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Sample records for patterns reflect nitrogen

  1. Nitrogen vertical distribution by canopy reflectance spectrum in winter wheat

    International Nuclear Information System (INIS)

    Huang, W J; Yang, Q Y; Peng, D L; Huang, L S; Zhang, D Y; Yang, G J

    2014-01-01

    Nitrogen is a key factor for plant photosynthesis, ecosystem productivity and leaf respiration. Under the condition of nitrogen deficiency, the crop shows the nitrogen deficiency symptoms in the bottom leaves, while excessive nitrogen will affect the upper layer leaves first. Thus, timely measurement of vertical distribution of foliage nitrogen content is critical for growth diagnosis, crop management and reducing environmental impact. This study presents a method using bi-directional reflectance difference function (BRDF) data to invert foliage nitrogen vertical distribution. We developed upper-layer nitrogen inversion index (ULNI), middle-layer nitrogen inversion index (MLNI) and bottom-layer nitrogen inversion index (BLNI) to reflect foliage nitrogen inversion at upper layer, middle layer and bottom layer, respectively. Both ULNI and MLNI were made by the value of the ratio of Modified Chlorophyll Absorption Ration Index to the second Modified Triangular Vegetation Index (MCARI/MTVI2) referred to as canopy nitrogen inversion index (CNII) in this study at ±40° and ±50°, and at ±30° and ±40° view angles, respectively. The BLNI was composed by the value of nitrogen reflectance index (NRI) at ±20° and ±30° view angles. These results suggest that it is feasible to measure foliage nitrogen vertical-layer distribution in a large scale by remote sensing

  2. Soil Nitrogen Availability Is Reflected in the Bacterial Pathway1

    Institute of Scientific and Technical Information of China (English)

    V.KRIVTSOV; B.S.GRIFFITHS; K.LIDDELL; A.GARSIDE; R.SALMOND; T.BEZGINOVA; J.THOMPSON

    2011-01-01

    Measurements of concentrations of easily extractable soil nitrogen (N) were carried out on samples collected at the Heron Wood Reserve, Scotland, concurrently with investigations of N associated with total microbial biomass and the abundances of bacteria,fungi, and invertebrates. Soil biota at the studied site appeared to be limited by N. There was a remarkable difference between the ambient (i.e., easily extractable N) and biomass nitrogen. The abundance data of bacteria, protozoa and nematodes significantly negatively correlated with ambient N but showed positive correlations with the total microbial N content. There were, however,remarkable differences between the correlation patterns exhibited by the fungal and the bacterial pathways, as fungi did not show any correlations with chemical variables. These differences should be taken into account whilst interpreting biological interactions both at this important site and elsewhere.

  3. Leaf reflectance-nitrogen-chlorophyll relations among three south Texas woody rangeland plant species

    Science.gov (United States)

    Gausman, H. W.; Everitt, J. H.; Escobar, D. E. (Principal Investigator)

    1982-01-01

    Annual variations in the nitrogen-chlorophyll leaf reflectance of hackberry, honey mesquite and live oak in south Texas, were compared. In spring, leaf reflectance at the 0.55 m wavelength and nitrogen (N) concentration was high but leaf chlorophyll (chl) concentrations were low. In summer, leaf reflectance and N-concentration were low but lead chl concentrations were high. Linear correlations for both spring and summer of leaf reflectance with N and chl concentration or deviations from linear regression were not statistically significant.

  4. Seasonal patterns of periphyton nitrogen fixation in calcareous wetlands

    Science.gov (United States)

    Liao, X.; Inglett, P.

    2011-12-01

    Periphyton mats are an ecologically important component of the Everglades ecosystem and plays various vital ecological functions. However, nitrogen fixation of periphyton, has received little attention throughout much of the Everglades system. The objective of this study was to characterize the seasonal pattern of periphyton N2 fixation in the Hole-in-the-Donut (HID) of Florida Everglades, where farmed marl prairie wetlands have been restored through complete soil removal (CSR) to reduce nutrient levels. Two restored areas (i.e., cleared in 2000 and 2003) and a reference (natural and unfarmed) marl prairie wetland sites were selected in the HID. Seven times of sampling were performed across the wet and dry season during the 2010 and 2011. The annual fixed nitrogen was approximately 0.4gN m-2 yr-1 in the restored sites which was higher in the reference site (~0.2gN m-2 yr-1). All the three sites showed similar seasonal patterns of N2 fixation that is higher values were observed in the wet season; but the peak value was one month later in reference sits (i.e., September) comparing to the restored areas (i.e., July). The peak of periphyton AR rates in the 2000- and 2003-restored areas appeared in July (i.e., wet season) within the range of 20-79 nmols g-1dw h-1 and 31-53nmols g-1dw h-1, respectively. In contrast, the peak of reference site was observed in September with the range of 2-5 nmols g-1dw h-1. Stable N isotopic ratios (i.e., δ15N) also varied with time but didn't show consistent seasonal pattern as nitrogen fixation. N2 fixation positively correlated with periphyton total phosphorus (TP) and negatively correlated with total nitrogen and phosphorus molar ratios (TN:TP), indicating that N2 fixation would be a indicator of nutrient limitation. In general, δ15N was negatively correlated with nitrogenase activity but the correlation became weakened in the wet season, especially in the flooded July and September, which would be explained by other environmental

  5. Attachment Patterns and Reflective Functioning in traumatised refugees

    DEFF Research Database (Denmark)

    Riber, Karin

    2013-01-01

    psychotherapy research has shown is central to change and effect. Aims: 1) To examine attachment patterns and reflective functioning in traumatised refugees with PTSD, and 2) shed light on their significance to therapeutic alliance and treatment effect. Methods: All Arabic speaking patients in the study......Traumatized refugees have often suffered severe, prolonged, repeated traumas and pose a challenge to treatment. Attachment patterns and level of mentalizing seem to work as protection mechanisms in traumatizing events and to be important for positively utilizing the therapeutic alliance which...

  6. Optical patterning of trapped charge in nitrogen-doped diamond

    Science.gov (United States)

    Jayakumar, Harishankar; Henshaw, Jacob; Dhomkar, Siddharth; Pagliero, Daniela; Laraoui, Abdelghani; Manson, Neil B.; Albu, Remus; Doherty, Marcus W.; Meriles, Carlos A.

    2016-08-01

    The nitrogen-vacancy (NV) centre in diamond is emerging as a promising platform for solid-state quantum information processing and nanoscale metrology. Of interest in these applications is the manipulation of the NV charge, which can be attained by optical excitation. Here, we use two-colour optical microscopy to investigate the dynamics of NV photo-ionization, charge diffusion and trapping in type-1b diamond. We combine fixed-point laser excitation and scanning fluorescence imaging to locally alter the concentration of negatively charged NVs, and to subsequently probe the corresponding redistribution of charge. We uncover the formation of spatial patterns of trapped charge, which we qualitatively reproduce via a model of the interplay between photo-excited carriers and atomic defects. Further, by using the NV as a probe, we map the relative fraction of positively charged nitrogen on localized optical excitation. These observations may prove important to transporting quantum information between NVs or to developing three-dimensional, charge-based memories.

  7. Fusing corn nitrogen recommendation tools for an improved canopy reflectance sensor performance

    Science.gov (United States)

    Nitrogen (N) rate recommendation tools are utilized to help producers maximize corn grain yield production. Many of these tools provide recommendations at field scales but often fail when corn N requirements are variable across the field. Canopy reflectance sensors are capable of capturing within-fi...

  8. Security authentication using the reflective glass pattern imaging effect.

    Science.gov (United States)

    Zhu, Ji Cheng; Shen, Su; Wu, Jian Hong

    2015-11-01

    The reflective glass pattern imaging effect is investigated experimentally for the utility in forming a synthetic 3D image as a security authentication device in this Letter. An array of homogeneously randomly distributed reflective elements and a corresponding micropattern array are integrated onto a thin layer of polyester film aiming to create a vivid image floating over a substrate surface, which can be clearly visible to the naked eye. By using the reflective-type configuration, the micro-optic system can be realized on a thinner substrate and is immune to external stain due to its flat working plane. A novel gravure-like doctor blading technique can realize a resolution up to 12,000 dpi and a stringent 2D alignment requirement should be imposed. Such devices can find applications in document security and banknotes or other valuable items to protect them against forgery.

  9. Linking Global Patterns of Nitrogen Resorption with Nitrogen Mineralization During Litter Decomposition

    Science.gov (United States)

    Deng, M.; Liu, L.; Jiang, L.

    2017-12-01

    The nitrogen (N) cycle in terrestrial ecosystems is strongly influenced by resorption prior to litter fall and by mineralization after litter fall. Although both resorption and mineralization make N available to plants and are influenced by climate, their linkage in a changing environment remains largely unknown. Here, we show that, at the global scale, increasing N resorption efficiency has a negative effect on the N mineralization rate. With increasing temperature and precipitation, the increasing rate of the N cycle is closely related to the shift from the more conservative resorption pathway to an acquiring mineralization pathway. Furthermore, systems with faster N-cycle rates support plants with higher foliar N:P ratios and microbes with lower fungi:bacteria ratios. We highlight the importance of considering the geographic pattern and the dynamic interaction between N resorption and N mineralization, which should be incorporated into earth-system models to improve the simulation of nutrient constraints on ecosystem productivity.

  10. Global patterns of foliar nitrogen isotopes and their relationships with climate, mycorrhizal fungi, foliar nutrient concentrations, and nitrogen availability

    Science.gov (United States)

    Joseph M. Craine; Andrew J. Elmore; Marcos P. M. Aidar; Mercedes Bustamante; Todd E. Dawson; Erik A. Hobbie; Ansgar Kahmen; Michelle C. Mack; Kendra K. McLauchlan; Anders Michelsen; Gabriela Nardoto; Linda H. Pardo; Josep Penuelas; Peter B. Reich; Edward A.G. Schuur; William D. Stock; Pamela H. Templer; Ross A. Virginia; Jeffrey M. Welker; Ian J. Wright

    2009-01-01

    Ratios of nitrogen (N) isotopes in leaves could elucidate underlying patterns of N cycling across ecological gradients. To better understand global-scale patterns of N cycling, we compiled data on foliar N isotope ratios, foliar N concentrations, mycorrhizal type and climate for over 11 000 plants worldwide. Global-scale comparisons of other components of the N cycle...

  11. Global patterns of foliar nitrogen isotopes and their relationships with climate, mycorrhizal fungi, foliar nutrient concentrations, and nitrogen availability

    DEFF Research Database (Denmark)

    Craine, J M; Elmore, A J; Aidar, M P M

    2009-01-01

    Ratios of nitrogen (N) isotopes in leaves could elucidate underlying patterns of N cycling across ecological gradients. To better understand global-scale patterns of N cycling, we compiled data on foliar N isotope ratios (d15N), foliar N concentrations, mycorrhizal type and climate for over 11 00...

  12. Diet-animal fractionation of nitrogen stable isotopes reflects the efficiency of nitrogen assimilation in ruminants.

    Science.gov (United States)

    Cantalapiedra-Hijar, G; Ortigues-Marty, I; Sepchat, B; Agabriel, J; Huneau, J F; Fouillet, H

    2015-04-14

    The natural abundance of ¹⁵N in animal proteins (δ¹⁵Nanimal) is greater than that in the diet consumed by the animals (δ¹⁵Ndiet), with a discrimination factor (Δ¹⁵N = δ¹⁵Nanimal - δ¹⁵Ndiet) that is known to vary according to nutritional conditions. The objectives of the present study were to test the hypothesis that Δ¹⁵N variations depend on the efficiency of nitrogen utilisation (ENU) in growing beef cattle, and to identify some of the physiological mechanisms responsible for this N isotopic fractionation in ruminants. Thus, we performed the regression of the Δ¹⁵N of plasma proteins obtained from thirty-five finishing beef cattle fed standard and non-conventional diets against different feed efficiency indices, including ENU. We also performed the regression of the Δ¹⁵N of different ruminant N pools (plasma and milk proteins, urine and faeces) against different splanchnic N fluxes obtained from multi-catheterised lactating dairy cows. The Δ¹⁵N of plasma proteins was negatively correlated with feed efficiency indices in beef cattle, especially ENU (body protein gain/N intake) and efficiency of metabolisable protein (MP) utilisation (body protein gain/MP intake). Although Δ¹⁵N obtained from different N pools in dairy cows were all negatively correlated with ENU, the highest correlation was found when Δ¹⁵N was calculated from plasma proteins. Δ¹⁵N showed no correlation with urea-N recycling or rumen NH₃ absorption, but exhibited a strong correlation with liver urea synthesis and splanchnic amino acid metabolism, which points to a dominant role of splanchnic tissues in the present N isotopic fractionation study.

  13. Quantification of Reflection Patterns in Ground-Penetrating Radar Data

    Science.gov (United States)

    Moysey, S.; Knight, R. J.; Jol, H. M.; Allen-King, R. M.; Gaylord, D. R.

    2005-12-01

    Radar facies analysis provides a way of interpreting the large-scale structure of the subsurface from ground-penetrating radar (GPR) data. Radar facies are often distinguished from each other by the presence of patterns, such as flat-lying, dipping, or chaotic reflections, in different regions of a radar image. When these patterns can be associated with radar facies in a repeated and predictable manner we refer to them as `radar textures'. While it is often possible to qualitatively differentiate between radar textures visually, pattern recognition tools, like neural networks, require a quantitative measure to discriminate between them. We investigate whether currently available tools, such as instantaneous attributes or metrics adapted from standard texture analysis techniques, can be used to improve the classification of radar facies. To this end, we use a neural network to perform cross-validation tests that assess the efficacy of different textural measures for classifying radar facies in GPR data collected from the William River delta, Saskatchewan, Canada. We found that the highest classification accuracies (>93%) were obtained for measures of texture that preserve information about the spatial arrangement of reflections in the radar image, e.g., spatial covariance. Lower accuracy (87%) was obtained for classifications based directly on windows of amplitude data extracted from the radar image. Measures that did not account for the spatial arrangement of reflections in the image, e.g., instantaneous attributes and amplitude variance, yielded classification accuracies of less than 65%. Optimal classifications were obtained for textural measures that extracted sufficient information from the radar data to discriminate between radar facies but were insensitive to other facies specific characteristics. For example, the rotationally invariant Fourier-Mellin transform delivered better classification results than the spatial covariance because dip angle of the

  14. Autofluorescence and diffuse reflectance patterns in cervical spectroscopy

    Science.gov (United States)

    Marin, Nena Maribel

    Fluorescence and diffuse reflectance spectroscopy are two new optical technologies, which have shown promise to aid in the real time, non-invasive identification of cancers and precancers. Spectral patterns carry a fingerprint of scattering, absorption and fluorescence properties in tissue. Scattering, absorption and fluorescence in tissue are directly affected by biological features that are diagnostically significant, such as nuclear size, micro-vessel density, volume fraction of collagen fibers, tissue oxygenation and cell metabolism. Thus, analysis of spectral patterns can unlock a wealth of information directly related with the onset and progression of disease. Data from a Phase II clinical trial to assess the technical efficacy of fluorescence and diffuse reflectance spectroscopy acquired from 850 women at three clinical locations with two research grade optical devices is calibrated and analyzed. Tools to process and standardize spectra so that data from multiple spectrometers can be combined and analyzed are presented. Methodologies for calibration and quality assurance of optical systems are established to simplify design issues and ensure validity of data for future clinical trials. Empirically based algorithms, using multivariate statistical approaches are applied to spectra and evaluated as a clinical diagnostic tool. Physically based algorithms, using mathematical models of light propagation in tissue are presented. The presented mathematical model combines a diffusion theory in P3 approximation reflectance model and a 2-layer fluorescence model using exponential attenuation and diffusion theory. The resulting adjoint fluorescence and reflectance model extracts twelve optical properties characterizing fluorescence efficiency of cervical epithelium and stroma fluorophores, stromal hemoglobin and collagen absorption, oxygen saturation, and stromal scattering strength and shape. Validations with Monte Carlo simulations show that adjoint model extracted

  15. Patterns and controls on nitrogen cycling of biological soil crusts

    Science.gov (United States)

    Barger, Nichole N.; Zaady, Eli; Weber, Bettina; Garcia-Pichel, Ferran; Belnap, Jayne

    2016-01-01

    Biocrusts play a significant role in the nitrogen [N ] cycle within arid and semi-arid ecosystems, as they contribute major N inputs via biological fixation and dust capture, harbor internal N transformation processes, and direct N losses via N dissolved, gaseous and erosional loss processes (Fig. 1). Because soil N availability in arid and semi-arid ecosystems is generally low and may limit net primary production (NPP), especially during periods when adequate water is available, understanding the mechanisms and controls of N input and loss pathways in biocrusts is critically important to our broader understanding of N cycling in dryland environments. In particular, N cycling by biocrusts likely regulates short-term soil N availability to support vascular plant growth, as well as long-term N accumulation and maintenance of soil fertility. In this chapter, we review the influence of biocrust nutrient input, internal cycling, and loss pathways across a range of biomes. We examine linkages between N fixation capabilities of biocrust organisms and spatio-temporal patterns of soil N availability that may influence the longer-term productivity of dryland ecosystems. Lastly, biocrust influence on N loss pathways such as N gas loss, leakage of N compounds from biocrusts, and transfer in wind and water erosion are important to understand the maintenance of dryland soil fertility over longer time scales. Although great strides have been made in understanding the influence of biocrusts on ecosystem N cycling, there are important knowledge gaps in our understanding of the influence of biocrusts on ecosystem N cycling that should be the focus of future studies. Because work on the interaction of N cycling and biocrusts was reviewed in Belnap and Lange (2003), this chapter will focus primarily on research findings that have emerged over the last 15 years (2000-2015).

  16. Do subjective assessments of running patterns reflect objective parameters?

    Science.gov (United States)

    Lussiana, Thibault; Gindre, Cyrille; Mourot, Laurent; Hébert-Losier, Kim

    2017-08-01

    Running patterns are often categorized into subgroups according to common features before data analysis and interpretation. The Volodalen ® method is a simple field-based tool used to classify runners into aerial or terrestrial using a 5-item subjective rating scale. We aimed to validate the Volodalen ® method by quantifying the relationship between its subjective scores and 3D biomechanical measures. Fifty-four runners ran 30 s on a treadmill at 10, 12, 14, 16, and 18 km h -1 while their kinematics were assessed subjectively using the Volodalen ® method and objectively using 3D motion capture. For each runner and speed, two researchers scored the five Volodalen ® items on a 1-to-5 scale, which addressed vertical oscillation, upper-body motion, pelvis and foot position at ground contact, and footstrike pattern. Seven 3D biomechanical parameters reflecting the subjective items were also collected and correlated to the subjective scores. Twenty-eight runners were classified as aerial and 26 as terrestrial. Runner classification did not change with speed, but the relative contribution of the biomechanical parameters to the subjective classification was speed dependent. The magnitude of correlations between subjective and objective measures ranged from trivial to very large. Five of the seven objective parameters significantly differed between aerial and terrestrial runners, and these parameters demonstrated the strongest correlations to the subjective scores. Our results support the validity of the Volodalen ® method, whereby the visual appreciation of running gait reflected quantifiable objective parameters. Two minor modifications to the method are proposed to simplify its use and improve agreement between subjective and objective measures.

  17. Nitrogen transformations in wetlands: Effects of water flow patterns

    Energy Technology Data Exchange (ETDEWEB)

    Davidsson, T.

    1997-11-01

    In this thesis, I have studied nitrogen turnover processes in water meadows. A water meadow is a wetland where water infiltrates through the soil of a grassland field. It is hypothesized that infiltration of water through the soil matrix promotes nutrient transformations compared to surface flow of water, by increasing the contact between water, nutrients, soil organic matter and bacteria. I have studied how the balance between nitrogen removal (denitrification, assimilative uptake, adsorption) and release (mineralization, desorption) processes are affected by water flow characteristics. Mass balance studies and direct denitrification measurements at two field sites showed that, although denitrification was high, net nitrogen removal in the water meadows was poor. This was due to release of ammonium and dissolved organic nitrogen (DON) from the soils. In laboratory studies, using {sup 15}N isotope techniques, I have shown that nitrogen turnover is considerably affected by hydrological conditions and by soil type. Infiltration increased virtually all the nitrogen processes, due to deeper penetration of nitrate and oxygen, and extended zones of turnover processes. On the contrary, soils and sediments with surface water flow, diffusion is the main transfer mechanism. The relation between release and removal processes sometimes resulted in shifts towards net nitrogen production. This occurred in infiltration treatments when ammonium efflux was high in relation to denitrification. It was concluded that ammonium and DON was of soil origin and hence not a product of dissimilatory nitrate reduction to ammonium. Both denitrification potential and mineralization rates were higher in peaty than in sandy soil. Vertical or horizontal subsurface flow is substantial in many wetland types, such as riparian zones, tidal salt marshes, fens, root-zone systems and water meadows. Moreover, any environment where aquatic and terrestrial ecosystems meet, and where water level fluctuates

  18. Optical Reflectance and Fluorescence for Detecting Nitrogen Needs in Zea mays L.

    Science.gov (United States)

    McMurtrey, J. E.; Middleton, E. M.; Corp. L. A.; Campbell, P. K. Entcheva; Butcher, L. M.; Daughtry, C. S. T.

    2003-01-01

    Nitrogen (N) status in field grown corn (Zea mays L.) was assessed using spectral techniques. Passive reflectance remote sensing and, both passive and active fluorescence sensing methods were investigated. Reflectance and fluorescence methods are reported to detect changes in the primary plant pigments (chlorophylls a and b; carotenoids) in higher plant species. As a general rule, foliar chlorophyll a (Chl a) and chlorophyll b (Chl b) usually exist in approx.3:l ratio. In plants under stress, Chl b content is affected before Chl a reductions occur. For reflectance, a version of the chlorophyll absorption in reflectance index (CARI) method was tested with narrow bands from the Airborne Imaging Spectroradiometer for Applications (ASIA). CARI minimizes the effects of soil background on the signal from green canopies. A modified CARI (MCARI) was used to track total Chl a levels in the red dip of the spectrum from the corn canopy. A second MCARI was used to track the auxiliary plant pigments (Chl b and the carotenoids) in the yellow/orange/red edge part of the reflectance spectrum. The difference between these two MCARI indices detected variations in N levels across the field plot canopies using ASIA data. At the leaf level, ratios of fluorescence emissions in the blue, green, red and far-red wavelengths sensed responses that were associated with the plant pigments, and were indicative of energy transfer in the photosynthetic process. N stressed corn stands could be distinguish from those with optimally applied N with fluorescence emission spectra obtained from individual corn leaves. Both reflectance and fluorescence methods are sensitive in detecting corn N needs and may be especially powerful in monitoring crop conditions if both types of information can be combined.

  19. Spatial pattern of nitrogen deposition flux over Czech forests: a novel approach accounting for unmeasured nitrogen species

    Science.gov (United States)

    Hůnová, Iva; Stoklasová, Petra; Kurfürst, Pavel; Vlček, Ondřej; Schovánková, Jana; Stráník, Vojtěch

    2015-04-01

    Nitrogen plays an important role in the biogeochemistry of forests as an essential plant nutrient and indispensable substance for many reactions in living cell. Most temperate forests are N-limited (Townsend, 1999), and increased nitrogen deposition results in many negative environmental effects, such as eutrofication, acidification, and loss of biodiversity (Bobbink et al., 2010). The nitrogen biogeochemical cycle is still poorly understood (Fowler et al., 2014). In studies addressing the association between atmospheric deposition and its impacts on ecosystems, a reliable estimation of N deposition is a key factor of successful approach of this issue. The quantification of real deposition of nitrogen is a complicated task, however, due to several reasons: only some constituents are regularly measured, and throughfall is not a relevant proxy for estimation of the total deposition due to complicated interchange of nitrogen between forest canopy, understory, and atmosphere. There are studies estimating the total nitrogen deposition at one particular site, on the other hand, there are studies estimating the total nitrogen deposition over a larger domain, such as e.g. Europe. The studies for a middle scale, like one country, are practically lacking with few exceptions (Fowler et al., 2005). The advantage of such a country-scale approach is that measured constituents might be mapped in detail, which enhances also spatial accuracy and reliability. The ambient air quality monitoring in the Czech Republic is paid an appreciable attention (Hůnová, 2001) due to the fact, that in the recent past its territory belonged to the most polluted parts of Europe. The time trends and spatial patterns of atmospheric deposition were published (Hůnová et al. 2014). It is obvious, however, that nitrogen deposition is substantially underestimated, particularly due not fully accounted for dry and occult deposition. We present an advanced approach for estimation of spatial pattern of

  20. Assessing Nitrogen Treatment Efficiency in Schima Superba Seedlings Detected Using Hyperspectral Reflectance

    Directory of Open Access Journals (Sweden)

    Miaomiao Cheng

    2014-01-01

    Full Text Available The sharp change in nitrate (N deposition fluxes due to anthropogenic influences has major consequences for terrestrial plant productivity. Early detection of plants under nitrate stress is important for forest management in the subtropical region. This study used leaf-scale hyperspectral reflectance measurements to detect the seedling growth response of Schima superba (S. superba under simulated N deposition during a period of two years. Two-year-old S. superba seedlings were planted under natural field conditions and treated with four N treatments at CK, LN-6, MN-10, and HN-24g N m-2 year-1. The chlorophyll content and leaf reflectance were examined to detect the N addition temporal effects. Results indicated that S. superba responded significantly with differences in chlorophyll content and leaf reflectance to N additional treatment. Compared with the N deficiency (CK plots, plots with higher N addition rate (HN reduced the chlorophyll concentration of S. superba seedlings. However, the long-term observed impact of LN and MN treatments increased the S. superba chlorophyll during the two years. Nitrogen additional treatments can be distinguished using the hyperspectral indices (R700/R720, R695/R420, and R695/R760 retrieved from the differences in leaf reflectance at the green spectrum and the red spectrum. The derivative shift to longer wavelength peaks with increasing N supply, accompanied by the increase in chlorophyll content. Leaf reflectance at 559 nm was negatively correlated with leaf chlorophyll content (R = -0.77. The identified N specific spectral ratios may be used for image interpretation and plant N status diagnosis for site-specific N management.

  1. Interspecific Plant Interactions Reflected in Soil Bacterial Community Structure and Nitrogen Cycling in Primary Succession

    Directory of Open Access Journals (Sweden)

    Joseph E. Knelman

    2018-02-01

    Full Text Available Past research demonstrating the importance plant–microbe interactions as drivers of ecosystem succession has focused on how plants condition soil microbial communities, impacting subsequent plant performance and plant community assembly. These studies, however, largely treat microbial communities as a black box. In this study, we sought to examine how emblematic shifts from early successional Alnus viridus ssp. sinuata (Sitka alder to late successional Picea sitchensis (Sitka spruce in primary succession may be reflected in specific belowground changes in bacterial community structure and nitrogen cycling related to the interaction of these two plants. We examined early successional alder-conditioned soils in a glacial forefield to delineate how alders alter the soil microbial community with increasing dominance. Further, we assessed the impact of late-successional spruce plants on these early successional alder-conditioned microbiomes and related nitrogen cycling through a leachate addition microcosm experiment. We show how increasingly abundant alder select for particular bacterial taxa. Additionally, we found that spruce leachate significantly alters the composition of these microbial communities in large part by driving declines in taxa that are enriched by alder, including bacterial symbionts. We found these effects to be spruce specific, beyond a general leachate effect. Our work also demonstrates a unique influence of spruce on ammonium availability. Such insights bolster theory relating the importance of plant–microbe interactions with late-successional plants and interspecific plant interactions more generally.

  2. Interspecific Plant Interactions Reflected in Soil Bacterial Community Structure and Nitrogen Cycling in Primary Succession.

    Science.gov (United States)

    Knelman, Joseph E; Graham, Emily B; Prevéy, Janet S; Robeson, Michael S; Kelly, Patrick; Hood, Eran; Schmidt, Steve K

    2018-01-01

    Past research demonstrating the importance plant-microbe interactions as drivers of ecosystem succession has focused on how plants condition soil microbial communities, impacting subsequent plant performance and plant community assembly. These studies, however, largely treat microbial communities as a black box. In this study, we sought to examine how emblematic shifts from early successional Alnus viridus ssp. sinuata (Sitka alder) to late successional Picea sitchensis (Sitka spruce) in primary succession may be reflected in specific belowground changes in bacterial community structure and nitrogen cycling related to the interaction of these two plants. We examined early successional alder-conditioned soils in a glacial forefield to delineate how alders alter the soil microbial community with increasing dominance. Further, we assessed the impact of late-successional spruce plants on these early successional alder-conditioned microbiomes and related nitrogen cycling through a leachate addition microcosm experiment. We show how increasingly abundant alder select for particular bacterial taxa. Additionally, we found that spruce leachate significantly alters the composition of these microbial communities in large part by driving declines in taxa that are enriched by alder, including bacterial symbionts. We found these effects to be spruce specific, beyond a general leachate effect. Our work also demonstrates a unique influence of spruce on ammonium availability. Such insights bolster theory relating the importance of plant-microbe interactions with late-successional plants and interspecific plant interactions more generally.

  3. Effects of nitrogen nutrition on the growth, yield and reflectance characteristics of corn canopies. [Purdue Agronomy Farm, Indiana

    Science.gov (United States)

    Bauer, M. E. (Principal Investigator); Walburg, G.; Daughtry, C. S. T.

    1981-01-01

    Spectral and agronomic measurements were collected from corn (Zea mays L.) canopies under four nitrogen treatment levels (0, 67, 134, and 202 kg/ha) on 11 dates during 1978 and 12 dates during 1979. Data were analyzed to determine the relationship between the spectral responses of canopies and their argonomic characteristics as well as the spectral separability of the four treatments. Red reflectance was increased, while the near infrared reflectance was decreased for canopies under nitrogen deprivation. Spectral differences between treatments were seen throughout each growing season. The near infrared/red reflectance ratio increased spectral treatment differences over those shown by single band reflectance measures. Of the spectral variables examined, the near infrared/red reflectance ratio most effectively separated the treatments. Differences in spectral response between treatments were attributed to varying soil cover, leaf area index, and leaf pigmentation values, all of which changed with N treatment.

  4. Patterns of nutrient utilization. Implications for nitrogen metabolism

    International Nuclear Information System (INIS)

    Oldham, J.D.

    1983-01-01

    Nutrients react within both the rumen and the ruminant body, and the patterns of availability of different nutrients greatly influence their net utilization. In the rumen, microbial capture of N substrates, especially ammonia, depends on the degree of synchronization between rates of production of N substrates and of ATP to drive microbial protein synthesis. The form of dietary carbohydrate and of dietary N and the frequency of feeding can all affect the efficiency of microbial growth and digestion. The pattern of supply of nutrients to the body will also influence nutrient utilization. Disparities between diurnal patterns of supply of volatile fatty acids from the rumen and amino acids from the intestines will result in changes in balance of metabolic pathways. The balance between supply of glucogenic and lipogenic nutrients will influence efficiency of fattening. A major factor determining the pattern of utilization/metabolism of amino acids is the metabolic demand for protein synthesis, which varies with physiological state. (author)

  5. Precise shape reconstruction by active pattern in total-internal-reflection-based tactile sensor.

    Science.gov (United States)

    Saga, Satoshi; Taira, Ryosuke; Deguchi, Koichiro

    2014-03-01

    We are developing a total-internal-reflection-based tactile sensor in which the shape is reconstructed using an optical reflection. This sensor consists of silicone rubber, an image pattern, and a camera. It reconstructs the shape of the sensor surface from an image of a pattern reflected at the inner sensor surface by total internal reflection. In this study, we propose precise real-time reconstruction by employing an optimization method. Furthermore, we propose to use active patterns. Deformation of the reflection image causes reconstruction errors. By controlling the image pattern, the sensor reconstructs the surface deformation more precisely. We implement the proposed optimization and active-pattern-based reconstruction methods in a reflection-based tactile sensor, and perform reconstruction experiments using the system. A precise deformation experiment confirms the linearity and precision of the reconstruction.

  6. Attachment patterns and Reflective Functioning in Traumatized Refugees

    DEFF Research Database (Denmark)

    Riber, Karin

    , attachment systems, emotion-regulation, and personality. Attachment research on the consequences of organized violence and forced migration is sparse and research in PTSD-treatment for refugees is lacking behind. Cumulative pre-migration traumatic experiences and ongoing post-migration stressors might lead...... Psychiatry, Denmark. June 2011-March 2012 patients fulfilling inclusion criteria entered the trial. The present sample consisted of those of the 135 patients who were Arabic-speaking (N=67). Measures involved the Adult Attachment Interview, The Reflective Functioning Scale, Revised Adult Attachment Scale...... and reflective functioning will be described and implications for psychotherapy discussed. Keywords: Adult attachment, reflective functioning, refugee traumatisation....

  7. Patterns in Stable Isotope Values of Nitrogen and Carbon in ...

    Science.gov (United States)

    Stable isotope measurements of nitrogen and carbon (15N, 13ddC) are often used to characterize estuarine, nearshore, and open ocean ecosystems. Reliable information about the spatial distribution of base-level stable isotope values, often represented by primary producers, is critical to interpreting values in these ecosystems. While base-level isotope data are generally readily available for estuaries, nearshore coastal waters, and the open ocean, the continental shelf is less studied. To address this, and as a first step toward developing a surrogate for base-level isotopic signature in this region, we collected surface and deep water samples from the United States’ eastern continental shelf in the Western Atlantic Ocean, from the Gulf of Maine to Cape Hatteras, periodically between 2000 and 2013. During the study, particulate matter 15dN values ranged from 0.8 to 17.4‰, and 13dC values from −26.4 to −15.6‰over the region. We used spatial autocorrelation analysis and random forest modeling to examine the spatial trends and potential environmental drivers of the stable isotope values. We observed general trends toward lower values for both nitrogen and carbon isotopes at the seaward edge of the shelf. Conversely, higher 15dN and 13dC values were observed on the landward edge of the shelf, in particular in the southern portion of the sampling area. Across all sites, the magnitude of the difference between the 15dN of subsurface and surface particulate m

  8. Foliar Reflectance and Fluorescence Responses for Plants Under Nitrogen Stress Determined with Active and Passive Systems

    Science.gov (United States)

    Middleton, E. M.; McMurtrey, J. E.; Campbell, P. K. Entcheva; Corp, L. A.; Butcher, L. M.; Chappelle, E. W.

    2003-01-01

    Vegetation productivity is driven by nitrogen (N) availability in soils. Both excessive and low soil N induce physiological changes in plant foliage. In 2001, we examined the use of spectral fluorescence and reflectance measurements to discriminate among plants provided different N fertilizer application rates: 20%, 50%, 100% and 150% of optimal N levels. A suite of optical, fluorescence, and biophysical measurements were collected on leaves from field grown corn (Zea mays L.) and soybean plants (Glycine max L.) grown in pots (greenhouse + ambient sunlight daily). Three types of steady state laser-induced fluorescence measurements were made on adaxial and abaxial surfaces: 1) fluorescence images in four 10 nm bands (blue, green, red, far-red) resulting from broad irradiance excitation; 2) emission spectra (5 nm resolution) produced by excitation at single wavelengths (280,380 or 360, and 532 nm); and 3) excitation spectra (2 nm resolution), with emission wavelengths fixed at wavelengths centered on selected solar Fraunhofer lines (532,607,677 and 745 nm). Two complementary sets of high resolution (less than 2 nm) optical spectra were acquired for both adaxial and abaxial leaf surfaces: 1) optical properties (350-2500 nm) for reflectance, transmittance, and absorptance; and 2) reflectance spectra (500-1000 nm) acquired with and without a short pass filter at 665 nm to determine the fluorescence contribution to apparent reflectance in the 650-750 spectrum, especially at the 685 and 740 nm chlorophyll fluorescence (ChIF) peaks. The strongest relationships between foliar chemistry and optical properties were demonstrated for C/N content and two optical parameters associated with the red edge inflection point. Select optical properties and ChIF parameters were highly correlated for both species. A significant contribution of ChIF to apparent reflectance was observed, averaging 10-25% at 685 nm and 2 - 6% at 740 nm over all N treatments. Discrimination of N treatment

  9. Nitrogen

    Science.gov (United States)

    Apodaca, Lori E.

    2013-01-01

    The article presents an overview of the nitrogen chemical market as of July 2013, including the production of ammonia compounds. Industrial uses for ammonia include fertilizers, explosives, and plastics. Other topics include industrial capacity of U.S. ammonia producers CF Industries Holdings Inc., Koch Nitrogen Co., PCS Nitrogen, Inc., and Agrium Inc., the impact of natural gas prices on the nitrogen industry, and demand for corn crops for ethanol production.

  10. Spatiotemporal patterns of non-point source nitrogen loss in an agricultural catchment

    Directory of Open Access Journals (Sweden)

    Jian-feng Xu

    2016-04-01

    Full Text Available Non-point source nitrogen loss poses a risk to sustainable aquatic ecosystems. However, non-point sources, as well as impaired river segments with high nitrogen concentrations, are difficult to monitor and regulate because of their diffusive nature, budget constraints, and resource deficiencies. For the purpose of catchment management, the Bayesian maximum entropy approach and spatial regression models have been used to explore the spatiotemporal patterns of non-point source nitrogen loss. In this study, a total of 18 sampling sites were selected along the river network in the Hujiashan Catchment. Over the time period of 2008–2012, water samples were collected 116 times at each site and analyzed for non-point source nitrogen loss. The morphometric variables and soil drainage of different land cover types were studied and considered potential factors affecting nitrogen loss. The results revealed that, compared with the approach using the Euclidean distance, the Bayesian maximum entropy approach using the river distance led to an appreciable 10.1% reduction in the estimation error, and more than 53.3% and 44.7% of the river network in the dry and wet seasons, respectively, had a probability of non-point source nitrogen impairment. The proportion of the impaired river segments exhibited an overall decreasing trend in the study catchment from 2008 to 2012, and the reduction in the wet seasons was greater than that in the dry seasons. High nitrogen concentrations were primarily found in the downstream reaches and river segments close to the residential lands. Croplands and residential lands were the dominant factors affecting non-point source nitrogen loss, and explained up to 70.7% of total nitrogen in the dry seasons and 54.7% in the wet seasons. A thorough understanding of the location of impaired river segments and the dominant factors affecting total nitrogen concentration would have considerable importance for catchment management.

  11. Sociocultural patterning of neural activity during self-reflection

    DEFF Research Database (Denmark)

    Ma, Yina; Bang, Dan; Wang, Chenbo

    2014-01-01

    ) in Chinese than in Danish participants. Moreover, the group difference in TPJ activity was mediated by a measure of a cultural value (i.e., interdependence of self-construal). Our findings suggest that individuals in different sociocultural contexts may learn and/or adopt distinct strategies for self-reflection...

  12. Natural 15N abundance of soil N pools and N2O reflect the nitrogen dynamics of forest soils

    DEFF Research Database (Denmark)

    Pörtl, K.; Zechmeister-Boltenstern, S.; Wanek, W.

    2007-01-01

    Natural N-15 abundance measurements of ecosystem nitrogen (N) pools and N-15 pool dilution assays of gross N transformation rates were applied to investigate the potential of delta N-15 signatures of soil N pools to reflect the dynamics in the forest soil N cycle. Intact soil cores were collected...

  13. Will algorithms modified with soil and weather information improve in-field reflectance-sensing corn nitrogen applications?

    Science.gov (United States)

    Nitrogen (N) needs to support corn (Zea mays L.) production can be highly variable within fields. Canopy reflectance sensing for assessing crop N health has been implemented on many farmers’ fields to side-dress or top-dress variable-rate N application, but at times farmers report the performance of...

  14. Trends in nitrogen isotope ratios of juvenile winter flounder reflect changing nitrogen inputs to Rhode Island, USA estuarine systems.

    Science.gov (United States)

    Pruell, Richard J; Taplin, Bryan K; Miller, Kenneth M

    2017-05-15

    Nitrogen isotope ratios (δ 15 N) in juvenile winter flounder, Pseudopleuronectes americanus, were used to examine changes in nitrogen inputs to several Rhode Island, USA estuarine systems. Fish were collected over two three-year periods with a ten-year interval between sampling periods (2002-2004 and 2012-2014). During that interval numerous changes to nutrient management practices were initiated in the watersheds of these estuarine systems including the upgrade of several major wastewater treatment facilities that discharge to Narragansett Bay, which significantly reduced nitrogen inputs. Following these reductions, the δ 15 N values of flounder in several of the systems decreased as expected; however, isotope ratios in fish from upper Narragansett Bay significantly increased. We believe that low δ 15 N values measured in 2002-2004 were related to concentration-dependent fractionation at this location. Increased δ 15 N values measured between 2012 and 2014 may indicate reduced fractionation or that changes in wastewater treatment processes altered the nitrogen isotopic ratios of the effluents. Published by Elsevier Ltd.

  15. Isotopic patterns in caps and stipes in sporocarps reveal patterns of organic nitrogen use by ectomycorrhizal fungi

    Science.gov (United States)

    Hobbie, Erik; Ouimette, Andrew; Chen, Janet

    2016-04-01

    Current ecosystem models use inorganic nitrogen as the currency of nitrogen acquisition by plants. However, many trees may gain access to otherwise unavailable soil resources, such as soil organic nitrogen, through their symbioses with ectomycorrhizal fungi, and this pathway of nitrogen acquisition may therefore be important in understanding plant responses to environmental change. Different functional groups of ectomycorrhizal fungi vary in their ability to enzymatically access protein and other soil resources. Such fungal parameters as hyphal hydrophobicity, the presence of rhizomorphs (long-distance transport structures), and exploration strategies (e.g., short-distance versus long-distance, mat formation) correspond with how fungi interact with and explore the environment, and the proportions of different exploration types present will shift along environmental gradients such as nitrogen availability. Isotopic differences between caps and stipes may provide a means to test for organic nitrogen use, since caps and stipes differ in δ13C and δ15N as a result of variable proportions of protein and other classes of compounds, and protein should differ isotopically among de novo synthesis, litter sources, and soil sources. Here, we propose that (1) isotopic differences between caps and stipes could be related to organic nitrogen uptake and to the δ13C and δ15N values of different pools of soil-derived or de novo-synthesized amino acids; (2) these isotopic differences will reflect greater acquisition of soil-derived organic nitrogen by exploration types of greater enzymatic capabilities to degrade recalcitrant nitrogen forms, specifically long-distance, medium-distance fringe, and medium-distance mat exploration types. To test these hypotheses, we use a dataset of isotopic values, %N, and %C in 208 cap/stipe samples collected from Oregon, western USA. δ13C differences in caps and stipes in a multiple regression model had an adjusted r2 of 0.292 (p Ncap-stipe (20

  16. Foliar Reflectance and Fluorescence Responses for Corn and Soybean Plants Under Nitrogen Stress

    Science.gov (United States)

    Middleton, E. M.; Campbell, P. K. Entcheva; Corp, L. A.; Butcher, L. M.; McMurtrey, J. E.

    2003-01-01

    We are investigating the use of spectral indices derived from actively induced fluorescence spectra and passive optical spectra. We examined the influence of photosynthetic pigment, carbon (C) and nitrogen (N) content on the spectral fluorescence and passive optical property characteristics of mature, upper leaves from plants provided different N fertilizer application rates: 20%, 50%, 100% and 150% of recommended N levels. A suite of optical, fluorescence, and biophysical measurements were collected on leaves from field grown corn (Zea mays L.) and soybean plants (Glycine max L.) grown in pots (greenhouse + ambient sunlight. Steady state laser-induced fluorescence emission spectra (5 nm resolution) were obtained from adaxial and abaxial surfaces resulting from excitation at single wavelengths (280, 380 or 360, and 532 nm). For emission spectra produced by each of these excitation wavelengths, ratios of emission peaks were calculated, including the red far-red chlorophyll fluorescence (ChlF) ratio (F685/F740) and the far-red/green (F740/F525) ratio. High resolution (treatment groups was possible with specific fluorescence band ratios (e.g., F740/F525 obtained with 380 nm excitation). Higher ChlF and blue-green emissions were measured from the abaxial leaf surfaces. Abaxial surfaces also produced higher reflectances, in general, in the 400-800 nm spectrum.

  17. Stream Nitrogen Inputs Reflect Groundwater Across a Snowmelt-Dominated Montane to Urban Watershed.

    Science.gov (United States)

    Hall, Steven J; Weintraub, Samantha R; Eiriksson, David; Brooks, Paul D; Baker, Michelle A; Bowen, Gabriel J; Bowling, David R

    2016-02-02

    Snowmelt dominates the hydrograph of many temperate montane streams, yet little work has characterized how streamwater sources and nitrogen (N) dynamics vary across wildland to urban land use gradients in these watersheds. Across a third-order catchment in Salt Lake City, Utah, we asked where and when groundwater vs shallow surface water inputs controlled stream discharge and N dynamics. Stream water isotopes (δ(2)H and δ(18)O) reflected a consistent snowmelt water source during baseflow. Near-chemostatic relationships between conservative ions and discharge implied that groundwater dominated discharge year-round across the montane and urban sites, challenging the conceptual emphasis on direct stormwater inputs to urban streams. Stream and groundwater NO3(-) concentrations remained consistently low during snowmelt and baseflow in most montane and urban stream reaches, indicating effective subsurface N retention or denitrification and minimal impact of fertilizer or deposition N sources. Rather, NO3(-) concentrations increased 50-fold following urban groundwater inputs, showing that subsurface flow paths potentially impact nutrient loading more than surficial land use. Isotopic composition of H2O and NO3(-) suggested that snowmelt-derived urban groundwater intercepted NO3(-) from leaking sewers. Sewer maintenance could potentially mitigate hotspots of stream N inputs at mountain/valley transitions, which have been largely overlooked in semiarid urban ecosystems.

  18. Chaos, patterns, coherent structures, and turbulence: Reflections on nonlinear science.

    Science.gov (United States)

    Ecke, Robert E

    2015-09-01

    The paradigms of nonlinear science were succinctly articulated over 25 years ago as deterministic chaos, pattern formation, coherent structures, and adaptation/evolution/learning. For chaos, the main unifying concept was universal routes to chaos in general nonlinear dynamical systems, built upon a framework of bifurcation theory. Pattern formation focused on spatially extended nonlinear systems, taking advantage of symmetry properties to develop highly quantitative amplitude equations of the Ginzburg-Landau type to describe early nonlinear phenomena in the vicinity of critical points. Solitons, mathematically precise localized nonlinear wave states, were generalized to a larger and less precise class of coherent structures such as, for example, concentrated regions of vorticity from laboratory wake flows to the Jovian Great Red Spot. The combination of these three ideas was hoped to provide the tools and concepts for the understanding and characterization of the strongly nonlinear problem of fluid turbulence. Although this early promise has been largely unfulfilled, steady progress has been made using the approaches of nonlinear science. I provide a series of examples of bifurcations and chaos, of one-dimensional and two-dimensional pattern formation, and of turbulence to illustrate both the progress and limitations of the nonlinear science approach. As experimental and computational methods continue to improve, the promise of nonlinear science to elucidate fluid turbulence continues to advance in a steady manner, indicative of the grand challenge nature of strongly nonlinear multi-scale dynamical systems.

  19. Foliar Reflectance and Fluorescence Responses for Corn and Soybean Plants Under Nitrogen Stress

    Science.gov (United States)

    Middleton, E. M.; Campbell, P. K. Entcheva; Corp, L. A.; Butcher, L. M.; McMurtrey, J. E.

    2003-01-01

    We are investigating the use of spectral indices derived from actively induced fluorescence spectra and passive optical spectra. We examined the influence of photosynthetic pigment, carbon (C) and nitrogen (N) content on the spectral fluorescence and passive optical property characteristics of mature, upper leaves from plants provided different N fertilizer application rates: 20%, 50%, 100% and 150% of recommended N levels. A suite of optical, fluorescence, and biophysical measurements were collected on leaves from field grown corn (Zea mays L.) and soybean plants (Glycine max L.) grown in pots (greenhouse + ambient sunlight. Steady state laser-induced fluorescence emission spectra (5 nm resolution) were obtained from adaxial and abaxial surfaces resulting from excitation at single wavelengths (280, 380 or 360, and 532 nm). For emission spectra produced by each of these excitation wavelengths, ratios of emission peaks were calculated, including the red far-red chlorophyll fluorescence (ChlF) ratio (F685/F740) and the far-red/green (F740/F525) ratio. High resolution (< 3 nm) optical spectra (350-2500 nm) of reflectance, transmittance, and absorptance were also acquired for both adaxial and abaxial leaf surfaces. Species differences were demonstrated for several optical parameters. A 'red edge' derivative ratio determined from transmittance spectra [as the maximum first deivative, between 650-750 nm, normalized to the value at 744 nm, or Dmax/D744], was strongly associated with the C/N ratio (r(exp 2) = 0.90, P +/- 0.001). This ratio, calculated from reflectance spectra, was inversely related to chlorophyll b content (r(exp 2) = 0.91, P +/- 0.001) as was the ChlF (F685/F740) ratio obtained with 532 nm excitation (r(exp 2) = 0.76, P +/- 0.01). Discrimination of N treatment groups was possible with specific fluorescence band ratios (e.g., F740/F525 obtained with 380 nm excitation). Higher ChlF and blue-green emissions were measured from the abaxial leaf surfaces

  20. Sociocultural patterning of neural activity during self-reflection.

    Science.gov (United States)

    Ma, Yina; Bang, Dan; Wang, Chenbo; Allen, Micah; Frith, Chris; Roepstorff, Andreas; Han, Shihui

    2014-01-01

    Western cultures encourage self-construals independent of social contexts, whereas East Asian cultures foster interdependent self-construals that rely on how others perceive the self. How are culturally specific self-construals mediated by the human brain? Using functional magnetic resonance imaging, we monitored neural responses from adults in East Asian (Chinese) and Western (Danish) cultural contexts during judgments of social, mental and physical attributes of themselves and public figures to assess cultural influences on self-referential processing of personal attributes in different dimensions. We found that judgments of self vs a public figure elicited greater activation in the medial prefrontal cortex (mPFC) in Danish than in Chinese participants regardless of attribute dimensions for judgments. However, self-judgments of social attributes induced greater activity in the temporoparietal junction (TPJ) in Chinese than in Danish participants. Moreover, the group difference in TPJ activity was mediated by a measure of a cultural value (i.e. interdependence of self-construal). Our findings suggest that individuals in different sociocultural contexts may learn and/or adopt distinct strategies for self-reflection by changing the weight of the mPFC and TPJ in the social brain network.

  1. Do networks of social interactions reflect patterns of kinship?

    Directory of Open Access Journals (Sweden)

    Joah R. MADDEN, Johanna F. NIELSEN, Tim H. CLUTTON-BROCK

    2012-04-01

    Full Text Available The underlying kin structure of groups of animals may be glimpsed from patterns of spatial position or temporal association between individuals, and is presumed to facilitate inclusive fitness benefits. Such structure may be evident at a finer, behavioural, scale with individuals preferentially interacting with kin. We tested whether kin structure within groups of meerkats Suricata suricatta matched three forms of social interaction networks: grooming, dominance or foraging competitions. Networks of dominance interactions were positively related to networks of kinship, with close relatives engaging in dominance interactions with each other. This relationship persisted even after excluding the breeding dominant pair and when we restricted the kinship network to only include links between first order kin, which are most likely to be able to discern kin through simple rules of thumb. Conversely, we found no relationship between kinship networks and either grooming networks or networks of foraging competitions. This is surprising because a positive association between kin in a grooming network, or a negative association between kin in a network of foraging competitions offers opportunities for inclusive fitness benefits. Indeed, the positive association between kin in a network of dominance interactions that we did detect does not offer clear inclusive fitness benefits to group members. We conclude that kin structure in behavioural interactions in meerkats may be driven by factors other than indirect fitness benefits, and that networks of cooperative behaviours such as grooming may be driven by direct benefits accruing to individuals perhaps through mutualism or manipulation [Current Zoology 58 (2: 319-328, 2012].

  2. Do networks of social interactions reflect patterns of kinship?

    Institute of Scientific and Technical Information of China (English)

    Joah R. MADDEN; Johanna F. NIEL SEN; Tim H. CLUTTON-BROCK

    2012-01-01

    The underlying kin structure of groups of animals may be glimpsed from patterns of spatial position or temporal association between individuals,and is presumed to facilitate inclusive fitness benefits.Such structure may be evident at a finer,behavioural,scale with individuals preferentially interacting with kin.We tested whether kin structure within groups of meerkats Suricata suricatta matched three forms of social interaction networks:grooming,dominance or foraging competitions.Networks of dominance interactions were positively related to networks of kinship,with close relatives engaging in dominance interactions with each other.This relationship persisted even after excluding the breeding dominant pair and when we restricted the kinship network to only include links between first order kin,which are most likely to be able to discern kin through simple rules of thumb.Conversely,we found no relationship between kinship networks and either grooming networks or networks of foraging competitions.This is surprising because a positive association between kin in a grooming network,or a negative association between kin in a network of foraging competitions offers opportunities for inclusive fitness benefits.Indeed,the positive association between kin in a network of dominance interactions that we did detect does not offer clear inclusive fitness benefits to group members.We conclude that kin structure in behavioural interactions in meerkats may be driven by factors other than indirect fitness benefits,and that networks of cooperative behaviours such as grooming may be driven by direct benefits accruing to individuals perhaps through mutualism or manipulation [Current Zoology 58 (2):319-328,2012].

  3. Evaluation of nitrogen uptake patterns in spring and winter wheat in western Oregon

    International Nuclear Information System (INIS)

    Baloch, D.M.; Malghani, M.A.K.; Khan, M.A.; Kakar, E.

    2010-01-01

    An understanding of the ground nitrogen (N) uptake pattern for wheat (Triticum aestivum L.) is essential to facilitate nitrogen management. The purpose of this study was to determine the nitrogen uptake pattern of spring and winter wheat grown in western Oregon, USA. Data used in this study were obtained from three different trials. For spring wheat rotation trials five spring wheat cultivars were used. Fertilizer N (16-16-16-4) at the rate of 140 kg ha/sup -1/ was applied at the time of planting. In small plot rotation trials five fertilizer treatments - 0, 50, 100,150 and 200 kg N ha/sup -1/ were used. Rotations include winter wheat following clover and winter wheat following oat. The N uptake and dry matter yield of winter wheat were also determined from unfertilized plots of wheat trial. The maximum N uptake for spring wheat and winter wheat were at 1100 and 2000 accumulated growing degree days (GDD), before Feekes 10, respectively. The maximum N uptake rate for spring wheat, 0.038 kg N GDD/sup -1/, occurred at 750 GDD and the peak N uptake was observed approximately 35 days after Feekes 2. Nitrogen uptake in winter wheat was significantly affected by rotations. (author)

  4. Spatial reflection patterns of iridescent wings of male pierid butterflies: curved scales reflect at a wider angle than flat scales.

    Science.gov (United States)

    Pirih, Primož; Wilts, Bodo D; Stavenga, Doekele G

    2011-10-01

    The males of many pierid butterflies have iridescent wings, which presumably function in intraspecific communication. The iridescence is due to nanostructured ridges of the cover scales. We have studied the iridescence in the males of a few members of Coliadinae, Gonepteryx aspasia, G. cleopatra, G. rhamni, and Colias croceus, and in two members of the Colotis group, Hebomoia glaucippe and Colotis regina. Imaging scatterometry demonstrated that the pigmentary colouration is diffuse whereas the structural colouration creates a directional, line-shaped far-field radiation pattern. Angle-dependent reflectance measurements demonstrated that the directional iridescence distinctly varies among closely related species. The species-dependent scale curvature determines the spatial properties of the wing iridescence. Narrow beam illumination of flat scales results in a narrow far-field iridescence pattern, but curved scales produce broadened patterns. The restricted spatial visibility of iridescence presumably plays a role in intraspecific signalling.

  5. Patterns of cross-sensitivity in the responses of clonal subpopulations isolated from the RIF-1 mouse sarcoma to selected nitrosoureas and nitrogen mustards.

    Science.gov (United States)

    Reeve, J. G.; Wright, K. A.; Workman, P.

    1984-01-01

    The response of clonal subpopulations isolated from the RIF-1 mouse sarcoma to melphalan treatment is independent of cell ploidy, whereas a clear relationship exists between ploidy and cell sensitivity to CCNU treatment. In the present study RIF-1 clones have been exposed to nitrogen mustard, aniline mustard and chlorambucil, and to nitrosoureas BCNU, MeCCNU and chlorozotocin, in order to evaluate whether or not the different physiochemical and biological activities of these agents would affect the patterns of drug sensitivity obtained for melphalan and CCNU. Irrespective of the different lipophilicities, transport properties and chemical reactivities of the nitrogen mustards, RIF-1 clones showed the same pattern of sensitivity as previously observed for melphalan. Similarly, RIF-1 clones when exposed to nitrosoureas BCNU, MeCCNU and chlorozotocin, showed the same pattern of sensitivity as that obtained for CCNU exposure. These data suggest (a) that the variation in the sensitivity of RIF-1 clones to treatment by the nitrogen mustards is unlikely to reflect differences in either membrane permeability or in drug transport and (b) that the ploidy dependent nitrosourea responses shown by RIF-1 clones similarly do not reflect differences in drug uptake. PMID:6466534

  6. Phase retrieval from reflective fringe patterns of double-sided transparent objects

    International Nuclear Information System (INIS)

    Huang, Lei; Asundi, Anand Krishna

    2012-01-01

    ‘Ghosted’ fringe patterns simultaneously reflected from both the upper and lower sides of a transparent target in the fringe reflection technique are captured for transparent surface 3D shape measurement, but the phase retrieval from the captured ‘ghosted’ fringe patterns is still not solved. A novel method is proposed to solve this issue by using two sets of phase-shifted fringe patterns with slightly different frequencies. The nonlinear least-squares method is used to estimate the fringe phase and modulation from both front and rear interfaces. Several simulations are done to show the feasibility of the proposed method. The influence of fringe noise on the algorithm is studied as well, which indicates that the proposed method is able to retrieve the phase from double-sided reflective fringe patterns with fringe noise equivalent to that in practical measurements. The merits and limitations of the method are discussed and recommendations for future studies are made. (paper)

  7. Increasing plant use of organic nitrogen with elevation is reflected in nitrogen uptake rates and ecosystem delta15N.

    Science.gov (United States)

    Averill, Colin; Finzi, Adrien

    2011-04-01

    It is hypothesized that decreasing mean annual temperature and rates of nitrogen (N) cycling causes plants to switch from inorganic to organic forms of N as the primary mode of N nutrition. To test this hypothesis, we conducted field experiments and collected natural-abundance delta15N signatures of foliage, soils, and ectomycorrhizal sporocarps along a steep elevation-climate gradient in the White Mountains, New Hampshire, USA. Here we show that with increasing elevation organic forms of N became the dominant source of N taken up by hardwood and coniferous tree species based on dual-labeled glycine uptake analysis, an important confirmation of an emerging theory for the biogeochemistry of the N cycle. Variation in natural abundance foliar delta15N with elevation was also consistent with increasing organic N uptake, though a simple, mass balance model demonstrated that the uptake of delta15N depleted inorganic N, rather than fractionation upon transfer of N from mycorrhizal fungi, best explains variations in foliar delta15N with elevation.

  8. Distinguishing nitrogen fertilization levels in field corn (Zea mays L.) with actively induced fluorescence and passive reflectance measurements

    International Nuclear Information System (INIS)

    McMurtrey, J.E. III; Chappelle, E.W.; Kim, M.S.; Meisinger, J.J.; Corp, L.A

    1994-01-01

    Laser-induced fluorescence (LIF) is an active sensing technique capable of capturing immediate and specific indications of changes in plant physiology and metabolism as they relate to the concentration and photosynthetic activity of the plant pigments. Reflectance is a passive sensing technique that can capture differences in the concentration of the primary plant pigments. Fluorescence and reflectance were compared for their ability to measure levels of plant stress that are of agronomic importance in corn (Zea mays L.) crops. Laboratory LIF and reflectance spectra were made on excised leaves from field grown corn. Changes in the visible region of the spectrum were compared between groups of plants fertilized with seven different levels of nitrogen (N) fertilization. A pulsed nitrogen laser emitting photons at a wavelength of 337 nm was used as a fluorescence excitation source. Differences in maximum intensity of fluorescence occurred at 440 nm, 525 nm, 685 nm, and 740 nm. Significant separations were found between levels of N fertilization at several LIF wavelength ratios. Several reflectance algorithms also produced significant separations between certain levels of N fertilization

  9. Comparison of Measurements and FluorMOD Simulations for Solar Induced Chlorophyll Fluorescence and Reflectance of a Corn Crop under Nitrogen Treatments [SIF and Reflectance for Corn

    Science.gov (United States)

    Middleton, Elizabeth M.; Corp, Lawrence A.; Campbell, Petya K. E.

    2007-01-01

    The FLuorescence Explorer (FLEX) satellite concept is one of six semifinalist mission proposals selected in 2006 for pre-Phase studies by the European Space Agency (ESA). The FLEX concept proposes to measure passive solar induced chlorophyll fluorescence (SIF) of terrestrial ecosystems. A new spectral vegetation Fluorescence Model (FluorMOD) was developed to include the effects of steady state SIF on canopy reflectance. We used our laboratory and field measurements previously acquired from foliage and canopies of corn (Zea mays L.) under controlled nitrogen (N) fertilization to parameterize and evaluate FluorMOD. Our data included biophysical properties, fluorescence (F) and reflectance spectra for leaves; reflectance spectra of canopies and soil; solar irradiance; plot-level leaf area index; and canopy SIF emissions determined using the Fraunhofer Line Depth principal for the atmospheric telluric oxygen absorption features at 688 nm (O2-beta) and 760 nm (O2-alpha). FluorMOD simulations implemented in the default "look-up-table" mode did not reproduce the observed magnitudes of leaf F, canopy SIF, or canopy reflectance. However, simulations for all of these parameters agreed with observations when the default FluorMOD information was replaced with measurements, although N treatment responses were underestimated. Recommendations were provided to enhance FluorMOD's potential utility in support of SIF field experiments and studies of agriculture and ecosystems.

  10. Reflection Patterns Generated by Condensed-Phase Oblique Detonation Interaction with a Rigid Wall

    Science.gov (United States)

    Short, Mark; Chiquete, Carlos; Bdzil, John; Meyer, Chad

    2017-11-01

    We examine numerically the wave reflection patterns generated by a detonation in a condensed phase explosive inclined obliquely but traveling parallel to a rigid wall as a function of incident angle. The problem is motivated by the characterization of detonation-material confiner interactions. We compare the reflection patterns for two detonation models, one where the reaction zone is spatially distributed, and the other where the reaction is instantaneous (a Chapman-Jouguet detonation). For the Chapman-Jouguet model, we compare the results of the computations with an asymptotic study recently conducted by Bdzil and Short for small detonation incident angles. We show that the ability of a spatially distributed reaction energy release to turn flow streamlines has a significant impact on the nature of the observed reflection patterns. The computational approach uses a shock-fit methodology.

  11. Nitrogen

    Science.gov (United States)

    Apodaca, L.E.

    2010-01-01

    Ammonia was produced by 13 companies at 23 plants in 16 states during 2009. Sixty percent of all U.S. ammonia production capacity was centered in Louisiana. Oklahoma and Texas because of those states' large reserves of natural gas, the dominant domestic feedstock. In 2009, U.S. producers operated at about 83 percent of their rated capacity (excluding plants that were idle for the entire year). Five companies — Koch Nitrogen Co.; Terra Industries Inc.; CF Industries Inc.; PCS Nitrogen Inc. and Agrium Inc., in descending order — accounted for 80 percent of the total U.S. ammonia production capacity. U.S. production was estimated to be 7.7 Mt (8.5 million st) of nitrogen (N) content in 2009 compared with 7.85 Mt (8.65 million st) of N content in 2008. Apparent consumption was estimated to have decreased to 12.1 Mt (13.3 million st) of N, a 10-percent decrease from 2008. The United States was the world's fourth-ranked ammonia producer and consumer following China, India and Russia. Urea, ammonium nitrate, ammonium phosphates, nitric acid and ammonium sulfate were the major derivatives of ammonia in the United States, in descending order of importance.

  12. Ectomycorrhizal impacts on plant nitrogen nutrition: emerging isotopic patterns, latitudinal variation and hidden mechanisms.

    Science.gov (United States)

    Mayor, Jordan; Bahram, Mohammad; Henkel, Terry; Buegger, Franz; Pritsch, Karin; Tedersoo, Leho

    2015-01-01

    Ectomycorrhizal (EcM)-mediated nitrogen (N) acquisition is one main strategy used by terrestrial plants to facilitate growth. Measurements of natural abundance nitrogen isotope ratios (denoted as δ(15)N relative to a standard) increasingly serve as integrative proxies for mycorrhiza-mediated N acquisition due to biological fractionation processes that alter (15)N:(14)N ratios. Current understanding of these processes is based on studies from high-latitude ecosystems where plant productivity is largely limited by N availability. Much less is known about the cause and utility of ecosystem δ(15)N patterns in the tropics. Using structural equation models, model selection and isotope mass balance we assessed relationships among co-occurring soil, mycorrhizal plants and fungal N pools measured from 40 high- and 9 low-latitude ecosystems. At low latitudes (15)N-enrichment caused ecosystem components to significantly deviate from those in higher latitudes. Collectively, δ(15)N patterns suggested reduced N-dependency and unique sources of EcM (15)N-enrichment under conditions of high N availability typical of the tropics. Understanding the role of mycorrhizae in global N cycles will require reevaluation of high-latitude perspectives on fractionation sources that structure ecosystem δ(15)N patterns, as well as better integration of EcM function with biogeochemical theories pertaining to climate-nutrient cycling relationships. © 2014 John Wiley & Sons Ltd/CNRS.

  13. Nitrogen deficiency detection using reflected shortwave radiation from irrigated corn canopies

    International Nuclear Information System (INIS)

    Blackmer, T.M.; Schepers, J.S.; Varvel, G.E.; Walter-Shea, E.A.

    1996-01-01

    Techniques that measure the N status of corn (Zea mays L.) can aid in management decisions that have economic and environmental implications. This study was conducted to identify reflected electromagnetic wavelengths most sensitive to detecting N deficiencies in a corn canopy with the possibility for use as a management tool. Reflected shortwave radiation was measured from an irrigated corn N response trial with four hybrids and five N rates at 0, 40, 80, 120, and 160 kg N ha -1 in 1992 and 0, 50, 100, 150, and 200 kg N ha -1 in 1993. A portable spectroradiometer was used to measure reflected radiation (400-1100 nm in 1992, 350-1050 nm in 1993) from corn canopies at approximately the R5 growth stage. Regression analyses revealed that reflected radiation near 550 and 710 nm was superior to reflected radiation near 450 or 650 nm for detecting N deficiencies. The ratio of light reflectance between 550 and 600 nm to light reflectance between 800 and 900 nm also provided sensitive detection of N stress. In 1993, an inexpensive photometric cell, which has peak sensitivity to light centered at 550 nm, was also used to measure reflected radiation from a corn canopy. Photometric cell readings correlated with relative grain yield (P < 0.001, r 2 = 0.74), but more research will be required to develop procedures to account for varying daylight conditions. These results provide information needed for the development of variable-rate fertilizer N application technology. (author)

  14. Herbivory alters plant carbon assimilation, patterns of biomass allocation and nitrogen use efficiency

    Science.gov (United States)

    Peschiutta, María Laura; Scholz, Fabián Gustavo; Goldstein, Guillermo; Bucci, Sandra Janet

    2018-01-01

    Herbivory can trigger physiological processes resulting in leaf and whole plant functional changes. The effects of chronic infestation by an insect on leaf traits related to carbon and nitrogen economy in three Prunus avium cultivars were assessed. Leaves from non-infested trees (control) and damaged leaves from infested trees were selected. The insect larvae produce skeletonization of the leaves leaving relatively intact the vein network of the eaten leaves and the abaxial epidermal tissue. At the leaf level, nitrogen content per mass (Nmass) and per area (Narea), net photosynthesis per mass (Amass) and per area (Aarea), photosynthetic nitrogen-use efficiency (PNUE), leaf mass per area (LMA) and total leaf phenols content were measured in the three cultivars. All cultivars responded to herbivory in a similar fashion. The Nmass, Amass, and PNUE decreased, while LMA and total content of phenols increased in partially damaged leaves. Increases in herbivore pressure resulted in lower leaf size and total leaf area per plant across cultivars. Despite this, stem cumulative growth tended to increase in infected plants suggesting a change in the patterns of biomass allocation and in resources sequestration elicited by herbivory. A larger N investment in defenses instead of photosynthetic structures may explain the lower PNUE and Amass observed in damaged leaves. Some physiological changes due to herbivory partially compensate for the cost of leaf removal buffering the carbon economy at the whole plant level.

  15. Simulation of Soil Nitrogen Content Effect on Weed Seedling Emergence Pattern in Moldavian Balm (Dracocephalum moldavica L.

    Directory of Open Access Journals (Sweden)

    Afsaneh Moradian

    2016-06-01

    Full Text Available The soil nitrogen content with impact on weed seed dormancy breaking can change their seedling emergence pattern. A trial was carried out in 2014 to predict seedling emergence of Xanthium strumarium, Chenopodium album, Echinocloa cruss-galli,  Amaranthus retroflexus andConvolvulus arvensis,  and to evaluate the impact of soil nitrogen content (Control with 0.07% nitrogen, adding 50 and 100 kg N.ha-1 on seedling emergence pattern in Moldavian balm. The experimental design was randomized complete block design. Weed seedlings were counted and removed on a weekly basis throughout the season. The data were converted to percent of cumulative emergence and percentage of cumulative emergence values was compared with thermal time using Gompertz modified functions. The all species showed different emergence patterns and thermal time required for the onset of emergence. The results also showed that the emergence patterns of Chenopodium and Convolvulus  not affected by nitrogen treatments. However, soil nitrogen content significantly changed emergence patterns of A. retroflexus, E. cruss-galli and X. strumarium. According to our model, A. retroflexus, E. cruss-galli and X. strumarium emergence, respectively, started at 237, 96 and 63 TT with 50 kg additional nitrogen.ha-1, while the respective value in control were 340, 117 and 135, respectively. Due to influence of soil nitrogen on emergence pattern of A. retroflexus, E. cruss-galli and X. strumarium, soil nitrogen content should be considered as an important parameter in the modeling of these weed seedling emergence.

  16. Post-fire spatial patterns of soil nitrogen mineralization and microbial abundance.

    Directory of Open Access Journals (Sweden)

    Erica A H Smithwick

    Full Text Available Stand-replacing fires influence soil nitrogen availability and microbial community composition, which may in turn mediate post-fire successional dynamics and nutrient cycling. However, fires create patchiness at both local and landscape scales and do not result in consistent patterns of ecological dynamics. The objectives of this study were to (1 quantify the spatial structure of microbial communities in forest stands recently affected by stand-replacing fire and (2 determine whether microbial variables aid predictions of in situ net nitrogen mineralization rates in recently burned stands. The study was conducted in lodgepole pine (Pinus contorta var. latifolia and Engelmann spruce/subalpine fir (Picea engelmannii/Abies lasiocarpa forest stands that burned during summer 2000 in Greater Yellowstone (Wyoming, USA. Using a fully probabilistic spatial process model and Bayesian kriging, the spatial structure of microbial lipid abundance and fungi-to-bacteria ratios were found to be spatially structured within plots two years following fire (for most plots, autocorrelation range varied from 1.5 to 10.5 m. Congruence of spatial patterns among microbial variables, in situ net N mineralization, and cover variables was evident. Stepwise regression resulted in significant models of in situ net N mineralization and included variables describing fungal and bacterial abundance, although explained variance was low (R²<0.29. Unraveling complex spatial patterns of nutrient cycling and the biotic factors that regulate it remains challenging but is critical for explaining post-fire ecosystem function, especially in Greater Yellowstone, which is projected to experience increased fire frequencies by mid 21(st Century.

  17. Nitrate and ammonium lead to distinct global dynamic phosphorylation patterns when resupplied to nitrogen-starved Arabidopsis seedlings.

    Science.gov (United States)

    Engelsberger, Wolfgang R; Schulze, Waltraud X

    2012-03-01

    Nitrogen is an essential macronutrient for plant growth and development. Inorganic nitrogen and its assimilation products control various metabolic, physiological and developmental processes. Although the transcriptional responses induced by nitrogen have been extensively studied in the past, our work here focused on the discovery of candidate proteins for regulatory events that are complementary to transcriptional changes. Most signaling pathways involve modulation of protein abundance and/or activity by protein phosphorylation. Therefore, we analyzed the dynamic changes in protein phosphorylation in membrane and soluble proteins from plants exposed to rapid changes in nutrient availability over a time course of 30 min. Plants were starved of nitrogen and subsequently resupplied with nitrogen in the form of nitrate or ammonium. Proteins with maximum change in their phosphorylation level at up to 5 min after nitrogen resupply (fast responses) included GPI-anchored proteins, receptor kinases and transcription factors, while proteins with maximum change in their phosphorylation level after 10 min of nitrogen resupply (late responses) included proteins involved in protein synthesis and degradation, as well as proteins with functions in central metabolism and hormone metabolism. Resupply of nitrogen in the form of nitrate or ammonium resulted in distinct phosphorylation patterns, mainly of proteins with signaling functions, transcription factors and transporters. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

  18. Temporal components of the motor patterns expressed by the human spinal cord reflect foot kinematics.

    Science.gov (United States)

    Ivanenko, Yuri P; Grasso, Renato; Zago, Myrka; Molinari, Marco; Scivoletto, Giorgio; Castellano, Vincenzo; Macellari, Velio; Lacquaniti, Francesco

    2003-11-01

    What are the building blocks with which the human spinal cord constructs the motor patterns of locomotion? In principle, they could correspond to each individual activity pattern in dozens of different muscles. Alternatively, there could exist a small set of constituent temporal components that are common to all activation patterns and reflect global kinematic goals. To address this issue, we studied patients with spinal injury trained to step on a treadmill with body weight support. Patients learned to produce foot kinematics similar to that of healthy subjects but with activity patterns of individual muscles generally different from the control group. Hidden in the muscle patterns, we found a basic set of five temporal components, whose flexible combination accounted for the wide range of muscle patterns recorded in both controls and patients. Furthermore, two of the components were systematically related to foot kinematics across different stepping speeds and loading conditions. We suggest that the components are related to control signals output by spinal pattern generators, normally under the influence of descending and afferent inputs.

  19. Wood nitrogen concentrations in tropical trees: phylogenetic patterns and ecological correlates.

    Science.gov (United States)

    Martin, Adam R; Erickson, David L; Kress, W John; Thomas, Sean C

    2014-11-01

    In tropical and temperate trees, wood chemical traits are hypothesized to covary with species' life-history strategy along a 'wood economics spectrum' (WES), but evidence supporting these expected patterns remains scarce. Due to its role in nutrient storage, we hypothesize that wood nitrogen (N) concentration will covary along the WES, being higher in slow-growing species with high wood density (WD), and lower in fast-growing species with low WD. In order to test this hypothesis we quantified wood N concentrations in 59 Panamanian hardwood species, and used this dataset to examine ecological correlates and phylogenetic patterns of wood N. Wood N varied > 14-fold among species between 0.04 and 0.59%; closely related species were more similar in wood N than expected by chance. Wood N was positively correlated with WD, and negatively correlated with log-transformed relative growth rates, although these relationships were relatively weak. We found evidence for co-evolution between wood N and both WD and log-transformed mortality rates. Our study provides evidence that wood N covaries with tree life-history parameters, and that these patterns consistently co-evolve in tropical hardwoods. These results provide some support for the hypothesized WES, and suggest that wood is an increasingly important N pool through tropical forest succession. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  20. Widespread correlation patterns of fMRI signal across visual cortex reflect eccentricity organization

    Science.gov (United States)

    Arcaro, Michael J; Honey, Christopher J; Mruczek, Ryan EB; Kastner, Sabine; Hasson, Uri

    2015-01-01

    The human visual system can be divided into over two-dozen distinct areas, each of which contains a topographic map of the visual field. A fundamental question in vision neuroscience is how the visual system integrates information from the environment across different areas. Using neuroimaging, we investigated the spatial pattern of correlated BOLD signal across eight visual areas on data collected during rest conditions and during naturalistic movie viewing. The correlation pattern between areas reflected the underlying receptive field organization with higher correlations between cortical sites containing overlapping representations of visual space. In addition, the correlation pattern reflected the underlying widespread eccentricity organization of visual cortex, in which the highest correlations were observed for cortical sites with iso-eccentricity representations including regions with non-overlapping representations of visual space. This eccentricity-based correlation pattern appears to be part of an intrinsic functional architecture that supports the integration of information across functionally specialized visual areas. DOI: http://dx.doi.org/10.7554/eLife.03952.001 PMID:25695154

  1. A word-count approach to analyze linguistic patterns in the reflective writings of medical students

    Directory of Open Access Journals (Sweden)

    Chi-Wei Lin

    2016-02-01

    Full Text Available Background: Teaching reflection and administering reflective writing assignments to students are widely practiced and discussed in medical education and health professional education. However, little is known about how medical students use language to construct their narratives. Exploring students’ linguistic patterns in their reflective writings can facilitate understanding the scope and facets of their reflections and their representational or communication approaches to share their experiences. Moreover, research findings regarding gender differences in language use are inconsistent. Therefore, we attempted to examine how females and males differ in their use of words in reflective writing within our research circumstance to detect the unique and gender-specific approaches to learning and their applications. Methods: We analyzed the linguistic profiles of psychological process categories in the reflective writings of medical students and examined the difference in word usage between male and female medical students. During the first year of a clinical rotation, 60 fifth-year medical students wrote reflective narratives regarding pediatric patients and the psychosocial challenges faced by the patients and their family members. The narratives were analyzed using the Chinese version of Linguistic Inquiry and Word Count (CLIWC, a text analysis software program. Multivariate procedures were applied for statistical analysis. Results: Cognitive words were most pervasive, averaging 22.16%, whereas perceptual words (2.86% were least pervasive. Female students used more words related to positive emotions and sadness than did male students. The male students exceeded the female students only in the space category. The major limitation of this study is that CLIWC cannot directly acquire contextual text meanings; therefore, depending on the research topic, further qualitative study of the given texts might be necessary. Conclusions: To enhance students

  2. Mineralogical impact on long-term patterns of soil nitrogen and phosphorus enzyme activities

    Science.gov (United States)

    Mikutta, Robert; Turner, Stephanie; Meyer-Stüve, Sandra; Guggenberger, Georg; Dohrmann, Reiner; Schippers, Axel

    2014-05-01

    Soil chronosequences provide a unique opportunity to study microbial activity over time in mineralogical diverse soils of different ages. The main objective of this study was to test the effect of mineralogical properties, nutrient and organic matter availability over whole soil pro-files on the abundance and activity of the microbial communities. We focused on microbio-logical processes involved in nitrogen and phosphorus cycling at the 120,000-year Franz Josef soil chronosequence. Microbial abundances (microbial biomass and total cell counts) and enzyme activities (protease, urease, aminopeptidase, and phosphatase) were determined and related to nutrient contents and mineralogical soil properties. Both, microbial abundances and enzyme activities decreased with soil depth at all sites. In the organic layers, microbial biomass and the activities of N-hydrolyzing enzymes showed their maximum at the intermediate-aged sites, corresponding to a high aboveground biomass. In contrast, the phosphatase activity increased with site age. The activities of N-hydrolyzing enzymes were positively correlated with total carbon and nitrogen contents, whereas the phosphatase activity was negatively correlated with the phosphorus content. In the mineral soil, the enzyme activities were generally low, thus reflecting the presence of strongly sorbing minerals. Sub-strate-normalized enzyme activities correlated negatively to clay content as well as poorly crystalline Al and Fe oxyhydroxides, supporting the view that the evolution of reactive sec-ondary mineral phases alters the activity of the microbial communities by constraining sub-strate availability. Our data suggest a strong mineralogical influence on nutrient cycling par-ticularly in subsoil environments.

  3. The long-term impact of urbanization on nitrogen patterns and dynamics in Shanghai, China

    International Nuclear Information System (INIS)

    Gu Baojing; Dong Xiaoli; Peng Changhui; Luo Weidong; Chang Jie; Ge Ying

    2012-01-01

    Urbanization is an important process that alters the regional and global nitrogen biogeochemistry. In this study, we test how long-term urbanization (1952–2004) affects the nitrogen flows, emissions and drivers in the Greater Shanghai Area (GSA) based on the coupled human and natural systems (CHANS) approach. Results show that: (1) total nitrogen input to the GSA increased from 57.7 to 587.9 Gg N yr −1 during the period 1952–2004, mainly attributing to fossil fuel combustion (43%), Haber–Bosch nitrogen fixation (31%), and food/feed import (26%); (2) per capita nitrogen input increased from 13.5 to 45.7 kg N yr −1 , while per gross domestic product (GDP) nitrogen input reduced from 22.2 to 0.9 g N per Chinese Yuan, decoupling of nitrogen with GDP; (3) emissions of reactive nitrogen to the environment transformed from agriculture dominated to industry and human living dominated, especially for air pollution. This study provides decision-makers a novel view of nitrogen management. - Highlights: ► Major Nr emission source shifts from agriculture to industry alongside urbanization. ► Decoupling of nitrogen with GDP and urban expansion arises alongside urbanization. ► Nitrogen fluxes increase with population growth and living standard promotion. - Major nitrogen emission source shifts from agriculture to industry and human, and decoupling of nitrogen with GDP and urban expansion arises alongside urbanization.

  4. Arabidopsis roots and shoots show distinct temporal adaptation patterns toward nitrogen starvation.

    Science.gov (United States)

    Krapp, Anne; Berthomé, Richard; Orsel, Mathilde; Mercey-Boutet, Stéphanie; Yu, Agnes; Castaings, Loren; Elftieh, Samira; Major, Hilary; Renou, Jean-Pierre; Daniel-Vedele, Françoise

    2011-11-01

    Nitrogen (N) is an essential macronutrient for plants. N levels in soil vary widely, and plants have developed strategies to cope with N deficiency. However, the regulation of these adaptive responses and the coordinating signals that underlie them are still poorly understood. The aim of this study was to characterize N starvation in adult Arabidopsis (Arabidopsis thaliana) plants in a spatiotemporal manner by an integrative, multilevel global approach analyzing growth, metabolites, enzyme activities, and transcript levels. We determined that the remobilization of N and carbon compounds to the growing roots occurred long before the internal N stores became depleted. A global metabolite analysis by gas chromatography-mass spectrometry revealed organ-specific differences in the metabolic adaptation to complete N starvation, for example, for several tricarboxylic acid cycle intermediates, but also for carbohydrates, secondary products, and phosphate. The activities of central N metabolism enzymes and the capacity for nitrate uptake adapted to N starvation by favoring N remobilization and by increasing the high-affinity nitrate uptake capacity after long-term starvation. Changes in the transcriptome confirmed earlier studies and added a new dimension by revealing specific spatiotemporal patterns and several unknown N starvation-regulated genes, including new predicted small RNA genes. No global correlation between metabolites, enzyme activities, and transcripts was evident. However, this multilevel spatiotemporal global study revealed numerous new patterns of adaptation mechanisms to N starvation. In the context of a sustainable agriculture, this work will give new insight for the production of crops with increased N use efficiency.

  5. Reflections

    Directory of Open Access Journals (Sweden)

    Joanne Embree

    2001-01-01

    Full Text Available Ideally, editorials are written one to two months before publication in the Journal. It was my turn to write this one. I had planned to write the first draft the evening after my clinic on Tuesday, September 11. It didn't get done that night or during the next week. Somehow, the topic that I had originally chosen just didn't seem that important anymore as I, along my friends and colleagues, reflected on the changes that the events of that day were likely to have on our lives.

  6. Successional patterns of key genes and processes involved in the microbial nitrogen cycle in a salt marsh chronosequence

    NARCIS (Netherlands)

    Salles, Joana Falcao; Cassia Pereira e Silva , de Michele; Dini-Andreote, Francisco; Dias, Armando C. F.; Guillaumaud, Nadine; Poly, Franck; van Elsas, Jan Dirk

    Here, we investigated the patterns of microbial nitrogen cycling communities along a chronosequence of soil development in a salt marsh. The focus was on the abundance and structure of genes involved in N fixation (nifH), bacterial and archaeal ammonium oxidation (amoA; AOB and AOA), and the

  7. Converging patterns of vertical variability in leaf morphology and nitrogen across seven Eucalyptus plantations in Brazil and Hawaii, USA

    Science.gov (United States)

    Adam P. Coble; Alisha Autio; Molly A. Cavaleri; Dan Binkley; Michael G. Ryan

    2014-01-01

    Across sites in Brazil and Hawaii, LMA and Nmass were strongly correlated with height and shade index, respectively, which may help simplify canopy function modeling of Eucalyptus plantations. Abstract Within tree canopies, leaf mass per area (LMA) and leaf nitrogen per unit area (Narea) commonly increase with height. Previous research has suggested that these patterns...

  8. Commercial and home-made nitrogen modified titanias. A short reflection about the advantageous/disadvantageous properties of nitrogen doping in the frame of their applicability

    Science.gov (United States)

    Pap, Zs.; Mogyorósi, K.; Veréb, G.; Dombi, A.; Hernádi, K.; Danciu, V.; Baia, L.

    2014-09-01

    As visible light driven photocatalysis became more and more intensively studied, the first commercial products showed up on the market. Simultaneously controversial results appeared in the literature generating an intensive debate regarding the advantages and draw-backs of nitrogen doping of titania. Hence, the present work focuses on two commercially available and four sol-gel made nitrogen modified titania powders regarding their structure and activity. It is demonstrated that the interstitial nitrogen entities “leak out” from the catalysts if the material is irradiated with UV light, while substitutional nitrogen remains stable. However, the latter one was proven to be less important in the photocatalytic point of view. These observations were also valid in the case of sol-gel made nitrogen modified titanias. Furthermore, the results obtained after applying different spectroscopic methods (IR, XPS and DRS) shown that the yellow color of the titanias, does not necessary mean that a successful doping is achieved.

  9. Changes in vertical distribution of spectral reflectance within Spring barley canopy as an indicator of nitrogen nutrition, canopy structure and yield parametrs

    Czech Academy of Sciences Publication Activity Database

    Klem, Karel; Rajsnerová, Petra; Novotná, Kateřina; Míša, P.; Křen, J.

    2014-01-01

    Roč. 60, č. 2 (2014), s. 50-59 ISSN 0551-3677 R&D Projects: GA MZe QI111A133; GA TA ČR TA02010780 Institutional support: RVO:67179843 Keywords : Hordeum vulgare * spectral reflectance * vertical gradient * vegetation indices * nitrogen * grain yield * protein content Subject RIV: GC - Agronomy

  10. Global patterns and substrate-based mechanisms of the terrestrial nitrogen cycle.

    Science.gov (United States)

    Niu, Shuli; Classen, Aimée T; Dukes, Jeffrey S; Kardol, Paul; Liu, Lingli; Luo, Yiqi; Rustad, Lindsey; Sun, Jian; Tang, Jianwu; Templer, Pamela H; Thomas, R Quinn; Tian, Dashuan; Vicca, Sara; Wang, Ying-Ping; Xia, Jianyang; Zaehle, Sönke

    2016-06-01

    Nitrogen (N) deposition is impacting the services that ecosystems provide to humanity. However, the mechanisms determining impacts on the N cycle are not fully understood. To explore the mechanistic underpinnings of N impacts on N cycle processes, we reviewed and synthesised recent progress in ecosystem N research through empirical studies, conceptual analysis and model simulations. Experimental and observational studies have revealed that the stimulation of plant N uptake and soil retention generally diminishes as N loading increases, while dissolved and gaseous losses of N occur at low N availability but increase exponentially and become the dominant fate of N at high loading rates. The original N saturation hypothesis emphasises sequential N saturation from plant uptake to soil retention before N losses occur. However, biogeochemical models that simulate simultaneous competition for soil N substrates by multiple processes match the observed patterns of N losses better than models based on sequential competition. To enable better prediction of terrestrial N cycle responses to N loading, we recommend that future research identifies the response functions of different N processes to substrate availability using manipulative experiments, and incorporates the measured N saturation response functions into conceptual, theoretical and quantitative analyses. © 2016 John Wiley & Sons Ltd/CNRS.

  11. Nitrogen use efficiency and crop production: Patterns of regional variation in the United States, 1987-2012.

    Science.gov (United States)

    Swaney, Dennis P; Howarth, Robert W; Hong, Bongghi

    2018-04-17

    National-level summaries of crop production and nutrient use efficiency, important for international comparisons, only partially elucidate agricultural dynamics within a country. Agricultural production and associated environmental impacts in large countries vary significantly because of regional differences in crops, climate, resource use and production practices. Here, we review patterns of regional crop production, nitrogen use efficiency (NUE), and major inputs of nitrogen to US crops over 1987-2012, based on the Farm Resource Regions developed by the Economic Research Service (USDA-ERS). Across the US, NUE generally decreased over time over the period studied, mainly due to increased use in mineral N fertilizer above crop N requirements. The Heartland region dominates production of major crops and thus tends to drive national patterns, showing linear response of crop production to nitrogen inputs broadly consistent with an earlier analysis of global patterns of country-scale data by Lassaletta et al. (2014). Most other regions show similar responses, but the Eastern Uplands region shows a negative response to nitrogen inputs, and the Southern Seaboard shows no significant relationship. The regional differences appear as two branches in the response of aggregate production to N inputs on a cropland area basis, but not on a total area basis, suggesting that the type of scaling used is critical under changing cropland area. Nitrogen use efficiency (NUE) is positively associated with fertilizer as a percentage of N inputs in four regions, and all regions considered together. NUE is positively associated with crop N fixation in all regions except Northern Great Plains. It is negatively associated with manure (livestock excretion); in the US, manure is still treated largely as a waste to be managed rather than a nutrient resource. This significant regional variation in patterns of crop production and NUE vs N inputs, has implications for environmental quality and

  12. Protein functional features are reflected in the patterns of mRNA translation speed.

    Science.gov (United States)

    López, Daniel; Pazos, Florencio

    2015-07-09

    The degeneracy of the genetic code makes it possible for the same amino acid string to be coded by different messenger RNA (mRNA) sequences. These "synonymous mRNAs" may differ largely in a number of aspects related to their overall translational efficiency, such as secondary structure content and availability of the encoded transfer RNAs (tRNAs). Consequently, they may render different yields of the translated polypeptides. These mRNA features related to translation efficiency are also playing a role locally, resulting in a non-uniform translation speed along the mRNA, which has been previously related to some protein structural features and also used to explain some dramatic effects of "silent" single-nucleotide-polymorphisms (SNPs). In this work we perform the first large scale analysis of the relationship between three experimental proxies of mRNA local translation efficiency and the local features of the corresponding encoded proteins. We found that a number of protein functional and structural features are reflected in the patterns of ribosome occupancy, secondary structure and tRNA availability along the mRNA. One or more of these proxies of translation speed have distinctive patterns around the mRNA regions coding for certain protein local features. In some cases the three patterns follow a similar trend. We also show specific examples where these patterns of translation speed point to the protein's important structural and functional features. This support the idea that the genome not only codes the protein functional features as sequences of amino acids, but also as subtle patterns of mRNA properties which, probably through local effects on the translation speed, have some consequence on the final polypeptide. These results open the possibility of predicting a protein's functional regions based on a single genomic sequence, and have implications for heterologous protein expression and fine-tuning protein function.

  13. The long-term impact of urbanization on nitrogen patterns and dynamics in Shanghai, China.

    Science.gov (United States)

    Gu, Baojing; Dong, Xiaoli; Peng, Changhui; Luo, Weidong; Chang, Jie; Ge, Ying

    2012-12-01

    Urbanization is an important process that alters the regional and global nitrogen biogeochemistry. In this study, we test how long-term urbanization (1952-2004) affects the nitrogen flows, emissions and drivers in the Greater Shanghai Area (GSA) based on the coupled human and natural systems (CHANS) approach. Results show that: (1) total nitrogen input to the GSA increased from 57.7 to 587.9 Gg N yr(-1) during the period 1952-2004, mainly attributing to fossil fuel combustion (43%), Haber-Bosch nitrogen fixation (31%), and food/feed import (26%); (2) per capita nitrogen input increased from 13.5 to 45.7 kg N yr(-1), while per gross domestic product (GDP) nitrogen input reduced from 22.2 to 0.9 g N per Chinese Yuan, decoupling of nitrogen with GDP; (3) emissions of reactive nitrogen to the environment transformed from agriculture dominated to industry and human living dominated, especially for air pollution. This study provides decision-makers a novel view of nitrogen management. Copyright © 2012 Elsevier Ltd. All rights reserved.

  14. Distribution patterns of nitrogen micro-cycle functional genes and their quantitative coupling relationships with nitrogen transformation rates in a biotrickling filter.

    Science.gov (United States)

    Wang, Honglei; Ji, Guodong; Bai, Xueyuan

    2016-06-01

    The present study explored the distribution patterns of nitrogen micro-cycle genes and the underlying mechanisms responsible for nitrogen transformation at the molecular level (genes) in a biotrickling filter (biofilter). The biofilter achieved high removal efficiencies for ammonium (NH4(+)-N) (80-94%), whereas nitrate accumulated at different levels under a progressive NH4(+)-N load. Combined analyses revealed the anammox, nas, napA, narG, nirS, and nxrA genes were the dominant enriched genes in different treatment layers. The presence of simultaneous nitrification, ammonium oxidation (anammox), and dissimilatory nitrate reduction to ammonium (DNRA) were the primary factors accounted for the robust NH4(+)-N treatment performance. The presence of DNRA, nitrification, and denitrification was determined to be a pivotal pathway that contributed to the nitrate accumulation in the biofilter. The enrichment of functional genes at different depth gradients and the multi-path coupled cooperation at the functional gene level are conducive to achieving complete nitrogen removal. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Atmospheric nitrogen deposition in the Yangtze River basin: Spatial pattern and source attribution

    International Nuclear Information System (INIS)

    Xu, Wen; Zhao, Yuanhong; Liu, Xuejun; Dore, Anthony J.; Zhang, Lin; Liu, Lei; Cheng, Miaomiao

    2018-01-01

    The Yangtze River basin is one of the world's hotspots for nitrogen (N) deposition and likely plays an important role in China's riverine N output. Here we constructed a basin-scale total dissolved inorganic N (DIN) deposition (bulk plus dry) pattern based on published data at 100 observational sites between 2000 and 2014, and assessed the relative contributions of different reactive N (N r ) emission sectors to total DIN deposition using the GEOS-Chem model. Our results show a significant spatial variation in total DIN deposition across the Yangtze River basin (33.2 kg N ha −1 yr −1 on average), with the highest fluxes occurring mainly in the central basin (e.g., Sichuan, Hubei and Hunan provinces, and Chongqing municipality). This indicates that controlling N deposition should build on mitigation strategies according to local conditions, namely, implementation of stricter control of N r emissions in N deposition hotspots but moderate control in the areas with low N deposition levels. Total DIN deposition in approximately 82% of the basin area exceeded the critical load of N deposition for semi-natural ecosystems along the basin. On the basin scale, the dominant source of DIN deposition is fertilizer use (40%) relative to livestock (11%), industry (13%), power plant (9%), transportation (9%), and others (18%, which is the sum of contributions from human waste, residential activities, soil, lighting and biomass burning), suggesting that reducing NH 3 emissions from improper fertilizer (including chemical and organic fertilizer) application should be a priority in curbing N deposition. This, together with distinct spatial variations in emission sector contributions to total DIN deposition also suggest that, in addition to fertilizer, major emission sectors in different regions of the basin should be considered when developing synergistic control measures. - Highlights: • Total DIN deposition fluxes showed a significant spatial variation in the

  16. Sample preparation for total reflection X-ray fluorescence analysis using resist pattern technique

    Science.gov (United States)

    Tsuji, K.; Yomogita, N.; Konyuba, Y.

    2018-06-01

    A circular resist pattern layer with a diameter of 9 mm was prepared on a glass substrate (26 mm × 76 mm; 1.5 mm thick) for total reflection X-ray fluorescence (TXRF) analysis. The parallel cross pattern was designed with a wall thickness of 10 μm, an interval of 20 μm, and a height of 1.4 or 0.8 μm. This additional resist layer did not significantly increase background intensity on the XRF peaks in TXRF spectra. Dotted residue was obtained from a standard solution (10 μL) containing Ti, Cr, Ni, Pb, and Ga, each at a final concentration of 10 ppm, on a normal glass substrate with a silicone coating layer. The height of the residue was more than 100 μm, where self-absorption in the large residue affected TXRF quantification (intensity relative standard deviation (RSD): 12-20%). In contrast, from a droplet composed of a small volume of solution dropped and cast on the resist pattern structure, the obtained residue was not completely film but a film-like residue with a thickness less than 1 μm, where self-absorption was not a serious problem. In the end, this sample preparation was demonstrated to improve TXRF quantification (intensity RSD: 2-4%).

  17. Contrasting PCB bioaccumulation patterns among Lake Huron lake trout reflect basin-specific ecology.

    Science.gov (United States)

    Paterson, Gordon; Ryder, Mark; Drouillard, Ken G; Haffner, G Douglas

    2016-01-01

    This study collected multiple age classes of lake trout from Lake Huron's Main Basin, Georgian Bay, and North Channel regions to compare and contrast top predator polychlorinated biphenyl (PCB) bioaccumulation patterns in separate compartments of the same ecosystem. Sum PCB concentrations were highest for Main Basin (260 ± 24.9 ng g(-1) wet wt) fish, followed by Georgian Bay (74.6 ± 16.2 ng g(-1) ) and North Channel (42.0 ± 3.3 ng g(-1)) fish. Discriminant functions analysis of lake trout PCB profiles and stable carbon (δ(13)C) and nitrogen (δ(15)N) isotope values clearly distinguished fish by location, indicating high degrees of basin fidelity throughout their lifetimes in addition to highly contrasting PCB bioaccumulation profiles. These unique profiles were not attributable to significant differences in lake trout lipid contents (p = 0.856) or trophic position (δ(15)N; p = 0.334), with rainbow smelt representing the primary prey across the basins. Furthermore, significant differences were observed among the basins for the relationships between PCB biomagnification factors and hydrophobicity. An empirical model for predicting PCB biomagnification in Lake Huron lake trout indicated that basin-specific population growth rates and prey abundances were significant for explaining these contrasting patterns of PCB bioaccumulation. The results of the present study are fundamental for understanding the role of ecology in legacy persistent organic pollutant (POP) bioaccumulation. Specifically, ecosystem characteristics such as prey abundances, foraging ecology, and ultimately consumer growth can regulate the variability of legacy POP bioaccumulation as observed within and among a wide range of freshwater ecosystems. © 2015 SETAC.

  18. Laser reflection spot as a pattern in a diamond coating – a microscopic study

    Directory of Open Access Journals (Sweden)

    GORDANA S. RISTIĆ

    2009-07-01

    Full Text Available Diamond coatings were deposited by the synchronous and coupled action of a hot filament CVD method and a pulsed CO2 laser in spectro-absorbing and spectro-non-absorbing diamond precursor atmospheres. The obtained coatings were structured/patterned, i.e., they were comprised of uncovered, bare locations. An extra effect observed only in the spectro-active diamond precursor atmosphere was the creation of another laser spot in the coating – a reflection spot. In order to establish the practical usability of the latter one, extensive microscopic investigations were performed with consideration of the morphology changes in the spot of the direct laser beam. Normal incidence SEM images of this spot showed a smooth surface, without any pulse radiation damage. AFM imaging revealed the actual surface condition and gave precise data on the surface characteristics.

  19. Atmospheric nitrogen deposition in the Yangtze River basin: Spatial pattern and source attribution.

    Science.gov (United States)

    Xu, Wen; Zhao, Yuanhong; Liu, Xuejun; Dore, Anthony J; Zhang, Lin; Liu, Lei; Cheng, Miaomiao

    2018-01-01

    The Yangtze River basin is one of the world's hotspots for nitrogen (N) deposition and likely plays an important role in China's riverine N output. Here we constructed a basin-scale total dissolved inorganic N (DIN) deposition (bulk plus dry) pattern based on published data at 100 observational sites between 2000 and 2014, and assessed the relative contributions of different reactive N (N r ) emission sectors to total DIN deposition using the GEOS-Chem model. Our results show a significant spatial variation in total DIN deposition across the Yangtze River basin (33.2 kg N ha -1 yr -1 on average), with the highest fluxes occurring mainly in the central basin (e.g., Sichuan, Hubei and Hunan provinces, and Chongqing municipality). This indicates that controlling N deposition should build on mitigation strategies according to local conditions, namely, implementation of stricter control of N r emissions in N deposition hotspots but moderate control in the areas with low N deposition levels. Total DIN deposition in approximately 82% of the basin area exceeded the critical load of N deposition for semi-natural ecosystems along the basin. On the basin scale, the dominant source of DIN deposition is fertilizer use (40%) relative to livestock (11%), industry (13%), power plant (9%), transportation (9%), and others (18%, which is the sum of contributions from human waste, residential activities, soil, lighting and biomass burning), suggesting that reducing NH 3 emissions from improper fertilizer (including chemical and organic fertilizer) application should be a priority in curbing N deposition. This, together with distinct spatial variations in emission sector contributions to total DIN deposition also suggest that, in addition to fertilizer, major emission sectors in different regions of the basin should be considered when developing synergistic control measures. Copyright © 2017. Published by Elsevier Ltd.

  20. Activity pattern and personal exposure to nitrogen dioxide in indoor and outdoor microenvironments.

    Science.gov (United States)

    Kornartit, C; Sokhi, R S; Burton, M A; Ravindra, Khaiwal

    2010-01-01

    People are exposed to air pollution from a range of indoor and outdoor sources. Concentrations of nitrogen dioxide (NO(2)), which is hazardous to health, can be significant in both types of environments. This paper reports on the measurement and analysis of indoor and outdoor NO(2) concentrations and their comparison with measured personal exposure in various microenvironments during winter and summer seasons. Furthermore, the relationship between NO(2) personal exposure in various microenvironments and including activities patterns were also studied. Personal, indoor microenvironments and outdoor measurements of NO(2) levels were conducted using Palmes tubes for 60 subjects. The results showed significant differences in indoor and outdoor NO(2) concentrations in winter but not for summer. In winter, indoor NO(2) concentrations were found to be strongly correlated with personal exposure levels. NO(2) concentration in houses using a gas cooker was higher in all rooms than those with an electric cooker during the winter campaign, whereas there was no significant difference noticed in summer. The average NO(2) levels in kitchens with a gas cooker were twice as high as those with an electric cooker, with no significant difference in the summer period. A time-weighted average personal exposure was calculated and compared with measured personal exposures in various indoor microenvironments (e.g. front doors, bedroom, living room and kitchen); including non-smokers, passive smokers and smoker. The estimated results were closely correlated, but showed some underestimation of the measured personal exposures to NO(2) concentrations. Interestingly, for our particular study higher NO(2) personal exposure levels were found during summer (14.0+/-1.5) than winter (9.5+/-2.4).

  1. Using pattern recognition to automatically localize reflection hyperbolas in data from ground penetrating radar

    Science.gov (United States)

    Maas, Christian; Schmalzl, Jörg

    2013-08-01

    Ground Penetrating Radar (GPR) is used for the localization of supply lines, land mines, pipes and many other buried objects. These objects can be recognized in the recorded data as reflection hyperbolas with a typical shape depending on depth and material of the object and the surrounding material. To obtain the parameters, the shape of the hyperbola has to be fitted. In the last years several methods were developed to automate this task during post-processing. In this paper we show another approach for the automated localization of reflection hyperbolas in GPR data by solving a pattern recognition problem in grayscale images. In contrast to other methods our detection program is also able to immediately mark potential objects in real-time. For this task we use a version of the Viola-Jones learning algorithm, which is part of the open source library "OpenCV". This algorithm was initially developed for face recognition, but can be adapted to any other simple shape. In our program it is used to narrow down the location of reflection hyperbolas to certain areas in the GPR data. In order to extract the exact location and the velocity of the hyperbolas we apply a simple Hough Transform for hyperbolas. Because the Viola-Jones Algorithm reduces the input for the computational expensive Hough Transform dramatically the detection system can also be implemented on normal field computers, so on-site application is possible. The developed detection system shows promising results and detection rates in unprocessed radargrams. In order to improve the detection results and apply the program to noisy radar images more data of different GPR systems as input for the learning algorithm is necessary.

  2. Subtypes of the Type II Pit Pattern Reflect Distinct Molecular Subclasses in the Serrated Neoplastic Pathway.

    Science.gov (United States)

    Aoki, Hironori; Yamamoto, Eiichiro; Yamano, Hiro-O; Sugai, Tamotsu; Kimura, Tomoaki; Tanaka, Yoshihito; Matsushita, Hiro-O; Yoshikawa, Kenjiro; Takagi, Ryo; Harada, Eiji; Nakaoka, Michiko; Yoshida, Yuko; Harada, Taku; Sudo, Gota; Eizuka, Makoto; Yorozu, Akira; Kitajima, Hiroshi; Niinuma, Takeshi; Kai, Masahiro; Nojima, Masanori; Suzuki, Hiromu; Nakase, Hiroshi

    2018-03-15

    Colorectal serrated lesions (SLs) are important premalignant lesions whose clinical and biological features are not fully understood. We aimed to establish accurate colonoscopic diagnosis and treatment of SLs through evaluation of associations among the morphological, pathological, and molecular characteristics of SLs. A total of 388 premalignant and 18 malignant colorectal lesions were studied. Using magnifying colonoscopy, microsurface structures were assessed based on Kudo's pit pattern classification system, and the Type II pit pattern was subcategorized into classical Type II, Type II-Open (Type II-O) and Type II-Long (Type II-L). BRAF/KRAS mutations and DNA methylation of CpG island methylator phenotype (CIMP) markers (MINT1, - 2, - 12, - 31, p16, and MLH1) were analyzed through pyrosequencing. Type II-O was tightly associated with sessile serrated adenoma/polyps (SSA/Ps) with BRAF mutation and CIMP-high. Most lesions with simple Type II or Type II-L were hyperplastic polyps, while mixtures of Type II or Type II-L plus more advanced pit patterns (III/IV) were characteristic of traditional serrated adenomas (TSAs). Type II-positive TSAs frequently exhibited BRAF mutation and CIMP-low, while Type II-L-positive TSAs were tightly associated with KRAS mutation and CIMP-low. Analysis of lesions containing both premalignant and cancerous components suggested Type II-L-positive TSAs may develop into KRAS-mutated/CIMP-low/microsatellite stable cancers, while Type II-O-positive SSA/Ps develop into BRAF-mutated/CIMP-high/microsatellite unstable cancers. These results suggest that Type II subtypes reflect distinct molecular subclasses in the serrated neoplasia pathway and that they could be useful hallmarks for identifying SLs at high risk of developing into CRC.

  3. Do ethnic patterns in cryptorchidism reflect those found in testicular cancer?

    Science.gov (United States)

    Gurney, Jason; Sarfati, Diana; Stanley, James; Studd, Rodney

    2013-11-01

    There are established variations in testicular cancer incidence between ethnic groups within countries. It is currently unclear whether the occurrence of cryptorchidism-a known risk factor for testicular cancer-follows similar patterns. In New Zealand Māori have unusually high rates of testicular cancer compared to individuals of European ancestry. We hypothesized that ethnic trends in the incidence of cryptorchidism would reflect those for testicular cancer in this setting. We followed 318,441 eligible male neonates born in New Zealand between 2000 and 2010 for the incidence of orchiopexy confirmed cryptorchidism and the incidence of known risk factors for cryptorchidism (low birth weight, short gestation, small size for gestational age) using routine maternity, hospitalization and mortality records. Logistic regression was used to calculate odds ratios for the presence of known risk factors for cryptorchidism by ethnic group. Poisson regression was used to calculate relative risk of cryptorchidism by ethnicity, adjusted for risk factors. Ethnic patterns of cryptorchidism incidence in New Zealand closely mirrored those previously observed for testicular cancer. Māori had higher rates of cryptorchidism than all other ethnic groups (adjusted RR 1.2 [95% CI 1.11-1.3]), with Pacific (0.89 [0.8-0.99]) and Asian groups (0.68 [0.59-0.79]) having the lowest rates (European/other, referent). Since the principal risk factors for cryptorchidism are present in utero, the results of the current study strengthen the likelihood that the ethnic patterning of testicular cancer is at least partly due to prenatal risk factors. Copyright © 2013 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  4. Right fusiform response patterns reflect visual object identity rather than semantic similarity.

    Science.gov (United States)

    Bruffaerts, Rose; Dupont, Patrick; De Grauwe, Sophie; Peeters, Ronald; De Deyne, Simon; Storms, Gerrit; Vandenberghe, Rik

    2013-12-01

    We previously reported the neuropsychological consequences of a lesion confined to the middle and posterior part of the right fusiform gyrus (case JA) causing a partial loss of knowledge of visual attributes of concrete entities in the absence of category-selectivity (animate versus inanimate). We interpreted this in the context of a two-step model that distinguishes structural description knowledge from associative-semantic processing and implicated the lesioned area in the former process. To test this hypothesis in the intact brain, multi-voxel pattern analysis was used in a series of event-related fMRI studies in a total of 46 healthy subjects. We predicted that activity patterns in this region would be determined by the identity of rather than the conceptual similarity between concrete entities. In a prior behavioral experiment features were generated for each entity by more than 1000 subjects. Based on a hierarchical clustering analysis the entities were organised into 3 semantic clusters (musical instruments, vehicles, tools). Entities were presented as words or pictures. With foveal presentation of pictures, cosine similarity between fMRI response patterns in right fusiform cortex appeared to reflect both the identity of and the semantic similarity between the entities. No such effects were found for words in this region. The effect of object identity was invariant for location, scaling, orientation axis and color (grayscale versus color). It also persisted for different exemplars referring to a same concrete entity. The apparent semantic similarity effect however was not invariant. This study provides further support for a neurobiological distinction between structural description knowledge and processing of semantic relationships and confirms the role of right mid-posterior fusiform cortex in the former process, in accordance with previous lesion evidence. © 2013.

  5. Regional patterns in foliar 15N across a gradient of nitrogen deposition in the northeastern US

    Science.gov (United States)

    Linda H. Pardo; Steven G. McNulty; Johnny L. Boggs; Sara Duke

    2007-01-01

    Recent studies have demonstrated that natural abundance 15N can be a useful tool for assessing nitrogen saturation, because as nitrification and nitrate loss increase, d15N of foliage and soil also increases. We measured foliar d15N at 11 high-elevation spruce-fir stands along an N deposition gradient...

  6. Canine and incisor microwear in pitheciids and Ateles reflects documented patterns of tooth use.

    Science.gov (United States)

    Delezene, Lucas K; Teaford, Mark F; Ungar, Peter S

    2016-09-01

    Platyrrhine species differ in the extent to and the manner in which they use their incisors and canines during food ingestion. For example, Ateles uses its anterior teeth to process mechanically nondemanding soft fruits, while the sclerocarp-harvesting pitheciids rely extensively on these teeth to acquire and process more demanding foods. Pitheciids themselves vary in anterior tooth use, with the pitheciines (Cacajao, Chiropotes, and Pithecia) noted to use their robust canines in a variety of ways to predate seeds, while Callicebus, which rarely predates seeds, uses its incisors and exceptionally short canines to scrape tough mesocarp from fruits. To investigate the relationship between tooth use and dental wear, microwear textures were investigated for the anterior teeth of these five genera of platyrrhine primates. Using a white light confocal microscope, 12 microwear texture attributes that reflect feature size, anisotropy, density, and complexity were recorded from high-resolution epoxy casts of the incisors and canines of adult wild-collected Brazilian specimens of Ateles, Callicebus, Cacajao, Chiropotes, and Pithecia. Pitheciine canines tend to have deep microwear features and complex, anisotropic microwear textures, while Ateles anterior teeth tend to have very small features, low feature density, and less complex and anisotropic surfaces. Callicebus incisor and canine microwear is generally intermediate in size and complexity between those extremes. These findings align with expectations from reported field observations of tooth use and illustrate the potential for using microwear texture analysis to infer patterns of anterior tooth use in extinct primates. Am J Phys Anthropol 161:6-25, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  7. The quality of school lunch consumed reflects overall eating patterns in 11-16-year-old schoolchildren in Finland.

    Science.gov (United States)

    Tilles-Tirkkonen, Tanja; Pentikäinen, Saara; Lappi, Jenni; Karhunen, Leila; Poutanen, Kaisa; Mykkänen, Hannu

    2011-12-01

    To explore how the quality of school lunch consumed reflected overall eating patterns in school-aged children. Children filled in an Internet-based questionnaire about their eating patterns. The children were then divided into balanced and imbalanced school lunch eaters on the basis of their responses in the questionnaire. A balanced school lunch consisted of, by the definition used in the present study, a main dish, salad and bread. Eleven primary schools and one middle school in eastern Finland. A total of 531 schoolchildren (247 boys and 284 girls) aged 11-16 years. The school lunch was balanced in 46·5% of children. Eating a balanced school lunch was associated with overall healthier eating patterns outside school. Children who ate a balanced school lunch had more regular meal times and consumed healthier snacks. They ate fruit or berries and vegetables, dairy products and wholegrain foods more often, consumed fewer salty snacks, pizzas, meat pies and drank fewer soft drinks and energy drinks. Their eating patterns at home were also healthier, with vegetables being offered at every family dinner and fruit being offered daily, whereas soft drinks were offered seldom. The choices made by children in their school lunch reflect the overall eating patterns among school-aged children. Eating a balanced school lunch is associated with more regular meal patterns, the availability of healthier foods at home and an overall healthier diet, suggesting that healthy eating patterns are learnt at home.

  8. Spatiotemporal patterns and source attribution of nitrogen pollution in a typical headwater agricultural watershed in Southeastern China.

    Science.gov (United States)

    Chen, Wenjun; He, Bin; Nover, Daniel; Duan, Weili; Luo, Chuan; Zhao, Kaiyan; Chen, Wen

    2018-01-01

    Excessive nitrogen (N) discharge from agriculture causes widespread problems in aquatic ecosystems. Knowledge of spatiotemporal patterns and source attribution of N pollution is critical for nutrient management programs but is poorly studied in headwaters with various small water bodies and mini-point pollution sources. Taking a typical small watershed in the low mountains of Southeastern China as an example, N pollution and source attribution were studied for a multipond system around a village using the Hydrological Simulation Program-Fortran (HSPF) model. The results exhibited distinctive spatio-seasonal variations with an overall seriousness rank for the three indicators: total nitrogen (TN) > nitrate/nitrite nitrogen (NO x - -N) > ammonia nitrogen (NH 3 -N), according to the Chinese Surface Water Quality Standard. TN pollution was severe for the entire watershed, while NO x - -N pollution was significant for ponds and ditches far from the village, and the NH 3 -N concentrations were acceptable except for the ponds near the village in summer. Although food and cash crop production accounted for the largest source of N loads, we discovered that mini-point pollution sources, including animal feeding operations, rural residential sewage, and waste, together contributed as high as 47% of the TN and NH 3 -N loads in ponds and ditches. So, apart from eco-fertilizer programs and concentrated animal feeding operations, the importance of environmental awareness building for resource management is highlighted for small farmers in headwater agricultural watersheds. As a first attempt to incorporate multipond systems into the process-based modeling of nonpoint source (NPS) pollution, this work can inform other hydro-environmental studies on scattered and small water bodies. The results are also useful to water quality improvement for entire river basins.

  9. ASSESSING INTRA- AND INTER-FIELD VARIABILITY OF CORN NITROGEN FERTILIZER NEED USING GROUND-BASED REFLECTANCE SENSORS

    Science.gov (United States)

    Since soil types within and between corn (Zea mays L.) fields can be highly variable, the amount of nitrogen (N) provided by those different soil types to support production can also be highly variable. Ideally, the amount of N fertilizer added during a given growing season should be both climate-se...

  10. Diffuse nitrogen loss simulation and impact assessment of stereoscopic agriculture pattern by integrated water system model and consideration of multiple existence forms

    Science.gov (United States)

    Zhang, Yongyong; Gao, Yang; Yu, Qiang

    2017-09-01

    Agricultural nitrogen loss becomes an increasingly important source of water quality deterioration and eutrophication, even threatens water safety for humanity. Nitrogen dynamic mechanism is still too complicated to be well captured at watershed scale due to its multiple existence forms and instability, disturbance of agricultural management practices. Stereoscopic agriculture is a novel agricultural planting pattern to efficiently use local natural resources (e.g., water, land, sunshine, heat and fertilizer). It is widely promoted as a high yield system and can obtain considerable economic benefits, particularly in China. However, its environmental quality implication is not clear. In our study, Qianyanzhou station is famous for its stereoscopic agriculture pattern of Southern China, and an experimental watershed was selected as our study area. Regional characteristics of runoff and nitrogen losses were simulated by an integrated water system model (HEQM) with multi-objective calibration, and multiple agriculture practices were assessed to find the effective approach for the reduction of diffuse nitrogen losses. Results showed that daily variations of runoff and nitrogen forms were well reproduced throughout watershed, i.e., satisfactory performances for ammonium and nitrate nitrogen (NH4-N and NO3-N) loads, good performances for runoff and organic nitrogen (ON) load, and very good performance for total nitrogen (TN) load. The average loss coefficient was 62.74 kg/ha for NH4-N, 0.98 kg/ha for NO3-N, 0.0004 kg/ha for ON and 63.80 kg/ha for TN. The dominating form of nitrogen losses was NH4-N due to the applied fertilizers, and the most dramatic zones aggregated in the middle and downstream regions covered by paddy and orange orchard. In order to control diffuse nitrogen losses, the most effective practices for Qianyanzhou stereoscopic agriculture pattern were to reduce farmland planting scale in the valley by afforestation, particularly for orchard in the

  11. A study on reflection pattern of swells from the shoreline of peninsular India

    Digital Repository Service at National Institute of Oceanography (India)

    Anoop, T.R.; SanilKumar, V.; Johnson, G.

    and tidal current on the reflected waves were examined. For the locations off the west coast of India, seasons have large impact on the reflection coefficient and were relatively less during the monsoon season due to the increase in incident wave energy...

  12. Effects of land-use patterns on in-stream nitrogen in a highly-polluted river basin in Northeast China

    International Nuclear Information System (INIS)

    Bu, Hongmei; Zhang, Yuan; Meng, Wei; Song, Xianfang

    2016-01-01

    This study investigated the effects of land-use patterns on nitrogen pollution in the Haicheng River basin in Northeast China during 2010 by conducting statistical and spatial analyses and by analyzing the isotopic composition of nitrate. Correlation and stepwise regressions indicated that land-use types and landscape metrics were correlated well with most river nitrogen variables and significantly predicted them during different sampling seasons. Built-up land use and shape metrics dominated in predicting nitrogen variables over seasons. According to the isotopic compositions of river nitrate in different zones, the nitrogen sources of the river principally originated from synthetic fertilizer, domestic sewage/manure, soil organic matter, and atmospheric deposition. Isotope mixing models indicated that source contributions of river nitrogen significantly varied from forested headwaters to densely populated towns of the river basin. Domestic sewage/manure was a major contributor to river nitrogen with the proportions of 76.4 ± 6.0% and 62.8 ± 2.1% in residence and farmland-residence zones, respectively. This research suggested that regulating built-up land uses and reducing discharges of domestic sewage and industrial wastewater would be effective methods for river nitrogen control. - Highlights: • Land-use types were correlated well with most nitrogen variables over seasons. • Built-up land dominated in predicting nitrogen variables during different seasons. • Shape metrics predicted most nitrogen variables in different seasons. • Nitrogen sources and their contributions were estimated using nitrate isotopes. • Domestic sewage mainly contributed to river nitrogen pollution in residence zone.

  13. Effects of land-use patterns on in-stream nitrogen in a highly-polluted river basin in Northeast China

    Energy Technology Data Exchange (ETDEWEB)

    Bu, Hongmei, E-mail: buhm2004@163.com [Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China); Zhang, Yuan; Meng, Wei [State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012 (China); Song, Xianfang [Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China)

    2016-05-15

    This study investigated the effects of land-use patterns on nitrogen pollution in the Haicheng River basin in Northeast China during 2010 by conducting statistical and spatial analyses and by analyzing the isotopic composition of nitrate. Correlation and stepwise regressions indicated that land-use types and landscape metrics were correlated well with most river nitrogen variables and significantly predicted them during different sampling seasons. Built-up land use and shape metrics dominated in predicting nitrogen variables over seasons. According to the isotopic compositions of river nitrate in different zones, the nitrogen sources of the river principally originated from synthetic fertilizer, domestic sewage/manure, soil organic matter, and atmospheric deposition. Isotope mixing models indicated that source contributions of river nitrogen significantly varied from forested headwaters to densely populated towns of the river basin. Domestic sewage/manure was a major contributor to river nitrogen with the proportions of 76.4 ± 6.0% and 62.8 ± 2.1% in residence and farmland-residence zones, respectively. This research suggested that regulating built-up land uses and reducing discharges of domestic sewage and industrial wastewater would be effective methods for river nitrogen control. - Highlights: • Land-use types were correlated well with most nitrogen variables over seasons. • Built-up land dominated in predicting nitrogen variables during different seasons. • Shape metrics predicted most nitrogen variables in different seasons. • Nitrogen sources and their contributions were estimated using nitrate isotopes. • Domestic sewage mainly contributed to river nitrogen pollution in residence zone.

  14. Root distribution pattern and nitrogen uptake of some wheat and triticale germplasms in relation to rates and methods of nitrogen application

    International Nuclear Information System (INIS)

    Meena, N.L.; Seth, Jagdish

    1975-01-01

    A field experiment was conducted under irrigated conditions with four germplasms viz. Triticale(70-2), and wheat varieties HD 4502(durum), Kalyan Sona and Moti (aestivums) at the Indian Agricultural Research Institute Farm, New Delhi, during rabi season of 1972-73. The treatments comprised of three rates of nitrogen viz. 0,60 and 120 kg/ha and two methods of nitrogen application viz. (1) soil + foliar and (2) soil. The root distribution of the four germplasms, studied by 32 P injection technique was increased both vertically and horizontally with the addition of nitrogen. Root distribution of triticale was observed to be deep and spreading in habit, while durum proved to be shallow rooted and compact in nature. The total uptake of nitrogen was significantly increased with higher rates of nitrogen in all the germplasms. The maximum uptake of nitrogen was observed in the durum wheat. (author)

  15. Channel Constrained Metalization Patterning of Reflective Backplane Electrodes for Liquid Crystal-on-Silicon Displays

    National Research Council Canada - National Science Library

    Hermanns, Anno

    1997-01-01

    Channel Constrained Metalization (CCM), which employs photoresist patterning to confine electroless metal deposition to selected regions, is an inexpensive alternative to metal sputtering or evaporation...

  16. Analysis of seismic reflectivity and AVO pattern of BSR using OBS data in the southwestern offshore region of Taiwan

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, W.B.; Yang, H.R. [Jinwen Univ. of Science and Technology, Hsintien City, Taipei County, Taiwan (China). Dept. of Environment and Property Management; Schnurle, P.; Liu, C.S. [National Taiwan Univ., Taipei, Taiwan (China). Inst. of Oceanography; Lee, C.S. [National Taiwan Ocean Univ., Keelung, Taiwan (China). Inst. of Applied Earth Science; Wang, Y.; Chung, S.H.; Chen, S.C. [Ministry of Economic Affairs, Taiwan (China). Central Geological Survey

    2008-07-01

    Regional multi-channel seismic reflection profiles that were conducted in Taiwan from 2003 to 2006 resulted in the identification of a gas hydrate-related bottom simulating reflector (BSR) in the broad southwestern offshore region of Taiwan. In order to understand the regional distribution of methane hydrate bearing layers and explore concentrated hydrate bearing layers, this paper presented a comprehensive analysis of reflection coefficient and amplitude-versus-offset (AVO) pattern of BSR using ocean bottom seismographs (OBSs) seismic data acquired in the southwestern offshore region of Taiwan. The study focused on the analysis and interpretation of airgun array signals recorded by OBSs during 2004 and 2006. Ten profiles of seismic reflection/refraction with a total length of about 140 km and recorded by 50 recovered OBSs were acquired on the active and passive margins in offshore southwestern Taiwan. Amplitudes of the direct water arrival, the multiple, and the BSR were picked interactively for all the OBS lines. A quantitative representation of reflector strength was provided by calculation of reflection coefficients. In general, the seafloor reflection coefficients for the active and passive margins were estimated as 0.1-0.25. The paper presented the data and analysis as well as the results of the study. It was concluded that the results of calculated reflection coefficient of the BSR in offshore southwest Taiwan suggested that inferred hydrate concentration for the passive margin profiles was relatively higher than that for the active margin profiles. 4 refs.

  17. Pattern formation in urbanism : A critical reflection on urban morphology, planning and design

    NARCIS (Netherlands)

    Çaliskan, O.

    2013-01-01

    This thesis is all about urban patterns, what we see through the windows of the plane with an admiration of their relief-like scenery covering the land surface. In a sense, the spatial pattern within our cities is the biggest collectively produced artifact of human beings. It is both the originator

  18. Variation pattern of particulate organic carbon and nitrogen in oceans and inland waters

    Science.gov (United States)

    Huang, Changchun; Jiang, Quanliang; Yao, Ling; Yang, Hao; Lin, Chen; Huang, Tao; Zhu, A.-Xing; Zhang, Yimin

    2018-03-01

    We examined the relationship between, and variations in, particulate organic carbon (POC) and particulate organic nitrogen (PON) based on previously acquired ocean and inland water data. The latitudinal dependency of POC / PON is significant between 20 and 90° N but weak in low-latitude areas and in the Southern Hemisphere. The mean values of POC / PON in the Southern Hemisphere and Northern Hemisphere were 7.40 ± 3.83 and 7.80 ± 3.92, respectively. High values of POC / PON appeared between 80-90 (12.2 ± 7.5) and 70-80° N (9.4 ± 6.4), while relatively low POC / PON was found from 20 (6.6 ± 2.8) to 40° N (6.7 ± 2.7). The latitudinal variation of POC / PON in the Northern Hemisphere is much stronger than in the Southern Hemisphere due to the influence of more terrestrial organic matter. Higher POC and PON could be expected in coastal waters. POC / PON growth ranged from 6.89 ± 2.38 to 7.59 ± 4.22 in the Northern Hemisphere, with an increasing rate of 0.0024 km from the coastal to open ocean. Variations of POC / PON in lake water also showed a similar latitude-variation tendency of POC / PON with ocean water but were significantly regulated by the lakes' morphology, trophic state and climate. Small lakes and high-latitude lakes prefer relatively high POC / PON, and large lakes and low-latitude lakes tend to prefer low POC / PON. The coupling relationship between POC and PON in oceans is much stronger than in inland waters. Variations in POC, PON and POC / PON in inland waters should receive more attention due to the implications of these values for the global carbon and nitrogen cycles and the indeterminacy of the relationship between POC and PON.

  19. Patterns of nitrogen export from a seasonal freezing agricultural watershed during the thawing period.

    Science.gov (United States)

    Zhao, Qiang; Chang, Dan; Wang, Kang; Huang, Jiesheng

    2017-12-01

    The objectives of this study were to investigate water, ammonium nitrogen (NH 4 + -N), and nitrate nitrogen (NO 3 - -N) export processes during the thawing period in a watershed with heavy agricultural activities and to evaluate contributions of N (i.e., NO 3 - -N and NH 4 + -N) from different source areas under different climate conditions. Experiments were conducted within the 75km 2 agricultural Heidingzi watershed in northeast China. The thawing period was divided into four stages: early-melt, late-melt, rain-on-melt, and post-melt. Drainage regions (DRs) were separated into three types. The processes of water and N discharge from soil into rivers were monitored in these DRs during the thawing periods of 2014, 2015, and 2016. Results show that the processes of water and N discharge were not synchronous during the thawing period. Variations in discharge concentrations of NH 4 + -N and NO 3 - -N during the thawing period were mainly affected by the flushing effect, which was controlled by the physical state of the surface water (snow or ice) and the melt rate of frozen soil. Contributions of N export from the DRs varied under different land uses and climate conditions during the thawing period. NO 3 - -N export was mainly from maize fields. Thawing stages with high NO 3 - -N export were always accompanied by higher discharge rates. NH 4 + -N export mainly occurred during the early-melt and late-melt stages and from riverside rural regions. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Investigation into the role of canopy structure traits and plant functional types in modulating the correlation between canopy nitrogen and reflectance in a temperate forest in northeast China

    Science.gov (United States)

    Yu, Quanzhou; Wang, Shaoqiang; Zhou, Lei

    2017-10-01

    A precise estimate of canopy leaf nitrogen concentration (CNC, based on dry mass) is important for researching the carbon assimilation capability of forest ecosystems. Hyperspectral remote sensing technology has been applied to estimate regional CNC, which can adjust forest photosynthetic capacity and carbon uptake. However, the relationship between forest CNC and canopy spectral reflectance as well as its mechanism is still poorly understood. Using measured CNC, canopy structure and species composition data, four vegetation indices (VIs), and near-infrared reflectance (NIR) derived from EO-1 Hyperion imagery, we investigated the role of canopy structure traits and plant functional types (PFTs) in modulating the correlation between CNC and canopy reflectance in a temperate forest in northeast China. A plot-scale forest structure indicator, named broad foliar dominance index (BFDI), was introduced to provide forest canopy structure and coniferous and broadleaf species composition. Then, we revealed the response of forest canopy reflectance spectrum to BFDI and CNC. Our results showed that leaf area index had no significant effect on NIR (P>0.05) but indicated that there was a significant correlation (R2=0.76, P0.05). On the contrary, removing the CNC effect, the partial correlation between BFDI and NIR was positively significant (R=0.69, Pforest types. Nevertheless, the relationship cannot be considered as a feasible approach of CNC estimation for a single PFT.

  1. State-dependent cellular activity patterns of the cat paraventricular hypothalamus measured by reflectance imaging

    DEFF Research Database (Denmark)

    Kristensen, Morten Pilgaard; Rector, D M; Poe, G R

    1996-01-01

    Activity within the cat paraventricular hypothalamus (PVH) during sleep and waking states was measured by quantifying intrinsic tissue reflectivity. A fiber optic probe consisting of a 1.0 mm coherent image conduit, surrounded by plastic fibers which conducted 660 nm source light, was attached...... to a charge-coupled device camera, and positioned over the PVH in five cats. Electrodes for assessing state variables, including electroencephalographic activity, eye movement, and somatic muscle tone were also placed. After surgical recovery, reflected light intensity was measured continuously at 2.5 Hz...

  2. Imaging the dorsal hippocampus: light reflectance relationships to electroencephalographic patterns during sleep

    DEFF Research Database (Denmark)

    Rector, D M; Poe, G R; Kristensen, Morten Pilgaard

    1995-01-01

    We assessed the correspondence of 660 nm light reflectance changes from the dorsal hippocampus with slow wave electroencephalographic (EEG) activity during quiet sleep (QS) and rapid eye movement (REM) sleep in four cats. An optic probe, attached to a charge-coupled-device (CCD) video camera...... as EEG changes. Dividing the image into 10 subregions revealed that reflectance changes at the rhythmical slow wave activity band (RSA, 4-6 Hz) persisted in localized regions during QS and REM sleep, but regional changes showed considerable wave-by-wave independence between areas and from slow wave...

  3. Plant species occurrence patterns in Eurasian grasslands reflect adaptation to nutrient ratios

    NARCIS (Netherlands)

    Roeling, Ineke S.; Ozinga, Wim A.; van Dijk, Jerry; Eppinga, Maarten B.; Wassen, Martin J.

    2018-01-01

    Previous studies of Eurasian grasslands have suggested that nutrient ratios, rather than absolute nutrient availabilities and associated productivity, may be driving plant species richness patterns. However, the underlying assumption that species occupy distinct niches along nutrient ratio gradients

  4. Biological nitrogen fixation: rates, patterns and ecological controls in terrestrial ecosystems

    Science.gov (United States)

    Vitousek, Peter M.; Menge, Duncan N.L.; Reed, Sasha C.; Cleveland, Cory C.

    2013-01-01

    New techniques have identified a wide range of organisms with the capacity to carry out biological nitrogen fixation (BNF)—greatly expanding our appreciation of the diversity and ubiquity of N fixers—but our understanding of the rates and controls of BNF at ecosystem and global scales has not advanced at the same pace. Nevertheless, determining rates and controls of BNF is crucial to placing anthropogenic changes to the N cycle in context, and to understanding, predicting and managing many aspects of global environmental change. Here, we estimate terrestrial BNF for a pre-industrial world by combining information on N fluxes with 15N relative abundance data for terrestrial ecosystems. Our estimate is that pre-industrial N fixation was 58 (range of 40–100) Tg N fixed yr−1; adding conservative assumptions for geological N reduces our best estimate to 44 Tg N yr−1. This approach yields substantially lower estimates than most recent calculations; it suggests that the magnitude of human alternation of the N cycle is substantially larger than has been assumed.

  5. Neural Activity Patterns in the Human Brain Reflect Tactile Stickiness Perception

    Science.gov (United States)

    Kim, Junsuk; Yeon, Jiwon; Ryu, Jaekyun; Park, Jang-Yeon; Chung, Soon-Cheol; Kim, Sung-Phil

    2017-01-01

    Our previous human fMRI study found brain activations correlated with tactile stickiness perception using the uni-variate general linear model (GLM) (Yeon et al., 2017). Here, we conducted an in-depth investigation on neural correlates of sticky sensations by employing a multivoxel pattern analysis (MVPA) on the same dataset. In particular, we statistically compared multi-variate neural activities in response to the three groups of sticky stimuli: A supra-threshold group including a set of sticky stimuli that evoked vivid sticky perception; an infra-threshold group including another set of sticky stimuli that barely evoked sticky perception; and a sham group including acrylic stimuli with no physically sticky property. Searchlight MVPAs were performed to search for local activity patterns carrying neural information of stickiness perception. Similar to the uni-variate GLM results, significant multi-variate neural activity patterns were identified in postcentral gyrus, subcortical (basal ganglia and thalamus), and insula areas (insula and adjacent areas). Moreover, MVPAs revealed that activity patterns in posterior parietal cortex discriminated the perceptual intensities of stickiness, which was not present in the uni-variate analysis. Next, we applied a principal component analysis (PCA) to the voxel response patterns within identified clusters so as to find low-dimensional neural representations of stickiness intensities. Follow-up clustering analyses clearly showed separate neural grouping configurations between the Supra- and Infra-threshold groups. Interestingly, this neural categorization was in line with the perceptual grouping pattern obtained from the psychophysical data. Our findings thus suggest that different stickiness intensities would elicit distinct neural activity patterns in the human brain and may provide a neural basis for the perception and categorization of tactile stickiness. PMID:28936171

  6. Initial shifts in nitrogen impact on ecosystem carbon fluxes in an alpine meadow: patterns and causes

    Science.gov (United States)

    Song, Bing; Sun, Jian; Zhou, Qingping; Zong, Ning; Li, Linghao; Niu, Shuli

    2017-09-01

    Increases in nitrogen (N) deposition can greatly stimulate ecosystem net carbon (C) sequestration through positive N-induced effects on plant productivity. However, how net ecosystem CO2 exchange (NEE) and its components respond to different N addition rates remains unclear. Using an N addition gradient experiment (six levels: 0, 2, 4, 8, 16, 32 gN m-2 yr-1) in an alpine meadow on the Qinghai-Tibetan Plateau, we explored the responses of different ecosystem C fluxes to an N addition gradient and revealed mechanisms underlying the dynamic responses. Results showed that NEE, ecosystem respiration (ER), and gross ecosystem production (GEP) all increased linearly with N addition rates in the first year of treatment but shifted to N saturation responses in the second year with the highest NEE (-7.77 ± 0.48 µmol m-2 s-1) occurring under an N addition rate of 8 gN m-2 yr-1. The saturation responses of NEE and GEP were caused by N-induced accumulation of standing litter, which limited light availability for plant growth under high N addition. The saturation response of ER was mainly due to an N-induced saturation response of aboveground plant respiration and decreasing soil microbial respiration along the N addition gradient, while decreases in soil microbial respiration under high N addition were caused by N-induced reductions in soil pH. We also found that various components of ER, including aboveground plant respiration, soil respiration, root respiration, and microbial respiration, responded differentially to the N addition gradient. These results reveal temporal dynamics of N impacts and the rapid shift in ecosystem C fluxes from N limitation to N saturation. Our findings bring evidence of short-term initial shifts in responses of ecosystem C fluxes to increases in N deposition, which should be considered when predicting long-term changes in ecosystem net C sequestration.

  7. State-dependent cellular activity patterns of the cat paraventricular hypothalamus measured by reflectance imaging

    DEFF Research Database (Denmark)

    Kristensen, Morten Pilgaard; Rector, D M; Poe, G R

    1996-01-01

    Activity within the cat paraventricular hypothalamus (PVH) during sleep and waking states was measured by quantifying intrinsic tissue reflectivity. A fiber optic probe consisting of a 1.0 mm coherent image conduit, surrounded by plastic fibers which conducted 660 nm source light, was attached...... to a charge-coupled device camera, and positioned over the PVH in five cats. Electrodes for assessing state variables, including electroencephalographic activity, eye movement, and somatic muscle tone were also placed. After surgical recovery, reflected light intensity was measured continuously at 2.5 Hz...... changes with behavioral state in a regionally specific manner, and that overall activity increases during quiet sleep, and is even more enhanced in active sleep. PVH activation could be expected to stimulate pituitary release of adrenocorticotropic hormone (ACTH) and affect input to autonomic regulatory...

  8. [Computer-assisted measurement of ocular misalignment in infants and young children using the digital Purkinje reflection pattern procedure].

    Science.gov (United States)

    Barry, J C; Effert, R; Kaupp, A; Kleine, M; Reim, M

    1994-02-01

    A digital image recording and processing system is presented that allows a quick diagnosis of microstrabismus in non-cooperative children. It is thus particularly suited for screening purposes. The Purkinje Reflection Pattern Evaluation (RPE) method is used: three small flashes are used to produce the desired Purkinje images. Two horizontal rows of the three 1st Purkinje images (anterior corneal reflections) and of the three 4th Purkinje images (posterior crystalline lens reflections) stemming from the three light sources form the characteristic Purkinje image reflection pattern. Each eye's position is calculated from the shift between the upper and lower rows of reflections by means of two simple formulae. From the angles obtained in binocular fixation and monocular fixation the manifest angle of strabismus corresponding to the angle measured in the simultaneous prism-and-cover test is computed. The measurement is performed at a fixation distance of 50 cm under natural viewing conditions. To obtain a picture one only has to get the child's attention for a short moment. The primary position is triggered with the fixation light, which is operated by a switch. The digital image recording is done with a hand-held device comprising two miniaturized video cameras, three photo flashes and a fixation light that is operated manually. An IBM-compatible PC equipped with a hard disk and two frame grabbers was adapted for the storage and processing of the pictures. The pictures are evaluated interactively in a few minutes on the workstation's monitor immediately after the measurement. To this end specially designed menu-driven software was implemented. Examples of the measuring procedure and clinical results in infants with microtropic highlight the potential of the system as a screening apparatus and for the exact measurement of small and large squint angles. Usually even 1-year-old children can cooperate well enough to get good-quality pictures in binocular fixation. The new

  9. Global Patterns of the Isotopic Composition of Soil and Plant Nitrogen

    Science.gov (United States)

    Amundson, R.; Yoo, K.

    2014-12-01

    From a societal perspective, soil N follows only soil C in the importance of soil to 21st century environmental issues. Amundson et al (2003) developed a mass balance model for soil N and the ratio of 15N/14N, and provided the first global projections of the spatial patterns of soil and plant δ15N values. It was hypothesized that state factors, particularly climate, should drive broad patterns of soil and plant δ15N values in a manner analogous to the known patterns of total soil N (e.g. Post et al., 1984). At that time, the N isotope data available to explore the effect of individual factors was modest. In the past decade, numerous papers from a broad spectrum of locations have created a rich database that can be used to further refine the initial projections made more than a decade ago. In this paper, hundreds of published measurements will be used to more deeply examine the climatic impacts on soil and plant δ15N values. Additionally, we will focus on the local controls of topography on ecosystem N cycling, which can create local isotopic variation that is similar in magnitude to the global effects of climate. The adoption of process-based models from the hillslope geomorphology community appears to be a powerful tool for explaining some existing data from toposequences, designing new studies of topographic controls on biogeochemistry, and particularly for parameterization in global models. Amundson, R., A.T. Austin, E.A.G. Schuur, K. Yoo, V. Matzek, C. Kendall, A. Uebersax, D. Brenner, and W.T. Baisden. 2003. Global Biogeochemical Cycles 17(1):1031.

  10. Global patterns and substrate-based mechanisms of the terrestrial nitrogen cycle

    DEFF Research Database (Denmark)

    Niu, Shuli; Classen, Aimee Taylor; Dukes, Jeffrey S.

    2016-01-01

    availability but increase exponentially and become the dominant fate of N at high loading rates. The original N saturation hypothesis emphasises sequential N saturation from plant uptake to soil retention before N losses occur. However, biogeochemical models that simulate simultaneous competition for soil N...... substrates by multiple processes match the observed patterns of N losses better than models based on sequential competition. To enable better prediction of terrestrial N cycle responses to N loading, we recommend that future research identifies the response functions of different N processes to substrate...

  11. Social Change, Competition and Inequality: Macro Societal Patterns Reflected in Curriculum Practices of Turkish Schools

    Science.gov (United States)

    Somel, Rahsan Nazli; Nohl, Arnd-Michael

    2015-01-01

    Curriculum reforms provide a unique opportunity to investigate how in times of social change education is not only influenced by, but also itself a driver of, competition and inequality. This article sheds light on a specific instance of how macro-societal patterns in education intermingle in twenty-first century Turkey by inquiring into a major…

  12. Understanding deviations in lithographic patterns near interfaces: Characterization of bottom anti-reflective coatings (BARC) and the BARC resist interface

    Science.gov (United States)

    Lenhart, Joseph L.; Fischer, Daniel; Sambasivan, Sharadha; Lin, Eric K.; Wu, Wen-Li; Guerrero, Douglas J.; Wang, Yubao; Puligadda, Rama

    2007-02-01

    Interactions between a bottom anti-reflective coating (BARC) and a photoresist can critically impact lithographic patterns. For example, a lithographic pattern can shrink or spread near a BARC interface, a process called undercutting or footing respectively, due to incompatibility between the two materials. Experiments were conducted on two industrial BARC coatings in an effort to determine the impact of BARC surface chemistry on the footing and undercutting phenomena. The BARC coatings were characterized by near edge X-ray absorption fine structure (NEXAFS), contact angle measurements, and neutron and X-ray reflectivity. Contact angle measurement using a variety of fluids showed that the fluid contact angles were independent of the type of BARC coating or the BARC processing temperature. NEXAFS measurements showed that the surface chemistry of each BARC was also independent of the processing temperature. These results suggest that acid-base interactions at the BARC-resist interface are not the cause of the footing-undercutting phenomena encountered in lithographic patterns.

  13. Initial shifts in nitrogen impact on ecosystem carbon fluxes in an alpine meadow: patterns and causes

    Directory of Open Access Journals (Sweden)

    B. Song

    2017-09-01

    Full Text Available Increases in nitrogen (N deposition can greatly stimulate ecosystem net carbon (C sequestration through positive N-induced effects on plant productivity. However, how net ecosystem CO2 exchange (NEE and its components respond to different N addition rates remains unclear. Using an N addition gradient experiment (six levels: 0, 2, 4, 8, 16, 32 gN m−2 yr−1 in an alpine meadow on the Qinghai–Tibetan Plateau, we explored the responses of different ecosystem C fluxes to an N addition gradient and revealed mechanisms underlying the dynamic responses. Results showed that NEE, ecosystem respiration (ER, and gross ecosystem production (GEP all increased linearly with N addition rates in the first year of treatment but shifted to N saturation responses in the second year with the highest NEE (−7.77 ± 0.48 µmol m−2 s−1 occurring under an N addition rate of 8 gN m−2 yr−1. The saturation responses of NEE and GEP were caused by N-induced accumulation of standing litter, which limited light availability for plant growth under high N addition. The saturation response of ER was mainly due to an N-induced saturation response of aboveground plant respiration and decreasing soil microbial respiration along the N addition gradient, while decreases in soil microbial respiration under high N addition were caused by N-induced reductions in soil pH. We also found that various components of ER, including aboveground plant respiration, soil respiration, root respiration, and microbial respiration, responded differentially to the N addition gradient. These results reveal temporal dynamics of N impacts and the rapid shift in ecosystem C fluxes from N limitation to N saturation. Our findings bring evidence of short-term initial shifts in responses of ecosystem C fluxes to increases in N deposition, which should be considered when predicting long-term changes in ecosystem net C sequestration.

  14. Statistical models for prediction of dry weight and nitrogen accumulation based on visible and near-infrared hyper-spectral reflectance of rice canopies

    International Nuclear Information System (INIS)

    Takahashi, W.; Nguyen-Cong, V.; Kawaguchi, S.; Minamiyama, M.; Ninomiya, S.

    2000-01-01

    Various multivariate regression models were examined with ten-fold cross-validation to develop efficient, accurate models to predict dry weight and nitrogen accumulation of rice crops (cultivars Koshihikari, Hanaechizen, Nipponbare, and IR-36) from the maximum tiller number stage to the meiosis stage, using plant-canopy reflectance of hyper-spectra within the 400-1100 nm domain without any variable selection. The results showed that the principal component regression using hyper-spectra gave better fits and predictability than that using specific wavelengths. On the other hand, partial least squares regression was the most useful among the models tested; this method avoided overfitting and multicollinearity by using all wavelength information without variable selection and by inclusion of both x and y variations in its latent variables. (author)

  15. Changes in transcript expression patterns as a result of cryoprotectant treatment and liquid nitrogen exposure in Arabidopsis shoot tips.

    Science.gov (United States)

    Gross, Briana L; Henk, Adam D; Bonnart, Remi; Volk, Gayle M

    2017-03-01

    Transcripts related to abiotic stress, oxidation, and wounding were differentially expressed in Arabidopsis shoot tips in response to cryoprotectant and liquid nitrogen treatment. Cryopreservation methods have been implemented in genebanks as a strategy to back-up plant genetic resource collections that are vegetatively propagated. Cryopreservation is frequently performed using vitrification methods, whereby shoot tips are treated with cryoprotectant solutions, such as Plant Vitrification Solution 2 (PVS2) or Plant Vitrification Solution 3 (PVS3); these solutions remove and/or replace freezable water within the meristem cells. We used the model system Arabidopsis thaliana to identify suites of transcripts that are up- or downregulated in response to PVS2 and PVS3 treatment and liquid nitrogen (LN) exposure. Our results suggest that there are many changes in transcript expression in shoot tips as a result of cryoprotection and that these changes exceed the number detected as a result of LN exposure. In total, 180 transcripts showed significant changes in expression level unique to treatment with either the cryoprotectant or cryopreservation followed by recovery. Of these 180 transcripts, 67 were related to stress, defense, wounding, lipid, carbohydrate, abscisic acid, oxidation, temperature (cold/heat), or osmoregulation. The responses of five transcripts were confirmed using qPCR methods. The transcripts responding to PVS2 + LN suggest an oxidative response to this treatment, whereas the PVS3 + LN treatment invoked a more general metabolic response. This work shows that the choice of cryoprotectant can have a major influence on the patterns of transcript expression, presumably due to the level and extent of stress experienced by the shoot tip. As a result, there may be divergent responses of study systems to PVS2 and PVS3 treatments.

  16. Multi-segmental movement patterns reflect juggling complexity and skill level.

    Science.gov (United States)

    Zago, Matteo; Pacifici, Ilaria; Lovecchio, Nicola; Galli, Manuela; Federolf, Peter Andreas; Sforza, Chiarella

    2017-08-01

    The juggling action of six experts and six intermediates jugglers was recorded with a motion capture system and decomposed into its fundamental components through Principal Component Analysis. The aim was to quantify trends in movement dimensionality, multi-segmental patterns and rhythmicity as a function of proficiency level and task complexity. Dimensionality was quantified in terms of Residual Variance, while the Relative Amplitude was introduced to account for individual differences in movement components. We observed that: experience-related modifications in multi-segmental actions exist, such as the progressive reduction of error-correction movements, especially in complex task condition. The systematic identification of motor patterns sensitive to the acquisition of specific experience could accelerate the learning process. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Fabrication of high-resolution reflective scale grating for an optical encoder using a patterned self-assembly process

    International Nuclear Information System (INIS)

    Fan, Shanjin; Jiang, Weitao; Li, Xuan; Yu, Haoyu; Lei, Biao; Shi, Yongsheng; Yin, Lei; Chen, Bangdao; Liu, Hongzhong

    2016-01-01

    Steel tape scale grating of a reflective incremental linear encoder has a key impact on the measurement accuracy of the optical encoder. However, it is difficult for conventional manufacturing processes to fabricate scale grating with high-resolution grating strips, due to process and material problems. In this paper, self-assembly technology was employed to fabricate high-resolution steel tape scale grating for a reflective incremental linear encoder. Graphene oxide nanoparticles were adopted to form anti-reflective grating strips of steel tape scale grating. They were deposited in the tape, which had a hydrophobic and hydrophilic grating pattern when the dispersion of the nanoparticles evaporated. A standard lift-off process was employed to fabricate the hydrophobic grating strips on the steel tape. Simultaneously, the steel tape itself presents a hydrophilic property. The hydrophobic and hydrophilic grating pattern was thus obtained. In this study, octafluorocyclobutane was used to prepare the hydrophobic grating strips, due to its hydrophobic property. High-resolution graphene oxide steel tape scale grating with a pitch of 20 μ m was obtained through the self-assembly process. The photoelectric signals of the optical encoder containing the graphene oxide scale grating and conventional scale grating were tested under the same conditions. Comparison test results showed that the graphene oxide scale grating has a better performance in its amplitude and harmonic components than that of the conventional steel tape scale. A comparison experiment of position errors was also conducted, demonstrating an improvement in the positioning error of the graphene oxide scale grating. The comparison results demonstrated the applicability of the proposed self-assembly process to fabricate high-resolution graphene oxide scale grating for a reflective incremental linear encoder. (paper)

  18. Phenotypic Plasticity Explains Response Patterns of European Beech (Fagus sylvatica L. Saplings to Nitrogen Fertilization and Drought Events

    Directory of Open Access Journals (Sweden)

    Christoph Dziedek

    2017-03-01

    Full Text Available Abstract: Climate and atmospheric changes affect forest ecosystems worldwide, but little is known about the interactive effects of global change drivers on tree growth. In the present study, we analyzed single and combined effects of nitrogen (N fertilization and drought events (D on the growth of European beech (Fagus sylvatica L. saplings in a greenhouse experiment. We quantified morphological and physiological responses to treatments for one‐ and two‐year‐old plants. N fertilization increased the saplings’ aboveground biomass investments, making them more susceptible to D treatments. This was reflected by the highest tissue dieback in combined N and D treatments and a significant N × D interaction for leaf δ13C signatures. Thus, atmospheric N deposition can strengthen the drought sensitivity of beech saplings. One‐year‐old plants reacted more sensitively to D treatments than two‐year‐old plants (indicated by D‐induced shifts in leaf δ13C signatures of one‐year‐old and two‐year‐old plants by +0.5‰ and −0.2‰, respectively, attributable to their higher shoot:root‐ratios (1.8 and 1.2, respectively. In summary, the saplings’ treatment responses were determined by their phenotypic plasticity (shifts in shoot:root‐ratios, which in turn was a function of both the saplings’ age (effects of allometric growth trajectories = apparent plasticity and environmental impacts (effects of N fertilization = plastic allometry.

  19. Growth and Pattern of Women’s Studies in Malaysia as Reflected by Generated Literature

    OpenAIRE

    Zainab, A.N.

    2008-01-01

    The study uses research-based resources listed in two published bibliographies on “Women in development in Malaysia” produced between the pre 1970 years and 2004 to describe the growth and pattern of women’s studies in Malaysia. A total 4037 resources formed the basis of the study. Bibliometric measure are used to indicate the annual growth of literature over the periods, the preferred publication channels used by the authors, the subject areas of research interests, the active authors and th...

  20. Resting-state brain activity in the motor cortex reflects task-induced activity: A multi-voxel pattern analysis.

    Science.gov (United States)

    Kusano, Toshiki; Kurashige, Hiroki; Nambu, Isao; Moriguchi, Yoshiya; Hanakawa, Takashi; Wada, Yasuhiro; Osu, Rieko

    2015-08-01

    It has been suggested that resting-state brain activity reflects task-induced brain activity patterns. In this study, we examined whether neural representations of specific movements can be observed in the resting-state brain activity patterns of motor areas. First, we defined two regions of interest (ROIs) to examine brain activity associated with two different behavioral tasks. Using multi-voxel pattern analysis with regularized logistic regression, we designed a decoder to detect voxel-level neural representations corresponding to the tasks in each ROI. Next, we applied the decoder to resting-state brain activity. We found that the decoder discriminated resting-state neural activity with accuracy comparable to that associated with task-induced neural activity. The distribution of learned weighted parameters for each ROI was similar for resting-state and task-induced activities. Large weighted parameters were mainly located on conjunctive areas. Moreover, the accuracy of detection was higher than that for a decoder whose weights were randomly shuffled, indicating that the resting-state brain activity includes multi-voxel patterns similar to the neural representation for the tasks. Therefore, these results suggest that the neural representation of resting-state brain activity is more finely organized and more complex than conventionally considered.

  1. Surface segregation of InGaAs films by the evolution of reflection high-energy electron diffraction patterns

    International Nuclear Information System (INIS)

    Zhou Xun; Luo Zi-Jiang; Guo Xiang; Zhang Bi-Chan; Shang Lin-Tao; Zhou Qing; Deng Chao-Yong; Ding Zhao

    2012-01-01

    Surface segregation is studied via the evolution of reflection high-energy electron diffraction (RHEED) patterns under different values of As 4 BEP for InGaAs films. When the As 4 BEP is set to be zero, the RHEED pattern keeps a 4×3/(n × 3) structure with increasing temperature, and surface segregation takes place until 470 °C. The RHEED pattern develops into a metal-rich (4 × 2) structure as temperature increases to 495 °C. The reason for this is that surface segregation makes the In inside the InGaAs film climb to its surface. With the temperature increasing up to 515 °C, the RHEED pattern turns into a GaAs(2 × 4) structure due to In desorption. While the As 4 BEP comes up to a specific value (1.33 × 10 -4 Pa−1.33 × 10 -3 Pa), the surface temperature can delay the segregation and desorption. We find that As 4 BEP has a big influence on surface desorption, while surface segregation is more strongly dependent on temperature than surface desorption. (condensed matter: structural, mechanical, and thermal properties)

  2. Fifteen-year patterns of soil carbon and nitrogen following biomass harvesting

    Science.gov (United States)

    Kurth, Valerie J.; D'Amato, Anthony W.; Palik, Brian J.; Bradford, John B.

    2014-01-01

    The substitution of forest-derived woody biofuels for fossil fuel energy has garnered increasing attention in recent years, but information regarding the mid- and long-term effects on soil productivity is limited. We investigated 15-yr temporal trends in forest floor and mineral soil (0–30 cm) C and N pools in response to organic matter removal treatments (OMR; stem-only harvest, SOH; whole-tree harvest, WTH; and whole-tree plus forest floor removal, FFR) at three edaphically distinct aspen (Populus tremuloides Michx. and P. grandidentata Michx.) forests in the Great Lakes region. The OMR and temporal effects were generally site specific, and both were most evident in the forest floor and combined profile (mineral soil and forest floor) compared with the mineral soil alone. Forest floor and combined profile C and N pools were generally similar in the SOH and WTH treatments, suggesting that slash retention has little impact on soil C and N in this time frame. Temporal changes in C and N at one of the three sites were consistent with patterns documented following exotic earthworm invasion, but mineral soil pools at the other two sites were stable over time. Power analyses demonstrated that significant effects were more likely to be detected for temporal differences than the effects of OMR and in the combined profile than in the mineral soil. Our findings are consistent with previous work demonstrating that OMR effects on soil C and N pools are site specific and more apparent in the forest floor than the mineral soil.

  3. Precedents, Patterns and Puzzles: Feminist Reflections on the First Women Lawyers

    Directory of Open Access Journals (Sweden)

    Mary Jane Mossman

    2016-10-01

    Full Text Available This paper initially examines the historical precedents established by some of the first women who entered the “gentleman’s profession” of law in different jurisdictions, as well as the biographical patterns that shaped some women’s ambitions to enter the legal professions. The paper then uses feminist methods and theories to interpret “puzzles that remain unsolved” about early women lawyers, focusing especially on two issues. One puzzle is the repeated claims on the part of many of these early women lawyers that they were “lawyers”, and not “women lawyers”, even as they experienced exclusionary practices and discrimination on the part of male lawyers and judges—a puzzle that suggests how professional culture required women lawyers to conform to existing patterns in order to succeed. A second puzzle relates to the public voices of early women lawyers, which tended to suppress disappointments, difficulties and discriminatory practices. In this context, feminist theories suggest a need to be attentive to the “silences” in women’s stories, including the stories of the lives of early women lawyers. Moreover, these insights may have continuing relevance for contemporary women lawyers because it is at least arguable that, while there have been changes in women’s experiences, there has been very little transformation in their work status in relation to men.

  4. Trabecular architecture of the manual elements reflects locomotor patterns in primates.

    Science.gov (United States)

    Matarazzo, Stacey A

    2015-01-01

    The morphology of trabecular bone has proven sensitive to loading patterns in the long bones and metacarpal heads of primates. It is expected that we should also see differences in the manual digits of primates that practice different methods of locomotion. Primate proximal and middle phalanges are load-bearing elements that are held in different postures and experience different mechanical strains during suspension, quadrupedalism, and knuckle walking. Micro CT scans of the middle phalanx, proximal phalanx and the metacarpal head of the third ray were used to examine the pattern of trabecular orientation in Pan, Gorilla, Pongo, Hylobates and Macaca. Several zones, i.e., the proximal ends of both phalanges and the metacarpal heads, were capable of distinguishing between knuckle-walking, quadrupedal, and suspensory primates. Orientation and shape seem to be the primary distinguishing factors but differences in bone volume, isotropy index, and degree of anisotropy were seen across included taxa. Suspensory primates show primarily proximodistal alignment in all zones, and quadrupeds more palmar-dorsal orientation in several zones. Knuckle walkers are characterized by having proximodistal alignment in the proximal ends of the phalanges and a palmar-dorsal alignment in the distal ends and metacarpal heads. These structural differences may be used to infer locmotor propensities of extinct primate taxa.

  5. Blue-green fluorescence and visible-infrared reflectance of corn (Zea mays L.) grain for in situ field detection of nitrogen supply

    International Nuclear Information System (INIS)

    McMurtrey, J.E. III; Chappelle, E.W.; Kim, M.S.; Corp, L.A.; Daughtry, C.S.T.

    1996-01-01

    The sensing of spectral attributes of corn (Zea mays L.) grain from site specific areas of the field during the harvest process may be useful in managing agronomic inputs and production practices on those areas of the field in subsequent growing seasons. Eight levels of nitrogen (N) fertilization were applied to field grown corn at Beltsville, Maryland. These N treatments produced a range of chlorophyll levels, biomass and physiological condition in the live plant canopies. After harvest, spectra were obtained in the laboratory on whole grain samples. Fluorescence emissions were acquired from 400 to 600 nm and percent reflectance were measured in the visible (VIS) near infrared (NIR) and mid-infrared (MIR) regions from 400 nm to 2400 nm. A ultraviolet (UV) excitation band centered at 385 nm was the most effective in producing fluorescence emission differences in the blue-green region of the fluorescence spectrum with maxima centered from 430-470nm in the blue and with an intense shoulder centered at around 530-560 nm in the green region. Reflectance showed the most spectral differences in the NIR and MIR (970-2330 nm) regions

  6. Patterns in stable isotope values of nitrogen and carbon in particulate matter from the Northwest Atlantic Continental Shelf, from the Gulf of Maine to Cape Hatteras

    Directory of Open Access Journals (Sweden)

    Autumn Oczkowski

    2016-12-01

    Full Text Available Stable isotope measurements of nitrogen and carbon (δ15N, δ13C are often used to characterize estuarine, nearshore, and open ocean ecosystems. Reliable information about the spatial distribution of base-level stable isotope values, often represented by primary producers, is critical to interpreting values in these ecosystems. While base-level isotope data are generally readily available for estuaries, nearshore coastal waters, and the open ocean, the continental shelf is less studied. To address this, and as a first step towards developing a surrogate for base-level isotopic signature in this region, we collected surface and deep water samples from the United States’ eastern continental shelf in the Western Atlantic Ocean, from the Gulf of Maine to Cape Hatteras, periodically between 2000 and 2013. During the study, particulate matter δ15N values ranged from 0.8 to 17.4 ‰, and δ13C values from -26.4 to -15.6 ‰ over the region. We used spatial autocorrelation analysis and random forest modeling to examine the spatial trends and potential environmental drivers of the stable isotope values. We observed general trends towards lower values for both nitrogen and carbon isotopes at the seaward edge of the shelf. Conversely, higher δ15N and δ13C values were observed on the landward edge of the shelf, in particular in the southern portion of the sampling area. Across all sites, the magnitude of the difference between the δ15N of subsurface and surface particulate matter (PM significantly increased with water depth (r2 = 0.41, df = 35, p < 0.001, while δ13C values did not change. There were significant positive correlation between δ15N and δ13C values for surface PM in each of the three marine ecoregions that make up the study area. Stable isotope dynamics on the shelf can inform both nearshore and open ocean research efforts, reflecting regional productivity patterns and, even possibly, large-scale climate fluctuations.

  7. Use of genotype-environment interactions to elucidate the pattern of maize root plasticity to nitrogen deficiency.

    Science.gov (United States)

    Li, Pengcheng; Zhuang, Zhongjuan; Cai, Hongguang; Cheng, Shuai; Soomro, Ayaz Ali; Liu, Zhigang; Gu, Riliang; Mi, Guohua; Yuan, Lixing; Chen, Fanjun

    2016-03-01

    Maize (Zea mays L.) root morphology exhibits a high degree of phenotypic plasticity to nitrogen (N) deficiency, but the underlying genetic architecture remains to be investigated. Using an advanced BC4 F3 population, we investigated the root growth plasticity under two contrasted N levels and identified the quantitative trait loci (QTLs) with QTL-environment (Q × E) interaction effects. Principal components analysis (PCA) on changes of root traits to N deficiency (ΔLN-HN) showed that root length and biomass contributed for 45.8% in the same magnitude and direction on the first PC, while root traits scattered highly on PC2 and PC3. Hierarchical cluster analysis on traits for ΔLN-HN further assigned the BC4 F3 lines into six groups, in which the special phenotypic responses to N deficiency was presented. These results revealed the complicated root plasticity of maize in response to N deficiency that can be caused by genotype-environment (G × E) interactions. Furthermore, QTL mapping using a multi-environment analysis identified 35 QTLs for root traits. Nine of these QTLs exhibited significant Q × E interaction effects. Taken together, our findings contribute to understanding the phenotypic and genotypic pattern of root plasticity to N deficiency, which will be useful for developing maize tolerance cultivars to N deficiency. © 2015 Institute of Botany, Chinese Academy of Sciences.

  8. Lévy flight and Brownian search patterns of a free-ranging predator reflect different prey field characteristics.

    Science.gov (United States)

    Sims, David W; Humphries, Nicolas E; Bradford, Russell W; Bruce, Barry D

    2012-03-01

    1. Search processes play an important role in physical, chemical and biological systems. In animal foraging, the search strategy predators should use to search optimally for prey is an enduring question. Some models demonstrate that when prey is sparsely distributed, an optimal search pattern is a specialised random walk known as a Lévy flight, whereas when prey is abundant, simple Brownian motion is sufficiently efficient. These predictions form part of what has been termed the Lévy flight foraging hypothesis (LFF) which states that as Lévy flights optimise random searches, movements approximated by optimal Lévy flights may have naturally evolved in organisms to enhance encounters with targets (e.g. prey) when knowledge of their locations is incomplete. 2. Whether free-ranging predators exhibit the movement patterns predicted in the LFF hypothesis in response to known prey types and distributions, however, has not been determined. We tested this using vertical and horizontal movement data from electronic tagging of an apex predator, the great white shark Carcharodon carcharias, across widely differing habitats reflecting different prey types. 3. Individual white sharks exhibited movement patterns that predicted well the prey types expected under the LFF hypothesis. Shark movements were best approximated by Brownian motion when hunting near abundant, predictable sources of prey (e.g. seal colonies, fish aggregations), whereas movements approximating truncated Lévy flights were present when searching for sparsely distributed or potentially difficult-to-detect prey in oceanic or shelf environments, respectively. 4. That movement patterns approximated by truncated Lévy flights and Brownian behaviour were present in the predicted prey fields indicates search strategies adopted by white sharks appear to be the most efficient ones for encountering prey in the habitats where such patterns are observed. This suggests that C. carcharias appears capable of exhibiting

  9. Suitable flow pattern increases the removal efficiency of nitrogen in gravity sewers: a suitable anoxic and aerobic environment in biofilms.

    Science.gov (United States)

    He, Qiang; Yin, Feixian; Li, Hong; Wang, Yinliang; Xu, Jingwei; Ai, Hainan

    2018-03-25

    The sewers have the function of carbon removal, which has been proven. But if the effect of nitrogen removal can be enhanced at the same time of carbon removal, it can lay a foundation for the realization of "sewer's working as a reactor." This paper investigated the effects of shear stress and C/N ratio on nitrogen removal through biofilms on the sewer inner wall and nitrogen transfer. The main conclusions are as follows: (1) nitrogen could be partially removed in sewers after a series of reactions; (2) the anaerobic, anoxic, aerobic environment and some bacteria related to nitrogen metabolism, which exist in the biofilm, promote the nitrification and denitrification; (3) a total of 722 functional genes involved in nitrogen metabolism were detected in the biofilm (C/N ratio of 10, shear stress of 1.4 Pa), accounting for 0.67% of all genes, and the functional genes related to denitrification were dominant. Graphical abstract ᅟ.

  10. Novel anti-reflection technology for GaAs single-junction solar cells using surface patterning and Au nanoparticles.

    Science.gov (United States)

    Kim, Youngjo; Lam, Nguyen Dinh; Kim, Kangho; Kim, Sangin; Rotermund, Fabian; Lim, Hanjo; Lee, Jaejin

    2012-07-01

    Single-junction GaAs solar cell structures were grown by low-pressure MOCVD on GaAs (100) substrates. Micro-rod arrays with diameters of 2 microm, 5 microm, and 10 microm were fabricated on the surfaces of the GaAs solar cells via photolithography and wet chemical etching. The patterned surfaces were coated with Au nanoparticles using an Au colloidal solution. Characteristics of the GaAs solar cells with and without the micro-rod arrays and Au nanoparticles were investigated. The short-circuit current density of the GaAs solar cell with 2 microm rod arrays and Au nanoparticles increased up to 34.9% compared to that of the reference cell without micro-rod arrays and Au nanoparticles. The conversion efficiency of the GaAs solar cell that was coated with Au nanoparticles on the patterned surface with micro-rod arrays can be improved from 14.1% to 19.9% under 1 sun AM 1.5G illumination. These results show that micro-rod arrays and Au nanoparticle coating can be applied together in surface patterning to achieve a novel cost-effective anti-reflection technology.

  11. Foliar Nutrient Distribution Patterns in Sympatric Maple Species Reflect Contrasting Sensitivity to Excess Manganese.

    Science.gov (United States)

    Fernando, Denise R; Marshall, Alan T; Lynch, Jonathan P

    2016-01-01

    Sugar maple and red maple are closely-related co-occurring tree species significant to the North American forest biome. Plant abiotic stress effects including nutritional imbalance and manganese (Mn) toxicity are well documented within this system, and are implicated in enhanced susceptibility to biotic stresses such as insect attack. Both tree species are known to overaccumulate foliar manganese (Mn) when growing on unbuffered acidified soils, however, sugar maple is Mn-sensitive, while red maple is not. Currently there is no knowledge about the cellular sequestration of Mn and other nutrients in these two species. Here, electron-probe x-ray microanalysis was employed to examine cellular and sub-cellular deposition of excessively accumulated foliar Mn and other mineral nutrients in vivo. For both species, excess foliar Mn was deposited in symplastic cellular compartments. There were striking between-species differences in Mn, magnesium (Mg), sulphur (S) and calcium (Ca) distribution patterns. Unusually, Mn was highly co-localised with Mg in mesophyll cells of red maple only. The known sensitivity of sugar maple to excess Mn is likely linked to Mg deficiency in the leaf mesophyll. There was strong evidence that Mn toxicity in sugar maple is primarily a symplastic process. For each species, leaf-surface damage due to biotic stress including insect herbivory was compared between sites with acidified and non-acidified soils. Although it was greatest overall in red maple, there was no difference in biotic stress damage to red maple leaves between acidified and non-acidified soils. Sugar maple trees on buffered non-acidified soil were less damaged by biotic stress compared to those on unbuffered acidified soil, where they are also affected by Mn toxicity abiotic stress. This study concluded that foliar nutrient distribution in symplastic compartments is a determinant of Mn sensitivity, and that Mn stress hinders plant resistance to biotic stress.

  12. Nitrogen-rich higher-molecular soil organic compounds patterned by lignin degradation products: Considerations on the nature of soil organic nitrogen

    Science.gov (United States)

    Liebner, Falk; Bertoli, Luca; Pour, Georg; Klinger, Karl; Ragab, Tamer; Rosenau, Thomas

    2016-04-01

    The pathways leading to accumulation of covalently bonded nitrogen in higher-molecular soil organic matter (SOM) are still a controversial issue in soil science and geochemistry. Similarly, structural elucidation of the variety of the types of nitrogenous moieties present in SOM is still in its infancy even though recent NMR studies suggest amide-type nitrogen to form the majority of organically bonded nitrogen which is, however, frequently not in accordance with the results of wet-chemical analyses. Following the modified polyphenol theory of Flaig and Kononova but fully aware of the imperfection of a semi-abiotic simulation approach, this work communicates the results of a study that investigated some potential nitrogen accumulation pathways occurring in the re-condensation branch of the theory following the reactions between well-known low-molecular lignin and carbohydrate degradation products with nitrogenous nucleophiles occurring in soils under aerobic conditions. Different low-molecular degradation products of lignin, cellulose, and hemicellulose, such as hydroquinone, methoxyhydroquinone, p-benzoquinone, 2,5-dihydroxy-[1,4]benzoquinone, glucose, xylose, and the respective polysaccharides, i.e. cellulose, xylan as well as various types of lignin were subjected to a joint treatment with oxygen and low-molecular N-nucleophiles, such as ammonia, amines, and amino acids in aqueous conditions, partly using respective 15N labeled compounds for further 15N CPMAS NMR studies. Product mixtures derived from mono- and polysaccharides have been comprehensively fractionated and analyzed by GC/MS after derivatization. Some of ammoxidized polyphenols and quinones have been analyzed by X-ray photoelectron spectroscopy. Some products, such as those obtained from ammoxidation of methoxy hydroquinone using 15N labeled ammonia were fractionated following the IHSS protocol. Individual humin (H), humic acid (HA), and fulvic acid (FA) fractions were subjected to elemental analyses

  13. Storage, patterns, and control of soil organic carbon and nitrogen in the northeastern margin of the Qinghai–Tibetan Plateau

    International Nuclear Information System (INIS)

    Liu Wenjie; Chen Shengyun; Qin Xiang; Zhou Zhaoye; Sun Weijun; Ren Jiawen; Qin Dahe; Baumann, Frank; Scholten, Thomas; Zhang Tongzuo

    2012-01-01

    This study tested the hypothesis that soil organic carbon (SOC) and total nitrogen (TN) spatial distributions show clear relationships with soil properties and vegetation composition as well as climatic conditions. Further, this study aimed to find the corresponding controlling parameters of SOC and TN storage in high-altitude ecosystems. The study was based on soil, vegetation and climate data from 42 soil pits taken from 14 plots. The plots were investigated during the summers of 2009 and 2010 at the northeastern margin of the Qinghai–Tibetan Plateau. Relationships of SOC density with soil moisture, soil texture, biomass and climatic variables were analyzed. Further, storage and vertical patterns of SOC and TN of seven representative vegetation types were estimated. The results show that significant relationships of SOC density with belowground biomass (BGB) and soil moisture (SM) can be observed. BGB and SM may be the dominant factors influencing SOC density in the topsoil of the study area. The average densities of SOC and TN at a depth of 1 m were about 7.72 kg C m −2 and 0.93 kg N m −2 . Both SOC and TN densities were concentrated in the topsoil (0–20 cm) and fell exponentially as soil depth increased. Additionally, the four typical vegetation types located in the northwest of the study area were selected to examine the relationship between SOC and environmental factors (temperature and precipitation). The results indicate that SOC density has a negative relationship with temperature and a positive relationship with precipitation diminishing with soil depth. It was concluded that SOC was concentrated in the topsoil, and that SOC density correlates well with BGB. SOC was predominantly influenced by SM, and to a much lower extent by temperature and precipitation. This study provided a new insight in understanding the control of SOC and TN density in the northeastern margin of the Qinghai–Tibetan Plateau. (letter)

  14. Stable nitrogen isotope analysis of dentine serial sections elucidate sex differences in weaning patterns of wild chimpanzees (Pan troglodytes).

    Science.gov (United States)

    Fahy, Geraldine E; Richards, Michael P; Fuller, Benjamin T; Deschner, Tobias; Hublin, Jean-Jacques; Boesch, Christophe

    2014-04-01

    Offspring provisioning is one of the most energetically demanding aspects of reproduction for female mammals. Variation in lactation length and weaning strategies between chimpanzees (Pan troglodytes), our closest living relative, and modern human societies have been reported. When and why these changes occurred is frequently debated. Our study used stable nitrogen isotope data of tooth root dentine from wild Western chimpanzees (Pan troglodytes verus) in Taï National Park, Côte d'Ivoire, to quantify weaning in these chimpanzees and explore if infant sex plays a role in maternal investment. We analyzed serial sections of deciduous lateral incisor root dentine from four Taï chimpanzees to establish the δ(15) N signal of nursing infants; we then analyzed serial sections of first permanent mandibular molar root dentine from 12 Taï chimpanzees to provide quantitative δ(15) N data on weaning in this population. Up to 2 years of age both sexes exhibited dentine δ(15) N values ≈2-3‰ higher than adult female Taï chimpanzees, consistent with a nursing signal. Thereafter a steady decrease in δ(15) N values consistent with the onset, and progression, of weaning, was visible. Sex differences were also evident, where male δ(15) N values decreased at a significantly slower rate compared to females. Confirmation of sex differences in maternal investment among Taï chimpanzees, demonstrates the viability of using isotope analysis to investigate weaning in non-human primates. Additionally, assuming that behaviors observed in the Taï chimpanzees are illustrative of the ancestral pattern, our results provide a platform to enable the trajectory of weaning in human evolution to be further explored. Copyright © 2013 Wiley Periodicals, Inc.

  15. Effects of nitrogen application rate and leaf age on the distribution pattern of leaf SPAD readings in the rice canopy.

    Directory of Open Access Journals (Sweden)

    Hu Yang

    Full Text Available A Soil-Plant Analysis Development (SPAD chlorophyll meter can be used as a simple tool for evaluating N concentration of the leaf and investigating the combined effects of nitrogen rate and leaf age on N distribution. We conducted experiments in a paddy field over two consecutive years (2008-2009 using rice plants treated with six different N application levels. N distribution pattern was determined by SPAD readings based on the temporal dynamics of N concentrations in individual leaves. At 62 days after transplantation (DAT in 2008 and DAT 60 in 2009, leaf SPAD readings increased from the upper to lower in the rice canopy that received N levels of 150 to 375 kg ha(-1The differences in SPAD readings between the upper and lower leaf were larger under higher N application rates. However, as plants grew, this atypical distribution of SPAD readings in canopy leaf quickly reversed to the general order. In addition, temporal dynamics of the leaf SPAD readings (N concentrations were fitted to a piecewise function. In our model, changes in leaf SPAD readings were divided into three stages: growth, functioning, and senescence periods. The leaf growth period lasted approximately 6 days, and cumulative growing days were not affected by N application rates. The leaf functioning period was represented with a relatively stable SPAD reading related to N application rate, and cumulative growing days were extended with increasing N application rates. A quadratic equation was utilized to describe the relationship between SPAD readings and leaf age during the leaf senescence period. The rate of decrease in SPAD readings increased with the age of leaves, but the rate was slowed by N application. As leaves in the lower canopy were physiologically older than leaves in the upper canopy, the rate of decrease in SPAD readings was faster in the lower leaves.

  16. Rice agriculture impacts catchment hydrographic patterns and nitrogen export characteristics in subtropical central China: a paired-catchment study.

    Science.gov (United States)

    Wang, Yi; Liu, Xinliang; Wang, Hua; Li, Yong; Li, Yuyuan; Liu, Feng; Xiao, Runlin; Shen, Jianlin; Wu, Jinshui

    2017-06-01

    Increased nitrogen (N) concentrations in water bodies have highlighted issues regarding nutrient pollution in agricultural catchments. In this study, the ammonium-N (NH 4 + -N), nitrate-N (NO 3 - -N), and total N (TN) concentrations were observed in the stream water and groundwater of two contrasting catchments (named Tuojia and Jianshan) in subtropical central China from 2010 to 2014, to determine the rice agriculture impacts on the hydrographic patterns, and N export characteristics of the catchments. The results suggested that greater amounts of stream flow (523.0 vs. 434.7 mm year -1 ) and base flow (237.6 vs. 142.8 mm year -1 ) were produced in Tuojia than in Jianshan, and a greater base flow contribution to stream flow and higher frequencies of high-base flow days were observed during the fallow season than during the rice-growing season, indicating that intensive rice agriculture strongly influences the catchment hydrographic pattern. Rice agriculture resulted in moderate N pollution in the stream water and groundwater, particularly in Tuojia. Primarily, rice agriculture increased the NH 4 + -N concentration in the stream water; however, it increased the NO 3 - -N concentrations in the groundwater, suggesting that the different N species in the paddy fields migrated out of the catchments through distinct hydrological pathways. The average TN loading via stream flow and base flow was greater in Tuojia than in Jianshan (1.72 and 0.58 vs. 0.72 and 0.15 kg N ha -1  month -1 , respectively). Greater TN loading via stream flow was observed during the fallow season in Tuojia and during the rice-growing season in Jianshan, and these different results were most likely a result of the higher base flow contribution to TN loading (33.5 vs. 21.3%) and greater base flow enrichment ratio (1.062 vs. 0.876) in Tuojia than in Jianshan. Therefore, the impact of rice agriculture on catchment eco-hydrological processes should be considered when performing water quality

  17. Prediction of purine derivatives, creatinine and total nitrogen concentrations in urine by FT-Near-lnfrared Reflectance spectroscopy (FT-NIR)

    International Nuclear Information System (INIS)

    Susmel, P.; Piani, B.; Toso, B.; Stefanon, B.

    2004-01-01

    The objective of this study was to provide an alternative method for the determination of purine derivatives (PD, which include allantoin, uric acid, hypoxanthine and xanthine), creatinine and total nitrogen (N) concentrations in urine. About 180 urine samples from cattle, buffaloes and rabbit were collected and analyzed for PD by HPLC, creatinine by spectrophotometry and N by Kjeldahl method. The urine samples were then analyzed by Fourier Transformed Near Infrared Reflectance Spectroscopy (FT-NIR) to find conformity between this technique and the HPLC and colorimetric methods. FT-NIR can predict allantoin, uric acid, hypoxanthine, xanthine, creatinine, total N and sum of N in both allantoin and uric acid with a satisfactory level of accuracy: the determination coefficient (r 2 ) of validation ranged from 0.888% for uric acid to 0.982% for total N. The coefficients of determination for allantoin, creatinine and sum of N in both allantoin and uric acid were 0.92, 0.894 and 0.90%, respectively. Hypoxanthine and xanthine in urine samples were not detectable by NIRS, probably because of their low concentrations, and therefore they were not considered for instrumental calibration. (author)

  18. Mucin pattern reflects the origin of the adenocarcinoma in Barrett's esophagus: a retrospective clinical and laboratorial study

    Directory of Open Access Journals (Sweden)

    Corbett Carlos

    2009-03-01

    Full Text Available Abstract Background Mucin immunoexpression in adenocarcinoma arising in Barrett's esophagus (BE may indicate the carcinogenesis pathway. The aim of this study was to evaluate resected specimens of adenocarcinoma in BE for the pattern of mucins and to correlate to the histologic classification. Methods Specimens were retrospectively collected from thirteen patients who underwent esophageal resection due to adenocarcinoma in BE. Sections were scored for the grade of intestinal metaplasia. The tissues were examined by immunohistochemistry for MUC2 and MUC5AC antibodies. Results Eleven patients were men. The mean age was 61 years old (varied from 40 to 75 years old. The tumor size had a mean of 4.7 ± 2.3 cm, and the extension of BE had a mean of 7.7 ± 1.5 cm. Specialized epithelium with intestinal metaplasia was present in all adjacent mucosas. Immunohistochemistry for MUC2 showed immunoreactivity in goblet cells, while MUC5AC was extensively expressed in the columnar gastric cells, localizing to the surface epithelium and extending to a variable degree into the glandular structures in BE. Tumors were classified according to the mucins in gastric type in 7/13 (MUC5AC positive and intestinal type in 4/13 (MUC2 positive. Two tumors did not express MUC2 or MUC5AC proteins. The pattern of mucin predominantly expressed in the adjacent epithelium was associated to the mucin expression profile in the tumors, p = 0.047. Conclusion Barrett's esophagus adenocarcinoma shows either gastric or intestinal type pattern of mucin expression. The two types of tumors developed in Barrett's esophagus may reflect the original cell type involved in the malignant transformation.

  19. Compound-specific amino acid δ15N patterns in marine algae: Tracer potential for cyanobacterial vs. eukaryotic organic nitrogen sources in the ocean

    Science.gov (United States)

    McCarthy, Matthew D.; Lehman, Jennifer; Kudela, Raphael

    2013-02-01

    Stable nitrogen isotopic analysis of individual amino acids (δ15N-AA) has unique potential to elucidate the complexities of food webs, track heterotrophic transformations, and understand diagenesis of organic nitrogen (ON). While δ15N-AA patterns of autotrophs have been shown to be generally similar, prior work has also suggested that differences may exist between cyanobacteria and eukaryotic algae. However, δ15N-AA patterns in differing oceanic algal groups have never been closely examined. The overarching goals of this study were first to establish a more quantitative understanding of algal δ15N-AA patterns, and second to examine whether δ15N-AA patterns have potential as a new tracer for distinguishing prokaryotic vs. eukaryotic N sources. We measured δ15N-AA from prokaryotic and eukaryotic phytoplankton cultures and used a complementary set of statistical approaches (simple normalization, regression-derived fractionation factors, and multivariate analyses) to test for variations. A generally similar δ15N-AA pattern was confirmed for all algae, however significant AA-specific variation was also consistently identified between the two groups. The relative δ15N fractionation of Glx (glutamine + glutamic acid combined) vs. total proteinaceous N appeared substantially different, which we hypothesize could be related to differing enzymatic forms. In addition, the several other AA (most notably glycine and leucine) appeared to have strong biomarker potential. Finally, we observed that overall patterns of δ15N values in algae correspond well with the Trophic vs. Source-AA division now commonly used to describe variable AA δ15N changes with trophic transfer, suggesting a common mechanistic basis. Overall, these results show that autotrophic δ15N-AA patterns can differ between major algal evolutionary groupings for many AA. The statistically significant multivariate results represent a first approach for testing ideas about relative eukaryotic vs. prokaryotic

  20. Fluctuations in Blood Marginal Zone B-Cell Frequencies May Reflect Migratory Patterns Associated with HIV-1 Disease Progression Status.

    Science.gov (United States)

    Gauvin, Julie; Chagnon-Choquet, Josiane; Poudrier, Johanne; Roger, Michel

    2016-01-01

    We have previously shown that overexpression of BLyS/BAFF was associated with increased relative frequencies of innate "precursor" marginal zone (MZ)-like B-cells in the blood of HIV-1-infected rapid and classic progressors. However, along with relatively normal BLyS/BAFF expression levels, these cells remain unaltered in elite-controllers (EC), rather, percentages of more mature MZ-like B-cells are decreased in the blood of these individuals. Fluctuations in frequencies of blood MZ-like B-cell populations may reflect migratory patterns associated with disease progression status, suggesting an important role for these cells in HIV-1 pathogenesis. We have therefore longitudinally measured plasma levels of B-tropic chemokines by ELISA-based technology as well as their ligands by flow-cytometry on blood B-cell populations of HIV-1-infected individuals with different rates of disease progression and uninfected controls. Migration potential of B-cell populations from these individuals were determined by chemotaxis assays. We found important modulations of CXCL13-CXCR5, CXCL12-CXCR4/CXCR7, CCL20-CCR6 and CCL25-CCR9 chemokine-axes and increased cell migration patterns in HIV progressors. Interestingly, frequencies of CCR6 expressing cells were significantly elevated within the precursor MZ-like population, consistent with increased migration in response to CCL20. Although we found little modulation of chemokine-axes in EC, cell migration was greater than that observed for uninfected controls, especially for MZ-like B-cells. Overall the immune response against HIV-1 may involve recruitment of MZ-like B-cells to peripheral sites. Moreover, our findings suggest that "regulated" attraction of these cells in a preserved BLyS/BAFF non-inflammatory environment, such as encountered in EC could be beneficial to the battle and even control of HIV.

  1. Ileal endogenous nitrogen recovery is increased and its amino acid pattern is altered in pigs fed quebracho extract

    NARCIS (Netherlands)

    Steendam, C.A.; Tamminga, S.; Boer, H.; Jong, de E.J.; Visser, G.H.; Verstegen, M.W.A.

    2004-01-01

    Ileal endogenous nitrogen recovery (ENR) in pigs (9 ± 0.6 kg body weight) was estimated simultaneously using the 15N-isotope dilution technique (15N-IDT) and the peptide alimentation ultrafiltration (UF) method. Diets were cornstarch, enzyme-hydrolyzed casein with no (control) or high (4%) content

  2. Ileal endogenous nitrogen recovery is increased and its amino acid pattern is altered in pigs fed quebracho extract

    NARCIS (Netherlands)

    Steendam, C.A.C.; Tamminga, S.; Boer, H.; de Jong, E.J.; Visser, G.H.; Verstegen, M.W.A.

    2004-01-01

    lleal endogenous nitrogen recovery (ENR) in pigs (9 +/- 0.6 kg body weight) was estimated simultaneously using the N-15-isotope dilution technique (N-15-IDT) and the peptide alimentation ultrafiltration (UF) method. Diets were cornstarch, enzyme-hydrolyzed casein with no (control) or high (4%)

  3. Nitrogen patterns in subsurface waters of the Yzeron stream: effect of combined sewer overflows and subsurface-surface water mixing.

    Science.gov (United States)

    Aucour, A M; Bariac, T; Breil, P; Namour, P; Schmitt, L; Gnouma, R; Zuddas, P

    2013-01-01

    Urbanization subjects streams to increased nitrogen loads. Therefore studying nitrogen forms at the interface between urban stream and groundwater is important for water resource management. In this study we report results on water δ(18)O and nitrogen forms in subsurface waters of a stream (Yzeron, France). The sites studied were located upstream and downstream of combined sewer overflows (CSO) in a rural area and a periurban area, respectively. Water δ(18)O allowed us to follow the mixing of subsurface water with surface water. Dissolved organic nitrogen and organic carbon of fine sediment increased by 20-30% between rural and periurban subsurface waters in the cold season, under high flow. The highest nitrate levels were observed in rural subsurface waters in the cold season. The lowest nitrate levels were found in periurban subsurface waters in the warm season, under low flow. They corresponded to slow exchange of subsurface waters with channel water. Thus reduced exchange between surface and subsurface waters and organic-matter-rich input seemed to favor nitrate reduction in the downstream, periurban, subsurface waters impacted by CSO.

  4. Nitrogen isotopic patterns of vegetation as affected by breeding activity of Black-tailed Gull (Larus crassiostris): A coupled analysis of feces, inorganic soil nitrogen and flora

    International Nuclear Information System (INIS)

    Mizota, C.

    2009-01-01

    Two currently breeding colonies (Matsushima Bay and Rishiri island; northern Japan) of predominant Black-tailed Gull (Larus crassiostris) were studied for N isotopic patterns of flora, which is affected by increased supply of inorganic soil N derived from the microbial transformation of feces. Coupled samples of feces, topsoil and flora were collected in early to mid July (2008), when input of fecal N onto soils was at its maximum. As bird migration and breeding continued, native Japanese red-pine (Pinus densiflora), junipers (Juniperus chinensis and Juniperus rigita; Matsushima Bay colony) and Sasa senanensis (Rishiri colony) declined, while ornithocoprophilus exotic plants succeeded. Among tree species on the islands, P. densiflora with ectomycorrizal colonization appears highly susceptible to elevated concentrations of NH 4 -N in the topsoil. A mechanism for best explaining the plant succession associated with the breeding activity of Black-tailed Gull was evidenced by two parameters: first, concomitant elevation of N content in the flora and second, inorganic soil N content, along with changes in N isotopic composition (δ 15 N). Earlier isotopic data on the foliar N affected by breeding activity were compiled and reviewed. Emphasis was put on isotopic information for inorganic N in soils that controls plant succession.

  5. The Effect of Feeding Calliandra Calothyrus in Different Patterns as a Supplement to Rhodes Grass Hay on Intake, Nitrogen Utilization and Milk Yield of dual Purpose Goats

    International Nuclear Information System (INIS)

    Kariuki, J.N.

    2002-01-01

    Eighteen dual purpose goats were used to evaluate the effects of feeding Calliandra caryothyrus leaf meal at different patterns as a supplement to Rhodes grass hay on intake, nitrogen utilization and milk yield. A basal diet of low quality Rhodes grass hay (fed at 90% ad libitum) and 100 g maize germ were offered to the goats over a 60-day experimental period. The treatments were:- (T1) 100 g day -1 calliandra for 60 days; (T2) 200 g day -1 calliandra for 30 days followed by another 30 days where 200 g or 0 g day -1 calliandra were alternated every 5 days; and (T3) 200 g or 0 g day -1 alternated every 5 days for 60 days. Total dry matter intake (DMI) was significantly (p -1 for T1, T2 and T3, respectively.Milk Yields had similar trend and averaged 166.1, 231.8 and 201.1 g day -1 for T1, T2, and T3, respectively. The utilization of nitrogen was also significantly (p<0.05) affected by pattern of supplement feeding. It was concluded from the results that the overall animal response could be influenced by how a limited quantity of supplement was fed

  6. Altered precipitation patterns and simulated nitrogen deposition effects on phenology of common plant species in a Tibetan Plateau alpine meadow

    Science.gov (United States)

    The interactive effects of five seasonal precipitation distribution patterns and two levels of N deposition (ambient and doubled) on phenological traits of six dominant plant species were studied in an alpine meadow of the Tibetan Plateau for two consecutive years. Seasonal precipitation patterns i...

  7. Increased temperature causes different carbon and nitrogen processing patterns in two common intertidal foraminifera (Ammonia tepida and Haynesina germanica

    Directory of Open Access Journals (Sweden)

    J. Wukovits

    2017-06-01

    Full Text Available Benthic foraminifera are highly abundant heterotrophic protists in marine sediments, but future environmental changes will challenge the tolerance limits of intertidal species. Metabolic rates and physiological processes in foraminifera are strongly dependent on environmental temperatures. Temperature-related stress could therefore impact foraminiferal food source processing efficiency and might result in altered nutrient fluxes through the intertidal food web. In this study, we performed a laboratory feeding experiment on Ammonia tepida and Haynesina germanica, two dominant foraminiferal species of the German Wadden Sea/Friedrichskoog, to test the effect of temperature on phytodetritus retention. The specimens were fed with 13C and 15N labelled freeze-dried Dunaliella tertiolecta (green algae at the start of the experiment and were incubated at 20, 25 and 30 °C respectively. Dual labelling was applied to observe potential temperature effects on the relation of phytodetrital carbon and nitrogen retention. Samples were taken over a period of 2 weeks. Foraminiferal cytoplasm was isotopically analysed to investigate differences in carbon and nitrogen uptake derived from the food source. Both species showed a positive response to the provided food source, but carbon uptake rates of A. tepida were 10-fold higher compared to those of H. germanica. Increased temperatures had a far stronger impact on the carbon uptake of H. germanica than on A. tepida. A distinct increase in the levels of phytodetrital-derived nitrogen (compared to more steady carbon levels could be observed over the course of the experiment in both species. The results suggest that higher temperatures have a significant negative effect on the carbon exploitation of H. germanica. For A. tepida, higher carbon uptake rates and the enhanced tolerance range for higher temperatures could outline an advantage in warmer periods if the main food source consists of chlorophyte phytodetritus

  8. Increased temperature causes different carbon and nitrogen processing patterns in two common intertidal foraminifera (Ammonia tepida and Haynesina germanica)

    Science.gov (United States)

    Wukovits, Julia; Enge, Annekatrin Julie; Wanek, Wolfgang; Watzka, Margarete; Heinz, Petra

    2017-06-01

    Benthic foraminifera are highly abundant heterotrophic protists in marine sediments, but future environmental changes will challenge the tolerance limits of intertidal species. Metabolic rates and physiological processes in foraminifera are strongly dependent on environmental temperatures. Temperature-related stress could therefore impact foraminiferal food source processing efficiency and might result in altered nutrient fluxes through the intertidal food web. In this study, we performed a laboratory feeding experiment on Ammonia tepida and Haynesina germanica, two dominant foraminiferal species of the German Wadden Sea/Friedrichskoog, to test the effect of temperature on phytodetritus retention. The specimens were fed with 13C and 15N labelled freeze-dried Dunaliella tertiolecta (green algae) at the start of the experiment and were incubated at 20, 25 and 30 °C respectively. Dual labelling was applied to observe potential temperature effects on the relation of phytodetrital carbon and nitrogen retention. Samples were taken over a period of 2 weeks. Foraminiferal cytoplasm was isotopically analysed to investigate differences in carbon and nitrogen uptake derived from the food source. Both species showed a positive response to the provided food source, but carbon uptake rates of A. tepida were 10-fold higher compared to those of H. germanica. Increased temperatures had a far stronger impact on the carbon uptake of H. germanica than on A. tepida. A distinct increase in the levels of phytodetrital-derived nitrogen (compared to more steady carbon levels) could be observed over the course of the experiment in both species. The results suggest that higher temperatures have a significant negative effect on the carbon exploitation of H. germanica. For A. tepida, higher carbon uptake rates and the enhanced tolerance range for higher temperatures could outline an advantage in warmer periods if the main food source consists of chlorophyte phytodetritus. These conditions are

  9. Linking foraging strategies of marine calanoid copepods to patterns of nitrogen stable isotope signatures in a mesocosm study

    DEFF Research Database (Denmark)

    Sommer, Frank; Saage, A.; Santer, B.

    2005-01-01

    foraging mode and, further, with its nitrogen stable isotope signature (delta(15)N). This is because a more carnivorous diet may be expected to result in a higher delta(15)N. We tested this hypothesis in a mesocosm study using a density gradient (0 to 80 ind. 1(-1)) of calanoid copepods. We expected......The foraging modes of calanoid copepods differ in that stationary suspension-feeding is more easily detected by prey with strong escape responses (ciliates) than is 'cruising' or 'ambushing' feeding. Thus, the ability of a copepod to include heterotrophic prey in its diet may be associated with its...

  10. Effect of Different Planting Methods of Onion (Allium cepa L. and Nitrogen Rate on Onion Growth Pattern under Interference with Purple Nutsedge (Cyperus rotundus

    Directory of Open Access Journals (Sweden)

    N Karimi Arpnahy

    2016-07-01

    Full Text Available Introduction Human always has looked for improving food production through increasing crops yield. In this path, weeds through competition with crop for environmental factors and inputs have reduced the quantity and quality of crop products. Competition for nitrogen absorption not only is the most common form of intra-specific competition amongst crop plants, but also is the most popular form of inter-specific competition in the system of weed-crop interference. Therefore, understanding the method of nitrogen absorption and its allocation in competing plants, will be a key tool to improve weed management strategies. Materials and Methods In order to study the effect of sowing method and nitrogen rate on the growth pattern of onion under interference with purple nutsedge, a factorial experiment based on a randomized complete block design was conducted with three replications at the Research Greenhouse of University of Birjand in 2013. The first factor included three sowing methods of onion (seed sowing, onion set and transplanting and the second factor consisted of three levels of nitrogen (50, 100 and 150 kg N ha-1, equivalent of 25, 50 and 75 mg N kg-1 soil that urea fertilizer with a purity of 46% was used for this purpose. Results and Discussion The results of the analysis of variance showed that nitrogen levels had significant effects on plant height, leaf area index as well as aboveground and bulb dry weights. Furthermore, sowing methods revealed significant effects on plant height, leaf number, leaf area index as well as aboveground and bulb dry weights. Moreover, the interaction between sowing methods and levels of nitrogen had a significant effect on plant height, leaf area index and aboveground dry weight, while it had no significant effect on leaf number and bulb dry weight. The results of the comparisons of the means of onion planting methods and nitrogen levels interactions confirmed that the superiority of the influence of onion set

  11. Regional gradients in surface sediment nitrogen isotopes as a reflection of nutrient cycling and oxygen deficiency in upwelling areas off Peru and Namibia (Invited)

    Science.gov (United States)

    Schneider, R. R.; Mollier-Vogel, E.; Martinez, P.

    2010-12-01

    The sedimentary d15N signal is commonly considered as a reflection of the marine nutrient cycling and related biochemical processes in the overlying water masses. In the modern ocean all processes together result in a mean d15N value of about 5 to 6 per mill for dissolved nitrate. Deviations from this value are considered as a product mainly of nitrogen fixation and nitrate supply causing lower values, while nitrate utilization and denitrification, as well as organic matter degradation tend to shift the signal to higher values. As denitrification is only occurring under conditions of strong oxygen limitation in the water column outstandingly high d15N values in sediment records are commonly taken as indirect evidence for strong oxygen minimum conditions in the past. By comparing surface sediment values from coastal upwelling areas off Namibia and Peru, we test whether such an approach is applicable. Only the Peruvian system is characterized by a pronounced oxygen minimum zone (OMZ) that extends across the shelf and slope far into the Eastern Equatorial Pacific. For comparison we present new results for the Peruvian margin between 2°N and 20°S within and below the Peruvian OMZ in combination with a similar data set from the Namibian margin with an OMZ restricted to the inner shelf. The Peruvian sediment data is furthermore compared to d15N of dissolved nitrate in the overlying water column to better understand how regional oceanography effects the water column d15N and thus the sediment surface signal. Productivity and nitrate uptake is maximal at the position of local and perennial upwelling cells in both systems. However, due to continuous nutrient supply into the upwelling systems sedimentary d15N values on the outer shelves and slopes reveal an increase of only about 2 to 3 per mill over the mean ocean value. Only where extreme oxygen deficiency occurs, as off Peru between 10 and 20 S, the sedimentary d15N signal reaches very high values above 10 per mill

  12. [Characteristics and Transport Patterns of Ammonia, Nitrites, Nitrates and Inorganic Nitrogen Flux at Epikarst Springs and a Subterranean Stream in Nanshan, Chongqing].

    Science.gov (United States)

    Zhang, Yuan-zhu; He, Qiu-fang; Jiang, Yong-jun; Li, Yong

    2016-04-15

    In a karst groundwater system, it develops complex multiple flows because of its special geological structure and unique physical patterns of aquifers. In order to investigate the characteristics and transport patterns of ammonia, nitrite and nitrate in epikarst water and subterranean stream, the water samples were collected monthly in a fast-urbanizing karst region. The results showed distinctive characteristics of three forms of inorganic nitrogen. The concentration of inorganic nitrogen was stable in the epikarst water while it was fluctuant in the subterranean stream. Epikarst water was less affected by rainfall and sewage compared with subterranean stream. In epikarst water, the nitrate concentration was much higher than the ammonia concentration. Dissolved inorganic nitrogen, mainly from non-point source pollution related to agricultural activities, passed in and out of the epikarst water based on a series of physical; chemical and biological processes in the epikarst zone, such as ammonification, adsorption and nitrification. On the contrary, subterranean stream showed a result of NH₄⁺-N > NO₃⁻-N in dry seasons and NO₃⁻-N > NH₄⁺-N in rainy seasons. This can be due to the fact that sanitary and industrial sewage flowed into subterranean river through sinkholes, fissures and grikes in dry season. Dissolved inorganic nitrogen in subterranean river was mainly from the non-point source pollution in wet season. Non-point source pollutants entered into subterranean water by two transport ways, one by penetration along with vadose flow through fissures and grikes, and the other by conduit flow through sinkholes from the surface runoff, soil water flow and epikarst flow. The export flux of DIN was 56.05 kg · (hm² · a)⁻¹, and NH₄⁺-N and NO₃⁻-N accounted for 46.03% and 52.51%, respectively. The contributions of point-source pollution and non point-source pollution to the export flux of DIN were 25.08% and 74.92%, respectively, based on run

  13. Sensitivity of growth and biomass allocation patterns to increasing nitrogen: a comparison between ephemerals and annuals in the Gurbantunggut Desert, north-western China.

    Science.gov (United States)

    Zhou, Xiaobing; Zhang, Yuanming; Niklas, Karl J

    2014-02-01

    Biomass accumulation and allocation patterns are critical to quantifying ecosystem dynamics. However, these patterns differ among species, and they can change in response to nutrient availability even among genetically related individuals. In order to understand this complexity further, this study examined three ephemeral species (with very short vegetative growth periods) and three annual species (with significantly longer vegetative growth periods) in the Gurbantunggut Desert, north-western China, to determine their responses to different nitrogen (N) supplements under natural conditions. Nitrogen was added to the soil at rates of 0, 0.5, 1.0, 3.0, 6.0 and 24.0 g N m(-2) year(-1). Plants were sampled at various intervals to measure relative growth rate and shoot and root dry mass. Compared with annuals, ephemerals grew more rapidly, increased shoot and root biomass with increasing N application rates and significantly decreased root/shoot ratios. Nevertheless, changes in the biomass allocation of some species (i.e. Erodium oxyrrhynchum) in response to the N treatment were largely a consequence of changes in overall plant size, which was inconsistent with an optimal partitioning model. An isometric log shoot vs. log root scaling relationship for the final biomass harvest was observed for each species and all annuals, while pooled data of three ephemerals showed an allometric scaling relationship. These results indicate that ephemerals and annuals differ observably in their biomass allocation patterns in response to soil N supplements, although an isometric log shoot vs. log root scaling relationship was maintained across all species. These findings highlight that different life history strategies behave differently in response to N application even when interspecific scaling relationships remain nearly isometric.

  14. Geomorphology and reflectance patterns of vegetation-covered dunes at the Tsodilo Hills, north-west Botswana

    Science.gov (United States)

    Jacobberger, P. A.; Hooper, D. M.

    1991-01-01

    Seasonal reflectance variations in semigrid environments provide a means of assessing vegetation health and density as well as monitoring landform processes. Multitemporal Landsat Thematic Mapper scenes with field measurements are used to map geomorphology and vegetation density in a stabilized dune environment and to measure seasonal reflectance changes for a series of ten geomorphological and vegetation units on the Kalahari-age linear dunes. Units were chosen based on differences in landform and proportion of trees, forbs and bare soil. Reflectance curves and normalized-difference vegetation indices (NDVI) show that dune crests have the strongest seasonal variability in color and brightness. The geomorphological link with reflectance and NDVI values are linked to biomass production and zoning of vegetation with slope, drainage and subtle soil differences.

  15. Near-Horizontal, Two-Phase Flow Patterns of Nitrogen and Hydrogen at Low Mass Heat and Flux (on CD-ROM)

    Science.gov (United States)

    VanDresar, N. T.; Siegwarth, J. D.

    2001-01-01

    One reason for NASA's interest in cryogenic two-phase flow with low mass and heat flux is the need to design spacecraft heat exchangers used for vaporizing cryogenic propellants. The CD-ROM provides digitized movies of particular flow patterns observed in experimental work. The movies have been provided in (QuickTime9Trademark) format, encoded at 320w x 240h pixels, 15 fps, using the Sorenson(Trademark) Video Codec for compression. Experiments were conducted to obtain data on the two-phase (liquid and vapor) flow behavior of cryogenic nitrogen and hydrogen under low mass and heat flux conditions. Tests were performed in normal gravity with a 1.5 degree up flow configuration. View ports in the apparatus permitted visual observation of the two-phase flow patterns. Computer codes to predict flow patterns were developed from theoretical/empirical models reported in the literature. Predictions from the computer codes were compared with experimental flow pattern observations. Results are presented employing the traditional two-dimensional flow pattern map format using the liquid and gas superficial velocities as coordinates. In general, the agreement between the experimental results and the analytical predictive methods is reasonably good. Small regions of the flow pattern maps are identified where the models are deficient as a result of neglecting phase change phenomena. Certain regions of the maps were beyond the range of the experiments and could not be completely validated. Areas that could benefit from further work include modeling of the transition from separated flow, collection of additional data in the bubble and annular flow regimes, and collection of experimental data at other inclination angles, tube diameters and high heat flux.

  16. Spatial pattern of soil organic carbon and total nitrogen, and analysis of related factors in an agro-pastoral zone in Northern China

    Science.gov (United States)

    Wang, Xuyang; Chen, Yinping; Lian, Jie; Luo, Yongqing; Niu, Yayi; Gong, Xiangwen

    2018-01-01

    The spatial pattern of soil organic carbon (SOC) and total nitrogen (TN) densities plays a profound important role in estimating carbon and nitrogen budgets. Naiman Banner located in northern China was chosen as research site, a total of 332 soil samples were taken in a depth of 100 cm from the low hilly land in the southern part, sandy land in the middle part and an alluvial plain in the northern part of the county. The results showed that SOC and TN density initially decreased and then increased from the north to the south, The highest densities, were generally in the south, with the lowest generally in the middle part. The SOC and TN densities in cropland were significantly greater than those in woodland and grassland in the alluvial plains and for Naiman as a whole. The woodland SOC and TN density were higher than those of grassland in the low hilly land, and higher densities of SOC and TN in grassland than woodland in the sandy land and low hilly land. There were significant differences in SOC and TN densities among the five soil types of Cambisols, Arenosols, Gleysols, Argosols, and Kastanozems. In addition, SOC and TN contents generally decreased with increasing soil depth, but increased below a depth of 40 cm in the Cambisols and became roughly constant at this depth in the Kastanozems. There is considerable potential to sequester carbon and nitrogen in the soil via the conversion of degraded sandy land into woodland and grassland in alluvial plain, and more grassland should be established in sandy land and low hilly land. PMID:29771979

  17. Characterization of Nitrogen Uptake Pattern in Malaysian Rice MR219 at Different Growth Stages Using 15N Isotope

    Directory of Open Access Journals (Sweden)

    Mohammad Mu’az Hashim

    2015-09-01

    Full Text Available Nitrogen (N use efficiency is usually less than 50%, and it remains a major problem in rice cultivation. Controlled release fertilizer (CRF technology is one of the well-known efforts to overcome this problem. The efficiency of CRF, however, is very much dependent on the timing of nutrient release. This study was conducted to determine the precise time of N uptake by rice as a guideline to develop efficient CRF. Fertilizer N uptake by rice at different growth stages was investigated by using 15N isotopic technique. Rice was planted in pots, with 15N urea as N source at the rate of 120 kg/hm2. Potassium and phosphorus were applied at the same rate of 50 kg/hm2. Standard agronomic practices were employed throughout the growing periods. Rice plants were harvested every two weeks until maturation at the 14th week and analyzed for total N and 15N content. Nitrogen derived from fertilizer was calculated. Total N uptake in plants consistently increased until the 11th week. After that, it started to plateau and finally declined. Moreover, N utilization by rice plants peaked at 50%, which occurred during the 11th week after transplanting. N derived from fertilizer in rice plants were in the range of 18.7% to 40.0% in all plant tissues. The remaining N was derived from soil. Based on this study, N release from CRF should complete by the 11th week after planting to ensure the maximum fertilizer N uptake by rice plants. Efficient CRF should contribute to higher N derived from fertilizer which also resultedin a higher total N uptake by rice plants, increasing the potential of rice to produce higher yield while at the same time of reducing loss.

  18. Near-Horizontal, Two-Phase Flow Patterns of Nitrogen and Hydrogen at Low Mass Heat and Flux Supplement

    Science.gov (United States)

    VanDresar, Neil T.; Siegwarth, James D.

    2001-01-01

    This CD is a companion to NASA/TP-2001-210380. It contains digitized movies of particular flow patterns observed in experimental work. The movies have been provided in QuickTime format, encoded at 320w x 240h pixels, 15 fps, using the Sorenson Video Codec for compression.

  19. Effects of nitrogen on temporal and spatial patterns of nitrate in streams and soil solution of a central hardwood forest

    Science.gov (United States)

    Frank S. Gilliam; Mary Beth. Adams

    2011-01-01

    This study examined changes in stream and soil water NO3- and their relationship to temporal and spatial patterns of NO3- in soil solution of watersheds at the Fernow Experimental Forest, West Virginia. Following tenfold increases in stream NO3

  20. Spatial and temporal patterns of nitrogen isotopic composition of ammonia at U.S. ammonia monitoring network sites

    Science.gov (United States)

    Felix, J. David; Elliott, Emily M.; Gay, David A.

    2017-02-01

    Ammonia (NH3) emissions and ammonium (NH4+) deposition can have harmful effects on the environment and human health but remain generally unregulated in the U.S. PM2.5 regulations require that an area not exceed an annual average PM2.5 value of 12 μg/m3 (averaged over three years), and since NH3 is a significant precursor to PM2.5 formation these are the closest indirect regulations of NH3 emissions in the U.S. If the U.S. elects to adopt NH3 emission regulations similar to those applied by the European Union, it will be imperative to first adequately quantify NH3 emission sources and transport, and also understand the factors causing varying emissions from each source. To further investigate NH3 emission sources and transport at a regional scale, NH3 was sampled monthly at a subset of nine Ammonia Monitoring Network (AMoN) sites and analyzed for nitrogen isotopic composition of NH3 (δ15N-NH3). The observed δ15N-NH3 values ranged from -42.4 to +7.1‰ with an average of -15.1 ± 9.7. The observed δ15N-NH3 values reported here provide insight into the spatial and temporal trends of the NH3 sources that contribute to ambient [NH3] in the U.S. In regions where agriculture is prevalent (i.e., U.S. Midwest), low and seasonally variable δ15N-NH3 values are observed and are associated with varying agricultural sources. In comparison, rural nonagricultural areas have higher and more seasonally consistent δ15N-NH3 values associated with a constant "natural" (e.g. soil, vegetation, bi-directional flux, ocean) NH3 source. With regards to temporal variation, the peak in U.S. spring agricultural activity (e.g. fertilizer application, livestock waste volatilization) is accompanied by a decrease in δ15N-NH3 values at a majority of the sites, whereas higher δ15N-NH3 values in other seasons could be due to shifting sources (e.g. coal-fired power plants) and/or fractionation scenarios. Fractionation processes that may mask NH3 source signatures are discussed and require

  1. [Research on the influence of urban land use structure and pattern on nitrogen, phosphorus of wetland water environment in Xianlin New Town of Nanjing].

    Science.gov (United States)

    Cai, Chun-Xiao; Liu, Hong-Yu; Li, Yu-Feng; Wang, Cong; Hou, Ming-Hang

    2014-08-01

    The 10 typical wetlands in Xianlin New Townof Nanjing were classified into three categories, including rural wetland, suburban wetland, and urban wetland according to the influence of urbanization as well as the characteristics of wetland and LUCC of catchment regions. RDA was used to analyse the relationships between nitrogen and phosphorus in urban wetland and various types and patterns of land use. It was found that the water quality of the urban wetlands presented to be worse than that from rural wetlands, followed by sub urban wetlands. Secondly, according to all investigated wetlands, TP and TN turned out to be higher during the wet seasons than dry seasons. In addition, significant differences of TP were observed between wet and dry seasons for rural and suburban wetlands, and it was not so obvious for urban wetlands. However, the differences of TN was opposite to that of TP. Thirdly, factors affecting the water quality of wetlands were comprised of types and patterns of land use, and thus significant positive relationships were found between the concentrations of TN and TP and the impervious land, while negative correlations for meadows, woodlands and wetlands. What's more, higher remarkable differences were found in wetlands than those from meadows and woodlands. Regarding to patterns of land use, TP, TN concentrations were negatively correlated with the average patch shape in the dry and wet seasons, whereas positively relationships were observed for patch density and diversity index; furthermore, with refer to the impact of adjacent landscape, significant relationships were found between the content of TN and the patterns of land use and thus, a negative correlation in the wet season and a positive correlation in the dry season were observed, respectively.

  2. Evaluation the Effect of Corn (Zea mays L. Sowing Pattern and Nitrogen Application Method on Herbicide Optimizing and Reducing Foramsulfuron (Equip® Dose

    Directory of Open Access Journals (Sweden)

    E. Izadi Darbandi

    2016-06-01

    Full Text Available Introduction: In the whole agro ecosystems, weeds had existence as unwanted plant that control of them is necessary. The competition between weeds and corn for moisture, light, nutrients during the growth season is induced reducing the quality and quantity of corn yield. Although the corn is high and powerful crop but is sensitive to competition with the weed and reduction of yield has been reported over 30%. Since the weeds are adapted to conditions, they are successful to completion and reducing the yield. So weed management is important in corn production. Chemical control has not been the unique and best way to manage the weeds and it reduce the sustainability of agro ecosystems. Although developing the herbicides, reduce the pressures caused by the weeds, but by developing rapidly the weed resistance to herbicides and increasing the environmental concerns and its high cost, today need to new, more immune and sustainable techniques for weed management. The main approach for sustainable weed management in an integrated weed management program is increasing crop competitiveness with weeds to reduce herbicide use. In this regard, the planting date, crop rotation, planting density, intercropping, planting pattern, fertilizer type, rate and application method are some of the most crop management strategies. Among the nutrients necessary for plants, nitrogen is the most nutrient in plant competition. Therefore, its application management plays a key role in reducing weed interference with crops and reduced herbicide use. Foramsulfuron herbicide from ALS inhibitors is a post-emergence sulfonylurea herbicide for the control of grasses and certain broadleaf weeds in maize. Unfortunately, these herbicides are also notorious for their ability to select resistant weed populations. Now, there are more weed species that are resistant to ALS-inhibiting herbicides than to any other herbicide group. In several cropping systems, ALS-inhibiting herbicides were

  3. Seasonal Patterns of Soil Respiration and Related Soil Biochemical Properties under Nitrogen Addition in Winter Wheat Field

    Science.gov (United States)

    Liang, Guopeng; Houssou, Albert A.; Wu, Huijun; Cai, Dianxiong; Wu, Xueping; Gao, Lili; Li, Jing; Wang, Bisheng; Li, Shengping

    2015-01-01

    Understanding the changes of soil respiration under increasing N fertilizer in cropland ecosystems is crucial to accurately predicting global warming. This study explored seasonal variations of soil respiration and its controlling biochemical properties under a gradient of Nitrogen addition during two consecutive winter wheat growing seasons (2013–2015). N was applied at four different levels: 0, 120, 180 and 240 kg N ha-1 year-1 (denoted as N0, N12, N18 and N24, respectively). Soil respiration exhibited significant seasonal variation and was significantly affected by soil temperature with Q10 ranging from 2.04 to 2.46 and from 1.49 to 1.53 during 2013–2014 and 2014–2015 winter wheat growing season, respectively. Soil moisture had no significant effect on soil respiration during 2013–2014 winter wheat growing season but showed a significant and negative correlation with soil respiration during 2014–2015 winter wheat growing season. Soil respiration under N24 treatment was significantly higher than N0 treatment. Averaged over the two growing seasons, N12, N18 and N24 significantly increased soil respiration by 13.4, 16.4 and 25.4% compared with N0, respectively. N addition also significantly increased easily extractable glomalin-related soil protein (EEG), soil organic carbon (SOC), total N, ammonium N and nitrate N contents. In addition, soil respiration was significantly and positively correlated with β-glucosidase activity, EEG, SOC, total N, ammonium N and nitrate N contents. The results indicated that high N fertilization improved soil chemical properties, but significantly increased soil respiration. PMID:26629695

  4. Seasonal Patterns of Soil Respiration and Related Soil Biochemical Properties under Nitrogen Addition in Winter Wheat Field.

    Science.gov (United States)

    Liang, Guopeng; Houssou, Albert A; Wu, Huijun; Cai, Dianxiong; Wu, Xueping; Gao, Lili; Li, Jing; Wang, Bisheng; Li, Shengping

    2015-01-01

    Understanding the changes of soil respiration under increasing N fertilizer in cropland ecosystems is crucial to accurately predicting global warming. This study explored seasonal variations of soil respiration and its controlling biochemical properties under a gradient of Nitrogen addition during two consecutive winter wheat growing seasons (2013-2015). N was applied at four different levels: 0, 120, 180 and 240 kg N ha(-1) year(-1) (denoted as N0, N12, N18 and N24, respectively). Soil respiration exhibited significant seasonal variation and was significantly affected by soil temperature with Q10 ranging from 2.04 to 2.46 and from 1.49 to 1.53 during 2013-2014 and 2014-2015 winter wheat growing season, respectively. Soil moisture had no significant effect on soil respiration during 2013-2014 winter wheat growing season but showed a significant and negative correlation with soil respiration during 2014-2015 winter wheat growing season. Soil respiration under N24 treatment was significantly higher than N0 treatment. Averaged over the two growing seasons, N12, N18 and N24 significantly increased soil respiration by 13.4, 16.4 and 25.4% compared with N0, respectively. N addition also significantly increased easily extractable glomalin-related soil protein (EEG), soil organic carbon (SOC), total N, ammonium N and nitrate N contents. In addition, soil respiration was significantly and positively correlated with β-glucosidase activity, EEG, SOC, total N, ammonium N and nitrate N contents. The results indicated that high N fertilization improved soil chemical properties, but significantly increased soil respiration.

  5. Distributed patterns of activity in sensory cortex reflect the precision of multiple items maintained in visual short-term memory.

    Science.gov (United States)

    Emrich, Stephen M; Riggall, Adam C; Larocque, Joshua J; Postle, Bradley R

    2013-04-10

    Traditionally, load sensitivity of sustained, elevated activity has been taken as an index of storage for a limited number of items in visual short-term memory (VSTM). Recently, studies have demonstrated that the contents of a single item held in VSTM can be decoded from early visual cortex, despite the fact that these areas do not exhibit elevated, sustained activity. It is unknown, however, whether the patterns of neural activity decoded from sensory cortex change as a function of load, as one would expect from a region storing multiple representations. Here, we use multivoxel pattern analysis to examine the neural representations of VSTM in humans across multiple memory loads. In an important extension of previous findings, our results demonstrate that the contents of VSTM can be decoded from areas that exhibit a transient response to visual stimuli, but not from regions that exhibit elevated, sustained load-sensitive delay-period activity. Moreover, the neural information present in these transiently activated areas decreases significantly with increasing load, indicating load sensitivity of the patterns of activity that support VSTM maintenance. Importantly, the decrease in classification performance as a function of load is correlated with within-subject changes in mnemonic resolution. These findings indicate that distributed patterns of neural activity in putatively sensory visual cortex support the representation and precision of information in VSTM.

  6. Seasonal patterns in immune indices reflect microbial loads on birds but not microbes in the wider environment

    NARCIS (Netherlands)

    Horrocks, N.P.C.; Matson, K.D.; Shobrak, M.; Tinbergen, J.M.; Tieleman, B.I.

    2012-01-01

    Documenting patterns in immune function is a first step to understanding immune variation, but to comprehend causes and consequences, antigen and parasite exposure that may drive such variation must be determined. We measured host-independent microbial exposure in five species of larks (Alaudidae)

  7. Hits to the left, flops to the right: different emotions during listening to music are reflected in cortical lateralisation patterns.

    Science.gov (United States)

    Altenmüller, Eckart; Schürmann, Kristian; Lim, Vanessa K; Parlitz, Dietrich

    2002-01-01

    In order to investigate the neurobiological mechanisms accompanying emotional valence judgements during listening to complex auditory stimuli, cortical direct current (dc)-electroencephalography (EEG) activation patterns were recorded from 16 right-handed students. Students listened to 160 short sequences taken from the repertoires of jazz, rock-pop, classical music and environmental sounds (each n=40). Emotional valence of the perceived stimuli were rated on a 5-step scale after each sequence. Brain activation patterns during listening revealed widespread bilateral fronto-temporal activation, but a highly significant lateralisation effect: positive emotional attributions were accompanied by an increase in left temporal activation, negative by a more bilateral pattern with preponderance of the right fronto-temporal cortex. Female participants demonstrated greater valence-related differences than males. No differences related to the four stimulus categories could be detected, suggesting that the actual auditory brain activation patterns were more determined by their affective emotional valence than by differences in acoustical "fine" structure. The results are consistent with a model of hemispheric specialisation concerning perceived positive or negative emotions proposed by Heilman [Journal of Neuropsychiatry and Clinical Neuroscience 9 (1997) 439].

  8. Effect of nutrient nitrogen on laccase production, its isozyme pattern and effluent decolorization by the fungus NIOCC No. 2a, isolated from mangrove wood

    Digital Repository Service at National Institute of Oceanography (India)

    DeSouza-Ticlo, D.; Verma, A.K.; Mathew, M.; Raghukumar, C.

    Carbon and nitrogen sources in the growth medium play an important role in the production of lignin-degrading enzymes in the white-rot basidiomyceteous fungi. The role of nutrient nitrogen sources in growth media on production of lignin...

  9. Atypical pattern of discriminating sound features in adults with Asperger syndrome as reflected by the mismatch negativity.

    Science.gov (United States)

    Kujala, T; Aho, E; Lepistö, T; Jansson-Verkasalo, E; Nieminen-von Wendt, T; von Wendt, L; Näätänen, R

    2007-04-01

    Asperger syndrome, which belongs to the autistic spectrum of disorders, is characterized by deficits of social interaction and abnormal perception, like hypo- or hypersensitivity in reacting to sounds and discriminating certain sound features. We determined auditory feature discrimination in adults with Asperger syndrome with the mismatch negativity (MMN), a neural response which is an index of cortical change detection. We recorded MMN for five different sound features (duration, frequency, intensity, location, and gap). Our results suggest hypersensitive auditory change detection in Asperger syndrome, as reflected in the enhanced MMN for deviant sounds with a gap or shorter duration, and speeded MMN elicitation for frequency changes.

  10. [Storages and distributed patterns of soil organic carbon and total nitrogen during the succession of artificial sand-binding vegetation in arid desert ecosystem].

    Science.gov (United States)

    Jia, Xiao-Hong; Li, Xin-Rong; Zhou, Yu-Yan; Li, Yuan-Shou

    2012-03-01

    Soil carbon pool acts as the largest one of carbon pools in the terrestrial ecosystem. The storages and distributed patterns of soil organic carbon (SOC) and total nitrogen (TN) evaluated accurately are helpful to predict the feedback between the terrestrial ecosystem and climate changes. Based on the data about bulk density, content of SOC and TN at 0-100 cm soil profile, the density of SOC and TN at the temporal (chronosequence of artificial vegetation) and spatial (vertical) distributed patterns have been estimated. The results indicated that storages of SOC and TN at 0-100 cm depth increased with the chronosequence of artificial vegetation. The storages of SOC and TN showed the same tendency with the succession time of artificial vegetation. Storages of SOC and TN significantly increased at the early stage of banding sand by artificially vegetation ( 25 a). The variation of storages mainly occurred in the 0-20 cm depth. The storages decreased with the soil vertical depth. At the early stage of banding sand, increase in storage included every depth (0-100 cm). Whereas, at the later stage, increase in storage at 0-20 cm depth was main, and increase in the 20-100 cm was inconspicuous. The accumulation of storage at the shallow soil depth was more notability with the succession of artificial vegetation. The distributed pattern of storage in SOC and TN has been confirmed in arid desert regions below 200 mm annual precipitation. This was beneficial to understand the carbon cycle and to predict the feedback relationship between desert ecosystem and climate changes.

  11. Determinação não destrutiva do nitrogênio total em plantas por espectroscopia de reflectância difusa no infravermelho próximo Non-destructive determination of total nitrogen in plants by diffuse reflectance near infrared spectroscopy

    Directory of Open Access Journals (Sweden)

    Kássio M. G. Lima

    2008-01-01

    Full Text Available Diffuse reflectance near-infrared (DR-NIR spectroscopy associated with partial least squares (PLS multivariate calibration is proposed for a direct, non-destructive, determination of total nitrogen in wheat leaves. The procedure was developed for an Analytical Instrumental Analysis course, carried out at the Institute of Chemistry of the State University of Campinas. The DR-NIR results are in good agreement with those obtained by the Kjeldhal standard procedure, with a relative error of less than ± 3% and the method may be used for teaching purposes as well as for routine analysis.

  12. Library of UV-Vis-NIR reflectance spectra of modern organic dyes from historic pattern-card coloured papers.

    Science.gov (United States)

    Montagner, Cristina; Bacci, Mauro; Bracci, Susanna; Freeman, Rachel; Picollo, Marcello

    2011-09-01

    An accurate characterisation of the organic dyes used in artworks, especially those made of paper, is an important factor in designing safe conservation treatments. In the case of synthetic organic dyes used in modern works of art, for example, one frequently encountered difficulty is that some of these dyes are not still commercially available. Recognizing this problem, the authors of this paper present the results of an analysis of UV-Vis-NIR fibre optic reflectance spectra of 82 samples of dyed paper prepared with 41 dyes. The samples come from a historic book, The Dyeing of Paper in the Pulp, which was published by Interessen-Gemeinschaft (I.G.) Farbenindustrie in 1925. The dyes used in the paper pulp belong to the azo compounds, acridine, anthraquinone, azine, diphenylmethane, indigoid, methine, nitro, quinoline, thiazine, triphenylmethane, sulphur and xanthene classes. Copyright © 2011 Elsevier B.V. All rights reserved.

  13. Suicide in Illinois, 2005-2010: A reflection of patterns and risks by age groups and opportunities for targeted prevention.

    Science.gov (United States)

    McLone, Suzanne G; Loharikar, Anagha; Sheehan, Karen; Mason, Maryann

    2016-10-01

    Suicide accounts for two thirds of all deaths from intentional or violence-related injury and is a leading cause of death in the United States. Patterns of suicide have been well described among high-risk groups, but few studies have compared the circumstances related to suicides across all age groups. We sought to understand the epidemiology of suicide cases in Illinois and to characterize the risks and patterns for suicide among different age groups. We used suicide data collected from the Illinois Violent Death Reporting System to assess demographics, method of suicide, circumstances, and mental health status among different age groups. Between 2005 and 2010, 3,016 suicides were reported; 692 (23%) were female, and the median age (n = 3,013) was 45 years (range, 10-98 years). The most common method/weapon types were hanging/strangulation (33%), firearm (32%) and poisoning (21%). Hanging was more common (74%) among young people aged 10 to 19 years, while firearm use was more common among elderly persons age 65 years and older (55%). The percentage of victims within an age group experiencing a crisis within two weeks before committing suicide was highest among 10- to 14-year-olds, while the risk factor of having a family member or friend die in the past 5 years was highest among older victims. The final analysis demonstrated age-related trends in suicide in Illinois, suggesting prevention programs should tailor services by age. Epidemiologic study, level IV.

  14. Alternative responses to predation in two headwater stream minnows is reflected in their contrasting diel activity patterns.

    Science.gov (United States)

    Kadye, Wilbert T; Booth, Anthony J

    2014-01-01

    Animals exhibit diel periodicity in their activity in part to meet energy requirements whilst evading predation. A competing hypothesis suggests that partitioning of diel activities is less important because animals capitalise on opportunity. To test these hypotheses we examined the diel activity patterns for two cyprinid minnows, chubbyhead barb Barbus anoplus and the Eastern Cape redfin minnow Pseudobarbus afer that both occur within headwater streams in the Eastern Cape, South Africa. Chubbyhead barbs exhibited consistent nocturnal activity based on both field and laboratory observations. Due to the absence of fish predators within its habitat, its nocturnal behaviour suggests a response to the cost associated with diurnal activity, such as predation risk by diving and wading birds. In contrast, redfin minnows showed high diurnal activity and a shoaling behaviour in the wild, whereas, in the laboratory, they showed high refuge use during the diel cycle. Despite their preference for refuge in the laboratory, they were diurnally active, a behaviour that was consistent with observations in the wild. The diurnal activity of this species suggests a response to the cost associated with nocturnal activity. Such a cost could be inferred from the presence of the longfin eel, a native predator that was active at night, whereas the daytime shoaling behaviour suggests an anti-predator mechanism to diurnal visual predators. The implications of these findings relate to the impacts associated with the potential invasions by non-native piscivores that occur in the mainstem sections. Diurnal activity patterns for redfin minnows, that are IUCN-listed as endangered, may, in part, explain their susceptibility to high predation by visual non-native piscivores, such as bass and trout. In contrast, the nocturnal habits of chubbyhead barbs suggest a probable pre-adaptation to visual predation. The likelihood of invasion by nocturnally-active sharptooth catfish Clarias gariepinus

  15. Alternative responses to predation in two headwater stream minnows is reflected in their contrasting diel activity patterns.

    Directory of Open Access Journals (Sweden)

    Wilbert T Kadye

    Full Text Available Animals exhibit diel periodicity in their activity in part to meet energy requirements whilst evading predation. A competing hypothesis suggests that partitioning of diel activities is less important because animals capitalise on opportunity. To test these hypotheses we examined the diel activity patterns for two cyprinid minnows, chubbyhead barb Barbus anoplus and the Eastern Cape redfin minnow Pseudobarbus afer that both occur within headwater streams in the Eastern Cape, South Africa. Chubbyhead barbs exhibited consistent nocturnal activity based on both field and laboratory observations. Due to the absence of fish predators within its habitat, its nocturnal behaviour suggests a response to the cost associated with diurnal activity, such as predation risk by diving and wading birds. In contrast, redfin minnows showed high diurnal activity and a shoaling behaviour in the wild, whereas, in the laboratory, they showed high refuge use during the diel cycle. Despite their preference for refuge in the laboratory, they were diurnally active, a behaviour that was consistent with observations in the wild. The diurnal activity of this species suggests a response to the cost associated with nocturnal activity. Such a cost could be inferred from the presence of the longfin eel, a native predator that was active at night, whereas the daytime shoaling behaviour suggests an anti-predator mechanism to diurnal visual predators. The implications of these findings relate to the impacts associated with the potential invasions by non-native piscivores that occur in the mainstem sections. Diurnal activity patterns for redfin minnows, that are IUCN-listed as endangered, may, in part, explain their susceptibility to high predation by visual non-native piscivores, such as bass and trout. In contrast, the nocturnal habits of chubbyhead barbs suggest a probable pre-adaptation to visual predation. The likelihood of invasion by nocturnally-active sharptooth catfish

  16. Remote sensing based mapping of leaf nitrogen and leaf area index in European landscapes using the REGularized canopy reFLECtance (REGFLEC) model

    DEFF Research Database (Denmark)

    Boegh, E.; Houborg, R.; Bienkowski, J.

    2011-01-01

    index (LAI) are important determinants of the maximum CO2 Methods/Approach uptake by plants and trees. In the EU project NitroEurope, high spatial resolution (10-20 m) remote sensing data from the HRG and HRVIR sensors onboard the SPOT satellites were acquired to derive maps of leaf N and LAI for 5...... European landscapes. The estimations of leaf N, Cab and LAI soil reflectance parameters and canopy parameters are discussed in relation to the prevailing soil types and vegetation characteristics of land cover classes across the 5 European landscapes....

  17. Longitudinal observation of treatment patterns and outcomes for patients with fibromyalgia: 12-month findings from the reflections study.

    Science.gov (United States)

    Robinson, Rebecca L; Kroenke, Kurt; Williams, David A; Mease, Philip; Chen, Yi; Faries, Douglas; Peng, Xiaomei; Hann, Danette; Wohlreich, Madelaine; McCarberg, Bill

    2013-09-01

    To describe 12-month treatment patterns and outcomes for patients starting a new medication for fibromyalgia in routine clinical practice. Data from 1,700 patients were collected at baseline and 1, 3, 6, and 12 months. Repeated measures and Poisson regression models controlling for demographic, clinical, and baseline outcomes were used to assess changes in health outcomes (Brief Pain Inventory severity and interference, Sheehan Disability Scale, Fibromyalgia Impact Questionnaire), satisfaction, and economic factors for patients who initiated on pregabalin (214, 12.6%), duloxetine (264, 15.5%), milnacipran (134, 7.9%), or tricyclic antidepressants (66, 3.9%). Sensitivity analyses were run using propensity-matched cohorts. Patients started on 145 unique drugs for fibromyalgia, and over 75% of patients took two or more medications concurrently for fibromyalgia at each time point assessed. Overall, patients showed improvement on the four health outcomes, with few differences across medication cohorts. At baseline, patients reported annual averages of 20.3 visits for outpatient care, 27.7 missed days of work, and 32.6 days of care by an unpaid caregiver. The duloxetine and milnacipran (vs pregabalin or tricyclic antidepressant) cohorts had fewer outpatient visits during the 12-month study. Patients reported satisfaction with overall treatment and their fibromyalgia medication (46.0% and 42.8%, respectively). In this real-world setting, patients with fibromyalgia reported modest improvements, high resource, and medication use, and were satisfied with the care they received. Cohort differences were difficult to discern because of the high rates of drug discontinuation and concomitant medication use over the 12-month study period. Wiley Periodicals, Inc.

  18. Growth patterns reflect response to antiretroviral therapy in HIV-positive infants: potential utility in resource-poor settings.

    Science.gov (United States)

    Benjamin, D K; Miller, W C; Ryder, R W; Weber, D J; Walter, E; McKinney, R E

    2004-01-01

    Laboratory monitoring of HIV-infected children is the current standard of care in the United States to guide the appropriate use of antiretroviral therapy (ART). Although ART is becoming a reality in some developing countries, laboratory monitoring of ART is costly, necessitating creative approaches to monitoring. As an initial step to guide monitoring of HIV progression in low resource settings, we assessed the utility of the physical examination to predict clinical progression of HIV. We conducted a retrospective cohort study of HIV-infected children using data from Pediatric AIDS Clinical Trials Group Protocol 300. We developed a clinical predictive model, and compared the utility of the clinical model to the change in HIV RNA viral load as diagnostic tests of ART failure. The clinical model incorporated treatment regimen, age, and height velocity: a three-level clinical predictive model provided likelihood ratios of 0.3, 3.9, and 14. For decline in RNA the likelihood ratios were 0.2 (> 1 log decline), 1.4, and 3.5 (> log increase). We developed a simple clinical predictive model that was able to predict clinical progression of HIV after initiation of new ART. The clinical model performed similarly to using changes in HIV RNA viral load. These data should be validated internationally and prospectively, because the test subjects were from a resource rich environment and growth patterns in undernourished children may be impacted differently by HIV and its treatment. The model was most pertinent to children 36 months of age or younger, and was conducted in children receiving monotherapy and dual therapy.

  19. Radar-based rainfall estimation: Improving Z/R relations through comparison of drop size distributions, rainfall rates and radar reflectivity patterns

    Science.gov (United States)

    Neuper, Malte; Ehret, Uwe

    2014-05-01

    The relation between the measured radar reflectivity factor Z and surface rainfall intensity R - the Z/R relation - is profoundly complex, so that in general one speaks about radar-based quantitative precipitation estimation (QPE) rather than exact measurement. Like in Plato's Allegory of the Cave, what we observe in the end is only the 'shadow' of the true rainfall field through a very small backscatter of an electromagnetic signal emitted by the radar, which we hope has been actually reflected by hydrometeors. The meteorological relevant and valuable Information is gained only indirectly by more or less justified assumptions. One of these assumptions concerns the drop size distribution, through which the rain intensity is finally associated with the measured radar reflectivity factor Z. The real drop size distribution is however subject to large spatial and temporal variability, and consequently so is the true Z/R relation. Better knowledge of the true spatio-temporal Z/R structure therefore has the potential to improve radar-based QPE compared to the common practice of applying a single or a few standard Z/R relations. To this end, we use observations from six laser-optic disdrometers, two vertically pointing micro rain radars, 205 rain gauges, one rawindsonde station and two C-band Doppler radars installed or operated in and near the Attert catchment (Luxembourg). The C-band radars and the rawindsonde station are operated by the Belgian and German Weather Services, the rain gauge data was partly provided by the French, Dutch, Belgian, German Weather Services and the Ministry of Agriculture of Luxembourg and the other equipment was installed as part of the interdisciplinary DFG research project CAOS (Catchment as Organized Systems). With the various data sets correlation analyzes were executed. In order to get a notion on the different appearance of the reflectivity patterns in the radar image, first of all various simple distribution indices (for example the

  20. Different patterns of cytokines and chemokines combined with IFN-γ production reflect Mycobacterium tuberculosis infection and disease.

    Directory of Open Access Journals (Sweden)

    Yang Yu

    Full Text Available BACKGROUND: IFN-γ is presently the only soluble immunological marker used to help diagnose latent Mycobacterium tuberculosis (M.tb infection. However, IFN-γ is not available to distinguish latent from active TB infection. Moreover, extrapulmonary tuberculosis, such as tuberculous pleurisy, cannot be properly diagnosed by IFN-γ release assay. As a result, other disease- or infection-related immunological biomarkers that would be more effective need to be screened and identified. METHODOLOGY: A panel of 41 soluble immunological molecules (17 cytokines and 24 chemokines was tested using Luminex liquid array-based multiplexed immunoassays. Samples, including plasma and pleural effusions, from healthy donors (HD, n = 12 or patients with latent tuberculosis infection (LTBI, n = 20, pulmonary tuberculosis (TB, n = 12, tuberculous pleurisy (TP, n = 15 or lung cancer (LC, n = 15 were collected and screened for soluble markers. Peripheral blood mononuclear cells (PBMCs and pleural fluid mononuclear cells (PFMCs were also isolated to investigate antigen-specific immune factors. PRINCIPAL FINDINGS: For the 41 examined factors, our results indicated that three patterns were closely associated with infection and disease. (1 Significantly elevated plasma levels of IL-2, IP-10, CXCL11 and CXCL12 were present in both patients with tuberculosis and in a sub-group participant with latent tuberculosis infection who showed a higher level of IFN-γ producing cells by ELISPOT assay compared with other latently infected individuals. (2 IL-6 and IL-9 were only significantly increased in plasma from active TB patients, and the two factors were consistently highly secreted after M.tb antigen stimulation. (3 When patients developed tuberculous pleurisy, CCL1, CCL21 and IL-6 were specifically increased in the pleural effusions. In particular, these three factors were consistently highly secreted by pleural fluid mononuclear cells following M

  1. Fifty years of eutrophication and lake restoration reflected in sedimentary carbon and nitrogen isotopes of a small, hardwater lake (south Germany

    Directory of Open Access Journals (Sweden)

    Emanuel Braig

    2013-04-01

    Full Text Available This study analyses the response of the carbon and nitrogen isotopic composition of sedimentary organic matter to rapid human-induced eutrophication and meromixis as well as subsequent restoration efforts [in-lake phosphorus (P-Precipitation, P-remediation of the well inflow and multiannual destratification] in a 46-yr sediment core sequence (1963-2009 from Fischkaltersee, a small hard-water lake (S-Germany. In addition, the sediment record was compared with detailed data on water column chemistry during almost (1977-2009 the recorded history of eutrophication and trophic recovery of the named lake. While the onset of eutrophication resulted in an abrupt positive excursion (+2.4‰, the overall reaction of δ13CSOM to ongoing eutrophication and meromixis as well as to permanent hypolimnion aeration and trophic recovery is a continous negative trend (-3.7‰ with the most depleted signatures (-38.8‰ present in the youngest part of the core. This negative trend was not influenced by multiannual hypolimnion aeration, which although oxygenating bottom waters (>2 mg O2 L–1, did not reverse the increasing anoxis in the sediment, as is indicated by an declining Mn/Fe ratio. Hence, we conclude that in Fischkaltersee δ13CSOM was controlled by photoautotrophic input only during an early phase in the eutrophication process. The signal of intensifying microbially mediated carbon cycling processes in the sediment, i.e. methanogenesis and methanotrophy, was superimposed on the primary productivity signal by crossing a certain TP threshold (approx. TP=0.04 mg L–1. Sedimentary δ15N values exhibit an overall increase (+3.4‰ in reaction to the eutrophication process, while trophic recovery produces a continous decrease in the signal (-2.7‰. Linear correlation of δ15N to nitrate utilisation in the epilimnion, however, is rather weak (R2=0.33. Comparison between sediment δ15N values and water column data reveals that two negative shifts in the

  2. Reflecting reflection in supervision

    DEFF Research Database (Denmark)

    Lystbæk, Christian Tang

    associated with reflection and an exploration of alternative conceptions that view reflection within the context of settings which have a more group- and team-based orientation. Drawing on an action research project on health care supervision, the paper questions whether we should reject earlier views...... of reflection, rehabilitate them in order to capture broader connotations or move to new ways of regarding reflection that are more in keeping with not only reflective but also emotive, normative and formative views on supervision. The paper presents a critical perspective on supervision that challenge...... the current reflective paradigm I supervision and relate this to emotive, normative and formative views supervision. The paper is relevant for Nordic educational research into the supervision and guidance...

  3. Spatial patterns of atmospheric deposition of nitrogen and sulfur using ion-exchange resin collectors in Rocky Mountain National Park, USA

    Science.gov (United States)

    Clow, David W.; Roop, Heidi; Nanus, Leora; Fenn, Mark; Sexstone, Graham A.

    2015-01-01

    Lakes and streams in Class 1 wilderness areas in the western United States (U.S.) are at risk from atmospheric deposition of nitrogen (N) and sulfur (S), and protection of these resources is mandated under the Federal Clean Air Act and amendments. Assessment of critical loads, which are the maximum exposure to pollution an area can receive without adverse effects on sensitive ecosystems, requires accurate deposition estimates. However, deposition is difficult and expensive to measure in high-elevation wilderness, and spatial patterns in N and S deposition in these areas remain poorly quantified. In this study, ion-exchange resin (IER) collectors were used to measure dissolved inorganic N (DIN) and S deposition during June 2006–September 2007 at approximately 20 alpine/subalpine sites spanning the Continental Divide in Rocky Mountain National Park. Results indicated good agreement between deposition estimated from IER collectors and commonly used wet + dry methods during summer, but poor agreement during winter. Snowpack sampling was found to be a more accurate way of quantifying DIN and S deposition during winter. Summer DIN deposition was significantly greater on the east side of the park than on the west side (25–50%; p ≤ 0.03), consistent with transport of pollutants to the park from urban and agricultural areas to the east. Sources of atmospheric nitrate (NO3−) were examined using N isotopes. The average δ15N of NO3− from IER collectors was 3.5‰ higher during winter than during summer (p model critical loads by filling gaps in geographic coverage of deposition monitoring/modeling programs and thus may enable policy makers to better protect sensitive natural resources in Class 1 Wilderness areas.

  4. Effects of Sowing Date, Planting Pattern and Nitrogen Levels on Leaf and Flower Essential Oil, Yield and Component Yield Grain of Buckwheat (Fagopyroum esculentum Moench

    Directory of Open Access Journals (Sweden)

    M. R Sobhani

    2017-12-01

    Full Text Available Introduction Buckwheat which has been scientifically named Fagopyrum esculentum can be considered as a yearling broad-leaved plant belonging to the family of Polygonaceae which is known as false Cereal. Its seeds are in use as a nutritional and medicinal product that is due to the rutin content of them. As the population is rapidly increasing worldwide, a solution must be found to supply necessary food. What agriculture science is responsible for is to produce more products with better quality in order to meet this increasing population’s needs so that food poverty and starvation are more likely to be removed and keep food safety. Considering the fact that buckwheat is of a variety of medical, industrial and food applications and in our country and some other ones, it has not been seriously cultivated, this plant must be used as a new plant and it should be extensively applied in multiple planting systems (summer planting for commercial goals through producing seeds while its nutritional value is more than grain and it can be regarded as a rich source of high quality protein, amino acid necessary for lysine, high starch percent, minerals and vitamins for different applications involving cake flour, frumenty and soup and improving the optimal rate of rutin as a secondary metabolite having effective medical features concerning our country’s climatic conditions. Materials and Methods In order to investigate the effects of sowing date, planting patterns and nitrogen on leaf and flower rutin, yield and yield component of Buckwheat plant, a field study was conducted during 2010 and 2011 in Agricultural Research Institute of Arak, Iran. The experimental design was regarded as the randomized complete block design in the form of split plot factorial with three replications. Planting treatments as the fundamental elements may be implemented at two levels including the mounds with the width of 50 cm associated with two planting rows regarding the

  5. Decadal-scale export of nitrogen, phosphorus, and sediment from the Susquehanna River basin, USA: Analysis and synthesis of temporal and spatial patterns.

    Science.gov (United States)

    Zhang, Qian; Ball, William P; Moyer, Douglas L

    2016-09-01

    The export of nitrogen (N), phosphorus (P), and suspended sediment (SS) is a long-standing management concern for the Chesapeake Bay watershed, USA. Here we present a comprehensive evaluation of nutrient and sediment loads over the last three decades at multiple locations in the Susquehanna River basin (SRB), Chesapeake's largest tributary watershed. Sediment and nutrient riverine loadings, including both dissolved and particulate fractions, have generally declined at all sites upstream of Conowingo Dam (non-tidal SRB outlet). Period-of-record declines in riverine yield are generally smaller than those in source input, suggesting the possibility of legacy contributions. Consistent with other watershed studies, these results reinforce the importance of considering lag time between the implementation of management actions and achievement of river quality improvement. Whereas flow-normalized loadings for particulate species have increased recently below Conowingo Reservoir, those for upstream sites have declined, thus substantiating conclusions from prior studies about decreased reservoir trapping efficiency. In regard to streamflow effects, statistically significant log-linear relationships between annual streamflow and annual constituent load suggest the dominance of hydrological control on the inter-annual variability of constituent export. Concentration-discharge relationships revealed general chemostasis and mobilization effects for dissolved and particulate species, respectively, both suggesting transport-limitation conditions. In addition to affecting annual export rates, streamflow has also modulated the relative importance of dissolved and particulate fractions, as reflected by its negative correlations with dissolved P/total P, dissolved N/total N, particulate P/SS, and total N/total P ratios. For land-use effects, period-of-record median annual yields of N, P, and SS all correlate positively with the area fraction of non-forested land but negatively with

  6. Decadal-scale export of nitrogen, phosphorus, and sediment from the Susquehanna River basin, USA: Analysis and synthesis of temporal and spatial patterns

    Science.gov (United States)

    Zhang, Qian; Ball, William P.; Moyer, Douglas

    2016-01-01

    The export of nitrogen (N), phosphorus (P), and suspended sediment (SS) is a long-standing management concern for the Chesapeake Bay watershed, USA. Here we present a comprehensive evaluation of nutrient and sediment loads over the last three decades at multiple locations in the Susquehanna River basin (SRB), Chesapeake's largest tributary watershed. Sediment and nutrient riverine loadings, including both dissolved and particulate fractions, have generally declined at all sites upstream of Conowingo Dam (non-tidal SRB outlet). Period-of-record declines in riverine yield are generally smaller than those in source input, suggesting the possibility of legacy contributions. Consistent with other watershed studies, these results reinforce the importance of considering lag time between the implementation of management actions and achievement of river quality improvement. Whereas flow-normalized loadings for particulate species have increased recently below Conowingo Reservoir, those for upstream sites have declined, thus substantiating conclusions from prior studies about decreased reservoir trapping efficiency. In regard to streamflow effects, statistically significant log-linear relationships between annual streamflow and annual constituent load suggest the dominance of hydrological control on the inter-annual variability of constituent export. Concentration-discharge relationships revealed general chemostasis and mobilization effects for dissolved and particulate species, respectively, both suggesting transport-limitation conditions. In addition to affecting annual export rates, streamflow has also modulated the relative importance of dissolved and particulate fractions, as reflected by its negative correlations with dissolved P/total P, dissolved N/total N, particulate P/SS, and total N/total P ratios. For land-use effects, period-of-record median annual yields of N, P, and SS all correlate positively with the area fraction of non-forested land but negatively with

  7. Voluntary intake, nitrogen metabolism and rumen fermentation ...

    African Journals Online (AJOL)

    Voluntary intake, nitrogen metabolism and rumen fermentation patterns in sheep given cowpea, silverleaf desmodium and fine-stem stylo legume hays as ... utilisation, the negative nitrogen retentions might indicate the inadequacy of the specific legume hays used as nitrogen supplementary feeds to sheep fed a basal diet

  8. [Effects of reduced nitrogen application and soybean intercropping on nitrogen balance of sugarcane field].

    Science.gov (United States)

    Liu, Yu; Zhang, Ying; Yang, Wen-ting; Li, Zhi-xian; Guan, Ao-mei

    2015-03-01

    A four-year (2010-2013) field experiment was carried out to explore the effects of three planting patterns (sugarcane, soybean monoculture and sugarcane-soybean 1:2 intercropping) with two nitrogen input levels (300 and 525 kg . hm-2) on soybean nitrogen fixation, sugarcane and soybean nitrogen accumulation, and ammonia volatilization and nitrogen leaching in sugarcane field. The results showed that the soybean nitrogen fixation efficiency (NFE) of sugarcane-soybean inter-cropping was lower than that of soybean monoculture. There was no significant difference in NFE among the treatments with the two nitrogen application rates. The nitrogen application rate and inter-cropping did not remarkably affect nitrogen accumulation of sugarcane and soybean. The ammonia volatilization of the reduced nitrogen input treatment was significantly lower than that of the conventional nitrogen input treatment. Furthermore, there was no significant difference in nitrogen leaching at different nitrogen input levels and among different planting patterns. The sugarcane field nitrogen balance analysis indicated that the nitrogen application rate dominated the nitrogen budget of sugarcane field. During the four-year experiment, all treatments leaved a nitrogen surplus (from 73.10 to 400.03 kg . hm-2) , except a nitrogen deficit of 66.22 kg . hm-2 in 2011 in the treatment of sugarcane monoculture with the reduced nitrogen application. The excessive nitrogen surplus might increase the risk of nitrogen pollution in the field. In conclusion, sugarcane-soybean intercropping with reduced nitrogen application is feasible to practice in consideration of enriching the soil fertility, reducing nitrogen pollution and saving production cost in sugarcane field.

  9. Present spatial diversity patterns of Theobroma cacao L. in the neotropics reflect genetic differentiation in pleistocene refugia followed by human-influenced dispersal.

    Science.gov (United States)

    Thomas, Evert; van Zonneveld, Maarten; Loo, Judy; Hodgkin, Toby; Galluzzi, Gea; van Etten, Jacob

    2012-01-01

    Cacao (Theobroma cacao L.) is indigenous to the Amazon basin, but is generally believed to have been domesticated in Mesoamerica for the production of chocolate beverage. However, cacao's distribution of genetic diversity in South America is also likely to reflect pre-Columbian human influences that were superimposed on natural processes of genetic differentiation. Here we present the results of a spatial analysis of the intra-specific diversity of cacao in Latin America, drawing on a dataset of 939 cacao trees genotypically characterized by means of 96 SSR markers. To assess continental diversity patterns we performed grid-based calculations of allelic richness, Shannon diversity and Nei gene diversity, and distinguished different spatially coherent genetic groups by means of cluster analysis. The highest levels of genetic diversity were observed in the Upper Amazon areas from southern Peru to the Ecuadorian Amazon and the border areas between Colombia, Peru and Brazil. On the assumption that the last glaciation (22,000-13,000 BP) had the greatest pre-human impact on the current distribution and diversity of cacao, we modeled the species' Pleistocene niche suitability and overlaid this with present-day diversity maps. The results suggest that cacao was already widely distributed in the Western Amazon before the onset of glaciation. During glaciations, cacao populations were likely to have been restricted to several refugia where they probably underwent genetic differentiation, resulting in a number of genetic clusters which are representative for, or closest related to, the original wild cacao populations. The analyses also suggested that genetic differentiation and geographical distribution of a number of other clusters seem to have been significantly affected by processes of human management and accompanying genetic bottlenecks. We discuss the implications of these results for future germplasm collection and in situ, on farm and ex situ conservation of cacao.

  10. Patterns of cross-sensitivity in the responses of clonal subpopulations isolated from the RIF-1 mouse sarcoma to selected nitrosoureas and nitrogen mustards.

    OpenAIRE

    Reeve, J. G.; Wright, K. A.; Workman, P.

    1984-01-01

    The response of clonal subpopulations isolated from the RIF-1 mouse sarcoma to melphalan treatment is independent of cell ploidy, whereas a clear relationship exists between ploidy and cell sensitivity to CCNU treatment. In the present study RIF-1 clones have been exposed to nitrogen mustard, aniline mustard and chlorambucil, and to nitrosoureas BCNU, MeCCNU and chlorozotocin, in order to evaluate whether or not the different physiochemical and biological activities of these agents would affe...

  11. Isotope Investigations of Nitrogen Compounds in Different Aquatic Ecosystems in Cyprus, Russia and Ukraine

    Energy Technology Data Exchange (ETDEWEB)

    Voropaev, A.; Voerkelius, S.; Eichinger, L. [Hydroisotop GmbH, Schweitenkirchen (Germany); Grinenko, V. [Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, Moscow (Russian Federation)

    2013-07-15

    The isotope analyses of nitrogen compounds is a powerful tool for the investigation of anrthropogenic influence on the nitrogen cycle in terrestrial and aquatic ecosystems. The isotopic composition of nitrogen and oxygen in nitrates from different groundwater aquifers in Cyprus reflects anthropogenic inputs of nitrogen mainly from industrial fertilizer application in agriculture. Significant denitrification as identified at many sampling sites is an important process, which reduces nitrate concentrations in groundwater. In surface water ecosystems anthropogenic influences and natural environmental changes are detected by the isotopic composition of nitrogen in suspended organic material and in bottom sediments. In the oligotrophic fresh water of Lake Galich in Russia the waste water outflow is a reason for the local increase of {delta}{sup 15}N values in bottom sediments, where the nitrogen and carbon isotopic compositions of unpolluted sediments are very homogeneous. In the Neva estuary in russia the lateral destribution of {delta}{sup 15}N values in upper layers of bottom sediments reflects changes in the mixing pattern of marine and continental organic matter caused by a flood protection dam building in the Dneprovsko-Bugsky estuary in Ukraine - probably the increasing influence of anthropogenic {sup 15}N enriched nutrient load. (author)

  12. The Reflective Learning Continuum: Reflecting on Reflection

    Science.gov (United States)

    Peltier, James W.; Hay, Amanda; Drago, William

    2005-01-01

    The importance of reflection to marketing educators is increasingly recognized. However, there is a lack of empirical research that considers reflection within the context of both the marketing and general business education literature. This article describes the use of an instrument that can be used to measure four identified levels of a…

  13. Nitrogen regulation of the xyl genes of Pseudomonas putida mt-2 propagates into a significant effect of nitrate on m-xylene mineralization in soil

    DEFF Research Database (Denmark)

    Svenningsen, Nanna Bygvraa; Nicolaisen, Mette Haubjerg; Hansen, Hans Chr. Bruun

    2016-01-01

    nitrogen sensing status in both experimental systems. Hence, for nitrogen sources, regulatory patterns that emerge in soil reflect those observed in liquid cultures. The current study shows how distinct regulatory traits can lead to discrete environmental consequences; and it underpins that attempts......The nitrogen species available in the growth medium are key factors determining expression of xyl genes for biodegradation of aromatic compounds by Pseudomonas putida. Nitrogen compounds are frequently amended to promote degradation at polluted sites, but it remains unknown how regulation observed...... that NO3(-) compared with NH4(+) had a stimulating effect on xyl gene expression in pure culture as well as in soil, and that this stimulation was translated into increased m-xylene mineralization in soil. Furthermore, expression analysis of the nitrogen-regulated genes amtB and gdhA allowed us to monitor...

  14. Reflective photovoltaics

    Energy Technology Data Exchange (ETDEWEB)

    Lentine, Anthony L.; Nielson, Gregory N.; Cruz-Campa, Jose Luis; Okandan, Murat; Goeke, Ronald S.

    2018-03-06

    A photovoltaic module includes colorized reflective photovoltaic cells that act as pixels. The colorized reflective photovoltaic cells are arranged so that reflections from the photovoltaic cells or pixels visually combine into an image on the photovoltaic module. The colorized photovoltaic cell or pixel is composed of a set of 100 to 256 base color sub-pixel reflective segments or sub-pixels. The color of each pixel is determined by the combination of base color sub-pixels forming the pixel. As a result, each pixel can have a wide variety of colors using a set of base colors, which are created, from sub-pixel reflective segments having standard film thicknesses.

  15. Registered Trademarks… Reflections on the use of trademarks, consumption patterns and marketing strategies in rural areas of Argentina (1900-1930

    Directory of Open Access Journals (Sweden)

    Andrea Lluch

    2013-06-01

    Full Text Available Trademarks are highly valuable devices that serve a relevant purpose in trade and consumption patterns. However, trademarks have been largely neglected by Argentina's economic history historiography. This article discusses how and when trademarks emerged and spread in Argentina's rural area in the early 20th century. It describes this gradual process, pointing out that, by the late 1920s, trademarks had already become a prominent feature in rural marketing strategies and consumption patterns. The study also analyzes how these processes contributed to shaping retailers' business practices as well as generic consumer goods' marketing channels (particularly, in the food and beverage industries

  16. Patterns of change in the size spectra of numbers and diversity of the North Sea fish assemblage, as reflected in surveys and models

    DEFF Research Database (Denmark)

    Rice, J.; Gislason, Henrik

    1996-01-01

    data. The shape showed no overall trend, but diversity of smaller size classes showed a different temporal pattern from the diversity of intermediate and large size classes. The patterns in modelled output are consistent with, but do not prove, the hypothesis that trophic interactions are an important...... were very similar. Annual abundance spectra were linear and slopes increased significantly and fairly smoothly over the 20 years? indicating significant effects of fishing on the size composition of the exploited fish assemblage. The annual diversity spectra were more dome-shaped than in the survey...... factor in the fish community structure in the North Sea. (C) 1996 International Council for the Exploration of the Sea....

  17. Nitrogen tank

    CERN Multimedia

    2006-01-01

    Wanted The technical file about the pressure vessel RP-270 It concerns the Nitrogen tank, 60m3, 22 bars, built in 1979, and installed at Point-2 for the former L3 experiment. If you are in possession of this file, or have any files about an equivalent tank (probably between registered No. RP-260 and -272), please contact Marc Tavlet, the ALICE Glimos.

  18. Inverse isolation of dissolved inorganic nitrogen yield for individual land-uses from mosaic land-use patterns within a watershed

    Science.gov (United States)

    Shih, Y.-T.; Lee, T.-Y.; Huang, J.-C.; Kao, S.-J.; Liu, K.-K.; Chang, F.-J.

    2015-01-01

    This study combines the observed riverine DIN (dissolved inorganic nitrogen) export and the controlling factors (land-use, population and discharge) to inversely estimate the effective DIN yield factors for individual land-use and DIN per capita loading. A total of 16 sub-catchments, with different land-use compositions on the Danshui River of Taiwan, were used in this study. Observed riverine DIN concentrations and yields varied from 20-450 μM and 400-10 000 kg N km-2 yr-1 corresponding to the increase of urbanization gradient (e.g. building and population). Meanwhile, the transport behaviors changed from hydrological enhancement to dilution with increasing urbanization as well. Our method shows that the DIN yield factors, independent of discharge, are 12.7, 63.9, and 1381.0 μM, for forest, agriculture, and building, respectively, which equals to 444.5, 2236.5, 48 335 kg N km-2 yr-1 at the given annual runoff of 2500 mm. The agriculture DIN yield only accounts for 10% of fertilizer application indicating the complicated N cascade and possible over fertilization. The DIN per capita loading (~0.49 kg N capita-1 yr-1) which is lower than the documented human N emission (1.6-5.5 kg N capita-1 yr-1) can be regarded as an effective export coefficient after treatment or retention. A conducted scenario experiment supports the observations demonstrating the capability for assessment. We therefore, can extrapolate all possible combinations of land-use, discharge, and population density for evaluation. This can provide a strong basis for watershed management and supplementary estimation for regional to global study.

  19. Crystalline amino acids and nitrogen emission

    NARCIS (Netherlands)

    Verstegen, M.W.A.; Jongbloed, A.W.

    2003-01-01

    Reductions in dietary protein level and supplementation with certain crystalline amino acids is a well-established method of formulating diets to achieve a more ideal amino acid pattern and to reduce nitrogen excretion. Up to 35% reduction in nitrogen excretion may be achieved by supplementing pig

  20. Personal Reflections

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education. Personal Reflections. Articles in Resonance – Journal of Science Education. Volume 6 Issue 3 March 2001 pp 90-93 Personal Reflections. Why did I opt for Career in Science? Jayant V Narlikar · More Details Fulltext PDF. Volume 9 Issue 8 August 2004 pp 89-89 ...

  1. Reflection groups

    International Nuclear Information System (INIS)

    Eggermont, G.

    2006-01-01

    In 2005, PISA organised proactive meetings of reflection groups on involvement in decision making, expert culture and ethical aspects of radiation protection.All reflection group meetings address particular targeted audiences while the output publication in book form is put forward

  2. Reflection ciphers

    DEFF Research Database (Denmark)

    Boura, Christina; Canteaut, Anne; Knudsen, Lars Ramkilde

    2017-01-01

    study the necessary properties for this coupling permutation. Special care has to be taken of some related-key distinguishers since, in the context of reflection ciphers, they may provide attacks in the single-key setting.We then derive some criteria for constructing secure reflection ciphers...

  3. Quantifying Reflection

    DEFF Research Database (Denmark)

    Alcock, Gordon Lindsay

    2013-01-01

    ´ These are all based on Blooms taxonomy and levels of competence and form a major part of individual student and group learning portfolios. Key Words :Project-Based learning, Reflective Portfolios, Self assessment, Defining learning gains, Developing learning strategies , Reflections on and for learning....... It contrasts the students’ self-assessment in a range of ‘product’ skills such as Revit, Structural Design, Mathematics of construction, Technical Installations; as well as ‘process’ competencies such as ‘Working in a team’, Sharing knowledge, Maintaining a portfolio and Reflecting ON learning and FOR learning......This paper documents 1st semester student reflections on “learning to learn” in a team-based PBL environment with quantitative and qualitative student reflective feedback on the learning gains of 60 Architectural Technology and Construction Management students at VIA University College, Denmark...

  4. Variation in foliar nitrogen and albedo in response to nitrogen fertilization and elevated CO2

    Science.gov (United States)

    Haley F. Wicklein; Scott V. Ollinger; Mary E. Martin; David Y. Hollinger; Lucie C. Lepine; Michelle C. Day; Megan K. Bartlett; Andrew D. Richardson; Richard J. Norby

    2012-01-01

    Foliar nitrogen has been shown to be positively correlated with midsummer canopy albedo and canopy near infrared (NIR) reflectance over a broad range of plant functional types (e.g., forests, grasslands, and agricultural lands). To date, the mechanism(s) driving the nitrogen-albedo relationship have not been established, and it is unknown whether factors affecting...

  5. Virtual Nitrogen Losses from Organic Food Production

    Science.gov (United States)

    Cattell Noll, L.; Galloway, J. N.; Leach, A. M.; Seufert, V.; Atwell, B.; Shade, J.

    2015-12-01

    Reactive nitrogen (Nr) is necessary for crop and animal production, but when it is lost to the environment, it creates a cascade of detrimental environmental impacts. The nitrogen challenge is to maximize the food production benefits of Nr, while minimizing losses to the environment. The first nitrogen footprint tool was created in 2012 to help consumers learn about the Nr losses to the environment that result from an individual's lifestyle choices. The nitrogen lost during food production was estimated with virtual nitrogen factors (VNFs) that quantify the amount of nitrogen lost to the environment per unit nitrogen consumed. Alternative agricultural systems, such as USDA certified organic farms, utilize practices that diverge from conventional production. In order to evaluate the potential sustainability of these alternative agricultural systems, our team calculated VNFs that reflect organic production. Initial data indicate that VNFs for organic grains and organic starchy roots are comparable to, but slightly higher than conventional (+10% and +20% respectively). In contrast, the VNF for organic vegetables is significantly higher (+90%) and the VNF for organic legumes is significantly lower (-90%). Initial data on organic meat production shows that organic poultry and organic pigmeat are comparable to conventional production (both <5% difference), but that the organic beef VNF is significantly higher (+30%). These data show that in some cases organic and conventional production are comparable in terms of nitrogen efficiency. However, since conventional production relies heavily on the creation of new reactive nitrogen (Haber-Bosch, biological nitrogen fixation) and organic production primarily utilizes already existing reactive nitrogen (manure, crop residue, compost), the data also show that organic production contributes less new reactive nitrogen to the environment than conventional production (approximately 70% less). Therefore, we conclude that on a local

  6. Carbon source utilization patterns of Bacillus simplex ecotypes do not reflect their adaptation to ecologically divergent slopes in 'Evolution Canyon', Israel.

    Science.gov (United States)

    Sikorski, Johannes; Pukall, Rüdiger; Stackebrandt, Erko

    2008-10-01

    The 'Evolution Canyons' I and II in Israel are model habitats to study adaptation and speciation of bacteria in the environment. These canyons represent similar ecological replicates, separated by 40 km, with a strongly sun-exposed and hot 'African' south-facing slope (SFS) vs. a cooler and mesic-lush 'European' north-facing slope (NFS). Previously, among 131 Bacillus simplex isolates, distinct genetic lineages (ecotypes), each specific for either SFS or NFS, were identified, suggesting a temperature-driven slope-specific adaptation. Here, we asked whether the ecological heterogeneity of SFS vs. NFS also affected carbon utilization abilities, as determined using the Biolog assay. Contrary to expectation, a correlation between substrate utilization patterns and the ecological origin of strains was not found. Rather, the patterns split according to the two major phylogenetic lineages each of which contain SFS and NFS ecotypes. We conclude that traits related to the general energy metabolism, as far as assessed here, are neither shaped by the major abiotic features of 'Evolution Canyon', namely solar radiation, temperature, and drought, nor by the soil characteristics. We further conclude that some traits diverge rather neutrally from each other, whereas other, more environmentally related traits are shaped by natural selection and show evolutionary convergence.

  7. Selectively reflective transparent sheets

    Science.gov (United States)

    Waché, Rémi; Florescu, Marian; Sweeney, Stephen J.; Clowes, Steven K.

    2015-08-01

    We investigate the possibility to selectively reflect certain wavelengths while maintaining the optical properties on other spectral ranges. This is of particular interest for transparent materials, which for specific applications may require high reflectivity at pre-determined frequencies. Although there exist currently techniques such as coatings to produce selective reflection, this work focuses on new approaches for mass production of polyethylene sheets which incorporate either additives or surface patterning for selective reflection between 8 to 13 μ m. Typical additives used to produce a greenhouse effect in plastics include particles such as clays, silica or hydroxide materials. However, the absorption of thermal radiation is less efficient than the decrease of emissivity as it can be compared with the inclusion of Lambertian materials. Photonic band gap engineering by the periodic structuring of metamaterials is known in nature for producing the vivid bright colors in certain organisms via strong wavelength-selective reflection. Research to artificially engineer such structures has mainly focused on wavelengths in the visible and near infrared. However few studies to date have been carried out to investigate the properties of metastructures in the mid infrared range even though the patterning of microstructure is easier to achieve. We present preliminary results on the diffuse reflectivity using FDTD simulations and analyze the technical feasibility of these approaches.

  8. Immunohistochemical study of Ulex europaeus agglutinin 1 (UEA-1) binding of megakaryocytes in bone marrow biopsy specimens: demonstration of heterogeneity in staining pattern reflecting the stages of differentiation.

    Science.gov (United States)

    Liu, S M; Li, C Y

    1996-01-01

    During differentiation, megakaryocytes undergo nuclear endoreplication, an increase in cell size, cytoplasmic granulation, and release of platelets. The changes in highly lobulated nuclei with varying degree of polyploidy and increasing cell size are easily recognized morphologically. However, the actual cytoplasmic changes are more difficult to perceive morphologically. With the peroxidase-antiperoxidase (PAP) method using UEA-1 as the binding protein to the alpha-L-fucose of glycoprotein synthesized by megakaryocytes, we observed significant variation in cytoplasmic staining of megakaryocytes in routinely processed bone marrow biopsy sections. A total of 3344 megakaryocytes in bone marrow sections from 10 patients with nonhematologic diseases and from 10 patients with idiopathic thrombocytopenic purpura (ITP) was studied. According to the intensity and pattern of cytoplasmic staining, we divided megakaryocytes into at least six groups: (1) low granular (LG), (2) diffuse granular (DG), (3) diffuse dense granular (DDG), (4) marginal granular (MG), (5) denuded (DMK), and (6) endomitotic (EndoM). Most of the megakaryocytes were DG (mean, 42.75% +/- 19.21%) and DDG (mean, 50.25% +/- 21.23%). In correlation with nuclear morphology and cell size, it appears that substances binding to UEA-1 are located in the paranuclear region in early megakaryocytes and produce a low granular focal staining pattern (LG cells). Next, the granules spread throughout the cytoplasm (DG cells) and increase in quantity (DDG). This is followed by migration of granules to the periphery of the cytoplasm (MG cells) and is associated with the liberation of platelets and eventual formation of DMK megakaryocytes. Endomitosis, regulated by unknown factors, occurred in the MG stage. In comparing the group with nonhematologic disease (mean DG, 35.4% +/- 18.48%; DDG, 58.4% +/- 21.8%) and the group with ITP (mean DG, 50.1% +/- 17.82%; DDG, 42.1% +/- 18.12%), we found an increasing proportion of DG

  9. CyberLondon: A Virtual City for the Posthuman? Literary Reflections on the Changing Patterns of our Relationship with the Metropolis in the Information Era.

    Directory of Open Access Journals (Sweden)

    Maria Goicoechea de Joerge

    2010-08-01

    Full Text Available http://dx.doi.org/10.5007/1807-9288.2009v5n2p188 This paper explores the changing patterns of our relationship with the metropolis from the perspective of London-based writers that have shown an interest for cyberculture (Matt Whyman, Stella Duffy, Pat Cadigan, China Miéville. Taking as point of departure the collection of Internet stories edited by Maxim Jakubowski with authors from a variety of fields, including crime, mystery, science-fiction, fantasy, and even erotica, this paper will analyze how popular literature has understood the role of the city of London and its social networks in the new informational society. The theoretical approach used to read these short stories is indebted to the ideas of urban theorist and sociologist Manuel Castells and cyberculture theorist Donna Haraway.

  10. Patterns of variation at Ustilago maydis virulence clusters 2A and 19A largely reflect the demographic history of its populations.

    Directory of Open Access Journals (Sweden)

    Ronny Kellner

    Full Text Available The maintenance of an intimate interaction between plant-biotrophic fungi and their hosts over evolutionary times involves strong selection and adaptative evolution of virulence-related genes. The highly specialised maize pathogen Ustilago maydis is assigned with a high evolutionary capability to overcome host resistances due to its high rates of sexual recombination, large population sizes and long distance dispersal. Unlike most studied fungus-plant interactions, the U. maydis - Zea mays pathosystem lacks a typical gene-for-gene interaction. It exerts a large set of secreted fungal virulence factors that are mostly organised in gene clusters. Their contribution to virulence has been experimentally demonstrated but their genetic diversity within U. maydis remains poorly understood. Here, we report on the intraspecific diversity of 34 potential virulence factor genes of U. maydis. We analysed their sequence polymorphisms in 17 isolates of U. maydis from Europe, North and Latin America. We focused on gene cluster 2A, associated with virulence attenuation, cluster 19A that is crucial for virulence, and the cluster-independent effector gene pep1. Although higher compared to four house-keeping genes, the overall levels of intraspecific genetic variation of virulence clusters 2A and 19A, and pep1 are remarkably low and commensurate to the levels of 14 studied non-virulence genes. In addition, each gene is present in all studied isolates and synteny in cluster 2A is conserved. Furthermore, 7 out of 34 virulence genes contain either no polymorphisms or only synonymous substitutions among all isolates. However, genetic variation of clusters 2A and 19A each resolve the large scale population structure of U. maydis indicating subpopulations with decreased gene flow. Hence, the genetic diversity of these virulence-related genes largely reflect the demographic history of U. maydis populations.

  11. Tightening the nitrogen cycle

    OpenAIRE

    Christensen, B.T.

    2004-01-01

    The availability of nitrogen to crop plants is a universally important aspect of soil quality, and often nitrogen represents the immediate limitation to crop productivity in modern agriculture. Nitrogen is decisive for the nutritive value of plant products and plays a key role in the environmental impact of agricultural production. The fundamental doctrine of nitrogen management is to optimise the nitrogen use efficiency of both introduced and native soil nitrogen by increasing the temporal a...

  12. TRANSCRIPTOME ANALYSES REVEAL DIFFERENTIAL GENE EXPRESSION PATTERNS BETWEEN THE LIFE-CYCLE STAGES OF EMILIANIA HUXLEYI (HAPTOPHYTA) AND REFLECT SPECIALIZATION TO DIFFERENT ECOLOGICAL NICHES(1).

    Science.gov (United States)

    Rokitta, Sebastian D; de Nooijer, Lennart J; Trimborn, Scarlett; de Vargas, Colomban; Rost, Björn; John, Uwe

    2011-08-01

    Coccolithophores, especially the abundant, cosmopolitan species Emiliania huxleyi (Lohmann) W. W. Hay et H. P. Mohler, are one of the main driving forces of the oceanic carbonate pump and contribute significantly to global carbon cycling, due to their ability to calcify. A recent study indicates that termination of diploid blooms by viral infection induces life-cycle transition, and speculation has arisen about the role of the haploid, noncalcifying stage in coccolithophore ecology. To explore gene expression patterns in both life-cycle stages, haploid and diploid cells of E. huxleyi (RCC 1217 and RCC 1216) were acclimated to limiting and saturating photon flux densities. Transcriptome analyses were performed to assess differential genomic expression related to different ploidy levels and acclimation light intensities. Analyses indicated that life-cycle stages exhibit different properties of regulating genome expression (e.g., pronounced gene activation and gene silencing in the diploid stage), proteome maintenance (e.g., increased turnover of proteins in the haploid stage), as well as metabolic processing (e.g., pronounced primary metabolism and motility in the haploid stage and calcification in the diploid stage). Furthermore, higher abundances of transcripts related to endocytotic and digestive machinery were observed in the diploid stage. A qualitative feeding experiment indicated that both life-cycle stages are capable of particle uptake (0.5 μm diameter) in late-stationary growth phase. Results showed that the two life-cycle stages represent functionally distinct entities that are evolutionarily shaped to thrive in the environment they typically inhabit. © 2011 Phycological Society of America.

  13. Different temperature and cooling patterns at the blunt and sharp egg poles reflect the arrangement of eggs in an avian clutch.

    Science.gov (United States)

    Šálek, Miroslav E; Zárybnická, Markéta

    2015-01-01

    Incubation is an energetically demanding process during which birds apply heat to their eggs to ensure embryonic development. Parent behaviours such as egg turning and exchanging the outer and central eggs in the nest cup affect the amount of heat lost to the environment from individual eggs. Little is known, however, about whether and how egg surface temperature and cooling rates vary among the different areas of an egg and how the arrangement of eggs within the clutch influences heat loss. We performed laboratory (using Japanese quail eggs) and field (with northern lapwing eggs) experiments using infrared imaging to assess the temperature and cooling patterns of heated eggs and clutches. We found that (i) the sharp poles of individual quail eggs warmed to a higher egg surface temperature than did the blunt poles, resulting in faster cooling at the sharp poles compared to the blunt poles; (ii) both quail and lapwing clutches with the sharp poles oriented towards the clutch centre (arranged clutches) maintained higher temperatures over the central part of the clutch than occurred in those clutches where most of the sharp egg poles were oriented towards the exterior (scattered clutches); and (iii) the arranged clutches of both quail and lapwing showed slower cooling rates at both the inner and outer clutch positions than did the respective parts of scattered clutches. Our results demonstrate that egg surface temperature and cooling rates differ between the sharp and blunt poles of the egg and that the orientation of individual eggs within the nest cup can significantly affect cooling of the clutch as a whole. We suggest that birds can arrange their eggs within the nest cup to optimise thermoregulation of the clutch.

  14. Toward a Mechanistic Modeling of Nitrogen Limitation on Vegetation Dynamics

    OpenAIRE

    Xu, Chonggang; Fisher, Rosie; Wullschleger, Stan D.; Wilson, Cathy J.; Cai, Michael; McDowell, Nate G.

    2012-01-01

    Nitrogen is a dominant regulator of vegetation dynamics, net primary production, and terrestrial carbon cycles; however, most ecosystem models use a rather simplistic relationship between leaf nitrogen content and photosynthetic capacity. Such an approach does not consider how patterns of nitrogen allocation may change with differences in light intensity, growing-season temperature and CO(2) concentration. To account for this known variability in nitrogen-photosynthesis relationships, we deve...

  15. Reflectance Modeling

    Science.gov (United States)

    Smith, J. A.; Cooper, K.; Randolph, M.

    1984-01-01

    A classical description of the one dimensional radiative transfer treatment of vegetation canopies was completed and the results were tested against measured prairie (blue grama) and agricultural canopies (soybean). Phase functions are calculated in terms of directly measurable biophysical characteristics of the canopy medium. While the phase functions tend to exhibit backscattering anisotropy, their exact behavior is somewhat more complex and wavelength dependent. A Monte Carlo model was developed that treats soil surfaces with large periodic variations in three dimensions. A photon-ray tracing technology is used. Currently, the rough soil surface is described by analytic functions and appropriate geometric calculations performed. A bidirectional reflectance distribution function is calculated and, hence, available for other atmospheric or canopy reflectance models as a lower boundary condition. This technique is used together with an adding model to calculate several cases where Lambertian leaves possessing anisotropic leaf angle distributions yield non-Lambertian reflectance; similar behavior is exhibited for simulated soil surfaces.

  16. Reflective optics

    CERN Document Server

    Korsch, Dietrich

    1991-01-01

    This is the first book dedicated exclusively to all-reflective imaging systems. It is a teaching tool as well as a practical design tool for anyone who specializes in optics, particularly for those interested in telescopes, infrared, and grazing-incidence systems. The first part of the book describes a unified geometric optical theory of all-reflective imaging systems (from near-normal to grazing incidence) developed from basic principles. The second part discusses correction methods and a multitude of closed-form solutions of well-corrected systems, supplemented with many conventional and unc

  17. A tradeoff frontier for global nitrogen use and cereal production

    International Nuclear Information System (INIS)

    Mueller, Nathaniel D; West, Paul C; Gerber, James S; MacDonald, Graham K; Foley, Jonathan A; Polasky, Stephen

    2014-01-01

    Nitrogen fertilizer use across the world’s croplands enables high-yielding agricultural production, but does so at considerable environmental cost. Imbalances between nitrogen applied and nitrogen used by crops contributes to excess nitrogen in the environment, with negative consequences for water quality, air quality, and climate change. Here we utilize crop input-yield models to investigate how to minimize nitrogen application while achieving crop production targets. We construct a tradeoff frontier that estimates the minimum nitrogen fertilizer needed to produce a range of maize, wheat, and rice production levels. Additionally, we explore potential environmental consequences by calculating excess nitrogen along the frontier using a soil surface nitrogen balance model. We find considerable opportunity to achieve greater production and decrease both nitrogen application and post-harvest excess nitrogen. Our results suggest that current (circa 2000) levels of cereal production could be achieved with ∼50% less nitrogen application and ∼60% less excess nitrogen. If current global nitrogen application were held constant but spatially redistributed, production could increase ∼30%. If current excess nitrogen were held constant, production could increase ∼40%. Efficient spatial patterns of nitrogen use on the frontier involve substantial reductions in many high-use areas and moderate increases in many low-use areas. Such changes may be difficult to achieve in practice due to infrastructure, economic, or political constraints. Increases in agronomic efficiency would expand the frontier to allow greater production and environmental gains

  18. Large variations in diurnal and seasonal patterns of sap flux among Aleppo pine trees in semi-arid forest reflect tree-scale hydraulic adjustments

    Science.gov (United States)

    Preisler, Yakir; Tatarinov, Fyodor; Rohatyn, Shani; Rotenberg, Eyal; Grünzweig, José M.; Klein, Tamir; Yakir, Dan

    2015-04-01

    Adjustments and adaptations of trees to drought vary across different biomes, species and habitats, with important implications for tree mortality and forest dieback associated with global climate change. The aim of this study was to investigate possible links between the patterns of variations in water flux dynamics and drought resistance in Aleppo pine (Pinus halepensis) trees in a semi-arid stand (Yatir forest, Israel). We measured sap flow (SF) and variations in stem diameter, complemented with short-term campaigns of leaf-scale measurements of water vapour and CO2 gas exchange, branch water potential and hydraulic conductivity, as well as eddy flux measurements of evapotranspiration (ET) from a permanent flux tower at the site. SF rates were well synchronized with ET, reaching maximum rates during midday in all trees during the rainy season (Dec-Apr). However, during the dry season (May-Nov), the daily trend in the rates of SF greatly varied among trees, allowing classification into three tree classes: 1) trees with SF maximum rate constantly occurring in mid-day (12:00-13:00); 2)trees showing a shift to an early morning SF peak (04:00-06:00); and 3) trees shifting their daily SF peak to the evening (16:00-18:00). This classification did not change during the four years study period, between 2010 and 2014. Checking for correlation of tree parameters as DBH, tree height, crown size, and competition indices with rates of SF, indicated that timing of maximum SF in summer was mainly related to tree size (DBH), when large trees tended to have a later SF maximum. Dendrometer measurements indicated that large trees (high DBH) had maximum daily diameter in the morning during summer and winter, while small trees typically had maximum daily diameter during midday and afternoon in winter and summer, respectively. Leaf-scale transpiration (T) measurements showed typical morning peak in all trees, and another peak in the afternoon in large trees only. Different diurnal

  19. Nitrogen speciation and trends, and prediction of denitrification extent, in shallow US groundwater

    Science.gov (United States)

    Hinkle, Stephen R.; Tesoriero, Anthony J.

    2014-01-01

    Uncertainties surrounding nitrogen cycling complicate assessments of the environmental effects of nitrogen use and our understanding of the global carbon–nitrogen cycle. In this paper, we synthesize data from 877 ambient-monitoring wells across the US to frame broad patterns of nitrogen speciation and trends. At these sites, groundwater frequently contains substantial co-occurring NO3− and XSN2 (N2 from denitrification), reflecting active/ongoing denitrification and/or a mixture of undenitrified and denitrified groundwater. NO3− and NH4+ essentially do not co-occur, indicating that the dominant source of NH4+ at these sites likely is not dissimilatory reduction of NO3− to NH4+. Positive correlations of NH4+ with apparent age, CH4, dissolved organic carbon, and indicators of reduced conditions are consistent with NH4+ mobilization from degradation of aquifer organic matter and contraindicate an anthropogenic source of NH4+ for most sites. Glacial aquifers and eastern sand and gravel aquifers generally have lower proportions of NO3− and greater proportions of XSN2 than do fractured rock and karst aquifers and western sand and gravel aquifers. NO3− dominates in the youngest groundwater, but XSN2 increases as residence time increases. Temporal patterns of nitrogen speciation and concentration reflect (1) changing NO3− loads over time, (2) groundwater residence-time controls on NH4+ mobilization from solid phases, and (3) groundwater residence-time controls on denitrification. A simple classification tree using readily available variables (a national coverage of soil water depth, generalized geology) or variables reasonably estimated in many aquifers (residence time) identifies categorical denitrification extent (50%) with 79% accuracy in an independent testing set, demonstrating a predictive application based on the interconnected effects of redox, geology, and residence time.

  20. Toward a nitrogen footprint calculator for Tanzania

    Science.gov (United States)

    Hutton, Mary Olivia; Leach, Allison M.; Leip, Adrian; Galloway, James N.; Bekunda, Mateete; Sullivan, Clare; Lesschen, Jan Peter

    2017-03-01

    We present the first nitrogen footprint model for a developing country: Tanzania. Nitrogen (N) is a crucial element for agriculture and human nutrition, but in excess it can cause serious environmental damage. The Sub-Saharan African nation of Tanzania faces a two-sided nitrogen problem: while there is not enough soil nitrogen to produce adequate food, excess nitrogen that escapes into the environment causes a cascade of ecological and human health problems. To identify, quantify, and contribute to solving these problems, this paper presents a nitrogen footprint tool for Tanzania. This nitrogen footprint tool is a concept originally designed for the United States of America (USA) and other developed countries. It uses personal resource consumption data to calculate a per-capita nitrogen footprint. The Tanzania N footprint tool is a version adapted to reflect the low-input, integrated agricultural system of Tanzania. This is reflected by calculating two sets of virtual N factors to describe N losses during food production: one for fertilized farms and one for unfertilized farms. Soil mining factors are also calculated for the first time to address the amount of N removed from the soil to produce food. The average per-capita nitrogen footprint of Tanzania is 10 kg N yr-1. 88% of this footprint is due to food consumption and production, while only 12% of the footprint is due to energy use. Although 91% of farms in Tanzania are unfertilized, the large contribution of fertilized farms to N losses causes unfertilized farms to make up just 83% of the food production N footprint. In a developing country like Tanzania, the main audiences for the N footprint tool are community leaders, planners, and developers who can impact decision-making and use the calculator to plan positive changes for nitrogen sustainability in the developing world.

  1. Nitrogen solubility in the deep mantle and the origin of Earth's primordial nitrogen budget

    Science.gov (United States)

    Yoshioka, Takahiro; Wiedenbeck, Michael; Shcheka, Svyatoslav; Keppler, Hans

    2018-04-01

    be modeled. Such models show that if the magma ocean coexisted with a primordial atmosphere having a nitrogen partial pressure of just a few bars, several times the current atmospheric mass of nitrogen must have been trapped in the deep mantle. It is therefore plausible that the apparent depletion of nitrogen relative to other volatiles in the near-surface reservoirs reflects the storage of a larger reservoir of nitrogen in the solid Earth. Dynamic exchange between these reservoirs may have induced major fluctuations of bulk atmospheric pressure over Earth's history.

  2. Reflective Efficacy

    Directory of Open Access Journals (Sweden)

    Carla Bagnoli

    2018-04-01

    Full Text Available The purpose of this paper is to highlight some difficulties of Neil Sinhababu’s Humean theory of agency, which depend on his radically reductivist approach, rather than to his Humean sympathies. The argument is that Sinhababu’s theory builds upon a critique of reflective agency which is based on equivocation and misunderstandings of the Kantian approach. Ultimately, the objection is that his reductivist view is unequipped to address the rclassical problems of rational deliberation and agential authority.

  3. Climate change induces shifts in abundance and activity pattern of bacteria and archaea catalyzing major transformation steps in nitrogen turnover in a soil from a mid-European beech forest.

    Science.gov (United States)

    Gschwendtner, Silvia; Tejedor, Javier; Bimüller, Carolin; Bimueller, Carolin; Dannenmann, Michael; Kögel-Knabner, Ingrid; Knabner, Ingrid Kögel; Schloter, Michael

    2014-01-01

    Ongoing climate change will lead to more extreme weather events, including severe drought periods and intense drying rewetting cycles. This will directly influence microbial nitrogen (N) turnover rates in soil by changing the water content and the oxygen partial pressure. Therefore, a space for time climate change experiment was conducted by transferring intact beech seedling-soil mesocosms from a northwest (NW) exposed site, representing today's climatic conditions, to a southwest (SW) exposed site, providing a model climate for future conditions with naturally occurring increased soil temperature (+0.8°C in average). In addition, severe drought and intense rainfall was simulated by a rainout shelter at SW and manual rewetting after 39 days drought, respectively. Soil samples were taken in June, at the end of the drought period (August), 24 and 72 hours after rewetting (August) and after a regeneration period of four weeks (September). To follow dynamics of bacterial and archaeal communities involved in N turnover, abundance and activity of nitrifiers, denitrifiers, N2-fixing microbes and N-mineralizers was analyzed based on marker genes and the related transcripts by qPCR from DNA and RNA directly extracted from soil. Abundance of the transcripts was reduced under climate change with most pronounced effects for denitrification. Our results revealed that already a transfer from NW to SW without further treatment resulted in decreased cnor and nosZ transcripts, encoding for nitric oxide reductase and nitrous oxide reductase, respectively, while nirK transcripts, encoding for nitrite reductase, remained unaffected. Severe drought additionally led to reduced nirK and cnor transcripts at SW. After rewetting, nirK transcripts increased rapidly at both sites, while cnor and nosZ transcripts increased only at NW. Our data indicate that the climate change influences activity pattern of microbial communities involved in denitrification processes to a different extend

  4. Nitrogen isotopes in bulk marine sediment: linking seafloor observations with subseafloor records

    Directory of Open Access Journals (Sweden)

    J.-E. Tesdal

    2013-01-01

    Full Text Available The stable isotopes of nitrogen offer a unique perspective on changes in the nitrogen cycle, past and present. However, the presence of multiple forms of nitrogen in marine sediments can complicate the interpretation of bulk nitrogen isotope measurements. Although the large-scale global patterns of seafloor δ15N have been shown to match process-based expectations, small-scale heterogeneity on the seafloor, or alterations of isotopic signals during translation into the subseafloor record, could obscure the primary signals. Here, a public database of nitrogen isotope measurements is described, including both seafloor and subseafloor sediment samples ranging in age from modern to the Pliocene, and used to assess these uncertainties. In general, good agreement is observed between neighbouring seafloor sites within a 100 km radius, with 85% showing differences of < 1‰. There is also a good correlation between the δ15N of the shallowest (< 5 ka subseafloor sediments and neighbouring seafloor sites within a 100 km radius (R2 = 0.83, which suggests a reliable translation of sediments into the buried sediment record. Meanwhile, gradual δ15N decreases over multiple glacial–interglacial cycles appear to reflect post-depositional alteration in records from the deep sea (below 2000 m. We suggest a simple conceptual model to explain these 100-kyr-timescale changes in well-oxygenated, slowly accumulating sediments, which calls on differential loss rates for pools of organic N with different δ15N. We conclude that bulk sedimentary nitrogen isotope records are reliable monitors of past changes in the marine nitrogen cycle at most locations, and could be further improved with a better understanding of systematic post-depositional alteration. Furthermore, geochemical or environmental criteria should be developed in order to effectively identify problematic locations and to account for

  5. Emiliania Huxleyi (Prymnesiophyceae): Nitrogen-metabolism genes and their expression in response to external nitrogen souces

    DEFF Research Database (Denmark)

    Bruhn, Annette; LaRoche, Julie; Richardson, Katherine

    2010-01-01

    The availability and composition of dissolved nitrogen in ocean waters are factors that influence species composition in natural phytoplankton communities. The same factors affect the ratio of organic to inorganic carbon incorporation in calcifying species, such as the coccolithophore Emiliania...... huxleyi (Lohman) W. W. Hay et H. Mohler. E. huxleyi has been shown to thrive on various nitrogen sources, including dissolved organic nitrogen. Nevertheless, assimilation of dissolved nitrogen under nitrogen-replete and -limited conditions is not well understood in this ecologically important species....... In this study, the complete amino acid sequences for three functional genes involved in nitrogen metabolism in E. huxleyi were identified: a putative formamidase, a glutamine synthetase (GSII family), and assimilatory nitrate reductase. Expression patterns of the three enzymes in cells grown on inorganic...

  6. The global stoichiometry of litter nitrogen mineralization.

    Science.gov (United States)

    Manzoni, Stefano; Jackson, Robert B; Trofymow, John A; Porporato, Amilcare

    2008-08-01

    Plant residue decomposition and the nutrient release to the soil play a major role in global carbon and nutrient cycling. Although decomposition rates vary strongly with climate, nitrogen immobilization into litter and its release in mineral forms are mainly controlled by the initial chemical composition of the residues. We used a data set of approximately 2800 observations to show that these global nitrogen-release patterns can be explained by fundamental stoichiometric relationships of decomposer activity. We show how litter quality controls the transition from nitrogen accumulation into the litter to release and alters decomposers' respiration patterns. Our results suggest that decomposers lower their carbon-use efficiency to exploit residues with low initial nitrogen concentration, a strategy used broadly by bacteria and consumers across trophic levels.

  7. On Reflection

    DEFF Research Database (Denmark)

    Blasco, Maribel

    2012-01-01

    produces: that the self is accessible and transcendable, that reflexivity is universal across space and time, and that the self can act as its own remedial change agent or ‘inner consultant.’ I argue that because reflexivity is understood in many different ways, attention to definition is crucial, both...... on the concepts of selfhood that prevail and how notions of difference are constructed. First, I discuss how the dominant usages of reflexivity in intercultural education reflect and reproduce a Cartesian view of the self that shapes how ICC is conceptualized and taught. I discuss three assumptions that this view...

  8. Inspiring Reflections

    DEFF Research Database (Denmark)

    Muchie, Mammo

    2011-01-01

    A numberof Chris Freeman's colleagues were asked to reflect on what they thought describes his life and work in a few words. Some of the colleagues replied including former SPRU students that were taught or supervised by Chris Freeman. Their views on what they thought were Chris Freeman's defining...... life is not free from fluctuations, cycles, disruptions, crises and destructions both human and ecological. Innovation research ought to position itself to address environmental, financial and economic crises. The third is innovation research for development by addressing not only poverty erdaication...

  9. Reflective Writing

    DEFF Research Database (Denmark)

    Ahrenkiel Jørgensen, Andriette

    2016-01-01

    In Breve fra min Have (Letters from my Garden), the Swedish landscape architect, Sven-Ingvar Andersson, produces dialogues about his garden to a wide circle of friends, colleagues, deceased and still living acquaintances such as Karen Blixen, Gertrude Stein, C. Th. Sørensen, Albrecht Dürer, Peter...... Høeg etetera. The dialogues work as a tool of reflection in terms of providing opportunity to examine his own beliefs, to explore the possible reasons for engaging in a particular activity. On the basis of Sven-Ingvar Andersson’s book a teaching program at the Aarhus School of Architecture provides...

  10. Reflective Packaging

    Science.gov (United States)

    1994-01-01

    The aluminized polymer film used in spacecraft as a radiation barrier to protect both astronauts and delicate instruments has led to a number of spinoff applications. Among them are aluminized shipping bags, food cart covers and medical bags. Radiant Technologies purchases component materials and assembles a barrier made of layers of aluminized foil. The packaging reflects outside heat away from the product inside the container. The company is developing new aluminized lines, express mailers, large shipping bags, gel packs and insulated panels for the building industry.

  11. Biome-scale nitrogen fixation strategies selected by climatic constraints on nitrogen cycle.

    Science.gov (United States)

    Sheffer, Efrat; Batterman, Sarah A; Levin, Simon A; Hedin, Lars O

    2015-11-23

    Dinitrogen fixation by plants (in symbiosis with root bacteria) is a major source of new nitrogen for land ecosystems(1). A long-standing puzzle(2) is that trees capable of nitrogen fixation are abundant in nitrogen-rich tropical forests, but absent or restricted to early successional stages in nitrogen-poor extra-tropical forests. This biome-scale pattern presents an evolutionary paradox(3), given that the physiological cost(4) of nitrogen fixation predicts the opposite pattern: fixers should be out-competed by non-fixers in nitrogen-rich conditions, but competitively superior in nitrogen-poor soils. Here we evaluate whether this paradox can be explained by the existence of different fixation strategies in tropical versus extra-tropical trees: facultative fixers (capable of downregulating fixation(5,6) by sanctioning mutualistic bacteria(7)) are common in the tropics, whereas obligate fixers (less able to downregulate fixation) dominate at higher latitudes. Using a game-theoretic approach, we assess the ecological and evolutionary conditions under which these fixation strategies emerge, and examine their dependence on climate-driven differences in the nitrogen cycle. We show that in the tropics, transient soil nitrogen deficits following disturbance and rapid tree growth favour a facultative strategy and the coexistence of fixers and non-fixers. In contrast, sustained nitrogen deficits following disturbance in extra-tropical forests favour an obligate fixation strategy, and cause fixers to be excluded in late successional stages. We conclude that biome-scale differences in the abundance of nitrogen fixers can be explained by the interaction between individual plant strategies and climatic constraints on the nitrogen cycle over evolutionary time.

  12. Neutron reflectivity

    Directory of Open Access Journals (Sweden)

    Cousin Fabrice

    2015-01-01

    Full Text Available The specular neutron reflectivity is a technique enabling the measurement of neutron scattering length density profile perpendicular to the plane of a surface or an interface, and thereby the profile of chemical composition. The characteristic sizes that are probed range from around 5 Å up 5000 Å. It is a scattering technique that averages information on the entire surface and it is therefore not possible to obtain information within the plane of the interface. The specific properties of neutrons (possibility of tuning the contrast by isotopic substitution, sensitivity to magnetism, negligible absorption, low energy of the incident neutrons makes it particularly interesting in the fields of soft matter, biophysics and magnetic thin films. This course is a basic introduction to the technique and does not address the magnetic reflectivity. It is composed of three parts describing respectively its principle and its formalism, the experimental aspects of the method (spectrometers, samples and two examples related to the materials for energy.

  13. Understanding Nitrogen Fixation

    Energy Technology Data Exchange (ETDEWEB)

    Paul J. Chirik

    2012-05-25

    The purpose of our program is to explore fundamental chemistry relevant to the discovery of energy efficient methods for the conversion of atmospheric nitrogen (N{sub 2}) into more value-added nitrogen-containing organic molecules. Such transformations are key for domestic energy security and the reduction of fossil fuel dependencies. With DOE support, we have synthesized families of zirconium and hafnium dinitrogen complexes with elongated and activated N-N bonds that exhibit rich N{sub 2} functionalization chemistry. Having elucidated new methods for N-H bond formation from dihydrogen, C-H bonds and Broensted acids, we have since turned our attention to N-C bond construction. These reactions are particularly important for the synthesis of amines, heterocycles and hydrazines with a range of applications in the fine and commodity chemicals industries and as fuels. One recent highlight was the discovery of a new N{sub 2} cleavage reaction upon addition of carbon monoxide which resulted in the synthesis of an important fertilizer, oxamide, from the diatomics with the two strongest bonds in chemistry. Nitrogen-carbon bonds form the backbone of many important organic molecules, especially those used in the fertilizer and pharamaceutical industries. During the past year, we have continued our work in the synthesis of hydrazines of various substitution patterns, many of which are important precursors for heterocycles. In most instances, the direct functionalization of N{sub 2} offers a more efficient synthetic route than traditional organic methods. In addition, we have also discovered a unique CO-induced N{sub 2} bond cleavage reaction that simultaneously cleaves the N-N bond of the metal dinitrogen compound and assembles new C-C bond and two new N-C bonds. Treatment of the CO-functionalized core with weak Broensted acids liberated oxamide, H{sub 2}NC(O)C(O)NH{sub 2}, an important slow release fertilizer that is of interest to replace urea in many applications. The

  14. Reflected Glory

    Science.gov (United States)

    2011-02-01

    The nebula Messier 78 takes centre stage in this image taken with the Wide Field Imager on the MPG/ESO 2.2-metre telescope at the La Silla Observatory in Chile, while the stars powering the bright display take a backseat. The brilliant starlight ricochets off dust particles in the nebula, illuminating it with scattered blue light. Igor Chekalin was the overall winner of ESO's Hidden Treasures 2010 astrophotography competition with his image of this stunning object. Messier 78 is a fine example of a reflection nebula. The ultraviolet radiation from the stars that illuminate it is not intense enough to ionise the gas to make it glow - its dust particles simply reflect the starlight that falls on them. Despite this, Messier 78 can easily be observed with a small telescope, being one of the brightest reflection nebulae in the sky. It lies about 1350 light-years away in the constellation of Orion (The Hunter) and can be found northeast of the easternmost star of Orion's belt. This new image of Messier 78 from the MPG/ESO 2.2-metre telescope at the La Silla Observatory is based on data selected by Igor Chekalin in his winning entry to the Hidden Treasures competition [1]. The pale blue tint seen in the nebula in this picture is an accurate representation of its dominant colour. Blue hues are commonly seen in reflection nebulae because of the way the starlight is scattered by the tiny dust particles that they contain: the shorter wavelength of blue light is scattered more efficiently than the longer wavelength red light. This image contains many other striking features apart from the glowing nebula. A thick band of obscuring dust stretches across the image from the upper left to the lower right, blocking the light from background stars. In the bottom right corner, many curious pink structures are also visible, which are created by jets of material being ejected from stars that have recently formed and are still buried deep in dust clouds. Two bright stars, HD 38563A and

  15. Marine nitrogen cycle

    Digital Repository Service at National Institute of Oceanography (India)

    Naqvi, S.W.A.

    ) such as the Marine nitrogen cycle The marine nitrogen cycle. ‘X’ and ‘Y’ are intra-cellular intermediates that do not accumulate in water column. (Source: Codispoti et al., 2001) Page 1 of 3Marine nitrogen cycle - Encyclopedia of Earth 11/20/2006http://www... and nitrous oxide budgets: Moving targets as we enter the anthropocene?, Sci. Mar., 65, 85-105, 2001. Page 2 of 3Marine nitrogen cycle - Encyclopedia of Earth 11/20/2006http://www.eoearth.org/article/Marine_nitrogen_cycle square6 Gruber, N.: The dynamics...

  16. Reflection-type hologram for atoms

    International Nuclear Information System (INIS)

    Shimizu, Fujio; Fujita, Jun-ichi

    2002-01-01

    A cold metastable neon atomic beam was manipulated with a reflective amplitude hologram that was encoded on a silicon surface. A black-and-white pattern of atoms was reconstructed on a microchannel plate detector. The hologram used the enhanced quantum reflection developed by authors and was made of a two-dimensional array of rectangular low and high reflective cells. The surface of the high reflective cell was composed of regularly spaced roof-shaped ridges, while the low reflective cell was simply a flat surface. The hologram was the first demonstration of reflective atom-optical elements that used universal interaction between a neutral atom and solid surface

  17. Do oxygen isotope values in collagen reflect the ecology and physiology of neotropical mammals?

    Directory of Open Access Journals (Sweden)

    Brooke eCrowley

    2015-11-01

    Full Text Available Stable isotope data provide insight into the foraging ecology of animals. Traditionally, carbon and nitrogen isotope values have been used to infer dietary and habitat preferences. Oxygen isotopes are used less frequently but may complement the ecological information provided by carbon and nitrogen, particularly in densely forested or arid environments. Additionally, because oxygen is preserved in both bioapatite and collagen, it is useful for paleoecological studies. To investigate the suitability of oxygen isotopes for complementing and building on ecological applications of carbon and nitrogen isotopes, we analyze all three isotopes in bone collagen for nearly identical assemblages of Costa Rican mammals in two ecologically distinct habitats - a evergreen rainforest and a seasonal dry forest. We assess the degree to which differences in habitat, activity pattern, diet, arboreality, and thermoregulation are revealed by each of the isotope systems. Our results highlight the potential of oxygen isotopes in modern and paleoecological contexts. In addition to reflecting habitat type, oxygen isotope values in collagen distinguish species on the basis of vertical habitat stratification and drinking behavior. Within a locality, individuals with low oxygen isotope values likely track meteoric water, whereas those with elevated values most likely consume evaporatively-enriched plant tissues, such as canopy leaves. These patterns will be useful in reconstructing paleoenvironments and interpreting ecological differences among taxa both extant and extinct.

  18. Environmental science. The shape of nitrogen to come

    Energy Technology Data Exchange (ETDEWEB)

    Bleeker, A. [ECN Environment and Energy Engineering, 1755 ZG Petten (Netherlands); Sutton, M.A. [NERC Centre for Ecology and Hydrology CEH, Edinburgh Research Station, Edinburgh EH26 0QB (United Kingdom)

    2013-02-28

    An analysis reveals the huge impact of human activity on the nitrogen cycle in China. With global use of Earth's resources rising per head, the findings call for a re-evaluation of the consumption patterns of developed societies.

  19. Toward a mechanistic modeling of nitrogen limitation on vegetation dynamics.

    Directory of Open Access Journals (Sweden)

    Chonggang Xu

    Full Text Available Nitrogen is a dominant regulator of vegetation dynamics, net primary production, and terrestrial carbon cycles; however, most ecosystem models use a rather simplistic relationship between leaf nitrogen content and photosynthetic capacity. Such an approach does not consider how patterns of nitrogen allocation may change with differences in light intensity, growing-season temperature and CO(2 concentration. To account for this known variability in nitrogen-photosynthesis relationships, we develop a mechanistic nitrogen allocation model based on a trade-off of nitrogen allocated between growth and storage, and an optimization of nitrogen allocated among light capture, electron transport, carboxylation, and respiration. The developed model is able to predict the acclimation of photosynthetic capacity to changes in CO(2 concentration, temperature, and radiation when evaluated against published data of V(c,max (maximum carboxylation rate and J(max (maximum electron transport rate. A sensitivity analysis of the model for herbaceous plants, deciduous and evergreen trees implies that elevated CO(2 concentrations lead to lower allocation of nitrogen to carboxylation but higher allocation to storage. Higher growing-season temperatures cause lower allocation of nitrogen to carboxylation, due to higher nitrogen requirements for light capture pigments and for storage. Lower levels of radiation have a much stronger effect on allocation of nitrogen to carboxylation for herbaceous plants than for trees, resulting from higher nitrogen requirements for light capture for herbaceous plants. As far as we know, this is the first model of complete nitrogen allocation that simultaneously considers nitrogen allocation to light capture, electron transport, carboxylation, respiration and storage, and the responses of each to altered environmental conditions. We expect this model could potentially improve our confidence in simulations of carbon-nitrogen interactions and the

  20. Toward a mechanistic modeling of nitrogen limitation on vegetation dynamics.

    Science.gov (United States)

    Xu, Chonggang; Fisher, Rosie; Wullschleger, Stan D; Wilson, Cathy J; Cai, Michael; McDowell, Nate G

    2012-01-01

    Nitrogen is a dominant regulator of vegetation dynamics, net primary production, and terrestrial carbon cycles; however, most ecosystem models use a rather simplistic relationship between leaf nitrogen content and photosynthetic capacity. Such an approach does not consider how patterns of nitrogen allocation may change with differences in light intensity, growing-season temperature and CO(2) concentration. To account for this known variability in nitrogen-photosynthesis relationships, we develop a mechanistic nitrogen allocation model based on a trade-off of nitrogen allocated between growth and storage, and an optimization of nitrogen allocated among light capture, electron transport, carboxylation, and respiration. The developed model is able to predict the acclimation of photosynthetic capacity to changes in CO(2) concentration, temperature, and radiation when evaluated against published data of V(c,max) (maximum carboxylation rate) and J(max) (maximum electron transport rate). A sensitivity analysis of the model for herbaceous plants, deciduous and evergreen trees implies that elevated CO(2) concentrations lead to lower allocation of nitrogen to carboxylation but higher allocation to storage. Higher growing-season temperatures cause lower allocation of nitrogen to carboxylation, due to higher nitrogen requirements for light capture pigments and for storage. Lower levels of radiation have a much stronger effect on allocation of nitrogen to carboxylation for herbaceous plants than for trees, resulting from higher nitrogen requirements for light capture for herbaceous plants. As far as we know, this is the first model of complete nitrogen allocation that simultaneously considers nitrogen allocation to light capture, electron transport, carboxylation, respiration and storage, and the responses of each to altered environmental conditions. We expect this model could potentially improve our confidence in simulations of carbon-nitrogen interactions and the vegetation

  1. Toward a Mechanistic Modeling of Nitrogen Limitation on Vegetation Dynamics

    Science.gov (United States)

    Xu, Chonggang; Fisher, Rosie; Wullschleger, Stan D.; Wilson, Cathy J.; Cai, Michael; McDowell, Nate G.

    2012-01-01

    Nitrogen is a dominant regulator of vegetation dynamics, net primary production, and terrestrial carbon cycles; however, most ecosystem models use a rather simplistic relationship between leaf nitrogen content and photosynthetic capacity. Such an approach does not consider how patterns of nitrogen allocation may change with differences in light intensity, growing-season temperature and CO2 concentration. To account for this known variability in nitrogen-photosynthesis relationships, we develop a mechanistic nitrogen allocation model based on a trade-off of nitrogen allocated between growth and storage, and an optimization of nitrogen allocated among light capture, electron transport, carboxylation, and respiration. The developed model is able to predict the acclimation of photosynthetic capacity to changes in CO2 concentration, temperature, and radiation when evaluated against published data of Vc,max (maximum carboxylation rate) and Jmax (maximum electron transport rate). A sensitivity analysis of the model for herbaceous plants, deciduous and evergreen trees implies that elevated CO2 concentrations lead to lower allocation of nitrogen to carboxylation but higher allocation to storage. Higher growing-season temperatures cause lower allocation of nitrogen to carboxylation, due to higher nitrogen requirements for light capture pigments and for storage. Lower levels of radiation have a much stronger effect on allocation of nitrogen to carboxylation for herbaceous plants than for trees, resulting from higher nitrogen requirements for light capture for herbaceous plants. As far as we know, this is the first model of complete nitrogen allocation that simultaneously considers nitrogen allocation to light capture, electron transport, carboxylation, respiration and storage, and the responses of each to altered environmental conditions. We expect this model could potentially improve our confidence in simulations of carbon-nitrogen interactions and the vegetation feedbacks

  2. Developments in nitrogen generators

    International Nuclear Information System (INIS)

    Ayres, C.L.; Abrardo, J.M.; Himmelberger, L.M.

    1984-01-01

    Three process cycles for the production of nitrogen by the cryogenic separation of air are described in detail. These cycles are: (1) a waste expander cycle; (2) an air expander cycle; and (3) a cycle for producing large quantities of gaseous nitrogen. Each cycle has distinct advantages for various production ranges and delivery pressures. A dicussion of key parameters that must be considered when selecting a cycle to meet specific product requirements is presented. The importance of high plant reliability and a dependable liquid nitrogen back up system is also presented. Lastly, a discussion of plant safety dealing with the hazards of nitrogen, enriched oxygen, and hydrocarbons present in the air is reviewed

  3. Recent Nitrogen Deposition In Poland Monitored With The Moss Pleurozium Schreberi

    Directory of Open Access Journals (Sweden)

    Kapusta Paweł

    2014-07-01

    Full Text Available In this study, atmospheric deposition of nitrogen was determined for Poland by moss biomonitoring. Nitrogen content was measured in the moss Pleurozium schreberi (Willd. ex Brid. Mitt. sampled in 2010 from 320 sites evenly distributed throughout the country. Mosses (green parts contained an average 1.56% nitrogen. The result places Poland among the European countries most polluted by airborne nitrogen. The highest nitrogen concentrations were found in mosses from the central and southern parts of the country, and the lowest in samples from some eastern and northern regions. Multiple regression showed that this variability was due mostly to nitrogen emissions from agricultural and industrial areas (moss nitrogen was positively associated with the consumption of mineral nitrogen fertilizers and the magnitude of particulate pollution. Some details of the spatial variability of the nitrogen data indicate that local and regional point sources of pollution (e.g., chemical plants played an important role in shaping the nitrogen deposition pattern

  4. Is a Nitrogen-rich Reference Needed for Canopy Sensor-based Corn Nitrogen Applications?

    Science.gov (United States)

    The nitrogen (N) supplying capacity of the soil available to support corn (Zea mays L.) production can be highly variable both among and within fields. In recent years, canopy reflectance sensing has been investigated for in-season assessment of crop N health and fertilization. Typically, the proced...

  5. Xylem sap nitrogen compounds of some Crotalaria species

    Directory of Open Access Journals (Sweden)

    Vitória Angela Pierre

    1999-01-01

    Full Text Available Thirteen species of Crotalaria were analysed for nitrogen compounds in the xylem root bleeding sap. Amino acids were the main form of organic nitrogen found, but only traces of ureides were present. Of the four species analysed for amino acid composition, asparagine was found to be the major amino acid, accounting for over 68% of the nitrogen transported. No striking deviations from this general pattern was found between species, between vegetative and floral stages of development, or between nodulated and non-nodulated plants. It was concluded that the Crotalaria species studied here have an asparagine-based nitrogen metabolism, consistent with many other non-ureide-producing legume species.

  6. Uptake of fertilizer nitrogen and soil nitrogen by rice using 15N-labelled nitrogen fertilizer

    International Nuclear Information System (INIS)

    Reddy, K.R.; Patrick, W.H. Jr.

    1980-01-01

    Data from five field experiments using labelled nitrogen fertilizer were used to determine the relative effects of soil nitrogen and fertilizer nitrogen on rice yield. Yield of grain was closely correlated with total aboveground nitrogen uptake (soil + fertilizer), less closely correlated with soil nitrogen uptake and not significantly correlated with fertilizer nitrogen uptake. When yield increase rather than yield was correlated with fertilizer nitrogen uptake, the correlation coefficient was statistically significant. (orig.)

  7. Nitrogen trading tool

    Science.gov (United States)

    The nitrogen cycle is impacted by human activities, including those that increase the use of nitrogen in agricultural systems, and this impact can be seen in effects such as increased nitrate (NO3) levels in groundwater or surface water resources, increased concentration of nitrous oxide (N2O) in th...

  8. Nitrogen use efficiency (NUE)

    NARCIS (Netherlands)

    Oenema, O.

    2015-01-01

    There is a need for communications about resource use efficiency and for measures to increase the use efficiency of nutrients in relation to food production. This holds especially for nitrogen. Nitrogen (N) is essential for life and a main nutrient element. It is needed in relatively large

  9. Nitrogen in Chinese coals

    Science.gov (United States)

    Wu, D.; Lei, J.; Zheng, B.; Tang, X.; Wang, M.; Hu, Jiawen; Li, S.; Wang, B.; Finkelman, R.B.

    2011-01-01

    Three hundred and six coal samples were taken from main coal mines of twenty-six provinces, autonomous regions, and municipalities in China, according to the resource distribution and coal-forming periods as well as the coal ranks and coal yields. Nitrogen was determined by using the Kjeldahl method at U. S. Geological Survey (USGS), which exhibit a normal frequency distribution. The nitrogen contents of over 90% Chinese coal vary from 0.52% to 1.41% and the average nitrogen content is recommended to be 0.98%. Nitrogen in coal exists primarily in organic form. There is a slight positive relationship between nitrogen content and coal ranking. ?? 2011 Science Press, Institute of Geochemistry, CAS and Springer Berlin Heidelberg.

  10. Enhancing biological nitrogen fixation

    Energy Technology Data Exchange (ETDEWEB)

    Danso, S.K.A.; Eskew, D.L. (Joint FAO/IAEA Div. of Isotope and Radiation Applications of Atomic Energy for Food and Agricultural Development, Vienna (Austria))

    1984-06-01

    Several co-ordinated research programmes (CRPs) conducted by the Soil Fertility, Irrigation and Crop Production Section of the Joint FAO/IAEA Division have concentrated on finding the most efficient way of applying nitrogen fertilizers to various crops, using nitrogen-15 (/sup 15/N) as a tracer. The findings of these studies have been adopted in many countries around the world, resulting in savings of nitrogen fertilizers worth many millions of dollars every year. More recently, the Section's CRPs have focused on enhancing the natural process of biological di-nitrogen fixation. The /sup 15/N isotope technique has proven to be very valuable in studies of the legume-Rhizobium symbiosis, allowing many more experiments than before to be done and yielding much new practical information. The Soils Section is now working to extend the use of the technique to other nitrogen-fixing symbioses.

  11. Modeling nitrogen fluxes in Germany - where does the nitrogen go?

    Science.gov (United States)

    Klement, Laura; Bach, Martin; Breuer, Lutz

    2016-04-01

    patterns of the groundwater bodies which fail the good WFD status, the N-surplus or the measured data. The parameters for denitrification and the percolation rate seemed to have a higher model sensitivity than the nitrogen surplus. MoRE was previously validated only for the total N load from groundwater into surface water but the modeling concept for nitrate concentration was seemingly never fitted to observed data and needs refinements. A literature research showed that no groundwater concentrations modeled with MoRE or MONERIS have been published for Germany until now. Instead, only the concentration in percolating water was shown - sometimes misleadingly labeled so that the reader could presume the map displayed groundwater concentrations. According to the MoRE approach, model parameters such as the percolation rate and denitrification intensity are more sensitive than the N surplus. The surplus can indicate only a potential leaching risk, while the actual threat varies substantially with regional soil and climate conditions. Consequently, the use of the nitrogen surplus as a sole indicator for nitrate leaching should be critically examined. For conception of nitrate reduction programs obviously the regionally varying site conditions cannot be disregarded.

  12. Demonstrating Paramagnetism Using Liquid Nitrogen.

    Science.gov (United States)

    Simmonds, Ray; And Others

    1994-01-01

    Describes how liquid nitrogen is attracted to the poles of neodymium magnets. Nitrogen is not paramagnetic, so the attraction suggests that the liquid nitrogen contains a small amount of oxygen, which causes the paramagnetism. (MVL)

  13. Challenging Narcissus, or Reflecting on Reflecting.

    Science.gov (United States)

    Achilles, C. M.

    The concept of reflective practice and teaching people to be reflective practitioners is examined. The document begins with a look at professional knowledge according to three prominent professionals in the educational administration field: Schon, Schein, and Achilles. "Reflective" strategies that could be incorporated into courses and…

  14. Spectral measurements at different spatial scales in potato: relating leaf, plant and canopy nitrogen status

    Science.gov (United States)

    Jongschaap, Raymond E. E.; Booij, Remmie

    2004-09-01

    Chlorophyll contents in vegetation depend on soil nitrogen availability and on crop nitrogen uptake, which are important management factors in arable farming. Crop nitrogen uptake is important, as nitrogen is needed for chlorophyll formation, which is important for photosynthesis, i.e. the conversion of absorbed radiance into plant biomass. The objective of this study was to estimate leaf and canopy nitrogen contents by near and remote sensing observations and to link observations at leaf, plant and canopy level. A theoretical base is presented for scaling-up leaf optical properties to whole plants and crops, by linking different optical recording techniques at leaf, plant and canopy levels through the integration of vertical nitrogen distribution. Field data come from potato experiments in The Netherlands in 1997 and 1998, comprising two potato varieties: Eersteling and Bintje, receiving similar nitrogen treatments (0, 100, 200 and 300 kg N ha -1) in varying application schemes to create differences in canopy nitrogen status during the growing season. Ten standard destructive field samplings were performed to follow leaf area index and crop dry weight evolution. Samples were analysed for inorganic nitrogen and total nitrogen contents. At sampling dates, spectral measurements were taken both at leaf level and at canopy level. At leaf level, an exponential relation between SPAD-502 readings and leaf organic nitrogen contents with a high correlation factor of 0.91 was found. At canopy level, an exponential relation between canopy organic nitrogen contents and red edge position ( λrep, nm) derived from reflectance measurements was found with a good correlation of 0.82. Spectral measurements (SPAD-502) at leaf level of a few square mm were related to canopy reflectance measurements (CropScan™) of approximately 0.44 m 2. Statistical regression techniques were used to optimise theoretical vertical nitrogen profiles that allowed scaling-up leaf chlorophyll measurements

  15. Food, Feed and Fuel: a Story About Nitrogen

    Science.gov (United States)

    Galloway, J. N.; Burke, M. B.; Mooney, H. A.; Steinfeld, H.

    2008-12-01

    Humans obtain metabolic energy by eating food. Nitrogen is required to grow food, but natural supplies of N for human purposes have been inadequate since the beginning of the twentieth century. The Haber-Bosch process now provides a virtually inexhaustible supply of nitrogen, limited primarily by the cost of energy. However, most nitrogen used in food production is lost to the environment, where it cascades through environmental reservoirs contributing to many of the major environmental issues of the day. Furthermore, growing international trade in nitrogen-containing commodities is increasingly replacing wind and water as an important international transporter of nitrogen around the globe. Finally, the rapid growth in crop-based biofuels, and its attendant effects on the global production and trade of all agricultural commodities, could greatly affect global patterns of N use and loss. In the light of the findings above, this paper examines the role of nitrogen in food, feed and fuel production. It describes the beneficial consequences for food production and the negative consequences associated with the commodity nitrogen cascade and the environmental nitrogen cascade. The paper reviews estimates of future projections of nitrogen demands for food and fuel, including the impact of changing diets in the developing world. The paper concludes by presenting the potential interactions among global change, agricultural production and the nitrogen and carbon cycles.

  16. Reflectance spectra of subarctic lichens

    International Nuclear Information System (INIS)

    Petzold, D.E.; Goward, S.N.

    1988-01-01

    Lichens constitute a major portion of the ground cover of high latitude environments, but little has been reported concerning their in situ solar spectral reflectance properties. Knowledge of these properties is important for the interpretation of remotely sensed observations from high latitude regions, as well as in studies of high latitude ecology and energy balance climatology. The spectral reflectance of common boreal vascular plants is similar to that of vascular plants of the mid latitudes. The dominant lichens, in contrast, display variable reflectance patterns in visible wavelengths. The relative reflectance peak at 0.55 μm, common to green vegetation, is absent or indistinct in spectra of pervasive boreal forest and tundra lichens, despite the presence of chlorophyll in the inner algal cells. Lichens of the dominant genus, Cladina, display strong absorption of ultraviolet energy and short-wavelength blue light relative to their absorption in other visible wavelengths. Since the Cladinae dominate both the surface vegetation in open woodlands of the boreal forest and the low arctic tundra, their unusual spectral reflectance patterns will enable accurate monitoring of the boreal forest-tundra ecotone and detection of its vigor and movement in the future. (author)

  17. Reflectance spectra of subarctic lichens

    Science.gov (United States)

    Petzold, Donald E.; Goward, Samuel N.

    1988-01-01

    Lichens constitute a major portion of the ground cover of high latitude environments, but little has been reported concerning their in situ solar spectral reflectance properties. Knowledge of these properties is important for the interpretation of remotely sensed observations from high latitude regions, as well as in studies of high latitude ecology and energy balance climatology. The spectral reflectance of common boreal vascular plants is similar to that of vascular plants of the midlatitudes. The dominant lichens, in contrast, display variable reflectance patterns in visible wavelengths. The relative reflectance peak at 0.55 microns, common to green vegetation, is absent or indistinct in spectra of pervasive boreal forest and tundra lichens, despite the presence of chlorophyll in the inner algal cells. Lichens of the dominant genus, Cladina, display strong absorption of ultraviolet energy and short-wavelength blue light relative to their absorption in other visible wavelengths. Since the Cladinae dominate both the surface vegetation in open woodlands of the boreal forest and the low arctic tundra, their unusual spectral reflectance patterns will enable accurate monitoring of the boreal forest-tundra ecotone and detection of its vigor and movement in the future.

  18. The nitrogen cycle.

    Science.gov (United States)

    Stein, Lisa Y; Klotz, Martin G

    2016-02-08

    Nitrogen is the fourth most abundant element in cellular biomass, and it comprises the majority of Earth's atmosphere. The interchange between inert dinitrogen gas (N2) in the extant atmosphere and 'reactive nitrogen' (those nitrogen compounds that support, or are products of, cellular metabolism and growth) is entirely controlled by microbial activities. This was not the case, however, in the primordial atmosphere, when abiotic reactions likely played a significant role in the inter-transformation of nitrogen oxides. Although such abiotic reactions are still important, the extant nitrogen cycle is driven by reductive fixation of dinitrogen and an enzyme inventory that facilitates dinitrogen-producing reactions. Prior to the advent of the Haber-Bosch process (the industrial fixation of N2 into ammonia, NH3) in 1909, nearly all of the reactive nitrogen in the biosphere was generated and recycled by microorganisms. Although the Haber-Bosch process more than quadrupled the productivity of agricultural crops, chemical fertilizers and other anthropogenic sources of fixed nitrogen now far exceed natural contributions, leading to unprecedented environmental degradation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Carbon and nitrogen stoichiometry across stream ecosystems

    Science.gov (United States)

    Wymore, A.; Kaushal, S.; McDowell, W. H.; Kortelainen, P.; Bernhardt, E. S.; Johnes, P.; Dodds, W. K.; Johnson, S.; Brookshire, J.; Spencer, R.; Rodriguez-Cardona, B.; Helton, A. M.; Barnes, R.; Argerich, A.; Haq, S.; Sullivan, P. L.; López-Lloreda, C.; Coble, A. A.; Daley, M.

    2017-12-01

    Anthropogenic activities are altering carbon and nitrogen concentrations in surface waters globally. The stoichiometry of carbon and nitrogen regulates important watershed biogeochemical cycles; however, controls on carbon and nitrogen ratios in aquatic environments are poorly understood. Here we use a multi-biome and global dataset (tropics to Arctic) of stream water chemistry to assess relationships between dissolved organic carbon (DOC) and nitrate, ammonium and dissolved organic nitrogen (DON), providing a new conceptual framework to consider interactions between DOC and the multiple forms of dissolved nitrogen. We found that across streams the total dissolved nitrogen (TDN) pool is comprised of very little ammonium and as DOC concentrations increase the TDN pool shifts from nitrate to DON dominated. This suggests that in high DOC systems, DON serves as the primary source of nitrogen. At the global scale, DOC and DON are positively correlated (r2 = 0.67) and the average C: N ratio of dissolved organic matter (molar ratio of DOC: DON) across our data set is approximately 31. At the biome and smaller regional scale the relationship between DOC and DON is highly variable (r2 = 0.07 - 0.56) with the strongest relationships found in streams draining the mixed temperate forests of the northeastern United States. DOC: DON relationships also display spatial and temporal variability including latitudinal and seasonal trends, and interactions with land-use. DOC: DON ratios correlated positively with gradients of energy versus nutrient limitation pointing to the ecological role (energy source versus nutrient source) that DON plays with stream ecosystems. Contrary to previous findings we found consistently weak relationships between DON and nitrate which may reflect DON's duality as an energy or nutrient source. Collectively these analyses demonstrate how gradients of DOC drive compositional changes in the TDN pool and reveal a high degree of variability in the C: N ratio

  20. Reflective masks for extreme ultraviolet lithography

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, Khanh Bao [Univ. of California, Berkeley, CA (United States)

    1994-05-01

    Extreme ultraviolet lithographic masks are made by patterning multilayer reflective coatings with high normal incidence reflectivity. Masks can be patterned by depositing a patterned absorber layer above the coating or by etching the pattern directly into the coating itself. Electromagnetic simulations showed that absorber-overlayer masks have superior imaging characteristics over etched masks (less sensitive to incident angles and pattern profiles). In an EUVL absorber overlayer mask, defects can occur in the mask substrate, reflective coating, and absorber pattern. Electromagnetic simulations showed that substrate defects cause the most severe image degradation. A printability study of substrate defects for absorber overlayer masks showed that printability of 25 nm high substrate defects are comparable to defects in optical lithography. Simulations also indicated that the manner in which the defects are covered by multilayer reflective coatings can affect printability. Coverage profiles that result in large lateral spreading of defect geometries amplify the printability of the defects by increasing their effective sizes. Coverage profiles of Mo/Si coatings deposited above defects were studied by atomic force microscopy and TEM. Results showed that lateral spread of defect geometry is proportional to height. Undercut at defect also increases the lateral spread. Reductions in defect heights were observed for 0.15 μm wide defect lines. A long-term study of Mo/Si coating reflectivity revealed that Mo/Si coatings with Mo as the top layer suffer significant reductions in reflectivity over time due to oxidation.

  1. Mineral commodity profiles: nitrogen

    Science.gov (United States)

    Kramer, Deborah A.

    2004-01-01

    Overview -- Nitrogen (N) is an essential element of life and a part of all animal and plant proteins. As a part of the DNA and RNA molecules, nitrogen is an essential constituent of each individual's genetic blueprint. As an essential element in the chlorophyll molecule, nitrogen is vital to a plant's ability to photosynthesize. Some crop plants, such as alfalfa, peas, peanuts, and soybeans, can convert atmospheric nitrogen into a usable form by a process referred to as 'fixation.' Most of the nitrogen that is available for crop production, however, comes from decomposing animal and plant waste or from commercially produced fertilizers. Commercial fertilizers contain nitrogen in the form of ammonium and/or nitrate or in a form that is quickly converted to the ammonium or nitrate form once the fertilizer is applied to the soil. Ammonia is generally the source of nitrogen in fertilizers. Anhydrous ammonia is commercially produced by reacting nitrogen with hydrogen under high temperatures and pressures. The source of nitrogen is the atmosphere, which is almost 80 percent nitrogen. Hydrogen is derived from a variety of raw materials, which include water, and crude oil, coal, and natural gas hydrocarbons. Nitrogen-based fertilizers are produced from ammonia feedstocks through a variety of chemical processes. Small quantities of nitrates are produced from mineral resources principally in Chile. In 2002, anhydrous ammonia and other nitrogen materials were produced in more than 70 countries. Global ammonia production was 108 million metric tons (Mt) of contained nitrogen. With 28 percent of this total, China was the largest producer of ammonia. Asia contributed 46 percent of total world ammonia production, and countries of the former U.S.S.R. represented 13 percent. North America also produced 13 percent of the total; Western Europe, 9 percent; the Middle East, 7 percent; Central America and South America, 5 percent; Eastern Europe, 3 percent; and Africa and Oceania

  2. Commercial Nitrogen Fertilizer Purchased

    Data.gov (United States)

    U.S. Environmental Protection Agency — Amounts of fertilizer nitrogen (N) purchased by states in individual years 2003, 2005, 2007, 2009 and 2011, and the % change in average amounts purchased per year...

  3. NEMA, a functional-structural model of nitrogen economy within wheat culms after flowering. II. Evaluation and sensitivity analysis.

    Science.gov (United States)

    Bertheloot, Jessica; Wu, Qiongli; Cournède, Paul-Henry; Andrieu, Bruno

    2011-10-01

    Simulating nitrogen economy in crop plants requires formalizing the interactions between soil nitrogen availability, root nitrogen acquisition, distribution between vegetative organs and remobilization towards grains. This study evaluates and analyses the functional-structural and mechanistic model of nitrogen economy, NEMA (Nitrogen Economy Model within plant Architecture), developed for winter wheat (Triticum aestivum) after flowering. NEMA was calibrated for field plants under three nitrogen fertilization treatments at flowering. Model behaviour was investigated and sensitivity to parameter values was analysed. Nitrogen content of all photosynthetic organs and in particular nitrogen vertical distribution along the stem and remobilization patterns in response to fertilization were simulated accurately by the model, from Rubisco turnover modulated by light intercepted by the organ and a mobile nitrogen pool. This pool proved to be a reliable indicator of plant nitrogen status, allowing efficient regulation of nitrogen acquisition by roots, remobilization from vegetative organs and accumulation in grains in response to nitrogen treatments. In our simulations, root capacity to import carbon, rather than carbon availability, limited nitrogen acquisition and ultimately nitrogen accumulation in grains, while Rubisco turnover intensity mostly affected dry matter accumulation in grains. NEMA enabled interpretation of several key patterns usually observed in field conditions and the identification of plausible processes limiting for grain yield, protein content and root nitrogen acquisition that could be targets for plant breeding; however, further understanding requires more mechanistic formalization of carbon metabolism. Its strong physiological basis and its realistic behaviour support its use to gain insights into nitrogen economy after flowering.

  4. The influence of nitrogen inputs on biomass and trophic structure of ocean plankton: a study using biomass and stable isotope size-spectra

    KAUST Repository

    Mompeán, Carmen

    2016-08-18

    Large scale patterns in planktonic food web structure were studied by applying continuous size-scaled models of biomass and δ15N to plankton samples, collected at 145 stations during the Malaspina-2010 Expedition across three ocean basins and including major biomes. Carbon biomass and δ15N were determined in size-fractionated samples (40 to 5000 μm) collected by vertical hauls (0–200 m). Biomass-normalized size-spectra were constructed to summarize food web structure and spatial patterns in spectral parameters were analyzed using geographically-weighted regression analysis. Except in the northwestern Atlantic, size-spectra showed low variability, reflecting a homogeneity in nitrogen sources and food web structure for the central oceans. Estimated predator-to-prey mass ratios <104 and mean trophic transfer efficiency values between 16% (coastal biome) and >20% (Trades and Westerlies biomes) suggested that oceanic plankton food webs may support a larger number of trophic levels than current estimates based on high efficiency values. The largest changes in spectral parameters and nitrogen sources were related to inputs of atmospheric nitrogen, either from diazotrophic organisms or dust deposition. These results suggest geographic homogeneity in the net transfer of nitrogen up the food web.

  5. Brucella, nitrogen and virulence.

    Science.gov (United States)

    Ronneau, Severin; Moussa, Simon; Barbier, Thibault; Conde-Álvarez, Raquel; Zuniga-Ripa, Amaia; Moriyon, Ignacio; Letesson, Jean-Jacques

    2016-08-01

    The brucellae are α-Proteobacteria causing brucellosis, an important zoonosis. Although multiplying in endoplasmic reticulum-derived vacuoles, they cause no cell death, suggesting subtle but efficient use of host resources. Brucellae are amino-acid prototrophs able to grow with ammonium or use glutamate as the sole carbon-nitrogen source in vitro. They contain more than twice amino acid/peptide/polyamine uptake genes than the amino-acid auxotroph Legionella pneumophila, which multiplies in a similar vacuole, suggesting a different nutritional strategy. During these two last decades, many mutants of key actors in nitrogen metabolism (transporters, enzymes, regulators, etc.) have been described to be essential for full virulence of brucellae. Here, we review the genomic and experimental data on Brucella nitrogen metabolism and its connection with virulence. An analysis of various aspects of this metabolism (transport, assimilation, biosynthesis, catabolism, respiration and regulation) has highlighted differences and similarities in nitrogen metabolism with other α-Proteobacteria. Together, these data suggest that, during their intracellular life cycle, the brucellae use various nitrogen sources for biosynthesis, catabolism and respiration following a strategy that requires prototrophy and a tight regulation of nitrogen use.

  6. Nitrogen footprints: past, present and future

    Science.gov (United States)

    Galloway, James N.; Winiwarter, Wilfried; Leip, Adrian; Leach, Allison M.; Bleeker, Albert; Willem Erisman, Jan

    2014-11-01

    The human alteration of the nitrogen cycle has evolved from minimal in the mid-19th century to extensive in the present time. The consequences to human and environmental health are significant. While much attention has been given to the extent and impacts of the alteration, little attention has been given to those entities (i.e., consumers, institutions) that use the resources that result in extensive reactive nitrogen (Nr) creation. One strategy for assessment is the use of nitrogen footprint tools. A nitrogen footprint is generally defined as the total amount of Nr released to the environment as a result of an entity’s consumption patterns. This paper reviews a number of nitrogen footprint tools (N-Calculator, N-Institution, N-Label, N-Neutrality, N-Indicator) that are designed to provide that attention. It reviews N-footprint tools for consumers as a function of the country that they live in (N-Calculator, N-Indicator) and the products they buy (N-Label), for the institutions that people work in and are educated in (N-Institution), and for events and decision-making regarding offsets (N-Neutrality). N footprint tools provide a framework for people to make decisions about their resource use and show them how offsets can be coupled with behavior change to decrease consumer/institution contributions to N-related problems.

  7. Nitrogen footprints: past, present and future

    International Nuclear Information System (INIS)

    Galloway, James N; Leach, Allison M; Winiwarter, Wilfried; Leip, Adrian; Bleeker, Albert; Erisman, Jan Willem

    2014-01-01

    The human alteration of the nitrogen cycle has evolved from minimal in the mid-19th century to extensive in the present time. The consequences to human and environmental health are significant. While much attention has been given to the extent and impacts of the alteration, little attention has been given to those entities (i.e., consumers, institutions) that use the resources that result in extensive reactive nitrogen (Nr) creation. One strategy for assessment is the use of nitrogen footprint tools. A nitrogen footprint is generally defined as the total amount of Nr released to the environment as a result of an entity’s consumption patterns. This paper reviews a number of nitrogen footprint tools (N-Calculator, N-Institution, N-Label, N-Neutrality, N-Indicator) that are designed to provide that attention. It reviews N-footprint tools for consumers as a function of the country that they live in (N-Calculator, N-Indicator) and the products they buy (N-Label), for the institutions that people work in and are educated in (N-Institution), and for events and decision-making regarding offsets (N-Neutrality). N footprint tools provide a framework for people to make decisions about their resource use and show them how offsets can be coupled with behavior change to decrease consumer/institution contributions to N-related problems. (paper)

  8. [Effects of nitrogen and irrigation water application on yield, water and nitrogen utilization and soil nitrate nitrogen accumulation in summer cotton].

    Science.gov (United States)

    Si, Zhuan Yun; Gao, Yang; Shen, Xiao Jun; Liu, Hao; Gong, Xue Wen; Duan, Ai Wang

    2017-12-01

    NO 3 - -N accumulation layer moved downward. By comprehensively considering above-ground biomass, seed cotton yield, water and nitrogen uptake and utilization, and soil NO 3 - -N accumulation in the soil profile, the treatment N 3 I 1 could be recommended as the optimal water and nitrogen application pattern for summer cotton production in the experimental region.

  9. Chemical patterning on preformed porous silicon photonic crystals: towards multiplex detection of protease activity at precise positions†Electronic supplementary information (ESI) available: SEM images, XPS result and more optical reflectivity data. See DOI: 10.1039/c4tb00281dClick here for additional data file.

    Science.gov (United States)

    Zhu, Ying; Soeriyadi, Alexander H; Parker, Stephen G; Reece, Peter J; Gooding, J Justin

    2014-06-21

    Porous silicon (PSi) rugate filters modified with alkyne-terminated monolayers were chemically patterned using a combination of photolithography of photoresist and click chemistry. Two chemical functionalities were obtained by conjugating, via click reactions, ethylene glycol moieties containing two different terminal groups to discrete areas towards the exterior of a PSi rugate filter. The patterning of biological species to the functionalized surface was demonstrated through the conjugation of fluorescein isothiocyanate labelled bovine serum albumin (FITC-BSA). Fluorescence microscopy showed selective positioning of FITC-BSA at discretely functionalized areas. Meanwhile, the optical information from precisely defined positions on the patterned surface was monitored by optical reflectivity measurements. The optical measurements revealed successful step-wise chemical functionalization followed by immobilization of gelatin. Multiplex detection of protease activity from different array elements on the patterned surface was demonstrated by monitoring the blue shifts in the reflectivity spectra resulted from the digestion of gelatin by subtilisin. Precise information from both individual elements and average population was acquired. This technique is important for the development of PSi into a microarray platform for highly parallel biosensing applications, especially for cell-based assays.

  10. Human Decisions: Nitrogen Footprints and Environmental Effects

    Science.gov (United States)

    Leach, A. M.; Bleeker, A.; Galloway, J. N.; Erisman, J.

    2012-12-01

    Human consumption choices are responsible for growing losses of reactive nitrogen (Nr) to the environment. Once in the environment, Nr can cause a cascade of negative impacts such as smog, acid rain, coastal eutrophication, climate change, and biodiversity loss. Although all humans must consume nitrogen as protein, the food production process releases substantial Nr to the environment. This dilemma presents a challenge: how do we feed a growing population while reducing Nr? Although top-down strategies to reduce Nr losses (e.g., emissions controls) are necessary, the bottom-up strategies focusing on personal consumption patterns will be imperative to solve the nitrogen challenge. Understanding the effects of different personal choices on Nr losses and the environment is an important first step for this strategy. This paper will utilize information and results from the N-Calculator, a per capita nitrogen footprint model (www.N-Print.org), to analyze the impact of different food consumption patterns on a personal food nitrogen footprint and the environment. Scenarios will analyze the impact of the following dietary patterns on the average United States (28 kg Nr/cap/yr) food nitrogen footprint: 1) Consuming only the recommended protein as defined by the WHO and the USDA; 2) Reducing food waste by 50%; 3) Consuming a vegetarian diet; 4) Consuming a vegan diet; 5) Consuming a demitarian diet (replacing half of animal protein consumption with vegetable protein); 6) Substituting chicken (a more efficient animal protein) with beef (a less efficient animal protein); 7) Consuming sustainably-produced food; and 8) Using advanced wastewater treatment. Preliminary results suggest that widespread advanced wastewater treatment with nutrient removal technology and halving food waste would each reduce the US personal food nitrogen footprint by 13%. In addition, reducing protein consumption to the recommended levels would reduce the footprint by about 42%. Combining these measures

  11. Estimating foliar nitrogen in Eucalyptus using vegetation indexes

    Directory of Open Access Journals (Sweden)

    Luiz Felipe Ramalho de Oliveira

    Full Text Available ABSTRACT Nitrogen (N has commonly been applied in Eucalyptus stands in Brazil and it has a direct relation with biomass production and chlorophyll content. Foliar N concentrations are used to diagnose soil and plant fertility levels and to develop N fertilizer application rates. Normally, foliar N is obtained using destructive methods, but indirect analyses using Vegetation Indexes (VIs may be possible. The aim of this work was to evaluate VIs to estimate foliar N concentration in three Eucalyptus clones. Lower crown leaves of three clonal Eucalyptus plantations (25 months old were classified into five color patterns using the Munsell Plant Tissue Color Chart. For each color, N concentration was determined by the Kjeldahl method and foliar reflectance was measured using a CI-710 Miniature Leaf Spectrometer. Foliar reflectance data were used to obtain the VIs and the VIs were used to estimate N concentrations. In the visible region, the relationship between N concentration and reflectance percentage was negative. The highest correlations between VIs and N concentrations were obtained by the Inflection Point Position (IPP, r = 0.97, Normalized Difference Red-Edge (reNDVI, r = 0.97 and Modified Red-Edge Normalized Difference Vegetation Index (mNDI, r = 0.97. Vegetation indexes on the red edge region provided the most accurate estimates of foliar N concentration. The reNDVI index provided the best N concentration estimates in leaves of different colors of Eucalyptus urophylla × grandis and Eucalyptus urophylla × urophylla (R2 = 0.97 and RMSE = 0.91 g kg−1.

  12. The nitrogen cycle: Atmosphere interactions

    Science.gov (United States)

    Levine, J. S.

    1984-01-01

    Atmospheric interactions involving the nitrogen species are varied and complex. These interactions include photochemical reactions, initiated by the absorption of solar photons and chemical kinetic reactions, which involve both homogeneous (gas-to-gas reactions) and heterogeneous (gas-to-particle) reactions. Another important atmospheric interaction is the production of nitrogen oxides by atmospheric lightning. The nitrogen cycle strongly couples the biosphere and atmosphere. Many nitrogen species are produced by biogenic processes. Once in the atmosphere nitrogen oxides are photochemically and chemically transformed to nitrates, which are returned to the biosphere via precipitation, dry deposition and aerosols to close the biosphere-atmosphere nitrogen cycle. The sources, sinks and photochemistry/chemistry of the nitrogen species; atmospheric nitrogen species; souces and sinks of nitrous oxide; sources; sinks and photochemistry/chemistry of ammonia; seasonal variation of the vertical distribution of ammonia in the troposphere; surface and atmospheric sources of the nitrogen species, and seasonal variation of ground level ammonia are summarized.

  13. [Hyperspectral remote sensing diagnosis models of rice plant nitrogen nutritional status].

    Science.gov (United States)

    Tan, Chang-Wei; Zhou, Qing-Bo; Qi, La; Zhuang, Heng-Yang

    2008-06-01

    The correlations of rice plant nitrogen content with raw hyperspectral reflectance, first derivative hyperspectral reflectance, and hyperspectral characteristic parameters were analyzed, and the hyperspectral remote sensing diagnosis models of rice plant nitrogen nutritional status with these remote sensing parameters as independent variables were constructed and validated. The results indicated that the nitrogen content in rice plant organs had a variation trend of stem plant nitrogen nutritional status, with the decisive coefficients (R2) being 0.7996 and 0.8606, respectively; while the model with vegetation index (SDr - SDb) / (SDr + SDb) as independent variable, i. e., y = 365.871 + 639.323 ((SDr - SDb) / (SDr + SDb)), was most fit rice plant nitrogen content, with R2 = 0.8755, RMSE = 0.2372 and relative error = 11.36%, being able to quantitatively diagnose the nitrogen nutritional status of rice.

  14. Forest fuel reduces the nitrogen load - calculations of nitrogen flows

    International Nuclear Information System (INIS)

    Burstroem, F.; Johansson, Jan.

    1995-12-01

    Nitrogen deposition in Sweden has increased strongly during recent decades, particularly in southern Sweden. Nitrogen appears to be largely accumulated in biomass and in the soil. It is therefore desirable to check the accumulation of nitrogen in the forest. The most suitable way of doing this is to remove more nitrogen-rich biomass from the forest, i.e., increase the removal of felling residues from final fellings and cleanings. An ecological condition for intensive removal of fuel is that the ashes are returned. The critical load for nitrogen, CL(N), indicates the level of nitrogen deposition that the forest can withstand without leading to ecological changes. Today, nitrogen deposition is higher than the CL(N) in almost all of Sweden. CL(N) is calculated in such a manner that nitrogen deposition should largely be balanced by nitrogen losses through harvesting during a forest rotation. The value of CL(N) thus largely depends on how much nitrogen is removed with the harvested biomass. When both stems and felling residues are harvested, the CL(N) is about three times higher than in conventional forestry. The increase is directly related to the amount of nitrogen in the removed biofuel. Use of biofuel also causes a certain amount of nitrogen emissions. From the environmental viewpoint there is no difference between the sources of the nitrogen compounds. An analysis of the entire fuel chain shows that, compared with the amount of nitrogen removed from the forest with the fuel, about 5 % will be emitted as nitrogen oxides or ammonia during combustion, and a further ca 5 % during handling and transports. A net amount of about 90 % of biomass nitrogen is removed from the system and becomes inert nitrogen (N 2 ). 60 refs, 3 figs, 4 tabs, 11 appendices

  15. Nitrogen frost migration on Triton: A historical model

    International Nuclear Information System (INIS)

    Spencer, J.R.

    1990-01-01

    The author presents the results of numerical simulations of the seasonal migration of nitrogen frost on Triton, constrained by Voyager observations of atmospheric pressure, temperature, and albedo distribution. Most of the exposed nitrogen is probably seasonal frost, whose migration can produce major variations in atmospheric pressure. For instance, models explored here predict a tenfold pressure drop in the coming decade. The observed albedo patterns can be understood if fresh nitrogen frost is relatively dark butt brightens with increasing insolation in a manner analogous to the Martian southern CO 2 cap

  16. Nitrogen nutrition of the grape-vine (Vitis vinifera spp)

    International Nuclear Information System (INIS)

    Conradie, W.J.

    1985-12-01

    A thorough knowledge concerning the nitrogen relationship in the grape-vine is essential in order to appreciate how different patterns of uptake, assimilation, storage and utilisation of nitrogen might be advantageous in particular environmental situations. The 15 N-isotope technique has been used to determine the uptake and distribution of nitrogen absorbed during early spring, early summer and autumn. Apart from the total N fraction, protein N and soluble N were determined as well. The utilisation of labelled N applied in the field, was determined for vineyards on heavier and lighter soils

  17. Molecular nitrogen fixation and nitrogen cycle in nature

    Energy Technology Data Exchange (ETDEWEB)

    Virtanen, A I

    1952-01-01

    The origin of nitrogen oxides in the atmosphere is discussed. Evidently only a small proportion of the nitrate-and nitrite-nitrogen found in the precipitation is formed through electric discharges from molecular nitrogen, photochemical nitrogen fixation being probably of greater importance. Formation of nitrate nitrogen through atmospheric oxidation of nitrous oxide (N/sub 2/O) evaporating from the soil is also considered likely. Determination of nitrogen compounds at different altitudes is indispensable for gaining information of the N/sub 2/-fixation in the atmosphere and, in general, of the origin of nitrogen oxides and their decomposition. International cooperation is needed for this as well as for the quantitative determination of the nitrogen compounds removed from the soil by leaching and brought by waters into the seas.

  18. Temperature-reflection I

    DEFF Research Database (Denmark)

    McGady, David A.

    2017-01-01

    -temperature path integrals for quantum field theories (QFTs) should be T-reflection invariant. Because multi-particle partition functions are equal to Euclidean path integrals for QFTs, we expect them to be T-reflection invariant. Single-particle partition functions though are often not invariant under T......In this paper, we revisit the claim that many partition functions are invariant under reflecting temperatures to negative values (T-reflection). The goal of this paper is to demarcate which partition functions should be invariant under T-reflection, and why. Our main claim is that finite...... that T-reflection is unrelated to time-reversal. Finally, we study the interplay between T-reflection and perturbation theory in the anharmonic harmonic oscillator in quantum mechanics and in Yang-Mills in four-dimensions. This is the first in a series of papers on temperature-reflections....

  19. Nitrogen Fixation in Cyanobacteria

    NARCIS (Netherlands)

    Stal, L.J.

    2008-01-01

    Cyanobacteria are oxygenic photosynthetic bacteria that are widespread in marine, freshwater and terrestrial environments and many of them are capable of fixing atmospheric nitrogen. But ironically, nitrogenase, the enzyme that is responsible for the reduction of N2, is extremely sensitive to O2.

  20. Replaceable liquid nitrogen piping

    International Nuclear Information System (INIS)

    Yasujima, Yasuo; Sato, Kiyoshi; Sato, Masataka; Hongo, Toshio

    1982-01-01

    This liquid nitrogen piping with total length of about 50 m was made and installed to supply the liquid nitrogen for heat insulating shield to three superconducting magnets for deflection and large super-conducting magnet for detection in the π-meson beam line used for high energy physics experiment in the National Laboratory for High Energy Physics. The points considered in the design and manufacture stages are reported. In order to minimize the consumption of liquid nitrogen during transport, vacuum heat insulation method was adopted. The construction period and cost were reduced by the standardization of the components, the improvement of welding works and the elimination of ineffective works. For simplifying the maintenance, spare parts are always prepared. The construction and the procedure of assembling of the liquid nitrogen piping are described. The piping is of double-walled construction, and its low temperature part was made of SUS 316L. The super-insulation by aluminum vacuum evaporation and active carbon were attached on the external surface of the internal pipe. The final leak test and the heating degassing were performed. The tests on evacuation, transport capacity and heat entry are reported. By making the internal pipe into smaller size, the piping may be more efficient. (Kako, I.)

  1. Nitrogen availability for nitrogen fixing cyanobacteria upon growth ...

    African Journals Online (AJOL)

    The filamentous cyanobacterium Nostoc PCC 7120 is able to convert dinitrogen to ammonia in the absence of combined nitrogen. The expression of 20% of coding sequences from all major metabolic categories was examined in nitrogen fixing and non-nitrogen fixing growth conditions. The expression data were correlated ...

  2. Low temperature delays timing and enhances the cost of nitrogen fixation in the unicellular cyanobacterium Cyanothece

    NARCIS (Netherlands)

    Brauer, V.S.; Stomp, M.; Rosso, C.; van Beusekom, S.A.M.; Emmerich, B.; Stal, L.J.; Huisman, J.

    2013-01-01

    Marine nitrogen-fixing cyanobacteria are largely confined to the tropical and subtropical ocean. It has been argued that their global biogeographical distribution reflects the physiologically feasible temperature range at which they can perform nitrogen fixation. In this study we refine this line of

  3. Liberating Moral Reflection

    Science.gov (United States)

    Horell, Harold D.

    2013-01-01

    The author argues that if we are to foster life-giving and liberating moral reflection, we must first liberate moral reflection from distortions; specifically, from the distorting effects of moral insensitivity, destructive moral relativism, and confusions resulting from a failure to understand the dynamics of moral reflection. The author proposes…

  4. The Global Nitrogen Cycle

    Science.gov (United States)

    Galloway, J. N.

    2003-12-01

    Once upon a time nitrogen did not exist. Today it does. In the intervening time the universe was formed, nitrogen was created, the Earth came into existence, and its atmosphere and oceans were formed! In this analysis of the Earth's nitrogen cycle, I start with an overview of these important events relative to nitrogen and then move on to the more traditional analysis of the nitrogen cycle itself and the role of humans in its alteration.The universe is ˜15 Gyr old. Even after its formation, there was still a period when nitrogen did not exist. It took ˜300 thousand years after the big bang for the Universe to cool enough to create atoms; hydrogen and helium formed first. Nitrogen was formed in the stars through the process of nucleosynthesis. When a star's helium mass becomes great enough to reach the necessary pressure and temperature, helium begins to fuse into still heavier elements, including nitrogen.Approximately 10 Gyr elapsed before Earth was formed (˜4.5 Ga (billion years ago)) by the accumulation of pre-assembled materials in a multistage process. Assuming that N2 was the predominate nitrogen species in these materials and given that the temperature of space is -270 °C, N2 was probably a solid when the Earth was formed since its boiling point (b.p.) and melting point (m.p.) are -196 °C and -210 °C, respectively. Towards the end of the accumulation period, temperatures were probably high enough for significant melting of some of the accumulated material. The volcanic gases emitted by the resulting volcanism strongly influenced the surface environment. Nitrogen was converted from a solid to a gas and emitted as N2. Carbon and sulfur were probably emitted as CO and H2S (Holland, 1984). N2 is still the most common nitrogen volcanic gas emitted today at a rate of ˜2 TgN yr-1 (Jaffee, 1992).Once emitted, the gases either remained in the atmosphere or were deposited to the Earth's surface, thus continuing the process of biogeochemical cycling. The rate of

  5. Crop sensors for automation of in-season nitrogen application

    Science.gov (United States)

    Crop canopy reflectance sensing can be used to assess in-season crop nitrogen (N) health for automatic control of N fertilization. Typically, sensor data are processed to an established index, such as the Normalized Difference Vegetative Index (NDVI) and differences in that index from a well-fertili...

  6. Simulation Tool for GNSS Ocean Surface Reflections

    DEFF Research Database (Denmark)

    Høeg, Per; von Benzon, Hans-Henrik; Durgonics, Tibor

    2015-01-01

    GNSS coherent and incoherent reflected signals have the potential of deriving large scale parameters of ocean surfaces, as barotropic variability, eddy currents and fronts, Rossby waves, coastal upwelling, mean ocean surfaceheights, and patterns of the general ocean circulation. In the reflection...... zone the measurements may deriveparameters as sea surface roughness, winds, waves, heights and tilts from the spectral measurements. Previous measurements from the top of mountains and airplanes have shown such results leading.The coming satellite missions, CYGNSS, COSMIC-2, and GEROS...

  7. Historical nitrogen content of bryophyte tissue as an indicator of increased nitrogen deposition in the Cape Metropolitan Area, South Africa

    International Nuclear Information System (INIS)

    Wilson, D.; Stock, W.D.; Hedderson, T.

    2009-01-01

    Information on changes in precipitation chemistry in the rapidly expanding Cape Metropolitan Area (CMA) of South Africa is scarce. To obtain a long-term record of N deposition we investigated changes in moss foliar N, C:N ratios and nitrogen isotope values that might reflect precipitation chemistry. Tissue from 9 species was obtained from herbarium specimens collected between 1875 and 2000 while field samples were collected in 2001/2002. There is a strong trend of increasing foliar N content in all mosses collected over the past century (1.32-1.69 %N). Differences exist between ectohydric mosses which have higher foliar N than the mixohydric group. C:N ratios declined while foliar δ 15 N values showed no distinct pattern. From relationships between moss tissue N and N deposition rates we estimated an increase of 6-13 kg N ha -1 a -1 since 1950. Enhanced N deposition rates of this magnitude could lead to biodiversity losses in native ecosystems. - This study of bryophyte tissue nutrient contents shows a historical increase in N deposition rates to the low nutrient adapted plant biodiversity hotspot in the Western Cape, South Africa

  8. Historical nitrogen content of bryophyte tissue as an indicator of increased nitrogen deposition in the Cape Metropolitan Area, South Africa

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, D. [Botany Department, University of Cape Town, Rondebosch 7701 (South Africa); Stock, W.D. [Botany Department, University of Cape Town, Rondebosch 7701 (South Africa); Centre for Ecosystem Management, School of Natural Sciences, Edith Cowan University, 100 Joondalup Drive, Joondalup, Perth, WA 6027 (Australia)], E-mail: w.stock@ecu.edu.au; Hedderson, T. [Botany Department, University of Cape Town, Rondebosch 7701 (South Africa)

    2009-03-15

    Information on changes in precipitation chemistry in the rapidly expanding Cape Metropolitan Area (CMA) of South Africa is scarce. To obtain a long-term record of N deposition we investigated changes in moss foliar N, C:N ratios and nitrogen isotope values that might reflect precipitation chemistry. Tissue from 9 species was obtained from herbarium specimens collected between 1875 and 2000 while field samples were collected in 2001/2002. There is a strong trend of increasing foliar N content in all mosses collected over the past century (1.32-1.69 %N). Differences exist between ectohydric mosses which have higher foliar N than the mixohydric group. C:N ratios declined while foliar {delta}{sup 15}N values showed no distinct pattern. From relationships between moss tissue N and N deposition rates we estimated an increase of 6-13 kg N ha{sup -1} a{sup -1} since 1950. Enhanced N deposition rates of this magnitude could lead to biodiversity losses in native ecosystems. - This study of bryophyte tissue nutrient contents shows a historical increase in N deposition rates to the low nutrient adapted plant biodiversity hotspot in the Western Cape, South Africa.

  9. Inter-species and intra-annual variations of moss nitrogen utilization: Implications for nitrogen deposition assessment.

    Science.gov (United States)

    Dong, Yu-Ping; Liu, Xue-Yan; Sun, Xin-Chao; Song, Wei; Zheng, Xu-Dong; Li, Rui; Liu, Cong-Qiang

    2017-11-01

    Moss nitrogen (N) concentrations and natural 15 N abundance (δ 15 N values) have been widely employed to evaluate annual levels and major sources of atmospheric N deposition. However, different moss species and one-off sampling were often used among extant studies, it remains unclear whether moss N parameters differ with species and different samplings, which prevented more accurate assessment of N deposition via moss survey. Here concentrations, isotopic ratios of bulk carbon (C) and bulk N in natural epilithic mosses (Bryum argenteum, Eurohypnum leptothallum, Haplocladium microphyllum and Hypnum plumaeforme) were measured monthly from August 2006 to August 2007 at Guiyang, SW China. The H. plumaeforme had significantly (P < 0.05) lower bulk N concentrations and higher δ 13 C values than other species. Moss N concentrations were significantly (P < 0.05) lower in warmer months than in cooler months, while moss δ 13 C values exhibited an opposite pattern. The variance component analyses showed that different species contributed more variations of moss N concentrations and δ 13 C values than different samplings. Differently, δ 15 N values did not differ significantly between moss species, and its variance mainly reflected variations of assimilated N sources, with ammonium as the dominant contributor. These results unambiguously reveal the influence of inter-species and intra-annual variations of moss N utilization on N deposition assessment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Liquid nitrogen fire extinguishing system test report

    International Nuclear Information System (INIS)

    Beidelman, J.A.

    1972-01-01

    The objective of this test series was to demonstrate the feasibility of using liquid nitrogen as a fire-extinguishing agent for certain types of metal fires. It was intended to provide data and experience appropriate to the design of a second series which will test the applicability of this technique to plutonium fires and which will develop more detailed operating information and permit more precise measurement of test parameters-oxygen depletion rates and equilibrium concentrations, temperature effects, and nitrogen pressures, flow rates, spray methods and patterns, etc. The test series was directed specifically toward extinguishment of metal fires occurring in well-confined areas and was not intended to be representative of any larger classification. Fires of several types were tested, e.g., magnesium, mixed magnesium and zirconium, sodium and cerium

  11. Phosphate glasses, containing nitrogen

    International Nuclear Information System (INIS)

    Lisitsyna, E.A.; Khalilev, V.D.; Koryavin, A.A.; Goncharova, L.N.

    1987-01-01

    Possibilities of nitrogen-containing glass synthesis by the introduction into the charge of ammonium salts, as well as aluminium nitride, are studied. Zinc alumoyttrium phosphate glass (mol. %) Zn(PO 3 ) 2 - 4O, Al(PO 3 ) 3 - 3O, Y(PO 3 ) 3 -3O is suggested as a matrix. It is shown that the effect of amide and imide groups on the properties of the glass is less noticeable than the effect of nitride groups. Direct introduction of nitride constituent was realized using AlN, but aluminium introduction was taken into account so that the oxide was subtracted. The attempt to introduce more than 2.5 mass % of nitrogen into initial matrix by aluminium nitride has failed due to repeated restoration of glass with amorphous phosphorus isolation

  12. The fertilizer nitrogen problem

    Energy Technology Data Exchange (ETDEWEB)

    Olson, R A; Halstead, E H

    1974-07-01

    A world-wide fossil fuel crisis has surfaced in the past year by reason of shortage and high cost, which is felt throughout all segments of human society. Nor has the agriculture sector, with its very high demand for energy to supply its power, machinery, fertilizer, processing and transport, escaped the energy crisis. Among the agricultural inputs, fertilizer nitrogen is one of major concern. This commodity is currently in extremely short supply, world prices having more than doubled in the past year alone. Serious as this situation is to agricultural production in the highly developed countries of the world, it is a real disaster to the production potential of the developing countries. The birth of the 'Green Revolution' in those countries in the last ten years came about from an amalgamation of higher yielding varieties, improved pest and disease control, better crop watering practices, and the introduction of fertilizer nitrogen. Shortcomings in any one of these requisites invalidates the entire package. (author)

  13. The fertilizer nitrogen problem

    International Nuclear Information System (INIS)

    Olson, R.A.; Halstead, E.H.

    1974-01-01

    A world-wide fossil fuel crisis has surfaced in the past year by reason of shortage and high cost, which is felt throughout all segments of human society. Nor has the agriculture sector, with its very high demand for energy to supply its power, machinery, fertilizer, processing and transport, escaped the energy crisis. Among the agricultural inputs, fertilizer nitrogen is one of major concern. This commodity is currently in extremely short supply, world prices having more than doubled in the past year alone. Serious as this situation is to agricultural production in the highly developed countries of the world, it is a real disaster to the production potential of the developing countries. The birth of the 'Green Revolution' in those countries in the last ten years came about from an amalgamation of higher yielding varieties, improved pest and disease control, better crop watering practices, and the introduction of fertilizer nitrogen. Shortcomings in any one of these requisites invalidates the entire package. (author)

  14. Motor Patterns in Walking.

    Science.gov (United States)

    Lacquaniti, F.; Grasso, R.; Zago, M.

    1999-08-01

    Despite the fact that locomotion may differ widely in mammals, common principles of kinematic control are at work. These reflect common mechanical and neural constraints. The former are related to the need to maintain balance and to limit energy expenditure. The latter are related to the organization of the central pattern-generating networks.

  15. Organic carbon and nitrogen availability determine bacterial community composition in paddy fields of the Indo-Gangetic plain.

    Science.gov (United States)

    Kumar, Arvind; Rai, Lal Chand

    2017-07-01

    Soil quality is an important factor and maintained by inhabited microorganisms. Soil physicochemical characteristics determine indigenous microbial population and rice provides food security to major population of the world. Therefore, this study aimed to assess the impact of physicochemical variables on bacterial community composition and diversity in conventional paddy fields which could reflect a real picture of the bacterial communities operating in the paddy agro-ecosystem. To fulfill the objective; soil physicochemical characterization, bacterial community composition and diversity analysis was carried out using culture-independent PCR-DGGE method from twenty soils distributed across eight districts. Bacterial communities were grouped into three clusters based on UPGMA cluster analysis of DGGE banding pattern. The linkage of measured physicochemical variables with bacterial community composition was analyzed by canonical correspondence analysis (CCA). CCA ordination biplot results were similar to UPGMA cluster analysis. High levels of species-environment correlations (0.989 and 0.959) were observed and the largest proportion of species data variability was explained by total organic carbon (TOC), available nitrogen, total nitrogen and pH. Thus, results suggest that TOC and nitrogen are key regulators of bacterial community composition in the conventional paddy fields. Further, high diversity indices and evenness values demonstrated heterogeneity and co-abundance of the bacterial communities.

  16. Nitrogen Oxide Fluxes and Nitrogen Cycling during Postagricultural Succession and Forest Fertilization in the Humid Tropics.

    Science.gov (United States)

    Heather Erickson; Michael Keller; Eric Davidson

    2001-01-01

    The effects of changes in tropical land use on soil emissions of nitrous oxide (N2O) and nitric oxide (NO) are not well understood. We examined emissions of N2O and NO and their relationships to land use and forest composition, litterfall, soil nitrogen (N) pools and turnover, soil moisture, and patterns of carbon (C) cycling in a lower montane, subtropical wet region...

  17. Nitrogen Research Programme STOP

    International Nuclear Information System (INIS)

    Erisman, J.W.; Van der Eerden, L.

    2000-01-01

    Nitrogen pollution is one of the main threats to the environment now in the Netherlands as well as other parts of Europe. In order to address the main gaps on the issues of nitrogen pollution related to the local scale, the Ministries of Housing, Physical Planning and Environment (VROM) and of Agriculture, Nature Management and Fisheries (LNV) have initiated a research programme, the Dutch Nitrogen Research Programme (STOP), which aims to provide a scientific basis to develop and implement policy on a local scale for the realisation and conservation of the EHS ('Dutch Mainframe of Natural Landscapes'). The results of the programme show that the description of emissions from manure in the field is difficult to describe and show large uncertainties. On the contrary, emissions from housings could be modelled well, if local actual data were available. The OPS model to describe the dispersion and deposition was evaluated with the measurements and the limitations were quantified. It appears that the model works well on the long term, whereas on the short term (hours) and short distance (tenths of meters) there is large uncertainty, especially in complex terrain. Critical loads for nitrogen for ecosystems were evaluated. Furthermore, the effect of management options was quantified. A method to determine critical loads as a function of soil conditions, such as acidification and water availability was derived. This resulted in a combination of the soil model SMART and the so-called 'nature planner' (Natuurplanner). It was concluded that the combination of SMART, the nature planner and OPS provide a good tool to develop and support policy on the local scale. 4 refs

  18. Nitrogen saturation in stream ecosystems.

    Science.gov (United States)

    Earl, Stevan R; Valett, H Maurice; Webster, Jackson R

    2006-12-01

    The concept of nitrogen (N) saturation has organized the assessment of N loading in terrestrial ecosystems. Here we extend the concept to lotic ecosystems by coupling Michaelis-Menten kinetics and nutrient spiraling. We propose a series of saturation response types, which may be used to characterize the proximity of streams to N saturation. We conducted a series of short-term N releases using a tracer (15NO3-N) to measure uptake. Experiments were conducted in streams spanning a gradient of background N concentration. Uptake increased in four of six streams as NO3-N was incrementally elevated, indicating that these streams were not saturated. Uptake generally corresponded to Michaelis-Menten kinetics but deviated from the model in two streams where some other growth-critical factor may have been limiting. Proximity to saturation was correlated to background N concentration but was better predicted by the ratio of dissolved inorganic N (DIN) to soluble reactive phosphorus (SRP), suggesting phosphorus limitation in several high-N streams. Uptake velocity, a reflection of uptake efficiency, declined nonlinearly with increasing N amendment in all streams. At the same time, uptake velocity was highest in the low-N streams. Our conceptual model of N transport, uptake, and uptake efficiency suggests that, while streams may be active sites of N uptake on the landscape, N saturation contributes to nonlinear changes in stream N dynamics that correspond to decreased uptake efficiency.

  19. Is nitrogen the next carbon?

    Science.gov (United States)

    Battye, William; Aneja, Viney P.; Schlesinger, William H.

    2017-09-01

    Just as carbon fueled the Industrial Revolution, nitrogen has fueled an Agricultural Revolution. The use of synthetic nitrogen fertilizers and the cultivation of nitrogen-fixing crops both expanded exponentially during the last century, with most of the increase occurring after 1960. As a result, the current flux of reactive, or fixed, nitrogen compounds to the biosphere due to human activities is roughly equivalent to the total flux of fixed nitrogen from all natural sources, both on land masses and in the world's oceans. Natural fluxes of fixed nitrogen are subject to very large uncertainties, but anthropogenic production of reactive nitrogen has increased almost fivefold in the last 60 years, and this rapid increase in anthropogenic fixed nitrogen has removed any uncertainty on the relative importance of anthropogenic fluxes to the natural budget. The increased use of nitrogen has been critical for increased crop yields and protein production needed to keep pace with the growing world population. However, similar to carbon, the release of fixed nitrogen into the natural environment is linked to adverse consequences at local, regional, and global scales. Anthropogenic contributions of fixed nitrogen continue to grow relative to the natural budget, with uncertain consequences.

  20. Soil and fertilizer nitrogen

    International Nuclear Information System (INIS)

    Winteringham, F.P.W.

    1984-01-01

    As a result of the intensified practices and effectively diminishing land resources per capita, increasing weights of both native soil- and added fertilizer-nitrogen will be lost to agriculture and its products, and will find their way into the environment. Soil-nitrogen levels and contingent productivity can nevertheless be maintained in the face of these losses on the basis of improved soil-N management. In some local situations nitrate levels in water for drinking purposes are likely to continue rising. In some cases agriculture and clearance practices are only one of several sources. In others they are clearly mainly responsible. In developing countries these losses represent those of a relatively increasingly costly input. This is due to the fact that industrial fertilizer nitrogen production is a particularly high energy-consuming process. In the more advanced industrialized countries they represent an addition to the problems and costs of environmental quality and health protection. The programmes, information and data reviewed here suggest that these problems can be contained by improved and extended soil and water management in agriculture on the basis of existing technology. In particular there appears to be enormous scope for the better exploitation of existing legumes both as non-legume crop alternatives or as biofertilizers which also possess more desirable C:N ratios than chemical fertilizer

  1. Media for Reflection

    DEFF Research Database (Denmark)

    Knudsen, Morten

    2016-01-01

    This article develops the concept media for reflection in the interest of conceptualizing the interpretative frames that enable and limit reflection in management and leadership education. The concept ‘media for reflection’ allows us to conceptualize the social and cultural mediation of reflection...... without reducing reflection to an effect of the social structures and cultural norms in which it is embedded. Based on the developed theoretical framework, this article analyses how a renaissance ‘mirror for princes’ and contemporary research-based management education mediate reflection. The content...... of the mediations is analysed as well as the societal and organizational background. Furthermore, the means by which the two media enable and limit reflection in different ways is compared. Finally, the article discusses possible implications of the analysis in terms of management and leadership education....

  2. Net primary production and canopy nitrogen in a temperate forest landscape: an analysis using imaging spectroscopy, modeling and field data

    Science.gov (United States)

    Scott V. Ollinger; Marie-Louise Smith

    2005-01-01

    Understanding spatial patterns of net primary production (NPP) is central to the study of terrestrial ecosystems, but efforts are frequently hampered by a lack of spatial information regarding factors such as nitrogen availability and site history. Here, we examined the degree to which canopy nitrogen can serve as an indicator of patterns of NPP at the Bartlett...

  3. Principles of neutron reflection

    International Nuclear Information System (INIS)

    Felcher, G.P.

    1988-08-01

    Neutron reflection is perhaps the most developed branch of slow neutrons optics, which in itself is a direct consequence of the undulatory nature of the neutron. After reviewing the basic types of interactions (nuclear and magnetic) between neutrons and matter, the formalism is introduced to calculate the reflectivity from a sample composed of stacked flat layers and, inversely, to calculate the stacking from reflectivity measurements. Finally, a brief survey of the applications of neutron reflection is given, both in technology and in fundamental research. 32 refs., 6 figs

  4. Storage array reflection considerations

    International Nuclear Information System (INIS)

    Haire, M.J.; Jordan, W.C.; Taylor, R.G.

    1997-01-01

    The assumptions used for reflection conditions of single containers are fairly well established and consistently applied throughout the industry in nuclear criticality safety evaluations. Containers are usually considered to be either fully water-reflected (i.e. surrounded by 6 to 12 in. of water) for safety calculations or reflected by 1 in. of water for nominal (structural material and air) conditions. Tables and figures are usually available for performing comparative evaluations of containers under various loading conditions. Reflection considerations used for evaluating the safety of storage arrays of fissile material are not as well established

  5. Transcriptome Analysis of Polyhydroxybutyrate Cycle Mutants Reveals Discrete Loci Connecting Nitrogen Utilization and Carbon Storage in Sinorhizobium meliloti.

    Science.gov (United States)

    D'Alessio, Maya; Nordeste, Ricardo; Doxey, Andrew C; Charles, Trevor C

    2017-01-01

    the cell. The impact of carbon storage on cellular metabolism would be reflected in global transcription patterns. By investigating the transcriptomic effects of genetically disrupting genes involved in the PHB carbon storage cycle, we revealed a relationship between intracellular carbon storage and nitrogen metabolism. This work demonstrates the utility of combining transcriptome sequencing with metabolic pathway mutations for identifying underlying gene regulatory mechanisms.

  6. Polyhedral patterns

    KAUST Repository

    Jiang, Caigui; Tang, Chengcheng; Vaxman, Amir; Wonka, Peter; Pottmann, Helmut

    2015-01-01

    We study the design and optimization of polyhedral patterns, which are patterns of planar polygonal faces on freeform surfaces. Working with polyhedral patterns is desirable in architectural geometry and industrial design. However, the classical

  7. Incorporating nitrogen fixing cyanobacteria in the global biogeochemical model HAMOCC

    Science.gov (United States)

    Paulsen, Hanna; Ilyina, Tatiana; Six, Katharina

    2015-04-01

    Nitrogen fixation by marine diazotrophs plays a fundamental role in the oceanic nitrogen and carbon cycle as it provides a major source of 'new' nitrogen to the euphotic zone that supports biological carbon export and sequestration. Since most global biogeochemical models include nitrogen fixation only diagnostically, they are not able to capture its spatial pattern sufficiently. Here we present the incorporation of an explicit, dynamic representation of diazotrophic cyanobacteria and the corresponding nitrogen fixation in the global ocean biogeochemical model HAMOCC (Hamburg Ocean Carbon Cycle model), which is part of the Max Planck Institute for Meteorology Earth system model (MPI-ESM). The parameterization of the diazotrophic growth is thereby based on available knowledge about the cyanobacterium Trichodesmium spp., which is considered as the most significant pelagic nitrogen fixer. Evaluation against observations shows that the model successfully reproduces the main spatial distribution of cyanobacteria and nitrogen fixation, covering large parts of the tropical and subtropical oceans. Besides the role of cyanobacteria in marine biogeochemical cycles, their capacity to form extensive surface blooms induces a number of bio-physical feedback mechanisms in the Earth system. The processes driving these interactions, which are related to the alteration of heat absorption, surface albedo and momentum input by wind, are incorporated in the biogeochemical and physical model of the MPI-ESM in order to investigate their impacts on a global scale. First preliminary results will be shown.

  8. Nitrogen and Oxygen Isotopic Studies of the Marine Nitrogen Cycle.

    Science.gov (United States)

    Casciotti, Karen L

    2016-01-01

    The marine nitrogen cycle is a complex web of microbially mediated reactions that control the inventory, distribution, and speciation of nitrogen in the marine environment. Because nitrogen is a major nutrient that is required by all life, its availability can control biological productivity and ecosystem structure in both surface and deep-ocean communities. Stable isotopes of nitrogen and oxygen in nitrate and nitrite have provided new insights into the rates and distributions of marine nitrogen cycle processes, especially when analyzed in combination with numerical simulations of ocean circulation and biogeochemistry. This review highlights the insights gained from dual-isotope studies applied at regional to global scales and their incorporation into oceanic biogeochemical models. These studies represent significant new advances in the use of isotopic measurements to understand the modern nitrogen cycle, with implications for the study of past ocean productivity, oxygenation, and nutrient status.

  9. 21 CFR 862.1515 - Nitrogen (amino-nitrogen) test system.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Nitrogen (amino-nitrogen) test system. 862.1515... Systems § 862.1515 Nitrogen (amino-nitrogen) test system. (a) Identification. A nitrogen (amino-nitrogen) test system is a device intended to measure amino acid nitrogen levels in serum, plasma, and urine...

  10. Evaluating hillslope and riparian contributions to dissolved nitrogen (N) export from a boreal forest catchment

    Science.gov (United States)

    Blackburn, M.; Ledesma, José L. J.; Näsholm, Torgny; Laudon, Hjalmar; Sponseller, Ryan A.

    2017-02-01

    Catchment science has long held that the chemistry of small streams reflects the landscapes they drain. However, understanding the contribution of different landscape units to stream chemistry remains a challenge which frequently limits our understanding of export dynamics. For limiting nutrients such as nitrogen (N), an implicit assumption is that the most spatially extensive landscape units (e.g., uplands) act as the primary sources to surface waters, while near-stream zones function more often as sinks. These assumptions, based largely on studies in high-gradient systems or in regions with elevated inputs of anthropogenic N, may not apply to low-gradient, nutrient-poor, and peat-rich catchments characteristic of many northern ecosystems. We quantified patterns of N mobilization along a hillslope transect in a northern boreal catchment to assess the extent to which organic matter-rich riparian soils regulate the flux of N to streams. Contrary to the prevailing view of riparian functioning, we found that near-stream, organic soils supported concentrations and fluxes of ammonium (NH4+) and dissolved organic nitrogen that were much higher than the contributing upslope forest soils. These results suggest that stream N chemistry is connected to N mobilization and mineralization within the riparian zone rather than the wider landscape. Results further suggest that water table fluctuation in near-surface riparian soils may promote elevated rates of net N mineralization in these landscapes.

  11. Trends in stream nitrogen concentrations for forested reference catchments across the USA

    Science.gov (United States)

    A. Argerich; S.L. Johnson; S.D. Sebestyen; C.C. Rhoades; E. Greathouse; J.D. Knoepp; M.B. Adams; G.E. Likens; J.L. Campbell; W.H. McDowell; F.N. Scatena; G.G. Ice

    2013-01-01

    To examine whether stream nitrogen concentrations in forested reference catchments have changed over time and if patterns were consistent across the USA, we synthesized up to 44 yr of data collected from 22 catchments at seven USDA Forest Service Experimental Forests. Trends in stream nitrogen presented high spatial variability both among catchments at a site and among...

  12. Influence of forest disturbance on stable nitrogen isotope ratios in soil and vegetation profiles

    Science.gov (United States)

    Jennifer D. Knoepp; Scott R. Taylor; Lindsay R. Boring; Chelcy F. Miniat

    2015-01-01

    Soil and plant stable nitrogen isotope ratios (15 N) are influenced by atmospheric nitrogen (N) inputs and processes that regulate organic matter (OM) transformation and N cycling. The resulting 15N patterns may be useful for discerning ecosystem differences in N cycling. We studied two ecosystems; longleaf pine wiregrass (...

  13. Dissenting in Reflective Conversations

    DEFF Research Database (Denmark)

    Bjørn, Pernille; Boulus, Nina

    2011-01-01

    Reflective monitoring of research practices is essential. However, we often lack formal training in the practices of doing action research, and descriptions of actual inquiry practice are seldom included in publications. Our aim is to provide a glimpse of self-reflective practices based on our...

  14. Self-Reflection

    DEFF Research Database (Denmark)

    Fausing, Bent

    2016-01-01

    will take a look at the establishing of the modern self and possibilities of self-reflection, too. My examples will be from the so-called dark-selfies and from a new selfie form, which merge the present with the previous progressing into the future. I will discuss the media reflections as loos and/or gain...

  15. Nitrogen supply of crops by biological nitrogen fixation. 2

    International Nuclear Information System (INIS)

    Jensen, E.S.; Andersen, A.J.; Soerensen, H.; Thomsen, J.D.

    1985-02-01

    In the present work the contributions from combined N-sources and symbiotic nitrogen fixation to the nitrogen supply of field-grown peas and field beans were evaluated by means of 15 N fertilizer dilution. The effect of N-fertilizer, supplied at sowing and at different stages of plant development, on nitrogen fixation, yield and protein production in peas, was studied in pot experiments. (author)

  16. Reflection: A Socratic approach.

    Science.gov (United States)

    Van Seggelen-Damen, Inge C M; Van Hezewijk, René; Helsdingen, Anne S; Wopereis, Iwan G J H

    2017-12-01

    Reflection is a fuzzy concept. In this article we reveal the paradoxes involved in studying the nature of reflection. Whereas some scholars emphasize its discursive nature, we go further and underline its resemblance to the self-biased dialogue Socrates had with the slave in Plato's Meno . The individual and internal nature of the reflection process creates difficulty for studying it validly and reliably. We focus on methodological issues and use Hans Linschoten's view of coupled systems to identify, analyze, and interpret empirical research on reflection. We argue that researchers and research participants can take on roles in several possible system couplings. Depending on who controls the manipulation of the stimulus, who controls the measuring instrument, who interprets the measurement and the response, different types of research questions can be answered. We conclude that reflection may be validly studied by combining different couplings of experimenter, manipulation, stimulus, participant, measurement, and response.

  17. Estimating Canopy Nitrogen Concentration in Sugarcane Using Field Imaging Spectroscopy

    Directory of Open Access Journals (Sweden)

    Marc Souris

    2012-06-01

    Full Text Available The retrieval of nutrient concentration in sugarcane through hyperspectral remote sensing is widely known to be affected by canopy architecture. The goal of this research was to develop an estimation model that could explain the nitrogen variations in sugarcane with combined cultivars. Reflectance spectra were measured over the sugarcane canopy using a field spectroradiometer. The models were calibrated by a vegetation index and multiple linear regression. The original reflectance was transformed into a First-Derivative Spectrum (FDS and two absorption features. The results indicated that the sensitive spectral wavelengths for quantifying nitrogen content existed mainly in the visible, red edge and far near-infrared regions of the electromagnetic spectrum. Normalized Differential Index (NDI based on FDS(750/700 and Ratio Spectral Index (RVI based on FDS(724/700 are best suited for characterizing the nitrogen concentration. The modified estimation model, generated by the Stepwise Multiple Linear Regression (SMLR technique from FDS centered at 410, 426, 720, 754, and 1,216 nm, yielded the highest correlation coefficient value of 0.86 and Root Mean Square Error of the Estimate (RMSE value of 0.033%N (n = 90 with nitrogen concentration in sugarcane. The results of this research demonstrated that the estimation model developed by SMLR yielded a higher correlation coefficient with nitrogen content than the model computed by narrow vegetation indices. The strong correlation between measured and estimated nitrogen concentration indicated that the methods proposed in this study could be used for the reliable diagnosis of nitrogen quantity in sugarcane. Finally, the success of the field spectroscopy used for estimating the nutrient quality of sugarcane allowed an additional experiment using the polar orbiting hyperspectral data for the timely determination of crop nutrient status in rangelands without any requirement of prior

  18. Reflectivity level of radio anechoic chambers

    DEFF Research Database (Denmark)

    Appel-Hansen, Jørgen

    1973-01-01

    A comparison between the antenna-pattern comparison technique and the free-space voltage standing-wave ratio technique for evaluating the reflectivity level of radio anechoic chambers is presented. Based on an analysis of the two techniques, it is pointed out which parameters influence the measured...

  19. Nitrogen Control in VIM Melts

    Science.gov (United States)

    Jablonski, P. D.; Hawk, J. A.

    NETL has developed a design and control philosophy for the addition of nitrogen to austenitic and ferritic steels. The design approach uses CALPHAD as the centerpiece to predict the level to which nitrogen is soluble in both the melt and the solid. Applications of this technique have revealed regions of "exclusion" in which the alloy, while within specification limits of prescribed, cannot be made by conventional melt processing. Furthermore, other investigations have found that substantial retrograde solubility of nitrogen exists, which can become problematic during subsequent melt processing and/or other finishing operations such as welding. Additionally, the CALPHAD method has been used to adjust primary melt conditions. To that end, nitrogen additions have been made using chrome nitride, silicon nitride, high-nitrogen ferrochrome as well as nitrogen gas. The advantages and disadvantages of each approach will be discussed and NETL experience in this area will be summarized with respect to steel structure.

  20. Nitrogen abundance in Comet Halley

    International Nuclear Information System (INIS)

    Wyckoff, S.; Tegler, S.C.; Engel, L.

    1991-01-01

    Data on the nitrogen-containing compounds that observed spectroscopically in the coma of Comet Halley are summarized, and the elemental abundance of nitrogen in the Comet Halley nucleus is derived. It is found that 90 percent of elemental nitrogen is in the dust fraction of the coma, while in the gas fraction, most of the nitrogen is contained in NH3 and CN. The elemental nitrogen abundance in the ice component of the nucleus was found to be deficient by a factor of about 75, relative to the solar photosphere, indicating that the chemical partitioning of N2 into NH3 and other nitrogen compounds during the evolution of the solar nebula cannot account completely for the low abundance ratio N2/NH3 = 0.1, observed in the comet. It is suggested that the low N2/NH3 ratio in Comet Halley may be explained simply by physical fractionation and/or thermal diffusion. 88 refs

  1. Distribution and utilization of nitrogenated compounds explanted by the soybean nodules by plants during seeds developing

    International Nuclear Information System (INIS)

    Alencar, Severino Matias de

    1997-01-01

    An experiment was carried out, using radioisotopes, for evaluation of the leaf, schuck and seeds areas and, examination of the pattern which is used by the nitrogenated compounds explanted by the soybean nodules

  2. Isotopic composition of dissolved inorganic nitrogen in high mountain lakes: variation with altitude in the Pyrenees

    Science.gov (United States)

    Bartrons, M.; Camarero, L.; Catalan, J.

    2010-05-01

    Nitrogen deposition in remote areas has increased, but the effect on ecosystems is still poorly understood. For aquatic systems, knowledge of the main processes driving the observed variation is limited, as is knowledge of how changes in nitrogen supply affect lake biogeochemical and food web processes. Differences in dissolved inorganic nitrogen (DIN) between lakes cannot be understood without considering catchment characteristics. In mountains, catchment features (e.g., thermal conditions, land cover) vary considerably with elevation. The isotopic composition of nitrogen (δ15N) is increasingly used to study aquatic ecosystem dynamics. Here we explore the variability of δ15N in DIN in high mountain lakes and show that environmental conditions that change with altitude can affect the isotopic ratio. We measured ammonium and nitrate δ15N values in atmospheric deposition, epilimnetic water, deep chlorophyll maximum water (DCMW) and sediment pore water (SPW) from eight mountain lakes in the Pyrenees, both above and below the treeline. Lakes showed relatively uniform δ15N-NH4+ values in SPW (2.2±1.6‰), with no variation corresponding to catchment or lake characteristics. We suggest that organic matter diagenesis under similar sediment conditions is responsible for the low variation between the lakes. In the water column, the range of δ15N values was larger for ammonium (-9.4‰ to 7.4‰) than for nitrate (-11.4‰ to -3.4‰), as a result of higher variation both between and within lakes (epilimnetic vs. DCM water). For both compounds part of the difference correlated with altitude or catchment features (e.g., scree proportion). Based on concentration, chemical and isotopic tendencies, we suggest that patterns arise from the distinct relative contributions of two types of water flow paths to the lakes: one from snowpack melting, with little soil interaction; and another highly influenced by soil conditions. The snow-type flow path contributes low DIN

  3. Temperature sensitivity of nitrogen productivity

    OpenAIRE

    Ladanai, Svetlana; Ågren, Göran

    2002-01-01

    Environmental conditions control physiological processes in plants and thus their growth. The predicted global warming is expected to accelerate tree growth. However, the growth response is a complex function of several processes. To circumvent this problem we have used the nitrogen productivity (dry matter production per unit of nitrogen in the plant), which is an aggregate parameter. Data on needle dry matter, production, and nitrogen content in needles of Scots pine (Pinus sylvestris) from...

  4. Storage array reflection considerations

    International Nuclear Information System (INIS)

    Haire, M.J.; Jordan, W.C.; Taylor, R.G.

    1997-01-01

    The assumptions used for reflection conditions of single containers are fairly well established and consistently applied throughout the industry in nuclear criticality safety evaluations. Containers are usually considered to be either fully water reflected (i.e., surrounded by 6 to 12 in. of water) for safety calculations or reflected by 1 in. of water for nominal (structural material and air) conditions. Tables and figures are usually available for performing comparative evaluations of containers under various loading conditions. Reflection considerations used for evaluating the safety of storage arrays of fissile material are not as well established. When evaluating arrays, it has become more common for analysts to use calculations to demonstrate the safety of the array configuration. In performing these calculations, the analyst has considerable freedom concerning the assumptions made for modeling the reflection of the array. Considerations are given for the physical layout of the array with little or no discussion (or demonstration) of what conditions are bounded by the assumed reflection conditions. For example, an array may be generically evaluated by placing it in a corner of a room in which the opposing walls are far away. Typically, it is believed that complete flooding of the room is incredible, so the array is evaluated for various levels of water mist interspersed among array containers. This paper discusses some assumptions that are made regarding storage array reflection

  5. Nitrogen assimilation in soybean nodules, 1

    International Nuclear Information System (INIS)

    Ohyama, Takuji; Kumazawa, Kikuo

    1980-01-01

    In order to elucidate the pathways to assimilate the ammonia produced by N 2 -fixation in soybean nodules, 15 N-labeled compounds were administered to intact nodules or nodule slices pretreated with various inhibitors of nitrogen assimilation. After exposure to 15 N 2 , 15 N-incorporation into various nitrogenous compounds was investigated in attached nodules injected with methionine sulfoximine (MSX) or azaserine (AS). MSX treatment increased the 15 N content of ammonia more than 6 times, however, depressed 15 N content of most of amides and amino acids. AS treatment enhanced 15 N content of amido-N of glutamine as well as ammonia, but decreased amino-N of glutamine and most of amino acids. Experiments with nodule slices pretreated with MSX or AS solution and then fed with 15 N-labeled ammonia or amido- 15 N of glutamine showed the same trends. Aminooxyacetate inhibited nitrogen flow from glutamic acid to other amino acids. These results strongly indicate that the ammonia produced by N 2 -fixation is assimilated by GS/GOGAT system to glutamic acid and then transaminated to various amino acids in situ. 15 N-incorporation patterns in nodule slices fed with 15 N-labeled ammonia, hydroxylamine, nitrite were similar, but nitrate seemed to be reduced in a definite compartment and assimilated similarly as in intact nodules fed with 15 N 2 (author)

  6. The Reflective Foundation

    DEFF Research Database (Denmark)

    Lunde Jørgensen, Ida

    Private foundations and cultural philanthropy by élites is viewed with increasing skepticism in recent years, begging the question of the extent to which foundations reflect on their role vis a vis wider societal norms. Through the prism of the New Carlsberg Foundation, financed by the brewery...... Carlsberg A/S, the paper seeks to elucidate the way in which one culturally significant foundation from Denmark has reflected on - and legitimated - its work and investments at critical moments in the past decades. The paper indicates a foundation with a high degree of reflection on the wider societal...

  7. Long-term ecosystem nitrogen storage and soil nitrogen availability in post-fire lodgepole pine ecosystems

    Science.gov (United States)

    Erica A. H. Smithwick; Daniel M. Kashian; Michael G. Ryan; Monica G.  Turner

    2009-01-01

    Long-term, landscape patterns in inorganic nitrogen (N) availability and N stocks following infrequent, stand-replacing fire are unknown but are important for interpreting the effect of disturbances on ecosystem function. Here, we present results from a replicated chronosequence study in the Greater Yellowstone Ecosystem (Wyoming, USA) directed at measuring inorganic N...

  8. Tunnel nitrogen spill experiment

    International Nuclear Information System (INIS)

    Ageyev, A.I.; Alferov, V.N.; Mulholland, G.T.

    1983-01-01

    The Energy Saver Safety Analysis Report (SAR) found the tunnel oxygen deficiency considerations emphasized helium spills. These reports concluded the helium quickly warms and because of its low denisty, rises to the apex of the tunnel. The oxygen content below the apex and in all but the immediate vicinity of the helium spill is essentially unchanged and guarantees an undisturbed source of oxygen especially important to fallen personnel. In contrast nitrogen spills warm slower than helium due to the ratio of the enthalpy changes per unit volume spilled spread more uniformly across the tunnel cross-section when warmed because of the much smaller density difference with air, and generally provides a greater hazard than helium spills as a result. In particular there was concern that personnel that might fall to the floor for oxygen deficiency or other reasons might find less, and not more, oxygen with dire consequences. The SAR concluded tunnel nitrogen spills were under-investigated and led to this work

  9. Monitoring plant tissue nitrogen isotopes to assess nearshore inputs of nitrogen to Lake Crescent, Olympic National Park, Washington

    Science.gov (United States)

    Cox, Stephen E.; Moran, Patrick W.; Huffman, Raegan L.; Fradkin, Steven C.

    2016-05-31

    Mats of filamentous-periphytic algae present in some nearshore areas of Lake Crescent, Olympic National Park, Washington, may indicate early stages of eutrophication from nutrient enrichment of an otherwise highly oligotrophic lake. Natural abundance ratios of stable isotopes of nitrogen (δ15N) measured in plant tissue growing in nearshore areas of the lake indicate that the major source of nitrogen used by these primary producing plants is derived mainly from atmospherically fixed nitrogen in an undeveloped forested ecosystem. Exceptions to this pattern occurred in the Barnes Point area where elevated δ15N ratios indicate that effluent from septic systems also contribute nitrogen to filamentous-periphytic algae growing in the littoral zone of that area. Near the Lyre River outlet of Lake Crescent, the δ15N of filamentous-periphytic algae growing in close proximity to the spawning areas of a unique species of trout show little evidence of elevated δ15N indicating that nitrogen from on-site septic systems is not a substantial source of nitrogen for these plants. The δ15N data corroborate estimates that nitrogen input to Lake Crescent from septic sources is comparatively small relative to input from motor vehicle exhaust and vegetative sources in undeveloped forests, including litterfall, pollen, and symbiotic nitrogen fixation. The seasonal timing of blooms of filamentous-periphytic algal near the lake shoreline is also consistent with nitrogen exported from stands of red alder trees (Alnus rubra). Isotope biomonitoring of filamentous-periphytic algae may be an effective approach to monitoring the littoral zone for nutrient input to Lake Crescent from septic sources.

  10. Nitrogen fertilization and yield formation of potato during a short growing period

    Directory of Open Access Journals (Sweden)

    L. MUSTONEN

    2008-12-01

    Full Text Available The effects various rates of nitrogen application on accumulation of dry matter and nitrogen in potato (Solanum tuberosum L. were studied during a short growing period of 140–180 days, at MTT Agrifood Research Finland in 2000–2001. The treatments were 0, 60 and 120 kg N ha-1 and the potato cultivars tested were Van Gogh and Nicola. Four successive harvests were made during the course of the experiment to monitor changes in the accumulation of dry matter and nitrogen over the season. Applications of nitrogen substantially increased haulm dry matter accumulation and to an even greater extent their nitrogen contents. The highest dry matter values were generally registered at 120 kg N ha-1. Dry matter and nitrogen content of haulms started to decline during the later part of season and most nitrogen was relocated to tubers. The results suggest that an application of only 60 kg N ha-1 was sufficient to promote rapid canopy development and there were only small reductions in dry matter and nitrogen accumulation until late in the season when the canopy started to senesce as nitrogen supply diminished. Tuber yield, plant dry matter and nitrogen accumulation at maturity were related to crop nitrogen supply. Although application of the high rate, 120 N kg ha-1, resulted in a significant increase in dry matter accumulation, this was not reflected in the profit because the higher nitrogen application reduced dry matter content of tubers by 2.6% in 2000 and by 1.1% in 2001 relative to the use of 60 kg N ha-1. Apparent fertilizer nitrogen recovery values on a whole plant basis ranged from 53 to 75%. The proportion of fertilizer recovered in tubers clearly declined with increase in nitrogen supply.;

  11. Reflection of a polarized light cone

    Science.gov (United States)

    Brody, Jed; Weiss, Daniel; Berland, Keith

    2013-01-01

    We introduce a visually appealing experimental demonstration of Fresnel reflection. In this simple optical experiment, a polarized light beam travels through a high numerical-aperture microscope objective, reflects off a glass slide, and travels back through the same objective lens. The return beam is sampled with a polarizing beam splitter and produces a surprising geometric pattern on an observation screen. Understanding the origin of this pattern requires careful attention to geometry and an understanding of the Fresnel coefficients for S and P polarized light. We demonstrate that in addition to a relatively simple experimental implementation, the shape of the observed pattern can be computed both analytically and by using optical modeling software. The experience of working through complex mathematical computations and demonstrating their agreement with a surprising experimental observation makes this a highly educational experiment for undergraduate optics or advanced-lab courses. It also provides a straightforward yet non-trivial system for teaching students how to use optical modeling software.

  12. Nitrogen accumulation and residual effects of nitrogen catch crops

    DEFF Research Database (Denmark)

    Jensen, E.S.

    1991-01-01

    The nitrogen accumulation in Italian ryegrass (Lolium multiflorum Lam.), perennial ryegrass (Lolium perenne L.), white mustard (Sinapis alba L.) and tansy phacelia (Phacelia tanacetifolia L.), under- or aftersown as nitrogen catch crops to spring barley (Hordeum vulgare L.) and field pea (Pisum s...

  13. Seasonal soybean crop reflectance

    Science.gov (United States)

    Lemaster, E. W. (Principal Investigator); Chance, J. E.

    1983-01-01

    Data are presented from field measurements of 1980 including 5 acquisitions of handheld radiometer reflectance measurements, 7 complete sets of parameters for implementing the Suits mode, and other biophysical parameters to characterize the soybean canopy. LANDSAT calculations on the simulated Brazilian soybean reflectance are included along with data collected during the summer and fall on 1981 on soybean single leaf optical parameters for three irrigation treatments. Tests of the Suits vegetative canopy reflectance model for the full hemisphere of observer directions as well as the nadir direction show moderate agreement for the visible channels of the MSS and poor agreement in the near infrared channel. Temporal changes in the spectral characteristics of the single leaves were seen to occur as a function of maturity which demonstrates that the absorptance of a soybean single leaf is more a function of thetransmittancee characteristics than the seasonally consistent single leaf reflectance.

  14. Wave reflections from breakwaters

    OpenAIRE

    Dickson, William S.

    1994-01-01

    A new method is presented for estimating the reflection of a random, multi-directional sea from a coastal structure. The technique is applicable to an array of wave gauges of arbitrary geometry deployed seaward of the reflector. An expansion for small oblique wave incidence angles is used to derive an approximate relationship between measured array cross-spectra and a small number of parameters that describe the incident wave properties and the reflectivity of the structure. Model tests with ...

  15. Reproductive effects on fecal nitrogen as an index of diet quality: an experimental assessment

    Science.gov (United States)

    Monteith, Kyle B.; Monteith, Kevin L.; Bowyer, R. Terry; Leslie,, David M.; Jenks, Jonathan A.

    2014-01-01

    Concentration of fecal nitrogen has been used widely as an indicator of dietary quality for free-ranging ruminants. Differences in digestive function between species of dimorphic ungulates render interspecific comparisons of fecal nitrogen unreliable; however, whether intraspecific sexual differences in digestive function also bias this nutritional index is unknown. Our objective was to compare sex-specific variation in concentration of fecal nitrogen using male, nonlactating female, and lactating female white-tailed deer (Odocoileus virginianus) on high- and low-quality diets. During weekly trials over spring and summer (2008-2009), we monitored intake rates, collected feces twice daily, and used micro-Kjeldahl procedures to determine percent fecal nitrogen. We also determined nitrogen content of feces following a neutral detergent fiber (NDF) rinse during pre-, peak, and postlactation. Fecal nitrogen reflected general differences in dietary quality between diets; however, fecal nitrogen of lactating females in both dietary groups was lower than for males or nonlactating females throughout lactation. Nitrogen concentration following an NDF rinse also was lower for lactating females during peak lactation. We hypothesize that the remodeling of the digestive tract and increased rumination by lactating females may enhance their ability to extract nitrogen from their forage. These adjustments may expand the foraging options of lactating females by increasing their ability to process low-quality foods, but also affects the interpretation of fecal nitrogen during the season of lactation.

  16. Thoughts on Reflection (Editorial

    Directory of Open Access Journals (Sweden)

    Denise Koufogiannakis

    2010-06-01

    Full Text Available There has been some acknowledgement in the published literature that reflection is a crucial element of the evidence based library and information practice (EBLIP model we have adopted (Booth 2004, 2006; Grant 2007; Helliwell 2007. As we work through a problem and try to incorporate the best available evidence into our decision making, reflection is required at several stages, including the very identification of the problem through to our assessment of the process itself and what we have learned in order to inform future practice. However, reflection and reflective writing have not fully been integrated into the process we espouse, and very little has been done to look more closely at this element of the model and how it can be integrated into professional learning.In a recently published research article, Sen (2010 confirms the relationship between reflection and several aspects of professional practice. These include critical review and decision making, two aspects that are tied closely to the evidence based process. Sen notes: Students were more likely to show evidence of learning, self‐development, the ability to review issues crucially, awareness of their own mental functions, ability to make decision [sic] and being empowered when they had mastered the art of reflective practice and the more deeply analytical reflective writing. (p.84 EBLIP (the journal tries to incorporate elements of reflection within the articles we publish. While we clearly believe in the need for our profession to do quality research and publish that research so that it can be accessible to practitioners, we also know that research cannot be looked at in isolation. Our evidence summaries are one way of reflecting critically on previously published research, and in the same vein, our classics bring older research studies back to the foreground. This work needs to continue to be discussed and looked at for its impact on our profession.More directly, the Using

  17. Urban rivers as hotspots of regional nitrogen pollution

    International Nuclear Information System (INIS)

    Zhang, Xiaohong; Wu, Yiyun; Gu, Baojing

    2015-01-01

    Excess nitrogen inputs to terrestrial ecosystems via human activities have deteriorated water qualities on regional scales. Urban areas as settlements of over half global population, however, were usually not considered in the analysis of regional water pollution. Here, we used a 72-month monitoring data of water qualities in Hangzhou, China to test the role of urban rives in regional nitrogen pollution and how they response to the changes of human activities. Concentrations of ammonium nitrogen in urban rivers were 3–5 times higher than that in regional rivers. Urban rivers have become pools of reactive nitrogen and hotspots of regional pollution. Moreover, this river pollution is not being measured by current surface water monitoring networks that are designed to measure broader regional patterns, resulting in an underestimation of regional pollution. This is crucial to urban environment not only in China, but also in other countries, where urban rivers are seriously polluted. - Highlights: • Nitrogen concentrations in urban rivers are much higher than that in regional rivers. • Domestic wastewater is the main source of urban river pollution in Hangzhou. • Pollutant collecting and water diversion can sharply reduce the urban river pollution. - Urban river pollution is not being measured by the current monitoring networks that are designed to measure regional patterns causing an underestimation

  18. Polyhedral patterns

    KAUST Repository

    Jiang, Caigui

    2015-10-27

    We study the design and optimization of polyhedral patterns, which are patterns of planar polygonal faces on freeform surfaces. Working with polyhedral patterns is desirable in architectural geometry and industrial design. However, the classical tiling patterns on the plane must take on various shapes in order to faithfully and feasibly approximate curved surfaces. We define and analyze the deformations these tiles must undertake to account for curvature, and discover the symmetries that remain invariant under such deformations. We propose a novel method to regularize polyhedral patterns while maintaining these symmetries into a plethora of aesthetic and feasible patterns.

  19. Accounting for surface reflectance anisotropy in satellite retrievals of tropospheric NO₂

    NARCIS (Netherlands)

    Zhou, Yipin; Brunner, D.; Spurr, R.J.D.; Boersma, K.F.; Sneep, M.; Popp, C.; Buchmann, B.

    2010-01-01

    Surface reflectance is a key parameter in satellite trace gas retrievals in the UV/visible range and in particular for the retrieval of nitrogen dioxide (NO2) vertical tropospheric columns (VTCs). Current operational retrievals rely on coarse-resolution reflectance data and do not account for the

  20. The effect of high pressure on nitrogen compounds of milk

    International Nuclear Information System (INIS)

    Kielczewska, Katarzyna; Czerniewicz, Maria; Michalak, Joanna; Brandt, Waldemar

    2004-01-01

    The effect of pressurization at different pressures (from 200 to 1000 MPa, at 200 MPa intervals, t const. = 15 min) and periods of time (from 15 to 35 min, at 10 min intervals, p const. = 800 MPa) on the changes of proteins and nitrogen compounds of skimmed milk was studied. The pressurization caused an increase in the amount of soluble casein and denaturation of whey proteins. The level of nonprotein nitrogen compounds and proteoso-peptone nitrogen compounds increased as a result of the high-pressure treatment. These changes increased with an increase in pressure and exposure time. High-pressure treatment considerably affected the changes in the conformation of milk proteins, which was reflected in the changes in the content of proteins sedimenting and an increase in their degree of hydration

  1. Swivel Joint For Liquid Nitrogen

    Science.gov (United States)

    Milner, James F.

    1988-01-01

    Swivel joint allows liquid-nitrogen pipe to rotate through angle of 100 degree with respect to mating pipe. Functions without cracking hard foam insulation on lines. Pipe joint rotates on disks so mechanical stress not transmitted to thick insulation on pipes. Inner disks ride on fixed outer disks. Disks help to seal pressurized liquid nitrogen flowing through joint.

  2. Creation, Identity and Reflection

    Directory of Open Access Journals (Sweden)

    Alina Beatrice Cheşcă

    2015-05-01

    Full Text Available The paper “Creation, Identity and Reflection” approaches the identification in the “mirror” of reality with creation, in other words seeking the authors’ identity in the reflected images. Reflection means attempting to find oneself, the mirror being the main principle of creation. Many characters become interesting only when they step into the world beyond the mirror, when their faces are doubled by the other self or when their selves are returned by other characters. The narcissistic concept of the mirror, i.e. the reflection in the mirror and the representation of the mirror itself, is a recurrent one in literature, but the reflection of the self which is not the self (as it is a reflection does not necessarily appear in a mirror or in a photograph or portrait. Sometimes, the not-self is returned to the self by another person or character. As far as Oscar Wilde’s theories are concerned, the main idea is that people are interesting for their masks, not for their inner nature. What Wilde calls “inner nature” is the characters’ un-reflected self and the mask is the reflection, the self in the mirror. Some characters’ relationships develop within a fiction that they dramatically try to preserve and protect with the risk of suffering. They refuse to take off the masks which define them in the others’ minds and hearts; the narcissistic individuals (both artists and characters seek and love their own image which they project upon facts, thus creating a fictive realm.

  3. Specialization Patterns

    DEFF Research Database (Denmark)

    Schultz, Ulrik Pagh; Lawall, Julia Laetitia; Consel, Charles

    2000-01-01

    Design patterns offer many advantages for software development, but can introduce inefficiency into the final program. Program specialization can eliminate such overheads, but is most effective when targeted by the user to specific bottlenecks. Consequently, we propose that these concepts...... are complementary. Program specialization can optimize programs written using design patterns, and design patterns provide information about the program structure that can guide specialization. Concretely, we propose specialization patterns, which describe how to apply program specialization to optimize uses...... of design patterns. In this paper, we analyze the specialization opportunities provided by specific uses of design patterns. Based on the analysis of each design pattern, we define the associated specialization pattern. These specialization opportunities can be declared using the specialization classes...

  4. Dry etching technologies for reflective multilayer

    Science.gov (United States)

    Iino, Yoshinori; Karyu, Makoto; Ita, Hirotsugu; Kase, Yoshihisa; Yoshimori, Tomoaki; Muto, Makoto; Nonaka, Mikio; Iwami, Munenori

    2012-11-01

    We have developed a highly integrated methodology for patterning Extreme Ultraviolet (EUV) mask, which has been highlighted for the lithography technique at the 14nm half-pitch generation and beyond. The EUV mask is characterized as a reflective-type mask which is completely different compared with conventional transparent-type of photo mask. And it requires not only patterning of absorber layer without damaging the underlying multi reflective layers (40 Si/Mo layers) but also etching multi reflective layers. In this case, the dry etch process has generally faced technical challenges such as the difficulties in CD control, etch damage to quartz substrate and low selectivity to the mask resist. Shibaura Mechatronics ARESTM mask etch system and its optimized etch process has already achieved the maximal etch performance at patterning two-layered absorber. And in this study, our process technologies of multi reflective layers will be evaluated by means of optimal combination of process gases and our optimized plasma produced by certain source power and bias power. When our ARES™ is used for multilayer etching, the user can choose to etch the absorber layer at the same time or etch only the multilayer.

  5. Effect of Abiotic Stresses on the Nondestructive Estimation of Rice Leaf Nitrogen Concentration

    Directory of Open Access Journals (Sweden)

    Stephan M. Haefele

    2010-01-01

    Full Text Available Decision support tools for non-destructive estimation of rice crop nitrogen (N status (e.g., chlorophyll meter [SPAD] or leaf color chart [LCC] are an established technology for improved N management in irrigated systems, but their value in rainfed environments with frequent abiotic stresses remains untested. Therefore, we studied the effect of drought, salinity, phosphorus (P deficiency, and sulfur (S deficiency on leaf N estimates derived from SPAD and LCC measurements in a greenhouse experiment. Linear relations between chlorophyll concentration and leaf N concentration based on dry weight (Ndw between SPAD values adjusted for leaf thickness and Ndw and between LCC scores adjusted for leaf thickness and Ndw could be confirmed for all treatments and varieties used. Leaf spectral reflectance measurements did not show a stress-dependent change in the reflectance pattern, indicating that no specific element of the photosynthetic complex was affected by the stresses and at the stress level applied. We concluded that SPAD and LCC are potentially useful tools for improved N management in moderately unfavorable rice environments. However, calibration for the most common rice varieties in the target region is recommended to increase the precision of the leaf N estimates.

  6. Comparative use of lichens, mosses and tree bark to evaluate nitrogen deposition in Germany

    International Nuclear Information System (INIS)

    Boltersdorf, Stefanie H.; Pesch, Roland; Werner, Willy

    2014-01-01

    To compare three biomonitoring techniques for assessing nitrogen (N) pollution in Germany, 326 lichen, 153 moss and 187 bark samples were collected from 16 sites of the national N deposition monitoring network. The analysed ranges of N content of all investigated biomonitors (0.32%–4.69%) and the detected δ 15 N values (−15.2‰–1.5‰), made it possible to reveal species specific spatial patterns of N concentrations in biota to indicate atmospheric N deposition in Germany. The comparison with measured and modelled N deposition data shows that particularly lichens are able to reflect the local N deposition originating from agriculture. - Highlights: • We investigated N pollution with the help of bioindicators in Germany. • The N load was monitored with lichens, mosses and bark by tissue N content. • Main source of N pollution was revealed by tissue δ 15 N values. • Particularly the N content and δ 15 N in lichens reflected agriculture-related N deposition. - First nationwide comparison of lichens, mosses and tree bark to assess the N deposition in Germany by analysing N content and δ 15 N values

  7. Carbon: Nitrogen Interaction Regulates Expression of Genes Involved in N-Uptake and Assimilation in Brassica juncea L.

    Directory of Open Access Journals (Sweden)

    Parul Goel

    Full Text Available In plants, several cellular and metabolic pathways interact with each other to regulate processes that are vital for their growth and development. Carbon (C and Nitrogen (N are two main nutrients for plants and coordination of C and N pathways is an important factor for maintaining plant growth and development. In the present work, influence of nitrogen and sucrose (C source on growth parameters and expression of genes involved in nitrogen transport and assimilatory pathways was studied in B. juncea seedlings. For this, B. juncea seedlings were treated with four combinations of C and N source viz., N source alone (-Suc+N, C source alone (+Suc-N, with N and C source (+Suc+N or without N and C source (-Suc-N. Cotyledon size and shoot length were found to be increased in seedlings, when nitrogen alone was present in the medium. Distinct expression pattern of genes in both, root and shoot tissues was observed in response to exogenously supplied N and C. The presence or depletion of nitrogen alone in the medium leads to severe up- or down-regulation of key genes involved in N-uptake and transport (BjNRT1.1, BjNRT1.8 in root tissue and genes involved in nitrate reduction (BjNR1 and BjNR2 in shoot tissue. Moreover, expression of several genes, like BjAMT1.2, BjAMT2 and BjPK in root and two genes BjAMT2 and BjGS1.1 in shoot were found to be regulated only when C source was present in the medium. Majority of genes were found to respond in root and shoot tissues, when both C and N source were present in the medium, thus reflecting their importance as a signal in regulating expression of genes involved in N-uptake and assimilation. The present work provides insight into the regulation of genes of N-uptake and assimilatory pathway in B. juncea by interaction of both carbon and nitrogen.

  8. Carbon: Nitrogen Interaction Regulates Expression of Genes Involved in N-Uptake and Assimilation in Brassica juncea L.

    Science.gov (United States)

    Goel, Parul; Bhuria, Monika; Kaushal, Mamta

    2016-01-01

    In plants, several cellular and metabolic pathways interact with each other to regulate processes that are vital for their growth and development. Carbon (C) and Nitrogen (N) are two main nutrients for plants and coordination of C and N pathways is an important factor for maintaining plant growth and development. In the present work, influence of nitrogen and sucrose (C source) on growth parameters and expression of genes involved in nitrogen transport and assimilatory pathways was studied in B. juncea seedlings. For this, B. juncea seedlings were treated with four combinations of C and N source viz., N source alone (-Suc+N), C source alone (+Suc-N), with N and C source (+Suc+N) or without N and C source (-Suc-N). Cotyledon size and shoot length were found to be increased in seedlings, when nitrogen alone was present in the medium. Distinct expression pattern of genes in both, root and shoot tissues was observed in response to exogenously supplied N and C. The presence or depletion of nitrogen alone in the medium leads to severe up- or down-regulation of key genes involved in N-uptake and transport (BjNRT1.1, BjNRT1.8) in root tissue and genes involved in nitrate reduction (BjNR1 and BjNR2) in shoot tissue. Moreover, expression of several genes, like BjAMT1.2, BjAMT2 and BjPK in root and two genes BjAMT2 and BjGS1.1 in shoot were found to be regulated only when C source was present in the medium. Majority of genes were found to respond in root and shoot tissues, when both C and N source were present in the medium, thus reflecting their importance as a signal in regulating expression of genes involved in N-uptake and assimilation. The present work provides insight into the regulation of genes of N-uptake and assimilatory pathway in B. juncea by interaction of both carbon and nitrogen. PMID:27637072

  9. Eighth international congress on nitrogen fixation

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    This volume contains the proceedings of the Eighth International Congress on Nitrogen Fixation held May 20--26, 1990 in Knoxville, Tennessee. The volume contains abstracts of individual presentations. Sessions were entitled Recent Advances in the Chemistry of Nitrogen Fixation, Plant-microbe Interactions, Limiting Factors of Nitrogen Fixation, Nitrogen Fixation and the Environment, Bacterial Systems, Nitrogen Fixation in Agriculture and Industry, Plant Function, and Nitrogen Fixation and Evolution.

  10. Efficiency of nitrogen fertilizers for rice

    OpenAIRE

    Roger, Pierre-Armand; Grant, I.F.; Reddy, P.M.; Watanabe, I.

    1987-01-01

    The photosynthetic biomass that develops in the floodwater of wetland rice fields affects nitrogen dynamics in the ecosystem. This review summarizes available data on the nature, productivity, and composition of the photosynthetic aquatic biomass, and its major activities regarding the nitrogen cycle, i.e., nitrogen fixation by free living blue-green algae and #Azolla$, nitrogen trapping, nitrogen accumulation at the soil surface, its effect on nitrogen losses by ammonia volatilization, nitro...

  11. Biology Reflective Assessment Curriculum

    Science.gov (United States)

    Bayley, Cheryl Ann

    Often students and educators view assessments as an obligation and finality for a unit. In the current climate of high-stakes testing and accountability, the balance of time, resources and emphasis on students' scores related to assessment have been slanted considerably toward the summative side. This tension between assessment for accountability and assessment to inform teaching strains instruction and educators' ability to use that information to design learning opportunities that help students develop deeper conceptual understanding. A substantive body of research indicates that formative and reflective assessment can significantly improve student learning. Biology Reflective Assessment Curriculum (BRAC) examines support provided for high school science students through assessment practices. This investigation incorporates the usage of reflective assessments as a guiding practice for differentiated instruction and student choice. Reflective assessment is a metacognitive strategy that promotes self-monitoring and evaluation. The goals of the curriculum are to promote self-efficacy and conceptual understanding in students learning biology through developing their metacognitive awareness. BRAC was implemented in a high school biology classroom. Data from assessments, metacognitive surveys, self-efficacy surveys, reflective journals, student work, a culminating task and field notes were used to evaluate the effectiveness of the curriculum. The results suggest that students who develop their metacognitive skills developed a deeper conceptual understanding and improved feelings of self-efficacy when they were engaged in a reflective assessment unit embedded with student choice. BRAC is a tool for teachers to use assessments to assist students in becoming metacognitive and to guide student choice in learning opportunities.

  12. Anthropogenic imprints on nitrogen and oxygen isotopic composition of precipitation nitrate in a nitrogen-polluted city in southern China

    Science.gov (United States)

    Fang, Y. T.; Koba, K.; Wang, X. M.; Wen, D. Z.; Li, J.; Takebayashi, Y.; Liu, X. Y.; Yoh, M.

    2011-02-01

    Nitric acid (HNO3) or nitrate (NO3-) is the dominant sink for reactive nitrogen oxides (NOx = NO + NO2) in the atmosphere. In many Chinese cities, HNO3 is becoming a significant contributor to acid deposition. In the present study, we measured nitrogen (N) and oxygen (O) isotopic composition of NO3- in 113 precipitation samples collected from Guangzhou City in southern China over a two-year period (2008 and 2009). We attempted to better understand the spatial and seasonal variability of atmospheric NOx sources and the NO3- formation pathways in this N-polluted city in the Pearl River Delta region. The δ15N values of NO3- (versus air N2) ranged from -4.9 to +10.1‰, and averaged +3.9‰ in 2008 and +3.3‰ in 2009. Positive δ15N values were observed throughout the year, indicating the anthropogenic contribution of NOx emissions, particularly from coal combustion. Different seasonal patterns of δ15N-NO3- were observed between 2008 and 2009, which might reflect different human activities associated with the global financial crisis and the intensive preparations for the 16th Asian Games. Nitrate δ18O values (versus Vienna Standard Mean Ocean Water) varied from +33.4 to +86.5‰ (average +65.0‰ and +67.0‰ in 2008 and 2009, respectively), a range being lower than those reported for high latitude and polar areas. Sixteen percent of δ18O values was observed lower than the expected minimum of +55‰ at our study site. This was likely caused by the reaction of NO with peroxy radicals; peroxy radicals can compete with O3 to convert NO to NO2, thereby donate O atoms with much lower δ18O value than that of O3 to atmospheric NO3-. Our results highlight that the influence of human activities on atmospheric chemistry can be recorded by the N and O isotopic composition of atmospheric NO3- in a N-polluted city.

  13. Establishing an anthropogenic nitrogen baseline using Native American shell middens

    Directory of Open Access Journals (Sweden)

    Autumn eOczkowski

    2016-05-01

    Full Text Available Narragansett Bay, Rhode Island, has been heavily influenced by anthropogenic nutrients for more than 200 years. Recent efforts to improve water quality have cut sewage nitrogen (N loads to this point source estuary by more than half. Given that the bay has been heavily fertilized for longer than monitoring programs have been in place, we sought additional insight into how N dynamics in the system have historically changed. To do this, we measured the N stable isotope (δ15N values in clam shells from as early as 3000 BP to the present. Samples from Native American middens were compared with those collected locally from museums, an archaeological company, and graduate student thesis projects, during a range of time periods. Overall, δ15N values in clam shells from Narragansett Bay have increased significantly over time, reflecting known patterns of anthropogenic nutrient enrichment. Pre-colonization midden shell δ15N values were significantly lower than those post-European contact. While there were no statistical differences among shells dated from the late 15th Century to 2005, there was a significant difference between 2005 and 2015 shells, which we attribute to the higher δ15N values in the effluent associated with recent sewage treatment upgrades. In contrast, the δ15N values of shells from the southern Rhode Island coast remained constant through time; while influenced by human activities, these areas are not directly influenced by point-source sewage discharge. Overall, our results show that this isotope technique for measuring δ15N values in clam shells provides useful insight into how N dynamics in coastal ecosystems have changed during thousands of years, providing managers vital historical information when setting goals for N reduction.

  14. Long-term trends in nitrogen isotope composition and nitrogen concentration in brazilian rainforest trees suggest changes in nitrogen cycle.

    Science.gov (United States)

    Hietz, Peter; Dünisch, Oliver; Wanek, Wolfgang

    2010-02-15

    Direct or indirect anthropogenic effects on ecosystem nitrogen cycles are important components of global change. Recent research has shown that N isotopes in tree rings reflect changes in ecosystem nitrogen sources or cycles and can be used to study past changes. We analyzed trends in two tree species from a remote and pristine tropical rainforest in Brazil, using trees of different ages to distinguish between the effect of tree age and long-term trends. Because sapwood differed from heartwood in delta(15)N and N concentration and N can be translocated between living sapwood cells, long-term trends are best seen in dead heartwood. Heartwood delta(15)N in Spanish cedar (Cedrela odorata) and big-leaf mahogany (Swietenia macrophylla) increased with tree age, and N concentrations increased with age in Cedrela. Controlling for tree age, delta(15)N increased significantly during the past century even when analyzing only heartwood and after removing labile N compounds. In contrast to northern temperate and boreal forests where wood delta(15)N often decreased, the delta(15)N increase in a remote rainforest is unlikely to be a direct signal of changed N deposition. More plausibly, the change in N isotopic composition indicates a more open N cycle, i.e., higher N losses relative to internal N cycling in the forest, which could be the result of changed forest dynamics.

  15. Nitrogen in rock: Occurrences and biogeochemical implications

    Science.gov (United States)

    Holloway, J.M.; Dahlgren, R.A.

    2002-01-01

    There is a growing interest in the role of bedrock in global nitrogen cycling and potential for increased ecosystem sensitivity to human impacts in terrains with elevated background nitrogen concentrations. Nitrogen-bearing rocks are globally distributed and comprise a potentially large pool of nitrogen in nutrient cycling that is frequently neglected because of a lack of routine analytical methods for quantification. Nitrogen in rock originates as organically bound nitrogen associated with sediment, or in thermal waters representing a mixture of sedimentary, mantle, and meteoric sources of nitrogen. Rock nitrogen concentrations range from trace levels (>200 mg N kg -1) in granites to ecologically significant concentrations exceeding 1000 mg N kg -1 in some sedimentary and metasedimentary rocks. Nitrate deposits accumulated in arid and semi-arid regions are also a large potential pool. Nitrogen in rock has a potentially significant impact on localized nitrogen cycles. Elevated nitrogen concentrations in water and soil have been attributed to weathering of bedrock nitrogen. In some environments, nitrogen released from bedrock may contribute to nitrogen saturation of terrestrial ecosystems (more nitrogen available than required by biota). Nitrogen saturation results in leaching of nitrate to surface and groundwaters, and, where soils are formed from ammonium-rich bedrock, the oxidation of ammonium to nitrate may result in soil acidification, inhibiting revegetation in certain ecosystems. Collectively, studies presented in this article reveal that geologic nitrogen may be a large and reactive pool with potential for amplification of human impacts on nitrogen cycling in terrestrial and aquatic ecosystems.

  16. Interactive Effects of Nitrogen and Climate Change on Biodiversity

    Science.gov (United States)

    Porter, E. M.; Bowman, W. D.; Clark, C. M.; Compton, J. E.; Pardo, L. H.; Soong, J.

    2011-12-01

    Biodiversity has been described as the diversity of life on earth within species, between species and in ecosystems. Biodiversity contributes to regulating ecosystem services like climate, flood, disease, and water quality regulation. Biodiversity also supports and sustains ecosystem services that provide material goods like food, fiber, fuel, timber and water, and to non-material benefits like educational, recreational, spiritual, and aesthetic ecosystem services. The Millennium Ecosystem Assessment estimated that the rate of biodiversity loss due to human activity in the last 50 years has been more rapid than at any other time in human history, and that many of the drivers of biodiversity loss are increasing. The strongest drivers of biodiversity loss include habitat loss, overexploitation, invasive species, climate change, and pollution, including pollution from reactive nitrogen. Of these stressors, climate change and reactive nitrogen from anthropogenic activities are causing some of the most rapid changes. Climate change is causing warming trends that result in consistent patterns of poleward and elevational range shifts of flora and fauna, causing changes in biodiversity. Warming has also resulted in changes in phenology, particularly the earlier onset of spring events, migration, and lengthening of the growing season, disrupting predator-prey and plant-pollinator interactions. In addition to warming, elevated carbon dioxide by itself can affect biodiversity by influencing plant growth, soil water, tissue stoichiometry, and trophic interactions. Nitrogen enrichment also impacts ecosystems and biodiversity in a variety of ways. Nitrogen enhances plant growth, but has been shown to favor invasive, fast-growing species over native species adapted to low nitrogen conditions. Although there have been a limited number of empirical studies on climate change and nitrogen interactions, inferences can be drawn from observed responses to each stressor by itself. For

  17. Release of organic nitrogen compounds from Kerogen via catalytic hydropyrolysis

    Directory of Open Access Journals (Sweden)

    Bennett B

    2000-12-01

    Full Text Available High hydrogen pressure pyrolysis (hydropyrolysis was performed on samples of solvent extracted Kimmeridge Clay Formation source rock with a maturity equivalent to ca. 0.35% vitrinite reflectance. We describe the types and distributions of organic nitrogen compounds in the pyrolysis products (hydropyrolysates using GC-MS. Compounds identified included alkyl-substituted indoles, carbazoles, benzocarbazoles, quinolines and benzoquinolines. The distributions of the isomers of methylcarbazoles, C2-alkylcarbazoles and benzocarbazoles in the hydropyrolysates were compared to a typical North Sea oil. The hydropyrolysates compared to the North Sea oil, showed increased contributions from alkylcarbazole isomers where the nitrogen group is "exposed" (no alkyl substituents adjacent to the nitrogen functionality and appreciable levels of benzo[b]carbazole relative to benzo[a]- and benzo[c]carbazoles. Hydropyrolysis is found to be an ideal technique for liberating appreciable quantities of heterocyclic organic nitrogen compounds from geomacromolecules. The products released from the immature Kimmeridge Clay are thought to represent a potential source of nitrogen compounds in the bound phase (kerogen able to contribute to the free bitumen phase during catagenesis.

  18. High-nitrogen explosives

    Energy Technology Data Exchange (ETDEWEB)

    Naud, D. (Darren); Hiskey, M. A. (Michael A.); Kramer, J. F. (John F.); Bishop, R. L. (Robert L.); Harry, H. H. (Herbert H.); Son, S. F. (Steven F.); Sullivan, G. K. (Gregg K.)

    2002-01-01

    The syntheses and characterization of various tetrazine and furazan compounds offer a different approach to explosives development. Traditional explosives - such as TNT or RDX - rely on the oxidation of the carbon and hydrogen atoms by the oxygen carrying nitro group to produce the explosive energy. High-nitrogen compounds rely instead on large positive heats of formation for that energy. Some of these high-nitrogen compounds have been shown to be less sensitive to initiation (e.g. by impact) when compared to traditional nitro-containing explosives of similar performances. Using the precursor, 3,6-bis-(3,5-dimethylpyrazol-1-yl)-s-tetrazine (BDT), several useful energetic compounds based on the s-tetrazine system have been synthesized and studied. The compound, 3,3{prime}-azobis(6-amino-s-tetrazine) or DAAT, detonates as a half inch rate stick despite having no oxygen in the molecule. Using perfluoroacetic acid, DAAT can be oxidized to give mixtures of N-oxide isomers (DAAT03.5) with an average oxygen content of about 3.5. This energetic mixture burns at extremely high rates and with low dependency on pressure. Another tetrazine compound of interest is 3,6-diguanidino-s-tetrazine(DGT) and its dinitrate and diperchlorate salts. DGT is easily synthesized by reacting BDT with guanidine in methanol. Using Caro's acid, DGT can be further oxidized to give 3,6-diguanidino-s-tetrazine-1,4-di-N-oxide (DGT-DO). Like DGT, the di-N-oxide can react with nitric acid or perchloric acid to give the dinitrate and the diperchlorate salts. The compounds, 4,4{prime}-diamino-3,3{prime}-azoxyfurazan (DAAF) and 4,4{prime}-diamino-3,3{prime}-azofurazan (DAAzF), may have important future roles in insensitive explosive applications. Neither DAAF nor DAAzF can be initiated by laboratory impact drop tests, yet both have in some aspects better explosive performances than 1,3,5-triamino-2,4,6-trinitrobenzene TATB - the standard of insensitive high explosives. The thermal stability of DAAz

  19. Sequential, progressive, equal-power, reflective beam-splitter arrays

    Science.gov (United States)

    Manhart, Paul K.

    2017-11-01

    The equations to calculate equal-power reflectivity of a sequential series of beam splitters is presented. Non-sequential optical design examples are offered for uniform illumination using diode lasers. Objects created using Boolean operators and Swept Surfaces can create objects capable of reflecting light into predefined elevation and azimuth angles. Analysis of the illumination patterns for the array are also presented.

  20. Nitrogen system for the SSC

    International Nuclear Information System (INIS)

    McAshan, M.; Thirumaleshwar, M.; Abramovich, S.; Ganni, V.

    1992-10-01

    The Superconducting Super Collider consists of two parallel magnet rings, each 87,120 m in circumference, constructed in a tunnel 25 m to 74 m below ground level. They are operated at a controlled low helium temperature in order to maintain the magnet windings in the superconducting state. To obtain this condition, the magnet cryostat is designed with a high-quality insulation obtained by a high vacuum chamber, multilayer insulation, and thermal shields at nominal temperatures of 84 K and 20 K. Thermal radiation and the conduction heat load through the supports are intercepted and absorbed by the 84-K shield. Liquid nitrogen provides the refrigeration for these loads. The 84-K shield is anchored to two 63.5-mm stainless-steel tubes. One of the tubes, the ''liquid line,'' serves as a conduit in the distribution system of liquid nitrogen. The other tube, the ''vapor line,'' is used to collect the nitrogen vapor generated in the cooling process and to supply this vapor to,the helium refrigerators for precooling. The vapor line may also be used as a continuous cooler by injecting controlled amounts of liquid nitrogen. The nitrogen system consists of nitrogen supplies; ten nitrogen dewars for the collider and two for the High Energy Booster located on the ground at the main shaft entrances; liquid and vapor transfer lines through the shaft to connect the surface and the tunnel systems; and transfer lines to bypass warm equipment sections of the collider. The nitrogen system is expected to operate at steady state condition except for cooldown, warmup, and system repair, for which transients are expected. During normal operation and standby modes of the collider, temperature, pressure, and mass flow are expected to be constant in all circuits of the nitrogen system. The conceptual design requirements for various flow schemes and the engineering considerations are presented in this report

  1. Self-Reflection

    DEFF Research Database (Denmark)

    Fausing, Bent

    2018-01-01

    Reflecting has a double meaning, mirroring and thinking. The seminar will investigate how these two meanings intervene in each other. As we perceive we are already in pre-refectory state, and thinking involves a lot of not only thoughts, but also of senses and sensing, wherefrom our thoughts star...

  2. Worship, Reflection, Empirical Research

    OpenAIRE

    Ding Dong,

    2012-01-01

    In my youth, I was a worshipper of Mao Zedong. From the latter stage of the Mao Era to the early years of Reform and Opening, I began to reflect on Mao and the Communist Revolution he launched. In recent years I’ve devoted myself to empirical historical research on Mao, seeking the truth about Mao and China’s modern history.

  3. Wave Reflection Model Tests

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Larsen, Brian Juul

    The investigation concerns the design of a new internal breakwater in the main port of Ibiza. The objective of the model tests was in the first hand to optimize the cross section to make the wave reflection low enough to ensure that unacceptable wave agitation will not occur in the port. Secondly...

  4. Reflections on 21 years

    International Nuclear Information System (INIS)

    Eklund, S.; Mandel, H.; Teller, E.

    1977-01-01

    Personal reflections after twenty one years of nuclear power are presented by a number of those who were international figures in the nuclear energy field during that period. Lessons learnt, achievements, prospects and predictions for the future are discussed in eleven brief surveys. (U.K.)

  5. Reflection by Porro Prisms

    Science.gov (United States)

    Greenslade, Thomas B.

    2010-04-01

    Students all know that reflection from a plane mirror produces an image that is reversed right to left and so cannot be read by anyone but Leonardo da Vinci, who kept his notes in mirror writing. A useful counter-example is the Porro prism, which produces an image that is not reversed.

  6. Value reflected health education

    DEFF Research Database (Denmark)

    Wistoft, Karen; Nordentoft, Helle Merete

    2011-01-01

    This article examines the impact of a value-reflected approach in health education by demonstrating the nature of professional competence development connected to this approach. It is based on findings from two three-year health educational development projects carried out by school health nurses...... develop pedagogical competences in health education improving school childrens’ health....

  7. Reflection on Political Representation

    DEFF Research Database (Denmark)

    Kusche, Isabel

    2017-01-01

    This article compares how Members of Parliament in the United Kingdom and Ireland reflect on constituency service as an aspect of political representation. It differs from existing research on the constituency role of MPs in two regards. First, it approaches the question from a sociological viewp...

  8. Onward: Reflections on Mentoring

    Science.gov (United States)

    Williams, Kimberley Buster

    2018-01-01

    The author has been blessed with great mentors throughout her career. When she was invited to participate in the Leadership University of Mary Washington (UMW), a mentoring program at her institution, she did not hesitate to say yes. In this article, the author shares her reflections on mentoring.

  9. Interferometric reflection moire

    Science.gov (United States)

    Sciammarella, Cesar A.; Combell, Olivier

    1995-06-01

    A new reflection moire technique is introduced in this paper. The basic equations that relate the measurement of slopes to the basic geometric and optical parameters of the system are derived. The sensitivity and accuracy of the method are discussed. Examples of application to the study of silicon wafers and electronic chips are given.

  10. Reflection on robotic intelligence

    NARCIS (Netherlands)

    Bartneck, C.

    2006-01-01

    This paper reflects on the development or robots, both their physical shape as well as their intelligence. The later strongly depends on the progress made in the artificial intelligence (AI) community which does not yet provide the models and tools necessary to create intelligent robots. It is time

  11. Reflections on "La Esperanza"

    Science.gov (United States)

    Cortez, Anita

    2007-01-01

    The author was recently asked to reflect on her "educational journey." As far as she can remember she has been hungry to learn. A friend once described her as having "hambres atrasadas," which he described as a kind of "hunger nipping at her heels." It goes back, of course, to her parents: Her father's and her early…

  12. Reflecting on Writing Autobiography

    Science.gov (United States)

    Begg, Andy

    2011-01-01

    The following reflections relate to the reasons for and an approach to an autobiographic task, the notions that underpin it, and some thoughts about the quality and value of such a project. The focus was on the ways one views curriculum change over time; and the intention was to provide an example that others may sense as either familiar or at…

  13. Reflections on the Field.

    Science.gov (United States)

    Kauffman, James M.

    2003-01-01

    Reflections on the field of special education offer six ideas: (1) the value of science; (2) the continuing value of separate and special education for some students; (3) the continuing importance of prevention; (4) the importance of academic instruction; (5) the importance of social justice for the poor; and (6) a renewed emphasis on human…

  14. Reflections, 15 Years Later

    Science.gov (United States)

    Knox, George

    2016-01-01

    George Knox reflects on his 15-year career as president of Labette Community College in Parsons, Kansas. Knox writes that, as a first-time president coming into a brand new system, he was very fortunate to have many seasoned presidents and mentors in Kansas and from the American Association of Community Colleges' (AACC) Presidents Academy. He says…

  15. On nitrogen solubility in water

    International Nuclear Information System (INIS)

    Kalajda, Yu.A.; Katkov, Yu.D.; Kuznetsov, V.A.; Lastovtsev, A.Yu.; Lastochkin, A.P.; Susoev, V.S.

    1980-01-01

    Presented are the results of experimental investigations on nitrogen solubility in water under 0-15 MPa pressure, at the temperature of 100-340 deg C and nitrogen concentration of 0-5000 n.ml. N 2 /kg H 2 O. Empiric equations are derived and a diagram of nitrogen solubility in water is developed on the basis of the experimental data, as well as critically evaluated published data. The investigation results can be used in analyzing water-gas regime of a primary heat carrier in stream-generating plants with water-water reactors

  16. Automatic liquid nitrogen feeding device

    International Nuclear Information System (INIS)

    Gillardeau, J.; Bona, F.; Dejachy, G.

    1963-01-01

    An automatic liquid nitrogen feeding device has been developed (and used) in the framework of corrosion tests realized with constantly renewed uranium hexafluoride. The issue was to feed liquid nitrogen to a large capacity metallic trap in order to condensate uranium hexafluoride at the exit of the corrosion chambers. After having studied various available devices, a feeding device has been specifically designed to be robust, secure and autonomous, as well as ensuring a high liquid nitrogen flowrate and a highly elevated feeding frequency. The device, made of standard material, has been used during 4000 hours without any problem [fr

  17. Avian Incubation Patterns Reflect Temporal Changes in Developing Clutches.

    Directory of Open Access Journals (Sweden)

    Caren B Cooper

    Full Text Available Incubation conditions for eggs influence offspring quality and reproductive success. One way in which parents regulate brooding conditions is by balancing the thermal requirements of embryos with time spent away from the nest for self-maintenance. Age related changes in embryo thermal tolerance would thus be expected to shape parental incubation behavior. We use data from unmanipulated Black-capped Chickadee (Poecile atricapillus nests to examine the temporal dynamics of incubation, testing the prediction that increased heat flux from eggs as embryos age influences female incubation behavior and/or physiology to minimize temperature fluctuations. We found that the rate of heat loss from eggs increased with embryo age. Females responded to increased egg cooling rates by altering incubation rhythms (more frequent, shorter on- and off- bouts, but not brood patch temperature. Consequently, as embryos aged, females were able to increase mean egg temperature and decrease variation in temperature. Our findings highlight the need to view full incubation as more than a static rhythm; rather, it is a temporally dynamic and finely adjustable parental behavior. Furthermore, from a methodological perspective, intra- and inter-specific comparisons of incubation rhythms and average egg temperatures should control for the stage of incubation.

  18. Patterns of missionary expansion enterprise in Africa: a reflection ...

    African Journals Online (AJOL)

    ... most inspiring emotions supporting the historical missionary enterprise. Findings showed that the missionaries aroused national consciousness from negative and positive perspectives through missionary support for colonialism in Africa, missionary support of colonial aggression, the gospel values and mission education.

  19. Functional connectivity patterns reflect individual differences in conflict adaptation.

    Science.gov (United States)

    Wang, Xiangpeng; Wang, Ting; Chen, Zhencai; Hitchman, Glenn; Liu, Yijun; Chen, Antao

    2015-04-01

    Individuals differ in the ability to utilize previous conflict information to optimize current conflict resolution, which is termed the conflict adaptation effect. Previous studies have linked individual differences in conflict adaptation to distinct brain regions. However, the network-based neural mechanisms subserving the individual differences of the conflict adaptation effect have not been studied. The present study employed a psychophysiological interaction (PPI) analysis with a color-naming Stroop task to examine this issue. The main results were as follows: (1) the anterior cingulate cortex (ACC)-seeded PPI revealed the involvement of the salience network (SN) in conflict adaptation, while the posterior parietal cortex (PPC)-seeded PPI revealed the engagement of the central executive network (CEN). (2) Participants with high conflict adaptation effect showed higher intra-CEN connectivity and lower intra-SN connectivity; while those with low conflict adaptation effect showed higher intra-SN connectivity and lower intra-CEN connectivity. (3) The PPC-centered intra-CEN connectivity positively predicted the conflict adaptation effect; while the ACC-centered intra-SN connectivity had a negative correlation with this effect. In conclusion, our data demonstrated that conflict adaptation is likely supported by the CEN and the SN, providing a new perspective on studying individual differences in conflict adaptation on the basis of large-scale networks. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Specialization Patterns

    OpenAIRE

    Schultz , Ulrik Pagh; Lawall , Julia ,; Consel , Charles

    1999-01-01

    Design patterns offer numerous advantages for software development, but can introduce inefficiency into the finished program. Program specialization can eliminate such overheads, but is most effective when targeted by the user to specific bottlenecks. Consequently, we propose to consider program specialization and design patterns as complementary concepts. On the one hand, program specialization can optimize object-oriented programs written using design patterns. On the other hand, design pat...

  1. Prediction of future nitrogen loading to Lake Rotorua

    International Nuclear Information System (INIS)

    Morgenstern, U.; Gordon, D.

    2006-01-01

    loading estimate for the direct groundwater has the largest uncertainty because very limited age and chemistry data is available. Lake side springs and minor streams together contribute only about 5% of the total nitrogen load to Lake Rotorua. Hamurana, Awahou and Waingaehe streams are expected to show the largest increases in N loading in the future because they contain the oldest water, and Hamurana and Awahou streams will have the largest increase in nitrogen mass loading because they have the largest flow. Utuhina, Waiteti, and Puarenga streams are expected to have medium increases in nitrogen loading because of younger water age and lower flow. Ngongotaha, Waiohewa, and Waiowhiro streams are expected to have little further increase in N loading because of low flow or steady-state already reached. Landuse intensification that has occurred within the last 20 years is not yet reflected in the current nitrogen prediction model because information on the timing and amount of intensification was not yet available. The present nitrogen prediction model assumes that the nitrogen input in the catchment from landuse development has remained relatively constant since the 1950's. The current predictions would therefore represent a lower limit to which the more recent nitrogen loads would have to be added. If more information on timing and amount of landuse changes becomes available, the N load predictions can be refined to incorporate landuse change in several stages by calculating the predicted N load for each stage and adding these. Positive (intensification) or negative (retirement) changes can be considered. The large groundwater system of the Lake Rotorua catchment responds delayed by decades to landuse changes. These timeframes will need to be considered carefully for any possible mitigation options in the catchment. (author). 8 refs., 14 figs., 2 tabs

  2. Eastern oyster (Crassostrea virginica) δ15N as a bioindicator of nitrogen sources: Observations and modeling

    International Nuclear Information System (INIS)

    Fertig, B.; Carruthers, T.J.B.; Dennison, W.C.; Fertig, E.J.; Altabet, M.A.

    2010-01-01

    Stable nitrogen isotopes (δ 15 N) in bioindicators are increasingly employed to identify nitrogen sources in many ecosystems and biological characteristics of the eastern oyster (Crassostrea virginica) make it an appropriate species for this purpose. To assess nitrogen isotopic fractionation associated with assimilation and baseline variations in oyster mantle, gill, and muscle tissue δ 15 N, manipulative fieldwork in Chesapeake Bay and corresponding modeling exercises were conducted. This study (1) determined that five individuals represented an optimal sample size; (2) verified that δ 15 N in oysters from two locations converged after shared deployment to a new location reflecting a change in nitrogen sources; (3) identified required exposure time and temporal integration (four months for muscle, two to three months for gill and mantle); and (4) demonstrated seasonal δ 15 N increases in seston (summer) and oysters (winter). As bioindicators, oysters can be deployed for spatial interpolation of nitrogen sources, even in areas lacking extant populations.

  3. The reaction between barium and nitrogen in liquid sodium: resistivity studies

    International Nuclear Information System (INIS)

    Addison, C.C.; Creffield, G.K.; Hubberstey, P.; Pulham, R.J.

    1976-01-01

    The reaction of nitrogen with solutions of barium (between 0.34 and 6.89 mol % Ba) in liquid sodium at 573 K has been followed by changes in the electrical resistivity of the liquid. The capillary method has been employed, continuous sampling during reaction being achieved by electromagnetic pumping. The initial solution of nitrogen in the metal, followed by precipitation of barium and nitrogen from sodium as the nitride Ba 2 N, are reflected in the resistivity changes. The solubility of nitrogen in the alloy is a linear function of the barium concentration: S(mol % N) = x/4 (0 <= x <= 6.89 mol % Ba). This and the decrease in resistivity which invariably occurs during the solution process, provides additional information on the nature of solvation of nitrogen in solution in the liquid metal. (author)

  4. Pattern recognition

    CERN Document Server

    Theodoridis, Sergios

    2003-01-01

    Pattern recognition is a scientific discipline that is becoming increasingly important in the age of automation and information handling and retrieval. Patter Recognition, 2e covers the entire spectrum of pattern recognition applications, from image analysis to speech recognition and communications. This book presents cutting-edge material on neural networks, - a set of linked microprocessors that can form associations and uses pattern recognition to ""learn"" -and enhances student motivation by approaching pattern recognition from the designer's point of view. A direct result of more than 10

  5. Total Nitrogen in Surface Water

    Data.gov (United States)

    U.S. Environmental Protection Agency — Excess nitrogen in surface water can result in eutrophication. TOTALN is reported in kilograms/hectare/year. More information about these resources, including the...

  6. Being a reflective teacher——reflection on group management

    Institute of Scientific and Technical Information of China (English)

    Pan; Lehui

    2015-01-01

    <正>Introduction According to Pollard and Triggs(1997),reflective teaching is a process through which the capacity to make such professional judgments can be developed and maintained.Then what is a reflective teacher?Reflective teacher is someone who reflects systematically on her practice in a constant attempt to improve

  7. Ethical reflection and psychotherapy.

    Science.gov (United States)

    Vyskocilová, Jana; Prasko, Jan

    2013-01-01

    Theories of ethics and ethical reflection may be applied to both theory and practice in psychotherapy. There is a natural affinity between ethics and psychotherapy. Psychotherapy practice is concerned with human problems, dilemmas and emotions related to both one's own and other people's values. Ethics is also concerned with dilemmas in human thinking and with how these dilemmas reflect other individuals' values. Philosophical reflection itself is not a sufficient basis for the ethics of psychotherapy but it may aid in exploring attitudes related to psychotherapy, psychiatry and health care. PubMed, Web of Science and Scopus databases were searched for articles containing the keywords "psychotherapy", "ethics", "therapeutic relationship" and "supervision". The search was conducted by repeating the terms in various combinations without language or time restrictions. Also included were data from monographs cited in reviews. The resulting text is a review with conclusions concerning ethical aspects of psychotherapy. The ability to behave altruistically, sense for justice and reciprocity and mutual help are likely to be genetically determined as dispositions to be later developed by upbringing or to be formed or deformed by upbringing. Early experiences lead to formation of ethical attitudes which are internalized and then applied to both one's own and other people's behavior. Altruistic behavior has a strong impact on an individual's health and its acceptance may positively influence the pathophysiological mechanisms underlying numerous diseases. Ethical theory and reflection, however, may be applied to both theory and practice of psychotherapy in a conscious, targeted and thoughtful manner. In everyday practice, psychotherapists and organizations must necessarily deal with conscious conflicts between therapeutic possibilities, clients' wishes, their own as well as clients' ideas and the real world. Understanding one's own motives in therapy is one of the aims of a

  8. The nitrogen cycle on Mars

    Science.gov (United States)

    Mancinelli, Rocco L.

    1989-01-01

    Nirtogen is an essential element for the evolution of life, because it is found in a variety of biologically important molecules. Therefore, N is an important element to study from a exobiological perspective. In particular, fixed nitrogen is the biologically useful form of nitrogen. Fixed nitrogen is generally defines as NH3, NH4(+), NO(x), or N that is chemically bound to either inorganic or organic molecules, and releasable by hydrolysis to NH3 or NH4(+). On Earth, the vast majority of nitrogen exists as N2 in the atmosphere, and not in the fixes form. On early Mars the same situations probably existed. The partial pressure of N2 on early Mars was thought to be 18 mb, significantly less than that of Earth. Dinitrogen can be fixed abiotically by several mechanisms. These mechanisms include thernal shock from meteoritic infall and lightning, as well as the interaction of light and sand containing TiO2 which produces NH3 that would be rapidly destroyed by photolysis and reaction with OH radicals. These mechanisms could have been operative on primitive Mars.The chemical processes effecting these compounds and possible ways of fixing or burying N in the Martian environment are described. Data gathered in this laboratory suggest that the low abundance of nitrogen along (compared to primitive Earth) may not significantly deter the origin and early evolution of a nitrogen utilizing organisms. However, the conditions on current Mars with respect to nitrogen are quite different, and organisms may not be able to utilize all of the available nitrogen.

  9. Enhanced nitrogen deposition over China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xuejun; Zhang, Ying; Han, Wenxuan; Tang, Aohan; Shen, Jianlin; Cui, Zhenling; Christie, Peter; Zhang, Fusuo [College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China); Vitousek, Peter [Department of Biology, Stanford University, Stanford, California 94305 (United States); Erisman, Jan Willem [VU University Amsterdam, 1081 HV Amsterdam (Netherlands); Goulding, Keith [The Sustainable Soils and Grassland Systems Department, Rothamsted Research, Harpenden AL5 2JQ (United Kingdom); Fangmeier, Andreas [Institute of Landscape and Plant Ecology, University of Hohenheim, 70593 Stuttgart (Germany)

    2013-02-28

    China is experiencing intense air pollution caused in large part by anthropogenic emissions of reactive nitrogen. These emissions result in the deposition of atmospheric nitrogen (N) in terrestrial and aquatic ecosystems, with implications for human and ecosystem health, greenhouse gas balances and biological diversity. However, information on the magnitude and environmental impact of N deposition in China is limited. Here we use nationwide data sets on bulk N deposition, plant foliar N and crop N uptake (from long-term unfertilized soils) to evaluate N deposition dynamics and their effect on ecosystems across China between 1980 and 2010. We find that the average annual bulk deposition of N increased by approximately 8 kilograms of nitrogen per hectare (P < 0.001) between the 1980s (13.2 kilograms of nitrogen per hectare) and the 2000s (21.1 kilograms of nitrogen per hectare). Nitrogen deposition rates in the industrialized and agriculturally intensified regions of China are as high as the peak levels of deposition in northwestern Europe in the 1980s, before the introduction of mitigation measures. Nitrogen from ammonium (NH4+) is the dominant form of N in bulk deposition, but the rate of increase is largest for deposition of N from nitrate (NO3-), in agreement with decreased ratios of NH3 to NOx emissions since 1980. We also find that the impact of N deposition on Chinese ecosystems includes significantly increased plant foliar N concentrations in natural and semi-natural (that is, non-agricultural) ecosystems and increased crop N uptake from long-term-unfertilized croplands. China and other economies are facing a continuing challenge to reduce emissions of reactive nitrogen, N deposition and their negative effects on human health and the environment.

  10. International food trade reduces environmental effects of nitrogen pollution in China.

    Science.gov (United States)

    Shi, Yaxing; Wu, Shaohua; Zhou, Shenglu; Wang, Chunhui; Chen, Hao

    2016-09-01

    The globalization of agricultural trade has dramatically altered global nitrogen flows by changing the spatial pattern of nitrogen utilization and emissions at a global scale. As a major trading country, China uses a large amount of nitrogen, which has a profound impact on global nitrogen flows. Using data on food production and trade between China and 26 other countries and regions, we calculated nitrogen inputs and outputs in food production ecosystem in each country. We estimated nitrogen flows in international food trade and analyzed their impact on nitrogen pollution in China. We divided nitrogen flows into embodied and virtual nitrogen flows. Embodied nitrogen is taken up by the plant and incorporated into the final food product, whereas virtual nitrogen is lost to the environment throughout the food production process and is not contained in the final food product. Our results show that China mainly imports food products from America and Asia, accounting for 95 % of all imported food. Asia (mainly Japan) and Europe are the main exporters of food from China, with Japan and the EU accounting for 17 and 10 % of all exported food, respectively. Total nitrogen inputs and outputs in food production in China were 55,400 and 61,000 Gg respectively, which were much higher than in other countries. About 1440 and 950 Gg of embodied and virtual nitrogen respectively flow into China through the food trade, mainly from food-exporting countries such as the USA, Argentina, and Brazil. Meanwhile, 177 and 160 Gg of embodied and virtual nitrogen respectively flow out of China from the export of food products, mainly to Japan. China's net food imports have reduced 720 and 458 Gg for nitrogen utilization and outputs, respectively, which accounted for 1.3 and 0.78 % of total nitrogen inputs and outputs in China. These results suggest that food trade in China has a profound effect on nitrogen flows and has greatly reduced environmental impacts on nitrogen pollution in China.

  11. 长江口外海域沉积物中有机物的来源及分布%Spatial distributions of organic carbon and nitrogen and their isotopic compositions in sediments of the Changjiang Estuary and its adjacent sea area

    Institute of Scientific and Technical Information of China (English)

    高建华; 汪亚平; 潘少明; 张瑞; 李军; 白风龙

    2008-01-01

    The spatial distribution patterns of total organic carbon and total nitrogen show significant correlations with currents of the East China Sea Shelf. Corresponding to distributions of these currents, the study area could be divided into four different parts. Total organic carbon, total nitrogen, and organic carbon and nitrogen stable isotopes in sediments show linear correlations with mean grain size, respectively, thus "grain size effect" is an important factor that influences their distributions. C/N ratios can reflect source information of organic matter to a certain degree. In contrast, nitrogen stable isotope shows different spatial distribution patterns with C/N and organic carbon stable isotope, according to their relationships and regional distributions. The highest contribution (up to 50%) of terrestrial organic carbon appears near the Changjiang Estuary with isolines projecting towards northeast, indicating the influence of the Changjiang dilution water. Terrestrial particulate organic matter suffers from effects of diagenesis, benthos and incessant inputting of dead organic matter of plankton,after depositing in seabed. Therefore, the contribution of terrestrial organic carbon to particulate organic matter is obviously greater than that to organic matter in sediments in the same place.

  12. Biogeochemistry and nitrogen cycling in an Arctic, volcanic ecosystem

    Science.gov (United States)

    Fogel, M. L.; Benning, L.; Conrad, P. G.; Eigenbrode, J.; Starke, V.

    2007-12-01

    As part of a study on Mars Analogue environments, the biogeochemistry of Sverrefjellet Volcano, Bocfjorden, Svalbard, was conducted and compared to surrounding glacial, thermal spring, and sedimentary environments. An understanding of how nitrogen might be distributed in a landscape that had extinct or very cold adapted, slow- growing extant organisms should be useful for detecting unknown life forms. From high elevations (900 m) to the base of the volcano (sea level), soil and rock ammonium concentrations were uniformly low, typically less than 1- 3 micrograms per gm of rock or soil. In weathered volcanic soils, reduced nitrogen concentrations were higher, and oxidized nitrogen concentrations lower. The opposite was found in a weathered Devonian sedimentary soil. Plants and lichens growing on volcanic soils have an unusually wide range in N isotopic compositions from -5 to +12‰, a range rarely measured in temperate ecosystems. Nitrogen contents and isotopic compositions of volcanic soils and rocks were strongly influenced by the presence or absence of terrestrial herbivores or marine avifauna with higher concentrations of N and elevated N isotopic compositions occurring as patches in areas immediately influenced by reindeer, Arctic fox ( Alopex lagopus), and marine birds. Because of the extreme conditions in this area, ephemeral deposition of herbivore feces results in a direct and immediate N pulses into the ecosystem. The lateral extent and distribution of marine- derived nitrogen was measured on a landscape scale surrounding an active fox den. Nitrogen was tracked from the bones of marine birds to soil to vegetation. Because of extreme cold, slow biological rates and nitrogen cycling, a mosaic of N patterns develops on the landscape scale.

  13. Anaerobic Nitrogen Fixers on Mars

    Science.gov (United States)

    Lewis, B. G.

    2000-07-01

    The conversion of atmospheric nitrogen gas to the protein of living systems is an amazing process of nature. The first step in the process is biological nitrogen fixation, the transformation of N2 to NH3. The phenomenon is crucial for feeding the billions of our species on Earth. On Mars, the same process may allow us to discover how life can adapt to a hostile environment, and render it habitable. Hostile environments also exist on Earth. For example, nothing grows in coal refuse piles due to the oxidation of pyrite and marcasite to sulfuric acid. Yet, when the acidity is neutralized, alfalfa and soybean plants develop root nodules typical of symbiotic nitrogen fixation with Rhizobium species possibly living in the pyritic material. When split open, these nodules exhibited the pinkish color of leghemoglobin, a protein in the nodule protecting the active nitrogen-fixing enzyme nitrogenase against the toxic effects of oxygen. Although we have not yet obtained direct evidence of nitrogenase activity in these nodules (reduction of acetylene to ethylene, for example), these findings suggested the possibility that nitrogen fixation was taking place in this hostile, non-soil material. This immediately raises the possibility that freeliving anaerobic bacteria which fix atmospheric nitrogen on Earth, could do the same on Mars.

  14. Odd nitrogen production by meteoroids

    Science.gov (United States)

    Park, C.; Menees, G. P.

    1978-01-01

    The process by which odd nitrogen species (atomic nitrogen and nitric oxide) are formed during atmospheric entry of meteoroids is analyzed theoretically. An ablating meteoroid is assumed to be a point source of mass with a continuum regime evolving in its wake. The amounts of odd nitrogen species, produced by high-temperature reactions of air in the continuum wake, are calculated by numerical integration of chemical rate equations. Flow properties are assumed to be uniform across the wake, and 29 reactions involving five neutral species and five singly ionized species are considered, as well as vibrational and electron temperature nonequilibrium phenomena. The results, when they are summed over the observed mass, velocity, and entry-angle distribution of meteoroids, provide odd-nitrogen-species annual global production rates as functions of altitude. The peak production of nitric oxide is found to occur at an altitude of about 85 km; atomic nitrogen production peaks at about 95 km. The total annual rate for nitric oxide is 40 million kg; for atomic nitrogen it is 170 million kg.

  15. Bragg reflection program

    International Nuclear Information System (INIS)

    Lynn, J.W.

    This user's guide to the Bragg Reflection Program (BRP) is in the nature of an informal report. The general purpose of BRP is to scan a series of Bragg reflections automatically in order to obtain profiles and integrated intensities. The program is used in conjunction with the SUPERVISOR and READ packages, and the procedures for using it are similar to those for the Triple-Axis Control program. All the general features of the system, SUPERVISOR and READ packages as described in the Spectrometer Control Systems User's Guide are preserved. The presentation assumes that the reader is familiar with these. Sections are given on the READ package, execution and use, error messages, and output. A few sample problems are shown. (1 figure) (U.S.)

  16. Reflections on Active Networking

    Science.gov (United States)

    2005-01-01

    with a Software Switch for Active Networks ”. We had initially called the project “ SoftSwitch ”, but after some concerns David Farber raised that this...Reflections on Active Networking Jonathan M. Smith CIS Department, University of Pennsylvania jms@cis.upenn.edu Abstract Interactions among...telecommunications networks , computers, and other peripheral devices have been of interest since the earliest distributed computing systems. A key

  17. Clinical linguistics: conversational reflections.

    Science.gov (United States)

    Crystal, David

    2013-04-01

    This is a report of the main points I made in an informal "conversation" with Paul Fletcher and the audience at the 14th ICPLA conference in Cork. The observations arose randomly, as part of an unstructured 1-h Q&A, so they do not provide a systematic account of the subject, but simply reflect the issues which were raised by the conference participants during that time.

  18. Superradiance or total reflection?

    CERN Document Server

    László, András

    2014-01-01

    Numerical evolution of massless scalar fields on Kerr background is studied. The initial data specifications are chosen to have compact support separated from the ergoregion and to yield nearly monochromatic incident wave packets. The initial data is also tuned to maximize the effect of superradiance. Evidences are shown indicating that instead of the anticipated energy extraction from black hole the incident radiation fail to reach the ergoregion rather it suffers a nearly perfect reflection.

  19. Reflection-type electromagnetically induced transparency analogue in terahertz metamaterials

    International Nuclear Information System (INIS)

    Ding Chun-Feng; Zhang Ya-Ting; Yao Jian-Quan; Xu De-Gang; Zhang Gui-Zhong; Sun Chong-Ling

    2014-01-01

    A reflection-type electromagnetically induced transparency (EIT) metamaterial is proposed, which is composed of a dielectric spacer sandwiched with metallic patterns and metallic plane. Experimental results of THz time domain spectrum (THz-TDS) exhibit a typical reflection of EIT at 0.865 THz, which are in excellent agreement with the full-wave simulations. A multi-reflection theory is adopted to analyze the physical mechanism of the reflection-type EIT, showing that the reflection-type EIT is a superposition of multiple reflection of the transmission EIT. Such a reflection-type EIT provides many applications based on the EIT effect, such as slow light devices and nonlinear elements. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  20. Revised models of interstellar nitrogen isotopic fractionation

    Science.gov (United States)

    Wirström, E. S.; Charnley, S. B.

    2018-03-01

    Nitrogen-bearing molecules in cold molecular clouds exhibit a range of isotopic fractionation ratios and these molecules may be the precursors of 15N enrichments found in comets and meteorites. Chemical model calculations indicate that atom-molecular ion and ion-molecule reactions could account for most of the fractionation patterns observed. However, recent quantum-chemical computations demonstrate that several of the key processes are unlikely to occur in dense clouds. Related model calculations of dense cloud chemistry show that the revised 15N enrichments fail to match observed values. We have investigated the effects of these reaction rate modifications on the chemical model of Wirström et al. (2012) for which there are significant physical and chemical differences with respect to other models. We have included 15N fractionation of CN in neutral-neutral reactions and also updated rate coefficients for key reactions in the nitrogen chemistry. We find that the revised fractionation rates have the effect of suppressing 15N enrichment in ammonia at all times, while the depletion is even more pronounced, reaching 14N/15N ratios of >2000. Taking the updated nitrogen chemistry into account, no significant enrichment occurs in HCN or HNC, contrary to observational evidence in dark clouds and comets, although the 14N/15N ratio can still be below 100 in CN itself. However, such low CN abundances are predicted that the updated model falls short of explaining the bulk 15N enhancements observed in primitive materials. It is clear that alternative fractionating reactions are necessary to reproduce observations, so further laboratory and theoretical studies are urgently needed.

  1. Polarizer reflectivity variations

    International Nuclear Information System (INIS)

    Ozarski, R.G.; Prior, J.

    1980-01-01

    On Shiva the beam energy along the chain is monitored using available reflections and/or transmission through beam steering, splitting, and polarizing optics without the intrusion of any additional glass for diagnostics. On the preamp table the diagnostic signal is obtained from the signal transmitted through turning mirrors. At the input of each chain the signal is obtained from the transmission through one of the mirrors used for the chain input alignment sensor (CHIP). At the chain output the transmission through the final turning mirror is used. These diagnostics have proved stable and reliable. However, one of the prime diagnostic locations is at the output of the beta rod. The energy at this location is measured by collecting small reflections from the last polarizer surface of the beta Pockels cell polarizer package. Unfortunately, calibration of this diagnostic has varied randomly, seldom remaining stable for a week or more. The cause of this fluctuation has been investigated for the past year and'it has been discovered that polarizer reflectivity varies with humidity. This report will deal with the possible causes that were investigated, the evidence that humidity is causing the variation, and the associated mechanism

  2. Nitrogen balance during growth of cauliflower

    NARCIS (Netherlands)

    Everaarts, A.P.

    2000-01-01

    The potential for loss of nitrogen to the environment during growth of cauliflower was investigated. A comparison was made between cauliflower growth and nitrogen uptake without, and with, nitrogen application of the recommended amount (=225 kg ha-1 minus mineral nitrogen in the soil layer 0–60 cm,

  3. Geodesic patterns

    KAUST Repository

    Pottmann, Helmut; Huang, Qixing; Deng, Bailin; Schiftner, Alexander; Kilian, Martin; Guibas, Leonidas J.; Wallner, Johannes

    2010-01-01

    Geodesic curves in surfaces are not only minimizers of distance, but they are also the curves of zero geodesic (sideways) curvature. It turns out that this property makes patterns of geodesics the basic geometric entity when dealing with the cladding of a freeform surface with wooden panels which do not bend sideways. Likewise a geodesic is the favored shape of timber support elements in freeform architecture, for reasons of manufacturing and statics. Both problem areas are fundamental in freeform architecture, but so far only experimental solutions have been available. This paper provides a systematic treatment and shows how to design geodesic patterns in different ways: The evolution of geodesic curves is good for local studies and simple patterns; the level set formulation can deal with the global layout of multiple patterns of geodesics; finally geodesic vector fields allow us to interactively model geodesic patterns and perform surface segmentation into panelizable parts. © 2010 ACM.

  4. Foam patterns

    Science.gov (United States)

    Chaudhry, Anil R; Dzugan, Robert; Harrington, Richard M; Neece, Faurice D; Singh, Nipendra P; Westendorf, Travis

    2013-11-26

    A method of creating a foam pattern comprises mixing a polyol component and an isocyanate component to form a liquid mixture. The method further comprises placing a temporary core having a shape corresponding to a desired internal feature in a cavity of a mold and inserting the mixture into the cavity of the mold so that the mixture surrounds a portion of the temporary core. The method optionally further comprises using supporting pins made of foam to support the core in the mold cavity, with such pins becoming integral part of the pattern material simplifying subsequent processing. The method further comprises waiting for a predetermined time sufficient for a reaction from the mixture to form a foam pattern structure corresponding to the cavity of the mold, wherein the foam pattern structure encloses a portion of the temporary core and removing the temporary core from the pattern independent of chemical leaching.

  5. Geodesic patterns

    KAUST Repository

    Pottmann, Helmut

    2010-07-26

    Geodesic curves in surfaces are not only minimizers of distance, but they are also the curves of zero geodesic (sideways) curvature. It turns out that this property makes patterns of geodesics the basic geometric entity when dealing with the cladding of a freeform surface with wooden panels which do not bend sideways. Likewise a geodesic is the favored shape of timber support elements in freeform architecture, for reasons of manufacturing and statics. Both problem areas are fundamental in freeform architecture, but so far only experimental solutions have been available. This paper provides a systematic treatment and shows how to design geodesic patterns in different ways: The evolution of geodesic curves is good for local studies and simple patterns; the level set formulation can deal with the global layout of multiple patterns of geodesics; finally geodesic vector fields allow us to interactively model geodesic patterns and perform surface segmentation into panelizable parts. © 2010 ACM.

  6. Reflection Revisited: The Class Collage

    Science.gov (United States)

    Sommers, Jeff

    2011-01-01

    Through the regular use of what Donald Schon has termed reflection-in-action and reflection-on-action, students can learn to improve their "reflection-in-presentation," in Kathleen Blake Yancey's term. Students are often asked to do this type of reflection-in-presentation as a capstone to first-year or basic writing courses. However, a number of…

  7. Reflection as Self-Assessment

    Science.gov (United States)

    Pappas, Marjorie L.

    2010-01-01

    In this article, the author discusses how reflection can be used as self-assessment. Reflection involves not only thinking about a learning experience, but also questioning parts of the experience. Reflection is thinking about what one knows from the learning experience, what one might do differently the next time. Reflection is wondering about…

  8. δ 15N Studies of Nitrogen Use by the Red Mangrove, Rhizophora mangle L. in South Florida

    Science.gov (United States)

    Fry, B.; Bern, A. L.; Ross, M. S.; Meeder, J. F.

    2000-02-01

    To help define nitrogen (N) sources and patterns of N processing in mangrove ecosystems, mangrove leaf nitrogen contents and δ 15N values were assayed in three marshes along the south Florida coast. In each marsh, leaf samples were collected from dwarf mangroves at interior locations and taller mangroves at the ocean fringe. Leaf % N and δ 15N values did not differ consistently between dwarf and tall mangroves, even though there were large variations in δ 15N (18‰ range, -5 to +13‰) and % N (1·2% range, 0·9-2·1%). Highest % N and δ 15N values occurred along the western margin of Biscayne Bay where canals draining agricultural lands deliver high-nitrate waters to fringing mangrove marshes. High mangrove δ 15N values may be good biomonitors of anthropogenic N loading to south Florida estuaries. Lower values likely reflect less anthropogenic N entering the mangrove marshes, as well as differences in plant physiology that occur along the fringe-dwarf gradient.

  9. Remote sensing techniques to monitor nitrogen-driven carbon dynamics in field corn

    Science.gov (United States)

    Corp, Lawrence A.; Middleton, Elizabeth M.; Campbell, Petya K. E.; Huemmrich, K. Fred; Cheng, Yen-Ben; Daughtry, Craig S. T.

    2009-08-01

    Patterns of change in vegetation growth and condition are one of the primary indicators of the present and future ecological status of the globe. Nitrogen (N) is involved in photochemical processes and is one of the primary resources regulating plant growth. As a result, biological carbon (C) sequestration is driven by N availability. Large scale monitoring of photosynthetic processes are currently possible only with remote sensing systems that rely heavily on passive reflectance (R) information. Unlike R, fluorescence (F) emitted from chlorophyll is directly related to photochemical reactions and has been extensively used for the elucidation of the photosynthetic pathways. Recent advances in passive fluorescence instrumentation have made the remote acquisition of solar-induced fluorescence possible. The goal of this effort is to evaluate existing reflectance and emerging fluorescence methodologies for determining vegetation parameters related to photosynthetic function and carbon sequestration dynamics in plants. Field corn N treatment levels of 280, 140, 70, and 0 kg N / ha were sampled from an intensive test site for a multi-disciplinary project, Optimizing Production Inputs for Economic and Environmental Enhancement (OPE). Aircraft, near-ground, and leaf-level measurements were used to compare and contrast treatment effects within this experiment site assessed with both reflectance and fluorescence approaches. A number of spectral indices including the R derivative index D730/D705, the normalized difference of R750 vs. R705, and simple ratio R800/R750 differentiated three of the four N fertilization rates and yielded high correlations to three important carbon parameters: C:N, light use efficiency, and grain yield. These results advocate the application of hyperspectral sensors for remotely monitoring carbon cycle dynamics in terrestrial ecosystems.

  10. Carbon-nitrogen interactions and biomass partitioning of Carex rostrata grown at three levels of nitrogen supply

    Energy Technology Data Exchange (ETDEWEB)

    Saarinen, T [Helsinki Univ. (Finland). Dept. of Ecology and Systematics

    1997-12-31

    Biomass and production of vascular plants constitutes a major source of carbon input in peatlands. As rates of decomposition vary considerably with depth, the vertical distribution of biomass may substantially affect accumulation of carbon in peatlands. Therefore, allocation patterns between shoot and roots are particularly important when considering carbon balance of peatland ecosystems. The stimulatory effect of increasing atmospheric concentration of CO{sub 2} or photosynthesis may increase availability of carbon to most C3 plants. Availability of nitrogen may also alter both due to increased atmospheric deposition and changer in mineralisation rates associated with climate change. Most root-shoot partitioning models predict that allocation of biomass is dependent of the availability and uptake of carbon and nitrogen. A decrease in supply of carbon would favour allocation to shoots and a decrease in supply of nitrogen would increase allocation to roots. At a cellular level, non structural carbohydrates and free amino acids are thought to represent the biochemically available fraction of carbon and nitrogen, respectively. The aim of this work is study the long-term growth responses of Carex rostrata to changes in the availability of nitrogen. Special attention is paid to soluble sugars ant free amino acids, which may control partitioning of biomass. (10 refs.)

  11. Carbon-nitrogen interactions and biomass partitioning of Carex rostrata grown at three levels of nitrogen supply

    Energy Technology Data Exchange (ETDEWEB)

    Saarinen, T. [Helsinki Univ. (Finland). Dept. of Ecology and Systematics

    1996-12-31

    Biomass and production of vascular plants constitutes a major source of carbon input in peatlands. As rates of decomposition vary considerably with depth, the vertical distribution of biomass may substantially affect accumulation of carbon in peatlands. Therefore, allocation patterns between shoot and roots are particularly important when considering carbon balance of peatland ecosystems. The stimulatory effect of increasing atmospheric concentration of CO{sub 2} or photosynthesis may increase availability of carbon to most C3 plants. Availability of nitrogen may also alter both due to increased atmospheric deposition and changer in mineralisation rates associated with climate change. Most root-shoot partitioning models predict that allocation of biomass is dependent of the availability and uptake of carbon and nitrogen. A decrease in supply of carbon would favour allocation to shoots and a decrease in supply of nitrogen would increase allocation to roots. At a cellular level, non structural carbohydrates and free amino acids are thought to represent the biochemically available fraction of carbon and nitrogen, respectively. The aim of this work is study the long-term growth responses of Carex rostrata to changes in the availability of nitrogen. Special attention is paid to soluble sugars ant free amino acids, which may control partitioning of biomass. (10 refs.)

  12. Nitrogen nutrition effects on development, growth and nitrogen accumulation of vegetables

    NARCIS (Netherlands)

    Biemond, H.

    1995-01-01

    In order to be able to match nitrogen supply and nitrogen requirement of vegetable crops, insight is necessary in the responses to nitrogen of important processes of growth and development. This study focused on effects of amount of nitrogen applied and fractionation of nitrogen supply on

  13. The Effect of Percentage of Nitrogen in Plasma Gas on Nitrogen ...

    African Journals Online (AJOL)

    Increase in nitrogen percent in the plasma gas results in increased content of dissociated nitrogen and molecular nitrogen possessing excess vibrational energy and therefore the increased solution of nitrogen in the liquid iron. It would appear that above 35% nitrogen in the plasma gas, frequency of collisions of species in ...

  14. [Assimilation of biological nitrogen by European beaver].

    Science.gov (United States)

    Vecherskiĭ, M V; Naumova, E I; Kostina, N V; Umarov, M M

    2009-01-01

    Nitrogenase activity, the abundance of diazotrophic bacteria, the structure and functional characteristics of the complex of microorganisms, and the content of nitrogen and carbon were determined in the contents of the gastrointestinal tract of the European beaver. A high nitrogen-fixing activity in the large intestine correlated with an increase in nitrogen content in the chyme upon its transfer over the gastrointestinal tract. It is assumed that microbial nitrogen fixation plays a major role in nitrogen nutrition of the European beaver.

  15. Nitrogen Compounds in Radiation Chemistry

    International Nuclear Information System (INIS)

    Sims, H.E.; Dey, G.R.; Vaudey, C.E.; Peaucelle, C.; Boucher, J.L.; Toulhoat, N.; Bererd, N.; Koppenol, W.H.; Janata, E.; Dauvois, V.; Durand, D.; Legand, S.; Roujou, J.L.; Doizi, D.; Dannoux, A.; Lamouroux, C.

    2009-01-01

    Water radiolysis in presence of N 2 is probably the topic the most controversy in the field of water radiolysis. It still exists a strong discrepancy between the different reports of ammonia formation by water radiolysis in presence of N 2 and moreover in absence of oxygen there is no agreement on the formation or not of nitrogen oxide like NO 2 - and NO 3 -. These discrepancies come from multiple sources: - the complexity of the reaction mechanisms where nitrogen is involved - the experimental difficulties - and, the irradiation conditions. The aim of the workshop is to capitalize the knowledge needed to go further in simulations and understanding the problems caused (or not) by the presence of nitrogen / water in the environment of radioactive materials. Implications are evident in terms of corrosion, understanding of biological systems and atmospheric chemistry under radiation. Topics covered include experimental and theoretical approaches, application and fundamental researches: - Nitrate and Ammonia in radiation chemistry in nuclear cycle; - NOx in biological systems and atmospheric chemistry; - Formation of Nitrogen compounds in Nuclear installations; - Nitrogen in future power plant projects (Gen4, ITER...) and large particle accelerators. This document gathers the transparencies available for 7 of the presentations given at this workshop. These are: - H.E SIMS: 'Radiation Chemistry of Nitrogen Compounds in Nuclear Power Plant'; - G.R. DEY: 'Nitrogen Compounds Formation in the Radiolysis of Aqueous Solutions'; - C.E. VAUDEY et al.: 'Radiolytic corrosion of nuclear graphite studied with the dedicated gas irradiation cell of IPNL'; - J.L. BOUCHER: 'Roles and biosynthesis of NO in eukaryotes and prokaryotes'; - W.H. KOPPENOL: 'Chemistry of NOx'; - E. JANATA: 'Yield of OH in N 2 O saturated aqueous solution'; - V. DAUVOIS: 'Analytical strategy for the study of radiolysis gases'

  16. Portable reflection for C++ with the Mirror library

    Directory of Open Access Journals (Sweden)

    Matus Chochlik

    2012-06-01

    Full Text Available Reflection and reflective programming can be used for a wide range of tasks such as implementationof serialization-like operations, remote procedure calls, scripting, automated GUIgeneration,implementation of several software design patterns, etc. C++ as one of the mostprevalent programming languages however, for various reasons, lacks a standardized reflectionfacility. In this paper we present Mirror - a portable library adding reflection to C++ with acommand-line utility automating its usage. This library supports functional style static compiletimereflection and metaprogramming and also provides two different object-oriented run-timepolymorphic layers for dynamic reflection.

  17. Seismic reflection imaging, accounting for primary and multiple reflections

    Science.gov (United States)

    Wapenaar, Kees; van der Neut, Joost; Thorbecke, Jan; Broggini, Filippo; Slob, Evert; Snieder, Roel

    2015-04-01

    Imaging of seismic reflection data is usually based on the assumption that the seismic response consists of primary reflections only. Multiple reflections, i.e. waves that have reflected more than once, are treated as primaries and are imaged at wrong positions. There are two classes of multiple reflections, which we will call surface-related multiples and internal multiples. Surface-related multiples are those multiples that contain at least one reflection at the earth's surface, whereas internal multiples consist of waves that have reflected only at subsurface interfaces. Surface-related multiples are the strongest, but also relatively easy to deal with because the reflecting boundary (the earth's surface) is known. Internal multiples constitute a much more difficult problem for seismic imaging, because the positions and properties of the reflecting interfaces are not known. We are developing reflection imaging methodology which deals with internal multiples. Starting with the Marchenko equation for 1D inverse scattering problems, we derived 3D Marchenko-type equations, which relate reflection data at the surface to Green's functions between virtual sources anywhere in the subsurface and receivers at the surface. Based on these equations, we derived an iterative scheme by which these Green's functions can be retrieved from the reflection data at the surface. This iterative scheme requires an estimate of the direct wave of the Green's functions in a background medium. Note that this is precisely the same information that is also required by standard reflection imaging schemes. However, unlike in standard imaging, our iterative Marchenko scheme retrieves the multiple reflections of the Green's functions from the reflection data at the surface. For this, no knowledge of the positions and properties of the reflecting interfaces is required. Once the full Green's functions are retrieved, reflection imaging can be carried out by which the primaries and multiples are

  18. Litter quality mediated nitrogen effect on plant litter decomposition regardless of soil fauna presence.

    Science.gov (United States)

    Zhang, Weidong; Chao, Lin; Yang, Qingpeng; Wang, Qingkui; Fang, Yunting; Wang, Silong

    2016-10-01

    Nitrogen addition has been shown to affect plant litter decomposition in terrestrial ecosystems. The way that nitrogen deposition impacts the relationship between plant litter decomposition and altered soil nitrogen availability is unclear, however. This study examined 18 co-occurring litter types in a subtropical forest in China in terms of their decomposition (1 yr of exposure in the field) with nitrogen addition treatment (0, 0.4, 1.6, and 4.0 mol·N·m -2 ·yr -1 ) and soil fauna exclusion (litter bags with 0.1 and 2 cm mesh size). Results showed that the plant litter decomposition rate is significantly reduced because of nitrogen addition; the strength of the nitrogen addition effect is closely related to the nitrogen addition levels. Plant litters with diverse quality responded to nitrogen addition differently. When soil fauna was present, the nitrogen addition effect on medium-quality or high-quality plant litter decomposition rate was -26% ± 5% and -29% ± 4%, respectively; these values are significantly higher than that of low-quality plant litter decomposition. The pattern is similar when soil fauna is absent. In general, the plant litter decomposition rate is decreased by soil fauna exclusion; an average inhibition of -17% ± 1.5% was exhibited across nitrogen addition treatment and litter quality groups. However, this effect is weakly related to nitrogen addition treatment and plant litter quality. We conclude that the variations in plant litter quality, nitrogen deposition, and soil fauna are important factors of decomposition and nutrient cycling in a subtropical forest ecosystem. © 2016 by the Ecological Society of America.

  19. Search Patterns

    CERN Document Server

    Morville, Peter

    2010-01-01

    What people are saying about Search Patterns "Search Patterns is a delight to read -- very thoughtful and thought provoking. It's the most comprehensive survey of designing effective search experiences I've seen." --Irene Au, Director of User Experience, Google "I love this book! Thanks to Peter and Jeffery, I now know that search (yes, boring old yucky who cares search) is one of the coolest ways around of looking at the world." --Dan Roam, author, The Back of the Napkin (Portfolio Hardcover) "Search Patterns is a playful guide to the practical concerns of search interface design. It cont

  20. Spatial and temporal variation in sources of atmospheric nitrogen deposition in the Rocky Mountains using nitrogen isotopes

    Science.gov (United States)

    Nanus, Leora; Campbell, Donald H.; Lehmann, Christopher M. B.; Mast, M. Alisa

    2018-03-01

    Variation in source areas and source types of atmospheric nitrogen (N) deposition to high-elevation ecosystems in the Rocky Mountains were evaluated using spatially and temporally distributed N isotope data from atmospheric deposition networks for 1995-2016. This unique dataset links N in wet deposition and snowpack to mobile and stationary emissions sources, and enhances understanding of the impacts of anthropogenic activities and environmental policies that mitigate effects of accelerated N cycling across the Rocky Mountain region. δ15N-NO3- at 50 U.S. Geological Survey Rocky Mountain Snowpack (Snowpack) sites ranged from -3.3‰ to +6.5‰, with a mean value of +1.4‰. At 15 National Atmospheric Deposition Program (NADP)/National Trends Network wet deposition (NADP Wetfall) sites, summer δ15N-NO3- is significantly lower ranging from -7.6‰ to -1.3‰ while winter δ15N-NO3- ranges from -2.6‰ to +5.5‰, with a mean value of +0.7‰ during the cool season. The strong seasonal difference in NADP Wetfall δ15N-NO3- is due in part to variation in the proportion of N originating from source regions at different times of the year due to seasonal changes in weather patterns. Snowpack NO3- and δ15N-NO3- are significantly related to NADP Wetfall (fall and winter) suggesting that bulk snowpack samples provide a reliable estimate at high elevations. Spatial trends show higher NO3- concentrations and δ15N-NO3- in the Southern Rocky Mountains located near larger anthropogenic N emission sources compared to the Northern Rocky Mountains. NADP Wetfall δ15N-NH4+ ranged from -10‰ to 0‰, with no observed spatial pattern. However, the lowest δ15N-NH4+(-9‰), and the highest NH4+ concentration (35 μeq/L) were observed at a Utah site dominated by local agricultural activities, whereas the higher δ15N-NH4+ observed in Colorado and Wyoming are likely due to mixed sources, including fossil fuel combustion and agricultural sources. These findings show spatial and

  1. Spatial and temporal variation in sources of atmospheric nitrogen deposition in the Rocky Mountains using nitrogen isotopes

    Science.gov (United States)

    Nanus, Leora; Campbell, Donald H.; Lehmann, Christopher M.B.; Mast, M. Alisa

    2018-01-01

    Variation in source areas and source types of atmospheric nitrogen (N) deposition to high-elevation ecosystems in the Rocky Mountains were evaluated using spatially and temporally distributed N isotope data from atmospheric deposition networks for 1995-2016. This unique dataset links N in wet deposition and snowpack to mobile and stationary emissions sources, and enhances understanding of the impacts of anthropogenic activities and environmental policies that mitigate effects of accelerated N cycling across the Rocky Mountain region. δ15N−NO3− at 50 U.S. Geological Survey Rocky Mountain Snowpack (Snowpack) sites ranged from −3.3‰ to +6.5‰, with a mean value of +1.4‰. At 15 National Atmospheric Deposition Program (NADP)/National Trends Network wet deposition (NADP Wetfall) sites, summer δ15N−NO3− is significantly lower ranging from −7.6‰ to −1.3‰ while winter δ15N−NO3− ranges from −2.6‰ to +5.5‰, with a mean value of +0.7‰ during the cool season. The strong seasonal difference in NADP Wetfall δ15N−NO3− is due in part to variation in the proportion of N originating from source regions at different times of the year due to seasonal changes in weather patterns. Snowpack NO3− and δ15N−NO3− are significantly related to NADP Wetfall (fall and winter) suggesting that bulk snowpack samples provide a reliable estimate at high elevations. Spatial trends show higher NO3−concentrations and δ15N−NO3− in the Southern Rocky Mountains located near larger anthropogenic N emission sources compared to the Northern Rocky Mountains. NADP Wetfall δ15N−NH4+ ranged from −10‰ to 0‰, with no observed spatial pattern. However, the lowest δ15N−NH4+(−9‰), and the highest NH4+ concentration (35 μeq/L) were observed at a Utah site dominated by local agricultural activities, whereas the higher δ15N−NH4+observed in Colorado and Wyoming are likely due to mixed sources, including fossil fuel combustion and

  2. A fiberoptic reflection oximeter.

    Science.gov (United States)

    Landsman, M L; Knop, N; Kwant, G; Mook, G A; Zijlstra, W G

    1978-03-20

    A catheter tip oximeter is described consisting of a cardiac catheter containing optical fibers, and incandescent light source, a light detection unit and a processing unit. Half of the optical fibers guide the light to the blood at the tip of the catheter, the other half the backscattered (reflected) light to the detection unit. The detection unit contains a dichroic mirror, transmitting most of the light with lambda less than 800 nm and reflecting most of the light with lambda greater than 900 nm, thus splitting the light into two beams. These pass through interference filters with nominal wavelengths of 640 and 920 nm respectively, and are focused on silicium barrier layer photocells. The photocell signals are amplified and fed into a divider giving the ratio of measuring (R640) and compensating (R920) photocell output. The relationship between log R640/R920 and oxygen saturation is represented by a slightly curved line. The relation may be linearized by subtracting a constant voltage from the divided output before taking the logarithm. The slope of the calibration line is dependent on the total haemoglobin concentration. Nonetheless an average calibration line can be used between 70 and 100% oxygen saturation. For 78 measurements of pig blood samples in this range (haemoglobin concentration between 96 and 161 g.1(-1)), the standard deviation of the difference between the fiberoptic oximeter and a Radiometer OSM1 oxygen saturation meter was 1.9% saturation, for 152 samples over the entire saturation range the standard deviation of the difference was 3.1% saturation. The influence of the flow velocity of blood on the light reflection depends on wavelength as well as on oxygen saturation. Therefore, complete compensation for the flow effect is not possible by simple means.

  3. Reflections on preventive medicine.

    Science.gov (United States)

    Miettinen, Olli S

    2014-10-01

    Having thought much about medicine in my career-long effort to understand it and the research for its advancement, I have come to views rather different form the now-prevailing ones in respect to what preventive medicine is about; what epidemiology is in relation to preventive medicine; what distinguishes preventive medicine in preventive healthcare at large; the relation of preventive medicine to public health; the concept of health promotion; and also the core principles of preventive medicine. All of these views I set forth in this article, for the readers' critical reflection. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Factors influencing export of dissolved inorganic nitrogen by major rivers: A new seasonal, global-scale model

    Science.gov (United States)

    Understanding sub-annual patterns of catchment dissolved inorganic nitrogen (DIN) export is critical for predicting and mitigating impacts of coastal eutrophication, such as algal blooms and hypoxic areas, which are often seasonal phenomena. We developed the first calibrated glob...

  5. Mapping Reflectance Anisotropy of a Potato Canopy Using Aerial Images Acquired with an Unmanned Aerial Vehicle

    Directory of Open Access Journals (Sweden)

    Peter P. J. Roosjen

    2017-04-01

    Full Text Available Viewing and illumination geometry has a strong influence on optical measurements of natural surfaces due to their anisotropic reflectance properties. Typically, cameras on-board unmanned aerial vehicles (UAVs are affected by this because of their relatively large field of view (FOV and thus large range of viewing angles. In this study, we investigated the magnitude of reflectance anisotropy effects in the 500–900 nm range, captured by a frame camera mounted on a UAV during a standard mapping flight. After orthorectification and georeferencing of the images collected by the camera, we calculated the viewing geometry of all observations of each georeferenced ground pixel, forming a dataset with multi-angular observations. We performed UAV flights on two days during the summer of 2016 over an experimental potato field where different zones in the field received different nitrogen fertilization treatments. These fertilization levels caused variation in potato plant growth and thereby differences in structural properties such as leaf area index (LAI and canopy cover. We fitted the Rahman–Pinty–Verstraete (RPV model through the multi-angular observations of each ground pixel to quantify, interpret, and visualize the anisotropy patterns in our study area. The Θ parameter of the RPV model, which controls the proportion of forward and backward scattering, showed strong correlation with canopy cover, where in general an increase in canopy cover resulted in a reduction of backward scattering intensity, indicating that reflectance anisotropy contains information on canopy structure. In this paper, we demonstrated that anisotropy data can be extracted from measurements using a frame camera, collected during a typical UAV mapping flight. Future research will focus on how to use the anisotropy signal as a source of information for estimation of physical vegetation properties.

  6. Matter reflects Antimatter

    CERN Document Server

    Bianconi, A.; Cristiano, A.; Leali, M.; Lodi Rizzini, E.; Venturelli, L.; Zurlo, N.

    2008-01-01

    It is common belief that the interaction between antimatter and ordinary solid matter is dominated by annihilation. However, non-destructive processes may play a relevant role too. One century ago E. Rutherford wrote about the "diffuse reflection" of alpha and beta particles by thin layers of different metals: "The observations ... of Geiger and Marsden on the scattering of alpha rays indicate that some of the alpha particles must suffer a deflexion of more than a right angle at a single encounter.... It will be shown that the main deductions from the theory are independent of whether the central charge is supposed to be positive or negative". Although the theory of electromagnetic scattering is in first approximation independent of the relative sign of the colliding particles, in the case where projectile antiprotons are shot against a wall of solid matter the Rutherford diffuse reflection mechanism competes with the annihilation process. So it is not obvious at all that a relevant part of an antiproton beam...

  7. Reflection, Interrogatory, Provocation

    International Nuclear Information System (INIS)

    Carnes, W.E.

    2016-01-01

    This invited paper advances a framing context for considering next steps in HOF and organizational culture in light of the presentations and discussions that occur during the conference. Many of the contributions during the conference will represent results of scholarly research, structured investigations, or formal organizational improvement efforts. This contribution is intended as informal reflection by a 40-year nuclear veteran on themes from other presentations considering questions such as: ''Where do we think we are?, Are we better off as an industry based on what we have done?, Where do we think we need to go?, What do we think we need to do?, and, Why do we think these things?'' Our coming together on this occasion marks 30 years since the publication of INSAG-l. As we reflect on the past, perhaps it is time to pose a series of questions. Are we sustainers of a mature technology that is in some places declining and being replaced by other energy sources? If we consider nuclear a mature technology, should we focus most on operational excellence with renewed attention to managing the unexpected? Or, is innovation still a vital part of our industry?

  8. Broadening the ecological context of ungulate-ecosystem interactions: the importance of space, seasonality, and nitrogen.

    Science.gov (United States)

    Murray, Bryan D; Webster, Christopher R; Bump, Joseph K

    2013-06-01

    Spatial heterogeneity of soil resources, particularly nitrogen availability, affects herbaceous-layer cover and diversity in temperate forest ecosystems. Current hypotheses predict that ungulate herbivores influence nitrogen availability at the stand scale, but how ungulates affect nitrogen availability at finer spatial scales that are relevant to the herb layer is less understood. We tested the hypothesis that ungulate exclusion reduces the spatial complexity of nitrogen availability at neighborhood scales (1-26 m) apart from mean stand scale effects. This outcome was expected due to a lack of ungulate nitrogenous waste deposition within exclosures and seasonally variable ungulate habitat use. To test this hypothesis we examined spatial patterning of ammonium and nitrate availability, herb-layer cover and diversity, and under-canopy solar radiation using geostatistical models. Our study sites included six stands of eastern hemlock (Tsuga canadensis) forest: three where white-tailed deer (Odocoileus virginianus) were excluded and three that were accessible to deer. Where deer were present, patch sizes of ammonium availability, cover, and diversity were smaller compared to deer exclosures, whereas mean site-level effects were not significant. Within deer exclosures cover and solar radiation were more similar in patch size than were cover and nitrogen availability. Our results suggest that browsing ungulates affect spatial patterns of herb-layer cover and diversity through the excretion of nitrogenous wastes in small, discrete patches. Ungulate-excreted nitrogen deposition and herbivory were concentrated in the dormant season, allowing herb-layer plants a greater opportunity to benefit from nitrogen additions. Therefore, the impact of ungulates on nitrogen cycling in forest ecosystems varies with spatial scale and the seasonal timing of ungulate impacts. In this way, ungulates may function as a seasonally dependent link between fine-scale and landscape

  9. Terrestrial nitrogen cycles: Some unanswered questions

    Science.gov (United States)

    Vitousek, P.

    1984-01-01

    Nitrogen is generally considered to be the element which most often limits the growth of plants in both natural and agricultural ecosystems. It regulates plant growth because photosynthetic rates are strongly dependent on the concentration of nitrogen in leaves, and because relatively large mounts of protein are required for cell division and growth. Yet nitrogen is abundant in the biosphere - the well-mixed pool in the atmosphere is considered inexhaustible compared to biotic demand, and the amount of already fixed organic nitrogen in soils far exceeds annual plant uptake in terrestrial ecosystems. In regions where natural vegetation is not nitrogen limited, continuous cultivation induces nitrogen deficiency. Nitrogen loss from cultivated lands is more rapid than that of other elements, and nitrogen fertilization is generally required to maintain crop yield under any continuous system. The pervasiveness of nitrogen deficiency in many natural and most managed sites is discussed.

  10. Transformation of fertilizer nitrogen in soil

    International Nuclear Information System (INIS)

    Soechting, H.

    1980-01-01

    Pot experiments are described in which the transformations between nitrogen added as fertilizer urea, plant-assimilated nitrogen, and different chemical fractions of soil or added straw nitrogen were studied with 15 N as a tracer. The data indicated that: (a) The transformation of added fertilizer nitrogen to immobilized amide nitrogen is decreased with added decomposable organic carbon. The transformation to immobilized α-amino N is increased, on the other hand, by the addition of decomposable organic carbon. (b) The freshly immobilized amide nitrogen is more readily remineralized than the α-amino form. The immobilization of added nitrogen continues in the presence of growing plants. (c) Mineralization of nitrogen added as 15 N-labelled straw is also increased with increasing fertilizer-nitrogen additions. (author)

  11. Aquatic subsidies transport anthropogenic nitrogen to riparian spiders

    Energy Technology Data Exchange (ETDEWEB)

    Akamatsu, Fumikazu, E-mail: f-akamt55@pwri.go.jp [Department of Environmental Sciences, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan); Toda, Hideshige [Department of Environmental Sciences, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano 390-8621 (Japan)

    2011-05-15

    Stable nitrogen isotopic composition ({delta}{sup 15}N) of aquatic biota increases with anthropogenic N inputs such as sewage and livestock waste downstream. Increase in {delta}{sup 15}N of riparian spiders downstream may reflect the anthropogenic pollution exposure through predation on aquatic insects. A two-source mixing model based on stable carbon isotopic composition showed the greatest dependence on aquatic insects (84%) by horizontal web-building spiders, followed by intermediate (48%) and low (31%) dependence by cursorial and vertical web-building spiders, respectively. The spider body size was negatively correlated with the dietary proportion of aquatic insects and spider {delta}{sup 15}N. The aquatic subsidies transported anthropogenic N to smaller riparian spiders downstream. This transport of anthropogenic N was regulated by spider's guild designation and body size. - Highlights: > {delta}{sup 15}N of aquatic insects increases downstream with anthropogenic nitrogen inputs. > {delta}{sup 15}N of riparian spiders increases with a high dietary proportion of aquatic insects and smaller spider body size. > The aquatic subsidies transport anthropogenic nitrogen to smaller riparian spiders downstream. - Smaller spiders assimilate anthropogenic nitrogen through the predation on aquatic subsides.

  12. Aquatic subsidies transport anthropogenic nitrogen to riparian spiders

    International Nuclear Information System (INIS)

    Akamatsu, Fumikazu; Toda, Hideshige

    2011-01-01

    Stable nitrogen isotopic composition (δ 15 N) of aquatic biota increases with anthropogenic N inputs such as sewage and livestock waste downstream. Increase in δ 15 N of riparian spiders downstream may reflect the anthropogenic pollution exposure through predation on aquatic insects. A two-source mixing model based on stable carbon isotopic composition showed the greatest dependence on aquatic insects (84%) by horizontal web-building spiders, followed by intermediate (48%) and low (31%) dependence by cursorial and vertical web-building spiders, respectively. The spider body size was negatively correlated with the dietary proportion of aquatic insects and spider δ 15 N. The aquatic subsidies transported anthropogenic N to smaller riparian spiders downstream. This transport of anthropogenic N was regulated by spider's guild designation and body size. - Highlights: → δ 15 N of aquatic insects increases downstream with anthropogenic nitrogen inputs. → δ 15 N of riparian spiders increases with a high dietary proportion of aquatic insects and smaller spider body size. → The aquatic subsidies transport anthropogenic nitrogen to smaller riparian spiders downstream. - Smaller spiders assimilate anthropogenic nitrogen through the predation on aquatic subsides.

  13. Replenishment and mobilization of intracellular nitrogen pools decouples wine yeast nitrogen uptake from growth

    OpenAIRE

    SANCHO FORNER, MARTA; Alicia Gutiérrez; BELTRAN CASELLAS, GEMMA; José Manuel Guillamon; Jonas Warringer

    2016-01-01

    Wine yeast capacity to take up nitrogen from the environment and catabolize it to support population growth, fermentation, and aroma production is critical to wine production. Under nitrogen restriction, yeast nitrogen uptake is believed to be intimately coupled to reproduction with nitrogen catabolite repression (NCR) suggested mediating this link. We provide a time- and strain-resolved view of nitrogen uptake, population growth, and NCR activity in wine yeasts. Nitrogen uptake was found to ...

  14. Nitrogen diffusion in zirconium nitride

    International Nuclear Information System (INIS)

    Desmaison, J.G.; Smeltzer, W.W.

    1977-01-01

    Nitrogen diffusion in polycrystalline ZrN/sub 0.71-0.79/ spheres, 60 and 90 μm diameter, was studied by the gas-solid exchange technique using 15 N as a tracer at a nitrogen pressure of 220 torr and 1000 to 1200 0 C. These specimens were characterized by chemical analyses, density, lattice parameter, and structural measurements. The tracer diffusion coefficient can be expressed as D* (cm 2 /S) = 3.0 x 10 -10 exp (-23,000/RT). This result, when compared to a previous determination obtained in the same conditions with 254 μm thick plates, confirms that nitrogen transport in this polycrystalline solid at temperatures less than 1200 0 C is associated with a short-circuit diffusion mechanism

  15. Insects as a Nitrogen Source for Plants

    Directory of Open Access Journals (Sweden)

    Michael J. Bidochka

    2013-07-01

    Full Text Available Many plants have evolved adaptations in order to survive in low nitrogen environments. One of the best-known adaptations is that of plant symbiosis with nitrogen-fixing bacteria; this is the major route by which nitrogen is incorporated into plant biomass. A portion of this plant-associated nitrogen is then lost to insects through herbivory, and insects represent a nitrogen reservoir that is generally overlooked in nitrogen cycles. In this review we show three specialized plant adaptations that allow for the recovery of insect nitrogen; that is, plants gaining nitrogen from insects. First, we show specialized adaptations by carnivorous plants in low nitrogen habitats. Insect carnivorous plants such as pitcher plants and sundews (Nepenthaceae/Sarraceniaceae and Drosera respectively are able to obtain substantial amounts of nitrogen from the insects that they capture. Secondly, numerous plants form associations with mycorrhizal fungi that can provide soluble nitrogen from the soil, some of which may be insect-derived nitrogen, obtained from decaying insects or insect frass. Finally, a specialized group of endophytic, insect-pathogenic fungi (EIPF provide host plants with insect-derived nitrogen. These soil-inhabiting fungi form a remarkable symbiosis with certain plant species. They can infect a wide range of insect hosts and also form endophytic associations in which they transfer insect-derived nitrogen to the plant. Root colonizing fungi are found in disparate fungal phylogenetic lineages, indicating possible convergent evolutionary strategies between taxa, evolution potentially driven by access to carbon-containing root exudates.

  16. Longer-term Stream Nitrogen Dynamics after Wildfire and Salvage Harvesting: Implications for Management Concepts based on Trajectories of Post-disturbance Watershed Recovery.

    Science.gov (United States)

    Silins, U.; Emelko, M. B.; Bladon, K. D.; Stone, M.; Williams, C.; Martens, A. M.; Wagner, M. J.

    2015-12-01

    Biogeochemical processes reflecting interaction of vegetation and hydrology govern long-term export of nutrients such as nitrogen, phosphorus, and carbon over successional time scales. While management concepts of watershed "recovery" from disturbance back towards pre-disturbance conditions are often considered over much shorter timescales, few studies have directly explored watershed biogeochemical responses to disturbance long enough to directly document the longer-term trajectory of responses to severe land disturbance on nitrogen export. The objectives of this study were to document both the initial magnitude and patterns of longer-term recovery of stream nitrogen after the 2003 Lost Creek wildfire over nine years in front ranges of the Rocky Mountains in south-west Alberta, Canada. The study was conducted in seven instrumented catchments (4-14 km2), including burned, burned and salvage logged, and unburned (reference) conditions since 2004. Total nitrogen (TN) and nitrate (NO3-) concentrations and area-normalized yields were greater and more variable in burned and post-fire salvage logged catchments when compared with unburned catchments. Large initial increases in stream TN and NO3- production 1-3 years after both wildfire and post-fire salvage logging declined strongly to levels similar to, or below that of unburned watersheds 4-6 years after the fire, and continued to decline (although more slowly) 7-9 years after the wildfire. Post-fire salvage logging produced lower impacts on TN and NO3- in streams and these effects declined even more rapidly compared to the effects of wildfire alone. These changes closely corresponded to the early trajectory of establishment and rapid juvenile growth of post-fire regenerating forest vegetation in both catchment groups. While the concept of hydrologic recovery from disturbance is both a practical and meaningful concept for integrated landscape management for protection of forest water resources, the benchmark for

  17. Reflection and Non-Reflection of Particle Wavepackets

    Science.gov (United States)

    Cox, Timothy; Lekner, John

    2008-01-01

    Exact closed-form solutions of the time-dependent Schrodinger equation are obtained, describing the propagation of wavepackets in the neighbourhood of a potential. Examples given include zero reflection, total reflection and partial reflection of the wavepacket, for the sech[superscript 2]x/a, 1/x[superscript 2] and delta(x) potentials,…

  18. Modeling nitrogen chemistry in combustion

    DEFF Research Database (Denmark)

    Glarborg, Peter; Miller, James A.; Ruscic, Branko

    2018-01-01

    the accuracy of engineering calculations and thereby the potential of primary measures for NOx control. In this review our current understanding of the mechanisms that are responsible for combustion-generated nitrogen-containing air pollutants is discussed. The thermochemistry of the relevant nitrogen...... via NNH or N2O are discussed, along with the chemistry of NO removal processes such as reburning and Selective Non-Catalytic Reduction of NO. Each subset of the mechanism is evaluated against experimental data and the accuracy of modeling predictions is discussed....

  19. 7. Conclusions and reflections

    OpenAIRE

    Nettle, Daniel

    2016-01-01

    But now your eyes sing the sad, sad song,Of how you lived so fast and died so young. Introduction We’ve now finished the data chapters of this book, and some conclusions are in order. In this chapter, I summarise what strike me as the main things we have learned, and suggest what their implications might be. I then devote a more extended discussion to the issue of causes of patterns of social behaviour, and how our data might bear on it. From this follows a brief consideration of what kinds o...

  20. Supplementary nitrogen in leeks based on crop nitrogen status

    NARCIS (Netherlands)

    Booij, R.; Meurs, E.J.J.

    2002-01-01

    From a number of basic relationships between several crop ecological components (Booij et al., 1996a) a system was developed for giving supplementary nitrogen application in leeks, that was based on the measurement of light interception. A description of the approach is given and a comparison is

  1. Reflecting Contemporary Design Research

    DEFF Research Database (Denmark)

    Engholm, Ida

    2017-01-01

    In recent years, design research has been the object of growing attention in universities and academies throughout the world. The present paper addresses the heterogeneous character of design research and the current need for reflection on the various approaches and interests. For this purpose......, the paper follows two steps. First, it proposes a categorization of the field in the form of a position model. The paper’s underlying assumption is that design research as a discipline exists in many different forms that cannot necessarily be brought together under one common academic research tradition......; instead it is necessary to attempt to define the field in order to initiate discussions about what constitutes the various research bases for design. Second, the paper discusses the implication for future design research when it is an interdisciplinary field that involves many disciplines, mindsets...

  2. The Reflective Methodologists

    DEFF Research Database (Denmark)

    Kjær, Bjørg

    2013-01-01

    In recent years, a focus on inclusion and vulnerable children has reignited discussions about the quality of pedagogical work. It has also initiated processes of change that have challenged the Danish kindergarten tradition and the identity of the pedagogue in a number of different ways. In this ......In recent years, a focus on inclusion and vulnerable children has reignited discussions about the quality of pedagogical work. It has also initiated processes of change that have challenged the Danish kindergarten tradition and the identity of the pedagogue in a number of different ways...... in which the practical sense and tacit knowledge are related to questions of power and social actors’ strategies for positioning themselves within a social space. This demands a particular focus on the historical effect of the concept of ‘the reflective practitioner’ as a symbolic marker of identity...

  3. Reflections on SLAP

    International Nuclear Information System (INIS)

    Cooke, Roger

    1997-01-01

    The SLAP data bases represent a major step forward in the reliability analysis of passive components. The present reflections are motivated by draft documentation for SLAP and have profited greatly from discussions with the SLAP team. We collect a number of remarks and suggestions: The use of event and failure fields to organize the data seems sensible and feasible, from a data analysis viewpoint. Influence factors, i. e. environmental influences which are affected by plant operations, are clearly important yet very difficult to accommodate in any straightforward data analysis methodology. We would welcome a serious effort to estimate the exposure in the various exposure cells. These estimates would not be based on failure records, but on knowledge of plant design and operations. Quantitative expert judgement might be a viable alternative to a massive review of all plants in the SLAP data base

  4. Reflections on Conformal Spectra

    CERN Multimedia

    CERN. Geneva

    2015-01-01

    We use modular invariance and crossing symmetry of conformal field theory to reveal approximate reflection symmetries in the spectral decompositions of the partition function in two dimensions in the limit of large central charge and of the four-point function in any dimension in the limit of large scaling dimensions Δ0 of external operators. We use these symmetries to motivate universal upper bounds on the spectrum and the operator product expansion coefficients, which we then derive by independent techniques. Some of the bounds for four-point functions are valid for finite Δ0 as well as for large Δ0. We discuss a similar symmetry in a large spacetime dimension limit. Finally, we comment on the analogue of the Cardy formula and sparse light spectrum condition for the four-point function. (based on 1510.08772 with Kim & Ooguri). This seminar will be given via videolink

  5. Reflections on academic video

    Directory of Open Access Journals (Sweden)

    Thommy Eriksson

    2012-11-01

    Full Text Available As academics we study, research and teach audiovisual media, yet rarely disseminate and mediate through it. Today, developments in production technologies have enabled academic researchers to create videos and mediate audiovisually. In academia it is taken for granted that everyone can write a text. Is it now time to assume that everyone can make a video essay? Using the online journal of academic videos Audiovisual Thinking and the videos published in it as a case study, this article seeks to reflect on the emergence and legacy of academic audiovisual dissemination. Anchoring academic video and audiovisual dissemination of knowledge in two critical traditions, documentary theory and semiotics, we will argue that academic video is in fact already present in a variety of academic disciplines, and that academic audiovisual essays are bringing trends and developments that have long been part of academic discourse to their logical conclusion.

  6. Reflections on Student Persistence

    Directory of Open Access Journals (Sweden)

    Vincent Tinto

    2017-07-01

    Full Text Available The Feature for this issue Reflections on Student Persistence has been prepared by Professor Vincent Tinto, Distinguished University Professor Emeritus at Syracuse University, United States of America (USA and a longtime friend and supporter of STARS. Vincent explores the case for motivation to be considered as a significant aspect of the tertiary student psyche by drawing on theoretical frameworks, research and practical experiences related to the issue. He synthesises this extensive, detailed, rich but often somewhat impenetrable data into a trilogy of clear and credible key dimensions of the motivation construct student self efficacy, sense of belonging and perceived value of the curriculum. This interpretation of the literature is a personal but informed reflection and is a timely piece which highlights the breadth and profundity of the presentations at this year's conference in Adelaide, Australia where students in all their diversity are central to our focus on enhancing the student experience. In this opening article, Vincent refers directly to the STARS papers selected for this Conference issue of the Journal which also address the importance of student persistence, self-efficacy and building the sense of belonging within their own institutional communities (Fernandes, Ford, Rayner & Pretorius; Kahu, Nelson, & Picton; McFarlane, Spes-Skrbis & Taib; Naylor; Smallhorn. Echoing his position on social justice and his advocacy for underserved students, Vincent reminds us that educational equity gaps still exist, and he encourages us to see the issue of persistence through the eyes of the students to support their perseverance and completion and thereby help reduce educational disadvantage.

  7. Fundamentals of thinking, patterns

    Science.gov (United States)

    Gafurov, O. M.; Gafurov, D. O.; Syryamkin, V. I.

    2018-05-01

    The authors analyze the fundamentals of thinking and propose to consider a model of the brain based on the presence of magnetic properties of gliacytes (Schwann cells) because of their oxygen saturation (oxygen has paramagnetic properties). The authors also propose to take into account the motion of electrical discharges through synapses causing electric and magnetic fields as well as additional effects such as paramagnetic resonance, which allows combining multisensory object-related information located in different parts of the brain. Therefore, the events of the surrounding world are reflected and remembered in the cortex columns, thus, creating isolated subnets with altered magnetic properties (patterns) and subsequently participate in recognition of objects, form a memory, and so on. The possibilities for the pattern-based thinking are based on the practical experience of applying methods and technologies of artificial neural networks in the form of a neuroemulator and neuromorphic computing devices.

  8. Atmospheric Nitrogen Deposition in the Western United States: Sources, Sinks and Changes over Time

    Science.gov (United States)

    Anderson, Sarah Marie

    Anthropogenic activities have greatly modified the way nitrogen moves through the atmosphere and terrestrial and aquatic environments. Excess reactive nitrogen generated through fossil fuel combustion, industrial fixation, and intensification of agriculture is not confined to anthropogenic systems but leaks into natural ecosystems with consequences including acidification, eutrophication, and biodiversity loss. A better understanding of where excess nitrogen originates and how that changes over time is crucial to identifying when, where, and to what degree environmental impacts occur. A major route into ecosystems for excess nitrogen is through atmospheric deposition. Excess nitrogen is emitted to the atmosphere where it can be transported great distances before being deposited back to the Earth's surface. Analyzing the composition of atmospheric nitrogen deposition and biological indicators that reflect deposition can provide insight into the emission sources as well as processes and atmospheric chemistry that occur during transport and what drives variation in these sources and processes. Chapter 1 provides a review and proof of concept of lichens to act as biological indicators and how their elemental and stable isotope composition can elucidate variation in amounts and emission sources of nitrogen over space and time. Information on amounts and emission sources of nitrogen deposition helps inform natural resources and land management decisions by helping to identify potentially impacted areas and causes of those impacts. Chapter 2 demonstrates that herbaria lichen specimens and field lichen samples reflect historical changes in atmospheric nitrogen deposition from urban and agricultural sources across the western United States. Nitrogen deposition increases throughout most of the 20 th century because of multiple types of emission sources until the implementation of the Clean Air Act Amendments of 1990 eventually decrease nitrogen deposition around the turn of

  9. Reflective Practices for Teacher Education

    Directory of Open Access Journals (Sweden)

    Paulus Kuswandono

    2017-01-01

    Full Text Available Studies on reflective practice in teacher education are increasingly getting more attention at least in the last 2 decades. This article discusses concepts of reflection and how it is implemented in educating pre-service teachers on their early stage of professional learning. The purposes of doing the reflection for pre-service teachers are not only for illuminating their professional learning experiences, but also to critically reflect their vocation as teachers, including the values which may be dictated to them through rigid regulations. Reflection in teacher education is crucial as it connects well with learning in that learners use reflection to exercise their mind and to evaluate their learning experiences. Besides, this article also highlights some perceived difficulties to implement reflective practice, as well as ways how to promote reflection.   DOI: https://doi.org/10.24071/llt.2012.150102

  10. Characterization of waterborne nitrogen emissions for marine eutrophication modelling in life cycle impact assessment at the damage level and global scale

    DEFF Research Database (Denmark)

    Cosme, Nuno Miguel Dias; Hauschild, Michael Zwicky

    2017-01-01

    Current life cycle impact assessment (LCIA) methods lack a consistent and globally applicable characterization model relating nitrogen (N, as dissolved inorganic nitrogen, DIN) enrichment of coastal waters to the marine eutrophication impacts at the endpoint level. This paper introduces a method...... to calculate spatially explicit characterization factors (CFs) at endpoint and damage to ecosystems levels, for waterborne nitrogen emissions, reflecting their hypoxia-related marine eutrophication impacts, modelled for 5772 river basins of the world....

  11. Guided and Unguided Student Reflections

    OpenAIRE

    Matheson, Amanda; Wood, Laura; Franklin, Scott V.

    2017-01-01

    Self-reflection is important metacognitive skill, enabling students to build coherence into their learning and embed content in a broader context. While various pedagogical techniques exist to encourage student reflection, little research has examined the differences between formally guided, partially guided and unguided reflections. This study focuses on student responses to online Guided Reflection Forms (GRFs) from students in a first-semester non-physics class and, separately, a sophomore...

  12. Students’ Learning through Reflective Journaling

    OpenAIRE

    Alvyda Liuolienė; Regina Metiūnienė

    2011-01-01

    The aim of the article is to get acquainted with the types of journals used in education to help students to learn. The paper presents some ways of fostering student’s learning through reflective journaling. It also describes the key aspects of a new method ARRIVE cycle in connection with teachers preparation to use reflective journals in a classroom. The article also presents self-assessment in reflective journaling and students’ need to self-evaluate their learning process. Reflective journ...

  13. [Temporal-spatial distribution of agricultural diffuse nitrogen pollution and relationship with soil respiration and nitrification].

    Science.gov (United States)

    Wei, Ouyang; Cai, Guan-Qing; Huang, Hao-Bo; Geng, Xiao-Jun

    2014-06-01

    The soil respiration, nitrification and denitrification processes play an important role on soil nitrogen transformation and diffuse nitrogen loading. These processes are also the chains for soil circle. In this study, the Zhegao watershed located north of Chaohu Lake was selected to explore the interactions of these processes with diffuse nitrogen pollution. The BaPS (Barometric Process Separation) was applied to analyze the soil respiration, nitrification and denitrification processes in farmland and forest. The SWAT (Soil and Water Assessment Tool) simulated the temporal and spatial pattern of diffuse nitrogen loading. As the expanding of farmland and higher level of fertilization, the yearly mean loading of diffuse nitrogen increased sustainably from 1980-1995 to 1996-2012. The monthly loading in 1996-2012 was also higher than that in the period of 1980-1995, which closely related to the precipitation. The statistical analysis indicated that there was a significant difference between two periods. The yearly averaged loading of the whole watershed in 1996-2012 was 10.40 kg x hm(-2), which was 8.10 kg x hm(-2) in 1980-1995. The variance analysis demonstrated that there was also a big difference between the spatial distributions of two periods. The forest soil had much higher soil respiration than the farmland soil. But the farmland had higher nitrification and denitrification rates. The more intensive nitrogen transformation in the farmland contributed to the less diffuse nitrogen loading. As the nitrification rate of farmland was higher than denitrification rate, agricultural diffuse nitrate nitrogen loading would increase and organic nitrogen loading would reduce. The analysis of soil respiration, nitrification and denitrification is helpful for the study of soil nitrogen circle form the aspect of soil biology, which also benefits the control of agricultural diffuse nitrogen pollution.

  14. Analysis of hyperspectral field radiometric data for monitoring nitrogen concentration in rice crops

    Science.gov (United States)

    Stroppiana, D.; Boschetti, M.; Confalonieri, R.; Bocchi, S.; Brivio, P. A.

    2005-10-01

    Monitoring crop conditions and assessing nutrition requirements is fundamental for implementing sustainable agriculture. Rational nitrogen fertilization is of particular importance in rice crops in order to guarantee high production levels while minimising the impact on the environment. In fact, the typical flooded condition of rice fields can be a significant source of greenhouse gasses. Information on plant nitrogen concentration can be used, coupled with information about the phenological stage, to plan strategies for a rational and spatially differentiated fertilization schedule. A field experiment was carried out in a rice field Northern Italy, in order to evaluate the potential of field radiometric measurements for the prediction of rice nitrogen concentration. The results indicate that rice reflectance is influenced by nitrogen supply at certain wavelengths although N concentration cannot be accurately predicted based on the reflectance measured at a given wavelength. Regression analysis highlighted that the visible region of the spectrum is most sensitive to plant nitrogen concentration when reflectance measures are combined into a spectral index. An automated procedure allowed the analysis of all the possible combinations into a Normalized Difference Index (NDI) of the narrow spectral bands derived by spectral resampling of field measurements. The derived index appeared to be least influenced by plant biomass and Leaf Area Index (LAI) providing a useful approach to detect rice nutritional status. The validation of the regressive model showed that the model is able to predict rice N concentration (R2=0.55 [p<0.01] RRMSE=29.4; modelling efficiency close to the optimum value).

  15. Reflection in Russian Educational Psychology.

    Science.gov (United States)

    Nelissen, Jo M. C.; Tomic, Welko

    This paper discusses the cultural-historical school founded by Vygotsky, Luria, and Leontiev as the theoretical background of Russian educational psychologists who have been studying how children learn to reflect. Two approaches to reflection are examined within the cultural-historical tradition: first, reflection--like other higher psychological…

  16. Reflective Practice: Origins and Interpretations

    Science.gov (United States)

    Reynolds, Michael

    2011-01-01

    The idea of reflection is central to the theory and practice of learning--especially learning which is grounded in past or current experience. This paper proposes a working definition of reflection and reviews its origins and recent developments. The author also provides an account of "critical reflection", including its rationale and…

  17. Monitoring leaf photosynthesis with canopy spectral reflectance in rice

    International Nuclear Information System (INIS)

    Tian, Y.; Zhu, Y.; Cao, W.

    2005-01-01

    We determined the quantitative relationships between leaf photosynthetic characteristics (LPC) and canopy spectral reflectance under different water supply and nitrogen application rates in rice plants. The responses of reflectance at red radiation (680 nm) to different water contents and N rates were parallel to those of leaf net photosynthetic rate (PN). The relationships of reflectance at 680 nm and ratio index of R(810,680) (near infrared/red) to PN of different leaf positions and layers indicated that the top two full leaves were the best positions for quantitative monitoring of PN with remote sensing technique, and the index R(810,680) was the best ratio index for evaluating LPC. Testing of the models with independent data sets indicated that R(810,680) could well estimate PN of the top two leaves and canopy leaf photosynthetic potential. Hence R(810,680) can be used to monitor LPC in rice under diverse growing conditions

  18. Foliage nitrogen turnover: differences among nitrogen absorbed at different times by Quercus serrata saplings

    Science.gov (United States)

    Ueda, Miki U.; Mizumachi, Eri; Tokuchi, Naoko

    2011-01-01

    Background and Aims Nitrogen turnover within plants has been intensively studied to better understand nitrogen use strategies. However, differences among the nitrogen absorbed at different times are not completely understood and the fate of nitrogen absorbed during winter is largely uncharacterized. In the present study, nitrogen absorbed at different times of the year (growing season, winter and previous growing season) was traced, and the within-leaf nitrogen turnover of a temperate deciduous oak Quercus serrata was investigated. Methods The contributions of nitrogen absorbed at the three different times to leaf construction, translocation during the growing season, and the leaf-level resorption efficiency during leaf senescence were compared using 15N. Key Results Winter- and previous growing season-absorbed nitrogen significantly contributed to leaf construction, although the contribution was smaller than that of growing season-absorbed nitrogen. On the other hand, the leaf-level resorption efficiency of winter- and previous growing season-absorbed nitrogen was higher than that of growing season-absorbed nitrogen, suggesting that older nitrogen is better retained in leaves than recently absorbed nitrogen. Conclusions The results demonstrate that nitrogen turnover in leaves varies with nitrogen absorption times. These findings are important for understanding plant nitrogen use strategies and nitrogen cycles in forest ecosystems. PMID:21515608

  19. Nitrogen trailer acceptance test report

    International Nuclear Information System (INIS)

    Kostelnik, A.J.

    1996-01-01

    This Acceptance Test Report documents compliance with the requirements of specification WHC-S-0249. The equipment was tested according to WHC-SD-WM-ATP-108 Rev.0. The equipment being tested is a portable contained nitrogen supply. The test was conducted at Norco's facility

  20. Nitrogen research for perennial crops

    International Nuclear Information System (INIS)

    Bowen, G.D.; Danso, S.K.A.

    1987-01-01

    The article describes the role of trees in restoring and maintaining soil fertility. Cropping systems that include trees can provide the ecological framework within which food, fuelwood, and fibre production can be intergrated. The IAEA has been actively involved in studies on nitrogen-fixing pasture legumes and is ready to embark on similar studies of trees. 1 tab

  1. Can mushrooms fix atmospheric nitrogen?

    Indian Academy of Sciences (India)

    Unknown

    culation was maintained as a control. At maximum mycelial colonization by the ... cant increase in nitrogen concentration were observed in the inoculated cultures compared to the controls. The mycelial weight reduction could be .... ing of Belgian Administration for Development Corpora- tion (BADC) during that period were ...

  2. Nitrogen-alloyed martensitic steels

    International Nuclear Information System (INIS)

    Berns, H.

    1988-01-01

    A report is presented on initial results with pressure-nitrided martensitic steels. In heat-resistant steels, thermal stability and toughness are raised by nitrogen. In cold work steel, there is a more favourable corrosion behaviour. (orig./MM) [de

  3. Utilization of nitrogen fixing trees

    Energy Technology Data Exchange (ETDEWEB)

    Brewbaker, J.L.; Beldt, R. van den; MacDicken, K.; Budowski, G.; Kass, D.C.L.; Russo, R.O.; Escalante, G.; Herrera, R.; Aranguren, J.; Arkcoll, D.B.; Doebereinger, J. (cord.)

    1983-01-01

    Six papers from the symposium are noted. Brewbaker, J.L., Beldt, R. van den, MacDicken, K. Fuelwood uses and properties of nitrogen-fixing trees, pp 193-204, (Refs. 15). Includes a list of 35 nitrogen-fixing trees of high fuelwood value. Budowski, G.; Kass, D.C.L.; Russo, R.O. Leguminous trees for shade, pp 205-222, (Refs. 68). Escalante, G., Herrera, R., Aranguren, J.; Nitrogen fixation in shade trees (Erythrina poeppigiana) in cocoa plantations in northern Venezuela, pp 223-230, (Refs. 13). Arkcoll, D.B.; Some leguminous trees providing useful fruits in the North of Brazil, pp 235-239, (Refs. 13). This paper deals with Parkia platycephala, Pentaclethra macroloba, Swartzia sp., Cassia leiandra, Hymenaea courbaril, dipteryz odorata, Inga edulis, I. macrophylla, and I. cinnamonea. Baggio, A.J.; Possibilities of the use of Gliricidia sepium in agroforestry systems in Brazil, pp 241-243; (Refs. 15). Seiffert, N.F.; Biological nitrogen and protein production of Leucaena cultivars grown to supplement the nutrition of ruminants, pp 245-249, (Refs. 14). Leucaena leucocephala cv. Peru, L. campina grande (L. leucocephala), and L. cunningham (L. leucocephalae) were promising for use as browse by beef cattle in central Brazil.

  4. Nitrogen deposition and terrestrial biodiversity

    Science.gov (United States)

    Christopher M. Clark; Yongfei Bai; William D. Bowman; Jane M. Cowles; Mark E. Fenn; Frank S. Gilliam; Gareth K. Phoenix; Ilyas Siddique; Carly J. Stevens; Harald U. Sverdrup; Heather L. Throop

    2013-01-01

    Nitrogen deposition, along with habitat losses and climate change, has been identified as a primary threat to biodiversity worldwide (Butchart et al., 2010; MEA, 2005; Sala et al., 2000). The source of this stressor to natural systems is generally twofold: burning of fossil fuels and the use of fertilizers in modern intensive agriculture. Each of these human...

  5. The Joys of Liquid Nitrogen.

    Science.gov (United States)

    Nolan, William T.; Gish, Thaddeus J.

    1996-01-01

    Presents 6 short experiments with liquid nitrogen that 12- and 13-year-old students can safely perform under close supervision. Helps the students in learning a number of basic chemical principles while spurring their curiosity and showing them how much fun chemistry can be. (JRH)

  6. 15N in tree rings as a bio-indicator of changing nitrogen cycling in tropical forests: an evaluation at three sites using two sampling methods

    NARCIS (Netherlands)

    Sleen, van der J.P.; Vlam, M.; Groenendijk, P.; Anten, N.P.R.; Bongers, F.; Bunyavejchewin, S.; Hietz, P.; Pons, T.L.; Zuidema, P.

    2015-01-01

    Anthropogenic nitrogen deposition is currently causing a more than twofold increase of reactive nitrogen input over large areas in the tropics. Elevated N-15 abundance (delta N-15) in the growth rings of some tropical trees has been hypothesized to reflect an increased leaching of N-15-depleted

  7. [Characteristics of dry matter production and nitrogen accumulation in barley genotypes with high nitrogen utilization efficiency].

    Science.gov (United States)

    Huang, Yi; Li, Ting-Xuan; Zhang, Xi-Zhou; Ji, Lin

    2014-07-01

    A pot experiment was conducted under low (125 mg x kg-1) and normal (250 mg x kg(-1)) nitrogen treatments. The nitrogen uptake and utilization efficiency of 22 barley cultivars were investigated, and the characteristics of dry matter production and nitrogen accumulation in barley were analyzed. The results showed that nitrogen uptake and utilization efficiency were different for barley under two nitrogen levels. The maximal values of grain yield, nitrogen utilization efficiency for grain and nitrogen harvest index were 2.87, 2.91 and 2.47 times as those of the lowest under the low nitrogen treatment. Grain yield and nitrogen utilization efficiency for grain and nitrogen harvest index of barley genotype with high nitrogen utilization efficiency were significantly greater than low nitrogen utilization efficiency, and the parameters of high nitrogen utilization efficiency genotype were 82.1%, 61.5% and 50.5% higher than low nitrogen utilization efficiency genotype under the low nitrogen treatment. Dry matter mass and nitrogen utilization of high nitrogen utilization efficiency was significantly higher than those of low nitrogen utilization efficiency. A peak of dry matter mass of high nitrogen utilization efficiency occurred during jointing to heading stage, while that of nitrogen accumulation appeared before jointing. Under the low nitrogen treatment, dry matter mass of DH61 and DH121+ was 34.4% and 38.3%, and nitrogen accumulation was 54. 8% and 58.0% higher than DH80, respectively. Dry matter mass and nitrogen accumulation seriously affected yield before jointing stage, and the contribution rates were 47.9% and 54.7% respectively under the low nitrogen treatment. The effect of dry matter and nitrogen accumulation on nitrogen utilization efficiency for grain was the largest during heading to mature stages, followed by sowing to jointing stages, with the contribution rate being 29.5% and 48.7%, 29.0% and 15.8%, respectively. In conclusion, barley genotype with high

  8. Nitrogen Dynamics Variation in Overlying Water of Jinshan Lake, China

    Directory of Open Access Journals (Sweden)

    Xiaohong Zhou

    2015-01-01

    Full Text Available Jinshan Lake is a famous urban landscape lake with approximately 8.8 km2 water area, which is located on the north of Zhenjiang, of Jiangsu Province, China. Eighteen sampled sites were selected and overlying water was sampled from 2013 to 2014 to study the seasonal and spatial variation of nitrogen in overlying water of Jinshan Lake. Results showed that physicochemical characteristics of temperature, pH, and DO showed high seasonal variation, whereas they had no significant spatial differences in the 18 sampling points (P>0.05 in overlying water of Jinshan Lake. Nitrogen concentrations showed strong seasonal variation trends. The ranked order of TN was as follows: spring > summer > autumn > winter; the order of NH4+-N was as follows: spring > autumn > summer > winter, whereas NO3--N concentrations revealed an inverse seasonal pattern, with maxima occurring in winter and minimal values occurring in spring. Nitrogen concentrations had dramatic spatial changes in 18 sampling points of Jinshan Lake. Physicochemical parameter difference, domestic wastes pollution, and rainfall runoff source may have led to seasonal and spatial fluctuation variations of nitrogen in overlying water of Jinshan Lake, China.

  9. Development of soil properties and nitrogen cycling in created wetlands

    Science.gov (United States)

    Wolf, K.L.; Ahn, C.; Noe, G.B.

    2011-01-01

    Mitigation wetlands are expected to compensate for the loss of structure and function of natural wetlands within 5–10 years of creation; however, the age-based trajectory of development in wetlands is unclear. This study investigates the development of coupled structural (soil properties) and functional (nitrogen cycling) attributes of created non-tidal freshwater wetlands of varying ages and natural reference wetlands to determine if created wetlands attain the water quality ecosystem service of nitrogen (N) cycling over time. Soil condition component and its constituents, gravimetric soil moisture, total organic carbon, and total N, generally increased and bulk density decreased with age of the created wetland. Nitrogen flux rates demonstrated age-related patterns, with younger created wetlands having lower rates of ammonification, nitrification, nitrogen mineralization, and denitrification potential than older created wetlands and natural reference wetlands. Results show a clear age-related trajectory in coupled soil condition and N cycle development, which is essential for water quality improvement. These findings can be used to enhance N processing in created wetlands and inform the regulatory evaluation of mitigation wetlands by identifying structural indicators of N processing performance.

  10. Food nitrogen footprint reductions related to a balanced Japanese diet.

    Science.gov (United States)

    Oita, Azusa; Nagano, Ichiro; Matsuda, Hiroyuki

    2018-04-01

    Dietary choices largely affect human-induced reactive nitrogen accumulation in the environment and resultant environmental problems. A nitrogen footprint (NF) is an indicator of how an individual's consumption patterns impact nitrogen pollution. Here, we examined the impact of changes in the Japanese diet from 1961 to 2011 and the effect of alternative diets (the recommended protein diet, a pescetarian diet, a low-NF food diet, and a balanced Japanese diet) on the food NF. The annual per capita Japanese food NF has increased by 55% as a result of dietary changes since 1961. The 1975 Japanese diet, a balanced omnivorous diet that reportedly delays senescence, with a protein content similar to the current level, reduced the current food NF (15.2 kg N) to 12.6 kg N, which is comparable to the level in the recommended protein diet (12.3 kg N). These findings will help consumers make dietary choices to reduce their impacts on nitrogen pollution.

  11. Photosynthate partitioning and nitrogen fixation of alfalfa and birdsfoot trefoil

    International Nuclear Information System (INIS)

    Shieh, W.J.

    1985-01-01

    Nodule mass and number are usually correlated with rates of nitrogen fixation in legumes. Birdsfoot trefoil (Lotus corniculatus L.) with more than twice the nodule number and mass, however, fixes far less nitrogen than alfalfa (Medicago sativa L.) at the same age. In this research, photosynthesis and photosynthate partitioning and utilization in relation to nitrogen fixation of alfalfa and birdsfoot trefoil were examined in order to determine their relationship to nitrogen fixation potential. Photosynthate to nodules was studied using 14 CO 2 labeling techniques. Partitioning patterns were altered by shading and dark depletion treatments. Efficiency of photosynthate utilization was examined by determining turnover of 14 C photosynthate in nodule metabolites and by studying rates of cyanide-resistant and cyanide-sensitive O 2 uptake. Alfalfa nodule activity was greater than trefoil expressed on a hole pot or nodule dry weight basis. Both shading and dark treatments significantly reduced nodule activity as estimated by the acetylene reduction assay. Shoots of both species were found to be the dominant sinks for photosynthate. Percentage 14 C recovered in alfalfa roots was more than twice that of trefoil at 1,2,3,4 and 24 h after labeling. Greater relative specific radioactivity (RSA) in nodules of both species suggests that they were stronger sinks for current photosynthate than roots

  12. Recent studies of the ocean nitrogen cycle

    Science.gov (United States)

    Eppley, R. W.

    1984-01-01

    The nitrogen cycle in the ocean is dominated by the activities of organisms. External nitrogen inputs from land and from the atmosphere are small compared with rates of consumption and production by organisms and with rates of internal rearrangements of nitrogen pools within the ocean. The chief reservoirs of nitrogen are, in decreasing order of size: nitrogen in sediments, dissolved N2, nitrate, dissolved organic nitrogen (DON), particulate organic nitrogen (PON) (mostly organisms and their by-products). The biogenic fluxes of nitrogen were reviewed. The rate of PON decomposition in the surface layer must be comparable to the rate of ammonium consumption; and at the same time the nitrate consumption rate will be similar to the rates of: (1) sinking of PON out of the surface layer and its decompositon at depth, (2) the rate of nitrification at depth, and (3) the rate of nitrate return to the surface layer by upwelling.

  13. Structural behaviour of nitrogen in oxide ceramics

    International Nuclear Information System (INIS)

    Ghauri, K.M.

    1997-01-01

    The solubility of nitrogen in molten oxides has significant consideration for two quite different types of engineering materials. The implication of a knowledge of the role of nitrogen in these oxides for refining high nitrogen steels in obvious but similar nitrogen-bearing oxide melts are of critical importance in the densification of silicon nitride ceramics. Present paper discusses structural behaviour and phase equilibria qualitatively in the light of knowledge available on slag structure through infrared and x-ray diffraction. Nitrogen solubility in glasses and related sialon based ceramics may be of paramount importance to understand the role of nitrogen in these materials as these oxides are similar in composition, structure and characteristics to sintering glasses in nitrogen ceramics. It is quite logical to infer that the same oxide model can be applied in order to massively produce nitrogen alloyed steels which are actively competing to be the materials of the next century. (author)

  14. Root patterning

    NARCIS (Netherlands)

    Scheres, Ben; Laskowski, Marta

    2016-01-01

    The mechanisms that pattern lateral root primordial are essential for the elaboration of root system architecture, a trait of key importance for future crop breeding. But which are most important: periodic or local cues? In this issue of Journal of Experimental Botany (pages 1411-1420), Kircher

  15. Granular patterns

    CERN Document Server

    Aranson, Igor S

    2009-01-01

    This title presents a review of experiments and novel theoretical concepts needed to understand the mechanisms of pattern formation in granular materials. An effort is made to connect concepts and ideas developed in granular physics with new emergent fields, especially in biology, such as cytoskeleton dynamics.

  16. Teachers’ way of reflecting

    DEFF Research Database (Denmark)

    Lund, Lea

    2016-01-01

    This paper contributes to insights on teachers’ thinking and practice by building partly on the large amount of prior research in the field of continuing professional development (in line with ISATT), and partly on examples from an empirical small-scale study executed in Denmark. The purpose of t......’ reflections on practice. Based on this model, the paper provides a proposal regarding how to work with teachers’ professional development and learning processes. Educational implications and future research directions are discussed.......This paper contributes to insights on teachers’ thinking and practice by building partly on the large amount of prior research in the field of continuing professional development (in line with ISATT), and partly on examples from an empirical small-scale study executed in Denmark. The purpose...... of the Danish study was to investigate and understand teachers’ classroom experiences using Fenstermacher’s approach to develop a practical argument, as these classroom experiences are regarded as a potential source of learning for teachers. A three-level scale model from the study describes the teach-ers...

  17. Reflectance Confocal Microscopy in Lentigo Maligna.

    Science.gov (United States)

    Gamo, R; Pampín, A; Floristán, U

    2016-12-01

    Lentigo maligna is the most common type of facial melanoma. Diagnosis is complicated, however, as it shares clinical and dermoscopic characteristics with other cutaneous lesions of the face. Reflectance confocal microscopy is an imaging technique that permits the visualization of characteristic features of lentigo maligna. These include a disrupted honeycomb pattern and pagetoid cells with a tendency to show folliculotropism. These cells typically have a dendritic morphology, although they may also appear as round cells measuring over 20μm with atypical nuclei. Poorly defined dermal papillae and atypical cells may be seen at the dermal-epidermal junction and can form bridges resembling mitochondrial structures. Other characteristic findings include junctional swelling with atypical cells located around the follicles, resembling caput medusae. Reflectance confocal microscopy is a very useful tool for diagnosing lentigo maligna. Copyright © 2016 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.

  18. Improved Canopy Sensor-based Corn Nitrogen Recommendations Using Auxiliary Information

    Science.gov (United States)

    The nitrogen (N) supplying capacity of the soil available to support corn (Zea mays L.) production can be highly variable both among and within fields. Thus, the amount of N fertilizer applied should be site-specific and also climate-sensitive. In recent years, canopy reflectance sensing has been in...

  19. Sustained effects of atmospheric [CO2] and nitrogen availability on forest soil CO2 efflux

    Science.gov (United States)

    A. Christopher Oishi; Sari Palmroth; Kurt H. Johnsen; Heather R. McCarthy; Ram. Oren

    2014-01-01

    Soil CO2 efflux (Fsoil) is the largest source of carbon from forests and reflects primary productivity as well as how carbon is allocated within forest ecosystems. Through early stages of stand development, both elevated [CO2] and availability of soil nitrogen (N; sum of mineralization, deposition, and fixation) have been shown to increase gross primary productivity,...

  20. Cost of reactive nitrogen release from human activities to the environment in the United States

    Science.gov (United States)

    The leakage of reactive nitrogen (N) from human activities to the environment can cause human health and ecological problems. Often these harmful effects are not reflected in the costs of food, fuel, and fiber that derive from N use. Spatial analyses of economic costs and benef...

  1. Sensitive Ceramics_Pattern #1-#5

    DEFF Research Database (Denmark)

    2014-01-01

    pattern of which are reflecting the position and speed of the hands. In that way the user is able to interact and model a responding pattern. The second level has to do with realizing the modules in ceramics by 3d printing directly in porcelain with a RapMan printer that coils up the 3d shape in layers...

  2. Communication Patterns, Contradictions, and Family Functions.

    Science.gov (United States)

    Yerby, Janet; Buerkel-Rothfuss, Nancy L.

    Families are rule-governed systems of interdependent individuals whose interaction follows an intricate pattern of behavior. Communication patterns in a family reflect and emerge from contradictions in rules. A function may be defined as something that a system does and must do if it is not to break down. For instance identity and stability…

  3. Nitrogen Soil Testing for Corn in Virginia

    OpenAIRE

    Evanylo, Gregory K.; Alley, Marcus M., 1947-

    2009-01-01

    An adequate supply of plant-available nitrogen (N) is crucial for efficient corn production, and corn N requirements are greater than any other nutrient. This publication reviews the link between nitrogen and corn production, nitrogen behavior, soil testing, test procedures and recommendations.

  4. 21 CFR 582.1540 - Nitrogen.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Nitrogen. 582.1540 Section 582.1540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS... Nitrogen. (a) Product. Nitrogen. (b) Conditions of use. This substance is generally recognized as safe when...

  5. 21 CFR 184.1540 - Nitrogen.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Nitrogen. 184.1540 Section 184.1540 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN... Substances Affirmed as GRAS § 184.1540 Nitrogen. (a) Nitrogen (empirical formula N2, CAS Reg. No. 7727-37-9...

  6. 46 CFR 154.1755 - Nitrogen.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Nitrogen. 154.1755 Section 154.1755 Shipping COAST GUARD... Nitrogen. Except for deck tanks and their piping systems, cargo containment systems and piping systems carrying nitrogen must be specially approved by the Commandant (CG-522). [CGD 74-289, 44 FR 26009, May 3...

  7. Nitrogen determination on tomato ( Lycopersicon esculentum Mill ...

    African Journals Online (AJOL)

    In order to investigate the effectiveness of a new method based on color image analysis and the Minolta SPAD-502 chlorophyll meter for the diagnosis of nitrogen deficiencies of tomato seedlings, a field experiment was conducted. In this study, five levels of nitrogen fertilization were established so as to induce nitrogen ...

  8. Different nitrogen sources change the transcriptome of welan gum-producing strain Sphingomonas sp. ATCC 31555.

    Science.gov (United States)

    Xu, Xiaopeng; Nie, Zuoming; Zheng, Zhiyong; Zhu, Li; Zhang, Hongtao; Zhan, Xiaobei

    2017-09-01

    To reveal effects of different nitrogen sources on the expressions and functions of genes in Sphingomonas sp. ATCC 31555, it was cultivated in medium containing inorganic nitrogen (IN), organic nitrogen (ON), or inorganic-organic combined nitrogen (CN). Welan gum production and bacterial biomass were determined, and RNA sequencing (RNA-seq) was performed. Differentially expressed genes (DEGs) between the different ATCC 31555 groups were identified, and their functions were analyzed. Welan gum production and bacterial biomass were significantly higher in the ON and CN groups compared with those in the IN group. RNA-seq produced 660 unigenes, among which 488, 731, and 844 DEGs were identified between the IN vs. ON, IN vs. CN, and ON vs. CN groups, respectively. All the DEGs were related significantly to metabolic process and signal transduction. DEGs between the IN vs. CN and ON vs. CN groups were potentially associated with bacterial chemotaxis. Real-time PCR confirmed the expressions of selected DEGs. Organic nitrogen led to higher bacterial biomass and welan gum production than inorganic nitrogen, which might reflect differences in gene expression associated with metabolic process, signal transduction, and bacterial chemotaxis induced by different nitrogen sources.

  9. Identification of genotypic variation for nitrogen response in potato (Solanum tuberosum) under low nitrogen input circumstances

    NARCIS (Netherlands)

    Tiemens-Hulscher, M.; Lammerts Van Bueren, E.; Struik, P.C.

    2009-01-01

    Nitrogen is an essential nutrient for crop growth. The demand for nitrogen in the potato crop is relatively high. However, in organic farming nitrogen input is rather limited, compared with conventional farming. In this research nine potato varieties were tested at three nitrogen levels. Genotypic

  10. Nitrogen content, 15N natural abundance and biomass of the two pleurocarpous mosses Pleurozium schreberi (Brid.) Mitt. and Scleropodium purum (Hedw.) Limpr. in relation to atmospheric nitrogen deposition

    International Nuclear Information System (INIS)

    Solga, A.; Burkhardt, J.; Zechmeister, H.G.; Frahm, J.-P.

    2005-01-01

    The suitability of the two pleurocarpous mosses Pleurozium schreberi and Scleropodium purum for assessing spatial variation in nitrogen deposition was investigated. Sampling was carried out at eight sites in the western part of Germany with bulk deposition rates ranging between 6.5 and 18.5 kg N ha -1 yr -1 . In addition to the effect of deposition on the nitrogen content of the two species, its influence on 15 N natural abundance (δ 15 N values) and on productivity was examined. Annual increases of the mosses were used for all analyses. Significant relationships between bulk N deposition and nitrogen content were obtained for both species; δ 15 N-values reflected the ratio of NH 4 -N to NO 3 -N in deposition. A negative effect of nitrogen input on productivity, i.e. decreasing biomass per area with increasing N deposition due to a reduction of stem density, was particularly evident with P. schreberi. Monitoring of N deposition by means of mosses is considered an important supplement to existing monitoring programs. It makes possible an improved spatial resolution, and thus those areas that receive high loads of nitrogen are more easily discernible. - Mosses are useful as monitors of nitrogen deposition

  11. Ruminal Nitrogen Recycling and Nitrogen Efficiency in Lactating Dairy Cattle

    OpenAIRE

    Aguilar, Michelle

    2012-01-01

    Excess nitrogen (N) excretion from animal agriculture results in reduced air and water quality, and poses a risk to human health. Although the dairy industry utilizes milk urea N (MUN) to monitor protein feeding and N excretion, phenotypic diversity among cows may influence MUN and thus bias feed management. An initial study using data from 2 previously published research trials and a field trial, observed that cow had a significant effect on MUN variation. Regression models, utilized ...

  12. Nitrogen concentrations in mosses indicate the spatial distribution of atmospheric nitrogen deposition in Europe

    International Nuclear Information System (INIS)

    Harmens, H.; Norris, D.A.; Cooper, D.M.; Mills, G.; Steinnes, E.; Kubin, E.; Thoeni, L.; Aboal, J.R.; Alber, R.; Carballeira, A.; Coskun, M.; De Temmerman, L.; Frolova, M.; Gonzalez-Miqueo, L.

    2011-01-01

    In 2005/6, nearly 3000 moss samples from (semi-)natural location across 16 European countries were collected for nitrogen analysis. The lowest total nitrogen concentrations in mosses ( 2 = 0.91) linear relationship was found between the total nitrogen concentration in mosses and measured site-specific bulk nitrogen deposition rates. The total nitrogen concentrations in mosses complement deposition measurements, helping to identify areas in Europe at risk from high nitrogen deposition at a high spatial resolution. - Highlights: → Nitrogen concentrations in mosses were determined at ca. 3000 sites across Europe. → Moss concentrations were compared with EMEP modelled nitrogen deposition. → The asymptotic relationship for Europe showed saturation at ca. 15 kg N ha -1 y -1 . → Linear relationships were found with measured nitrogen deposition in some countries. → Moss concentrations complement deposition measurements at high spatial resolution. - Mosses as biomonitors of atmospheric nitrogen deposition in Europe.

  13. EPDM Rubber Modified by Nitrogen Plasma Immersion Ion Implantation.

    Science.gov (United States)

    Kondyurin, Alexey

    2018-04-24

    Ethylene-propylene diene monomer rubber (EPDM) was treated by plasma immersion ion implantation (PIII) with nitrogen ions of 20 keV energy and fluence from 10 13 to 10 16 ions/cm². The Fourier-transform infrared attenuated total reflection spectra, atomic force microscopy and optical microscopy showed significant structure changes of the surface. The analysis of an interface of PIII treated EPDM rubber with polyurethane binder showed a cohesive character of the adhesion joint fracture at the presence of solvent and interpreted as covalent bond network formation between the PIII treated rubber and the adhesive.

  14. EPDM Rubber Modified by Nitrogen Plasma Immersion Ion Implantation

    Directory of Open Access Journals (Sweden)

    Alexey Kondyurin

    2018-04-01

    Full Text Available Ethylene-propylene diene monomer rubber (EPDM was treated by plasma immersion ion implantation (PIII with nitrogen ions of 20 keV energy and fluence from 1013 to 1016 ions/cm2. The Fourier-transform infrared attenuated total reflection spectra, atomic force microscopy and optical microscopy showed significant structure changes of the surface. The analysis of an interface of PIII treated EPDM rubber with polyurethane binder showed a cohesive character of the adhesion joint fracture at the presence of solvent and interpreted as covalent bond network formation between the PIII treated rubber and the adhesive.

  15. Proof patterns

    CERN Document Server

    Joshi, Mark

    2015-01-01

    This innovative textbook introduces a new pattern-based approach to learning proof methods in the mathematical sciences. Readers will discover techniques that will enable them to learn new proofs across different areas of pure mathematics with ease. The patterns in proofs from diverse fields such as algebra, analysis, topology and number theory are explored. Specific topics examined include game theory, combinatorics, and Euclidean geometry, enabling a broad familiarity. The author, an experienced lecturer and researcher renowned for his innovative view and intuitive style, illuminates a wide range of techniques and examples from duplicating the cube to triangulating polygons to the infinitude of primes to the fundamental theorem of algebra. Intended as a companion for undergraduate students, this text is an essential addition to every aspiring mathematician’s toolkit.

  16. Invasive insect effects on nitrogen cycling and host physiology are not tightly linked.

    Science.gov (United States)

    Rubino, Lucy; Charles, Sherley; Sirulnik, Abby G; Tuininga, Amy R; Lewis, James D

    2015-02-01

    Invasive insects may dramatically alter resource cycling and productivity in forest ecosystems. Yet, although responses of individual trees should both reflect and affect ecosystem-scale responses, relationships between physiological- and ecosystem-scale responses to invasive insects have not been extensively studied. To address this issue, we examined changes in soil nitrogen (N) cycling, N uptake and allocation, and needle biochemistry and physiology in eastern hemlock (Tsuga canadensis (L) Carr) saplings, associated with infestation by the hemlock woolly adelgid (HWA) (Adelges tsugae Annand), an invasive insect causing widespread decline of eastern hemlock in the eastern USA. Compared with uninfested saplings, infested saplings had soils that exhibited faster nitrification rates, and more needle (15)N uptake, N and total protein concentrations. However, these variables did not clearly covary. Further, within infested saplings, needle N concentration did not vary with HWA density. Light-saturated net photosynthetic rates (Asat) declined by 42% as HWA density increased from 0 to 3 adelgids per needle, but did not vary with needle N concentration. Rather, Asat varied with stomatal conductance, which was highest at the lowest HWA density and accounted for 79% of the variation in Asat. Photosynthetic light response did not differ among HWA densities. Our results suggest that the effects of HWA infestation on soil N pools and fluxes, (15)N uptake, needle N and protein concentrations, and needle physiology may not be tightly coupled under at least some conditions. This pattern may reflect direct effects of the HWA on N uptake by host trees, as well as effects of other scale-dependent factors, such as tree hydrology, affected by HWA activity. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  17. Pattern classification

    CERN Document Server

    Duda, Richard O; Stork, David G

    2001-01-01

    The first edition, published in 1973, has become a classic reference in the field. Now with the second edition, readers will find information on key new topics such as neural networks and statistical pattern recognition, the theory of machine learning, and the theory of invariances. Also included are worked examples, comparisons between different methods, extensive graphics, expanded exercises and computer project topics. An Instructor's Manual presenting detailed solutions to all the problems in the book is available from the Wiley editorial department.

  18. Nitrogen enrichment regulates calcium sources in forests

    Science.gov (United States)

    Hynicka, Justin D.; Pett-Ridge, Julie C.; Perakis, Steven

    2016-01-01

    Nitrogen (N) is a key nutrient that shapes cycles of other essential elements in forests, including calcium (Ca). When N availability exceeds ecosystem demands, excess N can stimulate Ca leaching and deplete Ca from soils. Over the long term, these processes may alter the proportion of available Ca that is derived from atmospheric deposition vs. bedrock weathering, which has fundamental consequences for ecosystem properties and nutrient supply. We evaluated how landscape variation in soil N, reflecting long-term legacies of biological N fixation, influenced plant and soil Ca availability and ecosystem Ca sources across 22 temperate forests in Oregon. We also examined interactions between soil N and bedrock Ca using soil N gradients on contrasting basaltic vs. sedimentary bedrock that differed 17-fold in underlying Ca content. We found that low-N forests on Ca-rich basaltic bedrock relied strongly on Ca from weathering, but that soil N enrichment depleted readily weatherable mineral Ca and shifted forest reliance toward atmospheric Ca. Forests on Ca-poor sedimentary bedrock relied more consistently on atmospheric Ca across all levels of soil N enrichment. The broad importance of atmospheric Ca was unexpected given active regional uplift and erosion that are thought to rejuvenate weathering supply of soil minerals. Despite different Ca sources to forests on basaltic vs. sedimentary bedrock, we observed consistent declines in plant and soil Ca availability with increasing N, regardless of the Ca content of underlying bedrock. Thus, traditional measures of Ca availability in foliage and soil exchangeable pools may poorly reflect long-term Ca sources that sustain soil fertility. We conclude that long-term soil N enrichment can deplete available Ca and cause forests to rely increasingly on Ca from atmospheric deposition, which may limit ecosystem Ca supply in an increasingly N-rich world.

  19. Effects of nitrogen stress on the photosynthetic CO2 assimilation, chlorophyll fluorescence, and sugar-nitrogen ratio in corn.

    Science.gov (United States)

    Jin, Xiuliang; Yang, Guijun; Tan, Changwei; Zhao, Chunjiang

    2015-04-01

    A field experiment was conducted using three corn cultivars (Jingyu7, Nongda80, and Tangyu10) and three nitrogen (N) application rates (0, 75, and 150 kg N ha(-1)). The objectives of this study were to investigate the responses of photosynthetic CO2 assimilation (Ph), the maximum quantum yield of photosystem II (Fv/Fm), leaf dry weight (LDW), leaf nitrogen concentration (LNC), leaf sugar concentration (LSC), and the sugar-to-nitrogen concentration ratio (S/N) to N levels in three different field-grown corn cultivars on three sampling dates. The results showed that the LDW, Fv/Fm, Ph, LNC, and LSC increased with increasing N levels, and the variation patterns of Fv/Fm, Ph, and LNC were "low-high-low". In contrast, S/N decreased with increasing N levels, and its variation pattern was "high-low-high". The values of LDW, Fv/Fm, Ph, LNC, LSC, and S/N were greatest under high N conditions, followed by medium N conditions, and finally low N conditions. Significant interactions occurred between Ph, Fv/Fm, LNC, LSC, LDW, and S/N, with the exception of the interaction between LSC and S/N and between LSC and LDW. The correlation coefficients between Ph and S/N and between Fv/Fm and S/N were -0.714 and -0.798, respectively.

  20. Adaptability of the Saccharomyces cerevisiae yeasts to wine fermentation conditions relies on their strong ability to consume nitrogen

    Science.gov (United States)

    2018-01-01

    Saccharomyces cerevisiae strains are genetically diverse, largely as a result of human efforts to develop strains specifically adapted to various fermentation processes. These adaptive pressures from various ecological niches have generated behavioral differences among these strains, particularly in terms of their nitrogen consumption capacities. In this work, we characterize this phenotype by the specific quantity of nitrogen consumed under oenological fermentation conditions using a new approach. Indeed, unlike previous studies, our experiments were conducted in an environment containing excess nitrogen, eliminating the nitrogen limitation/starvation factor that is generally observed in fermentation processes. Using these conditions, we evaluated differences in the nitrogen consumption capacities for a set of five strains from diverse origins. The strains presented extremely different phenotypes and variations in their capacities to take up nitrogen from a wine fermentation environment. These variations reflect the differences in the nitrogen uptake capacities between wine and non-wine strains. Finally, the strains differed in their ability to adapt to the nitrogen composition of the environment, leading to variations in the cellular stress states, fermentation performances and the activity of the nitrogen sensing signaling pathway. PMID:29432462