bluuebunny/crossref_metadata_2025 huggingface dataset:
Sensitivity of tropospheric chemical composition to halogen-radical chemistry using a fully coupled size-resolved multiphase chemistry–global climate system: halogen distributions, aerosol composition, and sensitivity of climate-relevant gases
Authors: Long M. S. , Keene W. C. , Easter R. C. , Sander R. , Liu X. , Kerkweg A. , Erickson D.
Published: April 2014

Abstract. Observations and model calculations indicate that highly non-linear multiphase atmospheric processes involving inorganic Cl and Br significantly impact tropospheric chemistry and composition, aerosol evolution, and radiative transfer. The sensitivity of global atmospheric chemistry to the production of marine aerosol and the associated activation and cycling of inorganic Cl and Br was investigated using a size-resolved multiphase coupled chemistry–global climate model (National Center for Atmospheric Research's Community Atmosphere Model (CAM) v3.6.33). Simulated results revealed strong meridional and vertical gradients in Cl and Br species. They also point to possible physicochemical mechanisms that may account for several previously unexplained phenomena, including the enrichment of Br- in submicron aerosol and the presence of a BrO maximum in the polar free troposphere. However, simulated total volatile inorganic Br mixing ratios in the troposphere were generally higher than observed, due in part to the overly efficient net production of BrCl. In addition, the emission scheme for marine aerosol and associated Br−, which is the only source for Br in the model, overestimates emission fluxes from the high-latitude Southern Ocean. Br in the stratosphere was lower than observed due to the lack of long-lived precursor organobromine species in the simulation. Comparing simulations using chemical mechanisms with and without reactive Cl and Br species demonstrates a significant temporal and spatial sensitivity of primary atmospheric oxidants (O3, HOx, NOx), CH4, non-methane hydrocarbons (NMHCs), and dimethyl sulfide (DMS) to halogen cycling. Globally, halogen chemistry had relatively less impact on SO2 and non-sea-salt (nss) SO42− although significant regional differences were evident. Although variable geographically, much of this sensitivity is attributable to either over-vigorous activation of Br (primarily BrCl) via the chemical mechanism or overproduction of sea-salt aerosol simulated under higher-wind regimes. In regions where simulated mixing ratios of reactive Br and Cl fell within observed ranges, though, halogen chemistry drove large changes in oxidant fields and associated chemical processes relative to simulations with no halogens. However, the overall simulated impacts of Br chemistry globally are overestimated and thus caution is warranted in their interpretation.
Chlorine as a primary radical: evaluation of methods to understand its role in initiation of oxidative cycles
Authors: Young C. J. , Washenfelder R. A. , Edwards P. M. , Parrish D. D. , Gilman J. B. , Kuster W. C. , Mielke L. H. , Osthoff H. D. , Tsai C. , Pikelnaya O. , Stutz J. , Veres P. R. , Roberts J. M. , Griffith S. , Dusanter S. , Stevens P. S. , Flynn J. , Grossberg N. , Lefer B. , Holloway J. S. , Peischl J. , Ryerson T. B. , Atlas E. L. , Blake D. R. , Brown S. S.
Published: April 2014

Abstract. The role of chlorine atoms (Cl) in atmospheric oxidation has been traditionally thought to be limited to the marine boundary layer, where they are produced through heterogeneous reactions involving sea salt. However, recent observation of photolytic Cl precursors (ClNO2 and Cl2) formed from anthropogenic pollution has expanded the potential importance of Cl to include coastal and continental urban areas. Measurements of ClNO2 in Los Angeles during CalNex (California Nexus – Research at the Nexus of Air Quality and Climate Change) showed it to be an important primary (first generation) radical source. Evolution of ratios of volatile organic compounds (VOCs) has been proposed as a method to quantify Cl oxidation, but we find no evidence from this approach for a significant role of Cl oxidation in Los Angeles. We use a box model with the Master Chemical Mechanism (MCM v3.2) chemistry scheme, constrained by observations in Los Angeles, to examine the Cl sensitivity of commonly used VOC ratios as a function of NOx and secondary radical production. Model results indicate VOC tracer ratios could not detect the influence of Cl unless the ratio of [OH] to [Cl] was less than 200 for at least a day. However, the model results also show that secondary (second generation) OH production resulting from Cl oxidation of VOCs is strongly influenced by NOx, and that this effect obscures the importance of Cl as a primary oxidant. Calculated concentrations of Cl showed a maximum in mid-morning due to a photolytic source from ClNO2 and loss primarily to reactions with VOCs. The [OH] to [Cl] ratio was below 200 for approximately 3 h in the morning, but Cl oxidation was not evident from the measured ratios of VOCs. Instead, model simulations show that secondary OH production causes VOC ratio evolution to follow that expected for OH oxidation, despite the significant input of primary Cl from ClNO2 photolysis in the morning. Even though OH is by far the dominant oxidant in Los Angeles, Cl atoms do play an important role in photochemistry there, constituting 9% of the primary radical source. Furthermore, Cl–VOC reactivity differs from that of OH, being more than an order of magnitude larger and dominated by VOCs, such as alkanes, that are less reactive toward OH. Primary Cl is also slightly more effective as a radical source than primary OH due to its greater propensity to initiate radical propagation chains via VOC reactions relative to chain termination via reaction with nitrogen oxides.
Diagnosing the average spatio-temporal impact of convective systems – Part 2: A model inter-comparison using satellite data
Authors: Johnston M. S. , Eliasson S. , Eriksson P. , Forbes R. M. , Gettelman A. , Räisänen P. , Zelinka M. D.
Published: April 2014

Abstract. The representation of the effect of tropical deep convective (DC) systems on upper-tropospheric moist processes and outgoing longwave radiation (OLR) is evaluated in the climate models EC-Earth, ECHAM6, and CAM5 using satellite observations. A composite technique is applied to thousands of deep convective systems that are identified using local rain rate (RR) maxima in order to focus on the temporal evolution of the deep convective processes in the model and observations. The models tend to over-produce rain rates less than about 3 mm h−1 and underpredict the occurrence of more intense rain. While the diurnal distribution of oceanic rain rate maxima in the models is similar to the observations, the land-based maxima are out of phase. Over land, the diurnal cycle of rain is too intense, with DC events occurring at the same position on subsequent days, while the observations vary more in timing and geographical location. Despite having a larger climatological mean upper tropospheric relative humidity, models closely capture the observed moistening of the upper troposphere following the peak rain rate in the deep convective systems. A comparison of the evolution of vertical profiles of ice water content and cloud fraction shows significant differences between models and with the observations. Simulated cloud fractions near the tropopause are also larger than observed, but the corresponding ice water contents are smaller compared to the observations. EC-Earth's CF at pressure levels > 300 hPa are generally less than the obervations while the other models tend to have larger CF for similar altitudes. The models' performance for ocean-based systems seems to capture the evolution of DC systems fairly well, but the land-based systems show significant discrepancies. In particular, the models have a significantly stronger diurnal cycle at the same geo-spatial position. Finally, OLR anomalies associated with deep convection are in reasonable agreement with the observations. This study shows that such agreement with observations can be achieved in different ways in the three models due to different representations of deep convection processes and compensating errors.
Effect of different emission inventories on modeled ozone and carbon monoxide in Southeast Asia
Authors: Amnuaylojaroen T. , Barth M. C. , Emmons L. K. , Carmichael G. R. , Kreasuwun J. , Prasitwattanaseree S. , Chantara S.
Published: April 2014

Abstract. In order to improve our understanding of air quality in Southeast Asia, the anthropogenic emissions inventory must be well represented. In this work, we apply different anthropogenic emission inventories in the Weather Research and Forecasting Model with Chemistry (WRF-Chem) version 3.3 using MOZART gas-phase chemistry and GOCART aerosols to examine the differences in predicted carbon monoxide (CO) and ozone (O3) surface mixing ratios for Southeast Asia in March and December 2008. The anthropogenic emission inventories include the Reanalysis of the TROpospheric chemical composition (RETRO), the Intercontinental Chemical Transport Experiment-Phase B (INTEX-B), the MACCity emissions (adapted from the Monitoring Atmospheric Composition and Climate and megacity Zoom for the Environment projects), the Southeast Asia Composition, Cloud, Climate Coupling Regional Study (SEAC4RS) emissions, and a combination of MACCity and SEAC4RS emissions. Biomass burning emissions are from the Fire Inventory from NCAR (FINNv1) model. WRF-chem reasonably predicts the 2 m temperature, 10 m wind, and precipitation. In general, surface CO is underpredicted by WRF-Chem while surface O3 is overpredicted. The NO2 tropospheric column predicted by WRF-Chem has the same magnitude as observations, but tends to underpredict NO2 column over the equatorial ocean and near Indonesia. Simulations using different anthropogenic emissions produce only a slight variability of O3 and CO mixing ratios, while biomass burning emissions add more variability. The different anthropogenic emissions differ by up to 20% in CO emissions, but O3 and CO mixing ratios differ by ~4.5% and ~8%, respectively, among the simulations. Biomass burning emissions create a substantial increase for both O3 and CO by ~29% and ~16%, respectively, when comparing the March biomass burning period to December with low biomass burning emissions. The simulations show that none of the anthropogenic emission inventories are better than the others and any of the examined inventories can be used for air quality simulations in Southeast Asia.
Light scattering at small angles by atmospheric irregular particles: modelling and laboratory measurements
Authors: Lurton T. , Renard J.-B. , Vignelles D. , Jeannot M. , Akiki R. , Mineau J.-L. , Tonnelier T.
Published: April 2014

Abstract. We have investigated the behaviour of light scattering by particulates of various sizes (0.1 μm to 100 μm) at a small scattering angle (below 20°). It has been previously shown that, for a small angle, the scattered intensities are weakly dependent upon the particulates' composition (Renard et al., 2010). Particles found in the atmosphere exhibit roughness that leads to large discrepancies with the classical Mie solution in terms of scattered intensities in the low angular set-up. This article focuses on building an effective theoretical tool to predict the behaviour of light scattering by real particulates at a small scattering angle. We present both the classical Mie theory and its adaptation to the case of rough particulates with a fairly simple roughness parameterisation. An experimental device was built, corresponding to the angular set-up of interest (low scattering angle and therefore low angular aperture). Measurements are presented that confirm the theoretical results with good agreement. It was found that differences between the classical Mie solution and actual measurements – especially for large particulates – can be attributed to the particulate roughness. It was also found that, in this low angular set-up, saturation of the scattered intensities occurs for relatively small values of the roughness parameter. This confirms the low variability in the scattered intensities observed for atmospheric particulates of different kinds. A direct interest of this study is a broadening of the dynamic range of optical counters: using a small angle of aperture for measurements allows greater dynamics in terms of particle size. Thus it allows a single device to observe a broad range of particle sizes whilst utilising the same electronics.
Atmospheric composition and thermodynamic retrievals from the ARIES airborne TIR-FTS system – Part 2: Validation and results from aircraft campaigns
Authors: Allen G. , Illingworth S. M. , O'Shea S. J. , Newman S. , Vance A. , Bauguitte S. J.-B. , Marenco F. , Kent J. , Bower K. , Gallagher M. W. , Muller J. , Percival C. J. , Harlow C. , Lee J. , Taylor J. P.
Published: April 2014

Abstract. This study validates trace gas and thermodynamic retrievals from nadir infrared spectroscopic measurements recorded by the UK Met Office Airborne Research Interferometer Evaluation System (ARIES) – a Thermal InfraRed Fourier Transform Spectrometer (TIR-FTS) on the UK Facility for Airborne Atmospheric Measurements (FAAM) BAe-146 aircraft. Trace-gas-concentration and thermodynamic profiles have been retrieved and validated for this study throughout the troposphere and planetary boundary layer over a range of environmental variability using data from aircraft campaigns over and around London, the US Gulf Coast, and the Arctic Circle during the ClearfLo, JAIVEX, and MAMM aircraft campaigns, respectively. Vertically-resolved retrievals of temperature and water vapour (H2O), and partial-column retrievals of methane (CH4), carbon monoxide (CO), and ozone (O3), over both land and sea, were compared to corresponding measurements from high-precision in-situ analysers and dropsondes operated on the FAAM aircraft. Average Degrees of Freedom for Signal (DOFS) over a 0–9 km column range were found to be 4.97, 3.11, 0.91, 1.10, and 1.62 for temperature, H2O, CH4, CO, and O3, respectively, when retrieved on 10 vertical levels. Partial column mean biases (and 1σ bias) averaged across all flight campaigns were −0.4 (±1.9)%, −6.0 (±13.1)%, −0.6 (±2.1)%, −3.0(±18.4)%, and +4.7 (±24.9)%, respectively, while the typical total a posteriori errors for individually retrieved profiles were 0.4%, 9.5%, 5.0%, 21.2%, and 15.0%, respectively. Averaging kernels derived for progressively lower altitudes show improving sensitivity to lower atmospheric layers when flying at lower altitudes. Temperature and H2O display significant vertically resolved sensitivity throughout the column, whilst trace gases are usefully retrieved only as partial column quantities, with maximal sensitivity for trace gases other than H2O within a layer 1 km and 2 km below the aircraft. This study demonstrates the valuable atmospheric composition information content that can be obtained by ARIES nadir TIR remote sensing for atmospheric process studies.
Derivation of tropospheric methane from TCCON CH4 and HF total column observations
Authors: Saad K. M. , Wunch D. , Toon G. C. , Bernath P. , Boone C. , Connor B. , Deutscher N. M. , Griffith D. W. T. , Kivi R. , Notholt J. , Roehl C. , Schneider M. , Sherlock V. , Wennberg P. O.
Published: April 2014

Abstract. The Total Carbon Column Observing Network (TCCON) is a global ground-based network of Fourier transform spectrometers that produce precise measurements of column-averaged dry-air mole fractions of atmospheric methane (CH4). Temporal variability in the total column of CH4 due to stratospheric dynamics obscures fluctuations and trends driven by tropospheric transport and local sources and sinks. We remove the contribution of stratospheric variability from the total column average by subtracting an estimate of the stratospheric CH4 derived from simultaneous measurements of hydrogen fluoride (HF). HF provides a proxy for stratospheric CH4 because it resides solely in the stratosphere, has a nearly linear inverse relationship with stratospheric CH4, and is measured at most TCCON stations. The stratospheric partial column of CH4 is calculated as a function of the zonal and annual trends in the relationship between CH4 and HF in the stratosphere, which we determine from ACE-FTS satellite data. We also explicitly take into account the CH4 column averaging kernel to estimate the contribution of stratospheric CH4 to the total column. The resulting tropospheric CH4 columns are consistent with in situ aircraft measurements and augment existing observations in the troposphere.
Application of spectral analysis techniques to the intercomparison of aerosol data – Part 4: Combined maximum covariance analysis to bridge the gap between multi-sensor satellite retrievals and ground-based measurements
Authors: Li J. , Carlson B. E. , Lacis A. A.
Published: April 2014

Abstract. The development of remote sensing techniques has greatly advanced our knowledge of atmospheric aerosols. Various satellite sensors and the associated retrieval algorithms all add to the information of global aerosol variability, while well-designed surface networks provide time series of highly accurate measurements at specific locations. In studying the variability of aerosol properties, aerosol climate effects, and constraining aerosol fields in climate models, it is essential to make the best use of all of the available information. In the previous three parts of this series, we demonstrated the usefulness of several spectral decomposition techniques in the analysis and comparison of temporal and spatial variability of aerosol optical depth using satellite and ground-based measurements. Specifically, Principal Component Analysis (PCA) successfully captures and isolates seasonal and interannual variability from different aerosol source regions, Maximum Covariance Analysis (MCA) provides a means to verify the variability in one satellite dataset against Aerosol Robotic Network (AERONET) data, and Combined Principal Component Analysis (CPCA) realized parallel comparison among multi-satellite, multi-sensor datasets. As the final part of the study, this paper introduces a novel technique that integrates both multi-sensor datasets and ground observations, and thus effectively bridges the gap between these two types of measurements. The Combined Maximum Covariance Analysis (CMCA) decomposes the cross covariance matrix between the combined multi-sensor satellite data field and AERONET station data. We show that this new method not only confirms the seasonal and interannual variability of aerosol optical depth, aerosol source regions and events represented by different satellite datasets, but also identifies the strengths and weaknesses of each dataset in capturing the variability associated with sources, events or aerosol types. Furthermore, by examining the spread of the spatial modes of different satellite fields, regions with the largest uncertainties in aerosol observation are identified. We also present two regional case studies that respectively demonstrate the capability of the CMCA technique in assessing the representation of an extreme event in different datasets, and in evaluating the performance of different datasets on seasonal and interannual time scales.
Disturbances can control fine-scale pedodiversity in old-growth forest: is the soil evolution theory disturbed as well?
Authors: Šamonil P. , Vašíčková I. , Daněk P. , Janík D. , Adam D.
Published: April 2014

Abstract. Biota–soil interaction in natural ecosystems is an area of considerable research. Our hypothesis is that individual trees play a significant role through biomechanical and biochemical disturbances in soil formation in temperate forest resulting in complex spatial pattern of disturbance regimes and a close relationship between disturbance histories and soil units. In Žofínský Prales (Czech Republic) – the fourth oldest, continuously protected reserve in Europe and the only SIGEO site in continental Europe – in time and space we compared extensive dendrochronological, soil and pit-mound microtopography data on an area of 42.01 ha collected in 2008–2012. The datasets differ in terms of information complexity and length of memory. Tree cores contain complex information about disturbance history of the past 350 years, footprints of the specific tree uprooting disturbance can persist 1700 years, and soils representing extensive composite phenotype have been developing for at least the entire postglacial period (10 500 years). On average, 6.18–13.41% of the canopy was disturbed on individual soil units per decade. Even though the "backbone" of key events in the development of the forest ecosystem remained the same (e.g. the 1870s, 1880s and 1980s), the internal structure of disturbance history often differed among soil units; the most exceptional were Gleysols and Histosols, where important feedback from soil to trees was expected. However characteristics of treethrow dynamics as well as frequencies of stronger releases in core series significantly differed also along a gradient of terrestrial soil weathering and leaching (Haplic Cambisols – Dystric Cambisols – Entic Podzols – Albic Podzols). Results suggest the existence of several disturbance regimes within the forest controlling fine-scale pedodiversity.
Global and regional effects of land-use change on climate in 21st century simulations with interactive carbon cycle
Authors: Boysen L. R. , Brovkin V. , Arora V. K. , Cadule P. , de Noblet-Ducoudré N. , Kato E. , Pongratz J. , Gayler V.
Published: April 2014

Abstract. Biogeophysical (BGP) and biogeochemical (BGC) effects of land-use and land cover change (LULCC) are separated at the global and regional scales in new interactive CO2 simulations for the 21st century. Results from four Earth System models (ESMs) are analyzed for the future RCP8.5 scenario from simulations with and without land-use and land cover change (LULCC) contributing to the Land-Use and Climate, IDentification of robust impacts (LUCID) project. Over the period, 2006–2100, LULCC causes the atmospheric CO2 concentration to increase by 12, 22, and 66 ppm in CanESM2, MIROC-ESM, and MPI-ESM-LR, respectively. Statistically significant changes in global near-surface temperature are found in three models with a BGC-induced global mean annual warming between 0.07 and 0.23 K. BGP-induced responses are simulated by three models in areas of intense LULCC of varying sign and magnitude (between −0.47 and 0.10 K). Global land carbon losses due to LULCC are simulated by all models: 218, 57, 35 and 34 Gt C by MPI-ESM-LR, MIROC-ESM, IPSL-CM5A-LR and CanESM2, respectively. On the contrary, the CO2-fertilization effect caused by elevated atmospheric CO2 concentrations due to LULCC leads to a land carbon gain of 39 Gt C in MPI-ESM-LR and is almost negligible in the other models. A substantial part of the spread in models' responses to LULCC is attributed to the differences in implementation of LULCC (e.g. whether pastures or crops are simulated explicitly) and the simulation of specific processes. Simple idealized experiments with clear protocols for implementing LULCC in ESMs are needed to increase the understanding of model responses and the statistical significance of results, especially, when analyzing the regional-scale impacts of LULCC.
Large-scale regionalization of water table depth in peatlands optimized for greenhouse gas emission upscaling
Authors: Bechtold M. , Tiemeyer B. , Laggner A. , Leppelt T. , Frahm E. , Belting S.
Published: April 2014

Abstract. Fluxes of the three main greenhouse gases (GHG) CO2, CH4 and N2O from peat and other organic soils are strongly controlled by water table depth. Information about the spatial distribution of water level is thus a crucial input parameter when upscaling GHG emissions to large scales. Here, we investigate the potential of statistical modeling for the regionalization of water levels in organic soils when data covers only a small fraction of the peatlands of the final map. Our study area is Germany. Phreatic water level data from 53 peatlands in Germany were compiled in a new dataset comprising 1094 dip wells and 7155 years of data. For each dip well, numerous possible predictor variables were determined using nationally available data sources, which included information about land cover, ditch network, protected areas, topography, peatland characteristics and climatic boundary conditions. We applied boosted regression trees to identify dependencies between predictor variables and dip well specific long-term annual mean water level (WL) as well as a transformed form of it (WLt). The latter was obtained by assuming a hypothetical GHG transfer function and is linearly related to GHG emissions. Our results demonstrate that model calibration on WLt is superior. It increases the explained variance of the water level in the sensitive range for GHG emissions and avoids model bias in subsequent GHG upscaling. The final model explained 45% of WLt variance and was built on nine predictor variables that are based on information about land cover, peatland characteristics, drainage network, topography and climatic boundary conditions. Their individual effects on WLt and the observed parameter interactions provide insights into natural and anthropogenic boundary conditions that control water levels in organic soils. Our study also demonstrates that a large fraction of the observed WLt variance cannot be explained by nationally available predictor variables and that predictors with stronger WLt indication, relying e.g. on detailed water management maps and remote sensing products, are needed to substantially improve model predictive performance.
Extreme fluctuations of vertical velocity in the unstable atmospheric surface layer
Authors: Liu L. , Hu F. , Cheng X.-L.
Published: April 2014

Abstract. In this paper, we propose a new method to extract the extreme fluctuations of vertical velocity in the unstable atmospheric surface layer. Unlike the commonly used conditional sampling analysis, this method defines a threshold by using a systematical method and tries to reduce the artificiality in this process. It defines threshold as the position where the types of probability density functions (PDFs) of vertical velocity fluctuations begin to change character from stable distributions to truncated stable distributions. Absolute values of fluctuations greater than the threshold are considered to be extreme fluctuations. We then analyze the statistical characteristics of extracted extreme fluctuations of vertical velocity. Our results show that the amplitudes of extreme fluctuations are exponentially distributed, and the waiting times between extreme fluctuations have stretched exponential distributions. It suggests that there are statistical correlations in the time series of vertical velocity because independent time series can only have exponentially distributed waiting times. The durations of extreme fluctuations are also found to be stretched exponential distributed, while for the independent time series the distributions of durations are delta-like. Finally, the PDFs of amplitudes, waiting times and durations are all well parameterized in the context of Monin–Obukhov theory.
Politicians online – Identifying current research opportunities
Authors: Larsson Anders Olof , Svensson Jakob
Published: April 2014

For more than a decade, researchers have shown interest in how politicians make use of the Internet for a variety of purposes. Based on critical assessments of previous online political communication scholarship, this paper identifies a series of overlooked areas of research that should be of interest for researchers concerned with how politicians make use of online technologies. Specifically, three such research opportunities are introduced. First, we suggest that research should attempt to move beyond dichotomization, such as conceiving of the Internet as either bringing about revolutionary changes or having a normalizing effect. Second, while there is a considerable body of knowledge regarding the activity of politicians during election campaigns, relatively little is known about the day–to–day communicative uses of the Internet at the hands of politicians. The third section argues that as political communication research has typically focused on national or international levels of study, scholars within the field should also make efforts to contribute to our knowledge of online practices at the hands of politicians at regional and local levels — something we label as studies at the micro level. In synthesizing the literature available regarding the use of the Internet at the hands of politicians, the paper concludes suggesting routes ahead for interested scholars.
Oxalate Content of Egyptian Grown Fruits and Vegetables and Daily Common Herbs
Authors: Abdel-Moemin Aly R.
Published: April 2014

Egyptian dieticians typically rely on foreign databases to find out oxalate content of food due to unavailability of local databases. The soil, fertilizers, climate and cultivars are often very different. Therefore, the purpose of this study is to establish a local database of oxalate content in Egyptian grown fruits and vegetables and selected daily common herbs. The current study analysed the total and the soluble oxalate in 37 Egyptian grown fruits, vegetables and 9 commonly used herbs. Two methods were used for screening the Egyptian foods for oxalate concentration; the first method was AOAC 1999 and the second was enzymatic method. Total oxalate varied greatly among the vegetables examined, ranging from 4 to 917 mg/100 g F.W. Total oxalate of analysed fruits ranged from 9 to 50 mg/100 g F. W. There is a strong correlation found between the two methods used. Vegetables were classified into 4 categories; low oxalate concentration containing less than 10 mg of oxalic acid /100 g F.W., such as cabbage, courgette, cucumbers, garlic, spring onions and turnip. Moderate oxalate concentration vegetables containing 10-25 mg/100 g F. W., such as aubergine, field bean, corn, peppers and watercress. High oxalate concentration vegetables containing 26-99 mg/100g F.W., such as f?l, green beans, celery, mallow, okra and sweet potatoes. Very high oxalate concentration containing 100-900 mg/100g F.W. such as Swiss chard, molokhia, purslane and vine leaves (fresh). Extensive amounts of total oxalate (201-4014 mg/100 g D.W.) were found in daily common herbs such as caraway seed, green cardamom, cinnamon, coriander seeds, cumin, curry powder, ginger and turmeric powder.
Strontium-Metallide im Bereich des Schnitts SrIn4 – SrHg4 / Strontium Metallides along the Section SrIn4 – SrHg4
Authors: Wendorff Marco , Röhr Caroline
Published: April 2014

In a combined synthetic, X-ray single-crystal and bond-theoretical study the phase widths of SrIn4 and the related Sr3In11 upon a sucessive substitution of indium against the more electronpoor, more electronegative and only slightly smaller element mercury have been studied. Along the 1 : 4 section Sr(In1-xHgx)4 the monoclinic structure of SrIn4 ( EuIn4-type structure) is stable up to x =0.14(1) ( SrIn3.44Hg0.56: monoclinic, C2/m, a = 1208.3(6), b = 502:5(2), c = 997.7(6) pm, b = 115.16(3)°, Z = 4, R1 = 0.0324). Further increased mercury content results in a distinct stability region of the very common BaAl4 structure type (tetragonal, I4=mmm, Z = 2), which starts at x =0.241(7) ( SrIn3.04Hg0.96: a = 4694(2), c = 1246.4(7) pm, R1 = 0.0374) and reaches up to the fully ordered compound SrIn2Hg2 (x =0.5: a = 456.4(3), c = 1273.5(11) pm, R1 = 0.0572). Unexpectedly, in the small composition range from x=0.68(1) to 0.758(6) ( SrIn1.16Hg2.84: a=1178.5(4), b = 495.20(12), c = 1016.8(4) pm, b = 119.67(2)°, R1 = 0.0542; SrIn0.97Hg3.03: a = 1167.30(4), b = 495.32(2), c = 1018.50(3) pm, b = 119.657(2)°, R1 = 0.0426) the EuIn4 structure type exhibits a further small stability range. The structures of the two slightly different In- and Hg-rich variants of the EuIn4 type are described and compared, indicating the similarities to the KHg2 (layers of folded In=Hg ladders) and the BaAl4 structure type (flat square pyramids) as well as to the structure of elemental mercury (rhombohedra). From samples of an intermediate In=Hg ratio (e. g. x =0.55), the new 1 : 3 compound SrIn1.2Hg1.8 (monoclinic, C2=m, a = 1168.5(13), b = 497.0(4), c = 1471(2) pm, b = 92.07(10)°, Z = 8, R1 = 0.0818) is formed. It crystallizes in a new structure type, which - according to the compound’s composition - can be described as a stacking variant of the EuIn4 and the KHg2 structure type. In contrast to the wide stability ranges of the 1 : 4 compounds, only a very small substitution of In ranging up to only 6% of Hg is possible in the binary indide Sr3In11 ( Sr3In10.32(8)Hg0.68(8): La3Al11 structure type, orthorhombic, Immm, a = 487:6(2), b = 1140.2(5), c = 1421.1(7) pm, Z = 2, R1 = 0.0703). The formation, stability ranges and the In=Hg ‘coloring’ of the polyanions are discussed for all compounds taking into account geometric (radius ratios, molar volumes, Sr coordination polyhedra etc.) and electronic aspects, which have been evaluated using FP-LAPW band structure calculations.
Structure and Properties of 2,3,3,3-Tetrafluoropropene (HFO-1234yf)
Authors: Feller Michael , Lux Karin , Hohenstein Christian , Kornath Andreas
Published: April 2014

The novel refrigerant 2,3,3,3-tetrafluoropropene (HFO-1234yf) is discussed as a replacement for 1,1,1,2-tetrafluoroethane (R-134a) due to its low global warming potential. Although it may therefore have great potential for use on a large scale, no structural data and only a fewvibrational data of the compound are known.We describe low-temperature X-ray structure analysis, vibrational spectra and combustion properties of 2,3,3,3-tetrafluoropropene. The experimental data are compared with the results of theoretical calculations. Furthermore the basic combustion properties have been investigated.
Four Achnanthidium species (Bacillariophyta) formerly identified as Achnanthidium minutissimum from the Antarctic Region
Authors: Van de Vijver Bart , Kopalová Kateřina
Published: April 2014

Four taxa belonging to the complex of species around Achnanthidium minutissimum were found during the ongoing taxonomic revision of the Antarctic freshwater and limno-terrestrial diatom flora. Two taxa were previously described as Achnanthidium lailae and A. sieminskae. Two others were formerly identified as A. minutissimum but detailed light and scanning electron microscopical observations revealed sufficient morphological differences compared to the type of A. minutissimum, to justify their separation and description as new taxa: Achnanthidium indistinctum and A. maritimo-antarcticum. The morphology and ecology of all four taxa are discussed comparing the species with morphologically similar taxa. The biogeographical consequences of the splitting of the former A. minutissimum complex in the Antarctic Region are discussed.
Parâmetros genéticos para a conservação de Hymenaea courbaril L. na Amazônia sul-ocidental
Authors: Silva Susana Maria Melo , Martins Karina , Mesquita Antônio Gilson Gomes , Wadt Lucia Helena de Oliveira
Published: April 2014

http://dx.doi.org/10.5902/1980509813326A perda de diversidade em regiões tropicais tem sido pauta em diversas discussões governamentais e não governamentais, com foco principalmente na fragmentação e destruição de ecossistemas naturais. No entanto, tomadas de decisões sobre a conservação de recursos genéticos precisam ser pautadas em parâmetros genéticos populacionais, especialmente para as espécies com interesse econômico que são alvo de maior interferência humana. Este trabalho teve como objetivo definir e avaliar parâmetros genéticos para a conservação de populações de jatobá (Hymenaea courbaril) na região sul-ocidental da Amazônia brasileira. A espécie é uma das que possuem madeira mais valiosa e é uma das mais intensamente exploradas na Amazônia brasileira. O estudo foi realizado em três áreas de florestas preparadas para a exploração madeireira, segundo plano de manejo sustentável. Calculou-se, com uso de oito locos de marcadores microssatélites, a diversidade genética, os estimadores para a conservação da espécie e a divergência entre as populações. As populações com menor densidade populacional (< 0,08 ind.ha-1) apresentaram maior diversidade genética e índice de fixação elevado. A população com maior densidade populacional (0,25 ind.ha-1) foi a que apresentou menor diversidade genética e ausência de endogamia. A Área Mínima Viável para conservação da espécie foi compatível com a realidade do local de estudo, com uma ressalva de uma das populações onde há necessidade de uma área muito maior em relação às demais. A divergência genética foi elevada (G’ST = 0,344) e as populações foram classificadas como Unidades Independentes para o Manejo.
Comparação técnica e econômica entre harvesters de pneus e com máquina base de esteiras
Authors: Seixas Fernando , Batista João Luís Ferreira
Published: April 2014

http://dx.doi.org/10.5902/1980509813335Uma opção muito empregada na colheita de árvores é a adaptação de escavadoras de esteiras, como máquina base, equipadas com cabeçote processador, sendo uma opção às máquinas colhedoras tipicamente florestais. Sua utilização baseia-se principalmente no custo menor de aquisição e a existência de modelos fabricados no país, facilitando a assistência técnica e a compra de peças e manutenção. Argumentos contrários referem-se ao custo elevado de manutenção das esteiras e uma maior restrição à operação em terrenos acidentados, em comparação com máquinas de pneus. O objetivo deste trabalho foi comparar, quanto a aspectos técnicos e econômicos, a utilização, na operação de corte de árvores em terreno plano, de modelos de harvesters de pneus com escavadoras de esteiras adaptadas para uso florestal. O maior custo hora dos modelos de harvesters de pneus, utilizados nas condições deste estudo, favoreceu a indicação do emprego de harvesters com máquina base de esteiras na operação de corte raso de árvores em povoamentos localizados em terrenos planos, com os dois modelos de máquinas apresentando produtividades muito próximas em condições de povoamentos florestais teoricamente similares.
Efeito do desbaste nas rachaduras de topo das toras de Eucalyptus grandis W. Hill ex Maiden
Authors: Trevisan Rômulo , Haselein Clovis Roberto , Santini Elio José , Denardi Luciano , Gatto Darci Alberto
Published: April 2014

http://dx.doi.org/10.5902/1980509813336O estudo teve como objetivo avaliar o efeito do desbaste nas rachaduras de topo das toras de Eucalyptus grandis aos 18 anos de idade. Para tanto, foi analisado um experimento situado próximo ao litoral do Rio Grande do Sul, instalado em delineamento blocos ao acaso com quatro repetições. Os sete tratamentos foram definidos devido ao número de desbastes aplicados e variaram de zero até seis intervenções. As árvores foram selecionadas, em cada tratamento, com base no diâmetro dominante de Assmann e no diâmetro da árvore central, sendo denominadas de árvores dominantes e centrais, respectivamente. Após o abate foram selecionadas as toras localizadas entre as posições do DAP (diâmetro a altura do peito) e 25%; 25% e 50%; 50% e 75%; 75% e 100% da altura comercial para o estudo das rachaduras de topo. Os resultados indicaram que o índice médio de rachadura de topo das árvores dominantes e centrais foi maior na segunda tora amostrada, evidenciando que a toragem das árvores deve ser realizada em conjunto com técnicas que minimizem as tensões de crescimento, principalmente quando o seccionamento for realizado próximo à metade da altura comercial. O desbaste induziu a variação do índice médio de rachadura de topo das toras, tanto nas árvores dominantes quanto nas centrais; porém, não foi verificada uma tendência clara positiva ou negativa, podendo-se concluir que alterações na taxa de crescimento não afetaram esse parâmetro de maneira uniforme.
Efeito da inversão no tratamento de moirões submetidos ao método de substituição da seiva
Authors: Paes Juarez Benigno , Santos Gerlanda Caetano dos , Melo Rafael Rodolfo de , Lima Carlos Roberto de , Sobrinho Wlademir Nicolau
Published: April 2014

http://dx.doi.org/10.5902/1980509813338O objetivo da pesquisa foi avaliar o efeito da inversão de moirões de algaroba (Prosopis juliflora) e de leucena (Leucaena leucocephala), na solução preservativa, na distribuição, penetração e retenção do borato de cobre cromatado (CCB) aplicado pelo método de substituição da seiva. A algaroba foi coletada na Empresa Brasileira de Pesquisa Agropecuária (EMBRAPA) e a leucena no Campus da Universidade Federal de Campina Grande, em Patos - PB. Foram colhidas árvores com DAP entre 6,0 a 12,0 cm. Retiraram-se dois discos de 2,0 cm de espessura no topo e base das peças. Os discos externos foram descartados e os internos empregados nas determinações das características das madeiras, ficando as peças com 2,0 m. Empregou-se uma solução de 2% de ingredientes ativos de CCB. Foram tratadas 10 peças de cada espécie, tendo cinco delas permanecido dispostas na solução durante 8 dias e cinco tiveram seus topos invertidos após o sexto dia de tratamento. As peças foram secas ao ar, retiraram-se discos de 2,0 cm de espessura para a determinação da penetração (cinco posições nas peças) e para a retenção do CCB (três posições). Os valores das características das madeiras indicaram que as peças eram homogêneas. A absorção da solução foi de 19,9 litros (algaroba) e de 17,0 litros (leucena), acarretando em uma retenção nominal de CCB de 7,72 e 5,34 kg de ingredientes ativos (i.a.)/m3, respectivamente. De maneira geral, a inversão das peças na solução preservativa é recomendável, por proporcionar uma melhor distribuição, penetração e retenção do CCB ao longo da peça tratada.
Problem: Integers: Draw or Discard! Game
Authors: Bofferding Laura , Wessman-Enzinger Nicole
Published: April 2014

This department publishes brief news articles, announcements and guest editorials on current mathematics education issues that stimulate the interest of TCM readers and cause them to think about an issue or consider a specific viewpoint about some aspect of mathematics education.
Solutions: The Healthy Vending Machine
Authors: Stark Walter
Published: April 2014

The April problem scenario from last year requires students to read and interpret data from a table. All classroom teachers are invited to showcase students' in-depth thinking and work on problems previously published in Teaching Children Mathematics.
Assessing Basic Facts Fluency
Authors: Kling Gina , Bay-Williams Jennifer M.
Published: April 2014

Have you had it with timed tests, which present a number of concerns and limitations? Try a variety of alternative assessments from this sampling that allows teachers to accurately and appropriately measure childre's fact fluency.
Is It Counting, or Is It Adding?
Authors: Eisenhardt Sara , Fisher Molly H. , Thomas Jonathan , Schack Edna O. , Tassell Janet , Yoder Margaret
Published: April 2014

Appreciate the complexity of counting and adding skills by viewing them through the lens of an early numeracy progression.
Celebrating Earth Day with sustainability
Authors: Sibley Amanda , Kurz Terri L.
Published: April 2014

Earth Day presents an annual opportunity to discuss sustainability with students. This article describes a six-week unit that integrated sustainability and mathematics at the intermediate elementary school level. Students explored a topic and identified solutions that would support preserving resources for the betterment of our planet. The iSTEM (Integrating Science Technology Engineering in Mathematics) authors share ideas and activities that stimulate student interest in the integrated fields STEM in K—grade 6 classrooms.
Relationship Between Vitamin D and Cardio-Metabolic Biomarkers Among Saudi Postmenopausal Women
Authors: Alissa Eman M. , Alnahdi Wafa A. , Alama Nabeel , Ferns Gordon A.
Published: April 2014

Vitamin D deficiency is prevalent worldwide, and in Saudi Arabia in particular. There is growing evidence that hypovitaminosis D is involved in the pathogenesis of cardiovascular diseases. We determined concentrations of serum 25 hydroxy 25(OH) vitamin D in relation to several metabolic biomarkers including total cholesterol (TC), low density lipoprotein-cholesterol (LDL-C), high density lipoprotein-cholesterol, triglycerides (TG), atherogenic index (AI), glucose, C-reactive protein (CRP), adiposity, and blood pressure in a cross-sectional analysis in 300 Saudi postmenopausal women. Participants completed a detailed questionnaire and fasting blood samples were collected. Vitamin D deficiency was common, affecting 89% of individuals. Higher serum 25(OH) vitamin D levels were consistently found among subjects with no prevalent cardiovascular risk factors (p>0.05) except for those subjects with serum CRP level ≥3mg/dl, HDL-C <1.04mmol/L, AI≥5, exercising ≥3times/week, and those with 4 or more pregnancies. Hypovitaminosis D was inversely correlated with DBP (r=-0.118, p=0.042), TC (r=-0.165, p=0.004), TG (r=-0.119, p=0.040), LDL-C (r=-0.138, p=0.017), AI (r=-0.125, p=0.031), and veiling type (r=-0.127, p=0.028). No significant impact of hypovitaminosis D on CRP, levels of which were similar among vitamin D sufficient and deficient subjects. However, hypovitaminosis D was significantly related to dyslipidemia and diastolic blood pressure in a group of Saudi postmenopausal women.
The Terminographical Process: Phases and Dimensions
Authors: Remígio Ana Rita
Published: April 2014

A proposal for segmentation and characterisation of the terminographical process, based on Gouadec’s model for translation, is presented in this paper. It comes as a result of a systematisation and comparative analysis of the various existing characterisations of the terminographical process, in an attempt – that has proven to be unfruitful – to identify the one, or a combination of different ones, which would meet the specific needs to build a resource targeted at a non-specialist public. The terminographical process is thus organised in three phases (pre-terminography, terminography, and post-terminography), and comprises three dimensions of analysis (conceptual, communicative, and textual). Broadly speaking, in pre-terminography, a preparatory piece of research is carried out (special subject field familiarisation, communicative contexts identification, and building of specialized corpora), a step which is essential to the next phase (terminography), in which a terminological database is built and populated. The last phase (post-terminography) comprises efforts aimed at the industrial application of the resource, as well as underscoring the need for its continual update. This methodology also takes into account the three dimensions of terms (conceptual, communicative and textual) which are applied and adopted in the process of termbase creation itself.
La réadaptation cardiaque en contexte de défavorisation matérielle et sociale1
Authors: Bergeron Cindy , Dumas Alex , Savage Mathieu
Published: April 2014

Les effets bénéfiques des programmes de réadaptation cardiaque ont été largement documentés. Par contre, peu d’études se sont penchées sur la faible participation des populations moins bien nanties. En employant l’approche socioculturelle de Pierre Bourdieu, cette étude qualitative contribue à élargir la base des connaissances à l’égard des pratiques de réadaptation cardiaque d’hommes de milieux socio-économiquement défavorisés. Des entrevues semi-structurées ont été effectuées auprès de 22 hommes francophones (âge moyen : 51,7 ans) de l’Outaouais urbain et ayant subi un accident cardiovasculaire. Les résultats suggèrent que les conditions de défavorisation façonnent un rapport au corps incompatible avec les normes de santé publique. Deux thèmes principaux sont développés : (a) les faibles dispositions à adopter des pratiques préventives en santé et (b) les faibles dispositions à participer à un programme de réadaptation cardiaque.