with local increases up to 60%. The simulated impact of ozone damage from present-day biomass burning on vegetation productivity is about 230 TgC yr−1. Taking into account that uncertainty in these estimates is substantial, this ozone damage impact over the Amazon forest is of the same order of magnitude as the release of carbon dioxide due to fire in South America; in effect it potentially doubles the impact of biomass burning on the carbon cycle.
Influence of the aerosol solar extinction on photochemistry during the 2010 Russian wildfires episode
Authors: Péré J. C. , Bessagnet B. , Pont V. , Mallet M. , Minvielle F.
Published: March 2015

Abstract. In this work, impact of aerosol solar extinction on the photochemistry over eastern Europe during the 2010 wildfires episode is discussed for the period from 5 to 12 August 2010, which coincides to the peak of fire activity. The methodology is based on an on-line coupling between the chemistry-transport model CHIMERE (extended by an aerosol optical module) and the radiative transfer code TUV. Results of simulations indicate an important influence of the aerosol solar extinction, in terms of intensity and spatial extent, with a reduction of the photolysis rates of NO2 and O3 up to 50% (in diurnal-averaged) along the aerosol plume transport. At a regional scale, these changes in photolysis rates lead to a 3–15% increase in the NO2 daytime concentration and to an ozone reduction near the surface of 1–12%. The ozone reduction is shown to occur over the entire boundary layer, where aerosols are located. Also, comparisons of simulations with air quality measurements over Moscow show that the inclusion of the aerosol feedback tends to slightly improve performance of the model in simulating NO2 and O3 ground concentrations. In term of air quality prediction, the O3 peak reduction when including aerosol feedback results in a non-negligible difference in the predicted exceedance of alert threshold compared to the simulation without aerosol feedback, in coherence with measurements. Finally, the total aerosol mass concentration (PM10) is shown to be decreased by 1–2 %, on average during the studied period, caused by a reduced formation of secondary aerosols such as sulphates and secondary organics (4–10%) when aerosol impact on photolysis rates is included.
Seasonal variation of secondary organic aerosol in Nam Co, Central Tibetan Plateau
Authors: Shen R.-Q. , Ding X. , He Q.-F. , Cong Z.-Y. , Yu Q.-Q. , Wang X.-M.
Published: March 2015

Abstract. Secondary organic aerosol (SOA) affects the earth's radiation balance and global climate. High-elevation areas are sensitive to global climate change. However, at present, SOA origins and seasonal variations are understudied in remote high-elevation areas. In this study, particulate samples were collected from July 2012 to July 2013 at the remote Nam Co (NC) site, Central Tibetan Plateau and analyzed for SOA tracers from biogenic (isoprene, monoterpenes and β-caryophyllene) and anthropogenic (aromatics) precursors. Among these compounds, isoprene SOA (SOAI) tracers represented the majority (26.6 ± 44.2 ng m−3), followed by monoterpene SOA (SOAM) tracers (0.97 ± 0.57 ng m−3), aromatic SOA (SOAA) tracer (2,3-dihydroxy-4-oxopentanoic acid, DHOPA, 0.25 ± 0.18 ng m−3) and β-caryophyllene SOA tracer (β-caryophyllenic acid, 0.09 ± 0.10 ng m−3). SOAI tracers exhibited high concentrations in the summer and low levels in the winter. The similar temperature dependence of SOAI tracers and isoprene emission suggested that the seasonal variation of SOAI at the NC site was mainly influenced by isoprene emission. The ratio of high-NOx to low-NOx products of isoprene (2-methylglyceric acid to 2-methyltetrols) was the highest in the winter and the lowest in the summer, due to the influence of temperature and relative humidity. The seasonal variation of SOAM tracers was impacted by monoterpenes emission and tracers partitioning. The similar temperature dependence of SOAM tracers and monoterpenes emission was only observed during winter to spring. SOAM tracer levels did not elevate with increased temperature in the summer, probably resulting from the counteraction of temperature effects on gas/particle partitioning and monoterpenes emission. The concentrations of DHOPA were 1–2 orders of magnitude lower than those reported in the urban regions of the world. Due to the transport of air pollutants from the adjacent Bangladesh and the eastern India, DHOPA presented relatively higher levels in the summer. In the winter when air masses mainly came from the northwestern India, mass fractions of DHOPA in total tracers increased, although its concentrations declined. The SOA-tracer method was applied to estimated secondary organic carbon (SOC) from these four precursors. The annual average of SOC was 0.22 ± 0.29 μg C m−3, with the biogenic SOC (sum of isoprene, monoterpenes and β-caryophyllene) accounting for 75%. In the summer, isoprene was the major precursor with its SOC contributions of 81%. In the winter when the emission of biogenic precursors largely dropped, the contributions of aromatic SOC increased. Our study implies that anthropogenic pollutants emitted in the Indian subcontinent could transport to the TP and have impact on SOC over the remote NC.
A simple formulation of the CH2O photolysis quantum yields
Authors: Röth E.-P. , Ehhalt D. H.
Published: March 2015

Abstract. New expressions for the various wavelength – dependent photolysis quantum yields of CH2O, Φj, are presented. They are based on combinations of functions of the type Ai/(1 + exp[−(1/λ −1/λ 0i)/bi]). The parameters Ai, bi, and λ0i which have a physical meaning are obtained by fits to the measured data of the Φji available from the literature. The altitude dependence of the photolysis frequencies resulting from the new quantum yield expressions are compared to those derived from the Φj recommended by JPL and IUPAC.
A new electrodynamic balance (EDB) design for low-temperature studies: application to immersion freezing of pollen extract bioaerosols
Authors: Tong H.-J. , Ouyang B. , Nikolovski N. , Lienhard D. M. , Pope F. D. , Kalberer M.
Published: March 2015

Abstract. In this paper we describe a newly designed cold electrodynamic balance(CEDB) system, built to study the evaporation kinetics and freezing properties of supercooled water droplets. The temperature of the CEDB chamber at the location of the levitated water droplet can be controlled in the range −40 to +40 °C, which is achieved using a combination of liquid nitrogen cooling and heating by positive temperature coefficient heaters. The measurement of liquid droplet radius is obtained by analysing the Mie elastic light scattering from a 532 nm laser. The Mie scattering signal was also used to characterise and distinguish droplet freezing events; liquid droplets produce a regular fringe pattern, whilst the pattern from frozen particles is irregular. The evaporation rate of singly levitated water droplets was calculated from time-resolved measurements of the radii of evaporating droplets and a clear trend of the evaporation rate on temperature was measured. The statistical freezing probabilities of aqueous pollen extracts (pollen washing water) are obtained in the temperature range −4.5 to −40 °C. It was found that that pollen washing water from water birch (Betula fontinalis occidentalis) pollen can act as ice nuclei in the immersion freezing mode at temperatures as warm as −22.45 (±0.65) °C. Furthermore it was found that the protein-rich component of the washing water was significantly more ice-active than the non-proteinaceous component.
Dinitrogen fixation and dissolved organic nitrogen fueled primary production and particulate export during the VAHINE mesocosms experiment (New Caledonia lagoon)
Authors: Berthelot H. , Moutin T. , L'Helguen S. , Leblanc K. , Hélias S. , Grosso O. , Leblond N. , Charrière B. , Bonnet S.
Published: March 2015

Abstract. In the oligotrophic ocean characterized by nitrate (NO3-) depletion in surface waters, dinitrogen (N2) fixation and dissolved organic nitrogen (DON) can represent significant nitrogen (N) sources for the ecosystem. Here we deployed in New Caledonia large in situ mesocosms in order to investigate (1) the contribution of N2 fixation and DON use to primary production (PP) and particle export and (2) the fate of the freshly produced particulate organic N (PON) i.e. whether it is preferentially accumulated and recycled in the water column or exported out of the system. The mesocosms were fertilized with phosphate (P) in order to prevent P-limitation and promote N2 fixation. The diazotrophic community was dominated by diatoms-diazotrophs associations (DDAs) during the first part of the experiment for 10 days (P1) followed by the unicellular N2-fixing cyanobacteria UCYN-C the 9 last days (P2) of the experiment. N2 fixation rates averaged 9.8 ± 4.0 and 27.7 ± 8.6 nM d−1 during P1 and P2, respectively. NO3- concentrations (< 40 nM) in the mesocosms were a negligible source of N indicating that N2 fixation was the main driver of new production all along the experiment. The contribution of v fixation to PP was not significantly different (p > 0.05) during P1 (9.0 ± 3.3%) and P2 (12.6 ± 6.1%). However, the e ratio that quantifies the efficiency of a system to export particulate organic carbon (POCexport) compared to PP (e ratio = POCexport/PP) was significantly higher (p < 0.05) during P2 (39.7 ± 24.9%) than during P1 (23.9 ± 20.2%) indicating that the production sustained by UCYN-C was more efficient at promoting C export than the production sustained by DDAs. During P1, PON was stable and the total amount of N provided by N2 fixation (0.10 ± 0.02 μM) was not significantly different (p > 0.05) from the total amount of PON exported (0.10 ± 0.04 μM), suggesting a rapid and probably direct export of the recently fixed N2 by the DDAs. During P2, both PON concentrations and PON export increased in the mesocosms by a factor 1.5–2. Unlike in P1, this PON production was not totally explained by the new N provided by N2 fixation. The use of DON, whose concentrations decreased significantly (p < 0.05) from 5.3 ± 0.5 μM to 4.4 ± 0.5 μM, appeared to be the missing N source. The DON consumption of about 0.9 μM during P2 is even higher than the total amount of new N brought by N2 fixation (about 0.25 μM) during the same period. These results suggest that while DDAs mainly rely on N2 fixation for their N requirement, both N2 fixation and DON can be significant N-sources for primary production and particulate export following UCYN-C blooms in the New Caledonia lagoon and by extension in the N-limited Ocean where similar events are likely to occur.
Methods for automatized detection of rapid changes in lateral boundary condition fields for NWP limited area models
Authors: Tudor M.
Published: March 2015

Abstract. Three hourly temporal resolution of lateral boundary data can be too low to properly resolve rapidly moving storms. This problem is expected to be worse with increasing horizontal resolution. In order to detect intensive disturbances in surface pressure moving rapidly through the model domain, a filtered surface pressure field (MCUF) is computed operationally in the ARPEGE global model of Météo France. The field is distributed in the coupling files along with conventional meteorological fields used for lateral boundary conditions (LBCs) for the operational forecast using limited area model ALADIN in the Meteorological and hydrological service of Croatia (DHMZ). Here an analysis is performed of the MCUF field for the LACE coupling domain for the period since 23 January 2006, when it became available, until 15 November 2014. The MCUF field is a good indicator of rapidly moving pressure disturbances (RMPDs). Its spatial and temporal distribution can be associated to the usual cyclone tracks and areas known to be supporting cyclogenesis. Other global models do not compute such field. Alternative set of coupling files from IFS operational run in ECMWF is also available operationally in DHMZ with 3 hourly temporal resolution but the MCUF field is not available. Here, several methods are tested that detect RMPDs in surface pressure a posteriori from the IFS model fields provided in the coupling files. MCUF is computed by running ALADIN on the coupling files from IFS. The error function is computed using one time step integration of ALADIN on the coupling files without initialization, initialized with DFI or SSDFI. Finally, the amplitude of changes in the mean sea level pressure is computed from the fields in the coupling files. The results are compared to the MCUF field of ARPEGE and the results of same methods applied to the coupling files from ARPEGE. Most methods give a signal for the rapidly moving pressure disturbances (RMPDs), but DFI reduces the storms too much to be detected. Error function without filtering and amplitude have more noise, but the signal of a RMPD is also stronger. The methods are tested for NWP LAM, but could be applied to and benefit the performance of climate LAMs.
Fractional snow-covered area parameterization over complex topography
Authors: Helbig N. , van Herwijnen A. , Magnusson J. , Jonas T.
Published: March 2015

Abstract. Fractional snow-covered area (SCA) is a key parameter in large-scale hydrological, meteorological and regional climate models. Since SCA affects albedos and surface energy balance fluxes, it is especially of interest over mountainous terrain where generally a reduced SCA is observed in large grid cells. Temporal and spatial snow distributions are, however, difficult to measure over complex topography. We therefore present a parameterization of SCA based on a new subgrid parameterization for the standard deviation of snow depth over complex topography. Highly resolved snow depth data at the peak of winter were used from two distinct climatic regions, in eastern Switzerland and in the Spanish Pyrenees. Topographic scaling parameters are derived assuming Gaussian slope characteristics. We use computationally cheap terrain parameters, namely, the correlation length of subgrid topographic features and the mean squared slope. A scale dependent analysis was performed by randomly aggregating the alpine catchments in domain sizes ranging from 50 m to 3 km. For the larger domain sizes, snow depth was predominantly normally distributed. Trends between terrain parameters and standard deviation of snow depth were similar for both climatic regions, allowing one to parameterize the standard deviation of snow depth based on terrain parameters. To make the parameterization widely applicable, we introduced the mean snow depth as a climate indicator. Assuming a normal snow distribution and spatially homogeneous melt, snow-cover depletion (SCD) curves were derived for a broad range of coefficients of variations. The most accurate closed form fit resembled an existing fractional SCA parameterization. By including the subgrid parameterization for the standard deviation of snow depth, we extended the fractional SCA parameterization for topographic influences. For all domain sizes we obtained errors lower than 10% between measured and parameterized SCA.
Sensibility analysis of VORIS lava-flow simulations: application to Nyamulagira volcano, Democratic Republic of Congo
Authors: Syavulisembo A. M. , Havenith H.-B. , Smets B. , d'Oreye N. , Marti J.
Published: March 2015

Abstract. Assessment and management of volcanic risk are important scientific, economic, and political issues, especially in densely populated areas threatened by volcanoes. The Virunga area in the Democratic Republic of Congo, with over 1 million inhabitants, has to cope permanently with the threat posed by the active Nyamulagira and Nyiragongo volcanoes. During the past century, Nyamulagira erupted at intervals of 1–4 years – mostly in the form of lava flows – at least 30 times. Its summit and flank eruptions lasted for periods of a few days up to more than two years, and produced lava flows sometimes reaching distances of over 20 km from the volcano, thereby affecting very large areas and having a serious impact on the region of Virunga. In order to identify a useful tool for lava flow hazard assessment at the Goma Volcano Observatory (GVO), we tested VORIS 2.0.1 (Felpeto et al., 2007), a freely available software (http://www.gvb-csic.es) based on a probabilistic model that considers topography as the main parameter controlling lava flow propagation. We tested different Digital Elevation Models (DEM) – SRTM1, SRTM3, and ASTER GDEM – to analyze the sensibility of the input parameters of VORIS 2.0.1 in simulation of recent historical lava-flow for which the pre-eruption topography is known. The results obtained show that VORIS 2.0.1 is a quick, easy-to-use tool for simulating lava-flow eruptions and replicates to a high degree of accuracy the eruptions tested. In practice, these results will be used by GVO to calibrate VORIS model for lava flow path forecasting during new eruptions, hence contributing to a better volcanic crisis management.