WorldWideScience

Sample records for shade tolerance canopy

  1. Canopy gradients in leaf functional traits for species that differ in growth strategies and shade tolerance.

    Science.gov (United States)

    Coble, Adam P; Fogel, Marilyn L; Parker, Geoffrey G

    2017-10-01

    In temperate deciduous forests, vertical gradients in leaf mass per area (LMA) and area-based leaf nitrogen (Narea) are strongly controlled by gradients in light availability. While there is evidence that hydrostatic constraints on leaf development may diminish LMA and Narea responses to light, inherent differences among tree species may also influence leaf developmental and morphological response to light. We investigated vertical gradients in LMA, Narea and leaf carbon isotope composition (δ13C) for three temperate deciduous species (Carpinus caroliniana Walter, Fagus grandifolia Ehrh., Liriodendron tulipifera L.) that differed in growth strategy (e.g., indeterminate and determinate growth), shade tolerance and leaf area to sapwood ratio (Al:As). Leaves were sampled across a broad range of light conditions within three vertical layers of tree crowns to maximize variation in light availability at each height and to minimize collinearity between light and height. All species displayed similar responses to light with respect to Narea and δ13C, but not for LMA. Light was more important for gradients in LMA for the shade-tolerant (C. caroliniana) and -intolerant (L. tulipifera) species with indeterminate growth, and height (e.g., hydrostatic gradients) and light were equally important for the shade-tolerant (F. grandifolia) species with determinate growth. Fagus grandifolia had a higher morphological plasticity in response to light, which may offer a competitive advantage in occupying a broader range of light conditions throughout the canopy. Differences in responses to light and height for the taller tree species, L. tulipifera and F. grandifolia, may be attributed to differences in growth strategy or Al:As, which may alter morphological and functional responses to light availability. While height was important in F. grandifolia, height was no more robust in predicting LMA than light in any of the species, confirming the strong role of light availability in

  2. Removal of nutrient limitations in forest gaps enhances growth rate and resistance to cavitation in subtropical canopy tree species differing in shade tolerance.

    Science.gov (United States)

    Villagra, Mariana; Campanello, Paula I; Montti, Lia; Goldstein, Guillermo

    2013-03-01

    A 4-year fertilization experiment with nitrogen (N) and phosphorus (P) was carried out in natural gaps of a subtropical forest in northeastern Argentina. Saplings of six dominant canopy species differing in shade tolerance were grown in five control and five N + P fertilized gaps. Hydraulic architectural traits such as wood density, the leaf area to sapwood area ratio (LA : SA), vulnerability to cavitation (P50) and specific and leaf-specific hydraulic conductivity were measured, as well as the relative growth rate, specific leaf area (SLA) and percentage of leaf damage by insect herbivores. Plant growth rates and resistance to drought-induced embolisms increased when nutrient limitations were removed. On average, the P50 of control plants was -1.1 MPa, while the P50 of fertilized plants was -1.6 MPa. Wood density and LA : SA decreased with N + P additions. A trade-off between vulnerability to cavitation and efficiency of water transport was not observed. The relative growth rate was positively related to the total leaf surface area per plant and negatively related to LA : SA, while P50 was positively related to SLA across species and treatments. Plants with higher growth rates and higher total leaf area in fertilized plots were able to avoid hydraulic dysfunction by becoming less vulnerable to cavitation (more negative P50). Two high-light-requiring species exhibited relatively low growth rates due to heavy herbivore damage. Contrary to expectations, shade-tolerant plants with relatively high resistance to hydraulic dysfunction and reduced herbivory damage were able to grow faster. These results suggest that during the initial phase of sapling establishment in gaps, species that were less vulnerable to cavitation and exhibited reduced herbivory damage had faster realized growth rates than less shade-tolerant species with higher potential growth rates. Finally, functional relationships between hydraulic traits and growth rate across species and treatments

  3. Quantification of Shading Tolerability for Photovoltaic Modules

    NARCIS (Netherlands)

    Ziar, H.; Asaei, Behzad; Farhangi, Shahrokh; Isabella, O.; Korevaar, M.A.N.; Zeman, M.

    2017-01-01

    Despite several decades of research in the field of photovoltaic (PV) systems, shading tolerance has still not been properly addressed. PV modules are influenced by shading concerning many factors, such as number and configuration of cells in the module, electrical and thermal characteristics of

  4. A novel two-step method for screening shade tolerant mutant plants via dwarfism

    Directory of Open Access Journals (Sweden)

    Wei Li

    2016-10-01

    Full Text Available When subjected to shade, plants undergo rapid shoot elongation, which often makes them more prone to disease and mechanical damage. Shade-tolerant plants can be difficult to breed; however, they offer a substantial benefit over other varieties in low-light areas. Although perennial ryegrass (Lolium perenne L. is a popular species of turf grasses because of their good appearance and fast establishment, the plant normally does not perform well under shade conditions. It has been reported that, in turfgrass, induced dwarfism can enhance shade tolerance. Here we describe a two-step procedure for isolating shade tolerant mutants of perennial ryegrass by first screening for dominant dwarf mutants, and then screening dwarf plants for shade tolerance. The two-step screening process to isolate shade tolerant mutants can be done efficiently with limited space at early seedling stages, which enables quick and efficient isolation of shade tolerant mutants, and thus facilitates development of shade tolerant new cultivars of turfgrasses. Using the method, we isolated 136 dwarf mutants from 300,000 mutagenized seeds, with 65 being shade tolerant (0.022%. When screened directly for shade tolerance, we recovered only four mutants from a population of 150,000 (0.003% mutagenized seeds. One shade tolerant mutant, shadow-1, was characterized in detail. In addition to dwarfism, shadow-1 and its sexual progeny displayed high degrees of tolerance to both natural and artificial shade. We showed that endogenous gibberellin (GA content in shadow-1 was higher than wild-type controls, and shadow-1 was also partially GA insensitive. Our novel, simple and effective two-step screening method should be applicable to breeding shade tolerant cultivars of turfgrasses, ground covers, and other economically important crop plants that can be used under canopies of existing vegetation to increase productivity per unit area of land.

  5. SUNLIT AND SHADED MAIZE CANOPY WATER LOSS UNDER VARIED WATER STRESS

    Directory of Open Access Journals (Sweden)

    Antonio Odair Santos

    1999-12-01

    Full Text Available ABSTRACT The precise estimation of transpiration from plant canopies is important for the monitoring of crop water use and management of many agricultural operations related to water use planning. The aim of this study was to estimate transpiration from sunlit and shaded fractions of a maize ( Zea mays L. canopy, using the Penman-Monteith energy balance equation with modifications introduced by Fuchs et al. (1987 and Fuchs & Cohen (1989. Estimated values were validated by a heat pulse system, which was used to measure stem sap flow and by a weighing lysimeter. A relationship between incident radiation and leaf stomatal conductance for critical levels of leaf water potential was used to estimate transpiration. Results showed that computed transpiration of the shaded canopy ranged from 27 to 45% of the total transpiration when fluctuations in atmospheric demand and the level of water stress were taken in account. Hourly and daily estimates of transpiration showed agreement with lysimeter and heat pulse measurements on the well-watered plots. For the water-limited plots the precision of the estimate decreased due to difficulties in simulating the canopy stomatal conductance.

  6. Becoming less tolerant with age: sugar maple, shade, and ontogeny.

    Science.gov (United States)

    Sendall, Kerrie M; Lusk, Christopher H; Reich, Peter B

    2015-12-01

    Although shade tolerance is often assumed to be a fixed trait, recent work suggests ontogenetic changes in the light requirements of tree species. We determined the influence of gas exchange, biomass distribution, and self-shading on ontogenetic variation in the instantaneous aboveground carbon balance of Acer saccharum. We quantified the aboveground biomass distributions of 18 juveniles varying in height and growing in low light in a temperate forest understory in Minnesota, USA. Gas exchange rates of leaf and stem tissues were measured, and the crown architecture of each individual was quantified. The YPLANT program was used to estimate the self-shaded fraction of each crown and to model net leaf-level carbon gain. Leaf respiration and photosynthesis per gram of leaf tissue increased with plant size. In contrast, stem respiration rates per gram of stem tissue declined, reflecting a shift in the distribution of stem diameter sizes from smaller (with higher respiration) to larger diameter classes. However, these trends were outweighed by ontogenetic increases in self-shading (which reduces the net photosynthesis realized) and stem mass fraction (which increases the proportion of purely respiratory tissue) in terms of influence on net carbon exchange. As a result, net carbon gain per gram of aboveground plant tissue declined with increasing plant size, and the instantaneous aboveground light compensation point increased. When estimates of root respiration were included to model whole-plant carbon gain and light compensation points, relationships with plant size were even more pronounced. Our findings show how an interplay of gas exchange, self-shading, and biomass distribution shapes ontogenetic changes in shade tolerance.

  7. Leaf traits show different relationships with shade tolerance in moist versus dry tropical forests

    NARCIS (Netherlands)

    Poorter, L.

    2009-01-01

    ¿ Shade tolerance is the central paradigm for understanding forest succession and dynamics, but there is considerable debate as to what the salient features of shade tolerance are, whether adult leaves show similar shade adaptations to seedling leaves, and whether the same leaf adaptations are found

  8. A novel two-step method for screening shade tolerant mutant plants via dwarfism

    Science.gov (United States)

    When subjected to shade, plants undergo rapid shoot elongation, which often makes them more prone to disease and mechanical damage. It has been reported that, in turfgrass, induced dwarfism can enhance shade tolerance. Here, we describe a two-step procedure for isolating shade tolerant mutants of ...

  9. An appraisal of the classic forest succession paradigm with the shade tolerance index.

    Science.gov (United States)

    Lienard, Jean; Florescu, Ionut; Strigul, Nikolay

    2015-01-01

    In this paper we revisit the classic theory of forest succession that relates shade tolerance and species replacement and assess its validity to understand patch-mosaic patterns of forested ecosystems of the USA. We introduce a macroscopic parameter called the "shade tolerance index" and compare it to the classic continuum index in southern Wisconsin forests. We exemplify shade tolerance driven succession in White Pine-Eastern Hemlock forests using computer simulations and analyzing approximated chronosequence data from the USDA FIA forest inventory. We describe this parameter across the last 50 years in the ecoregions of mainland USA, and demonstrate that it does not correlate with the usual macroscopic characteristics of stand age, biomass, basal area, and biodiversity measures. We characterize the dynamics of shade tolerance index using transition matrices and delimit geographical areas based on the relevance of shade tolerance to explain forest succession. We conclude that shade tolerance driven succession is linked to climatic variables and can be considered as a primary driving factor of forest dynamics mostly in central-north and northeastern areas in the USA. Overall, the shade tolerance index constitutes a new quantitative approach that can be used to understand and predict succession of forested ecosystems and biogeographic patterns.

  10. An appraisal of the classic forest succession paradigm with the shade tolerance index.

    Directory of Open Access Journals (Sweden)

    Jean Lienard

    Full Text Available In this paper we revisit the classic theory of forest succession that relates shade tolerance and species replacement and assess its validity to understand patch-mosaic patterns of forested ecosystems of the USA. We introduce a macroscopic parameter called the "shade tolerance index" and compare it to the classic continuum index in southern Wisconsin forests. We exemplify shade tolerance driven succession in White Pine-Eastern Hemlock forests using computer simulations and analyzing approximated chronosequence data from the USDA FIA forest inventory. We describe this parameter across the last 50 years in the ecoregions of mainland USA, and demonstrate that it does not correlate with the usual macroscopic characteristics of stand age, biomass, basal area, and biodiversity measures. We characterize the dynamics of shade tolerance index using transition matrices and delimit geographical areas based on the relevance of shade tolerance to explain forest succession. We conclude that shade tolerance driven succession is linked to climatic variables and can be considered as a primary driving factor of forest dynamics mostly in central-north and northeastern areas in the USA. Overall, the shade tolerance index constitutes a new quantitative approach that can be used to understand and predict succession of forested ecosystems and biogeographic patterns.

  11. Leaf traits show different relationships with shade tolerance in moist versus dry tropical forests.

    Science.gov (United States)

    Poorter, Lourens

    2009-03-01

    Shade tolerance is the central paradigm for understanding forest succession and dynamics, but there is considerable debate as to what the salient features of shade tolerance are, whether adult leaves show similar shade adaptations to seedling leaves, and whether the same leaf adaptations are found in forests under different climatic control. Here, adult leaf and metamer traits were measured for 39 tree species from a tropical moist semi-evergreen forest (1580 mm rain yr(-1)) and 41 species from a dry deciduous forest (1160 mm yr(-1)) in Bolivia. Twenty-six functional traits were measured and related to species regeneration light requirements.Adult leaf traits were clearly associated with shade tolerance. Different, rather than stronger, shade adaptations were found for moist compared with dry forest species. Shade adaptations exclusively found in the evergreen moist forest were related to tough and persistent leaves, and shade adaptations in the dry deciduous forest were related to high light interception and water use.These results suggest that, for forests differing in rainfall seasonality, there is a shift in the relative importance of functional leaf traits and performance trade-offs that control light partitioning. In the moist evergreen forest leaf traits underlying the growth-survival trade-off are important, whereas in the seasonally deciduous forest leaf traits underlying the growth trade-off between low and high light might become important.

  12. Plasticity in seedling morphology, biomass allocation and physiology among ten temperate tree species in response to shade is related to shade tolerance and not leaf habit.

    Science.gov (United States)

    Chmura, D J; Modrzyński, J; Chmielarz, P; Tjoelker, M G

    2017-03-01

    Mechanisms of shade tolerance in tree seedlings, and thus growth in shade, may differ by leaf habit and vary with ontogeny following seed germination. To examine early responses of seedlings to shade in relation to morphological, physiological and biomass allocation traits, we compared seedlings of 10 temperate species, varying in their leaf habit (broadleaved versus needle-leaved) and observed tolerance to shade, when growing in two contrasting light treatments - open (about 20% of full sunlight) and shade (about 5% of full sunlight). We analyzed biomass allocation and its response to shade using allometric relationships. We also measured leaf gas exchange rates and leaf N in the two light treatments. Compared to the open treatment, shading significantly increased traits typically associated with high relative growth rate (RGR) - leaf area ratio (LAR), specific leaf area (SLA), and allocation of biomass into leaves, and reduced seedling mass and allocation to roots, and net assimilation rate (NAR). Interestingly, RGR was not affected by light treatment, likely because of morphological and physiological adjustments in shaded plants that offset reductions of in situ net assimilation of carbon in shade. Leaf area-based rates of light-saturated leaf gas exchange differed among species groups, but not between light treatments, as leaf N concentration increased in concert with increased SLA in shade. We found little evidence to support the hypothesis of a increased plasticity of broadleaved species compared to needle-leaved conifers in response to shade. However, an expectation of higher plasticity in shade-intolerant species than in shade-tolerant ones, and in leaf and plant morphology than in biomass allocation was supported across species of contrasting leaf habit. © 2016 German Botanical Society and The Royal Botanical Society of the Netherlands.

  13. Relative lack of regeneration of shade-intolerant canopy species in some South African forests

    CSIR Research Space (South Africa)

    Midgley, JJ

    1995-01-01

    Full Text Available Some species such as Celtis Africana, are experiencing relative recruitment bottlenecks, because there are usually fewer recruits [i.e. individuals <20 cm diameter at breast height, (dbh)] than canopy individuals. The species with low recruitment...

  14. Acclimation of photosynthesis to lightflecks in tomato leaves: interaction with progressive shading in a growing canopy

    NARCIS (Netherlands)

    Kaiser, M.E.; Matsubara, Shizue; Harbinson, J.; Heuvelink, E.; Marcelis, L.F.M.

    2018-01-01

    Plants in natural environments are often exposed to fluctuations in light intensity, and leaf-level acclimation to light may be affected by those fluctuations. Concurrently, leaves acclimated to a given light climate can become progressively shaded as new leaves emerge and grow above them.

  15. Trichome density and its UV-B protective potential are affected by shading and leaf position on the canopy

    International Nuclear Information System (INIS)

    Liakoura, V.; Stefanou, M.; Manetas, Y.; Cholevas, C.; Karabourniotis, G.

    1997-01-01

    In Olea europaea trichome density and UV-B absorbing compounds of leaf hairs and the lamina proper of leaves located in south-facing, north-facing and the internal of the canopy were positively correlated to the UV-B midday instant irradiance measured in September at these three different positions of the canopy. The correlation between these three parameters and the receiving photosynthetically active radiation (PAR), however, was weaker. In Quercus ilex, trichome density and its UV-B absorbing capacity were considerably higher in the exposed, south-facing leaves, compared to the deeply shaded ones; the UV-B absorbing capacity of the de-haired lamina, however, was the same. In the broad-leaved, alpine rosette of Verbascum speciosum, one could distinguish two areas on the leaves, one exposed and one shaded by the superimposed lamina. Although trichome density and the UV-B absorbing compounds of the de-haired leaf were the same in the two areas, the UV-B absorbing capacity of hairs was considerably increased in the exposed region. In V. speciosum, exposure induced also qualitative changes in the UV-B absorbance profile, apparently due to the formation of new flavonoid compounds absorbing maximally at 345–350 nm. In all other cases, the differences were mainly quantitative. The results support the postulate of a function of leaf hairs as a UV-B radiation screen and suggest that trichome density and/or its UV-B absorbing capacity may depend on irradiance during leaf development

  16. Canopy gaps decrease microbial densities and disease risk for a shade-intolerant tree species

    Science.gov (United States)

    Kurt O. Reinhart; Alejandro A. Royo; Stacie A. Kageyama; Keith. Clay

    2010-01-01

    Canopy disturbances such as windthrowevents have obvious impacts on forest structure and composition aboveground, but changes in soil microbial communities and the consequences of these changes are less understood.We characterized the densities of a soil-borne pathogenic oomycete (Pythium) and a common saprotrophic zygomycete (Mortierella...

  17. The effect of gamma radiation from sources "6"0Co of soybean for shade tolerant

    International Nuclear Information System (INIS)

    Lilik Harsanti; Yulidar

    2016-01-01

    Gamma rays are electromagnetic waves that have a very strong penetrating power. One of the sources of gamma rays is from "6"0Co. The gamma rays have strong penetration power can be used of plant breeding to create new genetic diversity in the make of high-yielding varieties. Irradiation of gamma rays at a dose of 300 gray and 400 gray on soybean Denna 1 seed varieties has been done, then it was planted as M.1 the plants look healthy and robust and strong stems. The parameters observed plant height, sum book leaf, sum seed, sum pod and Percentage plant to live shade tolerant. The parameters observed were good: plant height doze 300 Gy (37.76 cm) and 400 gray (33.03 cm) The number of branches with doze 300 Gy (1.75) and 400 Gy (1.95), number of pod with doze 300 Gy (26.25) and 400 Gy (24.72), number of seed with doze 300 Gy (35.55 kg) and 400 Gy (33.65 kg), number of Naut with doze 300 Gy (9.28) and 400 Gy (8.53) and the percentage of plants capable of shade tolerant with doze 300 Gy (85) and 400 Gy(75). In conclusion, selection mutant lines of soybeans shade tolerant at generation M1 and next generation. (author)

  18. The effect of irradiance on the carbon balance and tissue characteristics of five herbaceous species differing in shade-tolerance.

    Science.gov (United States)

    Pons, Thijs L; Poorter, Hendrik

    2014-01-01

    The carbon balance is defined here as the partitioning of daily whole-plant gross CO2 assimilation (A) in C available for growth and C required for respiration (R). A scales positively with growth irradiance and there is evidence for an irradiance dependence of R as well. Here we ask if R as a fraction of A is also irradiance dependent, whether there are systematic differences in C-balance between shade-tolerant and shade-intolerant species, and what the causes could be. Growth, gas exchange, chemical composition and leaf structure were analyzed for two shade-tolerant and three shade-intolerant herbaceous species that were hydroponically grown in a growth room at five irradiances from 20 μmol m(-2) s(-1) (1.2 mol m(-2) day(-1)) to 500 μmol m(-2) s(-1) (30 mol m(-2) day(-1)). Growth analysis showed little difference between species in unit leaf rate (dry mass increase per unit leaf area) at low irradiance, but lower rates for the shade-tolerant species at high irradiance, mainly as a result of their lower light-saturated rate of photosynthesis. This resulted in lower relative growth rates in these conditions. Daily whole-plant R scaled with A in a very tight manner, giving a remarkably constant R/A ratio of around 0.3 for all but the lowest irradiance. Although some shade-intolerant species showed tendencies toward a higher R/A and inefficiencies in terms of carbon and nitrogen investment in their leaves, no conclusive evidence was found for systematic differences in C-balance between the shade-tolerant and intolerant species at the lowest irradiance. Leaf tissue of the shade-tolerant species was characterized by high dry matter percentages, C-concentration and construction costs, which could be associated with a better defense in shade environments where leaf longevity matters. We conclude that shade-intolerant species have a competitive advantage at high irradiance due to superior potential growth rates, but that shade-tolerance is not necessarily associated

  19. Seedling growth and biomass allocation in relation to leaf habit and shade tolerance among 10 temperate tree species.

    Science.gov (United States)

    Modrzyński, Jerzy; Chmura, Daniel J; Tjoelker, Mark G

    2015-08-01

    Initial growth of germinated seeds is an important life history stage, critical for establishment and succession in forests. Important questions remain regarding the differences among species in early growth potential arising from shade tolerance. In addition, the role of leaf habit in shaping relationships underlying shade tolerance-related differences in seedling growth remains unresolved. In this study we examined variation in morphological and physiological traits among seedlings of 10 forest tree species of the European temperate zone varying in shade tolerance and leaf habit (broadleaved winter-deciduous species vs needle-leaved conifers) during a 10-week period. Seeds were germinated and grown in a controlled environment simulating an intermediate forest understory light environment to resolve species differences in initial growth and biomass allocation. In the high-resource experimental conditions during the study, seedlings increased biomass allocation to roots at the cost of leaf biomass independent of shade tolerance and leaf habit. Strong correlations between relative growth rate (RGR), net assimilation rate (NAR), leaf area ratio (LAR), specific leaf area (SLA) and leaf mass fraction (LMF) indicate that physiology and biomass allocation were equally important determinants of RGR as plant structure and leaf morphology among these species. Our findings highlight the importance of seed mass- and seed size-related root morphology (specific root length-SRL) for shade tolerance during early ontogeny. Leaf and plant morphology (SLA, LAR) were more successful in explaining variation among species due to leaf habit than shade tolerance. In both broadleaves and conifers, shade-tolerant species had lower SRL and greater allocation of biomass to stems (stem mass fraction). Light-seeded shade-intolerant species with greater SRL had greater RGR in both leaf habit groups. However, the greatest plant mass was accumulated in the group of heavy-seeded shade-tolerant

  20. The effect of irradiance on the carbon balance and tissue characteristics of five herbaceous species differing in shade-tolerance

    Directory of Open Access Journals (Sweden)

    Thijs Leendert Pons

    2014-02-01

    Full Text Available Plant photosynthesis scales positively with growth irradiance. The carbon balance, defined here as the daily whole-plant gross CO2 assimilation (A partitioned in C available for growth and C required for respiration (R, is thus irradiance dependent. Here we ask if R as a fraction of A is also irradiance dependent, whether there are systematic differences in C-balance between shade-tolerant and shade-intolerant species, and what the causes could be. Growth, gas exchange, chemical composition and leaf structure were analyzed for two shade-tolerant and three shade-intolerant herbaceous species that were hydroponically grown in a growth room at five irradiances from 20 µmol m-2 s-1 (1.2 mol m-2 day-1 to 500 µmol m-2 s-1 (30 mol m-2 day-1. Growth analysis showed little difference between species in unit leaf rate (dry mass increase per unit leaf area at low irradiance, but lower rates for the shade-tolerant species at high irradiance, mainly as a result of their lower light saturated rate of photosynthesis. This resulted in lower relative growth rates in these conditions. Daily whole-plant R scaled with A in a very tight manner, giving a remarkably constant R/A ratio of around 0.3 for all but the lowest irradiance. Although some shade-intolerant species showed tendencies towards a higher R/A and inefficiencies in terms of carbon and nitrogen investment in their leaves, no conclusive evidence was found for systematic differences in C-balance between the shade-tolerant and intolerant species at the lowest irradiance. Leaf tissue of the shade-tolerant species was characterized by high dry matter percentages, C-concentration and construction costs, which could be associated with a better defense in shade environments where leaf longevity matters. We conclude that shade-intolerant species have a competitive advantage at high irradiance due to superior potential growth rates, but that shade-tolerance is not necessarily associated with a superior C

  1. Photosynthesis, photoprotection, and growth of shade-tolerant tropical tree seedlings under full sunlight.

    Science.gov (United States)

    Krause, G Heinrich; Winter, Klaus; Matsubara, Shizue; Krause, Barbara; Jahns, Peter; Virgo, Aurelio; Aranda, Jorge; García, Milton

    2012-09-01

    High solar radiation in the tropics is known to cause transient reduction in photosystem II (PSII) efficiency and CO(2) assimilation in sun-exposed leaves, but little is known how these responses affect the actual growth performance of tropical plants. The present study addresses this question. Seedlings of five woody neotropical forest species were cultivated under full sunlight and shaded conditions. In full sunlight, strong photoinhibition of PSII at midday was documented for the late-successional tree species Ormosia macrocalyx and Tetragastris panamensis and the understory/forest gap species, Piper reticulatum. In leaves of O. macrocalyx, PSII inhibition was accompanied by substantial midday depression of net CO(2) assimilation. Leaves of all species had increased pools of violaxanthin-cycle pigments. Other features of photoacclimation, such as increased Chl a/b ratio and contents of lutein, β-carotene and tocopherol varied. High light caused strong increase of tocopherol in leaves of T. panamensis and another late-successional species, Virola surinamensis. O. macrocalyx had low contents of tocopherol and UV-absorbing substances. Under full sunlight, biomass accumulation was not reduced in seedlings of T. panamensis, P. reticulatum, and V. surinamensis, but O. macrocalyx exhibited substantial growth inhibition. In the highly shade-tolerant understory species Psychotria marginata, full sunlight caused strongly reduced growth of most individuals. However, some plants showed relatively high growth rates under full sun approaching those of seedlings at 40 % ambient irradiance. It is concluded that shade-tolerant tropical tree seedlings can achieve efficient photoacclimation and high growth rates in full sunlight.

  2. Effect of smoke on subcanopy shaded light, canopy temperature, and carbon dioxide uptake in an Amazon rainforest

    OpenAIRE

    Doughty, C. E.; Flanner, M. G.; Goulden, M. L.

    2010-01-01

    Daytime Net Ecosystem CO2 uptake (NEE) in an Amazon forest has been shown to increase significantly during smoky periods associated with biomass burning. We investigated whether the increase in CO2 uptake is caused by increased irradiance in the lower canopy, which results from increased above-canopy diffuse light, or by decreased canopy temperature, which results from decreased above-canopy net radiation. We used Sun photometers measuring aerosol optical depth to find nonsmoky (Aerosol Optic...

  3. Effects of shading on morphology, physiology and grain yield of winter wheat

    DEFF Research Database (Denmark)

    Li, Huawei; Jiang, Dong; Wollenweber, Bernd

    2010-01-01

    In a field experiment, winter wheat (Triticum aestivum L.) cultivars Yangmai 158 (YM 158, shading tolerant) and Yangmai 11 (YM 11, shading-sensitive) were subjected to shading between jointing and maturity. Three shading treatments were applied, i.e. 92% (S1), 85% (S2) and 77% (S3) of full...... the shading treatments applied, leaf area index, length of the peduncle internode, area of the upper leaves and content of pigments increased, which favoured efficient light capture. Shading modified light quality in the canopy as indicated by increases of diffuse- and blue light fractions and a reduction...... the flag leaf, as in most cases Pn of the third and the penultimate leaves were found to increase under shading treatments. Shading increased the redistribution of dry matter from vegetative organs into grains. The responses of the morphological and physiological traits to shading are discussed in relation...

  4. Large-scale biotic interaction effects - tree cover interacts with shade toler-ance to affect distribution patterns of herb and shrub species across the Alps

    DEFF Research Database (Denmark)

    Nieto-Lugilde, Diego; Lenoir, Jonathan; Abdulhak, Sylvain

    2012-01-01

    on the occurrence on light-demanding species via size-asymmetric competition for light, but a facilitative effect on shade-tolerant species. In order to compare the relative importance of tree cover, four models with different combinations of variables (climate, soil and tree cover) were run for each species. Then...... role. Results indicated that high tree cover causes range contraction, especially at the upper limit, for light-demanding species, whereas it causes shade-tolerant species to extend their range upwards and downwards. Tree cover thus drives plant-plant interactions to shape plant species distribution...

  5. Convergent evolution towards high net carbon gain efficiency contributes to the shade tolerance of palms (Arecaceae)

    NARCIS (Netherlands)

    Ma, Ren Yi; Zhang, Jiao Lin; Cavaleri, Molly A.; Sterck, Frank; Strijk, J.S.; Cao, Kun Fang

    2015-01-01

    Most palm species occur in the shaded lower strata of tropical rain forests, but how their traits relate to shade adaptation is poorly understood. We hypothesized that palms are adapted to the shade of their native habitats by convergent evolution towards high net carbon gain efficiency (CGEn),

  6. Convergent Evolution towards High Net Carbon Gain Efficiency Contributes to the Shade Tolerance of Palms (Arecaceae.

    Directory of Open Access Journals (Sweden)

    Ren-Yi Ma

    Full Text Available Most palm species occur in the shaded lower strata of tropical rain forests, but how their traits relate to shade adaptation is poorly understood. We hypothesized that palms are adapted to the shade of their native habitats by convergent evolution towards high net carbon gain efficiency (CGEn, which is given by the maximum photosynthetic rate to dark respiration rate ratio. Leaf mass per area, maximum photosynthetic rate, dark respiration and N and P concentrations were measured in 80 palm species grown in a common garden, and combined with data of 30 palm species growing in their native habitats. Compared to other species from the global leaf economics data, dicotyledonous broad-leaved trees in tropical rainforest or other monocots in the global leaf economics data, palms possessed consistently higher CGEn, achieved by lowered dark respiration and fairly high foliar P concentration. Combined phylogenetic analyses of evolutionary signal and trait evolution revealed convergent evolution towards high CGEn in palms. We conclude that high CGEn is an evolutionary strategy that enables palms to better adapt to shady environments than coexisting dicot tree species, and may convey advantages in competing with them in the tropical forest understory. These findings provide important insights for understanding the evolution and ecology of palms, and for understanding plant shade adaptations of lower rainforest strata. Moreover, given the dominant role of palms in tropical forests, these findings are important for modelling carbon and nutrient cycling in tropical forest ecosystems.

  7. Size-symmetric competition in a shade-tolerant invasive plant

    DEFF Research Database (Denmark)

    Pan, Xiao-Yun; Weiner, Jacob; Li, Bo

    2013-01-01

    competition need not be size asymmetric, and suggest that tolerance to low light levels involves a reduction in phenotypic plasticity. Responses of the invasive A. philoxeroides to crowding may be an example of an invasive plant’s success in establishing dense stands of closely related individuals......, a shade‐tolerant invasive species. Stem fragments of A. philoxeroides were grown at either low or high densities (6 vs. 24 plants per pot) under three light levels (10%, 34%, and 100% full sun). After 8 weeks, survival was 31% lower in pots with a higher initial density. Both high density and low light...... levels reduced plant size substantially. Mean plant biomass ranged from 0.23 g in high‐density and low‐light pots to 4.41 g in low‐density and high‐light pots. There were no strong or significant effects of density or light level on size inequality of survivors. Most of the variation in allocation...

  8. An analytical model of stand dynamics as a function of tree growth, mortality and recruitment: the shade tolerance-stand structure hypothesis revisited.

    Science.gov (United States)

    Zavala, Miguel A; Angulo, Oscar; Bravo de la Parra, Rafael; López-Marcos, Juan C

    2007-02-07

    Light competition and interspecific differences in shade tolerance are considered key determinants of forest stand structure and dynamics. Specifically two main stand diameter distribution types as a function of shade tolerance have been proposed based on empirical observations. All-aged stands of shade tolerant species tend to have steeply descending, monotonic diameter distributions (inverse J-shaped curves). Shade intolerant species in contrast typically exhibit normal (unimodal) tree diameter distributions due to high mortality rates of smaller suppressed trees. In this study we explore the generality of this hypothesis which implies a causal relationship between light competition or shade tolerance and stand structure. For this purpose we formulate a partial differential equation system of stand dynamics as a function of individual tree growth, recruitment and mortality which allows us to explore possible individual-based mechanisms--e.g. light competition-underlying observed patterns of stand structure--e.g. unimodal or inverse J-shaped equilibrium diameter curves. We find that contrary to expectations interspecific differences in growth patterns can result alone in any of the two diameter distributions types observed in the field. In particular, slow growing species can present unimodal equilibrium curves even in the absence of light competition. Moreover, light competition and shade intolerance evaluated both at the tree growth and mortality stages did not have a significant impact on stand structure that tended to converge systematically towards an inverse J-shaped curves for most tree growth scenarios. Realistic transient stand dynamics for even aged stands of shade intolerant species (unimodal curves) were only obtained when recruitment was completely suppressed, providing further evidence on the critical role played by juvenile stages of tree development (e.g. the sampling stage) on final forest structure and composition. The results also point out the

  9. Leaf non-structural carbohydrate allocation and C:N:P stoichiometry in response to light acclimation in seedlings of two subtropical shade-tolerant tree species.

    Science.gov (United States)

    Xie, Hongtao; Yu, Mukui; Cheng, Xiangrong

    2018-03-01

    Light availability greatly affects plant growth and development. In shaded environments, plants must respond to reduced light intensity to ensure a regular rate of photosynthesis to maintain the dynamic balance of nutrients, such as leaf non-structural carbohydrates (NSCs), carbon (C), nitrogen (N) and phosphorus (P). To improve our understanding of the nutrient utilization strategies of understory shade-tolerant plants, we compared the variations in leaf NSCs, C, N and P in response to heterogeneous controlled light conditions between two subtropical evergreen broadleaf shade-tolerant species, Elaeocarpus sylvestris (E. sylvestris) and Illicium henryi (I. henryi). Light intensity treatments were applied at five levels (100%, 52%, 33%, 15% and 6% full sunlight) for 30 weeks to identify the effects of reduced light intensity on leaf NSC allocation patterns and leaf C:N:P stoichiometry characteristics. We found that leaf soluble sugar, starch and NSC concentrations in E. sylvestris showed decreasing trends with reduced light intensity, whereas I. henryi presented slightly increasing trends from 100% to 15% full sunlight and then significant decreases at extremely low light intensity (6% full sunlight). The soluble sugar/starch ratio of E. sylvestris decreased with decreasing light intensity, whereas that of I. henryi remained stable. Moreover, both species exhibited increasing trends in leaf N and P concentrations but limited leaf N:P and C:P ratio fluctuations with decreasing light intensity, revealing their adaptive strategies for poor light environments and their growth strategies under ideal light environments. There were highly significant correlations between leaf NSC variables and C:N:P stoichiometric variables in both species, revealing a trade-off in photosynthesis production between leaf NSC and carbon allocation. Thus, shade-tolerant plants readjusted their allocation of leaf NSCs, C, N and P in response to light acclimation. Redundancy analysis showed

  10. Crown traits of coniferous trees and their relation to shade tolerance can differ with leaf type: a biophysical demonstration using computed tomography scanning data

    OpenAIRE

    Dutilleul, Pierre; Han, Liwen; Valladares, Fernando; Messier, Christian

    2015-01-01

    Plant light interception and shade tolerance are intrinsically related in that they involve structural, morphological and physiological adaptations to manage light capture for photosynthetic utilization, in order to sustain survival, development and reproduction. At the scale of small-size trees, crown traits related to structural geometry of branching pattern and space occupancy through phyllotaxis can be accurately evaluated in 3D, using computed tomography (CT) scanning data. We demonstrat...

  11. Crown traits of coniferous trees and their relation to shade tolerance can differ with leaf type: A biophysical demonstration using computed tomography scanning data

    OpenAIRE

    Pierre eDutilleul; Liwen eHan; Fernando eValladeres; Christian eMessier; Christian eMessier

    2015-01-01

    Plant light interception and shade tolerance are intrinsically related in that they involve structural, morphological and physiological adaptations to manage light capture for photosynthetic utilization, in order to sustain survival, development and reproduction. At the scale of small-size trees, crown traits related to structural geometry of branching pattern and space occupancy through phyllotaxis can be accurately evaluated in 3D, using computed tomography (CT) scanning data. We demonstrat...

  12. Estimating Canopy Dark Respiration for Crop Models

    Science.gov (United States)

    Monje Mejia, Oscar Alberto

    2014-01-01

    Crop production is obtained from accurate estimates of daily carbon gain.Canopy gross photosynthesis (Pgross) can be estimated from biochemical models of photosynthesis using sun and shaded leaf portions and the amount of intercepted photosyntheticallyactive radiation (PAR).In turn, canopy daily net carbon gain can be estimated from canopy daily gross photosynthesis when canopy dark respiration (Rd) is known.

  13. Light-related variation in sapling architecture of three shade-tolerant tree species of the Mexican rain forest Variación arquitectural de árboles juveniles en relación con la luz en tres especies tolerantes a la sombra en una selva húmeda mexicana

    Directory of Open Access Journals (Sweden)

    JOSÉ LUIS MARTÍNEZ-SÁNCHEZ

    2008-09-01

    Full Text Available The crown architecture of three shade-tolerant tree species (two subcanopy and one mid-canopy was analyzed in relation to the light regime of the forest understorey. The aim was to examine to which extent shade-tolerant species variate in their crown architecture. Tree saplings (265 between 50 and 300 cm height, and distributed from understorey to variously-sized canopy gaps, were measured for 13 architectural traits in the lowland rain forest of Los Tuxtlas, México. The analysis showed that the three species changed their architecture as light increased but in a different way. No species conformed to the typical wide-crown type expected for shade-tolerant species, and in contrast they presented some traits of light demanding species. The two sub-canopy species tended to adopt a crown form between a narrow- and wide-crown type, and the mid-canopy species showed more traits of a narrow-crown type. The horizontal crown area appeared as the more related trait to the light and sapling height. It is concluded that despite being shade-tolerant, the studied species make use of better-lit environments in the forest understorey. The crown architecture of shade-tolerant species is not as rigid as originally conceived.Se analizó la arquitectura de la copa de tres especies tolerantes a la sombra (dos del sotobosque y una del dosel medio en relación con el ambiente lumínico del sotobosque de la selva. El objetivo fue examinar el grado de variación que presenta la arquitectura de la copa de especies tolerantes a la sombra. Para esto, se midieron 13 variables arquitecturales en 265 árboles juveniles (50-300 cm de altura distribuidos desde sitios de selva madura hasta claros de diversos tamaños, en la selva húmeda tropical de Los Tuxtlas, México. El análisis mostró que las tres especies cambian la arquitectura de su copa a medida que aumenta la disponibilidad de luz, pero de diferente forma. Ninguna especie presentó el típico modelo de copa plana

  14. Lack of Physiological Depth Patterns in Conspecifics of Endemic Antarctic Brown Algae: A Trade-Off between UV Stress Tolerance and Shade Adaptation?

    Directory of Open Access Journals (Sweden)

    Iván Gómez

    Full Text Available A striking characteristic of endemic Antarctic brown algae is their broad vertical distribution. This feature is largely determined by the shade adaptation in order to cope with the seasonal variation in light availability. However, during spring-summer months, when light penetrates deep in the water column these organisms have to withstand high levels of solar radiation, including UV. In the present study we examine the light use characteristics in parallel to a potential for UV tolerance (measured as content of phenolic compounds, antioxidant activity and maximum quantum yield of fluorescence in conspecific populations of four Antarctic brown algae (Ascoseira mirabilis, Desmarestia menziesii, D. anceps and Himantothallus grandifolius distributed over a depth gradient between 5 and 30 m. The main results indicated that a photosynthetic efficiency was uniform along the depth gradient in all the studied species, and b short-term (6 h exposure to UV radiation revealed a high tolerance measured as chlorophyll fluorescence, phlorotannin content and antioxidant capacity. Multivariate analysis of similarity indicated that light requirements for photosynthesis, soluble phlorotannins and antioxidant capacity are the variables determining the responses along the depth gradient in all the studied species. The suite of physiological responses of algae with a shallower distribution (A. mirabilis and D. menziesii differed from those with deeper vertical range (D. anceps and H. grandifolius. These patterns are consistent with the underwater light penetration that defines two zones: 0-15 m, with influence of UV radiation (1% of UV-B and UV-A at 9 m and 15 m respectively and a zone below 15 m marked by PAR incidence (1% up to 30 m. These results support the prediction that algae show a UV stress tolerance capacity along a broad depth range according to their marked shade adaptation. The high contents of phlorotannins and antioxidant potential appear to be

  15. Selecting Landscape Plants: Shade Trees

    OpenAIRE

    Relf, Diane; Appleton, Bonnie Lee, 1948-2012; Close, David

    2015-01-01

    Because of the permanency of trees and their importance in the landscape, care must be taken to select the best species for each situation. This publication goes over how to choose landscape trees that are shade tolerant.

  16. Crown traits of coniferous trees and their relation to shade tolerance can differ with leaf type: a biophysical demonstration using computed tomography scanning data.

    Science.gov (United States)

    Dutilleul, Pierre; Han, Liwen; Valladares, Fernando; Messier, Christian

    2015-01-01

    Plant light interception and shade tolerance are intrinsically related in that they involve structural, morphological and physiological adaptations to manage light capture for photosynthetic utilization, in order to sustain survival, development and reproduction. At the scale of small-size trees, crown traits related to structural geometry of branching pattern and space occupancy through phyllotaxis can be accurately evaluated in 3D, using computed tomography (CT) scanning data. We demonstrate this by scrutinizing the crowns of 15 potted miniature conifers of different species or varieties, classified in two groups based on leaf type (10 needlelike, 5 scalelike); we also test whether mean values of crown traits measured from CT scanning data and correlations with a shade tolerance index (STI) differ between groups. Seven crown traits, including fractal dimensions (FD1: smaller scales, FD2: larger scales) and leaf areas, were evaluated for all 15 miniature conifers; an average silhouette-to-total-area ratio was also calculated for each of the 10 needlelike-leaf conifers. Between-group differences in mean values are significant (P conifers with scalelike leaves, which had lower STI and higher FD1 on average in our study; the positive correlation between STI and ĀD is significant (P < 0.05) for the scalelike-leaf group, and very moderate for the needlelike-leaf one. A contrasting physical attachment of the leaves to branches may explain part of the between-group differences. Our findings open new avenues for the understanding of fundamental plant growth processes; the information gained could be included in a multi-scale approach to tree crown modeling.

  17. Best of both worlds: simultaneous high-light and shade-tolerance adaptations within individual leaves of the living stone Lithops aucampiae.

    Science.gov (United States)

    Field, Katie J; George, Rachel; Fearn, Brian; Quick, W Paul; Davey, Matthew P

    2013-01-01

    "Living stones" (Lithops spp.) display some of the most extreme morphological and physiological adaptations in the plant kingdom to tolerate the xeric environments in which they grow. The physiological mechanisms that optimise the photosynthetic processes of Lithops spp. while minimising transpirational water loss in both above- and below-ground tissues remain unclear. Our experiments have shown unique simultaneous high-light and shade-tolerant adaptations within individual leaves of Lithops aucampiae. Leaf windows on the upper surfaces of the plant allow sunlight to penetrate to photosynthetic tissues within while sunlight-blocking flavonoid accumulation limits incoming solar radiation and aids screening of harmful UV radiation. Increased concentration of chlorophyll a and greater chlorophyll a:b in above-ground regions of leaves enable maximum photosynthetic use of incoming light, while inverted conical epidermal cells, increased chlorophyll b, and reduced chlorophyll a:b ensure maximum absorption and use of low light levels within the below-ground region of the leaf. High NPQ capacity affords physiological flexibility under variable natural light conditions. Our findings demonstrate unprecedented physiological flexibility in a xerophyte and further our understanding of plant responses and adaptations to extreme environments.

  18. Crown traits of coniferous trees and their relation to shade tolerance can differ with leaf type: a biophysical demonstration using computed tomography scanning data

    Science.gov (United States)

    Dutilleul, Pierre; Han, Liwen; Valladares, Fernando; Messier, Christian

    2015-01-01

    Plant light interception and shade tolerance are intrinsically related in that they involve structural, morphological and physiological adaptations to manage light capture for photosynthetic utilization, in order to sustain survival, development and reproduction. At the scale of small-size trees, crown traits related to structural geometry of branching pattern and space occupancy through phyllotaxis can be accurately evaluated in 3D, using computed tomography (CT) scanning data. We demonstrate this by scrutinizing the crowns of 15 potted miniature conifers of different species or varieties, classified in two groups based on leaf type (10 needlelike, 5 scalelike); we also test whether mean values of crown traits measured from CT scanning data and correlations with a shade tolerance index (STI) differ between groups. Seven crown traits, including fractal dimensions (FD1: smaller scales, FD2: larger scales) and leaf areas, were evaluated for all 15 miniature conifers; an average silhouette-to-total-area ratio was also calculated for each of the 10 needlelike-leaf conifers. Between-group differences in mean values are significant (P < 0.05) for STI, FD1, FD2, and the average leaf area displayed (ĀD). Between-group differences in sign and strength of correlations are observed. For example, the correlation between STI and FD1 is negative and significant (P < 0.10) for the needlelike-leaf group, but is positive and significant (P < 0.05) for the miniature conifers with scalelike leaves, which had lower STI and higher FD1 on average in our study; the positive correlation between STI and ĀD is significant (P < 0.05) for the scalelike-leaf group, and very moderate for the needlelike-leaf one. A contrasting physical attachment of the leaves to branches may explain part of the between-group differences. Our findings open new avenues for the understanding of fundamental plant growth processes; the information gained could be included in a multi-scale approach to tree crown

  19. Crown traits of coniferous trees and their relation to shade tolerance can differ with leaf type: A biophysical demonstration using computed tomography scanning data

    Directory of Open Access Journals (Sweden)

    Pierre eDutilleul

    2015-03-01

    Full Text Available Plant light interception and shade tolerance are intrinsically related in that they involve structural, morphological and physiological adaptations to manage light capture for photosynthetic utilization, in order to sustain survival, development and reproduction. At the scale of small-size trees, crown traits related to structural geometry of branching pattern and space occupancy through phyllotaxis can be accurately evaluated in 3D, using computed tomography (CT scanning data. We demonstrate this by scrutinizing the crowns of 15 potted miniature conifers of different species or varieties, classified in two groups based on leaf type (10 needlelike, 5 scalelike; we also test whether mean values of crown traits measured from CT scanning data and correlations with a shade tolerance index (STI differ between groups. Seven crown traits, including fractal dimensions (FD1: smaller scales, FD2: larger scales and leaf areas, were evaluated for all 15 miniature conifers; an average silhouette-to-total-area ratio was also calculated for each of the 10 needlelike-leaf conifers. Between-group differences in mean values are significant (P < 0.05 for STI, FD1, FD2, and average leaf area displayed (A_D. Between-group differences in sign and strength of correlations are observed. For example, the correlation between STI and FD1 is negative and significant (P < 0.10 for the needlelike-leaf group, but is positive and significant (P < 0.05 for the miniature conifers with scalelike leaves, which had lower STI and higher FD1 on average in our study; the positive correlation between STI and A_D is significant (P < 0.05 for the scalelike-leaf group, and very moderate for the needlelike-leaf one. A contrasting physical attachment of leaves to branches may explain part of the between-group differences. Our findings open new avenues for the understanding of fundamental plant growth processes; the information gained could be included in a multi-scale approach to tree crown

  20. Acclimation of shade-tolerant and light-resistant Tradescantia species to growth light: chlorophyll a fluorescence, electron transport, and xanthophyll content.

    Science.gov (United States)

    Mishanin, Vladimir I; Trubitsin, Boris V; Patsaeva, Svetlana V; Ptushenko, Vasily V; Solovchenko, Alexei E; Tikhonov, Alexander N

    2017-09-01

    In this study, we have compared the photosynthetic characteristics of two contrasting species of Tradescantia plants, T. fluminensis (shade-tolerant species), and T. sillamontana (light-resistant species), grown under the low light (LL, 50-125 µmol photons m -2  s -1 ) or high light (HL, 875-1000 µmol photons m -2  s -1 ) conditions during their entire growth period. For monitoring the functional state of photosynthetic apparatus (PSA), we measured chlorophyll (Chl) a emission fluorescence spectra and kinetics of light-induced changes in the heights of fluorescence peaks at 685 and 740 nm (F 685 and F 740 ). We also compared the light-induced oxidation of P 700 and assayed the composition of carotenoids in Tradescantia leaves grown under the LL and HL conditions. The analyses of slow induction of Chl a fluorescence (SIF) uncovered different traits in the LL- and HL-grown plants of ecologically contrasting Tradescantia species, which may have potential ecophysiological significance with respect to their tolerance to HL stress. The fluorometry and EPR studies of induction events in chloroplasts in situ demonstrated that acclimation of both Tradescantia species to HL conditions promoted faster responses of their PSA as compared to LL-grown plants. Acclimation of both species to HL also caused marked changes in the leaf anatomy and carotenoid composition (an increase in Violaxanthin + Antheraxantin + Zeaxanthin and Lutein pools), suggesting enhanced photoprotective capacity of the carotenoids in the plants grown in nature under high irradiance. Collectively, the results of the present work suggest that the mechanisms of long-term PSA photoprotection in Tradescantia are based predominantly on the light-induced remodeling of pigment-protein complexes in chloroplasts.

  1. Shade tree selection and management practices by farmers in ...

    African Journals Online (AJOL)

    There is a traditional practice of forest management in coffee producing communities in Ethiopian moist Afromontane forests to increase coffee production. The practice involves removal of big canopy trees with excessive shade and selectively retaining specific tree species as preferred shade trees. This study was initiated ...

  2. Removing forest canopy cover restores a reptile assemblage.

    Science.gov (United States)

    Pike, David A; Webb, Jonathan K; Shine, Richard

    2011-01-01

    Humans are rapidly altering natural systems, leading to changes in the distribution and abundance of species. However, so many changes are occurring simultaneously (e.g., climate change, habitat fragmentation) that it is difficult to determine the cause of population fluctuations from correlational studies. We used a manipulative field experiment to determine whether forest canopy cover directly influences reptile assemblages on rock outcrops in southeastern Australia. Our experimental design consisted of three types of rock outcrops: (1) shady sites in which overgrown vegetation was manually removed (n = 25); (2) overgrown controls (n = 30); and (3) sun-exposed controls (n = 20). Following canopy removal, we monitored reptile responses over 30 months. Canopy removal increased reptile species richness, the proportion of shelter sites used by reptiles, and relative abundances of five species that prefer sun-exposed habitats. Our manipulation also decreased the abundances of two shade-tolerant species. Canopy cover thus directly influences this reptile assemblage, with the effects of canopy removal being dependent on each species' habitat preferences (i.e., selection or avoidance of sun-exposed habitat). Our study suggests that increases in canopy cover can cause declines of open-habitat specialists, as previously suggested by correlative studies from a wide range of taxa. Given that reptile colonization of manipulated outcrops occurred rapidly, artificially opening the canopy in ecologically informed ways could help to conserve imperiled species with patchy distributions and low vagility that are threatened by vegetation overgrowth. One such species is Australia's most endangered snake, the broadheaded snake (Hoplocephalus bungaroides).

  3. Shade Trees Spatial Distribution and Its Effect on Grains and Beverage Quality of Shaded Coffee Trees

    Directory of Open Access Journals (Sweden)

    Francisco José da Silva Neto

    2018-01-01

    Full Text Available Shading coffee trees has gained importance, especially among smallholders, as an option to improve the products’ quality, therefore acquiring place at the specialty coffee market, where consumers are willing to give bonus for quality. This work aims to evaluate the influence of shade trees’ spatial distribution among coffee trees’ agronomic characteristics, yield, and beans and cup quality of shaded coffee trees. The experimental design consisted of completely randomized blocks with six repetitions and four treatments: coffee trees on shade trees planting rows, distant one meter from the trunk; coffee trees on shade trees planting row, distant six meters from the trunk; and coffee plants between the rows of shade trees, parallel to the previous treatments. The parameters analyzed were plant height, canopy diameter, plagiotropic branches’ length, yield, coffee fruits’ phenological stage, ripe cherries’ Brix degree, percentage of black, unripe, and insect damaged beans, bean size, and beverage quality. Shade trees quickened coffee fruits’ phenological stage of coffee trees nearest to them. This point also showed the best beverage quality, except for overripe fruits. The remaining parameters evaluated were not affected by shade trees’ spatial distribution.

  4. Automatic Coregistration Algorithm to Remove Canopy Shaded Pixels in UAV-Borne Thermal Images to Improve the Estimation of Crop Water Stress Index of a Drip-Irrigated Cabernet Sauvignon Vineyard.

    Science.gov (United States)

    Poblete, Tomas; Ortega-Farías, Samuel; Ryu, Dongryeol

    2018-01-30

    Water stress caused by water scarcity has a negative impact on the wine industry. Several strategies have been implemented for optimizing water application in vineyards. In this regard, midday stem water potential (SWP) and thermal infrared (TIR) imaging for crop water stress index (CWSI) have been used to assess plant water stress on a vine-by-vine basis without considering the spatial variability. Unmanned Aerial Vehicle (UAV)-borne TIR images are used to assess the canopy temperature variability within vineyards that can be related to the vine water status. Nevertheless, when aerial TIR images are captured over canopy, internal shadow canopy pixels cannot be detected, leading to mixed information that negatively impacts the relationship between CWSI and SWP. This study proposes a methodology for automatic coregistration of thermal and multispectral images (ranging between 490 and 900 nm) obtained from a UAV to remove shadow canopy pixels using a modified scale invariant feature transformation (SIFT) computer vision algorithm and Kmeans++ clustering. Our results indicate that our proposed methodology improves the relationship between CWSI and SWP when shadow canopy pixels are removed from a drip-irrigated Cabernet Sauvignon vineyard. In particular, the coefficient of determination (R²) increased from 0.64 to 0.77. In addition, values of the root mean square error (RMSE) and standard error (SE) decreased from 0.2 to 0.1 MPa and 0.24 to 0.16 MPa, respectively. Finally, this study shows that the negative effect of shadow canopy pixels was higher in those vines with water stress compared with well-watered vines.

  5. Automatic Coregistration Algorithm to Remove Canopy Shaded Pixels in UAV-Borne Thermal Images to Improve the Estimation of Crop Water Stress Index of a Drip-Irrigated Cabernet Sauvignon Vineyard

    Directory of Open Access Journals (Sweden)

    Tomas Poblete

    2018-01-01

    Full Text Available Water stress caused by water scarcity has a negative impact on the wine industry. Several strategies have been implemented for optimizing water application in vineyards. In this regard, midday stem water potential (SWP and thermal infrared (TIR imaging for crop water stress index (CWSI have been used to assess plant water stress on a vine-by-vine basis without considering the spatial variability. Unmanned Aerial Vehicle (UAV-borne TIR images are used to assess the canopy temperature variability within vineyards that can be related to the vine water status. Nevertheless, when aerial TIR images are captured over canopy, internal shadow canopy pixels cannot be detected, leading to mixed information that negatively impacts the relationship between CWSI and SWP. This study proposes a methodology for automatic coregistration of thermal and multispectral images (ranging between 490 and 900 nm obtained from a UAV to remove shadow canopy pixels using a modified scale invariant feature transformation (SIFT computer vision algorithm and Kmeans++ clustering. Our results indicate that our proposed methodology improves the relationship between CWSI and SWP when shadow canopy pixels are removed from a drip-irrigated Cabernet Sauvignon vineyard. In particular, the coefficient of determination (R2 increased from 0.64 to 0.77. In addition, values of the root mean square error (RMSE and standard error (SE decreased from 0.2 to 0.1 MPa and 0.24 to 0.16 MPa, respectively. Finally, this study shows that the negative effect of shadow canopy pixels was higher in those vines with water stress compared with well-watered vines.

  6. When growing tall is not an option : contrasting shade avoidance responses in two wild Geranium species

    NARCIS (Netherlands)

    Gommers, C.M.M.

    2016-01-01

    Plants can deal with shade in different ways. Sun-adapted species express a set of growth traits to reach for light; the so-called shade avoidance syndrome (SAS). However, shade-tolerant species from the forest understory are not able to outgrow surrounding trees and adopt a tolerance strategy

  7. Sun and Shade leaves, SIF, and Photosynthetic Capacity

    Science.gov (United States)

    Berry, J. A.; Badgley, G.

    2016-12-01

    Recent advances in retrieval of solar induced chlorophyll fluorescence (SIF) have opened up new possibilities for remote sensing of canopy physiology and structure. To date most of the emphasis has been placed on SIF as an indicator of stress and photosynthetic capacity. However, it is clear that canopy structure can also have an influence. To this point, simulations of SIF in land surface models tend to under predict observed variation in SIF. Also, large, systematic differences in SIF from different canopy types seem to correlate well with the photosynthetic capacity of these canopies. SIF emissions from pampered crops can be several-fold that from evergreen, needle-leaf forests. Yet, these may have similar vegetation indices and absorb a similar fraction of incident PAR. SIF photons produced in a conifer canopy do have a lower probability of escaping its dense, clumped foliage. However, this does not explain the correlated differences in photosynthetic rate and SIF. It is useful, in this regard, to consider the separate contributions of sun and shade leaves to the SIF emitted by a canopy. Sun leaves tend to be displayed to intercept the direct solar beam, and these highly illuminated leaves are often visible from above the canopy. Sun leaves produce more SIF and a large fraction of it escapes. Therefore, the intensity of SIF may be a sensitive indicator of the partitioning of absorbed PAR to sun and shade leaves. Many models account tor the different photosynthetic capacity of sun and shade leaves in calculating canopy responses. However, the fraction of leaves in each category is usually parameterized by an assumed leaf angle distribution (e.g. spherical). In reality, the sun/shade fraction can vary over a wide range, and it has been difficult to measure. SIF and possibly near-IR reflectance of canopies can be used to specify this key parameter with obvious importance to understanding photosynthetic rate.

  8. Uniform versus asymmetric shading mediates crown recession in conifers.

    Directory of Open Access Journals (Sweden)

    Amanda L Schoonmaker

    Full Text Available In this study we explore the impact of asymmetrical vs. uniform crown shading on the mortality and growth of upper and lower branches within tree crowns, for two conifer species: shade intolerant lodgepole pine (Pinus contorta and shade tolerant white spruce (Picea glauca. We also explore xylem hydraulics, foliar nutrition, and carbohydrate status as drivers for growth and expansion of the lower and upper branches in various types of shading. This study was conducted over a two-year period across 10 regenerating forest sites dominated by lodgepole pine and white spruce, in the lower foothills of Alberta, Canada. Trees were assigned to one of four shading treatments: (1, complete uniform shading of the entire tree, (2 light asymmetric shading where the lower 1/4-1/3 of the tree crown was shaded, (3 heavy asymmetric shading as in (2 except with greater light reduction and (4 control in which no artificial shading occurred and most of the entire crown was exposed to full light. Asymmetrical shading of only the lower crown had a larger negative impact on the bud expansion and growth than did uniform shading, and the effect was stronger in pine relative to spruce. In addition, lower branches in pine also had lower carbon reserves, and reduced xylem-area specific conductivity compared to spruce. For both species, but particularly the pine, the needles of lower branches tended to store less C than upper branches in the asymmetric shade, which could suggest a movement of reserves away from the lower branches. The implications of these findings correspond with the inherent shade tolerance and self-pruning behavior of these conifers and supports a carbon based mechanism for branch mortality--mediated by an asymmetry in light exposure of the crown.

  9. Seagrass canopy photosynthetic response is a function of canopy density and light environment: a model for Amphibolis griffithii.

    Science.gov (United States)

    Hedley, John D; McMahon, Kathryn; Fearns, Peter

    2014-01-01

    A three-dimensional computer model of canopies of the seagrass Amphibolis griffithii was used to investigate the consequences of variations in canopy structure and benthic light environment on leaf-level photosynthetic saturation state. The model was constructed using empirical data of plant morphometrics from a previously conducted shading experiment and validated well to in-situ data on light attenuation in canopies of different densities. Using published values of the leaf-level saturating irradiance for photosynthesis, results show that the interaction of canopy density and canopy-scale photosynthetic response is complex and non-linear, due to the combination of self-shading and the non-linearity of photosynthesis versus irradiance (P-I) curves near saturating irradiance. Therefore studies of light limitation in seagrasses should consider variation in canopy structure and density. Based on empirical work, we propose a number of possible measures for canopy scale photosynthetic response that can be plotted to yield isoclines in the space of canopy density and light environment. These plots can be used to interpret the significance of canopy changes induced as a response to decreases in the benthic light environment: in some cases canopy thinning can lead to an equivalent leaf level light environment, in others physiological changes may also be required but these alone may be inadequate for canopy survival. By providing insight to these processes the methods developed here could be a valuable management tool for seagrass conservation during dredging or other coastal developments.

  10. Seagrass canopy photosynthetic response is a function of canopy density and light environment: a model for Amphibolis griffithii.

    Directory of Open Access Journals (Sweden)

    John D Hedley

    Full Text Available A three-dimensional computer model of canopies of the seagrass Amphibolis griffithii was used to investigate the consequences of variations in canopy structure and benthic light environment on leaf-level photosynthetic saturation state. The model was constructed using empirical data of plant morphometrics from a previously conducted shading experiment and validated well to in-situ data on light attenuation in canopies of different densities. Using published values of the leaf-level saturating irradiance for photosynthesis, results show that the interaction of canopy density and canopy-scale photosynthetic response is complex and non-linear, due to the combination of self-shading and the non-linearity of photosynthesis versus irradiance (P-I curves near saturating irradiance. Therefore studies of light limitation in seagrasses should consider variation in canopy structure and density. Based on empirical work, we propose a number of possible measures for canopy scale photosynthetic response that can be plotted to yield isoclines in the space of canopy density and light environment. These plots can be used to interpret the significance of canopy changes induced as a response to decreases in the benthic light environment: in some cases canopy thinning can lead to an equivalent leaf level light environment, in others physiological changes may also be required but these alone may be inadequate for canopy survival. By providing insight to these processes the methods developed here could be a valuable management tool for seagrass conservation during dredging or other coastal developments.

  11. Tolerance

    DEFF Research Database (Denmark)

    Tønder, Lars

    is linked to a different set of circumstances than the ones suggested by existing models in contemporary democratic theory. Reorienting the discussion of tolerance, the book raises the question of how to disclose new possibilities within our given context of affect and perception. Once we move away from......Tolerance: A Sensorial Orientation to Politics is an experiment in re-orientation. The book is based on the wager that tolerance exceeds the more prevalent images of self-restraint and repressive benevolence because neither precludes the possibility of a more “active tolerance” motivated...... by the desire to experiment and to become otherwise. The objective is to discuss what gets lost, conceptually as well as politically, when we neglect the subsistence of active tolerance within other practices of tolerance, and to develop a theory of active tolerance in which tolerance's mobilizing character...

  12. Bird communities in sun and shade coffee farms in Kenya

    Directory of Open Access Journals (Sweden)

    C. Smith

    2015-07-01

    Full Text Available Agricultural expansion to meet rising crop demand is one of the greatest threats to terrestrial biodiversity. Coffee, one of the most valuable trade items in tropical countries, can provide both economic livelihood and wildlife habitat. Previous work, conducted primarily on Neotropical coffee farms, indicates that birds are generally more abundant and diverse in farms with a canopy of shade trees, though regional variation exists. To date, few studies have examined birds on coffee farms in Africa, which contains 20% of the world’s coffee acreage. We studied differences in the bird communities between sun and shade monoculture coffee in central Kenya, and we examined effects of vegetation on bird abundance and diversity. Sun coffee had higher species richness and abundances of all major guilds (omnivores, insectivores, and granivores, and showed low community similarity to shade. Unlike findings from the Neotropics, canopy cover appeared to have a negative influence on all guilds, while understory volume of weeds increased bird abundance and species richness with a similar magnitude as canopy cover. These differences highlight the need for further studies in the general East Africa region with a wider variety of shade coffee systems.

  13. Tolerance

    DEFF Research Database (Denmark)

    Tønder, Lars

    Tolerance: A Sensorial Orientation to Politics is an experiment in re-orientation. The book is based on the wager that tolerance exceeds the more prevalent images of self-restraint and repressive benevolence because neither precludes the possibility of a more “active tolerance” motivated by the d...... these alternatives by returning to the notion of tolerance as the endurance of pain, linking this notion to exemplars and theories relevant to the politics of multiculturalism, religious freedom, and free speech....

  14. Effect of shade on photosynthetic pigments in the tropical root crops: yam, taro, tannia, cassava and sweet potato

    International Nuclear Information System (INIS)

    Johnston, M.; Onwueme, I.C.

    1998-01-01

    Plants of yam, taro, tannia, cassava and sweet potato were raised under shade or in full sunlight and the effect of shade on leaf chlorophyll and carotenoids was examined to determine and compare the relative shade tolerance and adaptability of the var ious species. All five species of root crops adapted to shade. The chlorophyll concentration was higher, while the chlorophyll a:b ratio, carotenoids per unit chlorophyll and the weight per unit area of leaf were lower in the shade than in the sun in yam, tannia, taro, cassava and sweet potato. All species had larger leaves and more chlorophyll per leaf in the shade. The extent of the changes, however, differed between species. The aroids (taro and tannia) appeared to be shade-tolerant species as their chlorophyll a:b ratios changed less than those of the other species in the shade, suggesting that their light-harvesting systems may be normally adapted to shade conditions. Taro and tannia also adapted to shade by a greater proportional increase in leaf size, a smaller reduction in leaf weight per unit area and a greater proportional increase in chlorophyll and carotenoids per leaf than the other species. Yam compensated for shade by having a large proportional increase in leaf size and appeared to be moderately tolerant of shade. Sweet potato and cassava appeared to be the least tolerant of shade of the major tropical root crops. (author)

  15. Climbing plants in a temperate rainforest understorey: searching for high light or coping with deep shade?

    Science.gov (United States)

    Valladares, Fernando; Gianoli, Ernesto; Saldaña, Alfredo

    2011-08-01

    While the climbing habit allows vines to reach well-lit canopy areas with a minimum investment in support biomass, many of them have to survive under the dim understorey light during certain stages of their life cycle. But, if the growth/survival trade-off widely reported for trees hold for climbing plants, they cannot maximize both light-interception efficiency and shade avoidance (i.e. escaping from the understorey). The seven most important woody climbers occurring in a Chilean temperate evergreen rainforest were studied with the hypothesis that light-capture efficiency of climbers would be positively associated with their abundance in the understorey. Species abundance in the understorey was quantified from their relative frequency and density in field plots, the light environment was quantified by hemispherical photography, the photosynthetic response to light was measured with portable gas-exchange analyser, and the whole shoot light-interception efficiency and carbon gain was estimated with the 3-D computer model Y-plant. Species differed in specific leaf area, leaf mass fraction, above ground leaf area ratio, light-interception efficiency and potential carbon gain. Abundance of species in the understorey was related to whole shoot features but not to leaf level features such as specific leaf area. Potential carbon gain was inversely related to light-interception efficiency. Mutual shading among leaves within a shoot was very low (<20 %). The abundance of climbing plants in this southern rainforest understorey was directly related to their capacity to intercept light efficiently but not to their potential carbon gain. The most abundant climbers in this ecosystem match well with a shade-tolerance syndrome in contrast to the pioneer-like nature of climbers observed in tropical studies. The climbers studied seem to sacrifice high-light searching for coping with the dim understorey light.

  16. Shade response of a full size TESSERA module

    Science.gov (United States)

    Slooff, Lenneke H.; Carr, Anna J.; de Groot, Koen; Jansen, Mark J.; Okel, Lars; Jonkman, Rudi; Bakker, Jan; de Gier, Bart; Harthoorn, Adriaan

    2017-08-01

    A full size TESSERA shade tolerant module has been made and was tested under various shadow conditions. The results show that the dedicated electrical interconnection of cells result in an almost linear response under shading. Furthermore, the voltage at maximum power point is almost independent of the shadow. This decreases the demand on the voltage range of the inverter. The increased shadow linearity results in a calculated increase in annual yield of about 4% for a typical Dutch house.

  17. Role of riparian shade on the fish assemblage of a reservoir littoral

    Science.gov (United States)

    Raines, C. D.; Miranda, Leandro E.

    2016-01-01

    Research into the effects of shade on reservoir fish assemblages is lacking, with most investigations focused on streams. Unlike many streams, the canopy in a reservoir shades only a narrow fringe of water adjacent to the shoreline, and may not have the influential effect on the aquatic environment reported in streams. We compared fish assemblages between shaded and unshaded sites in a shallow reservoir. Overall species richness (gamma diversity) was higher in shaded sites, and fish assemblage composition differed between shaded and unshaded sites. Average light intensity was 66 % lower in shaded sites, and differences in average temperature and dissolved oxygen were small. Unlike streams where shade can have large effects on water physicochemistry, in reservoirs shade-related differences in fish assemblages seemed to be linked principally to differences in light intensity. Diversity in light intensity in shaded and unshaded sites in reservoirs can create various mosaics of light-based habitats that enable diversity of species assemblages. Managing to promote the habitat diversity provided by shade may require coping with the artificial nature of reservoir riparian zones and water level fluctuations.

  18. Solar shading how to integrate solar shading in sustainable buildings

    CERN Document Server

    Dolmans, Dick; Dutoo, Gonzague; Hall, Anders; Seppänen, Olli

    2010-01-01

    Solar Shading Guidebook gives a solid background on the physics of solar radiation and its behaviour in window with solar shading systems. Major focus of the Guidebook is on the effect of solar shading in the use of energy for cooling, heating and lighting. The book gives also practical guidance for selection, installation and operation of solar shading as well as future trends in integration of HVAC-systems with solar control.

  19. Tints, Shades and Frost

    Science.gov (United States)

    Sterling, Joan

    2009-01-01

    This article describes a classroom art project inspired by the work of Robert Frost, one of the most acclaimed and beloved American poets of all time. Using tints and shades in a composition, this project demonstrates how quality literature may be incorporated into elementary art lessons in a very useful way, making art an important complement to…

  20. Shading effect on generative characters of upland red rice of Southeast Sulawesi, Indonesia

    Science.gov (United States)

    Muhidin; Syam’un, E.; Kaimuddin; Musa, Y.; Sadimantara, G. R.; Usman; Leomo, S.; Rakian, T. C.

    2018-05-01

    Upland red rice (Oryza sativa) contains anthocyanin, a phenolic compounds that can act as antioxidants and functional food for human dietary. The content of functional food on upland red rice is influenced by shading condition, but the production is also influenced by environmental condition, especially the availability of light. The study aims is to assess and analyze the effect of shade on the growth and production of upland red rice. The research was conducted using the quantitative method to obtain the optimal shading condition that can increase the rice anthocyanin content and relatively high production. The research was arranged in split plot design, with shade as main plot and the different of cultivar as sub plot with three replications. The shading treatment consist of 4 levels as follows: n1=shade level 75%. The cultivar tested were (v1) = Labandiri, (v2) = Jangkobembe, (v3) = Ranggohitam, and (v4) = Paedara. The rice planted in between teak wood trees with different age and level of canopy. The research reveals that shades had an effect in decreasing plant production (the higher level of shade, the higher the decrease level of production), but the shades can improve the quality of red rice through the increase of anthocyanin content.

  1. Cacao Cultivation under Diverse Shade Tree Cover Allows High Carbon Storage and Sequestration without Yield Losses.

    Science.gov (United States)

    Abou Rajab, Yasmin; Leuschner, Christoph; Barus, Henry; Tjoa, Aiyen; Hertel, Dietrich

    2016-01-01

    One of the main drivers of tropical forest loss is their conversion to oil palm, soy or cacao plantations with low biodiversity and greatly reduced carbon storage. Southeast Asian cacao plantations are often established under shade tree cover, but are later converted to non-shaded monocultures to avoid resource competition. We compared three co-occurring cacao cultivation systems (3 replicate stands each) with different shade intensity (non-shaded monoculture, cacao with the legume Gliricidia sepium shade trees, and cacao with several shade tree species) in Sulawesi (Indonesia) with respect to above- and belowground biomass and productivity, and cacao bean yield. Total biomass C stocks (above- and belowground) increased fivefold from the monoculture to the multi-shade tree system (from 11 to 57 Mg ha-1), total net primary production rose twofold (from 9 to 18 Mg C ha-1 yr-1). This increase was associated with a 6fold increase in aboveground biomass, but only a 3.5fold increase in root biomass, indicating a clear shift in C allocation to aboveground tree organs with increasing shade for both cacao and shade trees. Despite a canopy cover increase from 50 to 93%, cacao bean yield remained invariant across the systems (variation: 1.1-1.2 Mg C ha-1 yr-1). The monocultures had a twice as rapid leaf turnover suggesting that shading reduces the exposure of cacao to atmospheric drought, probably resulting in greater leaf longevity. Thus, contrary to general belief, cacao bean yield does not necessarily decrease under shading which seems to reduce physical stress. If planned properly, cacao plantations under a shade tree cover allow combining high yield with benefits for carbon sequestration and storage, production system stability under stress, and higher levels of animal and plant diversity.

  2. Modelling the canopy development of bambara groundnut

    DEFF Research Database (Denmark)

    Karunaratne, A.S.; Azam-Ali, S.N.; Al-Shareef, I.

    2010-01-01

    Canopy development of bambara groundnut (Vigna subterranea (L.) Verdc) is affected by temperature stress, drought stress and photoperiod. The quantification of these documented effects by means of a suitable crop model, BAMGRO is presented in this paper. Data on canopy development from five growth...... chamber, four glasshouse and three field experiments were analyzed to calibrate and validate the BAMGRO model to produce simulations for temperature stress, drought stress and photoperiodic effect on two contrasting landraces; Uniswa Red (Swaziland) and S19-3 (Namibia). The daily initiation rate of new...... leaves is calculated by means of a Gaussian function and is altered by temperature stress, drought stress, photoperiod and plant density. The rate in dead leaf number is dependent upon the maximum senescence fraction which can be explained by physiological maturity, mutual shading, temperature stress...

  3. Canopy Version 7.0: Canopy manual

    International Nuclear Information System (INIS)

    Fischler, M.; Uchima, M.; Hockney, G.; Mackenzie, P.

    1993-12-01

    Canopy provides a machine-independent environment for attacking grid-oriented problems. This document describes the concepts and routines common to all Canopy implementations, independent of the system and implementation. Information specific to the massively parallel ACPMAPS/indexACPMAPS system at FermiLab is contained in two other documents: The CANOPY ACPMAPS USER's GUIDE provides user-oriented instructions on compiling, running, file system usage, and production job control. The CANOPY ACPMAPS SYSTEM MANUAL describes system tools and installation and system management techniques. System-specific User's Guides may be created for implementations on other systems. The goal of Canopy is to allow scientists to use massively parallel systems for a broad class of applications without having to become expert in any particular system or in parallel programming techniques. The Canopy approach identifies grid-oriented concepts and implements them as routines in a library. Applications written in terms of these concepts will run on any system which supports the Canopy software. A side benefit in dealing with familiar concepts is that programs can more easily be understood by other researchers

  4. Influences of shading and fertilization on on-farm yields of cocoa in Ghana

    DEFF Research Database (Denmark)

    Richard, Asare; Asare, Rebecca Ashley; Asante, Winston Adams

    2017-01-01

    Most cocoa farms in Ghana are cultivated in complex agroforest systems, with plant growth and cocoa productivity being affected. The objective of this study was to investigate how shade trees affect cocoa yield, temperature and soil nutrients in low-input cocoa systems. Establishing plots on 24...... farms in four locations (districts) in Ghana, we assessed the influence of varying canopy cover and fertilization on cocoa yields. Results showed no relationship between canopy cover and cocoa yields in the light crop season (February to August). For the main crop season (September to January...... recorded in the cocoa canopies were above the recommended range for this species. Although shade trees had a slight modifying effect on peak temperatures, the magnitude appeared too small to have any practical effects....

  5. Environmental tolerance of an invasive riparian tree and its potential for continued spread in the southwestern US

    Science.gov (United States)

    Reynolds, L.V.; Cooper, D.J.

    2010-01-01

    Questions: Exotic plant invasion may be aided by facilitation and broad tolerance of environmental conditions, yet these processes are poorly understood in species-rich ecosystems such as riparian zones. In the southwestern United States (US) two plant species have invaded riparian zones: tamarisk (Tamarix ramosissima, T. chinensis, and their hybrids) and Russian olive (Elaeagnus angustifolia). We addressed the following questions: (1) is Russian olive able to tolerate drier and shadier conditions than cottonwood and tamarisk? (2) Can tamarisk and cottonwood facilitate Russian olive invasion? Location: Arid riparian zones, southwestern US. Methods: We analyzed riparian tree seedling requirements in a controlled experiment, performed empirical field studies, and analyzed stable oxygen isotopes to determine the water sources used by Russian olive. Results: Russian olive survival was significantly higher in dense shade and low moisture conditions than tamarisk and cottonwood. Field observations indicated Russian olive established where flooding cannot occur, and under dense canopies of tamarisk, cottonwood, and Russian olive. Tamarisk and native riparian plant species seedlings cannot establish in these dry, shaded habitats. Russian olive can rely on upper soil water until 15 years of age, before utilizing groundwater. Conclusions: We demonstrate that even though there is little evidence of facilitation by cottonwood and tamarisk, Russian olive is able to tolerate dense shade and low moisture conditions better than tamarisk and cottonwood. There is great potential for continued spread of Russian olive throughout the southwestern US because large areas of suitable habitat exist that are not yet inhabited by this species. ?? 2010 International Association for Vegetation Science.

  6. PowerShades. Transparent photovoltaics and solar shading. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Bezzel, E. (PhotoSolar ApS, Taastrup (Denmark)); Univ. of Neuchatel, Institute of Microtechnology, Neuchatel (CH)); Savcor Denmark A/S, Ballerup (Denmark)); Chem-Tec Plating A/S, Uldum (Denmark)); Danish Technological Institute (DTI), Taastrup (Denmark))

    2008-06-15

    This report marks the end of the PSO funded R and D project PowerShades. The objective of the project has been to establish knowledge about the manufacturing of PowerShade transparent photovoltaics and to demonstrate the viability of PowerShade, both as a product and when considered a building element. It has not been the objective to demonstrate a full-scale manufacturing of PowerShade, but to establish the knowledge that enables industrial manufacturing. The overall objective of the project has been achieved, and the large majority of the milestones defined have been met to full extent. It has been shown that PowerShade photovoltaic cells with an electrical efficiency of 5% can be reached, and it is expected that future work will lead to even better efficiency. Also, it has been demonstrated by full size side by side comparison that PowerShade transparent photovoltaics may replace exterior solar shading devices without compromise to the thermal properties of the building. The project has identified a number of work areas that must be addressed before an industrial manufacturing can be established. The efficiency of the photovoltaic generator must be increased and the stability of the entire product documented. Also, some of the identified processing steps must be scaled in capacity before manufacturing can be considered. (author)

  7. Shading decreases the abundance of the herbivorous California horn snail, Cerithidea californica

    Science.gov (United States)

    Lorda, Julio; Lafferty, Kevin D.

    2012-01-01

    Most of the intertidal zone in estuaries of California, USA and Baja California, Mexico is covered with vascular vegetation. Shading by these vascular plants influences abiotic and biotic processes that shape benthic community assemblages. We present data on the effects of shading on the California horn snail, Cerithidea californica. This species is important because it is the most common benthic macrofaunal species in these systems and acts as an obligate intermediate host of several species of rematode parasites that infect several other species. Using observational and experimental studies, we found a negative effect of shade on the distribution and abundance of the California horn snail. We hypothesized that shading reduces the abundance of the epipelic diatoms that the snails feeds on, causing snails to leave haded areas. We observed a negative relationship between vascular plant cover, sub-canopy light levels, and snail density in Mugu Lagoon. Then we experimentally manipulated light regimes, by clipping vegetation and adding shade structures, and found higher snail densities at higher light levels. In Goleta Slough, we isolated the effect of shade from vegetation by documenting a negative relationship between the shade created by two bridges and diatom and snail densities. We also found that snails moved the greatest distances over shaded channel banks compared to unshaded channel banks. Further, we documented the effect of water depth and channel bank orientation on shading in this system. An additional effect of shading is the reduction of temperature, providing an alternative explanation for some of our results. These results broaden our knowledge of how variation in the light environment influences the ecology of estuarine ecosystems.

  8. Canopy Chemistry (OTTER)

    Data.gov (United States)

    National Aeronautics and Space Administration — ABSTRACT: Canopy characteristics: leaf chemistry, specific leaf area, LAI, PAR, IPAR, NPP, standing biomass--see also: Meteorology (OTTER) for associated...

  9. Cooling and energy saving potentials of shade trees and urban lawns in a desert city

    International Nuclear Information System (INIS)

    Wang, Zhi-Hua; Zhao, Xiaoxi; Yang, Jiachuan; Song, Jiyun

    2016-01-01

    Highlights: • We developed a numerical framework incorporating trees in an urban canopy model. • Shade trees have more prominent energy saving potential than urban lawns. • The trade-off between water-energy is a key for urban landscape management. • Urban vegetation can significantly alleviate outdoor thermal stress. - Abstract: The use of urban vegetation in cities is a common landscape planning strategy to alleviate the heat island effect as well as to enhance building energy efficiency. The presence of trees in street canyons can effectively reduce environmental temperature via radiative shading. However, resolving shade trees in urban land surface models presents a major challenge in numerical models, especially in predicting the radiative heat exchange in canyons. In this paper, we develop a new numerical framework by incorporating shade trees into an advanced single-layer urban canopy model. This novel numerical framework is applied to Phoenix metropolitan area to investigate the cooling effect of different urban vegetation types and their potentials in saving building energy. It is found that the cooling effect by shading from trees is more significant than that by evapotranspiration from lawns, leading to a considerable saving of cooling load. In addition, analysis of human thermal comfort shows that urban vegetation plays a crucial role in creating a comfortable living environment, especially for cities located in arid or semi-arid region.

  10. Photochemical efficiency of PSII and photoprotective pigments in seedlings and adults of two Proteaceae with different shade tolerance from the Chilean temperate rain forest Eficiencia fotoquímica del PSII y pigmentos fotoprotectores en plántulas y adultos de dos Proteáceas con diferente tolerancia a la sombra del bosque lluvioso templado chileno

    Directory of Open Access Journals (Sweden)

    MIREN ALBERDI

    2009-01-01

    Full Text Available The seasonal variation in energy quenching parameters of photosystem II and photoprotective pigments were studied in seedlings and adults of two Proteaceae: a shade-intolerant species (Embotrium coccineum J.R. et G. Forster and a shade-tolerant species (Lomatia ferruginea (Cav. R. Br.. We postúlate that the shade intolerant species favors photochemical energy driven processes (mainly C0(2 assimilation while the shade tolerant species exhibits higher non-photochemical energy dissipation under unfavorable conditions. Moreover, the shade tolerant species presents lower seasonal variations in these parameters that the shade intolerant species. Differences in energy dissipation should be more evident in seedlings than adults because of their contrasting light environments and temperatures are more evident at this stage. Their maximal photochemical efficiency (Fv/Fm was in the range 0.70-0.83. The effective photochemical efficiency (PSII, photochemical quenching (qP, and electrón transport rate (ETR were higher in seedlings of E. coccineum than in seedlings of L. ferruginea. Adults showed higher photochemical energy quenching parameters than seedlings. Non-photochemical quenching (NPQ was frequently similar between daily periods, seasons, species, and developmental stages, with the exception of the lowest non-photochemical quenching in seedlings of E. coccineum in summer. Seedlings and adults showed a larger xanthophyll cycle pool contení at midday in summer than in winter, while the pool of antheraxanthin + zeaxanthin was always higher at midday. Lutein increased the most during summer. Thus, E. coccineum seedlings and adults maintained high photosynthesis, a higher fraction of open reaction centres, and higher ETR than the shade tolerant species. These differences are consistent with the ecological functions of both species: a pioneer character, higher growth rate, and wide altitudinal and latitudinal distribution of E. coccineum compared to L

  11. Potential phytotoxic and shading effects of invasive Fallopia (Polygonaceae) taxa on the germination of dominant native species

    Czech Academy of Sciences Publication Activity Database

    Moravcová, Lenka; Pyšek, Petr; Jarošík, Vojtěch; Zákravský, Petr

    2011-01-01

    Roč. 9, - (2011), s. 31-48 ISSN 1619-0033 R&D Projects: GA MŠk LC06073; GA AV ČR IAA6005805 Institutional research plan: CEZ:AV0Z60050516 Keywords : allelopathy * canopy shading * leaf and rhizom extracts Subject RIV: EF - Botanics

  12. Partial shading of Cabernet Sauvignon and Shiraz vines altered wine color and mouthfeel attributes, but increased exposure had little impact.

    Science.gov (United States)

    Joscelyne, Venetia L; Downey, Mark O; Mazza, Marica; Bastian, Susan E P

    2007-12-26

    Few studies have investigated the impact of vine shading on the sensory attributes of the resultant wine. This study examines the effects of canopy exposure levels on phenolic composition plus aroma, flavor, and mouthfeel aspects in wine. Wines were made from Cabernet Sauvignon and Shiraz grapes (Vitis vinifera L.) subjected to different levels of canopy exposure in a commercial vineyard in the Sunraysia region, Victoria, Australia. Canopy exposure treatments included control (standard vineyard practice), exposed (achieved with a foliage wire 600 mm above the top cordon), highly exposed (using a foliage wire with leaf plucking in the fruit zone), and shaded treatment (using 70% shade-cloth). Spectral and descriptive analyses showed that levels of anthocyanins, other phenolics, and perceived astringency were lower in wines made from shaded fruit; however, the reverse was generally not observed in wines of exposed and highly exposed fruit. Descriptive analysis also showed wines from the shaded fruit were different from other treatments for a number of flavor and aroma characters. These findings have implications for vineyard management practices.

  13. Interactions between canopy cover density and regeneration cores of older saplings in Scots pine (Pinus sylvestris L.) stands

    Energy Technology Data Exchange (ETDEWEB)

    Marchi, M.; Nocentini, S.; Ducci, F.

    2016-07-01

    Aim of the study: This paper provides an analysis of growth and survival of twenty–year–old Scots pine saplings in relation to canopy cover density (CCD) gradients, from dense (D–CCD), sparse (S–CCD), and gap (G–CCD) situations. Area of study: Aladag (Bolu) in northern Turkey. Material and methods: Sparse canopy cover density (S–CCD), dense canopy cover density (D–CCD) and gap canopy (G–CCD) were chosen within ten different strip sample plots (10 × 50 m) with sapling regeneration cores. Those regeneration cores were divided into two portions (individuals at the edge and middle of the regeneration cores) and from each portion three individuals was were obtained from a sample. The growth relationships of individual saplings were calculated with stem analyses. Honowski Light Factor (HLF) (ratio of Terminal sprout length (T) to Lateral sprout length (L)) was used to present growth potential measure of seedlings. Main results: The largest sapling regeneration cores were found in the G–CCD followed by S–CCD, and finally D–CCD, all tested for significance with Kruskal–Wallis Test. Compared with saplings in the middle of regeneration cores (crop saplings), those at the edge were always reduced in terms of mean height. Significant difference was only found between the ‘Main Crop’ and the ‘Edge 1’ of the regeneration cores for G–CCD suggesting that sapling regeneration cores are more typical under G–CCD conditions. HLF ratios were greater than 1 with high growth potentials for both CCD gradients (G–CCD and S–CCD) and there were no significant variations between G–CCD and S–CCD for main crop and edges. The thinning after 12–14 years increased sapling growth. However, under D–CCD, growth had virtually ceased. Research highlights: Naturally occurring Scots pine saplings are suppressed by a dense canopy. However, they are tolerant of shade to the extent that they can survive over relatively long time–periods (10–12 years) and

  14. Regeneration in bottomland forest canopy gaps 6 years after variable retention harvests to enhance wildlife habitat

    Science.gov (United States)

    Daniel J. Twedt; Scott G. Somershoe

    2013-01-01

    To promote desired forest conditions that enhance wildlife habitat in bottomland forests, managers prescribed and implemented variable-retention harvest, a.k.a. wildlife forestry, in four stands on Tensas River National Wildlife Refuge, LA. These treatments created canopy openings (gaps) within which managers sought to regenerate shade-intolerant trees. Six years after...

  15. Photosynthetic responses to understory shade and elevated carbon dioxide concentration in 4 northern hardwood tree species

    International Nuclear Information System (INIS)

    Sefcik, L.T.; Zak, D.R.; Ellsworth, D.S.

    2006-01-01

    Stimulation of photosynthesis in response to elevated carbon dioxide (CO 2 ) varies among tree species and species groups. In this study, seedling responses to elevated atmospheric carbon dioxide (CO 2 ) concentrations and solar irradiance over 2 growing seasons were investigated for shade tolerant Acer saccharum Marsh.; Fagus grandifolia J.F. Ehrh; and shade-intolerant Prunus serotina. Seedlings were exposed to a combination of elevated and ambient concentrations of CO 2 and understory shade in open-top chambers placed in a forest understory. It was observed that the elevated CO 2 treatment increased mean light-saturated net photosynthetic rates by 63 per cent in the shade-tolerant species and 67 per cent in the shade-intolerant species. When measured at the elevated CO 2 , long-term enhancement of photosynthesis was 10 per cent lower than the instantaneous enhancement observed in ambient-CO 2 -grown plants. As the growth irradiance increased, proportional enhancement due to elevated CO 2 decreased from 97 per cent for plants grown in deep shade to 47 per cent for plants grown in moderate shade. Results indicated that in nitrogen (N) limited northern temperate forests, trees grown in deep shade may display greater photosynthetic gains from a CO 2 enriched atmosphere than trees growing in more moderate shade, due to greater down-regulation. It was concluded that if elevated CO 2 levels promote the survival of shade-intolerant species in dim understory light, the future composition and dynamics of successional forest communities may be altered. 70 refs., 2 tabs., 3 figs

  16. Estimation of leaf area index for cotton canopies using the LI-COR LAI-2000 plant canopy analyzer

    International Nuclear Information System (INIS)

    Hicks, S.K.; Lascano, R.J.

    1995-01-01

    Measurement of leaf area index (LAI) is useful for understanding cotton (Gossypium hirsutum L.) growth, water use, and canopy light interception. Destructive measurement is time consuming and labor intensive. Our objective was to evaluate sampling procedures using the Li-Cor (Lincoln, NE) LAI 2000 plant canopy analyzer (PCA) for nondestructive estimation of cotton LAI on the southern High Plains of Texas. We evaluated shading as a way to allow PCA measurements in direct sunlight and the influence of solar direction when using this procedure. We also evaluated a test of canopy homogeneity (information required for setting PCA field of view), determined the number of below-canopy measurements required, examined the influence of leaf wilting on PCA LAI determinations, and tested an alternative method (masking the sensor's two outer rings) for calculating LAI from PCA measurements. The best agreement between PCA and destructively measured LAI values was obtained when PCA observations were made either during uniformly overcast conditions or around solar noon using the shading method. Heterogeneous canopies with large gaps between rows required both a restricted (45 degrees) azimuthal field of view and averaging the LAI values for two transects, made with the field of view parallel and then perpendicular to the row direction. This method agreed well (r2 = 0.84) with destructively measured LAI in the range of 0.5 to 3.5 and did not deviate from a 1:1 relationship. The PCA underestimated LAI by greater than or equal 20% when measurements were made on canopies wilted due to water stress. Masking the PCA sensor's outer rings did not improve the relationship between estimated and measured LAI in the range of LAI sampled

  17. Effects of shading on relative competitive advantage of three species of Sphagnum

    Directory of Open Access Journals (Sweden)

    J.Z. Ma

    2015-06-01

    Full Text Available (1 Sphagnum is an important genus of bryophytes holding 10–15 % of the terrestrial carbon stock. With climate change a drier surface may increase the abundance of vascular plants on peatlands, so shading of Sphagnum may increase. Here we describe growth cabinet experiments to reveal the effects of shading on interactions among mixtures of three species: S. capillifolium, S. palustre (hummock species, and S. fallax (a hollow species. We measured the six traits: growth in length, growth as increase in dry mass, side-shoot production, nitrogen and carbon proportion of the capitulum dry mass, and C:N ratio in the capitulum. (2 Shading had no effect on biomass production or side-shoot production but increased height increment in all three species. It also increased the C and N proportions of total dry mass but decreased C:N ratio in the capitula. (3 Neighbours of a different species reduced biomass and side-shoot production in the two hummock species but had no effect on the hollow species. (4 All three species showed interaction between shading and neighbour in two or more plant traits. S. fallax showed competitive advantage over S. palustre in no-shading treatments and over S. capillifolium in moderate shading treatments. In addition, under deep shading, S. fallax showed a competitive advantage over both hummock species. A clear competitive hierarchy S. fallax>S. capillifolium>S. palustre emerged which was consistent with the hierarchy of side-shoot production. (5 The results suggest that all the species appear to tolerate deep shade (for a few months at least. In a shaded environment, especially under deeply shaded conditions, S. fallax retains its dominance in hollow habitats (if water availability is guaranteed by virtue of its advantage in side-shoot production. (6 If shading increases then the abundance of different Sphagnum species is likely to change.

  18. Net herbage accumulation rate and crude protein content of Urochloa brizantha cultivars under shade intensities

    OpenAIRE

    Paulo Roberto de Lima Meirelles; Erikelly Aline Ribeiro de Santana; Guilherme Mendes Machado Franco de Arruda; Ciniro Costa; Marina Gabriela Berchiol da Silva

    2013-01-01

    The use of silvopastoral systems is a sustainable alternative for animal production in various regions of the Brazil. However to obtain satisfactory results in these systems, the selection of forage species that grows well in the shade should be done. The tolerance of plants to light restriction and the correctly choice of species, considering good nutritional values for these conditions has great importance. The study of artificial shading for forage production helps the clarification of iss...

  19. Growth characteristics and nutrient content of some herbaceous species under shade and fertilization

    Energy Technology Data Exchange (ETDEWEB)

    Koukoura, Z.; Kyriazopoulos, A. P.; Parissi, Z. M.

    2009-07-01

    Herbage production and nutrient content are affected by light interception and soil fertility. The objective of this study was to assess the effects of artificial shade and fertilization on herbage production, growth characteristics, and nutrient content of the grass species Dactylis glomerata and Festuca ovina, and the legume species Trifolium subterraneum and Medicago lupulina. Each plant species was placed under three shading treatments of 90% (heavy shade), 50% (moderate shade) and 0% (control). Fertilization (225 kg ha{sup -}1 N, 450 kg ha{sup -}1 P, and 225 kg ha{sup -}1 K) was applied to half of the pots of every species and shading treatment. Reduced light intensity (90% shading) significantly lowered herbage production from 18% for F. ovina to 48% for D. glomerata and decreased the root:shoot (R/S) ratio of all species but the moderate reduction of light intensity (50%) did not affect R/S ratio and herbage production of the grasses and M. lupulina, while it resulted in an increase of the production of T. subterraneum by 10.5%. Reduced light intensity increased by 25% on average, the crude protein concentration of the grass species while moderate shading did not affect the crude protein concentration of T. subterraneum. Fertilization increased herbage production from 16% for F. ovina to 59% for D. glomerata and ameliorated its nutrient content. Among the tested species, D. glomerata and T. subterraneum demonstrated the highest shade tolerance and could be incorporated into silvopastoral systems of the Mediterranean region. (Author)

  20. NLCD 2001 - Tree Canopy

    Data.gov (United States)

    Minnesota Department of Natural Resources — The National Land Cover Database 2001 tree canopy layer for Minnesota (mapping zones 39-42, 50-51) was produced through a cooperative project conducted by the...

  1. Efficient Methods for Fast Shading

    Directory of Open Access Journals (Sweden)

    ROMANYUK, A.

    2008-06-01

    Full Text Available On devices without battery consuming and specialized hardware for rendering, it is important to improve the speed and quality so that these methods are suitable for real-time rendering. Furthermore such algorithms are needed on the coming multicore architectures. We show how the methods by Gouraud and Phong, the commonly most used methods for shading, can be improved and made faster for both software rendering as well as simple low energy consuming hardware implementations. Moreover, this paper summarizes the authors' achievements in increasing shading speed and performance and a Bidirectional Reflectance Distribution Function is simplified for faster computing and hardware implementation.

  2. The Relationship between On-Farm Shade Trees and Cocoa Yields in Ghana

    DEFF Research Database (Denmark)

    Asare, Richard

    Cocoa (Theobroma cacao L.) is a crop that is widely cultivated across West Africa with Côte d’Ivoire, Cameroon, Ghana and Nigeria contributing about 70% of the global production. In Ghana cocoa contributes significantly to the national economy as over 20% of the world’s cocoa production comes from...... the country, making it the world’s second largest producer with an annual production level of over 700,000 metric tons, and an estimated cultivation area of ca. 1.6 million ha. Cocoa is mostly cultivated by smallholder farmers either as a monocrop or in association with other food crops, tree crops and under...... the cover of shade trees – cocoa agroforestry. This thesis hypothesizes that canopy cover of shade trees in low input (low-to-no fertilizer application) cocoa growing systems can contribute to cocoa yield improvements. The main theme deals with shade trees diversity and its effects on cocoa production...

  3. Impact of shade on outdoor thermal comfort—a seasonal field study in Tempe, Arizona

    Science.gov (United States)

    Middel, Ariane; Selover, Nancy; Hagen, Björn; Chhetri, Nalini

    2016-12-01

    Shade plays an important role in designing pedestrian-friendly outdoor spaces in hot desert cities. This study investigates the impact of photovoltaic canopy shade and tree shade on thermal comfort through meteorological observations and field surveys at a pedestrian mall on Arizona State University's Tempe campus. During the course of 1 year, on selected clear calm days representative of each season, we conducted hourly meteorological transects from 7:00 a.m. to 6:00 p.m. and surveyed 1284 people about their thermal perception, comfort, and preferences. Shade lowered thermal sensation votes by approximately 1 point on a semantic differential 9-point scale, increasing thermal comfort in all seasons except winter. Shade type (tree or solar canopy) did not significantly impact perceived comfort, suggesting that artificial and natural shades are equally efficient in hot dry climates. Globe temperature explained 51 % of the variance in thermal sensation votes and was the only statistically significant meteorological predictor. Important non-meteorological factors included adaptation, thermal comfort vote, thermal preference, gender, season, and time of day. A regression of subjective thermal sensation on physiological equivalent temperature yielded a neutral temperature of 28.6 °C. The acceptable comfort range was 19.1 °C-38.1 °C with a preferred temperature of 20.8 °C. Respondents exposed to above neutral temperature felt more comfortable if they had been in air-conditioning 5 min prior to the survey, indicating a lagged response to outdoor conditions. Our study highlights the importance of active solar access management in hot urban areas to reduce thermal stress.

  4. Impact of shade on outdoor thermal comfort-a seasonal field study in Tempe, Arizona.

    Science.gov (United States)

    Middel, Ariane; Selover, Nancy; Hagen, Björn; Chhetri, Nalini

    2016-12-01

    Shade plays an important role in designing pedestrian-friendly outdoor spaces in hot desert cities. This study investigates the impact of photovoltaic canopy shade and tree shade on thermal comfort through meteorological observations and field surveys at a pedestrian mall on Arizona State University's Tempe campus. During the course of 1 year, on selected clear calm days representative of each season, we conducted hourly meteorological transects from 7:00 a.m. to 6:00 p.m. and surveyed 1284 people about their thermal perception, comfort, and preferences. Shade lowered thermal sensation votes by approximately 1 point on a semantic differential 9-point scale, increasing thermal comfort in all seasons except winter. Shade type (tree or solar canopy) did not significantly impact perceived comfort, suggesting that artificial and natural shades are equally efficient in hot dry climates. Globe temperature explained 51 % of the variance in thermal sensation votes and was the only statistically significant meteorological predictor. Important non-meteorological factors included adaptation, thermal comfort vote, thermal preference, gender, season, and time of day. A regression of subjective thermal sensation on physiological equivalent temperature yielded a neutral temperature of 28.6 °C. The acceptable comfort range was 19.1 °C-38.1 °C with a preferred temperature of 20.8 °C. Respondents exposed to above neutral temperature felt more comfortable if they had been in air-conditioning 5 min prior to the survey, indicating a lagged response to outdoor conditions. Our study highlights the importance of active solar access management in hot urban areas to reduce thermal stress.

  5. Impact of Vertical Canopy Position on Leaf Spectral Properties and Traits across Multiple Species

    Directory of Open Access Journals (Sweden)

    Tawanda W. Gara

    2018-02-01

    Full Text Available Understanding the vertical pattern of leaf traits across plant canopies provide critical information on plant physiology, ecosystem functioning and structure and vegetation response to climate change. However, the impact of vertical canopy position on leaf spectral properties and subsequently leaf traits across the entire spectrum for multiple species is poorly understood. In this study, we examined the ability of leaf optical properties to track variability in leaf traits across the vertical canopy profile using Partial Least Square Discriminatory Analysis (PLS-DA. Leaf spectral measurements together with leaf traits (nitrogen, carbon, chlorophyll, equivalent water thickness and specific leaf area were studied at three vertical canopy positions along the plant stem: lower, middle and upper. We observed that foliar nitrogen (N, chlorophyll (Cab, carbon (C, and equivalent water thickness (EWT were higher in the upper canopy leaves compared with lower shaded leaves, while specific leaf area (SLA increased from upper to lower canopy leaves. We found that leaf spectral reflectance significantly (P ≤ 0.05 shifted to longer wavelengths in the ‘red edge’ spectrum (685–701 nm in the order of lower > middle > upper for the pooled dataset. We report that spectral bands that are influential in the discrimination of leaf samples into the three groups of canopy position, based on the PLS-DA variable importance projection (VIP score, match with wavelength regions of foliar traits observed to vary across the canopy vertical profile. This observation demonstrated that both leaf traits and leaf reflectance co-vary across the vertical canopy profile in multiple species. We conclude that canopy vertical position has a significant impact on leaf spectral properties of an individual plant’s traits, and this finding holds for multiple species. These findings have important implications on field sampling protocols, upscaling leaf traits to canopy level

  6. Esthetics and shade communication: a practical approach.

    Science.gov (United States)

    Hegenbarth, Ernst A

    2006-01-01

    Accurate shade analysis and communication represent one of the biggest challenges in restorative and esthetic dentistry today, especially in light of the rapidly increasing array of ceramic materials available. Traditional methods of shade analysis have relied upon the use of conventional shade guides or, more recently, digital shade measurement. In this article, the author examines the advantages and disadvantages of traditional shade analysis; reviews principles for optimizing the evaluation process, including information regarding the scientific basis of general color science, optics, and aspects of material science; and proposes a six-step approach to shade analysis in which less emphasis is placed on shade guide samples in favor of natural internal structures and surface properties and their replication in different dentin, enamel, transparent, and colored translucent, as well as fluorescent and opalescent, ceramics.

  7. Regeneration in bottomland forest canopy gaps six years after variable retention harvests to enhance wildlife habitat

    Science.gov (United States)

    Twedt, Daniel J.; Somershoe, Scott G.; Guldin, James M.

    2013-01-01

    To promote desired forest conditions that enhance wildlife habitat in bottomland forests, managers prescribed and implemented variable-retention harvest, a.k.a. wildlife forestry, in four stands on Tensas River National Wildlife Refuge, LA. These treatments created canopy openings (gaps) within which managers sought to regenerate shade-intolerant trees. Six years after prescribed harvests, we assessed regeneration in 41 canopy gaps and 4 large (>0.5-ha) patch cut openings that resulted from treatments and in 21 natural canopy gaps on 2 unharvested control stands. Mean gap area of anthropogenic gaps (582 m²) was greater than that of natural gaps (262 m²). Sweetgum (Liquidambar styraciflua) and red oaks (Quercus nigra, Q. nuttallii, and Q. phellos) were common in anthropogenic gaps, whereas elms (Ulmus spp.) and sugarberry (Celtis laevigata) were numerous in natural gaps. We recommend harvest prescriptions include gaps with diameter >25 m, because the proportion of shade-intolerant regeneration increased with gap area up to 500 m². The proportion of shade-intolerant definitive gap fillers (individuals likely to occupy the canopy) increased with gap area: 35 percent in natural gaps, 54 percent in anthropogenic gaps, and 84 percent in patch cuts. Sweetgum, green ash (Fraxinus pennsylvanica), and red oaks were common definitive gap fillers.

  8. Shade tree diversity, cocoa pest damage, yield compensating inputs and farmers' net returns in West Africa.

    Directory of Open Access Journals (Sweden)

    Hervé Bertin Bisseleua Daghela

    Full Text Available Cocoa agroforests can significantly support biodiversity, yet intensification of farming practices is degrading agroforestry habitats and compromising ecosystem services such as biological pest control. Effective conservation strategies depend on the type of relationship between agricultural matrix, biodiversity and ecosystem services, but to date the shape of this relationship is unknown. We linked shade index calculated from eight vegetation variables, with insect pests and beneficial insects (ants, wasps and spiders in 20 cocoa agroforests differing in woody and herbaceous vegetation diversity. We measured herbivory and predatory rates, and quantified resulting increases in cocoa yield and net returns. We found that number of spider webs and wasp nests significantly decreased with increasing density of exotic shade tree species. Greater species richness of native shade tree species was associated with a higher number of wasp nests and spider webs while species richness of understory plants did not have a strong impact on these beneficial species. Species richness of ants, wasp nests and spider webs peaked at higher levels of plant species richness. The number of herbivore species (mirid bugs and cocoa pod borers and the rate of herbivory on cocoa pods decreased with increasing shade index. Shade index was negatively related to yield, with yield significantly higher at shade and herb covers<50%. However, higher inputs in the cocoa farms do not necessarily result in a higher net return. In conclusion, our study shows the importance of a diverse shade canopy in reducing damage caused by cocoa pests. It also highlights the importance of conservation initiatives in tropical agroforestry landscapes.

  9. Color Parameters of the Chromascop Shade Guide

    Directory of Open Access Journals (Sweden)

    William J. O'Brien

    2012-12-01

    Full Text Available The purposes of this study are: (1 determine the color of the twenty shades in the Ivoclar’s Chromascop shade guide, (2 determine the color representation of the shade guide described as coverage error (CE, and (3 compare this shade guide with the Vita Classical and Bioform shade guides. The spectral data was collected using Beckman model DU reflectance spectrophotometer equipped with an integrating sphere. Commission International de l’Eclairage (CIE chromaticity coordinates were calculated using CIE illuminant C and 1931 observer data, then converted to CIE L*a*b* and Munsell notation. Each shade was spectrophotometrically compared to the published colors of 335 human teeth. The minimum CIE L*a*b* color difference was calculated for each tooth and the average of these color differences was defined as the CE. The measured colors of the Chromascop guide had a CIE L* range of 79.67 to 65.61, an a* range of -0.71 to 3.85, and a b* range of 14.58 to 27.69. The average CE of the Chromascop shade guide was 3.38. The Chromascop shade guide has similar colors and a CE compared with the Bioform and Vita Classical shade guides, but with some shades of higher red and yellow components.

  10. Shade determination using camouflaged visual shade guides and an electronic spectrophotometer.

    Science.gov (United States)

    Kvalheim, S F; Øilo, M

    2014-03-01

    The aim of the present study was to compare a camouflaged visual shade guide to a spectrophotometer designed for restorative dentistry. Two operators performed analyses of 66 subjects. One central upper incisor was measured four times by each operator; twice with a camouflaged visual shade guide and twice with a spectrophotometer Both methods had acceptable repeatability rates, but the electronic shade determination showed higher repeatability. In general, the electronically determined shades were darker than the visually determined shades. The use of a camouflaged visual shade guide seems to be an adequate method to reduce operator bias.

  11. Canopy accession patterns of table mountain and pitch pines during the 19th and 20th centuries

    Science.gov (United States)

    Patrick H. Brose; Thomas A. Waldrop

    2012-01-01

    A dendrochronology study was conducted in three upland yellow pine stands in Georgia to determine whether the individual Table Mountain (Pinus pungens) and pitch (P. rigida) pines originated in sunny gaps or shaded understories, whether they grew uninterrupted into the canopy or were assisted by one or more releases, and whether...

  12. Response of reptile and amphibian communities to canopy gaps created by wind disturbance in the Southern Appalachians

    Science.gov (United States)

    Cathryn H. Greenberg

    2001-01-01

    Reptile and amphibian communities were sampled in intact gaps created by wind disturbance, salvage-logged gaps, and closed canopy mature forest (controls). Sampling was conducted during June–October in 1997 and 1998 using drift fences with pitfall and funnel traps. Basal area of live trees, shade, leaf litter coverage, and litter depth was highest in controls and...

  13. Making biodiversity-friendly cocoa pay: combining yield, certification, and REDD for shade management.

    Science.gov (United States)

    Waldron, A; Justicia, R; Smith, L E

    2015-03-01

    The twin United Nations' Millennium Development Goals of biodiversity preservation and poverty reduction both strongly depend on actions in the tropics. In particular, traditional agroforestry could be critical to both biological conservation and human livelihoods in human-altered rainforest areas. However, traditional agroforestry is rapidly disappearing, because the system itself is economically precarious, and because the forest trees that shade traditional crops are now perceived to be overly detrimental to agricultural yield. Here, we show a case where the commonly used agroforestry shade metric, canopy cover, would indeed suggest complete removal of shade trees to maximize yield, with strongly negative biodiversity and climate implications. However, a yield over 50% higher was achievable if approximately 100 shade trees per hectare were planted in a spatially organized fashion, a win-win for biodiversity and the smallholder. The higher yield option was detected by optimizing simultaneously for canopy cover, and a second shade metric, neighboring tree density, which was designed to better capture the yield value of ecological services flowing from forest trees. Nevertheless, even a 50% yield increase may prove insufficient to stop farmers converting away from traditional agroforestry. To further increase agroforestry rents, we apply our results to the design of a sustainable certification (eco-labelling) scheme for cocoa-based products in a biodiversity hotspot, and consider their implications for the use of the United Nations REDD (reducing emissions from deforestation and forest degradation) program in agroforestry systems. Combining yield boost, certification, and REDD has the potential to incentivize eco-friendly agroforestry and lift smallholders out of poverty, simultaneously.

  14. Reconciling leaf physiological traits and canopy flux data: Use of the TRY and FLUXNET databases in the Community Land Model version 4

    Science.gov (United States)

    Bonan, Gordon B.; Oleson, Keith W.; Fisher, Rosie A.; Lasslop, Gitta; Reichstein, Markus

    2012-06-01

    The Community Land Model version 4 overestimates gross primary production (GPP) compared with estimates from FLUXNET eddy covariance towers. The revised model of Bonan et al. (2011) is consistent with FLUXNET, but values for the leaf-level photosynthetic parameterVcmaxthat yield realistic GPP at the canopy-scale are lower than observed in the global synthesis of Kattge et al. (2009), except for tropical broadleaf evergreen trees. We investigate this discrepancy betweenVcmaxand canopy fluxes. A multilayer model with explicit calculation of light absorption and photosynthesis for sunlit and shaded leaves at depths in the canopy gives insight to the scale mismatch between leaf and canopy. We evaluate the model with light-response curves at individual FLUXNET towers and with empirically upscaled annual GPP. Biases in the multilayer canopy with observedVcmaxare similar, or improved, compared with the standard two-leaf canopy and its lowVcmax, though the Amazon is an exception. The difference relates to light absorption by shaded leaves in the two-leaf canopy, and resulting higher photosynthesis when the canopy scaling parameterKn is low, but observationally constrained. Larger Kndecreases shaded leaf photosynthesis and reduces the difference between the two-leaf and multilayer canopies. The low modelVcmaxis diagnosed from nitrogen reduction of GPP in simulations with carbon-nitrogen biogeochemistry. Our results show that the imposed nitrogen reduction compensates for deficiency in the two-leaf canopy that produces high GPP. Leaf trait databases (Vcmax), within-canopy profiles of photosynthetic capacity (Kn), tower fluxes, and empirically upscaled fields provide important complementary information for model evaluation.

  15. Influence of Forest-Canopy Morphology and Relief on Spectral Characteristics of Taiga Forests

    Science.gov (United States)

    Zhirin, V. M.; Knyazeva, S. V.; Eydlina, S. P.

    2017-12-01

    The article deals with the results of a statistical analysis reflecting tendencies (trends) of the relationship between spectral characteristics of taiga forests, indicators of the morphological structure of forest canopy and illumination of the territory. The study was carried out on the example of the model forest territory of the Priangarskiy taiga region of Eastern Siberia (Krasnoyarsk krai) using historical data (forest inventory 1992, Landsat 5 TM 16.06.1989) and the digital elevation model. This article describes a method for determining the quantitative indicator of morphological structure of forest canopy based on taxation data, and the authors propose to subdivide the morphological structure into high complexity, medium complexity, and relatively simple. As a result of the research, dependences of average values of spectral brightness in near and short-wave infrared channels of a Landsat 5 TM image for dark-coniferous, light-coniferous and deciduous forests from the degree of complexity of the forest-canopy structure are received. A high level of variance and maximum brightness average values are marked in green moss (hilocominosa) dark-coniferous and various-grass (larioherbosa) dark-coniferous forests and light-coniferous forests with a complex structure of canopy. The parvifoliate forests are characterized by high values of brightness in stands with a relatively simple structure of the canopy and by a small variance in brightness of any degree of the structure of the canopy complexity. The increase in brightness for the lit slopes in comparison with shaded ones in all stands with a difficult morphological canopy structure is revealed. However, the brightness values of the lit and shaded slopes do not differ for stands with a medium complexity of the structure. It is noted that, in addition to the indicator of the forest-canopy structure, the possible impact on increasing the variance of spectral brightness for the taxation plot has a variability of the

  16. Turbulent flows over sparse canopies

    Science.gov (United States)

    Sharma, Akshath; García-Mayoral, Ricardo

    2018-04-01

    Turbulent flows over sparse and dense canopies exerting a similar drag force on the flow are investigated using Direct Numerical Simulations. The dense canopies are modelled using a homogeneous drag force, while for the sparse canopy, the geometry of the canopy elements is represented. It is found that on using the friction velocity based on the local shear at each height, the streamwise velocity fluctuations and the Reynolds stress within the sparse canopy are similar to those from a comparable smooth-wall case. In addition, when scaled with the local friction velocity, the intensity of the off-wall peak in the streamwise vorticity for sparse canopies also recovers a value similar to a smooth-wall. This indicates that the sparse canopy does not significantly disturb the near-wall turbulence cycle, but causes its rescaling to an intensity consistent with a lower friction velocity within the canopy. In comparison, the dense canopy is found to have a higher damping effect on the turbulent fluctuations. For the case of the sparse canopy, a peak in the spectral energy density of the wall-normal velocity, and Reynolds stress is observed, which may indicate the formation of Kelvin-Helmholtz-like instabilities. It is also found that a sparse canopy is better modelled by a homogeneous drag applied on the mean flow alone, and not the turbulent fluctuations.

  17. What is the most prominent factor limiting photosynthesis in different layers of a greenhouse cucumber canopy?

    Science.gov (United States)

    Chen, Tsu-Wei; Henke, Michael; de Visser, Pieter H B; Buck-Sorlin, Gerhard; Wiechers, Dirk; Kahlen, Katrin; Stützel, Hartmut

    2014-09-01

    Maximizing photosynthesis at the canopy level is important for enhancing crop yield, and this requires insights into the limiting factors of photosynthesis. Using greenhouse cucumber (Cucumis sativus) as an example, this study provides a novel approach to quantify different components of photosynthetic limitations at the leaf level and to upscale these limitations to different canopy layers and the whole plant. A static virtual three-dimensional canopy structure was constructed using digitized plant data in GroIMP. Light interception of the leaves was simulated by a ray-tracer and used to compute leaf photosynthesis. Different components of photosynthetic limitations, namely stomatal (S(L)), mesophyll (M(L)), biochemical (B(L)) and light (L(L)) limitations, were calculated by a quantitative limitation analysis of photosynthesis under different light regimes. In the virtual cucumber canopy, B(L) and L(L) were the most prominent factors limiting whole-plant photosynthesis. Diffusional limitations (S(L) + M(L)) contributed Photosynthesis in the lower canopy was more limited by the biochemical capacity, and the upper canopy was more sensitive to light than other canopy parts. Although leaves in the upper canopy received more light, their photosynthesis was more light restricted than in the leaves of the lower canopy, especially when the light condition above the canopy was poor. An increase in whole-plant photosynthesis under diffuse light did not result from an improvement of light use efficiency but from an increase in light interception. Diffuse light increased the photosynthesis of leaves that were directly shaded by other leaves in the canopy by up to 55%. Based on the results, maintaining biochemical capacity of the middle-lower canopy and increasing the leaf area of the upper canopy would be promising strategies to improve canopy photosynthesis in a high-wire cucumber cropping system. Further analyses using the approach described in this study can be expected to

  18. Modeling canopy-level productivity: is the "big-leaf" simplification acceptable?

    Science.gov (United States)

    Sprintsin, M.; Chen, J. M.

    2009-05-01

    The "big-leaf" approach to calculating the carbon balance of plant canopies assumes that canopy carbon fluxes have the same relative responses to the environment as any single unshaded leaf in the upper canopy. Widely used light use efficiency models are essentially simplified versions of the big-leaf model. Despite its wide acceptance, subsequent developments in the modeling of leaf photosynthesis and measurements of canopy physiology have brought into question the assumptions behind this approach showing that big leaf approximation is inadequate for simulating canopy photosynthesis because of the additional leaf internal control on carbon assimilation and because of the non-linear response of photosynthesis on leaf nitrogen and absorbed light, and changes in leaf microenvironment with canopy depth. To avoid this problem a sunlit/shaded leaf separation approach, within which the vegetation is treated as two big leaves under different illumination conditions, is gradually replacing the "big-leaf" strategy, for applications at local and regional scales. Such separation is now widely accepted as a more accurate and physiologically based approach for modeling canopy photosynthesis. Here we compare both strategies for Gross Primary Production (GPP) modeling using the Boreal Ecosystem Productivity Simulator (BEPS) at local (tower footprint) scale for different land cover types spread over North America: two broadleaf forests (Harvard, Massachusetts and Missouri Ozark, Missouri); two coniferous forests (Howland, Maine and Old Black Spruce, Saskatchewan); Lost Creek shrubland site (Wisconsin) and Mer Bleue petland (Ontario). BEPS calculates carbon fixation by scaling Farquhar's leaf biochemical model up to canopy level with stomatal conductance estimated by a modified version of the Ball-Woodrow-Berry model. The "big-leaf" approach was parameterized using derived leaf level parameters scaled up to canopy level by means of Leaf Area Index. The influence of sunlit/shaded

  19. Shading Ratio Impact on Photovoltaic Modules and Correlation with Shading Patterns

    Directory of Open Access Journals (Sweden)

    Alonso Gutiérrez Galeano

    2018-04-01

    Full Text Available This paper presents the study of a simplified approach to model and analyze the performance of partially shaded photovoltaic modules using the shading ratio. This approach integrates the characteristics of shaded area and shadow opacity into the photovoltaic cell model. The studied methodology is intended to improve the description of shaded photovoltaic systems by specifying an experimental procedure to quantify the shadow impact. Furthermore, with the help of image processing, the analysis of the shading ratio provides a set of rules useful for predicting the current–voltage behavior and the maximum power points of shaded photovoltaic modules. This correlation of the shading ratio and shading patterns can contribute to the supervision of actual photovoltaic installations. The experimental results validate the proposed approach in monocrystalline and polycrystalline technologies of solar panels.

  20. External shading devices for energy efficient building

    Science.gov (United States)

    Shahdan, M. S.; Ahmad, S. S.; Hussin, M. A.

    2018-02-01

    External shading devices on a building façade is an important passive design strategy as they reduce solar radiation. Although studies have proven the benefits of external shading devices, many are designed solely for aesthetic purposes without fully considering its high potential to reduce solar radiation and glare. Furthermore, explorations into shading devices by the design team are mostly left too late in the design development phases. Hence, the paper looks into the effectiveness of external shading devices on a building towards more energy efficient building. The study aims to analyse the effects of various configurations of external shading devices towards the energy consumption of a case study building based on computer simulations. This study uses Building Information Modelling (BIM) through Autodesk Revit software as simulation tool. The constant variables for the simulation are the orientation of the building, types of glazing used by the building and the internal loads of the building. Whereas, the manipulated variable is the types of shading device used. The data were sorted according to the categories and translated into a chart. Analysis of the findings indicate that shading devices with different configurations show significant results in the energy consumption and the best configuration is the egg-crate shading devices. The study recommends that the consideration for shading device as a passive design strategy needs to be developed at the early stage of the building design.

  1. Effects of structural complexity on within-canopy light environments and leaf traits in a northern mixed deciduous forest.

    Science.gov (United States)

    Fotis, Alexander T; Curtis, Peter S

    2017-10-01

    Canopy structure influences forest productivity through its effects on the distribution of radiation and the light-induced changes in leaf physiological traits. Due to the difficulty of accessing and measuring forest canopies, few field-based studies have quantitatively linked these divergent scales of canopy functioning. The objective of our study was to investigate how canopy structure affects light profiles within a forest canopy and whether leaves of mature trees adjust morphologically and biochemically to the light environments characteristic of canopies with different structural complexity. We used a combination of light detection and ranging (LiDAR) data and hemispherical photographs to quantify canopy structure and light environments, respectively, and a telescoping pole to sample leaves. Leaf mass per area (LMA), nitrogen on an area basis (Narea) and chlorophyll on a mass basis (Chlmass) were measured in red maple (Acer rubrum), american beech (Fagus grandifolia), white pine (Pinus strobus), and northern red oak (Quercus rubra) at different heights in plots with similar leaf area index but contrasting canopy complexity (rugosity). We found that more complex canopies had greater porosity and reduced light variability in the midcanopy while total light interception was unchanged relative to less complex canopies. Leaf phenotypes of F. grandifolia, Q. rubra and P. strobus were more sun-acclimated in the midstory of structurally complex canopies while leaf phenotypes of A. rubrum were more shade-acclimated (lower LMA) in the upper canopy of more complex stands, despite no differences in total light interception. Broadleaf species showed further differences in acclimation with increased Narea and reduced Chlmass in leaves with higher LMA, while P. strobus showed no change in Narea and Chlmass with higher LMA. Our results provide new insight on how light distribution and leaf acclimation in mature trees might be altered when natural and anthropogenic

  2. Photosynthetic response of Eriophorum vaginatum to in situ shrub shading in tussock tundra of northern Alaska

    Science.gov (United States)

    Anderson-Smith, A.; Pattison, R.; Sullivan, P.; Welker, J. M.

    2009-12-01

    Eriophorum vaginatum (Cotton Grass) is an important component of moist acidic tussock tundra, a plant community that appears to be undergoing changes in species composition associated with climate warming. This species is one of the most abundant in the arctic tundra, and provides important forage for caribou in their calving grounds on the Arctic Coastal Plain and along their migratory route through the foothills of Alaska. Recently, remote sensing data, repeat photography and plot-level measurements have indicated that shrub abundance is increasing while Eriophorum abundance is either constant or decreasing. One possible explanation for the reduction of Eriophorum while Betula nana is increasing, is that lower light levels in the taller Betula canopy may be constraining Eriophorum photosynthesis and subsequently reducing plant growth. This study measured the effect of shading on the light response of Eriphorum leaf photosynthesis in four different sites near Toolik Lake Alaska during the summer of 2009. Measurements were taken in: 1) a shrub patch within the drift zone of the ITEX long term snow fence experiment, 2) an LTER shade house (50% shading) built in 1989, 3) water track site 1 and water track site 2 (i.e. control areas with no experimental manipulations) Average photosynthetic rates for Eriophorum at a light level of 800 PAR varied from 3.8 to 10.9 umol m-2 s-1 and were not significantly different in shaded and unshaded areas. This study indicates that shading by shrubs does not appear to be altering the light response of Eriophorum nor does long-term shading by itself eliminate Eriophorum from the community. An alternative explanation for the decline of Eriophorum while Betula increases in abundance under changing climates may be related to plant and soil mineral nutrition, plant water relations or biotic processes involving herbivores.

  3. Basking behavior predicts the evolution of heat tolerance in Australian rainforest lizards.

    Science.gov (United States)

    Muñoz, Martha M; Langham, Gary M; Brandley, Matthew C; Rosauer, Dan F; Williams, Stephen E; Moritz, Craig

    2016-11-01

    There is pressing urgency to understand how tropical ectotherms can behaviorally and physiologically respond to climate warming. We examine how basking behavior and thermal environment interact to influence evolutionary variation in thermal physiology of multiple species of lygosomine rainforest skinks from the Wet Tropics of northeastern Queensland, Australia (AWT). These tropical lizards are behaviorally specialized to exploit canopy or sun, and are distributed across marked thermal clines in the AWT. Using phylogenetic analyses, we demonstrate that physiological parameters are either associated with changes in local thermal habitat or to basking behavior, but not both. Cold tolerance, the optimal sprint speed, and performance breadth are primarily influenced by local thermal environment. Specifically, montane lizards are more cool tolerant, have broader performance breadths, and higher optimum sprinting temperatures than their lowland counterparts. Heat tolerance, in contrast, is strongly affected by basking behavior: there are two evolutionary optima, with basking species having considerably higher heat tolerance than shade skinks, with no effect of elevation. These distinct responses among traits indicate the multiple selective pressures and constraints that shape the evolution of thermal performance. We discuss how behavior and physiology interact to shape organisms' vulnerability and potential resilience to climate change. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  4. A Two-Big-Leaf Model for Canopy Temperature, Photosynthesis, and Stomatal Conductance.

    Science.gov (United States)

    Dai, Yongjiu; Dickinson, Robert E.; Wang, Ying-Ping

    2004-06-01

    The energy exchange, evapotranspiration, and carbon exchange by plant canopies depend on leaf stomatal control. The treatment of this control has been required by land components of climate and carbon models. Physiological models can be used to simulate the responses of stomatal conductance to changes in atmospheric and soil environments. Big-leaf models that treat a canopy as a single leaf tend to overestimate fluxes of CO2 and water vapor. Models that differentiate between sunlit and shaded leaves largely overcome these problems.A one-layered, two-big-leaf submodel for photosynthesis, stomatal conductance, leaf temperature, and energy fluxes is presented in this paper. It includes 1) an improved two stream approximation model of radiation transfer of the canopy, with attention to singularities in its solution and with separate integrations of radiation absorption by sunlit and shaded fractions of canopy; 2) a photosynthesis stomatal conductance model for sunlit and shaded leaves separately, and for the simultaneous transfers of CO2 and water vapor into and out of the leaf—leaf physiological properties (i.e., leaf nitrogen concentration, maximum potential electron transport rate, and hence photosynthetic capacity) vary throughout the plant canopy in response to the radiation weight time-mean profile of photosynthetically active radiation (PAR), and the soil water limitation is applied to both maximum rates of leaf carbon uptake by Rubisco and electron transport, and the model scales up from leaf to canopy separately for all sunlit and shaded leaves; 3) a well-built quasi-Newton Raphson method for simultaneous solution of temperatures of the sunlit and shaded leaves.The model was incorporated into the Common Land Model (CLM) and is denoted CLM 2L. It was driven with observational atmospheric forcing from two forest sites [Anglo-Brazilian Amazonian Climate Observation Study (ABRACOS) and Boreal Ecosystem Atmosphere Study (BOREAS)] for 2 yr of simulation. The

  5. Effects of a shade-matching light and background color on reliability in tooth shade selection.

    Science.gov (United States)

    Najafi-Abrandabadi, Siamak; Vahidi, Farhad; Janal, Malvin N

    2018-01-01

    The purpose of this study was to evaluate the effects of a shade-matching light (Rite-Lite-2, AdDent) and different viewing backgrounds on reliability in a test of shade tab matching. Four members of the Prosthodontic faculty matched 10 shade tabs selected for a range of shades against the shade guide. All raters were tested for color blindness and were calibrated prior to the study. Matching took place under four combinations of conditions: with operatory light or the shade-matching light, and using either a pink or a blue background. Reliability was quantified with the kappa statistic, separately for agreement of value, hue, and chroma for each shade tab. In general, raters showed fair to moderate levels of agreement when judging the value of the shade tabs, but could not agree on the hue and chroma of the stimuli. The pink background led to higher levels of agreement than the blue background, and the shade-matching light improved agreement when used in conjunction with the pink but not the blue background. Moderate levels of agreement were found in matching shade tab value. Agreement was generally better when using the pink rather than the blue background, regardless of light source. The use of the shade-matching light tended to amplify the advantage of the pink background.

  6. Reliability and accuracy of four dental shade-matching devices.

    Science.gov (United States)

    Kim-Pusateri, Seungyee; Brewer, Jane D; Davis, Elaine L; Wee, Alvin G

    2009-03-01

    There are several electronic shade-matching instruments available for clinical use, but the reliability and accuracy of these instruments have not been thoroughly investigated. The purpose of this in vitro study was to evaluate the reliability and accuracy of 4 dental shade-matching instruments in a standardized environment. Four shade-matching devices were tested: SpectroShade, ShadeVision, VITA Easyshade, and ShadeScan. Color measurements were made of 3 commercial shade guides (Vitapan Classical, Vitapan 3D-Master, and Chromascop). Shade tabs were placed in the middle of a gingival matrix (Shofu GUMY) with shade tabs of the same nominal shade from additional shade guides placed on both sides. Measurements were made of the central region of the shade tab positioned inside a black box. For the reliability assessment, each shade tab from each of the 3 shade guide types was measured 10 times. For the accuracy assessment, each shade tab from 10 guides of each of the 3 types evaluated was measured once. Differences in reliability and accuracy were evaluated using the Standard Normal z test (2 sided) (alpha=.05) with Bonferroni correction. Reliability of devices was as follows: ShadeVision, 99.0%; SpectroShade, 96.9%; VITA Easyshade, 96.4%; and ShadeScan, 87.4%. A significant difference in reliability was found between ShadeVision and ShadeScan (P=.008). All other comparisons showed similar reliability. Accuracy of devices was as follows: VITA Easyshade, 92.6%; ShadeVision, 84.8%; SpectroShade, 80.2%; and ShadeScan, 66.8%. Significant differences in accuracy were found between all device pairs (Preliability (over 96%), indicating predictable shade values from repeated measurements. However, there was more variability in accuracy among devices (67-93%), and differences in accuracy were seen with most device comparisons.

  7. Shading and vermicompost effect on growth and flavonoid content of Tapak Liman (Elephantopus scaber L.)

    Science.gov (United States)

    Dawiyah, R. Y. A.; Yunus, A.; Samanhudi; Widiyastuti, Y.; Widodo

    2018-03-01

    Tapak Liman (Elephantopus scaber L) is one of Indonesian medicinal plants which is well known as weed. In Thailand, Tapak Limanthis plant is use for traditional medicine due to its flavonoids contains. Flavonoid is compound with red, yellow, purple and blue pigments, used for cancer, aphrodiasiac and anti-radical treatments. One obstacle of Tapak liman cultivation is the effort to increase its flavonoids compound. There is a bridge between flavonoids compound with growth and yield of Tapak Liman. For that, this research aims to find out the effect of shade intensity combined with vermicompost dosage on Tapak Liman growth and yield. This research was conducted in Mei to August 2016 at Medicinal Plantation of BPTO, Tanjungsari Village, Tegal Gede, Karanganyar. Complete Randomized Design compiled with split plot and two factors: shade intensity (0%, 50%, 75%) and vermicompost dosage per plant (0 g, 250 g, 500 g, 750 g) used as the experimental design. The variables observed are leaves number,leaves length, canopy diameter, fresh weight, dry weight, root length, chlorophyl analysis and flavonoid identification. Data were analyzed using ANOVA, any significant treatments followed with Duncan’s Multiple Range Test (DMRT) at α = 10%. Result showed that 75% shade intesity and 750 g of vermicompost has gave highest yield of leaf and total simplicia of Tapak Liman. Shade intensity of 50% with 250 g of and 500 g/plant of vermicompost dosage showed highest flavonoid rendement (Rf 0,5) with highly contrasting spot colors.

  8. The Growth of Agarwood Plants on the Different Canopy Covers Level and Fertilizer in Oil Palm Plantation

    Science.gov (United States)

    Rahayu Prastyaningsih, Sri; Azwin

    2017-12-01

    The development of agar wood plants in oil palm plantation requires the forestry techniques in order to obtain maximum production. In an oil palm stands, the age of plant will affect the height, diameter, population and stands density. The older age of an oil palm stands will affect the canopy cover on the forest floor. Agar wood plants are semi-tolerant growth and oil palm can be used as shade. Unilak has an oil palm plantation area of 10 hectares around the campus with 10 years old and 20 years old. The soil condition at the study is Podsolik Merah Kuning (PMK) which poor nutrient and needs fertilization to increase soil fertility. This study aims to find out the effect of age of oil palm stands and fertilization for optimal growth. The split plot design with 2 main plots of the age of palm tree ( 10 years old and 20 years old) and five kinds of fertilizing sub plot (without fertilizer, 40 gram/plant of NPK, 80 gram/plat of NPK, 120 gram/plant of NPK and 180 gram/plant of NPK were used. The results of this research showed that the age of palm tree (canopy cover) treatment gave non-significant influence on the growing of agar wood until it reaches 4 months of growth. The canopyy cover by 10 years old of oil palm tree produce the best response on height (15 cm) and diameter (0,4 cm) growth of agar woods..Fertilizing treatment di not give any significant influence on the heigh and diameter growth of agarwood plants until reach 3 months. The interaction by 10 years old of palm with fertilizing gave non significant results.

  9. Growth and posture control strategies in Fagus sylvatica and Acer pseudoplatanus saplings in response to canopy disturbance.

    Science.gov (United States)

    Collet, Catherine; Fournier, Mériem; Ningre, François; Hounzandji, Ablo Paul-Igor; Constant, Thiéry

    2011-06-01

    Forest tree saplings that grow in the understorey undergo frequent changes in their light environment to which they must adapt to ensure their survival and growth. Crown architecture, which plays a critical role in light capture and mechanical stability, is a major component of sapling adaptation to canopy disturbance. Shade-adapted saplings typically have plagiotropic stems and branches. After canopy opening, they need to develop more erect shoots in order to exploit the new light conditions. The objective of this study was to test whether changes in sapling stem inclination occur after canopy opening, and to analyse the morphological changes associated with stem reorientation. A 4-year canopy-opening field experiment with naturally regenerated Fagus sylvatica and Acer pseudoplatanus saplings was conducted. The appearance of new stem axes, stem basal diameter and inclination along the stem were recorded every year after canopy opening. Both species showed considerable stem reorientation resulting primarily from uprighting (more erect) shoot movements in Fagus, and from uprighting movements, shoot elongation and formation of relay shoots in Acer. In both species, the magnitude of shoot uprighting movements was primarily related to initial stem inclination. Both the basal part and the apical part of the stem contributed to uprighting movements. Stem movements did not appear to be limited by stem size or by stem growth. Stem uprighting movements in shade-adapted Fagus and Acer saplings following canopy disturbance were considerable and rapid, suggesting that stem reorientation processes play a significant role in the growth strategy of the species.

  10. Stomatal Conductance, Plant Hydraulics, and Multilayer Canopies: A New Paradigm for Earth System Models or Unnecessary Uncertainty

    Science.gov (United States)

    Bonan, G. B.

    2016-12-01

    Soil moisture stress is a key regulator of canopy transpiration, the surface energy budget, and land-atmosphere coupling. Many land surface models used in Earth system models have an ad-hoc parameterization of soil moisture stress that decreases stomatal conductance with soil drying. Parameterization of soil moisture stress from more fundamental principles of plant hydrodynamics is a key research frontier for land surface models. While the biophysical and physiological foundations of such parameterizations are well-known, their best implementation in land surface models is less clear. Land surface models utilize a big-leaf canopy parameterization (or two big-leaves to represent the sunlit and shaded canopy) without vertical gradients in the canopy. However, there are strong biometeorological and physiological gradients in plant canopies. Are these gradients necessary to resolve? Here, I describe a vertically-resolved, multilayer canopy model that calculates leaf temperature and energy fluxes, photosynthesis, stomatal conductance, and leaf water potential at each level in the canopy. In this model, midday leaf water stress manifests in the upper canopy layers, which receive high amounts of solar radiation, have high leaf nitrogen and photosynthetic capacity, and have high stomatal conductance and transpiration rates (in the absence of leaf water stress). Lower levels in the canopy become water stressed in response to longer-term soil moisture drying. I examine the role of vertical gradients in the canopy microclimate (solar radiation, air temperature, vapor pressure, wind speed), structure (leaf area density), and physiology (leaf nitrogen, photosynthetic capacity, stomatal conductance) in determining above canopy fluxes and gradients of transpiration and leaf water potential within the canopy.

  11. Physiological reactions in goat breeds maintained under shade, sun and partially shaded areas

    Directory of Open Access Journals (Sweden)

    Luís Fernando Dias Medeiros

    2015-12-01

    Full Text Available ABSTRACT. Medeiros L.F.D., Rodrigues V.C., Vieira D.H., Souza S.L.G. de, Neto O.C., Figueiredo N. de, Pinto C.F.D., Miranda A.L. & Violento C.B. [Physiological reactions in goat breeds maintained under shade, sun and partially shaded areas.] Reações fisiológicas de cabras em diferentes ambientes e coeficiente de tolerância ao calor em cabritos. Revista Brasileira de Medicina Veterinária, 37(4:286-296, 2015. Departamento de Reprodução e Avaliação Animal, Instituto de Zootecnia, Universidade Federal Rural do Rio de Janeiro, BR 465 Km 7, Seropédica, RJ 23851-970, Brasil. E-mail: diasmedeiros@yahoo.com.br The experiment was carried out to measure the effects of thermal stress on the rectal temperature (RT and respiratory frequency (RF, in animals of Boer and Saanen breeds, under the conditions of hot and humid climate of city of Rio de Janeiro, Baixada Fluminense, South East Region of Brazil; also the heat tolerance coefficient (HTC of Amakiri e Funcho was applied on pure and crossbreeds kids. The goats were divided into three groups, each group consisting of four females from each breed group. Each group was subjected to different surroundings, constituted by three experimental treatment: treatment A, with a sun protected enclosed area; treatment B, a sun exposed area without covering; and treatment C, area with a 50% covered section and a 50% sun exposed area, which permitted free circulation of the goats. A Balanced Latin Square was used. The RT and RF of the goats, in the afternoon periods (l5h00, were higher, than in the morning periods (09h00. The animals kept in the sun presented much higher results, especially in the afternoon periods, than the animals in the other two confinement areas. There were no differences in the RT and RF of the groups maintained in the shade or in partially covered area. There were differences in the RT and RF measurements between the two breeds, in the morning periods and in the afternoon periods

  12. Canopy for VERAView Installation Guide

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ronald W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-09-12

    With the addition of the 3D volume slicer widget, VERAView now relies on Mayavi and its dependents. Enthought's Canopy Python environment provides everything VERAView needs, and pre-built Canopy versions for Windows, Mac OSX, and Linux can be downloaded.

  13. Gainesville's urban forest canopy cover

    Science.gov (United States)

    Francisco Escobedo; Jennifer A. Seitz; Wayne Zipperer

    2009-01-01

    Ecosystem benefits from trees are linked directly to the amount of healthy urban forest canopy cover. Urban forest cover is dynamic and changes over time due to factors such as urban development, windstorms, tree removals, and growth. The amount of a city's canopy cover depends on its land use, climate, and people's preferences. This fact sheet examines how...

  14. Canopy BRF simulation of forest with different crown shape and height in larger scale based on Radiosity method

    Science.gov (United States)

    Song, Jinling; Qu, Yonghua; Wang, Jindi; Wan, Huawei; Liu, Xiaoqing

    2007-06-01

    Radiosity method is based on the computer simulation of 3D real structures of vegetations, such as leaves, branches and stems, which are composed by many facets. Using this method we can simulate the canopy reflectance and its bidirectional distribution of the vegetation canopy in visible and NIR regions. But with vegetations are more complex, more facets to compose them, so large memory and lots of time to calculate view factors are required, which are the choke points of using Radiosity method to calculate canopy BRF of lager scale vegetation scenes. We derived a new method to solve the problem, and the main idea is to abstract vegetation crown shapes and to simplify their structures, which can lessen the number of facets. The facets are given optical properties according to the reflectance, transmission and absorption of the real structure canopy. Based on the above work, we can simulate the canopy BRF of the mix scenes with different species vegetation in the large scale. In this study, taking broadleaf trees as an example, based on their structure characteristics, we abstracted their crowns as ellipsoid shells, and simulated the canopy BRF in visible and NIR regions of the large scale scene with different crown shape and different height ellipsoids. Form this study, we can conclude: LAI, LAD the probability gap, the sunlit and shaded surfaces are more important parameter to simulate the simplified vegetation canopy BRF. And the Radiosity method can apply us canopy BRF data in any conditions for our research.

  15. Effects of shading and covering material application for delaying ...

    African Journals Online (AJOL)

    To delay the harvest of Sultani Cekirdeksiz grape variety and to reduce pre and post-harvest botrytis bunch rot severity, shading and covering material application were tested in 2009 to 2010 growing periods. In this study, grape vines were shaded with shading materials which had three different shading densities (35, 55, ...

  16. Shaded Relief of Minnesota Elevation - Color

    Data.gov (United States)

    Minnesota Department of Natural Resources — This file is a product of a shaded relief process on the 30 meter resolution Digital Elevation Model data (dem30im3). This image was created using a custom AML...

  17. Shaded Relief of Minnesota Elevation - Black & White

    Data.gov (United States)

    Minnesota Department of Natural Resources — This file is a product of a shaded relief process on the 30 meter resolution Digital Elevation Model data (dem30im3). This image was created using a custom AML...

  18. Power producing sun shades; Elproducerende solafskaermninger

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, K.; Soerensen, Henrik; Katic, I.; Schmidt-Petersen, H.; AAroe, D.

    2012-01-15

    Integrating photovoltaics into sun shades takes advantage of the best opportunities to capture and utilize solar energy when the shades are most needed to shield users from solar radiation. The report describes results of a development project for solar shading in the form of broad, horizontal and rotating lamellae with solar cells and an integrated control function that simultaneously is optimized based on energy consumption and thermal and visual indoor climate. The project idea was to meet the needs for effective sun protection in the present office, commercial and public buildings, where glass facades are dominant. The conclusion of the development project is that it rarely would be optimal to integrate solar cells into movable shades. This will normally only be relevant in cases where it is justified by architectural considerations. (LN)

  19. Lake Bathymetric DEM Shaded Relief Image

    Data.gov (United States)

    Minnesota Department of Natural Resources — Geo-referenced, shaded relief image of lake bathymetry classified at 5-foot depth intervals. This dataset has a cell resolution of 5 meters (occasionally 10m) as...

  20. Non-linear effects of drought under shade: reconciling physiological and ecological models in plant communities.

    Science.gov (United States)

    Holmgren, Milena; Gómez-Aparicio, Lorena; Quero, José Luis; Valladares, Fernando

    2012-06-01

    The combined effects of shade and drought on plant performance and the implications for species interactions are highly debated in plant ecology. Empirical evidence for positive and negative effects of shade on the performance of plants under dry conditions supports two contrasting theoretical models about the role of shade under dry conditions: the trade-off and the facilitation hypotheses. We performed a meta-analysis of field and greenhouse studies evaluating the effects of drought at two or more irradiance levels on nine response variables describing plant physiological condition, growth, and survival. We explored differences in plant response across plant functional types, ecosystem types and methodological approaches. The data were best fit using quadratic models indicating a humped-back shape response to drought along an irradiance gradient for survival, whole plant biomass, maximum photosynthetic capacity, stomatal conductance and maximal photochemical efficiency. Drought effects were ameliorated at intermediate irradiance, becoming more severe at higher or lower light levels. This general pattern was maintained when controlling for potential variations in the strength of the drought treatment among light levels. Our quantitative meta-analysis indicates that dense shade ameliorates drought especially among drought-intolerant and shade-tolerant species. Wet tropical species showed larger negative effects of drought with increasing irradiance than semiarid and cold temperate species. Non-linear responses to irradiance were stronger under field conditions than under controlled greenhouse conditions. Non-linear responses to drought along the irradiance gradient reconciliate opposing views in plant ecology, indicating that facilitation is more likely within certain range of environmental conditions, fading under deep shade, especially for drought-tolerant species.

  1. Shade variance in ceramic restoration and shade tab: An in vitro study

    Directory of Open Access Journals (Sweden)

    Pannaikadu Somasundaram Prabu

    2012-01-01

    Full Text Available Background: In clinical practice aesthetics for any restoration needs to consider the parameters of surface form, translucency and colour.To achieve ideal aesthetics the colour replication process for dental porcelain is the most important step which comprises of a shade selection phase followed by shade duplication. Materials and Methods: The ceramic brands Vita VMK95 (classic and Ivoclar classic V were used for comparison with Vita classic shade tab guide shades A2 and B2. The samples were made of specific shape, size, and were of the recommended dimensions from investing self-cure acrylic strips to casted NiCr specimens Objective. The objective of this study was to quantify the results in CIE AE units system for the colour differences between the Vita shade guide colours and two commercial porcelains for metal ceramic crowns. Results: The results indicated that the porcelains do not match the shade guides to which they are compared and shade variations exist between different lots of porcelain from the same and different manufacturer. Conclusion: Problems identified that porcelains do not match the shade guides to which they are compared and shade variations exist between different lots of porcelain from the same and different manufacturer

  2. Canopy gaps affect long-term patterns of tree growth and mortality in mature and old-growth forests in the Pacific Northwest

    Science.gov (United States)

    Andrew N. Gray; Thomas A. Spies; Robert J. Pabst

    2012-01-01

    Canopy gaps created by tree mortality can affect the speed and trajectory of vegetation growth. Species’ population dynamics, and spatial heterogeneity in mature forests. Most studies focus on plant development within gaps, yet gaps also affect the mortality and growth of surrounding trees, which influence shading and root encroachment into gaps and determine whether,...

  3. A photosynthesis-based two-leaf canopy stomatal conductance model for meteorology and air quality modeling with WRF/CMAQ PX LSM

    Science.gov (United States)

    A coupled photosynthesis-stomatal conductance model with single-layer sunlit and shaded leaf canopy scaling is implemented and evaluated in a diagnostic box model with the Pleim-Xiu land surface model (PX LSM) and ozone deposition model components taken directly from the meteorol...

  4. Ethnicity and perception of dental shade esthetics.

    Science.gov (United States)

    Niaz, Muhammad Omar; Naseem, Mustafa; Elcock, Claire

    2015-01-01

    To determine whether or not people from different ethnic backgrounds have different attitudes towards dental esthetics and chose different dental appearances in terms of tooth shade, and to determine whether the dental professional's choice and the individual's own choice have any relationship with what the individual ideally perceives as esthetically pleasing. For this cross-sectional analytical study, 120 volunteer students from the University of Sheffield (excepting dental students) from various ethnic backgrounds, of different ages, of both genders, and with varying degree/educational levels were recruited from the campus. The volunteers were asked to complete a questionnaire containing 9 adapted attitudinal statements regarding positive or negative dental esthetic perceptions in terms of tooth shade, with responses on a 5-point Likert scale from "Entirely agree" to "Entirely disagree". Scores for all attitudinal statements were summed up to give an attitudinal score. The participants' ideal, perceived, and actual (self-assessed and investigatorassessed) tooth shade was also determined using a shade guide and a facial mirror. No association between ethnicity and attitudinal score was found. However, statistically significant associations were found between the participants' degree/educational level (P=0.004, 95% Confidence Interval (CI)=-4.18 to -0.82) and their ideal tooth shade value (P=0.038, 95% CI=-3.53 to -0.11). There were strong correlations between self-assessed and professionally assessed tooth shade value in all ethnic groups, with Spearman's rank correlation coefficient (rho) being ρ>0.6. Regarding ideally desired and perceived tooth shade value, weak correlations were found in all ethnic groups (Spearman's rho being ρethnicity and attitude towards dental esthetics with regard to tooth shade, both ethnicity and dental esthetics are very diverse terms with multiple dimensions, each of which needs further investigation with regard to their mutual

  5. Tree age dependence and within-canopy variation of leaf gas exchange and antioxidative defence in Fagus sylvatica under experimental free-air ozone exposure

    International Nuclear Information System (INIS)

    Herbinger, K.; Then, Ch.; Loew, M.; Haberer, K.; Alexous, M.; Koch, N.; Remele, K.; Heerdt, C.; Grill, D.; Rennenberg, H.; Haeberle, K.-H.; Matyssek, R.; Tausz, M.; Wieser, G.

    2005-01-01

    We characterized leaf gas exchange and antioxidative defence of two-year-old seedlings and 60-year-old trees of Fagus sylvatica exposed to ambient (1xO 3 ) or two-fold ambient (2xO 3 ) O 3 concentrations (maximum of 150 ppb) in a free-air canopy exposure system throughout the growing season. Decline in photosynthesis from sun-exposed to shaded conditions was more pronounced in adult than juvenile trees. Seedling leaves and leaves in the sun-exposed canopy had higher stomatal conductance and higher internal CO 2 concentrations relative to leaves of adult trees and leaves in shaded conditions. There was a weak overall depression of photosynthesis in the 2xO 3 variants across age classes and canopy positions. Pigment and tocopherol concentrations of leaves were significantly affected by canopy position and tree age, whereas differences between 1xO 3 and 2xO 3 regimes were not observed. Glutathione concentrations were significantly increased under 2xO 3 across both age classes and canopy levels. Seedlings differed from adult trees in relevant physiological and biochemical traits in ozone response. The water-soluble antioxidative systems responded most sensitively to 2xO 3 without regard of tree age or canopy position. - Ozone effects on leaf gas exchange and antioxidative systems of beech across tree age and canopy level were investigated in a free air exposure system

  6. Tree age dependence and within-canopy variation of leaf gas exchange and antioxidative defence in Fagus sylvatica under experimental free-air ozone exposure

    Energy Technology Data Exchange (ETDEWEB)

    Herbinger, K. [Institut fuer Pflanzenwissenschaften, Universitaet Graz, Schubertstrasse 51, A-8010 Graz (Austria)]. E-mail: karin.herbinger@uni-graz.at; Then, Ch. [Bundesamt und Forschungszentrum fuer Wald, Abteilung Forstpflanzenphysiologie, Rennweg 1, A-6020 Innsbruck (Austria)]|[Lehrstuhl fuer Oekophysiologie der Pflanzen, Technische Universitaet Muenchen, Life Sciences Center Weihenstephan, Am Hochanger 13, D-85354 Freising (Germany); Loew, M.; Koch, N. [Lehrstuhl fuer Oekophysiologie der Pflanzen, Technische Universitaet Muenchen, Life Sciences Center Weihenstephan, Am Hochanger 13, D-85354 Freising (Germany); Haberer, K.; Alexous, M. [Institut fuer Forstbotanik und Baumphysiologie, Universitaet Freiburg, Georges-Koehler-Allee 053/054, D-79085 Freiburg (Germany); Remele, K. [Institut fuer Pflanzenwissenschaften, Universitaet Graz, Schubertstrasse 51, A-8010 Graz (Austria); Heerdt, C. [Lehrstuhl fuer Bioklimatologie und Immissionsforschung, Technische Universitaet Muenchen, Am Hochanger 13, D-85354 Freising (Germany); Grill, D. [Institut fuer Pflanzenwissenschaften, Universitaet Graz, Schubertstrasse 51, A-8010 Graz (Austria); Rennenberg, H. [Institut fuer Forstbotanik und Baumphysiologie, Universitaet Freiburg, Georges-Koehler-Allee 053/054, D-79085 Freiburg (Germany); Haeberle, K.-H.; Matyssek, R. [Lehrstuhl fuer Oekophysiologie der Pflanzen, Technische Universitaet Muenchen, Life Sciences Center Weihenstephan, Am Hochanger 13, D-85354 Freising (Germany); Tausz, M. [Institut fuer Pflanzenwissenschaften, Universitaet Graz, Schubertstrasse 51, A-8010 Graz (Austria)]|[[School of Forest and Ecosystem Science, University of Melbourne, Water Street, Creswick, Vic. 3363 (Australia); Wieser, G. [Bundesamt und Forschungszentrum fuer Wald, Abteilung Forstpflanzenphysiologie, Rennweg 1, A-6020 Innsbruck (Austria)

    2005-10-15

    We characterized leaf gas exchange and antioxidative defence of two-year-old seedlings and 60-year-old trees of Fagus sylvatica exposed to ambient (1xO{sub 3}) or two-fold ambient (2xO{sub 3}) O{sub 3} concentrations (maximum of 150 ppb) in a free-air canopy exposure system throughout the growing season. Decline in photosynthesis from sun-exposed to shaded conditions was more pronounced in adult than juvenile trees. Seedling leaves and leaves in the sun-exposed canopy had higher stomatal conductance and higher internal CO{sub 2} concentrations relative to leaves of adult trees and leaves in shaded conditions. There was a weak overall depression of photosynthesis in the 2xO{sub 3} variants across age classes and canopy positions. Pigment and tocopherol concentrations of leaves were significantly affected by canopy position and tree age, whereas differences between 1xO{sub 3} and 2xO{sub 3} regimes were not observed. Glutathione concentrations were significantly increased under 2xO{sub 3} across both age classes and canopy levels. Seedlings differed from adult trees in relevant physiological and biochemical traits in ozone response. The water-soluble antioxidative systems responded most sensitively to 2xO{sub 3} without regard of tree age or canopy position. - Ozone effects on leaf gas exchange and antioxidative systems of beech across tree age and canopy level were investigated in a free air exposure system.

  7. Utilizing In Situ Directional Hyperspectral Measurements to Validate Bio-Indicator Simulations for a Corn Crop Canopy

    Science.gov (United States)

    Cheng, Yen-Ben; Middleton, Elizabeth M.; Huemmrich, Karl F.; Zhang, Qingyuan; Campbell, Petya K. E.; Corp, Lawrence A.; Russ, Andrew L.; Kustas, William P.

    2010-01-01

    Two radiative transfer canopy models, SAIL and the two-layer Markov-Chain Canopy Reflectance Model (MCRM), were coupled with in situ leaf optical properties to simulate canopy-level spectral band ratio vegetation indices with the focus on the photochemical reflectance index in a cornfield. In situ hyperspectral measurements were made at both leaf and canopy levels. Leaf optical properties were obtained from both sunlit and shaded leaves. Canopy reflectance was acquired for eight different relative azimuth angles (psi) at three different view zenith angles (Theta (sub v)), and later used to validate model outputs. Field observations of photochemical reflectance index (PRI) for sunlit leaves exhibited lower values than shaded leaves, indicating higher light stress. Canopy PRI expressed obvious sensitivity to viewing geometry, as a function of both Theta (sub v) and psi . Overall, simulations from MCRM exhibited better agreements with in situ values than SAIL. When using only sunlit leaves as input, the MCRM-simulated PRI values showed satisfactory correlation and RMSE, as compared to in situ values. However, the performance of the MCRM model was significantly improved after defining a lower canopy layer comprised of shaded leaves beneath the upper sunlit leaf layer. Four other widely used band ratio vegetation indices were also studied and compared with the PRI results. MCRM simulations were able to generate satisfactory simulations for these other four indices when using only sunlit leaves as input; but unlike PRI, adding shaded leaves did not improve the performance of MCRM. These results support the hypothesis that the PRI is sensitive to physiological dynamics while the others detect static factors related to canopy structure. Sensitivity analysis was performed on MCRM in order to better understand the effects of structure related parameters on the PRI simulations. Leaf area index (LAI) showed the most significant impact on MCRM-simulated PRI among the parameters

  8. Plant photomorphogenesis and canopy growth

    Science.gov (United States)

    Ballare, Carlos L.; Scopel, Ana L.

    1994-01-01

    An important motivation for studying photomorphogenesis is to understand the relationships among plant photophysiology in canopies, canopy productivity, and agronomic yield. This understanding is essential to optimize lighting systems used for plant farming in controlled environments (CE) and for the design of genetically engineered crop strains with altered photoresponses. This article provides an overview of some basic principles of plant photomorphogenesis in canopies and discusses their implications for (1) scaling up information on plant photophysiology from individual plants in CE to whole canopies in the field, and (2) designing lighting conditions to increase plant productivity in CE used for agronomic purposes (e.g. space farming in CE Life Support Systems). We concentrate on the visible (lambda between 400 and 700 nm) and far-infrared (FR; lambda greater than 700 nm) spectral regions, since the ultraviolet (UV; 280 to 400 nm) is covered by other authors in this volume.

  9. Plant photomorphogenesis and canopy growth

    Energy Technology Data Exchange (ETDEWEB)

    Ballare, C.L.; Scopel, A.L. [Universidad de Buenos Aires (Argentina)

    1994-12-31

    An important motivation for studying photomorphogenesis is to understand the relationships among plant photophysiology in canopies, canopy productivity, and agronomic yield. This understanding is essential to optimize lighting systems used for plant farming in controlled environments (CE) and for the design of genetically engineered crop strains with altered photoresponses. This article provides an overview of some basic principles of plant photomorphogenesis in canopies and discusses their implications for (1) scaling up information on plant photophysiology from individual plants in CE to whole canopies in the field, and (2), designing lighting conditions to increase plant productivity in CE used for agronomic purposes [e.g. space farming in CE Life-Support-Systems]. We concentrate on the visible ({lambda} between 400 and 700 nm) and far red (FR; {lambda} > 700 nm) spectral regions, since the ultraviolet (UV; 280 to 400 nm) is covered by other authors in this volume.

  10. Canopy position affects the relationships between leaf respiration and associated traits in a tropical rainforest in Far North Queensland.

    Science.gov (United States)

    Weerasinghe, Lasantha K; Creek, Danielle; Crous, Kristine Y; Xiang, Shuang; Liddell, Michael J; Turnbull, Matthew H; Atkin, Owen K

    2014-06-01

    We explored the impact of canopy position on leaf respiration (R) and associated traits in tree and shrub species growing in a lowland tropical rainforest in Far North Queensland, Australia. The range of traits quantified included: leaf R in darkness (RD) and in the light (RL; estimated using the Kok method); the temperature (T)-sensitivity of RD; light-saturated photosynthesis (Asat); leaf dry mass per unit area (LMA); and concentrations of leaf nitrogen (N), phosphorus (P), soluble sugars and starch. We found that LMA, and area-based N, P, sugars and starch concentrations were all higher in sun-exposed/upper canopy leaves, compared with their shaded/lower canopy and deep-shade/understory counterparts; similarly, area-based rates of RD, RL and Asat (at 28 °C) were all higher in the upper canopy leaves, indicating higher metabolic capacity in the upper canopy. The extent to which light inhibited R did not differ significantly between upper and lower canopy leaves, with the overall average inhibition being 32% across both canopy levels. Log-log RD-Asat relationships differed between upper and lower canopy leaves, with upper canopy leaves exhibiting higher rates of RD for a given Asat (both on an area and mass basis), as well as higher mass-based rates of RD for a given [N] and [P]. Over the 25-45 °C range, the T-sensitivity of RD was similar in upper and lower canopy leaves, with both canopy positions exhibiting Q10 values near 2.0 (i.e., doubling for every 10 °C rise in T) and Tmax values near 60 °C (i.e., T where RD reached maximal values). Thus, while rates of RD at 28 °C decreased with increasing depth in the canopy, the T-dependence of RD remained constant; these findings have important implications for vegetation-climate models that seek to predict carbon fluxes between tropical lowland rainforests and the atmosphere. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  11. CANOPY ARCHITECTURE, LIGHT EXTINCTION AND SELF-SHADING OF A PRAIRIE GRASS, ANDROPOGON GERARDII. (R825796)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  12. Plasticity to canopy shade in a monocarpic herb: within- and between-generation effects.

    Science.gov (United States)

    Galloway, Laura F; Etterson, Julie R

    2009-06-01

    Plants exhibit plasticity in response to their current environment and, in some cases, to that of the previous generation (i.e. maternal effects). However, few studies have evaluated both within- and between-generation plasticities and the extent to which they interact to influence fitness, especially in natural environments. The plasticity of adult traits to two generations of natural differences in light was determined for Campanulastrum americanum, a forest-edge herb that expresses annual and biennial life histories. Plasticity was found to an individual's light environment (within generation) and the maternal light environment (between generations). Responses to ambient light for size traits and timing of flowering were probably passive, whereas apparently adaptive responses were found for light acquisition traits. Maternal light influenced the expression of most adult traits but had the strongest effect when plants were germinated in natural environments. The transgenerational effects of light were consistent with adaptive plasticity for several traits. Plastic within-generation changes in flowering time may also result in adaptive between-generation effects by altering the offspring life history schedule. Finally, the results underscore the importance of conducting studies of within- and between-generation plasticity in natural populations, where the environmental context is relevant to that in which the traits evolved.

  13. Recruitment and attrition of associated plants under a shading crop canopy: Model selection and calibration

    NARCIS (Netherlands)

    Stilma, E.S.C.; Keesman, K.J.; Werf, van der W.

    2009-01-01

    Associated plant and animal diversity provides ecosystem services within crop production systems. The importance of the maintenance or restoration of diversity is therefore increasingly acknowledged. Here we study the population dynamics of associated annual plants (`weeds¿) during the growth of a

  14. Shade guide optimization--a novel shade arrangement principle for both ceramic and composite shade guides when identifying composite test objects.

    Science.gov (United States)

    Østervemb, Niels; Jørgensen, Jette Nedergaard; Hørsted-Bindslev, Preben

    2011-02-01

    The most widely used shade guide for composite materials is made of ceramic and arranged according to a non-proven method. There is a need for a composite shade guide using a scientifically based arrangement principle. To compare the shade tab arrangement of the Vitapan Classical shade guide and an individually made composite shade guide using both the originally proposed arrangement principle and arranged according to ΔE2000 values with hue group division. An individual composite shade guide made from Filtek Supreme XT body colors was compared to the Vitapan Classical shade guide. Twenty-five students matched color samples made from Filtek Supreme XT body colors using the two shade guides arranged after the two proposed principles--four shade guides in total. Age, sequence, gender, time, and number of correct matches were recorded. The proposed visually optimal composite shade guide was both fastest and had the highest number of correct matches. Gender was significantly associated with time used for color sampling but not regarding the number of correct shade matches. A composite shade guide is superior compared to the ceramic Vitapan Classical guide when using composite test objects. A rearrangement of the shade guide according to hue, subdivided according to ΔE2000, significantly reduces the time needed to take a color sample and increases the number of correct shade matches. Total color difference in relation to the lightest tab with hue group division is recommended as a possible and universally applicable mode of tab arrangement in dental color standards. Moreover, a shade guide made of the composite materials itself is to be preferred as both a faster and more accurate method of determining color. © 2011, COPYRIGHT THE AUTHORS. JOURNAL COMPILATION © 2011, WILEY PERIODICALS, INC.

  15. Canopy accession strategies and climate-growth relationships in Acer Rubrum.

    Science.gov (United States)

    Justin L. Hart; Megan L. Buchanan; Scott J. Torreano

    2012-01-01

    A pervasive pattern of forest composition change is occurring throughout the Central Hardwood Forest of the eastern US. Acer rubrum has invaded the understory of Quercus stands across a variety of site types. The proliferation of A. rubrum, and that of other shade-tolerant mesophytes, inhibits the regeneration of Quercus. Without alterations in disturbance or climate...

  16. Effects of diffuse radiation on canopy gas exchange processes in a forest ecosystem

    Science.gov (United States)

    Knohl, Alexander; Baldocchi, Dennis D.

    2008-06-01

    Forest ecosystems across the globe show an increase in ecosystem carbon uptake efficiency under conditions with high fraction of diffuse radiation. Here, we combine eddy covariance flux measurements at a deciduous temperate forest in central Germany with canopy-scale modeling using the biophysical multilayer model CANVEG to investigate the impact of diffuse radiation on various canopy gas exchange processes and to elucidate the underlying mechanisms. Increasing diffuse radiation enhances canopy photosynthesis by redistributing the solar radiation load from light saturated sunlit leaves to nonsaturated shade leaves. Interactions with atmospheric vapor pressure deficit and reduced leaf respiration are only of minor importance to canopy photosynthesis. The response strength of carbon uptake to diffuse radiation depends on canopy characteristics such as leaf area index and leaf optical properties. Our model computations shows that both canopy photosynthesis and transpiration increase initially with diffuse fraction, but decrease after an optimum at a diffuse fraction of 0.45 due to reduction in global radiation. The initial increase in canopy photosynthesis exceeds the increase in transpiration, leading to a rise in water-use-efficiency. Our model predicts an increase in carbon isotope discrimination with water-use-efficiency resulting from differences in the leaf-to-air vapor pressure gradient and atmospheric vapor pressure deficit. This finding is in contrast to those predicted with simple big-leaf models that do not explicitly calculate leaf energy balance. At an annual scale, we estimate a decrease in annual carbon uptake for a potential increase in diffuse fraction, since diffuse fraction was beyond the optimum for 61% of the data.

  17. Abiotic alterations caused by forest fragmentation affect tree regeneration: a shade and drought tolerance gradient in the remnants of Coastal Maulino Forest Alteraciones abióticas causadas por la fragmentación del bosque afectan la regeneración arbórea: un gradiente de tolerancia a la sombra y la sequía en los remanentes del Bosque Maulino Costero

    Directory of Open Access Journals (Sweden)

    PABLO C GUERRERO

    2009-01-01

    Full Text Available Plant regeneration is strongly determined by light and soil moisture differences between habitáis; both variables are modified by large-scale forest fragmentation. Several studies have indicated this alteration as the mechanism involved in tropical forest community change. The effects of fragmentation may be much more severe in Mediterranean and deciduous forests, because plant species in these forests show a stress tolerance tradeoff between shade and drought. Our study was performed in the deciduous fragmented Coastal Maulino Forest: Reserva Nacional Los Queules (RNLQ and surrounding small fragments. We hypothesised that Aristotelia chilensis (shade intolerant but drought tolerant should increase its regeneration in small patches as a consequence of the change in habitat suitability (i.e. luminous and drier, while Cryptocarya alba (shade tolerant but drought intolerant should have less regeneration in small fragments. We also expected that Nothofagus glauca and N. obliqua, which have shade and drought tolerances intermedíate between A. chilensis and C. alba, should respond less to forest fragmentation. We used two estimations of plant regeneration: (i seedling and sapling densities via field observations and (ii seed germination and seedling establishment via a field-based experiment. Natural regeneration patterns of C. alba indicated a depressed regeneration within small forest fragments compared to RNLQ, although experimental germination, establishment and recruitment proportions did not vary between habitáis. In contrast, A. chilensis regeneration was favored by forest fragmentation, with increased seedling and sapling densities and germination in small forest fragments. Both N. glauca and N. obliqua were less affected by forest fragmentation in their natural and experimental regeneration. This study highlights the relevance of studying changes in abiotic factors as a consequence of human activities, and considering safe sites (defined

  18. Minimisation of Power loss from partially shaded solar cell arrays

    Energy Technology Data Exchange (ETDEWEB)

    Maine, Tony; Bell, John [Queensland University of Technology, Brisbane (Australia). Built Environment Engineering; Martin, Stewart [University of South Australia, Mawson Lakes Campus, SA (Australia). School of Electrical and Information Engineering

    2008-07-01

    In conventional wiring schemes the output from a partially shaded solar cell array drops rapidly to that of the fully shaded array even when only a small fraction is shaded. In this paper circuit simulation has been used to show that by dynamically reconfiguring the array, the power losses due to shading can be significantly reduced. Reconfiguration is achieved by using switching microcircuits with on-chip photo detectors to determine which parts of the array are in shade. The currents from the shaded and unshaded sections of the array are separated and then connected in parallel to a maximum power point tracker. It is shown that by using this reconfiguration that the power output from a partially shaded array can be increased by at least 100% compared with that from a conventional series connected array over a range of shading conditions. (orig.)

  19. USGS Hill Shade Base Map Service from The National Map

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — USGS Hill Shade (or Shaded Relief) is a tile cache base map created from the National Elevation Dataset (NED), a seamless dataset of best available raster elevation...

  20. Experimental and Numerical Analysis of Modelling of Solar Shading

    DEFF Research Database (Denmark)

    Winther, Frederik Vildbrad; Liu, Mingzhe; Heiselberg, Per

    2017-01-01

    The use of solar shading in future low energy office buildings is essential for minimizing energy consumption for building services, while maintaining thermal conditions. Implementing solar shading technologies in energy calculations and thermal building simulation programs is essential in order...... to demonstrate the effect of adaptive solar shading. In order to document the benefits of the shading technology, the description of the shading device in the thermal building simulation software must be described at a reasonably accurate level, related to the specific solar shading device. This research...... presents different approaches for modeling solar shading devices, demonstrating the level of accuracy in relation to measurement conducted in a full-scale façade test facility at Aalborg University. The research bridges the gap between increased complexity of solar shading technologies and the use...

  1. Solar shading control strategy for office buildings in cold climate

    DEFF Research Database (Denmark)

    Røseth Karlsen, Line; Heiselberg, Per Kvols; Bryn, Ida

    2016-01-01

    Highlights •Solar shading control strategy for office buildings in cold climate is developed. •Satisfying energy and indoor environmental performance is confirmed. •Importance of integrated evaluations when selecting shading strategy is illustrated.......Highlights •Solar shading control strategy for office buildings in cold climate is developed. •Satisfying energy and indoor environmental performance is confirmed. •Importance of integrated evaluations when selecting shading strategy is illustrated....

  2. Plants' responses to drought and shade environments

    African Journals Online (AJOL)

    전병기

    Among them, drought is widely known as the main factor that limits plants' growth, productivity and development (Reddy et al., 2004; Shao et al., 2008; Li et al., 2009). Recently, drought occured frequently all over the globe due to climate changes (Khaine and Woo, 2015). Light and shade are very important environements ...

  3. Net herbage accumulation rate and crude protein content of Urochloa brizantha cultivars under shade intensities

    Directory of Open Access Journals (Sweden)

    Paulo Roberto de Lima Meirelles

    2013-12-01

    Full Text Available The use of silvopastoral systems is a sustainable alternative for animal production in various regions of the Brazil. However to obtain satisfactory results in these systems, the selection of forage species that grows well in the shade should be done. The tolerance of plants to light restriction and the correctly choice of species, considering good nutritional values for these conditions has great importance. The study of artificial shading for forage production helps the clarification of issues related to the behavior of plants under reduced light prior to use in integrations with forests. The aim of the study was to evaluate the net herbage accumulation rate of forage (HAR and crude protein (CP of Urochloa brizantha cultivars (Marandu and Piatã under natural light and shading of 30 and 60%. The experiment was conducted at FMVZ - UNESP, Botucatu. The experimental design was a randomized block in factorial arrangement 3 x 2 (three shading levels: 0, 30 and 60%, two cultivars: Marandu and Piatã with three replications and repeated measures (3 cuts. Sample collection occurred when the cultivars reached 35 cm in height. The treatments with shading showed lower cutting intervals as compared to those subjected to full sunlight, because they have reached in a shorter time to time as determined cut-off criterion (mean of 37, 45 and 61 days for reduction of 60%, reduction of 30% and full sun. Significant effects (P<0.05 interaction cultivar x shade x cut on the net herbage accumulation rate (HAR. Most HAR (P<0.05 was observed for cv. Marandu 60% reduction in lightness (127 kg/ha/day due to increased production of stem during the first growing cycle. The lower HAR also occurred to Marandu, but under natural light in the third cut (34 kg/ha/day due to adverse weather conditions during the growth interval. The shadow effect and the cutting (P<0.05 affected CP. The percentage of CP on cultivars showed the highest values (average value of 9.27% in 60

  4. Effects of street tree shade on asphalt concrete pavement performance

    Science.gov (United States)

    E.G. McPherson; J. Muchnick

    2005-01-01

    Forty-eight street segments were paired into 24 high-and low-shade pairs in Modesto, California, U.S. Field data were collected to calculate a Pavement Condition Index (PCI) and Tree Shade Index (TSI) for each segment. Statistical analyses found that greater PCI was associated with greater TSI, indicating that tree shade was partially responsible for reduced pavement...

  5. Influence of Shading on Cooling Energy Demand

    Science.gov (United States)

    Rabczak, Sławomir; Bukowska, Maria; Proszak-Miąsik, Danuta; Nowak, Krzysztof

    2017-10-01

    The article presents an analysis of the building cooling load taking into account the variability of the factors affecting the size of the heat gains. In order to minimize the demand for cooling, the effect of shading elements installed on the outside on the windows and its effect on size of the cooling capacity of air conditioning system for the building has been estimated. Multivariate building cooling load calculations to determine the size of the reduction in cooling demand has derived. Determination of heat gain from the sun is laborious, but gives a result which reflects the influence of the surface transparent partitions, devices used as sunscreen and its location on the building envelope in relation to the world, as well as to the internal heat gains has great attention in obtained calculation. In this study, included in the balance sheet of solar heat gains are defined in three different shading of windows. Calculating the total demand cooling is made for variants assuming 0% shading baffles transparent, 50% shading baffles transparent external shutters at an angle of 45 °, 100% shading baffles transparent hours 12 from the N and E and from 12 from the S and W of the outer slat blinds. The calculation of the average hourly cooling load was taken into account the option assuming the hypothetical possibility of default by up to 10% of the time assumed the cooling season temperatures in the rooms. To reduce the consumption of electricity energy in the cooling system of the smallest variant identified the need for the power supply for the operation of the cooling system. Also assessed the financial benefits of the temporary default of comfort.

  6. Temperature profile in apricot tree canopies under the soil and climate conditions of the Romanian Black Sea Coast

    Science.gov (United States)

    Paltineanu, Cristian; Septar, Leinar; Chitu, Emil

    2016-03-01

    The paper describes the temperature profiles determined by thermal imagery in apricot tree canopies under the semi-arid conditions of the Black Sea Coast in a chernozem of Dobrogea Region, Romania. The study analyzes the thermal vertical profile of apricot orchards for three representative cultivars during summertime. Measurements were done when the soil water content (SWC) was at field capacity (FC) within the rooting depth, after intense sprinkler irrigation applications. Canopy temperature was measured during clear sky days at three heights for both sides of the apricot trees, sunlit (south), and shaded (north). For the SWC studied, i.e., FC, canopy height did not induce a significant difference between the temperature of apricot tree leaves (Tc) and the ambient air temperature (Ta) within the entire vertical tree profile, and temperature measurements by thermal imagery can therefore be taken at any height on the tree crown leaves. Differences between sunlit and shaded sides of the canopy were significant. Because of these differences for Tc-Ta among the apricot tree cultivars studied, lower base lines (LBLs) should be determined for each cultivar separately. The use of thermal imagery technique under the conditions of semi-arid coastal areas with low range of vapor pressure deficit could be useful in irrigation scheduling of apricot trees. The paper discusses the implications of the data obtained in the experiment under the conditions of the coastal area of the Black Sea, Romania, and neighboring countries with similar climate, such as Bulgaria and Turkey.

  7. Young Women's Perceptions of the Relationship in Fifty Shades of Grey.

    Science.gov (United States)

    Bonomi, Amy E; Nichols, Emily M; Carotta, Christin L; Kiuchi, Yuya; Perry, Samantha

    2016-02-01

    Millions of women are interacting with Fifty Shades of Grey-a best-selling novel and film. Yet, to date, no social science study has been undertaken to examine women's perceptions of the Fifty Shades relationship narrative in its film adaptation-what they deem appealing, what they deem unappealing, and what they would welcome or resist in their own relationship. In the present study, we used focus groups to examine women's perceptions of the relationship patterns in the Fifty Shades of Grey film. Focus groups were conducted with 35 young adult women (randomly sampled from the registrar's office of a large Midwestern university) immediately after watching the Fifty Shades film with the study team at a local theater within two days of the film's release. Seven semistructured questions concentrating on reactions to the relationship patterns between Christian Grey and Anastasia Steele depicted in the Fifty Shades film were asked, including general reactions, appealing and unappealing characteristics, romantic and dangerous elements, and aspects that participants would tolerate (or not tolerate) in their own relationships. While participants assessed parts of the relationship between Christian and Anastasia as exciting and romantic, they consistently indicated an unappealing lack of health in the relationship. Participants expressed grave concerns over Christian's stalking, controlling, manipulative, and emotionally abusive behavior, anger in sexual interactions, and neglect of Anastasia's needs. At the same time, they sympathized with and rationalized Christian's behaviors as a function of his personality, needs, and abilities. A small contingent implicated Anastasia in the unhealthy relationship process, whereas a broader majority of participants highlighted the challenges with trying to "speak up" in an unhealthy relationship like Christian and Anastasia's. When asked where participants would draw the line in their own relationship, participants indicated they would

  8. Initial Development of Four Forest Species in Different Shading Conditions

    Directory of Open Access Journals (Sweden)

    C. C. Silva

    2013-07-01

    Full Text Available Abstract: Evaluated the initial development through destructive and non-destructive sampling, forest species Adenanthera pavonina, Cassia fistula, Parkia pendula and Hymenolobium petraeum, propagated by seeds at different levels of shading screens black poliefinas (0, 50 and 65% , in the region of Sinop, MT. There were no significant interactions between time and level of shading to any variable. Changes in fresh and dry weight at all levels of shading occurred from 30 DAT. The highest rates of growth were observed in 50% shading to A. pavonina, P. pendula and H. petraeum and 65% shading for C. fistula.Keywords: seedling, growth, physiology, climatic conditions.

  9. Canopy temperature depression at grain filling correlates to winter wheat yield in the U.S. southern high plains

    Science.gov (United States)

    Wheat breeding has improved drought tolerance over the years. However, our knowledge on drought tolerance in relation to the canopy temperature (CT) and grain yield is limited. A three-season wheat field study ending 2012, 2015, and 2016 was conducted at Bushland, Texas to investigate the relationsh...

  10. Consistency in color parameters of a commonly used shade guide.

    Science.gov (United States)

    Tashkandi, Esam

    2010-01-01

    The use of shade guides to assess the color of natural teeth subjectively remains one of the most common means for dental shade assessment. Any variation in the color parameters of the different shade guides may lead to significant clinical implications. Particularly, since the communication between the clinic and the dental laboratory is based on using the shade guide designation. The purpose of this study was to investigate the consistency of the L∗a∗b∗ color parameters of a sample of a commonly used shade guide. The color parameters of a total of 100 VITAPAN Classical Vacuum shade guide (VITA Zahnfabrik, Bad Säckingen, Germany(were measured using a X-Rite ColorEye 7000A Spectrophotometer (Grand Rapids, Michigan, USA). Each shade guide consists of 16 tabs with different designations. Each shade tab was measured five times and the average values were calculated. The ΔE between the average L∗a∗b∗ value for each shade tab and the average of the 100 shade tabs of the same designation was calculated. Using the Student t-test analysis, no significant differences were found among the measured sample. There is a high consistency level in terms of color parameters of the measured VITAPAN Classical Vacuum shade guide sample tested.

  11. Compliance of secondary production and eco-exergy as indicators of benthic macroinvertebrates assemblages' response to canopy cover conditions in Neotropical headwater streams.

    Science.gov (United States)

    Linares, Marden Seabra; Callisto, Marcos; Marques, João Carlos

    2018-02-01

    Riparian vegetation cover influences benthic assemblages structure and functioning in headwater streams, as it regulates light availability and autochthonous primary production in these ecosystems.Secondary production, diversity, and exergy-based indicators were applied in capturing how riparian cover influences the structure and functioning of benthic macroinvertebrate assemblages in tropical headwater streams. Four hypotheses were tested: (1) open canopy will determine the occurrence of higher diversity in benthic macroinvertebrate assemblages; (2) streams with open canopy will exhibit more complex benthic macroinvertebrate communities (in terms of information embedded in the organisms' biomass); (3) in streams with open canopy benthic macroinvertebrate assemblages will be more efficient in using the available resources to build structure, which will be reflected by higher eco-exergy values; (4) benthic assemblages in streams with open canopy will exhibit more secondary productivity. We selected eight non-impacted headwater streams, four shaded and four with open canopy, all located in the Neotropical savannah (Cerrado) of southeastern Brazil. Open canopy streams consistently exhibited significantly higher eco-exergy and instant secondary production values, exemplifying that these streams may support more complex and productive benthic macroinvertebrate assemblages. Nevertheless, diversity indices and specific eco-exergy were not significantly different in shaded and open canopy streams. Since all the studied streams were selected for being considered as non-impacted, this suggests that the potential represented by more available food resources was not used to build a more complex dissipative structure. These results illustrate the role and importance of the canopy cover characteristics on the structure and functioning of benthic macroinvertebrate assemblages in tropical headwater streams, while autochthonous production appears to play a crucial role as food

  12. Towards a High Temporal Frequency Grass Canopy Thermal IR Model for Background Signatures

    Science.gov (United States)

    Ballard, Jerrell R., Jr.; Smith, James A.; Koenig, George G.

    2004-01-01

    In this paper, we present our first results towards understanding high temporal frequency thermal infrared response from a dense plant canopy and compare the application of our model, driven both by slowly varying, time-averaged meteorological conditions and by high frequency measurements of local and within canopy profiles of relative humidity and wind speed, to high frequency thermal infrared observations. Previously, we have employed three-dimensional ray tracing to compute the intercepted and scattered radiation fluxes and for final scene rendering. For the turbulent fluxes, we employed simple resistance models for latent and sensible heat with one-dimensional profiles of relative humidity and wind speed. Our modeling approach has proven successful in capturing the directional and diurnal variation in background thermal infrared signatures. We hypothesize that at these scales, where the model is typically driven by time-averaged, local meteorological conditions, the primary source of thermal variance arises from the spatial distribution of sunlit and shaded foliage elements within the canopy and the associated radiative interactions. In recent experiments, we have begun to focus on the high temporal frequency response of plant canopies in the thermal infrared at 1 second to 5 minute intervals. At these scales, we hypothesize turbulent mixing plays a more dominant role. Our results indicate that in the high frequency domain, the vertical profile of temperature change is tightly coupled to the within canopy wind speed In the results reported here, the canopy cools from the top down with increased wind velocities and heats from the bottom up at low wind velocities. .

  13. Canopy and leaf composition drive patterns of nutrient release from pruning residues in a coffee agroforest.

    Science.gov (United States)

    Tully, Katherine L; Lawrence, Deborah

    2012-06-01

    In a coffee agroforest, the crop is cultivated under the shade of fruit-bearing and nitrogen (N)-fixing trees. These trees are periodically pruned to promote flowering and fruiting as well as to make nutrients stored in tree biomass available to plants. We investigated the effect of canopy composition and substrate quality on decomposition rates and patterns of nutrient release from pruning residues in a coffee agroforest located in Costa Rica's Central Valley. Initial phosphorus (P) release was enhanced under a canopy composed solely of N-fixing, Erythrina poeppigiana compared to a mixed canopy of Erythrina and Musa acuminata (banana). Both initial and final N release were similar under the two canopy types. However, after five months of decomposition, a higher proportion of initial N had been released under the single canopy. Although patterns of decomposition and nutrient release were not predicted by initial substrate quality, mass loss in leaf mixtures rates were well predicted by mean mass loss of their component species. This study identifies specific pruning regimes that may regulate N and P release during crucial growth periods, and it suggests that strategic pruning can enhance nutrient availability. For example, during the onset of rapid fruit growth, a two-species mixture may release more P than a three-species mixture. However, by the time of the harvest, the two- and three-species mixtures have released roughly the same amount of N and P. These nutrients do not always follow the same pattern, as N release can be maximized in single-species substrates, while P release is often facilitated in species mixtures. Our study indicates the importance of management practices in mediating patterns of nutrient release. Future research should investigate how canopy composition and farm management can also mediate on-farm nutrient losses.

  14. Digital Shaded-Relief Image of Alaska

    Science.gov (United States)

    Riehle, J.R.; Fleming, Michael D.; Molnia, B.F.; Dover, J.H.; Kelley, J.S.; Miller, M.L.; Nokleberg, W.J.; Plafker, George; Till, A.B.

    1997-01-01

    Introduction One of the most spectacular physiographic images of the conterminous United States, and the first to have been produced digitally, is that by Thelin and Pike (USGS I-2206, 1991). The image is remarkable for its crispness of detail and for the natural appearance of the artificial land surface. Our goal has been to produce a shaded-relief image of Alaska that has the same look and feel as the Thelin and Pike image. The Alaskan image could have been produced at the same scale as its lower 48 counterpart (1:3,500,000). But by insetting the Aleutian Islands into the Gulf of Alaska, we were able to print the Alaska map at a larger scale (1:2,500,000) and about the same physical size as the Thelin and Pike image. Benefits of the 1:2,500,000 scale are (1) greater resolution of topographic features and (2) ease of reference to the U.S. Geological Survey (USGS) (1987) Alaska Map E and the statewide geologic map (Beikman, 1980), which are both 1:2,500,000 scale. Manually drawn, shaded-relief images of Alaska's land surface have long been available (for example, Department of the Interior, 1909; Raisz, 1948). The topography depicted on these early maps is mainly schematic. Maps showing topographic contours were first available for the entire State in 1953 (USGS, 1:250,000) (J.H. Wittmann, USGS, written commun., 1996). The Alaska Map E was initially released in 1954 in both planimetric (revised in 1973 and 1987) and shaded-relief versions (revised in 1973, 1987, and 1996); topography depicted on the shaded-relief version is based on the 1:250,000-scale USGS topographic maps. Alaska Map E was later modified to include hypsometric tinting by Raven Maps and Images (1989, revised 1993) as copyrighted versions. Other shaded-relief images were produced for The National Geographic Magazine (LaGorce, 1956; 1:3,000,000) or drawn by Harrison (1970; 1:7,500,000) for The National Atlas of the United States. Recently, the State of Alaska digitally produced a shaded-relief image

  15. ATOMLLL: atoms with shading and highlights

    International Nuclear Information System (INIS)

    Max, N.L.; y.

    1979-01-01

    The ATOMS program, written at Bell Telephone Laboratory, is capable of determining the visible portions of a scene consisting of interpenetrating spheres and cylinders, put together to represent space-filling or ball-and-stick molecular models. The Lawrence Livermore Laboratory version contains enhancements to add shading and highlights, and to render the spheres on film as ellipses, so they will appear round when projected in various wide-screen formats. The visible parts of each sphere or cylinder are shaded by a minicomputer controlling the film recorder, thus releasing the main computer from transferring the millions of intensity values for each frame. The minicomputer is microprogrammed with an efficient algorithm for the intensities, which uses the color look-up tables in the film recorder to store the reflectance as a function of angle of incidence. 8 references

  16. Composite shade guides and color matching.

    Science.gov (United States)

    Paolone, Gaetano; Orsini, Giovanna; Manauta, Jordi; Devoto, Walter; Putignano, Angelo

    2014-01-01

    Finding reliable systems that can help the clinician match the color of direct composite restorations is often an issue. After reviewing several composite shade guides available on the market and outlining their main characteristics and limits (unrealistic specimen thickness, not made with the same material the clinician will use, only a few allow to overlap enamel tabs on dentin ones), the authors evaluated the reliability of a system designed to produce self-made standardized "tooth-shaped" shade guide specimens. Small changes in composite enamel thickness may determine huge differences in esthetic outcomes. In conclusion, the results showed that all the specimens demonstrated comparable enamel thickness in all the examined areas (cervical, middle, incisal).

  17. Forests and their canopies: Archievements and horizons in canopy science

    Czech Academy of Sciences Publication Activity Database

    Nakamura, A.; Kitching, R. L.; Cao, M.; Creedy, T. J.; Fayle, Tom Maurice; Freiberg, M.; Hewitt, C. N.; Itioka, T.; Koh, L. P.; Ma, K.; Malhi, Y.; Mitchell, A.; Novotný, Vojtěch; Ozanne, C. M. P.; Song, L.; Wang, H.; Ashton, L. A.

    2017-01-01

    Roč. 32, č. 6 (2017), s. 438-451 ISSN 0169-5347 R&D Projects: GA ČR(CZ) GA16-09427S; GA ČR GB14-36098G EU Projects: European Commission(XE) 669609 - Diversity6continents Institutional support: RVO:60077344 Keywords : biodiversity * canopy * cranes Subject RIV: EH - Ecology, Behaviour OBOR OECD: Ecology Impact factor: 15.268, year: 2016 http://www.sciencedirect.com/science/article/pii/S0169534717300599

  18. Combined surface and volumetric occlusion shading

    KAUST Repository

    Schott, Matthias O.; Martin, Tobias; Grosset, A. V Pascal; Brownlee, Carson; Hollt, Thomas; Brown, Benjamin P.; Smith, Sean T.; Hansen, Charles D.

    2012-01-01

    In this paper, a method for interactive direct volume rendering is proposed that computes ambient occlusion effects for visualizations that combine both volumetric and geometric primitives, specifically tube shaped geometric objects representing streamlines, magnetic field lines or DTI fiber tracts. The proposed algorithm extends the recently proposed Directional Occlusion Shading model to allow the rendering of those geometric shapes in combination with a context providing 3D volume, considering mutual occlusion between structures represented by a volume or geometry. © 2012 IEEE.

  19. Combined surface and volumetric occlusion shading

    KAUST Repository

    Schott, Matthias O.

    2012-02-01

    In this paper, a method for interactive direct volume rendering is proposed that computes ambient occlusion effects for visualizations that combine both volumetric and geometric primitives, specifically tube shaped geometric objects representing streamlines, magnetic field lines or DTI fiber tracts. The proposed algorithm extends the recently proposed Directional Occlusion Shading model to allow the rendering of those geometric shapes in combination with a context providing 3D volume, considering mutual occlusion between structures represented by a volume or geometry. © 2012 IEEE.

  20. Comparison of accuracies of an intraoral spectrophotometer and conventional visual method for shade matching using two shade guide systems.

    Science.gov (United States)

    Parameswaran, Vidhya; Anilkumar, S; Lylajam, S; Rajesh, C; Narayan, Vivek

    2016-01-01

    This in vitro study compared the shade matching abilities of an intraoral spectrophotometer and the conventional visual method using two shade guides. The results of previous investigations between color perceived by human observers and color assessed by instruments have been inconclusive. The objectives were to determine accuracies and interrater agreement of both methods and effectiveness of two shade guides with either method. In the visual method, 10 examiners with normal color vision matched target control shade tabs taken from the two shade guides (VITAPAN Classical™ and VITAPAN 3D Master™) with other full sets of the respective shade guides. Each tab was matched 3 times to determine repeatability of visual examiners. The spectrophotometric shade matching was performed by two independent examiners using an intraoral spectrophotometer (VITA Easyshade™) with five repetitions for each tab. Results revealed that visual method had greater accuracy than the spectrophotometer. The spectrophotometer; however, exhibited significantly better interrater agreement as compared to the visual method. While VITAPAN Classical shade guide was more accurate with the spectrophotometer, VITAPAN 3D Master shade guide proved better with visual method. This in vitro study clearly delineates the advantages and limitations of both methods. There were significant differences between the methods with the visual method producing more accurate results than the spectrophotometric method. The spectrophotometer showed far better interrater agreement scores irrespective of the shade guide used. Even though visual shade matching is subjective, it is not inferior and should not be underrated. Judicious combination of both techniques is imperative to attain a successful and esthetic outcome.

  1. Exploring canopy structure and function as a potential mechanism of sustain carbon sequestration in aging forests

    Science.gov (United States)

    Fotis, A. T.; Curtis, P.; Ricart, R.

    2013-12-01

    The notion that old-growth forests reach carbon neutrality has recently been challenged, but the mechanisms responsible for continued productivity have remained elusive. Increases in canopy structural complexity, defined by high horizontal and vertical variability in leaf distribution (rugosity), has been proposed as a mechanism for sustained high rates of above ground net primary production (ANPPw) in forests up to ~170 years by enhancing light use efficiency (LUE) and nitrogen use efficiency (NUE). However, a detailed understanding of how rugosity affects resource distribution within and among trees leading to greater LUE and NUE is not known. We propose that leaves in high rugosity plots receive greater photosynthetic photon flux density (PPFD) than leaves in low rugosity plots, causing shifts from shade- to sun- adapted leaves into deeper portions of the canopy, which is thought to increase the photosynthetic capacity of individuals and lead to higher carbon assimilation in forests. The goal of this research was to: 1) quantify different canopy structural characteristics using a portable canopy LiDAR (PCL) and; 2) assess how these structural characteristics affect resource distribution and subsequent changes in leaf morphological, physiological and biochemical traits in three broadleaf species (e.g., Acer rubrum, Quercus rubra and Fagus grandifolia) and one conifer species (e.g., Pinus strobus) at different levels in the canopy in plots with similar leaf are index (LAI) but highly contrasting rugosity levels. We found that gap fraction had a strong positive correlation with rugosity. High rugosity plots had a bimodal distribution of LAI that was concentrated at the top and bottom of the canopy with an open midstory (between 10-50% of total canopy height) whereas low rugosity plots had a more even distribution of leaves. Leaf mass per area (LMA) of all broadleaved species had a strong positive correlation with cumulative gap fraction (P. strobus had a relatively

  2. Leaf Physiological and Morphological Responses to Shade in Grass-Stage Seedlings and Young Trees of Longleaf Pine

    Directory of Open Access Journals (Sweden)

    Lisa J. Samuelson

    2012-08-01

    Full Text Available Longleaf pine has been classified as very shade intolerant but leaf physiological plasticity to light is not well understood, especially given longleaf pine’s persistent seedling grass stage. We examined leaf morphological and physiological responses to light in one-year-old grass-stage seedlings and young trees ranging in height from 4.6 m to 6.3 m to test the hypothesis that young longleaf pine would demonstrate leaf phenotypic plasticity to light environment. Seedlings were grown in a greenhouse under ambient levels of photosynthetically active radiation (PAR or a 50% reduction in ambient PAR and whole branches of trees were shaded to provide a 50% reduction in ambient PAR. In seedlings, shading reduced leaf mass per unit area (LMA, the light compensation point, and leaf dark respiration (RD, and increased the ratio of light-saturated photosynthesis to RD and chlorophyll b and total chlorophyll expressed per unit leaf dry weight. In trees, shading reduced LMA, increased chlorophyll a, chlorophyll b and total chlorophyll on a leaf dry weight basis, and increased allocation of total foliar nitrogen to chlorophyll nitrogen. Changes in leaf morphological and physiological traits indicate a degree of shade tolerance that may have implications for even and uneven-aged management of longleaf pine.

  3. Variation in light-intercepting area and photosynthetic rate of sun and shade shoots of two Picea species in relation to the angle of incoming light.

    Science.gov (United States)

    Ishii, Hiroaki; Hamada, Yoko; Utsugi, Hajime

    2012-10-01

    We investigated the effects of sun- and shade-shoot architecture on the photosynthetic rates of two Picea species by applying light from various angles in the laboratory. Compared with sun shoots, shade shoots were characterized by lower mass allocation per light-intercepting area, less leaf mass per shoot mass, less mutual shading among leaves and more efficient allocation of chlorophyll to photosynthesis. The shoot silhouette to total leaf area ratio (STAR(ϕ)) decreased with increasing shoot inclination angle (ϕ, the shoot axis angle relative to the projection plane) and was consistently higher for the shade shoots. Morphological and physiological characteristics of the shade shoots resulted in maximum rates of net photosynthesis at ϕ = 0° (P(max,0)) similar to that of the sun shoots when expressed on a leaf mass, total leaf area and chlorophyll basis. When the angle of incoming light was varied, P(max,ϕ) per total leaf area (P(max,ϕ )/A(T)) of the shade shoots increased linearly with increasing STAR(ϕ), while P(max,ϕ) per shoot silhouette area did not change. In contrast, the response of the sun shoots was non-linear, and an optimum angle of incoming light was determined. Our results suggest that shade-shoot morphology is adaptive for utilizing diffuse light incoming from various angles, while sun-shoot morphology is adaptive for avoiding the negative effects of strong direct radiation and for enhancing light diffusion into the canopy. We propose that the angle of incoming light should be taken into account when estimating photosynthetic rates of sun shoots of conifer trees in the field.

  4. Relationship between natural tooth shade and skin colour.

    Science.gov (United States)

    Nourbakhsh, M; Mousavinejad, N; Adli, A R; Harati, M

    2013-06-01

    The purpose of this study was to assess the correlation of skin colour and tooth shade. One hundred and twenty six individuals aging between 18 to 25 years participated in this study. Colour of the maxillary central incisors was examined by VITA easy shade. Tooth shades were assigned to four ordinal values. Nivea Beauty Protect Foundation shade sample was used as a guide to assess facial skin colour Shin colours were also assigned to four ordinal values. Spearman test revealed that there was a significant relationship between tooth shade and skin colour Total co-relation factor was 51.6% (p men (p <0 .01). The highest tooth shade prevalence belonged to the second group and the highest skin colour prevalence was also in the second skin colour group.

  5. Shade selection performed by novice dental professionals and colorimeter.

    Science.gov (United States)

    Klemetti, E; Matela, A-M; Haag, P; Kononen, M

    2006-01-01

    The objective of this study was to test inter-observer variability in shade selection for porcelain restorations, using three different shade guides: Vita Lumin Vacuum, Vita 3D-Master and Procera. Nineteen young dental professionals acted as observers. The results were also compared with those of a digital colorimeter (Shade Eye Ex; Shofu, Japan). Regarding repeatability, no significant differences were found between the three shade guides, although repeatability was relatively low (33-43%). Agreement with the colorimetric results was also low (8-34%). In conclusion, shade selection shows moderate to great inter-observer variation. In teaching and standardizing the shade selection procedure, a digital colorimeter may be a useful educational tool.

  6. Impact of Manually Controlled Solar Shades on Indoor Visual Comfort

    Directory of Open Access Journals (Sweden)

    Jian Yao

    2016-07-01

    Full Text Available Daylight plays a significant role in sustainable building design. The purpose of this paper was to investigate the impact of manual solar shades on indoor visual comfort. A developed stochastic model for manual solar shades was modeled in Building Controls Virtual Test Bed, which was coupled with EnergyPlus for co-simulation. Movable solar shades were compared with two unshaded windows. Results show that movable solar shades have more than half of the working hours with a comfortable illuminance level, which is about twice higher than low-e windows, with a less significant daylight illuminance fluctuation. For glare protection, movable solar shades increase comfortable visual conditions by about 20% compared to low-e windows. Moreover, the intolerable glare perception could be reduced by more than 20% for movable solar shades.

  7. Sunscreening fungal pigments influence the vertical gradient of pendulous lichens in boreal forest canopies.

    Science.gov (United States)

    Färber, Leonie; Sølhaug, Knut Asbjorn; Esseen, Per-Anders; Bilger, Wolfgang; Gauslaa, Yngvar

    2014-06-01

    Pendulous lichens dominate canopies of boreal forests, with dark Bryoria species in the upper canopy vs. light Alectoria and Usnea species in lower canopy. These genera offer important ecosystem services such as winter forage for reindeer and caribou. The mechanism behind this niche separation is poorly understood. We tested the hypothesis that species-specific sunscreening fungal pigments protect underlying symbiotic algae differently against high light, and thus shape the vertical canopy gradient of epiphytes. Three pale species with the reflecting pigment usnic acid (Alectoria sarmentosa, Usnea dasypoga, U. longissima) and three with dark, absorbing melanins (Bryoria capillaris, B. fremontii, B. fuscescens) were compared. We subjected the lichens to desiccation stress with and without light, and assessed their performance with chlorophyll fluorescence. Desiccation alone only affected U. longissima. By contrast, light in combination with desiccation caused photoinhibitory damage in all species. Usnic lichens were significantly more susceptible to light during desiccation than melanic ones. Thus, melanin is a more efficient light-screening pigment than usnic acid. Thereby, the vertical gradient of pendulous lichens in forest canopies is consistent with a shift in type and functioning of sunscreening pigments, from high-light-tolerant Bryoria in the upper to susceptible Alectoria and Usnea in the lower canopy.

  8. Differences in Proteins Synthesized in Needles of Unshaded and Shaded Pinus ponderosa var Scopulorum Seedlings during Prolonged Drought 1

    Science.gov (United States)

    Vance, Nan C.; Copes, Donald O.; Zaerr, Joe B.

    1990-01-01

    Proteins were radiolabeled and extracted from needles of Pinus ponderosa var scopulorum (Dougl. ex Laws.) seedlings progressively drought-stressed for about 1 month. A set of novel, low molecular weight proteins was detected in fluorographs of two-dimensional gels when relative water content of needles fell below 70%. Their synthesis was undetectable in the fully recovered seedlings within 48 hours after rewatering. In similarly stressed seedlings that were shaded to 10% full light, the low molecular weight polypeptides were not detected or appeared at very low levels. The shaded seedlings, in which drought tolerance was reduced, did not recover upon termination of the drought. The results suggest that protein synthesis induced by water deficit in drought-tolerant seedlings may contribute to resisting the effects of cellular dehydration. Images Figure 1 Figure 2 PMID:16667397

  9. STUDIES OF SHADING LEVELS AND NUTRITION SOURCES ON GROWTH, YIELD

    Directory of Open Access Journals (Sweden)

    Edi Purwanto

    2011-10-01

    Full Text Available Growth and biochemical content of medicinal crops are influenced by agroecosystems characteristics . The objective of this research was to determine the optimum shading level and type of fertilizer as sources of nutrition on the growth, yield, and andrographolide content of sambiloto. The experiment used Split Plot Design with basic design of Randomized Complete Block Design arranged with two treatment factors, with three replications. The first factor as the main plot was shading levels, namely without shading, 25% shading, 50% shading, and 75% shading. The second factor as the sub plot was sources of nutrition reprented by type of fertilizer, namely NPK fertilizer, cow stable fertilizer, and compost fertilizer. The result of research indicated that shading level and the kind of nutrition influenced some growth and yield variables such as number of leaves, number of branches, plant height, plant dry weight and simplisia weight, and andrographolide content. Interaction of shading level at 25% and straw compost fertilizer performed best in growth characteristics, while the highest andrographolide content resulted from the treatment combination of 50% shading level and straw compost fertilizer.

  10. Effects of shading on Vallisneria natans (Lour. H. Hara growth

    Directory of Open Access Journals (Sweden)

    Fox A.D.

    2013-08-01

    Full Text Available Effects of surface shading were measured on above- and below-ground biomass and fruit production of Vallisneria natans (Lour. H. Hara plants grown from seed in replicated microcosm experiments, based on a control (no shading and four treatments (25%, 50%, 75% and 90% shading. Above- and below-ground biomass was significantly reduced at treatments above 50% shading and first pistillate and staminate florescence dates were significantly delayed above 75% and 50% shading, respectively. Ratios of mature to unripe fruits produced (both in number or dry weight did not differ between shading treatments, but dry weight fruit production was significantly reduced at 90% shading. We conclude that above 50% surface shading, V. natans plants suffer reductions in accumulated biomass and investment in sexual reproduction. We contend that recent expansions in the extent of the native floating water chestnut Trapa spp. at seasonally inundated wetlands in the Yangtze River floodplain could, by shading, have contributed to the reduction in annual biomass and seed production of V. natans, contributing to declines in distribution and abundance.

  11. OpenGL 4 shading language cookbook

    CERN Document Server

    Wolff, David

    2013-01-01

    OpenGL Shading Language 4 Cookbook is a hands-on guide that gets straight to the point - actually creating graphics, instead of just theoretical learning. Each recipe is specifically tailored to satisfy your appetite for producing real-time 3-D graphics using the latest GLSL specification.This book is for OpenGL programmers looking to use the modern features of GLSL 4 to create real-time, three-dimensional graphics. Familiarity with OpenGL programming, along with the typical 3D coordinate systems, projections, and transformations is assumed. It can also be useful for experienced GLSL programme

  12. Bali, Shaded Relief and Colored Height

    Science.gov (United States)

    2004-01-01

    The volcanic nature of the island of Bali is evident in this shaded relief image generated with data from the Shuttle Radar Topography Mission (SRTM).Bali, along with several smaller islands, make up one of the 27 Provinces of Indonesia. It lies over a major subduction zone where the Indo-Australian tectonic plate collides with the Sunda plate, creating one of the most volcanically active regions on the planet.The most significant feature on Bali is Gunung Agung, the symmetric, conical mountain at the right-center of the image. This 'stratovolcano,' 3,148 meters (10,308 feet) high, is held sacred in Balinese culture, and last erupted in 1963 after being dormant and thought inactive for 120 years. This violent event resulted in over 1,000 deaths, and coincided with a purification ceremony called Eka Dasa Rudra, meant to restore the balance between nature and man. This most important Balinese rite is held only once per century, and the almost exact correspondence between the beginning of the ceremony and the eruption is though to have great religious significance.Two visualization methods were combined to produce the image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction, so that northwest slopes appear bright and southeast slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations.Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot

  13. Colored Height and Shaded Relief, Kamchatka Peninsula

    Science.gov (United States)

    2002-01-01

    Russia's Kamchatka Peninsula, lying between the Sea of Okhotsk to the west and the Bering Sea and Pacific Ocean to the east, is one of the most active volcanic regions along the Pacific Ring of Fire. It covers an area about the size of Colorado but contains more than 100 volcanoes stretching across the 1000-kilometer-long (620-mile-long) land mass. A dozen or more of these have active vents, with the youngest located along the eastern half of the peninsula. This color-coded shaded relief image, generated with data from the Shuttle Radar Topography Mission (SRTM), shows Kamchatka's volcanic nature to dramatic effect.Kliuchevskoi, one of the most active and renowned volcanoes in the world, dominates the main cluster of volcanoes called the Kliuchi group, visible as a circular feature in the center-right of the image. The two other main volcanic ranges lie along northeast-southwest lines, with the older, less active range occupying the center and western half of Kamchatka. The younger, more active belt begins at the southernmost point of the peninsula and continues upward along the Pacific coastline.Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the north-south direction, so northern slopes appear bright and southern slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and brown to white at the highest elevations.The Shuttle Radar Topography Mission flew aboard the Space Shuttle Endeavour, launched on February 11, 2000. The mission used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar that flew twice on the Space Shuttle Endeavour in 1994. The Shuttle Radar Topography Mission was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (200

  14. Sinai Peninsula, Shaded Relief and Colored Height

    Science.gov (United States)

    2004-01-01

    The Sinai Peninsula, located between Africa and Asia, is a result of those two continents pulling apart from each other. Earth's crust is cracking, stretching, and lowering along the two northern branches of the Red Sea, namely the Gulf of Suez, seen here on the west (left), and the Gulf of Aqaba, seen to the east (right). This color-coded shaded relief image shows the triangular nature of the peninsula, with the coast of the Mediterranean Sea forming the northern side of the triangle. The Suez Canal can be seen as the narrow vertical blue line in the upper left connecting the Red Sea to the Mediterranean. The peninsula is divided into three distinct parts; the northern region consisting chiefly of sandstone, plains and hills, the central area dominated by the Tih Plateau, and the mountainous southern region where towering peaks abound. Much of the Sinai is deeply dissected by river valleys, or wadis, that eroded during an earlier geologic period and break the surface of the plateau into a series of detached massifs with a few scattered oases. Two visualization methods were combined to produce the image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction, so that northwest slopes appear bright and southeast slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations. Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed

  15. Fine Root Abundance and Dynamics of Stone Pine (Pinus cembra) at the Alpine Treeline Is Not Impaired by Self-shading.

    Science.gov (United States)

    Kubisch, Petra; Leuschner, Christoph; Coners, Heinz; Gruber, Andreas; Hertel, Dietrich

    2017-01-01

    Low temperatures are crucial for the formation of the alpine treeline worldwide. Since soil temperature in the shade of tree canopies is lower than in open sites, it was assumed that self-shading may impair the trees' root growth performance. While experiments with tree saplings demonstrate root growth impairment at soil temperatures below 5-7°C, field studies exploring the soil temperature - root growth relationship at the treeline are missing. We recorded soil temperature and fine root abundance and dynamics in shaded and sun-exposed areas under canopies of isolated Pinus cembra trees at the alpine treeline. In contrast to the mentioned assumption, we found more fine root biomass and higher fine root growth in colder than in warmer soil areas. Moreover, colder areas showed higher fine root turnover and thus lower root lifespan than warmer places. We conclude that P. cembra balances enhanced fine root mortality in cold soils with higher fine root activity and by maintaining higher fine root biomass, most likely as a response to shortage in soil resource supply. The results from our study highlight the importance of in situ measurements on mature trees to understand the fine root response and carbon allocation pattern to the thermal growth conditions at the alpine treeline.

  16. Ozone Flux Measurement and Modelling on Leaf/Shoot and Canopy Scale

    Directory of Open Access Journals (Sweden)

    Ludger Grünhage

    calculated by SVAT models often based on the energy balance of the soil-vegetation-atmosphere system and on the big-leaf concept. This latter assumes the canopy as equivalent to a single leaf having a leaf area equal to the total area of all the plant’s leaves and lying at a certain height above the ground. The complexity of SVAT models ranges from one-dimensional to three-dimensional models. The most used are one-dimensional models in single-layer, dual-source or multi-layer version. The main uncertainties in flux modelling are currently associated to the estimation of the non-stomatal flux component and to the up-scaling process from leaf to canopy and stand level. For the latter a separate representation of sunlit and shaded leaves is recommended.

  17. Mapping forest canopy fuels in Yellowstone National Park using lidar and hyperspectral data

    Science.gov (United States)

    Halligan, Kerry Quinn

    The severity and size of wildland fires in the forested western U.S have increased in recent years despite improvements in fire suppression efficiency. This, along with increased density of homes in the wildland-urban interface, has resulted in high costs for fire management and increased risks to human health, safety and property. Crown fires, in comparison to surface fires, pose an especially high risk due to their intensity and high rate of spread. Crown fire models require a range of quantitative fuel parameters which can be difficult and costly to obtain, but advances in lidar and hyperspectral sensor technologies hold promise for delivering these inputs. Further research is needed, however, to assess the strengths and limitations of these technologies and the most appropriate analysis methodologies for estimating crown fuel parameters from these data. This dissertation focuses on retrieving critical crown fuel parameters, including canopy height, canopy bulk density and proportion of dead canopy fuel, from airborne lidar and hyperspectral data. Remote sensing data were used in conjunction with detailed field data on forest parameters and surface reflectance measurements. A new method was developed for retrieving Digital Surface Model (DSM) and Digital Canopy Models (DCM) from first return lidar data. Validation data on individual tree heights demonstrated the high accuracy (r2 0.95) of the DCMs developed via this new algorithm. Lidar-derived DCMs were used to estimate critical crown fire parameters including available canopy fuel, canopy height and canopy bulk density with linear regression model r2 values ranging from 0.75 to 0.85. Hyperspectral data were used in conjunction with Spectral Mixture Analysis (SMA) to assess fuel quality in the form of live versus dead canopy proportions. Severity and stage of insect-caused forest mortality were estimated using the fractional abundance of green vegetation, non-photosynthetic vegetation and shade obtained from

  18. Fifty shades of exploitation: Fan labor and Fifty Shades of Grey

    Directory of Open Access Journals (Sweden)

    Bethan Jones

    2014-03-01

    Full Text Available This exploration of the debates that have taken place in fandom over the ethics of pulling fan fiction and publishing it as original work draws on the notion of the fannish gift economy, which postulates that gifts such as fan fiction and fan art have value in the fannish community because they are designed to create and cement its social structure. Tension exists between fans who subscribe to the notion of a fannish gift economy and those who exploit fandom by using it to sell their pulled-to-publish works. An examination of E. L. James's 2012 Fifty Shades trilogy (comprising the books Fifty Shades of Grey, Fifty Shades Darker, and Fifty Shades Freed, which began as Twilight fan fiction, in addition to Twilight fan art sold through sites such as Redbubble and Etsy, demonstrates a tension between the two modes of fan expression: sale of artworks appears to be an acceptable practice in fandom, but the commercial sale of fan fic, even when marketed as original fiction, is widely contested.

  19. Canopy Dynamics in Nanoscale Ionic Materials

    KAUST Repository

    Jespersen, Michael L.

    2010-07-27

    Nanoscale ionic materials (NIMS) are organic - inorganic hybrids in which a core nanostructure is functionalized with a covalently attached corona and an ionically tethered organic canopy. NIMS are engineered to be liquids under ambient conditions in the absence of solvent and are of interest for a variety of applications. We have used nuclear magnetic resonance (NMR) relaxation and pulse-field gradient (PFG) diffusion experiments to measure the canopy dynamics of NIMS prepared from 18-nm silica cores modified by an alkylsilane monolayer possessing terminal sulfonic acid functionality, paired with an amine-terminated ethylene oxide/propylene oxide block copolymer canopy. Carbon NMR studies show that the block copolymer canopy is mobile both in the bulk and in the NIMS and that the fast (ns) dynamics are insensitive to the presence of the silica nanoparticles. Canopy diffusion in the NIMS is slowed relative to the neat canopy, but not to the degree predicted from the diffusion of hard-sphere particles. Canopy diffusion is not restricted to the surface of the nanoparticles and shows unexpected behavior upon addition of excess canopy. Taken together, these data indicate that the liquid-like behavior in NIMS is due to rapid exchange of the block copolymer canopy between the ionically modified nanoparticles. © 2010 American Chemical Society.

  20. Canopy Dynamics in Nanoscale Ionic Materials

    KAUST Repository

    Jespersen, Michael L.; Mirau, Peter A.; Meerwall, Ernst von; Vaia, Richard A.; Rodriguez, Robert; Giannelis, Emmanuel P.

    2010-01-01

    Nanoscale ionic materials (NIMS) are organic - inorganic hybrids in which a core nanostructure is functionalized with a covalently attached corona and an ionically tethered organic canopy. NIMS are engineered to be liquids under ambient conditions in the absence of solvent and are of interest for a variety of applications. We have used nuclear magnetic resonance (NMR) relaxation and pulse-field gradient (PFG) diffusion experiments to measure the canopy dynamics of NIMS prepared from 18-nm silica cores modified by an alkylsilane monolayer possessing terminal sulfonic acid functionality, paired with an amine-terminated ethylene oxide/propylene oxide block copolymer canopy. Carbon NMR studies show that the block copolymer canopy is mobile both in the bulk and in the NIMS and that the fast (ns) dynamics are insensitive to the presence of the silica nanoparticles. Canopy diffusion in the NIMS is slowed relative to the neat canopy, but not to the degree predicted from the diffusion of hard-sphere particles. Canopy diffusion is not restricted to the surface of the nanoparticles and shows unexpected behavior upon addition of excess canopy. Taken together, these data indicate that the liquid-like behavior in NIMS is due to rapid exchange of the block copolymer canopy between the ionically modified nanoparticles. © 2010 American Chemical Society.

  1. Identifying the environmental factors that effect within canopy BVOC loss using a multilevel canopy model

    Science.gov (United States)

    Chan, W. S.; Fuentes, J. D.; Lerdau, M.

    2010-12-01

    This presentation will provide research findings to evaluate the hypothesis that the loss of biogenic volatile organic compound (BVOC) within plant canopies is dynamic and depends on factors such as plant canopy architecture (height and leaf area distribution), atmospheric turbulence, concentration of oxidants (OH, O3, NO3), and the reactivity of BVOC species. Results will be presented from a new one dimensional, multilevel canopy model that couples algorithms for canopy microclimate, leaf physiology, BVOC emission, turbulent transport, and atmospheric chemistry to investigate the relative importance of factors that impact BVOC loss within a forest canopy. Model sensitivity tests will be presented and discussed to identify factors driving canopy loss. Results show isoprene and monoterpene canopy losses as high as 9 and 18%, respectively, for tall canopies during the daytime. We hypothesize that canopy height and wind speed (i.e. canopy residence time) may be the most important in dictating within-canopy loss. This work will reduce the error in bottom-up flux estimates of BVOCs and ultimately improve parameterizations of BVOC sources in air quality models by accounting for within canopy processes.

  2. VitiCanopy: A Free Computer App to Estimate Canopy Vigor and Porosity for Grapevine.

    Science.gov (United States)

    De Bei, Roberta; Fuentes, Sigfredo; Gilliham, Matthew; Tyerman, Steve; Edwards, Everard; Bianchini, Nicolò; Smith, Jason; Collins, Cassandra

    2016-04-23

    Leaf area index (LAI) and plant area index (PAI) are common and important biophysical parameters used to estimate agronomical variables such as canopy growth, light interception and water requirements of plants and trees. LAI can be either measured directly using destructive methods or indirectly using dedicated and expensive instrumentation, both of which require a high level of know-how to operate equipment, handle data and interpret results. Recently, a novel smartphone and tablet PC application, VitiCanopy, has been developed by a group of researchers from the University of Adelaide and the University of Melbourne, to estimate grapevine canopy size (LAI and PAI), canopy porosity, canopy cover and clumping index. VitiCanopy uses the front in-built camera and GPS capabilities of smartphones and tablet PCs to automatically implement image analysis algorithms on upward-looking digital images of canopies and calculates relevant canopy architecture parameters. Results from the use of VitiCanopy on grapevines correlated well with traditional methods to measure/estimate LAI and PAI. Like other indirect methods, VitiCanopy does not distinguish between leaf and non-leaf material but it was demonstrated that the non-leaf material could be extracted from the results, if needed, to increase accuracy. VitiCanopy is an accurate, user-friendly and free alternative to current techniques used by scientists and viticultural practitioners to assess the dynamics of LAI, PAI and canopy architecture in vineyards, and has the potential to be adapted for use on other plants.

  3. Simultaneous improvement in water use, productivity and albedo through canopy structural modification

    Science.gov (United States)

    Drewry, Darren; Kumar, Praveen; Long, Stephen

    2015-04-01

    Agricultural lands provide a tremendous opportunity to address challenges at the intersection of food and water security and climate change. Global demand for the major grain and seed crops is beginning to outstrip production, while population growth and the expansion of the global middle class have motivated calls for a doubling of food production by the middle of this century. This is occurring as yield gains for the major food crops have stagnated. At current rates of yield improvement this doubling will not be achieved. Plants have evolved to maximize the capture of radiation in the upper leaves, resulting in sub-optimal monoculture crop fields for maximizing productivity and other biogeophysical services. Using the world's most important protein crop, soybean, as an example, we show that by applying numerical optimization to a micrometeorological crop canopy model that significant, simultaneous gains in water use, productivity and reflectivity are possible with no increased demand on resources. Here we apply the MLCan multi-layer canopy biophysical model, which vertically resolves the radiation and micro-environmental variations that stimulate biochemical and ecophysiological functions that govern canopy-atmosphere exchange processes. At each canopy level photosynthesis, stomatal conductance, and energy balance are solved simultaneously for shaded and sunlit foliage. A multi-layer sub-surface model incorporates water availability as a function of root biomass distribution. MLCan runs at sub-hourly temporal resolution, allowing it to capture variability in CO2, water and energy exchange as a function of environmental variability. By modifying total canopy leaf area, its vertical distribution, leaf angle, and shortwave radiation reflectivity, all traits available in most major crop germplasm collections, we show that increases in either productivity (7%), water use (13%) or albedo (34%) could be achieved with no detriment to the other objectives, under climate

  4. Ground based remote sensing and physiological measurements provide novel insights into canopy photosynthetic optimization in arctic shrubs

    Science.gov (United States)

    Magney, T. S.; Griffin, K. L.; Boelman, N.; Eitel, J.; Greaves, H.; Prager, C.; Logan, B.; Oliver, R.; Fortin, L.; Vierling, L. A.

    2014-12-01

    Because changes in vegetation structure and function in the Arctic are rapid and highly dynamic phenomena, efforts to understand the C balance of the tundra require repeatable, objective, and accurate remote sensing methods for estimating aboveground C pools and fluxes over large areas. A key challenge addressing the modelling of aboveground C is to utilize process-level information from fine-scale studies. Utilizing information obtained from high resolution remote sensing systems could help to better understand the C source/sink strength of the tundra, which will in part depend on changes in photosynthesis resulting from the partitioning of photosynthetic machinery within and among deciduous shrub canopies. Terrestrial LiDAR and passive hyperspectral remote sensing measurements offer an effective, repeatable, and scalable method to understand photosynthetic performance and partitioning at the canopy scale previously unexplored in arctic systems. Using a 3-D shrub canopy model derived from LiDAR, we quantified the light regime of leaves within shrub canopies to gain a better understanding of how light interception varies in response to the Arctic's complex radiation regime. This information was then coupled with pigment sampling (i.e., xanthophylls, and Chl a/b) to evaluate the optimization of foliage photosynthetic capacity within shrub canopies due to light availability. In addition, a lab experiment was performed to validate evidence of canopy level optimization via gradients of light intensity and leaf light environment. For this, hyperspectral reflectance (photochemical reflectance index (PRI)), and solar induced fluorescence (SIF)) was collected in conjunction with destructive pigment samples (xanthophylls) and chlorophyll fluorescence measurements in both sunlit and shaded canopy positions.

  5. Development and bloom in hybrids of wild passion fruit cultivated in different types of pots and shading levels

    Directory of Open Access Journals (Sweden)

    Eileen Azevedo Santos

    2012-04-01

    Full Text Available Ornamental hybrids of passion flowers are thoroughly diffused in many countries and used in the decoration of houses and gardens. However, the cultivation of ornamental passion fruits practically unexploited in Brazil. This study aimed at evaluating the growth and blooming of F1 hybrids of Passiflora L. (P. sublanceolata J.M. MacDougal [ex P. palmeri var. sublanceolata Killip] vs. P. foetida var. foetida L. cultivated in ceramic and concrete pots under different shading levels. The vegetative and flower evaluations were carried out weekly, in clonal cuttings 60 days after rooting. The height, leaf length and width, the number of internodes and leaves and stem diameter were evaluated using a randomized complete design in a factorial scheme which corresponded to two genotypes, two types of pot, three shading levels (25 %, 50 %, 75 % and seven weeks of evaluation, with four replications. For the variable number of flowers, the same experimental design was adopted. However, the number of evaluations was modified for three periods, but this was not considered for the flower diameter and leaf area. The shading levels of 25 % and 50 % were the most favorable to the growth in height, whereas hybrid genotypes under 25 % shade had greater increase in the number of leaves, internodes and stem diameter, showing tolerance to moderate shade. The higher values for length, width and leaf area were observed at 75 % shade. The greatest number of flowers was verified at 25 % shadow in concrete pots. As for the types of pot, the ceramic ones were more favorable to the growth of hybrid plants during the first weeks of acclimatization to the treatments, and the concrete ones were more propitious to blooming. Thus, the use of hybrid plants in concrete pots for the ornamentation of internal environments is recommended, if they are well illuminated.

  6. Twenty-Two Years of Warming, Fertilisation and Shading of Subarctic Heath Shrubs Promote Secondary Growth and Plasticity but Not Primary Growth

    Science.gov (United States)

    Campioli, Matteo; Leblans, Niki; Michelsen, Anders

    2012-01-01

    Most manipulation experiments simulating global change in tundra were short-term or did not measure plant growth directly. Here, we assessed the growth of three shrubs (Cassiope tetragona, Empetrum hermaphroditum and Betula nana) at a subarctic heath in Abisko (Northern Sweden) after 22 years of warming (passive greenhouses), fertilisation (nutrients addition) and shading (hessian fabric), and compare this to observations from the first decade of treatment. We assessed the growth rate of current-year leaves and apical stem (primary growth) and cambial growth (secondary growth), and integrated growth rates with morphological measurements and species coverage. Primary- and total growth of Cassiope and Empetrum were unaffected by manipulations, whereas growth was substantially reduced under fertilisation and shading (but not warming) for Betula. Overall, shrub height and length tended to increase under fertilisation and warming, whereas branching increased mostly in shaded Cassiope. Morphological changes were coupled to increased secondary growth under fertilisation. The species coverage showed a remarkable increase in graminoids in fertilised plots. Shrub response to fertilisation was positive in the short-term but changed over time, likely because of an increased competition with graminoids. More erected postures and large, canopies (requiring enhanced secondary growth for stem reinforcement) likely compensated for the increased light competition in Empetrum and Cassiope but did not avoid growth reduction in the shade intolerant Betula. The impact of warming and shading on shrub growth was more conservative. The lack of growth enhancement under warming suggests the absence of long-term acclimation for processes limiting biomass production. The lack of negative effects of shading on Cassiope was linked to morphological changes increasing the photosynthetic surface. Overall, tundra shrubs showed developmental plasticity over the longer term. However, such plasticity

  7. Solar Shading System Based on Daylight Directing Glass Lamellas

    DEFF Research Database (Denmark)

    Laustsen, Jacob Birck; Santos, Inês; Svendsen, Svend

    2008-01-01

    The overheating problems in office buildings must be solved with efficient solar shadings in order to reduce the energy demand for cooling and ventilation. At the same time the solar shading should not reduce the daylight level in the building on overcast days because it would result in a lower...

  8. Influence of shading on container-grown flowering dogwoods

    Science.gov (United States)

    Bare root dogwoods can be successfully grown when transplanted into a container production system. Shade treatments regardless of color or density did have an effect on the plant growth of Cherokee Brave™ and Cherokee Princess dogwood. Plants grown under 50% black and 50% white shade had more heigh...

  9. Leaf Wetness within a Lily Canopy

    NARCIS (Netherlands)

    Jacobs, A.F.G.; Heusinkveld, B.G.; Klok, E.J.

    2005-01-01

    A wetness duration experiment was carried out within a lily field situated adjacent to coastal dunes in the Netherlands. A within-canopy model was applied to simulate leaf wetness in three layers, with equal leaf area indices, within the canopy. This simulation model is an extension of an existing

  10. Plant canopy characteristics effect on spray deposition

    Science.gov (United States)

    While it is common for applicators to standardize their application parameters to minimize changes in settings during a season, this practice does not necessarily provide the best delivery when targeting different types of plant canopies and different zones within the canopy. The objective of this w...

  11. The impact of modifying antenna size of photosystem II on canopy photosynthetic efficiency – development of a new canopy photosynthesis model scaling from metabolism to canopy level processes

    Science.gov (United States)

    Canopy photosynthesis describes photosynthesis of an entire crop field and positively correlates with biomass production. Much effort in crop breeding has focused on improving canopy architecture and hence light distribution inside the canopy. Here, we develop a new integrated canopy photosynthesis ...

  12. Establishment of the Relationship between the Photochemical Reflectance Index and Canopy Light Use Efficiency Using Multi-angle Hyperspectral Observations

    Science.gov (United States)

    Zhang, Qian; Chen, Jing; Zhang, Yongguang; Qiu, Feng; Fan, Weiliang; Ju, Weimin

    2017-04-01

    The gross primary production (GPP) of terrestrial ecosystems constitutes the largest global land carbon flux and exhibits significant spatial and temporal variations. Due to its wide spatial coverage, remote sensing technology is shown to be useful for improving the estimation of GPP in combination with light use efficiency (LUE) models. Accurate estimation of LUE is essential for calculating GPP using remote sensing data and LUE models at regional and global scales. A promising method used for estimating LUE is the photochemical reflectance index (PRI = (R531-R570)/(R531 + R570), where R531 and R570 are reflectance at wavelengths 531 and 570 nm) through remote sensing. However, it has been documented that there are certain issues with PRI at the canopy scale, which need to be considered systematically. For this purpose, an improved tower-based automatic canopy multi-angle hyperspectral observation system was established at the Qianyanzhou flux station in China since January of 2013. In each 15-minute observation cycle, PRI was observed at four view zenith angles fixed at solar zenith angle and (37°, 47°, 57°) or (42°, 52°, 62°) in the azimuth angle range from 45° to 325° (defined from geodetic north). To improve the ability of directional PRI observation to track canopy LUE, the canopy is treated as two-big leaves, i.e. sunlit and shaded leaves. On the basis of a geometrical optical model, the observed canopy reflectance for each view angle is separated to four components, i.e. sunlit and shaded leaves and sunlit and shaded backgrounds. To determine the fractions of these four components at each view angle, three models based on different theories are tested for simulating the fraction of sunlit leaves. Finally, a ratio of canopy reflectance to leaf reflectance is used to represent the fraction of sunlit leaves, and the fraction of shaded leaves is calculated with the four-scale geometrical optical model. Thus, sunlit and shaded PRI are estimated using

  13. A photosynthesis-based two-leaf canopy stomatal ...

    Science.gov (United States)

    A coupled photosynthesis-stomatal conductance model with single-layer sunlit and shaded leaf canopy scaling is implemented and evaluated in a diagnostic box model with the Pleim-Xiu land surface model (PX LSM) and ozone deposition model components taken directly from the meteorology and air quality modeling system—WRF/CMAQ (Weather Research and Forecast model and Community Multiscale Air Quality model). The photosynthesis-based model for PX LSM (PX PSN) is evaluated at a FLUXNET site for implementation against different parameterizations and the current PX LSM approach with a simple Jarvis function (PX Jarvis). Latent heat flux (LH) from PX PSN is further evaluated at five FLUXNET sites with different vegetation types and landscape characteristics. Simulated ozone deposition and flux from PX PSN are evaluated at one of the sites with ozone flux measurements. Overall, the PX PSN simulates LH as well as the PX Jarvis approach. The PX PSN, however, shows distinct advantages over the PX Jarvis approach for grassland that likely result from its treatment of C3 and C4 plants for CO2 assimilation. Simulations using Moderate Resolution Imaging Spectroradiometer (MODIS) leaf area index (LAI) rather than LAI measured at each site assess how the model would perform with grid averaged data used in WRF/CMAQ. MODIS LAI estimates degrade model performance at all sites but one site having exceptionally old and tall trees. Ozone deposition velocity and ozone flux along with LH

  14. Shaded Relief of Rio Sao Francisco, Brazil

    Science.gov (United States)

    2000-01-01

    This topographic image acquired by SRTM shows an area south of the Sao Francisco River in Brazil. The scrub forest terrain shows relief of about 400 meters (1300 feet). Areas such as these are difficult to map by traditional methods because of frequent cloud cover and local inaccessibility. This region has little topographic relief, but even subtle changes in topography have far-reaching effects on regional ecosystems. The image covers an area of 57 km x 79 km and represents one quarter of the 225 km SRTM swath. Colors range from dark blue at water level to white and brown at hill tops. The terrain features that are clearly visible in this image include tributaries of the Sao Francisco, the dark-blue branch-like features visible from top right to bottom left, and on the left edge of the image, and hills rising up from the valley floor. The San Francisco River is a major source of water for irrigation and hydroelectric power. Mapping such regions will allow scientists to better understand the relationships between flooding cycles, forestation and human influences on ecosystems.This shaded relief image was generated using topographic data from the Shuttle Radar Topography Mission. A computer-generated artificial light source illuminates the elevation data to produce a pattern of light and shadows. Slopes facing the light appear bright, while those facing away are shaded. On flatter surfaces, the pattern of light and shadows can reveal subtle features in the terrain. Shaded relief maps are commonly used in applications such as geologic mapping and land use planning.The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200

  15. Shaded relief of Bahia State, Brazil

    Science.gov (United States)

    2000-01-01

    This topographic image is the first to show the full 240-kilometer-wide (150 mile)swath collected by the Shuttle Radar Topography Mission (SRTM). The area shown is in the state of Bahia in Brazil. The semi-circular mountains along the left side of the image are the Serra Da Jacobin, which rise to 1100 meters (3600 feet) above sea level. The total relief shown is approximately 800 meters (2600 feet). The top part of the image is the Sertao, a semi-arid region, that is subject to severe droughts during El Nino events. A small portion of the San Francisco River, the longest river (1609 kilometers or 1000 miles) entirely within Brazil, cuts across the upper right corner of the image. This river is a major source of water for irrigation and hydroelectric power. Mapping such regions will allow scientists to better understand the relationships between flooding cycles, drought and human influences on ecosystems.This shaded relief image was generated using topographic data from the Shuttle Radar Topography Mission. A computer-generated artificial light source illuminates the elevation data to produce a pattern of light and shadows. Slopes facing the light appear bright, while those facing away are shaded. On flatter surfaces, the pattern of light and shadows can reveal subtle features in the terrain. Colors show the elevation as measured by SRTM. Colors range from green at the lowest elevations to reddish at the highest elevations. Shaded relief maps are commonly used in applications such as geologic mapping and land use planning.The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging

  16. Colored Height and Shaded Relief, Central America

    Science.gov (United States)

    2002-01-01

    Panama, Costa Rica, Nicaragua, El Salvador, Honduras, Guatemala, Belize, southern Mexico and parts of Cuba and Jamaica are all seen in this image from NASA's Shuttle Radar Topography Mission. The dominant feature of the northern part of Central America is the Sierra Madre Range, spreading east from Mexico between the narrow Pacific coastal plain and the limestone lowland of the Yucatan Peninsula. Parallel hill ranges sweep across Honduras and extend south, past the Caribbean Mosquito Coast to lakes Managua and Nicaragua. The Cordillera Central rises to the south, gradually descending to Lake Gatun and the Isthmus of Panama. A highly active volcanic belt runs along the Pacific seaboard from Mexico to Costa Rica.High-quality satellite imagery of Central America has, until now, been difficult to obtain due to persistent cloud cover in this region of the world. The ability of SRTM to penetrate clouds and make three-dimensional measurements has allowed the generation of the first complete high-resolution topographic map of the entire region. This map was used to generate the image.Two visualization methods were combined to produce the image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the north-south direction. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow, red, and magenta, to white at the highest elevations.For an annotated version of this image, please select Figure 1, below: [figure removed for brevity, see original site] (Large image: 9 mB jpeg)Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on February 11, 2000. The mission used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar that flew twice on the Space Shuttle Endeavour in 1994. The Shuttle Radar Topography Mission was designed to collect

  17. World Globes, Shaded Relief and Colored Height

    Science.gov (United States)

    2003-01-01

    These images of the world were generated with data from the Shuttle Radar Topography Mission (SRTM). The SRTM Project has recently released a new global data set called SRTM30, where the original one arcsecond of latitude and longitude resolution (about 30 meters, or 98 feet, at the equator) was reduced to 30 arcseconds (about 928 meters, or 1496 feet.) These images were created from that data set and show the Earth as it would be viewed from a point in space centered over the Americas, Africa and the western Pacific.Two visualization methods were combined to produce the image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction, so that northwest slopes appear bright and southeast slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations.Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise,Washington, D.C.Orientation: North toward the top Image Data: shaded and colored SRTM elevation model Original Data Resolution: SRTM 1 arcsecond (about 30 meters or 98 feet

  18. Ireland, Shaded Relief and Colored Height

    Science.gov (United States)

    2005-01-01

    The island of Ireland comprises a large central lowland of limestone with a relief of hills surrounded by a discontinuous border of coastal mountains which vary greatly in geological structure. The mountain ridges of the south are composed of old red sandstone separated by limestone river valleys. Granite predominates in the mountains of Galway, Mayo and Donegal in the west and north-west and in Counties Down and Wicklow on the east coast, while a basalt plateau covers much of the north-east of the country. The central plain, which is broken in places by low hills, is extensively covered with glacial deposits of clay and sand. It has considerable areas of bog and numerous lakes. The island has seen at least two general glaciations and everywhere ice-smoothed rock, mountain lakes, glacial valleys and deposits of glacial sand, gravel and clay mark the passage of the ice. Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction, so that northwest slopes appear bright and southeast slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations. Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Geospatial-Intelligence Agency

  19. The influence of apical and basal defoliation on the canopy structure and biochemical composition of Vitis vinifera cv. Shiraz grapes and wine

    Science.gov (United States)

    Zhang, Pangzhen; Wu, Xiwen; Needs, Sonja; Liu, Di; Fuentes, Sigfredo; Howell, Kate

    2017-07-01

    Defoliation is a commonly used viticultural technique to balance the ratio between grapevine vegetation and fruit. Defoliation is conducted around the fruit zone to reduce the leaf photosynthetic area, and to increase sunlight exposure of grape bunches. Apical leaf removal is not commonly practiced, and therefore its influence on canopy structure and resultant wine aroma is not well studied. This study quantified the influences of apical and basal defoliation on canopy structure parameters using canopy cover photography and computer vision algorithms. The influence of canopy structure changes on the chemical compositions of grapes and wines was investigated over two vintages (2010-11 and 2015-16) in Yarra Valley, Australia. The Shiraz grapevines were subjected to five different treatments: no leaf removal (Ctrl); basal (TB) and apical (TD) leaf removal at veraison and intermediate ripeness, respectively. Basal leaf removal significantly reduced the leaf area index and foliage cover and increased canopy porosity, while apical leaf removal had limited influences on canopy parameters. However, the latter tended to result in lower alcohol level in the finished wine. Statistically significant increases in pH and decreases in TA was observed in shaded grapes, while no significant changes in the color profile and volatile compounds of the resultant wine were found. These results suggest that apical leaf removal is an effective method to reduce wine alcohol concentration with minimal influences on wine composition.

  20. Reliability of conventional shade guides in teeth color determination.

    Science.gov (United States)

    Todorović, Ana; Todorović, Aleksandar; Gostović, Aleksandra Spadijer; Lazić, Vojkan; Milicić, Biljana; Djurisić, Slobodan

    2013-10-01

    Color matching in prosthodontic therapy is a very important task because it influences the esthetic value of dental restorations. Visual shade matching represents the most frequently applied method in clinical practice. Instrumental measurements provide objective and quantified data in color assessment of natural teeth and restorations. In instrumental shade analysis, the goal is to achieve the smallest deltaE value possible, indicating the most accurate shade match. The aim of this study was to evaluate the reliability of commercially available ceramic shade guides. VITA Easyshade spectrophotometer (VITA, Germany) was used for instrumental color determination. Utilizing this device, color samples of ten VITA Classical and ten VITA 3D - Master shade guides were analyzed. Each color sample from all shade guides was measured three times and the basic parameters of color quality were examined: deltaL, deltaC, deltaH, deltaE, deltaElc. Based on these parameters spectrophotometer marks the shade matching as good, fair or adjust. After performing 1,248 measurements of ceramic color samples, frequency of evaluations adjust, fair and good were statistically significantly different between VITA Classical and VITA 3D Master shade guides (p = 0.002). There were 27.1% cases scored as adjust, 66.3% as fair and 6.7% as good. In VITA 3D - Master shade guides 30.9% cases were evaluated as adjust, 66.4% as fair and 2.7% cases as good. Color samples from different shade guides, produced by the same manufacturer, show variability in basic color parameters, which once again proves the lack of precision and nonuniformity of the conventional method.

  1. Olduvai Gorge, Shaded Relief and Colored Height

    Science.gov (United States)

    2004-01-01

    Three striking and important areas of Tanzania in eastern Africa are shown in this color-coded shaded relief image from the Shuttle Radar Topography Mission. The largest circular feature in the center right is the caldera, or central crater, of the extinct volcano Ngorongoro. It is surrounded by a number of smaller volcanoes, all associated with the Great Rift Valley, a geologic fault system that extends for about 4,830 kilometers (2,995 miles) from Syria to central Mozambique. Ngorongoro's caldera is 22.5 kilometers (14 miles) across at its widest point and is 610 meters (2,000 feet) deep. Its floor is very level, holding a lake fed by streams running down the caldera wall. It is part of the Ngorongoro Conservation Area and is home to over 75,000 animals. The lakes south of the crater are Lake Eyasi and Lake Manyara, also part of the conservation area. The relatively smooth region in the upper left of the image is the Serengeti National Park, the largest in Tanzania. The park encompasses the main part of the Serengeti ecosystem, supporting the greatest remaining concentration of plains game in Africa including more than 3,000,000 large mammals. The animals roam the park freely and in the spectacular migrations, huge herds of wild animals move to other areas of the park in search of greener grazing grounds (requiring over 4,000 tons of grass each day) and water. The faint, nearly horizontal line near the center of the image is Olduvai Gorge, made famous by the discovery of remains of the earliest humans to exist. Between 1.9 and 1.2 million years ago a salt lake occupied this area, followed by the appearance of fresh water streams and small ponds. Exposed deposits show rich fossil fauna, many hominid remains and items belonging to one of the oldest stone tool technologies, called Olduwan. The time span of the objects recovered dates from 2,100,000 to 15,000 years ago. Two visualization methods were combined to produce the image: shading and color coding of

  2. Discrete Line Congruences for Shading and Lighting

    KAUST Repository

    Wang, Jun

    2013-07-01

    Two-parameter families of straight lines (line congruences) are implicitly present in graphics and geometry processing in several important ways including lighting and shape analysis. In this paper we make them accessible to optimization and geometric computing, by introducing a general discrete version of congruences based on piecewise-linear correspondences between triangle meshes. Our applications of congruences are based on the extraction of a so-called torsion-free support structure, which is a procedure analogous to remeshing a surface along its principal curvature lines. A particular application of such structures are freeform shading and lighting systems for architecture. We combine interactive design of such systems with global optimization in order to satisfy geometric constraints. In this way we explore a new area where architecture can greatly benefit from graphics.

  3. Estimation of canopy water interception of a near-tropical montane cloud forest in Taiwan

    Science.gov (United States)

    Apurva, B.; Huang, C. Y.; Zhang, J.

    2017-12-01

    Tropical and subtropical montane cloud forests are some of the rarest and least studied ecosystems. Due to the frequent immersion of fog water with high humidity, these zones are major water sources for lowland environments and habitats for many fauna and flora. Their dependence on cloud water leaves them highly susceptible to the effects of climate change. Studies have been conducted to quantify the characteristics of the low altitude clouds such as spatial dynamics, cloud top and base heights, occurrence frequency or immersion duration. In this study, we carried out a field measurement to estimate canopy water interception (CWI), which is directly utilized by the ecosystems. The study site was a 61 ha near-tropical hinoki cypress montane cloud forest plantation in northern Taiwan at 1705 m asl. Leaves of CHOB were clipped, air-dried and attached to trees at three different canopy depths from the top to the base of canopies along a high tower. The samples were weighed before and after the occurrence of a fog event. In addition, a cylinder shaped fog gauge was installed at the ground level next to the tower to assess amount of fog water penetrating the canopy layer. After afternoon fog events with the duration of 60 minutes, we found that there was an apparent trend of decline of CWI from top (mean ± standard deviation = 0.023 g ± 0.0015 g), middle (0.021 g ± 0.0015 g) to the bottom (0.013 g ± 0.0015 g) of the canopies. Since the study site is a coniferous evergreen forest plantation with a relatively homogenous surface through seasons, with the background knowledge of the average leaf area index of 4.4, we estimated that this 61 ha site harvested 28.2 Mg of CWI for a daily fog event. We also found that no clear evidence of CWI was observed below the canopies by referring to bi-weekly records from the cylinder shaded fog gauge. Therefore, we can assume that the majority fog water was intercepted by the hinoki cypress canopy layer. This study demonstrates that a

  4. The Influence of Dental Shade Guides and Experience on the Accuracy of Shade Matching.

    Science.gov (United States)

    Nakhaei, Mohammadreza; Ghanbarzadeh, Jalil; Amirinejad, Sahar; Alavi, Samin; Rajatihaghi, Hamidreza

    2016-01-01

    There is limited and inconsistent information on some factors affecting visual shade selection. The aim of this study was to evaluate the influence of shade guide type and professional experience on shade-matching results. Thirty Dental students (DS), 30 General dentists (GDs) and 30 Dental specialists (S) participated in this study. The participants were asked to match six target tabs using two dental shade guides: Vitapan Classical (VC) and Vitapan 3D-Master (3D). An intraoral spectrophotometer was used for color measurement of target tabs and selected tabs. The color difference (ΔE) values between the target tab and selected tab were calculated. Data were analyzed using analysis of variance (ANOVA) and paired f-test (α = 0.05). Results of the first five best matches for each target tab were expressed as ΔE1 to ΔE5. Differences in the mean values of ΔE1 to ΔE5 between VC and 3D were compared using descriptive statistics. There were no significant differences among the three participating groups in ΔE values when the 3D was used (p = 0.389). However, significant differences were found with VC (p Contemp Dent Pract 2016;17(1):22-26. Source of support: This study was supported by a grant (No. 920903) from the Vice Chancellor for Research of Mashhad University of Medical Sciences. The results presented here are based on undergraduate thesis (No. 2686) submitted to Mashhad School of Dentistry and Dental Research Center. None.

  5. An hourly based performance comparison of an integrated micro-structural perforated shading screen with standard shading systems

    DEFF Research Database (Denmark)

    Appelfeld, David; McNeil, Andrew; Svendsen, Svend

    2012-01-01

    This article evaluates the performance of an integrated micro structural perforated shading screen (MSPSS). Such a system maintains a visual connection with the outdoors while imitating the shading functionality of a venetian blind. Building energy consumption is strongly influenced by the solar...... gains and heat transfer through the transparent parts of the fenestration systems. MSPSS is angular-dependent shading device that provides an effective strategy in the control of daylight, solar gains and overheating through windows. The study focuses on using direct experimental methods to determine bi......-directional transmittance properties of shading systems that are not included as standard shading options in readily available building performance simulation tools. The impact on the indoor environment, particularly temperature and daylight were investigated and compared to three other static complex fenestration systems...

  6. An in vitro study to evaluate the difference in shade between commercially available shade guides and glazed porcelain

    Directory of Open Access Journals (Sweden)

    P Manimaran

    2016-01-01

    Full Text Available Introduction: Smile is one of the most important interactive communication skills of a person. A smile is the key factor for an aesthetic appearance. Hence aesthetics is one of the motivating factor for the patients to seek dental care. Correction of unaesthetic appearance gives a positive effect to the self esteem of the patient. Aim: The aim of this study was to compare the difference in the shade between the commercially available shade guides namely Vita Classical And Ivoclar Chromascop and the fired porcelain samples fabricated using Vita Zahnfabrik VMK 95 and Ivoclar Classic Materials respectively. Objectives: The objective of this study was to obtain a matching brand of material that has a particular shade tab among the brands used. Conclusion: To conclude, Ivoclar material matched the chromascop shade guide better than the vita material matched the vita classic shade guide.

  7. An in vitro study to evaluate the difference in shade between commercially available shade guides and glazed porcelain.

    Science.gov (United States)

    Manimaran, P; Sadan, D Sai

    2016-10-01

    Smile is one of the most important interactive communication skills of a person. A smile is the key factor for an aesthetic appearance. Hence aesthetics is one of the motivating factor for the patients to seek dental care. Correction of unaesthetic appearance gives a positive effect to the self esteem of the patient. The aim of this study was to compare the difference in the shade between the commercially available shade guides namely Vita Classical And Ivoclar Chromascop and the fired porcelain samples fabricated using Vita Zahnfabrik VMK 95 and Ivoclar Classic Materials respectively. The objective of this study was to obtain a matching brand of material that has a particular shade tab among the brands used. To conclude, Ivoclar material matched the chromascop shade guide better than the vita material matched the vita classic shade guide.

  8. Heterotrophic respiration in drained tropical peat temperatures influenced by shading gradient

    Science.gov (United States)

    Jauhiainen, Jyrki; Kerojoki, Otto; Silvennoinen, Hanna; Limin, Suwido; Vasander, Harri

    2015-04-01

    Lowland peatlands in Southeast Asia constitute a highly concentrated carbon (C) pool of global significance. These peatlands have formed over periods of several millennia by forest vegetation tolerant to flooding and poor substrates. Uncontrollable drainage and reoccurring wild fires in lack of management after removal of forest cover has impaired the C-storing functions in large reclaimed areas. Intergovernmental Panel on Climate Change (IPCC) reporting sees drained tropical organic soils as one of the largest greenhouse gas emissions releasing terrestrial systems. Vast areas of deforested tropical peatlands do not receive noteworthy shading by vegetation, which increases the amount of solar radiation reaching the peat surface. We studied heterotrophic carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) fluxes in tropical peat in conditions, where; (i) peat temperatures were modified by artificial shading (no shade, 28%, 51% and 90% from the full sun exposure), (ii) root respiration was minimized, (iii) nutrient availability for peat decomposer community was changed (NPK fertilization of 0 and 313 kg ha-1). The experiment was repeated at two over 20 years ago drained fallow agricultural- and degraded sites in Central Kalimantan, Indonesia. Enhanced shading created a lasting decrease in peat temperatures, and decreased diurnal temperature fluctuations, in comparison to less shaded plots. The largest peat temperature difference was between the unshaded and 90% shaded peat surface, where the average temperatures within the topmost 50-cm peat profile differed 3 °C, and diurnal temperatures at 5 cm depth varied up to 4.2 °C in the unshaded and 0.4 °C in the 90% shaded conditions. Highest impacts on the heterotrophic CO2 fluxes caused by the treatments were on agricultural land, where 90% shading from the full exposure resulted in a 33% lower CO2 emission average on the unfertilised plots and a 66% lower emission average on the fertilised plots. Correlation

  9. Photovoltaic Shading Testbed for Module-Level Power Electronics

    Energy Technology Data Exchange (ETDEWEB)

    Deline, C.; Meydbray, J.; Donovan, M.; Forrest, J.

    2012-05-01

    This document describes a repeatable test procedure that attempts to simulate shading situations, as would be experienced by typical residential rooftop photovoltaic (PV) systems. This type of shading test is particularly useful to evaluate the impact of different power conversion setups, including microinverters, DC power optimizers and string inverters, on overall system performance. The performance results are weighted based on annual estimates of shade to predict annual performance improvement. A trial run of the test procedure was conducted with a side by side comparison of a string inverter with a microinverter, both operating on identical 8kW solar arrays. Considering three different shade weighting conditions, the microinverter was found to increase production by 3.7% under light shading, 7.8% under moderate shading, and 12.3% under heavy shading, relative to the reference string inverter case. Detail is provided in this document to allow duplication of the test method at different test installations and for different power electronics devices.

  10. Improved grazing activity of dairy heifers in shaded tropical grasslands

    Directory of Open Access Journals (Sweden)

    Andréia Cristina Tavares de Mello

    Full Text Available ABSTRACT: Trees in the production systems can effectively reduce hot weather-induced stress in the Brazilian Midwest. High temperatures cause changes in animals daily routine, and trees into pastures can promote benefits. The aim of this research was to evaluate the behavior of dairy heifers in silvopastoral systems in the state of Mato Grosso, Brazil. A herd of 24 crossbreed heifers (3/4 and 7/8 Holstein/Zebu, 350kg average weight, was evaluated over three seasons. Piatã grass was managed under three shade levels: full-sun, moderate-shade, and intensive-shade provided by 10 to 12m high Eucalyptus trees. Behavior data were collected every 15 minutes from 8:30h to 16h. Shade availability significantly impacted heifer behavior, mainly affecting grazing frequency and time during the hottest hours. Grazing behavior was affected by shade levels during the different seasons. Heifers showed preferred grazing times. Heifers in the intensive-shade system visited shady areas during the hottest hours throughout the seasons. Heifers in the full sun-system avoided grazing during the warmer times, ceasing feeding activities. Our results from the Brazilian Midwest showed that shade availability causes breed heifers to change their daily routine.

  11. A numerical study to evaluate the effects of a plant canopy on the modification of thermal environment

    International Nuclear Information System (INIS)

    Nakano, Y.; Cho, T.

    1985-01-01

    It is clear that ground conditions have a large effect on the thermal environment. Plant canopies have their own characteristic types of architecture and have a great influence upon the action and reaction processes occurring between plants and their environment through the modification and interception of fluxes of radiation, heat and mass. A numerical experiment was carried out to determine the diurnal changes occurring in soil and air temperatures near the ground surface covered by a plant. The model assumed that a canopy can be mathematically condensed into a single plane and treated as a single ‘big leaf’. The stomatal resistance was estimated by using the rectangular hyperbolic relationship between stomatal resistance and irradiance. Wind velocity, potential temperature and specific humidity values of 3.6m/s, 25°C and 0.0015 were applied respectively at the upper boundary (100 m), and a temperature of 25°C was specified for the lower boundary (-0.5m). All these conditions were kept constant throughout the simulation period. The analysis was performed on the basis of irradiant data obtained in Fukuoka City (latitude 33° 38'N) on 26 th July, 1978. The temperature profiles during daylight were characterized by curves with a maximum in the canopy layer. The temperature range on the soil surface was reduced owing to the effect of shading by the leaves. These phenomena make the formation of the thermal environment on a plant canopy extremely complex. In the case presented in this paper, the type of plant canopy investigated was similar to that of a soybean field with plants 1.00 m high, but the method could easily be adapted to simulate the thermal environment of a tall canopy, such as that in a forest. (author)

  12. Australia, Shaded Relief and Colored Height

    Science.gov (United States)

    2004-01-01

    Australia is the world's smallest, flattest, and (after Antarctica) driest continent, but at 7.7 million square kilometers (3.0 million square miles) it is also the sixth largest country. Its low average elevation (300 meters, or less than 1000 feet) is caused by its position near the center of a tectonic plate, where there are no volcanic or other geologic forces of the type that raise the topography of other continents. In fact Australia is the only continent without any current volcanic activity at all - the last eruption took place 1400 years ago at Mt. Gambier. The Australian continent is also one of the oldest land masses, with some of its erosion-exposed bedrock age dated at more than 3 billion years. More than one-fifth of the land area is desert, with more than two-thirds being classified as arid or semi-arid and unsuitable for settlement. The coldest regions are in the highlands and tablelands of Tasmania and the Australian Alps at the southeastern corner of the continent, location of Australia's highest point, Mt. Kosciusko (2228 meters, or 7310 feet.) Prominent features of Australia include the Lake Eyre basin, the darker green region visible in the center-right. At 16 meters (52 feet) below sea level this depression is one of the largest inland drainage systems in the world, covering more than 1.3 million square kilometers (500,000 square miles). The mountain range near the east coast is called the Great Dividing Range, forming a watershed between east and west flowing rivers. Erosion has created deep valleys, gorges and waterfalls in this range where rivers tumble over escarpments on their way to the sea. The crescent shaped uniform green region in the south, just left of center, is the Nullarbor Plain, a low-lying limestone plateau which is so flat that the Trans-Australian Railway runs through it in a straight line for more than 483 kilometers (300 miles). Two visualization methods were combined to produce this image: shading and color coding of

  13. Guiana Highlands, Shaded Relief and Colored Height

    Science.gov (United States)

    2003-01-01

    Doyle's 1912 best-seller 'The Lost World.'Two visualization methods were combined to produce the image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction, so that northwest slopes appear bright and southeast slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations.Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise,Washington, D.C.Location: 0.2 South to 8.7 degrees North latitude, 60 to 67.9 degrees West longitude Orientation: North toward the top Image Data: shaded and colored SRTM30 and GTOPO30 elevation models Data Resolution: SRTM 30 arcsecond (about 928 meters or 1496 feet) Date Acquired: February 2000 for SRTM

  14. France, Shaded Relief and Colored Height

    Science.gov (United States)

    2003-01-01

    This image of France was generated with data from the Shuttle Radar Topography Mission (SRTM). For this broad view the resolution of the data was reduced to 6 arcseconds (about 185 meters north-south and 127 meters east-west), resampled to a Mercator projection, and the French border outlined. Even at this decreased resolution the variety of landforms comprising the country is readily apparent.The upper central part of this scene is dominated by the Paris Basin, which consists of a layered sequence of sedimentary rocks. Fertile soils over much of the area make good agricultural land. The Normandie coast to the upper left is characterized by high, chalk cliffs, while the Brittany coast (the peninsula to the left) is highly indented where deep valleys were drowned by the sea, and the Biscay coast to the southwest is marked by flat, sandy beaches.To the south, the Pyrenees form a natural border between France and Spain, and the south-central part of the country is dominated by the ancient Massif Central. Subject to volcanism that has only subsided in the last 10,000 years, these central mountains are separated from the Alps by the north-south trending Rhone River Basin.Two visualization methods were combined to produce the image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction, so that northwest slopes appear bright and southeast slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations.Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D

  15. Testing a ground-based canopy model using the wind river canopy crane

    Science.gov (United States)

    Robert Van Pelt; Malcolm P. North

    1999-01-01

    A ground-based canopy model that estimates the volume of occupied space in forest canopies was tested using the Wind River Canopy Crane. A total of 126 trees in a 0.25 ha area were measured from the ground and directly from a gondola suspended from the crane. The trees were located in a low elevation, old-growth forest in the southern Washington Cascades. The ground-...

  16. VitiCanopy: A Free Computer App to Estimate Canopy Vigor and Porosity for Grapevine

    Directory of Open Access Journals (Sweden)

    Roberta De Bei

    2016-04-01

    Full Text Available Leaf area index (LAI and plant area index (PAI are common and important biophysical parameters used to estimate agronomical variables such as canopy growth, light interception and water requirements of plants and trees. LAI can be either measured directly using destructive methods or indirectly using dedicated and expensive instrumentation, both of which require a high level of know-how to operate equipment, handle data and interpret results. Recently, a novel smartphone and tablet PC application, VitiCanopy, has been developed by a group of researchers from the University of Adelaide and the University of Melbourne, to estimate grapevine canopy size (LAI and PAI, canopy porosity, canopy cover and clumping index. VitiCanopy uses the front in-built camera and GPS capabilities of smartphones and tablet PCs to automatically implement image analysis algorithms on upward-looking digital images of canopies and calculates relevant canopy architecture parameters. Results from the use of VitiCanopy on grapevines correlated well with traditional methods to measure/estimate LAI and PAI. Like other indirect methods, VitiCanopy does not distinguish between leaf and non-leaf material but it was demonstrated that the non-leaf material could be extracted from the results, if needed, to increase accuracy. VitiCanopy is an accurate, user-friendly and free alternative to current techniques used by scientists and viticultural practitioners to assess the dynamics of LAI, PAI and canopy architecture in vineyards, and has the potential to be adapted for use on other plants.

  17. Subtle variation in shade avoidance responses may have profound consequences for plant competitiveness.

    Science.gov (United States)

    Bongers, Franca J; Pierik, Ronald; Anten, Niels P R; Evers, Jochem B

    2017-12-21

    Although phenotypic plasticity has been shown to be beneficial for plant competitiveness for light, there is limited knowledge on how variation in these plastic responses plays a role in determining competitiveness. A combination of detailed plant experiments and functional-structural plant (FSP) modelling was used that captures the complex dynamic feedback between the changing plant phenotype and the within-canopy light environment in time and 3-D space. Leaf angle increase (hyponasty) and changes in petiole elongation rates in response to changes in the ratio between red and far-red light, two important shade avoidance responses in Arabidopsis thaliana growing in dense population stands, were chosen as a case study for plant plasticity. Measuring and implementing these responses into an FSP model allowed simulation of plant phenotype as an emergent property of the underlying growth and response mechanisms. Both the experimental and model results showed that substantial differences in competitiveness may arise between genotypes with only marginally different hyponasty or petiole elongation responses, due to the amplification of plant growth differences by small changes in plant phenotype. In addition, this study illustrated that strong competitive responses do not necessarily have to result in a tragedy of the commons; success in competition at the expense of community performance. Together, these findings indicate that selection pressure could probably have played a role in fine-tuning the sensitive shade avoidance responses found in plants. The model approach presented here provides a novel tool to analyse further how natural selection could have acted on the evolution of plastic responses.

  18. Bone Canopies in Pediatric Renal Osteodystrophy

    DEFF Research Database (Denmark)

    Pereira, Renata C; Levin Andersen, Thomas; Friedman, Peter A

    2016-01-01

    Pediatric renal osteodystrophy (ROD) is characterized by changes in bone turnover, mineralization, and volume that are brought about by alterations in bone resorption and formation. The resorptive and formative surfaces on the cancellous bone are separated from the marrow cavity by canopies...... and their association with biochemical and bone histomorphometric parameters in 106 pediatric chronic kidney disease (CKD) patients (stage 2-5) across the spectrum of ROD. Canopies in CKD patients often appeared as thickened multilayered canopies, similar to previous reports in patients with primary hyperparathyroidism....... This finding contrasts with the thin appearance reported in healthy individuals with normal kidney function. Furthermore, canopies in pediatric CKD patients showed immunoreactivity to the PTH receptor (PTHR1) as well as to the receptor activator of nuclear factor kappa-B ligand (RANKL). The number of surfaces...

  19. Drought tolerance of tropical tree species : functional traits, trade-offs and species distribution

    NARCIS (Netherlands)

    Markesteijn, L.

    2010-01-01

    KEY-WORDS:
    Bolivia, drought tolerance, shade tolerance, functional traits, trade-offs, ecophysiology, species distribution
    Tropical forests occur under rainfall regimes that vary greatly in the rainfall pattern and frequency and intensity of drought. Consequently water availability is

  20. Freezing tolerance and the histology of recovering nodes in St. Augustinegrass

    Science.gov (United States)

    St. Augustinegrass [Stenataphrum secundatum (Walt.) Kuntze] is a coarse-textured turfgrass commonly utilized for its excellent shade tolerance. However, inferior cold tolerance in comparison to other warm-season grasses limits its range primarily to the southeastern U. S., The objectives of this stu...

  1. Uptake of small particles by tree canopies

    International Nuclear Information System (INIS)

    Belot, Y.; Camus, H.; Gauthier, D.; Caput, C.

    1992-01-01

    Most of the deposition data that are available to assess the radiological consequences of an accident have been acquired for low-growing vegetation and are inadapted to forest areas. Consequently, a programme was undertaken to study the deposition of particles on components of different trees and extrapolate the experimental data so obtained to large-scale canopies. The experiments were performed in a wind tunnel allowing canopy components to be exposed to a flow of suspended fluorescent particles of reasonably uniform size. Emphasis was put on particles in the 0.3-1.2 μm subrange, because most of the radioactive particles sampled at long distance from sources are comprised in this size interval. The uptake rates were determined for bare and leaf bearing twigs of several evergreen species (Picea abies, Pinus sylvestris and Quercus ilex), as a function of wind speed and particle size. The deposition rates obtained for the tree components were then used as input to a model that describes the uptake of particles by a large-scale canopy under specified conditions of weather and canopy structure. The model accounts for the diffusion of particles between different strata of the canopy, as well as deposition of particles on the canopy components. It calculates the rates of particle deposition to the horizontal surface of the canopy, and the repartition of the deposited particles within the canopy. Increases in wind speed cause increased deposition, but the effect is less important that it would have been for larger particles. The deposition is relatively insensitive to the size of particles within the subrange considered in this study. 13 refs., 2 figs., 1 tab

  2. Properly placed shade trees reduce summertime electricity bills in Sacramento, California

    Science.gov (United States)

    Geoffery H. Donovan; David R. Butry

    2009-01-01

    The discovery that shade trees can reduce home cooling costs is hardly surprising. Anybody who has sat under a tree on a warm summer day understands the shade benefit of trees. However, quantifying the effect a shade tree has on home energy use and carbon footprint, and identifying the optimal location for a shade tree, is less straightforward. Past studies that have...

  3. The Importance of Representing Certain Key Vegetation Canopy Processes Explicitly in a Land Surface Model

    Science.gov (United States)

    Napoly, A.; Boone, A. A.; Martin, E.; Samuelsson, P.

    2015-12-01

    Land surface models are moving to more detailed vegetation canopy descriptions in order to better represent certain key processes, such as Carbon dynamics and snowpack evolution. Since such models are usually applied within coupled numerical weather prediction or spatially distributed hydrological models, these improvements must strike a balance between computational cost and complexity. The consequences of simplified or composite canopy approaches can be manifested in terms of increased errors with respect to soil temperatures, estimates of the diurnal cycle of the turbulent fluxes or snow canopy interception and melt. Vegetated areas and particularly forests are modeled in a quite simplified manner in the ISBA land surface model. However, continuous developments of surface processes now require a more accurate description of the canopy. A new version of the the model now includes a multi energy balance (MEB) option to explicitly represent the canopy and the forest floor. It will be shown that certain newly included processes such as the shading effect of the vegetation, the explicit heat capacity of the canopy, and the insulating effect of the forest floor turn out to be essential. A detailed study has been done for four French forested sites. It was found that the MEB option significantly improves the ground heat flux (RMSE decrease from 50W/m2 to 10W/m2 on average) and soil temperatures when compared against measurements. Also the sensible heat flux calculation was improved primarily owing to a better phasing with the solar insulation owing to a lower vegetation heat capacity. However, the total latent heat flux is less modified compared to the classical ISBA simulation since it is more related to water uptake and the formulation of the stomatal resistance (which are unchanged). Next, a benchmark over 40 Fluxnet sites (116 cumulated years) was performed and compared with results from the default composite soil-vegetation version of ISBA. The results show

  4. Reduction in photosynthetic efficiency of Cladophora glomerata, induced by overlying canopies of Lemna spp.

    Science.gov (United States)

    Parr, L B; Perkins, R G; Mason, C F

    2002-04-01

    The duckweeds Lemna minor L. and L. minuscula Herter reduced PSII quantum efficiency (F'q/F'm) of the filamentous green alga Cladophora glomerata Kützing by up to 42% over seven days when floating above mats of C. glomerata in containers. Dissolved oxygen (DO) increased by 23% at 30 degrees C in containers with C. glomerata over controls. But when the water surface in the containers was covered with Lemna spp. floating above C. glomerata, DO was 83% lower at 30 degrees C over seven days than in control samples with no duckweed or alga. Dissolved oxygen was lower beneath a thick mat (1 cm) of either Lemna spp. covering the surface than under a thin layer (single-frond canopy). PAM fluorimetry showed that maximum PSII efficiency (Fv/Fm) of C. glomerata in containers was reduced under a canopy of L. minor by 17% over seven days, and under L. minuscula by 22%. F'q/F'm of C. glomerata in containers exposed to 51 micromol m(-2) s(-1) PPFD decreased under a canopy of L. minor by 16% over seven days, and under L. minuscula by 19% compared to controls. When light response curves were compared, F'q/F'm was significantly reduced under canopies of L. minor at the highest temperatures tested (28 degrees C and 30 degrees C). L. minor significantly reduced relative electron transport rate (rel. ETR) of the controls by up to 71% at 30 degrees C. Relative electron transport rate did not reach light saturation point (Esat) except at 28 degrees and 30 degrees C under mats of L. minor. Whereas the highest rate of production (rel. ETRmax) and Esat increased with temperature in controls, under a canopy of Lemna, decreases were observed. It is suggested that, during periods of high summer temperature and irradiance, shading inhibits oxygenic photosynthesis in mats of C. glomerata beneath canopies of Lenma spp. This results in less oxygen being produced by the C. glomerata (oxygen produced by Lemna spp. is not released into the water), and this may further inhibit the C. glomerata by

  5. On the Impact of Partial Shading on PV Output Power

    DEFF Research Database (Denmark)

    Sera, Dezso; Baghzouz, Yahia

    2008-01-01

    clarifies the mechanism of partial PV shading on a number of PV cells connected in series and/or parallel with and without bypass diodes. The analysis is presented in simple terms and can be useful to someone who wishes to determine the impact of some shading geometry on a PV system. The analysis...... is illustrated by measurements on a commercial 70 W panel, and a 14.4 kW PV array....

  6. Analysis of the internal shading in a photovoltaic greenhouse tunnel

    Directory of Open Access Journals (Sweden)

    Alvaro Marucci

    2017-09-01

    Full Text Available In recent years, the increasing interest in energy production from renewable energy sources has led to photovoltaic elements being placed on greenhouse coverings. The shading of crops by these elements can, however, cause problems regarding the normal course of agricultural activity. All studies thus far on the application of photovoltaic (PV panels as a greenhouse covering material have focused on flat roof structures. Tunnel greenhouses, due to their curved shape, do not lend themselves easily to accommodating PV panels on even part of the cover. In this study, we analysed the shading variation inside a tunnel greenhouse that was produced by applying flexible and transparent PV panels in a checkerboard arrangement. The transparent flexible PV panels are manufactured using monocrystalline silicon cells, with an efficiency of 18%, incorporated into polymers with high resistance. The PV panel dimensions are 1.116×0.165 m. The simulation software Autodesk® Autocad2010® was used for this study. The variation and distribution of the shading percentage of PV panels were analysed in relation to the surface area affected by the photovoltaic roof, the total area of the greenhouse and the section of the greenhouse. In particular, we studied the variations in the percentage of shading and the size of the shaded area on the twenty-first day of each month of the year. The results show some regularity in the shading percentage, mainly due to the curvilinear shape of the section of the greenhouse. From mid-March to mid- September, the shading in the middle of the day is almost always inside the greenhouse. In the other months of the year, it is partly inside and partly outside the tunnel greenhouse. With the photovoltaic arrangement adopted, the percentage of shading during the year never exceeds 40%.

  7. A Technique Using Calibrated Photography and Photoshop for Accurate Shade Analysis and Communication.

    Science.gov (United States)

    McLaren, Edward A; Figueira, Johan; Goldstein, Ronald E

    2017-02-01

    This article reviews the critical aspects of controlling the shade-taking environment and discusses various modalities introduced throughout the years to acquire and communicate shade information. Demonstrating a highly calibrated digital photographic technique for capturing shade information, this article shows how to use Photoshop® to standardize images and extract color information from the tooth and shade tab for use by a ceramist for an accurate shade-matching restoration.

  8. Effects of chronic elevated ozone exposure on gas exchange responses of adult beech trees (Fagus sylvatica) as related to the within-canopy light gradient

    International Nuclear Information System (INIS)

    Kitao, Mitsutoshi; Loew, Markus; Heerdt, Christian; Grams, Thorsten E.E.; Haeberle, Karl-Heinz; Matyssek, Rainer

    2009-01-01

    The effects of elevated O 3 on photosynthetic properties in adult beech trees (Fagus sylvatica) were investigated in relation to leaf mass per area as a measure of the gradually changing, within-canopy light availability. Leaves under elevated O 3 showed decreased stomatal conductance at unchanged carboxylation capacity of Rubisco, which was consistent with enhanced δ 13 C of leaf organic matter, regardless of the light environment during growth. In parallel, increased energy demand for O 3 detoxification and repair was suggested under elevated O 3 owing to enhanced dark respiration. Only in shade-grown leaves, light-limited photosynthesis was reduced under elevated O 3 , this effect being accompanied by lowered F v /F m . These results suggest that chronic O 3 exposure primarily caused stomatal closure to adult beech trees in the field regardless of the within-canopy light gradient. However, light limitation apparently raised the O 3 sensitivity of photosynthesis and accelerated senescence in shade leaves. - Across leaf differentiation in adult beech crowns, elevated ozone acted through stomatal closure on gas exchange although enhancing photosynthetic sensitivity of shaded leaves

  9. Shade treatment affects structure and recovery of invasive C4 African grass Echinochloa pyramidalis.

    Science.gov (United States)

    López Rosas, Hugo; Moreno-Casasola, Patricia; Espejel González, Verónica E

    2015-03-01

    Echinochloa pyramidalis (Lam.) Hitchc. & Chase is an African grass with C4 photosynthesis, high biomass production, and high vegetative propagation that is tolerant to grazing and able to grow in flooded and dry conditions. Thus, it is highly invasive in tropical freshwater marshes where it is intentionally planted by ranchers to increase cattle production. This invasion is reducing plant biodiversity by increasing the invader's aerial coverage, changing wetland hydrology and causing soil physicochemical changes such as vertical accretion. Reducing the dominance of this species and increasing the density of native wetland species is a difficult, expensive, and time-consuming process. We applied a series of disturbance treatments aimed at eliminating E. pyramidalis and recovering the native vegetation of a partially invaded freshwater marsh. Treatments included physical (cutting, soil disking, transplanting individuals of the key native species Sagittaria lancifolia subsp. media (Micheli) Bogin, and/or reducing light with shade mesh) and/or chemical (spraying Round-Up™ herbicide) disturbances. At the end of the experiment, four of the five treatments used were effective in increasing the cover and biomass of native species and reducing that of E. pyramidalis. The combination of these treatments should be used to generate a proposal for the restoration of tropical wetlands invaded by non-native grasses. A promising treatment is using soil disked to soften the soil and destroy belowground structures such as roots and rhizomes. This treatment would be more promising if combined with the use of shade cloth. If it is desirable not to impact the soil or if there is not enough budget to make an effort to include active restoration disking soil, the use of shade cloth will suffice, although the recovery of native vegetation will be slower.

  10. Ecosystem Service of Shade Trees on Nutrient Cycling and Productivity of Coffee Agro-ecosystems

    Directory of Open Access Journals (Sweden)

    Rusdi Evizal

    2009-05-01

    Full Text Available Shade trees are significant in certification scheme of sustainable coffee production. They play an importance role on ecosystem functioning. This research is aimed to study ecosystem service of shade trees in some coffee agro-ecosystems particularly on nutrient cycling and land productivity. Four agro-ecosys tems of Robusta coffee (Coffea canephora, namely sun coffee (without shade trees, coffee shaded by Michelia champaca, coffee shaded by Gliricidia sepium, and coffee shaded by Erythrina indica are evaluated during 2007—2008. Smallholder coffee plantation in Sumberjaya Subdistrict, West Lampung, which managed under local standard were employed using Randomized Complete Block Design with 3 replications. The result showed that litter fall dynamic from shade trees and from coffee trees was influenced by rainfall. Shade trees decreased weed biomass while increased litter fall production. In dry season, shade trees decreased litter fall from coffee shaded by M. champaca. G. sepium and E. indica shaded coffee showed higher yield than sun coffee and M. champaca shaded coffee. Except for M. champaca shaded coffee, yield had positive correlation (r = 0.99 with litter fall production and had negative correlation (r = —0.82 with weed biomass production. Biomass production (litter fall + weed of sun coffee and shaded coffee was not significantly different. Litter fall of shade trees had significance on nutrient cycle mainly to balance the lost of nitrogen in coffee bean harvesting.Key Words: Coffea canephora, Michelia champaca, Gliricidia sepium, Erythrina indica, litter production, nutrient cycle, coffee yield.

  11. Shaded relief, color as height, Fiji

    Science.gov (United States)

    2000-01-01

    The Sovereign Democratic Republic of the Fiji Islands, commonly known as Fiji, is an independent nation consisting of some 332 islands surrounding the Koro Sea in the South Pacific Ocean. This topographic image shows Viti Levu, the largest island in the group. With an area of 10,429 square kilometers (about 4000 square miles), it comprises more than half the area of the Fiji Islands. Suva, the capital city, lies on the southeast shore. The Nakauvadra, the rugged mountain range running from north to south, has several peaks rising above 900 meters (about 3000 feet). Mount Tomanivi, in the upper center, is the highest peak at 1324 meters (4341 feet). The distinct circular feature on the north shore is the Tavua Caldera, the remnant of a large shield volcano that was active about 4 million years ago. Gold has been mined on the margin of the caldera since the 1930's. The Nadrau plateau is the low relief highland in the center of the mountain range. The coastal plains in the west, northwest and southeast account for only 15 percent of Viti Levu's area but are the main centers of agriculture and settlement.This shaded relief image was generated using topographic data from the Shuttle Radar Topography Mission. A computer-generated artificial light source illuminates the elevation data to produce a pattern of light and shadows. Slopes facing the light appear bright, while those facing away are shaded. On flatter surfaces, the pattern of light and shadows can reveal subtle features in the terrain. Colors show the elevation as measured by SRTM. Colors range from green at the lowest elevations top ink at the highest elevations. This image contains about 1300 meters(4300 feet) of total relief.The Shuttle Radar Topography Mission (SRTM), launched on February 11,2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect

  12. Las notas al pie en la traducción de Fifty Shades (Footnotes in the Translation of Fifty Shades

    Directory of Open Access Journals (Sweden)

    Xinia Valverde Jara

    2017-11-01

    Full Text Available Se analiza el recurso de las notas a pie de página insertas en la traducción independiente de literatura comercial en versión digital, de la trilogía Fifty Shades of Grey, Fifty Shades Darker y Fifty Shades Freed, de E. L. James. Se examina el grado de influencia de esos elementos extratextuales, y se concluye que todos ellos, organizados en un complejo proceso de traducción, en especial los del contexto de llegada, condicionan la estrategia traductológica. Abstract This study examines the use of footnotes as a translation strategy in the independent translation of commercial literature in digital format, based on the trilogy written by E. L. James, Fifty Shades of Grey, Fifty Shades Darker and Fifty Shades Freed. The analysis measures the influence of these extratextual elements within the complex translation process, specifically those of the target language context, and it is concluded that they condition the translation strategies used.

  13. Remote sensing of sagebrush canopy nitrogen

    Science.gov (United States)

    Mitchell, Jessica J.; Glenn, Nancy F.; Sankey, Temuulen T.; Derryberry, DeWayne R.; Germino, Matthew J.

    2012-01-01

    This paper presents a combination of techniques suitable for remotely sensing foliar Nitrogen (N) in semiarid shrublands – a capability that would significantly improve our limited understanding of vegetation functionality in dryland ecosystems. The ability to estimate foliar N distributions across arid and semi-arid environments could help answer process-driven questions related to topics such as controls on canopy photosynthesis, the influence of N on carbon cycling behavior, nutrient pulse dynamics, and post-fire recovery. Our study determined that further exploration into estimating sagebrush canopy N concentrations from an airborne platform is warranted, despite remote sensing challenges inherent to open canopy systems. Hyperspectral data transformed using standard derivative analysis were capable of quantifying sagebrush canopy N concentrations using partial least squares (PLS) regression with an R2 value of 0.72 and an R2 predicted value of 0.42 (n = 35). Subsetting the dataset to minimize the influence of bare ground (n = 19) increased R2 to 0.95 (R2 predicted = 0.56). Ground-based estimates of canopy N using leaf mass per unit area measurements (LMA) yielded consistently better model fits than ground-based estimates of canopy N using cover and height measurements. The LMA approach is likely a method that could be extended to other semiarid shrublands. Overall, the results of this study are encouraging for future landscape scale N estimates and represent an important step in addressing the confounding influence of bare ground, which we found to be a major influence on predictions of sagebrush canopy N from an airborne platform.

  14. South America, Shaded Relief and Colored Height

    Science.gov (United States)

    2003-01-01

    occurrence of simple erosional processes acting upon fairly uniform bedrock. Very smooth plateaus here are remnants of landforms most likely developed under geologic and environmental conditions much different than those present today. Fractures paralleling the coast are likely related to the opening of the Atlantic Ocean as South America drifted away from Africa, starting about 130 million years ago.To the southwest, broad lowlands host the Gran Chaco and Pampas regions. The depositional Gran Chaco drainages run almost exclusively from west to east from the Andes Mountains to the western edge of the Brazilian Highlands as a result of the much greater sediment supply from the Andes. Geologic processes on the Pampas are much more diverse, with stream erosion, stream deposition, subsidence, and wind processes all evident, even at the one-kilometer resolution shown here.Further south, Patagonia also displays these geologic processes plus more prominent volcanic features, including bumpy mesas, which are lava plateaus with small (and some large) volcanic cones. At its southern tip South America breaks into islands that include Tierra del Fuego and the Straits of Magellan.Two visualization methods were combined to produce the image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction, so that northwest slopes appear bright and southeast slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations.Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of

  15. Scaling up stomatal conductance from leaf to canopy using a dual-leaf model for estimating crop evapotranspiration.

    Directory of Open Access Journals (Sweden)

    Risheng Ding

    Full Text Available The dual-source Shuttleworth-Wallace model has been widely used to estimate and partition crop evapotranspiration (λET. Canopy stomatal conductance (Gsc, an essential parameter of the model, is often calculated by scaling up leaf stomatal conductance, considering the canopy as one single leaf in a so-called "big-leaf" model. However, Gsc can be overestimated or underestimated depending on leaf area index level in the big-leaf model, due to a non-linear stomatal response to light. A dual-leaf model, scaling up Gsc from leaf to canopy, was developed in this study. The non-linear stomata-light relationship was incorporated by dividing the canopy into sunlit and shaded fractions and calculating each fraction separately according to absorbed irradiances. The model includes: (1 the absorbed irradiance, determined by separately integrating the sunlit and shaded leaves with consideration of both beam and diffuse radiation; (2 leaf area for the sunlit and shaded fractions; and (3 a leaf conductance model that accounts for the response of stomata to PAR, vapor pressure deficit and available soil water. In contrast to the significant errors of Gsc in the big-leaf model, the predicted Gsc using the dual-leaf model had a high degree of data-model agreement; the slope of the linear regression between daytime predictions and measurements was 1.01 (R2 = 0.98, with RMSE of 0.6120 mm s-1 for four clear-sky days in different growth stages. The estimates of half-hourly λET using the dual-source dual-leaf model (DSDL agreed well with measurements and the error was within 5% during two growing seasons of maize with differing hydrometeorological and management strategies. Moreover, the estimates of soil evaporation using the DSDL model closely matched actual measurements. Our results indicate that the DSDL model can produce more accurate estimation of Gsc and λET, compared to the big-leaf model, and thus is an effective alternative approach for estimating and

  16. Simplified Method for Modeling the Impact of Arbitrary Partial Shading Conditions on PV Array Performance: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    MacAlpine, Sara; Deline, Chris

    2015-09-15

    It is often difficult to model the effects of partial shading conditions on PV array performance, as shade losses are nonlinear and depend heavily on a system's particular configuration. This work describes and implements a simple method for modeling shade loss: a database of shade impact results (loss percentages), generated using a validated, detailed simulation tool and encompassing a wide variety of shading scenarios. The database is intended to predict shading losses in crystalline silicon PV arrays and is accessed using basic inputs generally available in any PV simulation tool. Performance predictions using the database are within 1-2% of measured data for several partially shaded PV systems, and within 1% of those predicted by the full, detailed simulation tool on an annual basis. The shade loss database shows potential to considerably improve performance prediction for partially shaded PV systems.

  17. The effect of various disinfectants on dental shade guides.

    Science.gov (United States)

    Huang, Peterson Y; Masri, Radi; Romberg, Elaine; Driscoll, Carl F

    2014-09-01

    Dental shade guides are used to evaluate tooth color before prosthodontic procedures and are subjected to disinfection after use. The effect of disinfection on shade guides has not been thoroughly investigated. The purpose of this study was to evaluate the effect of disinfectants on the color of shade tabs. Changes in the color (ΔE) of VITA Classical Shade Guide tabs were measured with a VITA Easyshade spectrophotometer in the CIELAB system and calculated after being subjected to Cavicide, Asepticare TB, Sporicidin, and distilled water (control) over a simulated period of 2 years. Statistical analysis was accomplished by a 2-way analysis of variance followed by the Tukey honestly significant difference (HSD) test (α=.05). A significant difference was noted in the degree of shade tab color change, depending on the type of disinfectant used (F=153.2, PCavicide (ΔE=1.198). The average total CIELAB color difference for 50% human perceptibility is approximately 1 unit (under standardized laboratory conditions). In the oral cavity, however, an average change of 3.7 ΔE units could still allow teeth to be perceived as having the same color. Therefore, although the results are statistically significant, they may not be clinically important. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  18. Nondestructive, stereological estimation of canopy surface area

    DEFF Research Database (Denmark)

    Wulfsohn, Dvora-Laio; Sciortino, Marco; Aaslyng, Jesper M.

    2010-01-01

    We describe a stereological procedure to estimate the total leaf surface area of a plant canopy in vivo, and address the problem of how to predict the variance of the corresponding estimator. The procedure involves three nested systematic uniform random sampling stages: (i) selection of plants from...... a canopy using the smooth fractionator, (ii) sampling of leaves from the selected plants using the fractionator, and (iii) area estimation of the sampled leaves using point counting. We apply this procedure to estimate the total area of a chrysanthemum (Chrysanthemum morifolium L.) canopy and evaluate both...... the time required and the precision of the estimator. Furthermore, we compare the precision of point counting for three different grid intensities with that of several standard leaf area measurement techniques. Results showed that the precision of the plant leaf area estimator based on point counting...

  19. BOREAS TE-9 NSA Canopy Biochemistry

    Science.gov (United States)

    Hall, Forrest G. (Editor); Curd, Shelaine (Editor); Margolis, Hank; Charest, Martin; Sy, Mikailou

    2000-01-01

    The BOREAS TE-9 team collected several data sets related to chemical and photosynthetic properties of leaves. This data set contains canopy biochemistry data collected in 1994 in the NSA at the YJP, OJR, OBS, UBS, and OA sites, including biochemistry lignin, nitrogen, cellulose, starch, and fiber concentrations. These data were collected to study the spatial and temporal changes in the canopy biochemistry of boreal forest cover types and how a high-resolution radiative transfer model in the mid-infrared could be applied in an effort to obtain better estimates of canopy biochemical properties using remote sensing. The data are available in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  20. INITIAL DEVELOPMENT OF AÇAÍ PLANTS UNDER SHADE GRADATION

    Directory of Open Access Journals (Sweden)

    ELEANDRO CANDIDO DAPONT

    2016-01-01

    Full Text Available ABSTRACT In order to evaluate the effect of different levels of shading on açai (Euterpe oleracea Mart. plants development, an experiment was conducted at the nursery of Floresta, Rio Branco, AC. The experiment was arranged in a completely randomized design with six treatments and four replications of 25 plants, set as full sunlight and 18%, 35%, 50%, 70%, and 80% shading. The evaluation occurred 125 days after transplantation and the variables were stem diameter, root length, length of the aerial part, total length, dry matter of root, dry matter of aerial part, and total dry matter. With exception of root length, there was significant difference between treatments for all variables. The production of açai plants should be performed using 40% shading.

  1. Why Shade Coffee Does Not Guarantee Biodiversity Conservation.

    Directory of Open Access Journals (Sweden)

    César Tejeda-Cruz

    2010-03-01

    Full Text Available Over the past decade, various strategies have emerged to address critical habitat losses through agricultural expansion. The promotion of shade-grown, premium-priced coffee has been highlighted as one alternative. Our research, based on interviews with farmers in Chiapas, disputes some of the assumptions made by shade coffee campaigners. Results revealed a predisposition to converting forest to shade coffee production due to the socioeconomic challenges farmers face and the potential for increasing incomes. To ensure that their well-being is improved at the same time as reducing environmental impacts, there is clearly a need to provide more detailed information on who is responsible for enforcing certification criteria and how this should take place.

  2. Wireless sensor networks for canopy temperature sensing and irrigation management

    Science.gov (United States)

    For researchers, canopy temperature measurements have proven useful in characterizing crop water stress and developing protocols for irrigation management. Today, there is heightened interest in using remote canopy temperature measurements for real-time irrigation scheduling. However, without the us...

  3. West Coast Canopy-Forming Kelp, 1989-2014

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — These data include the general extents of canopy-forming kelp surveys from 1989 to 2014 and a compilation of existing data sets delineating canopy-forming kelp beds...

  4. ASSESSING THE CANOPY INTEGRITY USING CANOPY DIGITAL IMAGES IN SEMIDECIDUOUS FOREST FRAGMENT IN SÃO CARLOS - SP- BRAZIL1

    Directory of Open Access Journals (Sweden)

    Thiago Yamada

    2017-11-01

    Full Text Available ABSTRACT It is well-known that conducting experimental research aiming the characterization of canopy structure of forests can be a difficult and costly task and, generally, requires an expert to extract, in loco, relevant information. Aiming at easing studies related to canopy structures, several techniques have been proposed in the literature and, among them, various are based on canopy digital image analysis. The research work described in this paper empirically compares two techniques that measure the integrity of the canopy structure of a forest fragment; one of them is based on central parts of canopy cover images and, the other, on canopy closure images. For the experiments, 22 central parts of canopy cover images and 22 canopy closure images were used. The images were captured along two transects: T1 (located in the conserved area and T2 (located in the naturally disturbance area. The canopy digital images were computationally processed and analyzed using the MATLAB platform for the canopy cover images and the Gap Light Analyzer (GLA, for the canopy closure images. The results obtained using these two techniques showed that canopy cover images and, among the employed algorithms, the Jseg, characterize the canopy integrity best. It is worth mentioning that part of the analysis can be automatically conducted, as a quick and precise process, with low material costs involved.

  5. Estimating biophysical properties of coffee (Coffea canephora) plants with above-canopy field measurements, using CropSpec®

    Science.gov (United States)

    Putra, Bayu T. Widjaja; Soni, Peeyush; Morimoto, Eiji; Pujiyanto, Pujiyanto

    2018-04-01

    Remote sensing technologies have been applied to many crops, but tree crops like Robusta coffee (Coffea canephora) under shade conditions require additional attention while making above-canopy measurements. The objective of this study was to determine how well chlorophyll and nitrogen status of Robusta coffee plants can be estimated with the laser-based (CropSpec®) active sensor. This study also identified appropriate vegetation indices for estimating Nitrogen content by above-canopy measurement, using near-infra red and red-edge bands. Varying light intensity and different background of the plants were considered in developing the indices. Field experiments were conducted involving different non-destructive tools (CropSpec® and SPAD-502 chlorophyll meter). Subsequently, Kjeldahl laboratory analyses were performed to determine the actual Nitrogen content of the plants with different ages and field conditions used in the non-destructive previous stage. Measurements were undertaken for assessing the biophysical properties of tree plant. The usefulness of near-infrared and red-edge bands from these sensors in measuring critical nitrogen levels of coffee plants by above-canopy measurement are investigated in this study.

  6. Optimising building net energy demand with dynamic BIPV shading

    International Nuclear Information System (INIS)

    Jayathissa, P.; Luzzatto, M.; Schmidli, J.; Hofer, J.; Nagy, Z.; Schlueter, A.

    2017-01-01

    Highlights: •Coupled analysis of PV generation and building energy using adaptive BIPV shading. •20–80% net energy saving compared to an equivalent static system. •The system can in some cases compensate for the entire heating/cooling/lighting load. •High resolution radiation simulation including impacts of module self shading. -- Abstract: The utilisation of a dynamic photovoltaic system for adaptive shading can improve building energy performance by controlling solar heat gains and natural lighting, while simultaneously generating electricity on site. This paper firstly presents an integrated simulation framework to couple photovoltaic electricity generation to building energy savings through adaptive shading. A high-resolution radiance and photovoltaic model calculates the photovoltaic electricity yield while taking into account partial shading between modules. The remaining solar irradiation that penetrates the window is used in a resistance-capacitance building thermal model. A simulation of all possible dynamic configurations is conducted for each hourly time step, of which the most energy efficient configuration is chosen. We then utilise this framework to determine the optimal orientation of the photovoltaic panels to maximise the electricity generation while minimising the building’s heating, lighting and cooling demand. An existing adaptive photovoltaic facade was used as a case study for evaluation. Our results report a 20–80% net energy saving compared to an equivalent static photovoltaic shading system depending on the efficiency of the heating and cooling system. In some cases the Adaptive Solar Facade can almost compensate for the entire energy demand of the office space behind it. The control of photovoltaic production on the facade, simultaneously with the building energy demand, opens up new methods of building management as the facade can control both the production and consumption of electricity.

  7. Shading Performance on Terraced House Facades in Putrajaya, Malaysia

    Directory of Open Access Journals (Sweden)

    Hassan Ahmad Sanusi

    2015-01-01

    Full Text Available This study evaluates shading performance on house facades of selected three terraced houses in Putrajaya, Malaysia as the case studies. Terraced house type is selected for the case study because it is the most popular house type built in this country to house an increase of the urban population. Its total number built in urban area increases from 27% of the total dwellings in 1980 to 40% in 1990, and to slightly more than 60 per cent in 2000. The Case Study A, B, and C are atypical style of terraced house facade designs built in Putrajaya. These postmodern designs exhibit a range of complex geometric elements blending of colonial and traditional elements with colorful styles on the house facade. In this study, the time at which the sun path perpendicular to the house facade will be used to gain the results of shading performances when the house facades have their maximum exposure to the direct sunlight. The house facade was divided into two main parts which are opaque and glazing surface elements. The amount of shading area on the opaque and glazing surface was simulated using the SunTool program. In conclusion, the Case Study C had the highest average percentage of the shading area, which is 64.43%, followed by the Case Study A 60.41% and Case Study B 56.29%. These results showed that the facade designs had excellent horizontal shading elements with roof overhangs for high angle sunlight but they had weak vertical shading elements due to a lack of considerations of louvered elements to block low angle sunlight.

  8. Iterative CT shading correction with no prior information

    Science.gov (United States)

    Wu, Pengwei; Sun, Xiaonan; Hu, Hongjie; Mao, Tingyu; Zhao, Wei; Sheng, Ke; Cheung, Alice A.; Niu, Tianye

    2015-11-01

    Shading artifacts in CT images are caused by scatter contamination, beam-hardening effect and other non-ideal imaging conditions. The purpose of this study is to propose a novel and general correction framework to eliminate low-frequency shading artifacts in CT images (e.g. cone-beam CT, low-kVp CT) without relying on prior information. The method is based on the general knowledge of the relatively uniform CT number distribution in one tissue component. The CT image is first segmented to construct a template image where each structure is filled with the same CT number of a specific tissue type. Then, by subtracting the ideal template from the CT image, the residual image from various error sources are generated. Since forward projection is an integration process, non-continuous shading artifacts in the image become continuous signals in a line integral. Thus, the residual image is forward projected and its line integral is low-pass filtered in order to estimate the error that causes shading artifacts. A compensation map is reconstructed from the filtered line integral error using a standard FDK algorithm and added back to the original image for shading correction. As the segmented image does not accurately depict a shaded CT image, the proposed scheme is iterated until the variation of the residual image is minimized. The proposed method is evaluated using cone-beam CT images of a Catphan©600 phantom and a pelvis patient, and low-kVp CT angiography images for carotid artery assessment. Compared with the CT image without correction, the proposed method reduces the overall CT number error from over 200 HU to be less than 30 HU and increases the spatial uniformity by a factor of 1.5. Low-contrast object is faithfully retained after the proposed correction. An effective iterative algorithm for shading correction in CT imaging is proposed that is only assisted by general anatomical information without relying on prior knowledge. The proposed method is thus practical

  9. Crafting tolerance

    DEFF Research Database (Denmark)

    Kirchner, Antje; Freitag, Markus; Rapp, Carolin

    2011-01-01

    Ongoing changes in social structures, orientation, and value systems confront us with the growing necessity to address and understand transforming patterns of tolerance as well as specific aspects, such as social tolerance. Based on hierarchical analyses of the latest World Values Survey (2005......–08) and national statistics for 28 countries, we assess both individual and contextual aspects that influence an individual's perception of different social groupings. Using a social tolerance index that captures personal attitudes toward these groupings, we present an institutional theory of social tolerance. Our...

  10. Analysis of the U.S. forest tolerance patterns depending on current and future temperature and precipitation

    Science.gov (United States)

    Jean Lienard; John Harrison; Nikolay. Strigul

    2015-01-01

    Forested ecosystems are shaped by climate, soil and biotic interactions, resulting in constrained spatial distribution of species and biomes. Tolerance traits of species determine their fundamental ecological niche, while biotic interactions narrow tree distributions to the realized niche. In particular, shade, drought and waterlogging tolerances have been well-...

  11. Evaluation of a standard shade guide for color change after disinfection.

    Science.gov (United States)

    Pohjola, Randall M; Hackman, Steven T; Browning, William D

    2007-09-01

    To determine if surface disinfectants cause a change in the shade perception of a standard Classic Vitapan shade guide. Consistency in shade selection for dental restorations involves many factors, and one of the most important is the shade tabs used in the selection process. Ten shade tabs each of shades B2, D2, C1, and A3.5 were selected from the Classic Vitapan shade guide (Vident). All tabs were measured with the EasyShade shade device (Vident) at baseline. Three tabs of each shade were set aside as controls. The other 7 tabs of each shade were treated with the surface disinfectant Cavicide (Metrex Research) for 480 cycles to simulate a year's usage. After each 480 cycles, all the tabs were again measured with the EasyShade. This process was repeated to simulate 2 and 3 years of use. The data were analyzed to calculate the delta E 2000 for any change. A statistically significant increase was observed in the value (L*) and chroma (C*) after 2 and 3 years of simulated treatments. These changes were not perceptible to the clinician. The authors suggest that 1 standard shade guide be set aside to compare against those in clinical use to determine when they should be replaced.

  12. Heat stress in cows at pasture and benefit of shade in a temperate climate region

    Science.gov (United States)

    Veissier, Isabelle; Van laer, Eva; Palme, Rupert; Moons, Christel P. H.; Ampe, Bart; Sonck, Bart; Andanson, Stéphane; Tuyttens, Frank A. M.

    2017-11-01

    Under temperate climates, cattle are often at pasture in summer and are not necessarily provided with shade. We aimed at evaluating in a temperate region (Belgium) to what extent cattle may suffer from heat stress (measured through body temperature, respiration rate and panting score, cortisol or its metabolites in milk, and feces on hot days) and at assessing the potential benefits of shade. During the summer of 2012, 20 cows were kept on pasture without access to shade. During the summer of 2011, ten cows had access to shade (young trees with shade cloth hung between them), whereas ten cows had no access. Climatic conditions were quantified by the Heat Load Index (HLI). In animals without access to shade respiration rates, panting scores, rectal temperatures, and milk cortisol concentrations increased as HLI increased in both 2011 and 2012. Fecal cortisol metabolites varied with HLI in 2011 only. When cattle had access to shade, their use of shade increased as the HLI increased. This effect was more pronounced during the last part of the summer, possibly due to better acquaintance with the shade construction. In this case, shade use increased to 65% at the highest HLI (79). Shade tempered the effects on respiration, rectal temperature, and fecal cortisol metabolites. Milk cortisol was not influenced by HLI for cows using shade for > 10% of the day. Therefore, even in temperate areas, cattle may suffer from heat when they are at pasture in summer and providing shade can reduce such stress.

  13. FeedbackBetweenHumanActivitiesAndTerrestrialCarbonCyclesInSystemsOfShadeCoffeePro ductionInMexico

    Science.gov (United States)

    Pena Del Valle, A. E.; Perez-Samayoa, I. A.

    2007-12-01

    Coffee production in Mexico is carried out within a strong natural context. Coffee is grown under a canopy of several native and introduced tree species. This fact ensures a greater diversity of natural resources and environmental services available for local inhabitants to sustain their livelihoods. However, the lack of opportunities for coffee farmers is increasing the demand over the remaining forest areas by exacerbating non- sustainable timber extraction practices and promoting conversion of forests to pasture lands. This situation hampers the landscapes equilibrium and threatens the wellbeing of rural livelihoods. To understand the interactions between human activities and ecological functions associated with shaded coffee systems, this research has explored the extent to which socio-economic and cultural factors have influenced the use and management of natural resources sustaining coffee livelihoods. At the same time, it examines how customary patterns of resource use have induced changes in the terrestrial carbon cycle at the local level. The empirical study was carried out in a coffee-growing region in Mexico. It involved substantial fieldwork, use of satellite imagery, and participatory research methods in order to gauge a variety of biophysical and socio- economic factors, including forest cover, land use, and carbon balances, as well as, farming practices and off- farming strategies. In addition, a livelihood perspective was applied to approach the linkages between the management of natural resources, the environmental goods and services, and the socio-economic conditions in the coffee-growing region. The empirical evidence from the research marks out shade coffee systems as important supporters for broader natural systems as suppliers of environmental services. However, it also suggests that non-climatic factors might have significant impacts on the local environment and therefore on the terrestrial carbon cycle. According to the research estimations

  14. Modeling percent tree canopy cover: a pilot study

    Science.gov (United States)

    John W. Coulston; Gretchen G. Moisen; Barry T. Wilson; Mark V. Finco; Warren B. Cohen; C. Kenneth Brewer

    2012-01-01

    Tree canopy cover is a fundamental component of the landscape, and the amount of cover influences fire behavior, air pollution mitigation, and carbon storage. As such, efforts to empirically model percent tree canopy cover across the United States are a critical area of research. The 2001 national-scale canopy cover modeling and mapping effort was completed in 2006,...

  15. Canopy Photosynthesis: From Basics to Applications

    NARCIS (Netherlands)

    Hikosaka, Kouki; Niinemets, Ülo; Anten, N.P.R.

    2016-01-01

    A plant canopy, a collection of leaves, is an ecosystem-level unit of photosynthesis that assimilates carbon dioxide and exchanges other gases and energy with the atmosphere in a manner highly sensitive to ambient conditions including atmospheric carbon dioxide and water vapor concentrations, light

  16. FULLY AUTOMATED GIS-BASED INDIVIDUAL TREE CROWN DELINEATION BASED ON CURVATURE VALUES FROM A LIDAR DERIVED CANOPY HEIGHT MODEL IN A CONIFEROUS PLANTATION

    Directory of Open Access Journals (Sweden)

    R. J. L. Argamosa

    2016-06-01

    Full Text Available The generation of high resolution canopy height model (CHM from LiDAR makes it possible to delineate individual tree crown by means of a fully-automated method using the CHM’s curvature through its slope. The local maxima are obtained by taking the maximum raster value in a 3 m x 3 m cell. These values are assumed as tree tops and therefore considered as individual trees. Based on the assumptions, thiessen polygons were generated to serve as buffers for the canopy extent. The negative profile curvature is then measured from the slope of the CHM. The results show that the aggregated points from a negative profile curvature raster provide the most realistic crown shape. The absence of field data regarding tree crown dimensions require accurate visual assessment after the appended delineated tree crown polygon was superimposed to the hill shaded CHM.

  17. Within-canopy sesquiterpene ozonolysis in Amazonia

    Science.gov (United States)

    Jardine, K.; YañEz Serrano, A.; Arneth, A.; Abrell, L.; Jardine, A.; van Haren, J.; Artaxo, P.; Rizzo, L. V.; Ishida, F. Y.; Karl, T.; Kesselmeier, J.; Saleska, S.; Huxman, T.

    2011-10-01

    Through rapid reactions with ozone, which can initiate the formation of secondary organic aerosols, the emission of sesquiterpenes from vegetation in Amazonia may have significant impacts on tropospheric chemistry and climate. Little is known, however, about sesquiterpene emissions, transport, and chemistry within plant canopies owing to analytical difficulties stemming from very low ambient concentrations, high reactivities, and sampling losses. Here, we present ambient sesquiterpene concentration measurements obtained during the 2010 dry season within and above a primary tropical forest canopy in Amazonia. We show that by peaking at night instead of during the day, and near the ground instead of within the canopy, sesquiterpene concentrations followed a pattern different from that of monoterpenes, suggesting that unlike monoterpene emissions, which are mainly light dependent, sesquiterpene emissions are mainly temperature dependent. In addition, we observed that sesquiterpene concentrations were inversely related with ozone (with respect to time of day and vertical concentration), suggesting that ambient concentrations are highly sensitive to ozone. These conclusions are supported by experiments in a tropical rain forest mesocosm, where little atmospheric oxidation occurs and sesquiterpene and monoterpene concentrations followed similar diurnal patterns. We estimate that the daytime dry season ozone flux of -0.6 to -1.5 nmol m-2 s-1 due to in-canopy sesquiterpene reactivity could account for 7%-28% of the net ozone flux. Our study provides experimental evidence that a large fraction of total plant sesquiterpene emissions (46%-61% by mass) undergo within-canopy ozonolysis, which may benefit plants by reducing ozone uptake and its associated oxidative damage.

  18. Canopy arthropod responses to experimental canopy opening and debris deposition in a tropical rainforest subject to hurricanes

    Science.gov (United States)

    Timothy D. Schowalter; Michael R. Willig; Steven J. Presley

    2014-01-01

    We analyzed responses of canopy arthropods on seven representative early and late successional overstory and understory tree species to a canopy trimming experiment designed to separate effects of canopy opening and debris pulse (resulting from hurricane disturbance) in a tropical rainforest ecosystem at the Luquillo Experimental Forest Long-Term Ecological Research (...

  19. Effects of shading on Vallisneria natans (Lour.) H. Hara growth

    DEFF Research Database (Denmark)

    Fox, Anthony David; Meng, F; Shen, X

    2013-01-01

    Effects of surface shading were measured on above- and below-ground biomass and fruit production of Vallisneria natans (Lour.) H. Hara plants grown from seed in replicated microcosm experiments, based on a control (no shading) and four treatments (25%, 50%, 75% and 90% shading). Above- and below-...... spp. at seasonally inundated wetlands in the Yangtze River floodplain could, by shading, have contributed to the reduction in annual biomass and seed production of V. natans, contributing to declines in distribution and abundance....

  20. Evaluation of an optimized shade guide made from porcelain powder mixtures.

    Science.gov (United States)

    Wang, Peng; Wei, Jiaqiang; Li, Qing; Wang, Yining

    2014-12-01

    Color errors associated with current shade guides and problems with color selection and duplication are still challenging for restorative dentists. The purpose of this study was to evaluate an optimized shade guide for visual shade duplication. Color distributions (L*, a*, and b*) of the maxillary left central incisors of 236 participants, whose ages ranged from 20 to 60, were measured with a spectrophotometer. Based on this color map, an optimized shade guide was designed with 14 shade tabs evenly distributed within the given color range of the natural incisors. The shade tabs were fabricated with porcelain powder mixtures and conventional laboratory procedures. A comparison of shade duplication by using the optimized and Vitapan Classical shade guides was conducted. Thirty Chinese participants were involved, and the colors of the left maxillary incisors were selected by using 2 shade guides. Metal ceramic crowns were fabricated according to the results of the shade selection. The colors of the shade tabs, natural teeth, and the ceramic crowns were measured with a spectrophotometer. The color differences among the natural teeth, the shade tabs, and the corresponding metal ceramic crowns were calculated and analyzed (α=.017). Significant differences were found in both phases of shade determination and shade duplication (P<.017). The total number of color errors with the optimized shade guide was 3.5, which was significantly less than that of Vitapan, 5.1 (P<.001). The optimized shade guide system improved performance not only in the color selection phase but also in the color of the fabricated crowns. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  1. Reliability of shade selection using an intraoral spectrophotometer.

    Science.gov (United States)

    Witkowski, Siegbert; Yajima, Nao-Daniel; Wolkewitz, Martin; Strub, Jorge R

    2012-06-01

    In this study, we evaluate the accuracy and reproducibility of human tooth shade selection using a digital spectrophotometer. Variability among examiners and illumination conditions were tested for possible influence on measurement reproducibility. Fifteen intact anterior teeth of 15 subjects were evaluated for their shade using a digital spectrophotometer (Crystaleye, Olympus, Tokyo, Japan) by two examiners under the same light conditions representing a dental laboratory situation. Each examiner performed the measurement ten times on the labial surface of each tooth containing three evaluation sides (cervical, body, incisal). Commission International on Illumination color space values for L* (lightness), a* (red/green), and b* (yellow/blue) were obtained from each evaluated side. Examiner 2 repeated the measurements of the same subjects under different light conditions (i.e., a dental unit with a chairside lamp). To describe measurement precision, the mean color difference from the mean metric was used. The computed confidence interval (CI) value 5.228 (4.6598-5.8615) reflected (represented) the validity of the measurements. Least square mean analysis of the values obtained by examiners 1 and 2 or under different illumination conditions revealed no statistically significant differences (CI = 95%). Within the limits of the present study, the accuracy and reproducibility of dental shade selection using the tested spectrophotometer with respect to examiner and illumination conditions reflected the reliability of this device. This study suggests that the tested spectrophotometer can be recommended for the clinical application of shade selection.

  2. Adaptive heating, ventilation and solar shading for dwellings

    NARCIS (Netherlands)

    Alders, E.E.

    2017-01-01

    Calculation of various strategies for the heating of, and the prevention of overheating in, a Dutch standard dwelling that includes (automated) adaptive ventilation systems and solar shading to maintain indoor temperatures at acceptably comfortable temperatures informs this analysis of the costs,

  3. Evaluating Accuracy of the Sunnova Pro Platform Shade Measurement

    Energy Technology Data Exchange (ETDEWEB)

    2018-01-11

    Sunnova's new solar energy design platform, Sunnova Pro, automatically generates a 3D model of a building and surrounding shading objects. The product is designed to automate the process of engineering a system, sizing batteries and preparing sales proposals.

  4. Shades of African values and interests in Nigeria's international ...

    African Journals Online (AJOL)

    Shades of African values and interests in Nigeria's international relations: investigating the gains and the costs, 1960 – 2014. ... of policies that ensure that the country recovers all she lost in her years of naivety in I.R. The study adopted the historical methodology which emphasizes critical analyses and interpretation of facts.

  5. The use of shaded fuelbreaks in landscape fire management

    Science.gov (United States)

    James K. Agee; Bernie Bahro; Mark A. Finney; Philip N. Omi; David B. Sapsis; Carl N. Skinner; Jan W. van Wagtendonk; C. Phillip Weatherspoon

    2000-01-01

    Shaded fuelbreaks and larger landscape fuel treatments, such as prescribed fire, are receiving renewed interest as forest protection strategies in the western United States. The effectiveness of fuelbreaks remains a subject of debate because of differing fuelbreak objectives, prescriptions for creation and maintenance, and their placement in landscapes with differing...

  6. Microclimate, canopy structure and photosynthesis in canopies of three contrasting temperate forage grasses. III. Canopy photosynthesis, individual leaf photosynthesis and the distribution of current assimilate

    Energy Technology Data Exchange (ETDEWEB)

    Sheehy, J E

    1977-01-01

    The rates of canopy and individual leaf photosynthesis and /sup 14/C distribution for three temperate forage grasses Lolium perenne cv. S24, L. perenne cv. Reveille and Festuca arundinacea cv. S170 were determined in the field during a summer growth period. Canopy photosynthesis declined as the growth period progressed, reflecting a decline in the photosynthetic capacity of successive youngest fully expanded leaves. The decline in the maximum photosynthetic capacity of the canopies was correlated with a decline in their quantum efficiencies at low irradiance. Changes in canopy structure resulted in changes in canopy net photosynthesis and dark respiration. No clear relationships between changes in the environment and changes in canopy net photosynthesis and dark respiration were established. The relative distributions of /sup 14/C in the shoots of the varieties gave a good indication of the amount of dry matter per ground area in the varieties. 21 references, 4 figures, 1 table.

  7. Radiation and nitrogen use at the leaf and canopy level by wheat and oilseed rape during the critical period for grain number definition

    International Nuclear Information System (INIS)

    Dreccer, M.F.; Schapendonk, H.C.M.; Oijen, M. van; Pot, C.S.; Rabbinge, R.

    2000-01-01

    During the critical period for grain number definition, the amount of biomass produced per unit absorbed radiation is more sensitive to nitrogen (N) supply in oilseed rape than in wheat, and reaches a higher value at high N. This response was investigated by combining experimental and modelling work. Oilseed rape and wheat were grown at three levels of N supply, combined with two levels of plant density at high N supply. Canopy photosynthesis and daytime radiation use efficiency (RUE A ) were calculated with a model based on observed N-dependent leaf photosynthesis and observed canopy vertical distribution of light and leaf N. In oilseed rape, RUE A was higher than in wheat and, in contrast to wheat, the sensitivity to canopy leaf N content increased from the start to the end of the critical period. These results were partly explained by the higher leaf photosynthesis in oilseed rape vs wheat. In addition, oilseed rape leaves were increasingly shaded by the inflorescence. Thus, RUE A increased because more leaves were operating at non-saturating light levels. In both species, the vertical distribution of leaf N was close to that optimising canopy photosynthesis. The results are discussed in relation to possibilities for improvement of N productivity in these crops. (author)

  8. Improvement of Shade Resilience in Photovoltaic Modules Using Buck Converters in a Smart Module Architecture

    NARCIS (Netherlands)

    Golroodbari, S. Mirbagheri; Waal, Arjen. de; Sark, Wilfried van

    2018-01-01

    Partial shading has a nonlinear effect on the performance of photovoltaic (PV) modules. Different methods of optimizing energy harvesting under partial shading conditions have been suggested to mitigate this issue. In this paper, a smart PV module architecture is proposed for improvement of shade

  9. The roles of dimensionality, canopies and complexity in ecosystem monitoring.

    Directory of Open Access Journals (Sweden)

    Christopher H R Goatley

    Full Text Available Canopies are common among autotrophs, increasing their access to light and thereby increasing competitive abilities. If viewed from above canopies may conceal objects beneath them creating a 'canopy effect'. Due to complexities in collecting 3-dimensional data, most ecosystem monitoring programmes reduce dimensionality when sampling, resorting to planar views. The resultant 'canopy effects' may bias data interpretation, particularly following disturbances. Canopy effects are especially relevant on coral reefs where coral cover is often used to evaluate and communicate ecosystem health. We show that canopies hide benthic components including massive corals and algal turfs, and as planar views are almost ubiquitously used to monitor disturbances, the loss of vulnerable canopy-forming corals may bias findings by presenting pre-existing benthic components as an altered system. Our reliance on planar views in monitoring ecosystems, especially coral cover on reefs, needs to be reassessed if we are to better understand the ecological consequences of ever more frequent disturbances.

  10. Biophysical information in asymmetric and symmetric diurnal bidirectional canopy reflectance

    Science.gov (United States)

    Vanderbilt, Vern C.; Caldwell, William F.; Pettigrew, Rita E.; Ustin, Susan L.; Martens, Scott N.; Rousseau, Robert A.; Berger, Kevin M.; Ganapol, B. D.; Kasischke, Eric S.; Clark, Jenny A.

    1991-01-01

    The authors present a theory for partitioning the information content in diurnal bidirectional reflectance measurements in order to detect differences potentially related to biophysical variables. The theory, which divides the canopy reflectance into asymmetric and symmetric functions of solar azimuth angle, attributes asymmetric variation to diurnal changes in the canopy biphysical properties. The symmetric function is attributed to the effects of sunlight interacting with a hypothetical average canopy which would display the average diurnal properties of the actual canopy. The authors analyzed radiometer data collected diurnally in the Thematic Mapper wavelength bands from two walnut canopies that received differing irrigation treatments. The reflectance of the canopies varied with sun and view angles and across seven bands in the visible, near-infrared, and middle infrared wavelength regions. Although one of the canopies was permanently water stressed and the other was stressed in mid-afternoon each day, no water stress signature was unambiguously evident in the reflectance data.

  11. Chemical and physical environmental conditions underneath mat- and canopy-forming macroalgae, and their effects on understorey corals.

    Science.gov (United States)

    Hauri, Claudine; Fabricius, Katharina E; Schaffelke, Britta; Humphrey, Craig

    2010-09-13

    Disturbed coral reefs are often dominated by dense mat- or canopy-forming assemblages of macroalgae. This study investigated how such dense macroalgal assemblages change the chemical and physical microenvironment for understorey corals, and how the altered environmental conditions affect the physiological performance of corals. Field measurements were conducted on macroalgal-dominated inshore reefs in the Great Barrier Reef in quadrats with macroalgal biomass ranging from 235 to 1029 g DW m(-2) dry weight. Underneath mat-forming assemblages, the mean concentration of dissolved oxygen was reduced by 26% and irradiance by 96% compared with conditions above the mat, while concentrations of dissolved organic carbon and soluble reactive phosphorous increased by 26% and 267%, respectively. The difference was significant but less pronounced under canopy-forming assemblages. Dissolved oxygen declined and dissolved inorganic carbon and alkalinity increased with increasing algal biomass underneath mat-forming but not under canopy-forming assemblages. The responses of corals to conditions similar to those found underneath algal assemblages were investigated in an aquarium experiment. Coral nubbins of the species Acropora millepora showed reduced photosynthetic yields and increased RNA/DNA ratios when exposed to conditions simulating those underneath assemblages (pre-incubating seawater with macroalgae, and shading). The magnitude of these stress responses increased with increasing proportion of pre-incubated algal water. Our study shows that mat-forming and, to a lesser extent, canopy-forming macroalgal assemblages alter the physical and chemical microenvironment sufficiently to directly and detrimentally affect the metabolism of corals, potentially impeding reef recovery from algal to coral-dominated states after disturbance. Macroalgal dominance on coral reefs therefore simultaneously represents a consequence and cause of coral reef degradation.

  12. Chemical and physical environmental conditions underneath mat- and canopy-forming macroalgae, and their effects on understorey corals.

    Directory of Open Access Journals (Sweden)

    Claudine Hauri

    2010-09-01

    Full Text Available Disturbed coral reefs are often dominated by dense mat- or canopy-forming assemblages of macroalgae. This study investigated how such dense macroalgal assemblages change the chemical and physical microenvironment for understorey corals, and how the altered environmental conditions affect the physiological performance of corals. Field measurements were conducted on macroalgal-dominated inshore reefs in the Great Barrier Reef in quadrats with macroalgal biomass ranging from 235 to 1029 g DW m(-2 dry weight. Underneath mat-forming assemblages, the mean concentration of dissolved oxygen was reduced by 26% and irradiance by 96% compared with conditions above the mat, while concentrations of dissolved organic carbon and soluble reactive phosphorous increased by 26% and 267%, respectively. The difference was significant but less pronounced under canopy-forming assemblages. Dissolved oxygen declined and dissolved inorganic carbon and alkalinity increased with increasing algal biomass underneath mat-forming but not under canopy-forming assemblages. The responses of corals to conditions similar to those found underneath algal assemblages were investigated in an aquarium experiment. Coral nubbins of the species Acropora millepora showed reduced photosynthetic yields and increased RNA/DNA ratios when exposed to conditions simulating those underneath assemblages (pre-incubating seawater with macroalgae, and shading. The magnitude of these stress responses increased with increasing proportion of pre-incubated algal water. Our study shows that mat-forming and, to a lesser extent, canopy-forming macroalgal assemblages alter the physical and chemical microenvironment sufficiently to directly and detrimentally affect the metabolism of corals, potentially impeding reef recovery from algal to coral-dominated states after disturbance. Macroalgal dominance on coral reefs therefore simultaneously represents a consequence and cause of coral reef degradation.

  13. Mapping Urban Tree Canopy Coverage and Structure using Data Fusion of High Resolution Satellite Imagery and Aerial Lidar

    Science.gov (United States)

    Elmes, A.; Rogan, J.; Williams, C. A.; Martin, D. G.; Ratick, S.; Nowak, D.

    2015-12-01

    Urban tree canopy (UTC) coverage is a critical component of sustainable urban areas. Trees provide a number of important ecosystem services, including air pollution mitigation, water runoff control, and aesthetic and cultural values. Critically, urban trees also act to mitigate the urban heat island (UHI) effect by shading impervious surfaces and via evaporative cooling. The cooling effect of urban trees can be seen locally, with individual trees reducing home HVAC costs, and at a citywide scale, reducing the extent and magnitude of an urban areas UHI. In order to accurately model the ecosystem services of a given urban forest, it is essential to map in detail the condition and composition of these trees at a fine scale, capturing individual tree crowns and their vertical structure. This paper presents methods for delineating UTC and measuring canopy structure at fine spatial resolution (body of methods, relying on a data fusion method to combine the information contained in high resolution WorldView-3 satellite imagery and aerial lidar data using an object-based image classification approach. The study area, Worcester, MA, has recently undergone a large-scale tree removal and reforestation program, following a pest eradication effort. Therefore, the urban canopy in this location provides a wide mix of tree age class and functional type, ideal for illustrating the effectiveness of the proposed methods. Early results show that the object-based classifier is indeed capable of identifying individual tree crowns, while continued research will focus on extracting crown structural characteristics using lidar-derived metrics. Ultimately, the resulting fine resolution UTC map will be compared with previously created UTC maps of the same area but for earlier dates, producing a canopy change map corresponding to the Worcester area tree removal and replanting effort.

  14. Seasonal differences in freezing tolerance of yellow-cedar and western hemlock trees at a site affected by yellow-cedar decline

    Science.gov (United States)

    Paul G. Schaberg; Paul E. Hennon; Amore, David V. D; Gary J. Hawley; Catherine H. Borer; Catherine H. Borer

    2005-01-01

    To assess whether inadequate cold hardiness could be a contributor to yellow-cedar (Chamaecyparis nootkatensis (D. Don) Spach) decline, we measured the freezing tolerance of foliage from yellow-cedar trees in closed-canopy (nondeclining) and open-canopy (declining at elevations below 130 m) stands at three sites along an elevational gradient in the heart of the decline...

  15. Cockpit canopy shattering using exploding wire techniques

    International Nuclear Information System (INIS)

    Novac, B M; Smith, I R; Downs, P R; Marston, P; Fahey, D

    2007-01-01

    This paper presents the principal experimental results provided by a preliminary investigation into the possibility of using exploding wire (EW) techniques to shatter the plastic cockpit canopy of a modern jet aircraft. The data provided forms the basis for a qualitative understanding of the physics of interaction between the plasma produced by an EW and the surrounding elasto-plastic material in which the wire is embedded. To optimize the shock-wave 'clean cutting' effect, the significance of the material, the dimensions of the exploding wire and the amplitude of the current and voltage pulses are all considered. This leads to important conclusions concerning both the characteristics of the EW and the optimum arrangement of the electrical circuit, with the single most important optimization factor being the peak electrical power input to the EW, rather than the dissipated Joule energy. A full-scale system relevant to an actual cockpit canopy shattering is outlined and relevant results are presented and discussed

  16. Om tolerance

    DEFF Research Database (Denmark)

    Huggler, Jørgen

    2007-01-01

    Begrebet tolerance og dets betydninger diskuteres med henblik på en tydeliggørelse af begrebets forbindelse med stat, religion, ytringsfrihed, skeptisk erkendelsesteori, antropologi og pædagogik.......Begrebet tolerance og dets betydninger diskuteres med henblik på en tydeliggørelse af begrebets forbindelse med stat, religion, ytringsfrihed, skeptisk erkendelsesteori, antropologi og pædagogik....

  17. Typology of building shading elements on Jalan Sudirman corridor in Pekanbaru

    Science.gov (United States)

    Faisal, G.; Aldy, P.

    2016-04-01

    In 2013, temperature in Pekanbaru was between 22.60°C and 34.6°C with humidity 79.14 percent. This condition has increase the concern of energy utilization to building comfort. Buildings have the biggest energy consuming due to the use of air conditioner in Pekanbaru. One effort to reduced energy is shading devices application. Application of air conditioner need huge energy, replaced natural circulation with architecture elements to reduced building thermal. This research study about system and building shading devices types that influence building thermal in Pekanbaru so that knowing characteristics and elements form. This study aims to determine and identify of systems and building elements types in Pekanbaru, which the element forms to conquer in climate condition. Qualitative method with rationalistic-paradigm has used to identify typology of building shading devices on Jalan Sudirman corridor. The research orientation on typology theory, thermal theory, and building shading device to identification of building shading device types on Jalan Sudirman corridor. Based on the survey result, there are 2 type of building shading devices on Jalan Sudirman Pekanbaru which is based on forms and quantity of shading. The types are building shading devices based on shading quantity and building shading devices based on shading forms.

  18. Building Applications, Opportunities and Challenges of Active Shading Systems: A State-of-the-Art Review

    Directory of Open Access Journals (Sweden)

    Joud Al Dakheel

    2017-10-01

    Full Text Available Active shading systems in buildings have emerged as a high performing shading solution that selectively and optimally controls daylight and heat gains. Active shading systems are increasingly used in buildings, due to their ability to mainly improve the building environment, reduce energy consumption and in some cases generate energy. They may be categorized into three classes: smart glazing, kinetic shading and integrated renewable energy shading. This paper reviews the current status of the different types in terms of design principle and working mechanism of the systems, performance, control strategies and building applications. Challenges, limitations and future opportunities of the systems are then discussed. The review highlights that despite its high initial cost, the electrochromic (EC glazing is the most applied smart glazing due to the extensive use of glass in buildings under all climatic conditions. In terms of external shadings, the rotating shading type is the predominantly used one in buildings due to its low initial cost. Algae façades and folding shading systems are still emerging types, with high initial and maintenance costs and requiring specialist installers. The algae façade systems and PV integrated shading systems are a promising solution due to their dual benefits of providing shading and generating electricity. Active shading systems were found to save 12 to 50% of the building cooling electricity consumption.

  19. Evaluation of Dental Shade Guide Variability Using Cross-Polarized Photography.

    Science.gov (United States)

    Gurrea, Jon; Gurrea, Marta; Bruguera, August; Sampaio, Camila S; Janal, Malvin; Bonfante, Estevam; Coelho, Paulo G; Hirata, Ronaldo

    2016-01-01

    This study evaluated color variability in the A hue between the VITA Classical (VITA Zahnfabrik) shade guide and four other VITA-coded ceramic shade guides using a Canon EOS 60D camera and software (Photoshop CC, Adobe). A total of 125 photographs were taken, 5 per shade tab for each of 5 shades (A1 to A4) from the following shade guides: VITA Classical (control), IPS e.max Ceram (Ivoclar Vivadent), IPS d.SIGN (Ivoclar Vivadent), Initial ZI (GC), and Creation CC (Creation Willi Geller). Photos were processed with Adobe Photoshop CC to allow standardized evaluation of hue, chroma, and value between shade tabs. None of the VITA-coded shade tabs fully matched the VITA Classical shade tab for hue, chroma, or value. The VITA-coded shade guides evaluated herein showed an overall unmatched shade in all tabs when compared with the control, suggesting that shade selection should be made using the guide produced by the manufacturer of the ceramic intended for the final restoration.

  20. Canopy soil bacterial communities altered by severing host tree limbs

    Directory of Open Access Journals (Sweden)

    Cody R. Dangerfield

    2017-09-01

    Full Text Available Trees of temperate rainforests host a large biomass of epiphytic plants, which are associated with soils formed in the forest canopy. Falling of epiphytic material results in the transfer of carbon and nutrients from the canopy to the forest floor. This study provides the first characterization of bacterial communities in canopy soils enabled by high-depth environmental sequencing of 16S rRNA genes. Canopy soil included many of the same major taxonomic groups of Bacteria that are also found in ground soil, but canopy bacterial communities were lower in diversity and contained different operational taxonomic units. A field experiment was conducted with epiphytic material from six Acer macrophyllum trees in Olympic National Park, Washington, USA to document changes in the bacterial communities of soils associated with epiphytic material that falls to the forest floor. Bacterial diversity and composition of canopy soil was highly similar, but not identical, to adjacent ground soil two years after transfer to the forest floor, indicating that canopy bacteria are almost, but not completely, replaced by ground soil bacteria. Furthermore, soil associated with epiphytic material on branches that were severed from the host tree and suspended in the canopy contained altered bacterial communities that were distinct from those in canopy material moved to the forest floor. Therefore, the unique nature of canopy soil bacteria is determined in part by the host tree and not only by the physical environmental conditions associated with the canopy. Connection to the living tree appears to be a key feature of the canopy habitat. These results represent an initial survey of bacterial diversity of the canopy and provide a foundation upon which future studies can more fully investigate the ecological and evolutionary dynamics of these communities.

  1. The impact of translucent fabric shades and control strategies on energy savings and visual quality

    Science.gov (United States)

    Wankanapon, Pimonmart

    Translucent fabric shades provide opportunities for building occupants to control sunlight penetration for heat reduction, thermal comfort, and visual quality. Regulating shades affects building energy and can potentially reduce the size of mechanical cooling systems. Shades are not normally included in energy model studies during the design process, even though shades potential impact energy use. This is because the occupants normally leave shades closed a large fraction of the time, but models are generally performed with no shades. Automatic shade control is now available, so it is necessary to understand the impact of shades on visual quality and their energy saving potential in order to optimize their overall performance. There are very limited studies that have address shades and their integrated performance on energy consumption and visual quality. Most of these do not reflected modern shade types and their application. The goals of this study are: First, to determine the impact of shades on total, heating, cooling and lighting energy savings with different design and operation parameters. Second, to study and develop different automatic shade control strategies to promote and optimize energy savings and visual quality. A simulation-based approach using EnergyPlus in a parametric study provide better understanding energy savings under different shade conditions. The parametric runs addressed various building parameters such as geometry, orientation, site climate, glazing/shade properties, and shade control strategies with integrated lighting control. The impact of shades was determined for total building and space heating, cooling and lighting energy savings. The effect of shades on visual quality was studied using EnergyPlus, AGI32 and DAYSIM for several indices such as daylight glare index (DGI), work plane illuminance, luminance ratios and view. Different shade control strategies and integrated lighting control were considered with two translucent fabric

  2. Color stability of shade guides after autoclave sterilization.

    Science.gov (United States)

    Schmeling, Max; Sartori, Neimar; Monteiro, Sylvio; Baratieri, Luiz

    2014-01-01

    This study evaluated the influence of 120 autoclave sterilization cycles on the color stability of two commercial shade guides (Vita Classical and Vita System 3D-Master). The specimens were evaluated by spectrophotometer before and after the sterilization cycles. The color was described using the three-dimensional CIELab system. The statistical analysis was performed in three chromaticity coordinates, before and after sterilization cycles, using the paired samples t test. All specimens became darker after autoclave sterilization cycles. However, specimens of Vita Classical became redder, while those of the Vita System 3D-Master became more yellow. Repeated cycles of autoclave sterilization caused statistically significant changes in the color coordinates of the two shade guides. However, these differences are considered clinically acceptable.

  3. Topographical Hill Shading Map Production Based Tianditu (map World)

    Science.gov (United States)

    Wang, C.; Zha, Z.; Tang, D.; Yang, J.

    2018-04-01

    TIANDITU (Map World) is the public version of National Platform for Common Geospatial Information Service, and the terrain service is an important channel for users on the platform. With the development of TIANDITU, topographical hill shading map production for providing and updating global terrain map on line becomes necessary for the characters of strong intuition, three-dimensional sense and aesthetic effect. As such, the terrain service of TIANDITU focuses on displaying the different scales of topographical data globally. And this paper mainly aims to research the method of topographical hill shading map production globally using DEM (Digital Elevation Model) data between the displaying scales about 1 : 140,000,000 to 1 : 4,000,000, corresponded the display level from 2 to 7 on TIANDITU website.

  4. Height development of shade-tolerant conifer saplings in multiaged Acadian forest stands

    Science.gov (United States)

    Andrew R. Moores; Robert S. Seymour; Laura S. Kenefic

    2007-01-01

    Understory growth dynamics of northern conifer species were studied in four stands managed under multiaged silvicultural systems in eastern Maine. Height growth of Picea rubens Sarg., Abies balsamea (L.) Mill., and Tsuga canadensis (L.) Carr. saplings between 0.5 and 6.0 m in height was related to the proportion...

  5. Architecture of 53 rain forest tree species differing in adult stature and shade tolerance

    NARCIS (Netherlands)

    Poorter, L.; Bongers, F.J.J.M.; Sterck, F.J.; Wöll, H.

    2003-01-01

    Tree architecture determines a tree's light capture, stability, and efficiency of crown growth. The hypothesis that light demand and adult stature of tree species within a community, independently of each other, determine species' architectural traits was tested by comparing 53 Liberian rain forest

  6. Algorithm for Extracting Digital Terrain Models under Forest Canopy from Airborne LiDAR Data

    Directory of Open Access Journals (Sweden)

    Almasi S. Maguya

    2014-07-01

    Full Text Available Extracting digital elevationmodels (DTMs from LiDAR data under forest canopy is a challenging task. This is because the forest canopy tends to block a portion of the LiDAR pulses from reaching the ground, hence introducing gaps in the data. This paper presents an algorithm for DTM extraction from LiDAR data under forest canopy. The algorithm copes with the challenge of low data density by generating a series of coarse DTMs by using the few ground points available and using trend surfaces to interpolate missing elevation values in the vicinity of the available points. This process generates a cloud of ground points from which the final DTM is generated. The algorithm has been compared to two other algorithms proposed in the literature in three different test sites with varying degrees of difficulty. Results show that the algorithm presented in this paper is more tolerant to low data density compared to the other two algorithms. The results further show that with decreasing point density, the differences between the three algorithms dramatically increased from about 0.5m to over 10m.

  7. Impact of Canopy Coupling on Canopy Average Stomatal Conductance Across Seven Tree Species in Northern Wisconsin

    Science.gov (United States)

    Ewers, B. E.; Mackay, D. S.; Samanta, S.; Ahl, D. E.; Burrows, S. S.; Gower, S. T.

    2001-12-01

    Land use changes over the last century in northern Wisconsin have resulted in a heterogeneous landscape composed of the following four main forest types: northern hardwoods, northern conifer, aspen/fir, and forested wetland. Based on sap flux measurements, aspen/fir has twice the canopy transpiration of northern hardwoods. In addition, daily transpiration was only explained by daily average vapor pressure deficit across the cover types. The objective of this study was to determine if canopy average stomatal conductance could be used to explain the species effects on tree transpiration. Our first hypothesis is that across all of the species, stomatal conductance will respond to vapor pressure deficit so as to maintain a minimum leaf water potential to prevent catostrophic cavitiation. The consequence of this hypothesis is that among species and individuals there is a proportionality between high stomatal conductance and the sensitivity of stomatal conductance to vapor pressure deficit. Our second hypothesis is that species that do not follow the proportionality deviate because the canopies are decoupled from the atmosphere. To test our two hypotheses we calculated canopy average stomatal conductance from sap flux measurements using an inversion of the Penman-Monteith equation. We estimated the canopy coupling using a leaf energy budget model that requires leaf transpiration and canopy aerodynamic conductance. We optimized the parameters of the aerodynamic conductance model using a Monte Carlo technique across six parameters. We determined the optimal model for each species by selecting parameter sets that resulted in the proportionality of our first hypothesis. We then tested the optimal energy budget models of each species by comparing leaf temperature and leaf width predicted by the models to measurements of each tree species. In red pine, sugar maple, and trembling aspen trees under high canopy coupling conditions, we found the hypothesized proportionality

  8. Quality and Quantity Evaluations of Shade Grown Forages

    Science.gov (United States)

    K. P. Ladyman; M. S. Kerley; R. L. Kallenbach; H. E. Garrett; J. W. Van Sambeek; N. E. Navarrete-Tindall

    2003-01-01

    Seven legumes were grown during the summer-fall of 2000, at the Horticulture and Agroforestry Research Center (39? 01 ' N, 92? 46' W) near New Franklin, MO. The forages were grown in 7.5L white pots placed on light-colored gravel either under full sunlight, 45% sunlight, or 20% sunlight created by a shade cloth over a rectangular frame. Drip irrigation was...

  9. Phytochrome A, phytochrome B and HY4 are involved in hypocotyl growth responses to natural radiation in Arabidopsis: weak de-etiolation of the phyA mutant under dense canopies

    International Nuclear Information System (INIS)

    Yanovsky, M.J.; Casal, J.J.; Whitelam, G.C.

    1995-01-01

    The roles of phytochrome A (phyA), phytochrome B (phyB) and a putative blue-light (BL) photoreceptor (HY4) in the control of hypocotyl growth by natural radiation were investigated using phyA, phyB and hy4 mutants of Arabidopsis thaliana. Full sunlight inhibited hypocotyl growth to a larger extent in wild-type (WT) than in phyA, phyB and, particularly, hy4 seedlings. In WT seedlings, hypocotyl growth was promoted by selectively lowering BL irradiance, lowering red-light (R) plus far-red-light (FR) irradiance or lowering the R/FR ratio (which was achieved either by increasing FR or by reducing R). The effects of lowering BL were reduced in hy4 and exaggerated in phyA seedlings. The effects of lowering R+FR were reduced in phyA and exaggerated in hy4 seedlings. Neither phyB nor hy4 mutants responded to low R/FR ratios. Neighbouring plants reflecting FR without shading caused subtle reductions of the R/FR ratio. This signal promoted hypocotyl growth in WT but not in phyA, phyB or hy4 seedlings. Intermediate canopy shade produced similar effects in all genotypes. Under deep shade, de-etiolation was severely impaired in phyA seedlings, which died prematurely. Thus, the FR ‘high-irradiance reaction’ mediated by phyA could be important for seedling survival under dense canopies. (author)

  10. Roles of Urban Tree Canopy and Buildings in Urban Heat Island Effects: Parameterization and Preliminary Results

    Science.gov (United States)

    Loughner, Christopher P.; Allen, Dale J.; Zhang, Da-Lin; Pickering, Kenneth E.; Dickerson, Russell R.; Landry, Laura

    2012-01-01

    Urban heat island (UHI) effects can strengthen heat waves and air pollution episodes. In this study, the dampening impact of urban trees on the UHI during an extreme heat wave in the Washington, D.C., and Baltimore, Maryland, metropolitan area is examined by incorporating trees, soil, and grass into the coupled Weather Research and Forecasting model and an urban canopy model (WRF-UCM). By parameterizing the effects of these natural surfaces alongside roadways and buildings, the modified WRF-UCM is used to investigate how urban trees, soil, and grass dampen the UHI. The modified model was run with 50% tree cover over urban roads and a 10% decrease in the width of urban streets to make space for soil and grass alongside the roads and buildings. Results show that, averaged over all urban areas, the added vegetation decreases surface air temperature in urban street canyons by 4.1 K and road-surface and building-wall temperatures by 15.4 and 8.9 K, respectively, as a result of tree shading and evapotranspiration. These temperature changes propagate downwind and alter the temperature gradient associated with the Chesapeake Bay breeze and, therefore, alter the strength of the bay breeze. The impact of building height on the UHI shows that decreasing commercial building heights by 8 m and residential building heights by 2.5 m results in up to 0.4-K higher daytime surface and near-surface air temperatures because of less building shading and up to 1.2-K lower nighttime temperatures because of less longwave radiative trapping in urban street canyons.

  11. Production of tropical forage grasses under different shading levels

    Directory of Open Access Journals (Sweden)

    Francisco Eduardo Torres

    2017-12-01

    Full Text Available This study aimed to evaluate the forage production of three tropical forage grasses under different shading levels. The experiment was conducted in a greenhouse at Universidade Estadual de Mato Grosso do Sul, University Unit of Aquidauana (UEMS/UUA, in a soil classified as Ultisol sandy loam texture. The treatments consisted of three grasses species combinations (B. brizantha cv. Marandu, B. decumbens cv. Basilisck and Panicum maximum cv. Tanzania, submitted to four shading levels (0, 30, 50 and 75%, arranged in a completely randomized blocks design in a factorial 3 x 4, with eight replications. After harvest, the plants were separated into shoot and roots for determination of shoot fresh mass (SFM, shoot dry mass (SDM and roots dry mass production. After analysis of variance, the qualitative factor was subjected to comparison of averages by Tukey’s test, and the quantitative factor to analysis of polynomial regression, being interactions appropriately unfolded. It was verified that B. decumbens, by its linearly increasing production of forage and less decrease of root formation, is the most recommended for shading conditions compared to grasses Tanzania and Marandu.

  12. Effect of abutment shade, ceramic thickness, and coping type on the final shade of zirconia all-ceramic restorations: in vitro study of color masking ability.

    Science.gov (United States)

    Oh, Seon-Hee; Kim, Seok-Gyu

    2015-10-01

    The aim of the study was to evaluate the effect of abutment shade, ceramic thickness, and coping type on the final shade of zirconia all-ceramic restorations. Three different types of disk-shaped zirconia coping specimens (Lava, Cercon, Zirkonzahn: ø10 mm × 0.4 mm) were fabricated and veneered with IPS e.max Press Ceram (shade A2), for total thicknesses of 1 and 1.5 mm. A total of sixty zirconia restoration specimens were divided into six groups based on their coping types and thicknesses. The abutment specimens (ø10 mm × 7 mm) were prepared with gold alloy, base metal (nickel-chromium) alloy, and four different shades (A1, A2, A3, A4) of composite resins. The average L*, a*, b* values of the zirconia specimens on the six abutment specimens were measured with a dental colorimeter, and the statistical significance in the effects of three variables was analyzed by using repeated measures analysis of variance (α=.05).The average shade difference (ΔE) values of the zirconia specimens between the A2 composite resin abutment and other abutments were also evaluated. The effects of zirconia specimen thickness (Pabutment shade (Pabutments was higher (close to the acceptability threshold of 5.5 ΔE) than th ose between the A2 composite resin and other abutments. This in-vitro study demonstrated that abutment shade, ceramic thickness, and coping type affected the resulting shade of zirconia restorations.

  13. Scaling up carbonyl sulfide (COS) fluxes from leaf and soil to the canopy

    Science.gov (United States)

    Yang, Fulin; Yakir, Dan

    2016-04-01

    from soil and leaf chamber to canopy scale was possible by estimating LAI, and differential consideration of soil surface components (shaded vs. exposed fractions). 4) Diurnal changes in the atmospheric concentrations of COS and CO2 above the canopy showed complex patterns with opposite trends after sunrise that could be explain by the development of the planetary boundary layer 5) COS-based estimate of GPP can be improved by adopting light dependent LRU, around the mean value of ~1.6, and correcting for soil COS fluxes based on soil temperature and canopy cover estimates, and coupled COS/CO2 concentration measurements provide useful information on boundary layer dynamics.

  14. Implementation of a subcanopy solar radiation model on a forested headwater basin in the Southern Appalachians to estimate riparian canopy density and stream insolation for stream temperature models

    Science.gov (United States)

    Belica, L.; Petras, V.; Iiames, J. S., Jr.; Caldwell, P.; Mitasova, H.; Nelson, S. A. C.

    2016-12-01

    Water temperature is a key aspect of water quality and understanding how the thermal regimes of forested headwater streams may change in response to climatic and land cover changes is increasingly important to scientists and resource managers. In recent years, the forested mountain watersheds of the Southeastern U.S. have experienced changing climatic patterns as well as the loss of a keystone riparian tree species and anticipated hydrologic responses include lower summer stream flows and decreased stream shading. Solar radiation is the main source of thermal energy to streams and a key parameter in heat-budget models of stream temperature; a decrease in flow volume combined with a reduction in stream shading during summer have the potential to increase stream temperatures. The high spatial variability of forest canopies and the high spatio-temporal variability in sky conditions make estimating the solar radiation reaching small forested headwater streams difficult. The Subcanopy Solar Radiation Model (SSR) (Bode et al. 2014) is a GIS model that generates high resolution, spatially explicit estimates of solar radiation by incorporating topographic and vegetative shading with a light penetration index derived from leaf-on airborne LIDAR data. To evaluate the potential of the SSR model to provide estimates of stream insolation to parameterize heat-budget models, it was applied to the Coweeta Basin in the Southern Appalachians using airborne LIDAR (NCALM 2009, 1m resolution). The LIDAR derived canopy characteristics were compared to current hyperspectral images of the canopy for changes and the SSR estimates of solar radiation were compared with pyranometer measurements of solar radiation at several subcanopy sites during the summer of 2016. Preliminary results indicate the SSR model was effective in identifying variations in canopy density and light penetration, especially in areas associated with road and stream corridors and tree mortality. Current LIDAR data and

  15. Mechanistic study of aerosol dry deposition on vegetated canopies

    International Nuclear Information System (INIS)

    Petroff, A.

    2005-04-01

    The dry deposition of aerosols onto vegetated canopies is modelled through a mechanistic approach. The interaction between aerosols and vegetation is first formulated by using a set of parameters, which are defined at the local scale of one surface. The overall deposition is then deduced at the canopy scale through an up-scaling procedure based on the statistic distribution parameters. This model takes into account the canopy structural and morphological properties, and the main characteristics of the turbulent flow. Deposition mechanisms considered are Brownian diffusion, interception, initial and turbulent impaction, initially with coniferous branches and then with entire canopies of different roughness, such as grass, crop field and forest. (author)

  16. Modeling directional thermal radiance from a forest canopy

    International Nuclear Information System (INIS)

    McGuire, M.J.; Balick, L.K.; Smith, J.A.; Hutchison, B.A.

    1989-01-01

    Recent advances in remote sensing technology have increased interest in utilizing the thermal-infared region to gain additional information about surface features such as vegetation canopies. Studies have shown that sensor view angle, canopy structure, and percentage of canopy coverage can affect the response of a thermal sensor. These studies have been primarily of agricultural regions and there have been relatively few examples describing the thermal characteristics of forested regions. This paper describes an extension of an existing thermal vegetation canopy radiance model which has been modified to partially account for the geometrically rough structure of a forest canopy. Fourier series expansion of a canopy height profile is used to calculate improved view factors which partially account for the directional variations in canopy thermal radiance transfers. The original and updated radiance model predictions are compared with experimental data obtained over a deciduous (oak-hickory) forest site. The experimental observations are also used to document azimuthal and nadir directional radiance variations. Maximum angular variations in measured canopy temperatures were 4–6°C (azimuth) and 2.5°C (nadir). Maximum angular variations in simulated temperatures using the modified rough surface model was 4°C. The rough surface model appeared to be sensitive to large gaps in the canopy height profile, which influenced the resultant predicted temperature. (author)

  17. Specular, diffuse and polarized imagery of an oat canopy

    Science.gov (United States)

    Vanderbilt, Vern C.; De Venecia, Kurt J.

    1988-01-01

    Light, polarized by specular reflection, has been found to be an important part of the light scattered by several measured plant canopies. The authors investigate for one canopy the relative importance of specularly reflected sunlight, specularly reflected light from other sources including skylight, and diffusely upwelling light. Polarization images are used to gain increased understanding of the radiation transfer process in a plant canopy. Analysis of the results suggests that properly analyzed polarized remotely sensed data, acquired under specific atmospheric conditions by a specially designed sensor, potentially provide measures of physiological and morphological states of plants in a canopy.

  18. Evaluation of one dimensional analytical models for vegetation canopies

    Science.gov (United States)

    Goel, Narendra S.; Kuusk, Andres

    1992-01-01

    The SAIL model for one-dimensional homogeneous vegetation canopies has been modified to include the specular reflectance and hot spot effects. This modified model and the Nilson-Kuusk model are evaluated by comparing the reflectances given by them against those given by a radiosity-based computer model, Diana, for a set of canopies, characterized by different leaf area index (LAI) and leaf angle distribution (LAD). It is shown that for homogeneous canopies, the analytical models are generally quite accurate in the visible region, but not in the infrared region. For architecturally realistic heterogeneous canopies of the type found in nature, these models fall short. These shortcomings are quantified.

  19. Spectroscopic Remote Sensing of Non-Structural Carbohydrates in Forest Canopies

    Directory of Open Access Journals (Sweden)

    Gregory P. Asner

    2015-03-01

    Full Text Available Non-structural carbohydrates (NSC are products of photosynthesis, and leaf NSC concentration may be a prognostic indicator of climate-change tolerance in woody plants. However, measurement of leaf NSC is prohibitively labor intensive, especially in tropical forests, where foliage is difficult to access and where NSC concentrations vary enormously by species and across environments. Imaging spectroscopy may allow quantitative mapping of leaf NSC, but this possibility remains unproven. We tested the accuracy of NSC remote sensing at leaf, canopy and stand levels using visible-to-shortwave infrared (VSWIR spectroscopy with partial least squares regression (PLSR techniques. Leaf-level analyses demonstrated the high precision (R2 = 0.69–0.73 and accuracy (%RMSE = 13%–14% of NSC estimates in 6136 live samples taken from 4222 forest canopy species worldwide. The leaf spectral data were combined with a radiative transfer model to simulate the role of canopy structural variability, which led to a reduction in the precision and accuracy of leaf NSC estimation (R2 = 0.56; %RMSE = 16%. Application of the approach to 79 one-hectare plots in Amazonia using the Carnegie Airborne Observatory VSWIR spectrometer indicated the good precision and accuracy of leaf NSC estimates at the forest stand level (R2 = 0.49; %RMSE = 9.1%. Spectral analyses indicated strong contributions of the shortwave-IR (1300–2500 nm region to leaf NSC determination at all scales. We conclude that leaf NSC can be remotely sensed, opening doors to monitoring forest canopy physiological responses to environmental stress and climate change.

  20. Using Google Earth to Assess Shade for Sun Protection in Urban Recreation Spaces: Methods and Results.

    Science.gov (United States)

    Gage, R; Wilson, N; Signal, L; Barr, M; Mackay, C; Reeder, A; Thomson, G

    2018-05-16

    Shade in public spaces can lower the risk of and sun burning and skin cancer. However, existing methods of auditing shade require travel between sites, and sunny weather conditions. This study aimed to evaluate the feasibility of free computer software-Google Earth-for assessing shade in urban open spaces. A shade projection method was developed that uses Google Earth street view and aerial images to estimate shade at solar noon on the summer solstice, irrespective of the date of image capture. Three researchers used the method to separately estimate shade cover over pre-defined activity areas in a sample of 45 New Zealand urban open spaces, including 24 playgrounds, 12 beaches and 9 outdoor pools. Outcome measures included method accuracy (assessed by comparison with a subsample of field observations of 10 of the settings) and inter-rater reliability. Of the 164 activity areas identified in the 45 settings, most (83%) had no shade cover. The method identified most activity areas in playgrounds (85%) and beaches (93%) and was accurate for assessing shade over these areas (predictive values of 100%). Only 8% of activity areas at outdoor pools were identified, due to a lack of street view images. Reliability for shade cover estimates was excellent (intraclass correlation coefficient of 0.97, 95% CI 0.97-0.98). Google Earth appears to be a reasonably accurate and reliable and shade audit tool for playgrounds and beaches. The findings are relevant for programmes focused on supporting the development of healthy urban open spaces.

  1. Evaluation of different shades to improve dairy cattle well-being in Argentina

    Science.gov (United States)

    Valtorta, S. E.; Leva, Perla E.; Gallardo, Miriam R.

    Two tree shades (TS1 and TS2) and an artificial shade structure (AS) were evaluated using black globe temperatures (BGTs) to assess their effectiveness in reducing heat load. The artificial structure consisted of a black woven polypropylene cloth providing 80% shade, mounted on 2.5-m-high eucalyptus posts. The work was carried out at Rafaela Experimental Station, Argentina, during the summer (January and February) 1994. BGTs and floor temperatures were measured in concrete floor holding pens with and without artifical shade. The results showed no difference between TS1, TS2 and AS, their average BGTs being 30.2 (SD 0.58), 29.0 (SD 0.70) and 30.2 (SD 0.74)°C, respectively. BGTs under all three shades were significantly lower (Pcows were recorded twice a week. Rectal temperatures were significantly higher for non-shaded cows (Ptree and artificial shades produced similar effects, (2) shading the holding pen with an 80% shading cloth was effective in reducing heat load and floor temperatures, and (3) access to shade in our pasture-based system improved animal well-being.

  2. Assessment of microclimate conditions under artificial shades in a ginseng field.

    Science.gov (United States)

    Lee, Kyu Jong; Lee, Byun-Woo; Kang, Je Yong; Lee, Dong Yun; Jang, Soo Won; Kim, Kwang Soo

    2016-01-01

    Knowledge on microclimate conditions under artificial shades in a ginseng field would facilitate climate-aware management of ginseng production. Weather data were measured under the shade and outside the shade at two fields located in Gochang-gun and Jeongeup-si, Korea, in 2011 and 2012 seasons to assess temperature and humidity conditions under the shade. An empirical approach was developed and validated for the estimation of leaf wetness duration (LWD) using weather measurements outside the shade as inputs to the model. Air temperature and relative humidity were similar between under the shade and outside the shade. For example, temperature conditions favorable for ginseng growth, e.g., between 8°C and 27°C, occurred slightly less frequently in hours during night times under the shade (91%) than outside (92%). Humidity conditions favorable for development of a foliar disease, e.g., relative humidity > 70%, occurred slightly more frequently under the shade (84%) than outside (82%). Effectiveness of correction schemes to an empirical LWD model differed by rainfall conditions for the estimation of LWD under the shade using weather measurements outside the shade as inputs to the model. During dew eligible days, a correction scheme to an empirical LWD model was slightly effective (10%) in reducing estimation errors under the shade. However, another correction approach during rainfall eligible days reduced errors of LWD estimation by 17%. Weather measurements outside the shade and LWD estimates derived from these measurements would be useful as inputs for decision support systems to predict ginseng growth and disease development.

  3. Evaporation from rain-wetted forest in relation to canopy wetness, canopy cover, and net radiation

    NARCIS (Netherlands)

    Klaassen, W.

    2001-01-01

    Evaporation from wet canopies is commonly calculated using E-PM, the Penman-Monteith equation with zero surface resistance. However, several observations show a lower evaporation from rain-wetted forest. Possible causes for the difference between E-PM and experiments are evaluated to provide rules

  4. Towards Tolerance

    NARCIS (Netherlands)

    Lisette Kuyper; Jurjen Iedema; Saskia Keuzenkamp

    2013-01-01

    Across Europe, public attitudes towards lesbian, gay and bisexual (LGB) individuals range from broad tolerance to widespread rejection. Attitudes towards homosexuality are more than mere individual opinions, but form part of the social and political structures which foster or hinder the equality

  5. Intolerant tolerance.

    Science.gov (United States)

    Khushf, G

    1994-04-01

    The Hyde Amendment and Roman Catholic attempts to put restrictions on Title X funding have been criticized for being intolerant. However, such criticism fails to appreciate that there are two competing notions of tolerance, one focusing on the limits of state force and accepting pluralism as unavoidable, and the other focusing on the limits of knowledge and advancing pluralism as a good. These two types of tolerance, illustrated in the writings of John Locke and J.S. Mill, each involve an intolerance. In a pluralistic context where the free exercise of religion is respected, John Locke's account of tolerance is preferable. However, it (in a reconstructed form) leads to a minimal state. Positive entitlements to benefits like artificial contraception or nontherapeutic abortions can legitimately be resisted, because an intolerance has already been shown with respect to those that consider the benefit immoral, since their resources have been coopted by taxation to advance an end that is contrary to their own. There is a sliding scale from tolerance (viewed as forbearance) to the affirmation of communal integrity, and this scale maps on to the continuum from negative to positive rights.

  6. Fluxes of trichloroacetic acid through a conifer forest canopy

    International Nuclear Information System (INIS)

    Stidson, R.T.; Heal, K.V.; Dickey, C.A.; Cape, J.N.; Heal, M.R.

    2004-01-01

    Controlled-dosing experiments with conifer seedlings have demonstrated an above-ground route of uptake for trichloroacetic acid (TCA) from aqueous solution into the canopy, in addition to uptake from the soil. The aim of this work was to investigate the loss of TCA to the canopy in a mature conifer forest exposed only to environmental concentrations of TCA by analysing above- and below-canopy fluxes of TCA and within-canopy instantaneous reservoir of TCA. Concentrations and fluxes of TCA were quantified for one year in dry deposition, rainwater, cloudwater, throughfall, stemflow and litterfall in a 37-year-old Sitka spruce and larch plantation in SW Scotland. Above-canopy TCA deposition was dominated by rainfall (86%), compared with cloudwater (13%) and dry deposition (1%). On average only 66% of the TCA deposition passed through the canopy in throughfall and stemflow (95% and 5%, respectively), compared with 47% of the wet precipitation depth. Consequently, throughfall concentration of TCA was, on average, ∼1.4 x rainwater concentration. There was no significant difference in below-canopy fluxes between Sitka spruce and larch, or at a forest-edge site. Annual TCA deposited from the canopy in litterfall was only ∼1-2% of above-canopy deposition. On average, ∼800 μg m -2 of deposited TCA was lost to the canopy per year, compared with estimates of above-ground TCA storage of ∼400 and ∼300 μg m -2 for Sitka spruce and larch, respectively. Taking into account likely uncertainties in these values (∼±50%), these data yield an estimate for the half-life of within-canopy elimination of TCA in the range 50-200 days, assuming steady-state conditions and that all TCA lost to the canopy is transferred into the canopy material, rather than degraded externally. The observations provide strong indication that an above-ground route is important for uptake of TCA specifically of atmospheric origin into mature forest canopies, as has been shown for seedlings (in

  7. The Importance of Microtopography and Nurse Canopy for Successful Restoration Planting of the Slow-Growing Conifer Pilgerodendron uviferum

    Directory of Open Access Journals (Sweden)

    Jürgen Bauhus

    2013-01-01

    Full Text Available Recent studies have shown that, owing to a lack of seed trees, the natural rate of recovery of fire-disturbed bog forests previously dominated by the endemic and endangered conifer Pilgerodendron uviferum (D. Don Florin is extremely slow. Hence, increasing the number of seed trees in the landscape through restoration planting could remove the principal biotic filter, limiting recovery of these forests. Here, we analyzed how the success of restoration plantings may be improved through the choice or manipulation of microsites in P. uviferum forests on Chiloé Island in North Patagonia. For this purpose, we manipulated microtopography in water-logged sites in bogs (mounds, flat terrain, mineral soil and changed canopy conditions (gaps, semi-open, closed canopy in upland sites with better drainage. In bogs, there was no significant effect of microtopography on growth and survival of P. uviferum plantings. However, fluorescence measurements indicated lower stress in seedlings established on mounds. Seedlings in upland areas established beneath a nurse canopy had lower mortality and higher relative shoot growth, foliar nutrients, photosynthetic light use efficiency and chlorophyll fluorescence values than those planted in the open. This indicates that seedlings of the slow growing P. uviferum can tolerate extremely wet conditions, yet suffer from stress when grown in the open. Here, the removal of canopy appeared to have also removed or reduced mycorrhizal networks for seedlings, leading to poorer nutrition and growth. Based on these results, recommendations for restoration plantings in highly degraded P. uviferum forests are presented.

  8. Effects of shading on dry matter partitioning and yield of field-grown sunflower

    International Nuclear Information System (INIS)

    Villalobos, F.J.; Soriano, A.; Fereres, E.

    1992-01-01

    Crop simulation models require quantitative descriptions of the effects of irradiance on dry matter partition and yield. The objective of this work was to quantify the effects of reduced radiation intensity during different phenological stages on the growth, dry matter partitioning and grain numbers of sunflower (Helianthus annuus, L.). A field experiment was carried out in 1990 with 50 per cent shading treatments. The earliest treatment began at crop emergence while the latest ended at first anthesis. Shading had little effect on plant leaf area growth but reduced biomass and yield. The dry matter: radiation quotient and specific leaf area increased with shading. Grain number per head was decreased by shading, with the greatest effect occurring when shading was applied prior to anthesis. All shading treatments increased dry matter partitioning to stems, decreased assimilate partitioning to the heads and had no effect on the partitioning to leaves. (author)

  9. Effects of shading time on quality of matcha and matcha cake

    Directory of Open Access Journals (Sweden)

    LI Hui

    2014-12-01

    Full Text Available Effects of shading time on the quality of Matcha and the Matcha cake.It showed that shading could help the systhesis of nitrogen compounds such as amino acids,caffeine chlorophyll and protein,but couldn′t favor accumulation of tea polyphenol and polysaccharides.The more shading time was,the more chlorophyll content would be,and the more green of Matcha color would be.After Matcha cake was baked,the green color reduced.The colors of Macha cake are greener with longer shading time.Thus,the length of Shading time has obvious effect on the green tea and the tea cake quality,We can adjust the Matcha cake taste,flavor and color by adding Matcha from different shading time.

  10. Spectral analysis of amazon canopy phenology during the dry season using a tower hyperspectral camera and modis observations

    Science.gov (United States)

    de Moura, Yhasmin Mendes; Galvão, Lênio Soares; Hilker, Thomas; Wu, Jin; Saleska, Scott; do Amaral, Cibele Hummel; Nelson, Bruce Walker; Lopes, Aline Pontes; Wiedeman, Kenia K.; Prohaska, Neill; de Oliveira, Raimundo Cosme; Machado, Carolyne Bueno; Aragão, Luiz E. O. C.

    2017-09-01

    The association between spectral reflectance and canopy processes remains challenging for quantifying large-scale canopy phenological cycles in tropical forests. In this study, we used a tower-mounted hyperspectral camera in an eastern Amazon forest to assess how canopy spectral signals of three species are linked with phenological processes in the 2012 dry season. We explored different approaches to disentangle the spectral components of canopy phenology processes and analyze their variations over time using 17 images acquired by the camera. The methods included linear spectral mixture analysis (SMA); principal component analysis (PCA); continuum removal (CR); and first-order derivative analysis. In addition, three vegetation indices potentially sensitive to leaf flushing, leaf loss and leaf area index (LAI) were calculated: the Enhanced Vegetation Index (EVI), Normalized Difference Vegetation Index (NDVI) and the entitled Green-Red Normalized Difference (GRND) index. We inspected also the consistency of the camera observations using Moderate Resolution Imaging Spectroradiometer (MODIS) and available phenological data on new leaf production and LAI of young, mature and old leaves simulated by a leaf demography-ontogeny model. The results showed a diversity of phenological responses during the 2012 dry season with related changes in canopy structure and greenness values. Because of the differences in timing and intensity of leaf flushing and leaf shedding, Erisma uncinatum, Manilkara huberi and Chamaecrista xinguensis presented different green vegetation (GV) and non-photosynthetic vegetation (NPV) SMA fractions; distinct PCA scores; changes in depth, width and area of the 681-nm chlorophyll absorption band; and variations over time in the EVI, GRND and NDVI. At the end of dry season, GV increased for Erisma uncinatum, while NPV increased for Chamaecrista xinguensis. For Manilkara huberi, the NPV first increased in the beginning of August and then decreased toward

  11. Experimental and Simulation for the Effect of Partial Shading on Solar Panel Performance

    Directory of Open Access Journals (Sweden)

    Emad Talib Hahsim

    2016-06-01

    Full Text Available Partial shading is one of the problems that affects the power production and the efficiency of photovoltaic module. A series of experimental work have been done of partial shading of monocrystalline PV module; 50W, Isc: 3.1A, Voc: 22V with 36 cells in series is achieved. Non-linear power output responses of the module are observed by applying various cases of partial shading (vertical and horizontal shading of solar cells in the module. Shading a single cell (corner cell has the greatest impact on output energy. Horizontal shading or vertical shading reduced the power from 41W to 18W at constant solar radiation 1000W/m2 and steady state condition. Vertical blocking a column of cells (9 cells in a module reduces the power from 41W to 18W (53% power reduction; while, blocking one or two cell in the row reduces the power from 41 W to 18W (53% power reduction. Shading three or four cells in the same row reduces the power from 41W to 1W or 0.006W (94% power reduction. A complete Matlab / Simulink model are achieved to simulate the effect of partial shading on power output of module. It is found that shading a single cell reduces the power from 50 W to 25 W (50% using Matlab/Simulink model. Comparisons have been made between the I-V and P-V characteristic curves from the simulation with the practical (experimental curves. The results showed that the percentage of error between the Simulink results and the corresponding experimental measurement are 22% without shading effect and, 32% with partial shading.

  12. Satisfaction of Dental Students, Faculty, and Patients with Tooth Shade-Matching Using a Spectrophotometer.

    Science.gov (United States)

    Ballard, Erin; Metz, Michael J; Harris, Bryan T; Metz, Cynthia J; Chou, Jang-Ching; Morton, Dean; Lin, Wei-Shao

    2017-05-01

    The aims of this study were to evaluate dental students' clinical shade-matching outcomes (from subjective use of shade guide) with an objective electronic shade-matching tool (spectrophotometer); to assess patients', students', and supervising faculty members' satisfaction with the clinical shade-matching outcomes; and to assess clinicians' support for use of the spectrophotometer to improve esthetic outcomes. A total of 103 volunteer groups, each consisting of patient, dental student, and supervising faculty member at the University of Louisville, were recruited to participate in the study in 2015. Using the spectrophotometer, clinical shade-matching outcome (ΔE clinical ) and laboratory shade-matching outcome (ΔE laboratory ) were calculated. Two five-point survey items were used to assess the groups' satisfaction with the clinical shade-matching outcome and support for an objective electronic shade-matching tool in the student clinic. The results showed that both ΔE clinical (6.5±2.4) and ΔE laboratory (4.3±2.0) were outside the clinical acceptability threshold ΔE values of 2.7, when visual shade-matching method (subjective usage of shade guide) was used to fabricate definitive restorations. Characteristics of the patients, dental students, supervising faculty members, and restorations had minimal to no effect on the ΔE clinical The patients, dental students, and supervising faculty members generally had positive opinions about the clinical shade-matching outcome, despite the increased ΔE clinical observed. Overall, clinical shade-matching outcomes in this school need further improvement, but the patients' positive opinions may indicate the need to revisit the acceptability threshold ΔE value of 2.7 in the academic setting.

  13. Effects of shade on growth, production and quality of coffee (Coffea arabica) in Ethiopia

    OpenAIRE

    Bote, A.D.; Struik, P.C.

    2011-01-01

    The research work was conducted to evaluate the effect of shade on growth and production of coffee plants. To achieve this, growth and productivity of coffee plants growing under shade trees were compared with those of coffee plants growing under direct sun light. Different physiological, environmental and quality parameters were assessed for both treatments. Shade trees protected coffee plants against adverse environmental stresses such as high soil temperatures and low relative humidity. Sh...

  14. Experimental study of the effect of fully shading on the Solar PV module performance

    Science.gov (United States)

    Al-chaderchi, Monadhil; Sopain, K.; Alghoul, M. A.; Salameh, T.

    2017-11-01

    Experimental tests were performed to study the effects of shading for different string inside the photovoltaic (PV) panels, power equipped with different number of diodes from the same manufacturer as of solar panel. The IV curve for all cases were recorded to see how the bypass diodes will reduce the effects of shading .The case for 3 by pass diode show the best performance of solar PV module under shading phenomena.

  15. VALIDATING the Accuracy of Sighten's Automated Shading Tool

    Energy Technology Data Exchange (ETDEWEB)

    2018-05-04

    Solar companies - including installers, financiers, and distributors - leverage Sighten software to deliver accurate shading calculations and solar proposals. Sighten recently partnered with Google Project Sunroof to provide automated remote shading analysis directly within the Sighten platform. The National Renewable Energy Laboratory (NREL), in partnership with Sighten, independently verified the accuracy of Sighten's remote-shading solar access values (SAVs) on an annual basis for locations in Los Angeles, California, and Denver, Colorado.

  16. Biodiversity Meets the Atmosphere: A Global View of Forest Canopies

    Science.gov (United States)

    C. M. P. Ozanne; D. Anhuf; S. L. Boulter; M. Keller; R. L. Kitching; C. Korner; F. C. Meinzer; A. W. Mitchell; T. Nakashizuka; P. L. Silva Dias; N. E. Stork; S. J. Wright; M Yoshimura

    2003-01-01

    The forest canopy is the functional interface between 90% of Earth’s terrestrial biomass and the atmosphere. Multidisciplinary research in the canopy has expanded concepts of global species richness, physiological processes, and the provision of ecosystem services. Trees respond in a species-specific manner to elevated carbon dioxide levels, while climate change...

  17. Water stress effects on spatially referenced cotton crop canopy properties

    Science.gov (United States)

    rop canopy temperature is known to be affected by water stress. Canopy reflectance can also be impacted as leaf orientation and color respond to the stress. As sensor systems are investigated for real-time management of irrigation and nitrogen, it is essential to understand how the data from the sen...

  18. Hierarchical Canopy Dynamics of Electrolyte-Doped Nanoscale Ionic Materials

    KAUST Repository

    Jespersen, Michael L.

    2013-12-23

    Nanoscale ionic materials (NIMs) are organic-inorganic hybrids prepared from ionically functionalized nanoparticles (NP) neutralized by oligomeric polymer counterions. NIMs are designed to behave as liquids under ambient conditions in the absence of solvent and have no volatile organic content, making them useful for a number of applications. We have used nuclear magnetic resonance relaxation and pulsed-field gradient NMR to probe local and collective canopy dynamics in NIMs based on 18-nm silica NPs with a covalently bound anionic corona, neutralized by amine-terminated ethylene oxide/propylene oxide block copolymers. The NMR relaxation studies show that the nanosecond-scale canopy dynamics depend on the degree of neutralization, the canopy radius of gyration, and crowding at the ionically modified NP surface. Two canopy populations are observed in the diffusion experiments, demonstrating that one fraction of the canopy is bound to the NP surface on the time scale (milliseconds) of the diffusion experiment and is surrounded by a more mobile layer of canopy that is unable to access the surface due to molecular crowding. The introduction of electrolyte ions (Na+ or Mg2+) screens the canopy-corona electrostatic interactions, resulting in a reduced bulk viscosity and faster canopy exchange. The magnitude of the screening effect depends upon ion concentration and valence, providing a simple route for tuning the macroscopic properties of NIMs. © 2013 American Chemical Society.

  19. Hierarchical Canopy Dynamics of Electrolyte-Doped Nanoscale Ionic Materials

    KAUST Repository

    Jespersen, Michael L.; Mirau, Peter A.; von Meerwall, Ernst D.; Koerner, Hilmar; Vaia, Richard A.; Fernandes, Nikhil J.; Giannelis, Emmanuel P.

    2013-01-01

    Nanoscale ionic materials (NIMs) are organic-inorganic hybrids prepared from ionically functionalized nanoparticles (NP) neutralized by oligomeric polymer counterions. NIMs are designed to behave as liquids under ambient conditions in the absence of solvent and have no volatile organic content, making them useful for a number of applications. We have used nuclear magnetic resonance relaxation and pulsed-field gradient NMR to probe local and collective canopy dynamics in NIMs based on 18-nm silica NPs with a covalently bound anionic corona, neutralized by amine-terminated ethylene oxide/propylene oxide block copolymers. The NMR relaxation studies show that the nanosecond-scale canopy dynamics depend on the degree of neutralization, the canopy radius of gyration, and crowding at the ionically modified NP surface. Two canopy populations are observed in the diffusion experiments, demonstrating that one fraction of the canopy is bound to the NP surface on the time scale (milliseconds) of the diffusion experiment and is surrounded by a more mobile layer of canopy that is unable to access the surface due to molecular crowding. The introduction of electrolyte ions (Na+ or Mg2+) screens the canopy-corona electrostatic interactions, resulting in a reduced bulk viscosity and faster canopy exchange. The magnitude of the screening effect depends upon ion concentration and valence, providing a simple route for tuning the macroscopic properties of NIMs. © 2013 American Chemical Society.

  20. Forest canopy BRDF simulation using Monte Carlo method

    NARCIS (Netherlands)

    Huang, J.; Wu, B.; Zeng, Y.; Tian, Y.

    2006-01-01

    Monte Carlo method is a random statistic method, which has been widely used to simulate the Bidirectional Reflectance Distribution Function (BRDF) of vegetation canopy in the field of visible remote sensing. The random process between photons and forest canopy was designed using Monte Carlo method.

  1. Soil carbon estimation from eucalyptus grandis using canopy spectra

    African Journals Online (AJOL)

    Mapping soil fertility parameters, such as soil carbon (C), is fundamentally important for forest management and research related to forest growth and climate change. This study seeks to establish the link between Eucalyptus grandis canopy spectra and soil carbon using raw and continuum-removed spectra. Canopy-level ...

  2. Crop canopy BRDF simulation and analysis using Monte Carlo method

    NARCIS (Netherlands)

    Huang, J.; Wu, B.; Tian, Y.; Zeng, Y.

    2006-01-01

    This author designs the random process between photons and crop canopy. A Monte Carlo model has been developed to simulate the Bi-directional Reflectance Distribution Function (BRDF) of crop canopy. Comparing Monte Carlo model to MCRM model, this paper analyzes the variations of different LAD and

  3. Estimating wood volume from canopy area in deciduous woodlands ...

    African Journals Online (AJOL)

    In this study we tested the predictive ability of canopy area in estimating wood volume in deciduous woodlands of Zimbabwe. The study was carried out in four sites of different climatic conditions. We used regression analysis to statistically quantify the prediction of wood volume from canopy area at species and stand level ...

  4. Salt Tolerance

    OpenAIRE

    Xiong, Liming; Zhu, Jian-Kang

    2002-01-01

    Studying salt stress is an important means to the understanding of plant ion homeostasis and osmo-balance. Salt stress research also benefits agriculture because soil salinity significantly limits plant productivity on agricultural lands. Decades of physiological and molecular studies have generated a large body of literature regarding potential salt tolerance determinants. Recent advances in applying molecular genetic analysis and genomics tools in the model plant Arabidopsis thaliana are sh...

  5. Dental Shade Guide Variability for Hues B, C, and D Using Cross-Polarized Photography.

    Science.gov (United States)

    Sampaio, Camila S; Gurrea, Jon; Gurrea, Marta; Bruguera, August; Atria, Pablo J; Janal, Malvin; Bonfante, Estevam A; Coelho, Paulo G; Hirata, Ronaldo

    2018-04-20

    This study evaluated the color variability of hues B, C, and D between the VITA Classical shade guide (Vita Zahnfabrik) and four other VITA-coded ceramic shade guides using a digital camera (Canon EOS 60D) and computer software (Adobe Photoshop CC). A cross-polarizing filter was used to standardize external light sources influencing color match. A total of 275 pictures were taken, 5 per shade tab, for 11 shades (B1, B2, B3, B4, C1, C2, C3, C4, D2, D3, and D4), from the following shade guides: VITA Classical (control); IPS e.max Ceram (Ivoclar Vivadent); IPS d.SIGN (Ivoclar Vivadent); Initial ZI (GC); and Creation CC (Creation Willi Geller). Pictures were evaluated using Adobe Photoshop CC for standardization of hue, chroma, and value between shade tabs. The VITA-coded shade guides evaluated here showed an overall unmatched shade in all their tabs when compared to the control, suggesting that shade selection should be made with the corresponding manufacturer guide of the ceramic intended for the final restoration.

  6. Daylighting performance evaluation of a bottom-up motorized roller shade

    Energy Technology Data Exchange (ETDEWEB)

    Kapsis, K.; Athienitis, A.K.; Zmeureanu, R.G. [Department of Building, Civil and Environmental Engineering, Concordia University, Montreal, QC (Canada); Tzempelikos, A. [School of Civil Engineering, Purdue University, West Lafayette, IN (United States)

    2010-12-15

    This paper presents an experimental and simulation study for quantifying the daylighting performance of bottom-up roller shades installed in office spaces. The bottom-up shade is a motorized roller shade that opens from top to bottom operating in the opposite direction of a conventional roller shade, so as to cover the bottom part of the window, while allowing daylight to enter from the top part of the window, reaching deeper into the room. A daylighting simulation model, validated with full-scale experiments, was developed in order to establish correlations between the shade position, outdoor illuminance and work plane illuminance for different outdoor conditions. Then, a shading control algorithm was developed for application in any location and orientation. The validated model was employed for a sensitivity analysis of the impact of shade optical properties and control on the potential energy savings due to the use of daylighting. The results showed that Daylight Autonomy for the bottom-up shade is 8-58% higher compared to a conventional roller shade, with a difference of 46% further away from the facade, where the use of electric lighting is needed most of the time. The potential reduction in energy consumption for lighting is 21-41%. (author)

  7. Partial Shade Evaluation of Distributed Power Electronics for Photovoltaic Systems: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Deline, C.; Meydbrav, J.; Donovan, M.

    2012-06-01

    Site survey data for several residential installations are provided, showing the extent and frequency of shade throughout the year. This background information is used to design a representative shading test that is conducted on two side-by-side 8-kW photovoltaic (PV) installations. One system is equipped with a standard string inverter, while the other is equipped with microinverters on each solar panel. Partial shade is applied to both systems in a comprehensive range of shading conditions, simulating one of three shade extents. Under light shading conditions, the microinverter system produced the equivalent of 4% annual performance improvement, relative to the string inverter system. Under moderate shading conditions, the microinverter system outperformed the string inverter system by 8%, and under heavy shading the microinverter increased relative performance by 12%. In all three cases, the percentage of performance loss that is recovered by the use of distributed power electronics is 40%-50%. Additionally, it was found that certain shading conditions can lead to additional losses in string inverters due to peak-power tracking errors and voltage limitations.

  8. A meta-analysis of responses of canopy photosynthetic conversion efficiency to environmental factors reveals major causes of yield gap

    Science.gov (United States)

    Slattery, Rebecca A.; Ainsworth, Elizabeth A.; Ort, Donald R.

    2013-01-01

    Improving plant energy conversion efficiency (εc) is crucial for increasing food and bioenergy crop production and yields. Using a meta-analysis, the effects of greenhouse gases, weather-related stresses projected to intensify due to climate change, and management practices including inputs, shading, and intercropping on εc were statistically quantified from 140 published studies to identify where improvements would have the largest impact on closing yield gaps. Variation in the response of εc to treatment type and dosage, plant characteristics, and growth conditions were also examined. Significant mean increases in εc were caused by elevated [CO2] (20%), shade (18%), and intercropping (15%). εc increased curvilinearly up to 55% with nitrogen additions whereas phosphorus application was most beneficial at low levels. Significant decreases in εc of –8.4% due to elevated [O3], –16.8% due to water stress, and –6.5% due to foliar damage were found. A non-significant decrease in εc of –17.3% was caused by temperature stress. These results identify the need to engineer greater stress tolerance and enhanced responses to positive factors such as [CO2] and nitrogen to improve average yields and yield potential. Optimizing management strategies will also enhance the benefits possible with intercropping, shade, and pest resilience. To determine optimal practices for εc improvement, further studies should be conducted in the field since several responses were exaggerated by non-field experimental conditions. PMID:23873996

  9. Measuring canopy structure with an airborne laser altimeter

    International Nuclear Information System (INIS)

    Ritchie, J.C.; Evans, D.L.; Jacobs, D.; Everitt, J.H.; Weltz, M.A.

    1993-01-01

    Quantification of vegetation patterns and properties is needed to determine their role on the landscape and to develop management plans to conserve our natural resources. Quantifying vegetation patterns from the ground, or by using aerial photography or satellite imagery is difficult, time consuming, and often expensive. Digital data from an airborne laser altimeter offer an alternative method to quantify selected vegetation properties and patterns of forest and range vegetation. Airborne laser data found canopy heights varied from 2 to 6 m within even-aged pine forests. Maximum canopy heights measured with the laser altimeter were significantly correlated to measurements made with ground-based methods. Canopy shape could be used to distinguish deciduous and evergreen trees. In rangeland areas, vegetation heights, spatial patterns, and canopy cover measured with the laser altimeter were significantly related with field measurements. These studies demonstrate the potential of airborne laser data to measure canopy structure and properties for large areas quickly and quantitatively

  10. Thermal IR exitance model of a plant canopy

    Science.gov (United States)

    Kimes, D. S.; Smith, J. A.; Link, L. E.

    1981-01-01

    A thermal IR exitance model of a plant canopy based on a mathematical abstraction of three horizontal layers of vegetation was developed. Canopy geometry within each layer is quantitatively described by the foliage and branch orientation distributions and number density. Given this geometric information for each layer and the driving meteorological variables, a system of energy budget equations was determined and solved for average layer temperatures. These estimated layer temperatures, together with the angular distributions of radiating elements, were used to calculate the emitted thermal IR radiation as a function of view angle above the canopy. The model was applied to a lodgepole pine (Pinus contorta) canopy over a diurnal cycle. Simulated vs measured radiometric average temperatures of the midcanopy layer corresponded with 2 C. Simulation results suggested that canopy geometry can significantly influence the effective radiant temperature recorded at varying sensor view angles.

  11. Canopy profiles of photosynthetic parameters under elevated CO2 and N fertilization in a poplar plantation

    International Nuclear Information System (INIS)

    Calfapietra, Carlo; Tulva, Ingmar; Eensalu, Eve; Perez, Marta; De Angelis, Paolo; Scarascia-Mugnozza, Giuseppe; Kull, Olevi

    2005-01-01

    A poplar plantation has been exposed to an elevated CO 2 concentration for 5 years using the free air CO 2 enrichment (FACE) technique. Even after such a long period of exposure, leaves of Populus x euramericana have not shown clear signs of photosynthetic acclimation. Only at the end of the growing season for shade leaves was a decrease of maximum velocity of carboxylation (V cmax ) observed. Maximum electron transport rate (J max ) was increased by FACE treatment in July. Assimilation rates at CO 2 partial pressure of 400 (A 400 ) and 600 (A 600 ) μmol mol -1 were not significantly different under FACE treatment. Most notably FACE significantly decreased stomatal conductance (g s ) both on upper and lower canopy leaves. N fertilization increased N content in the leaves on mass basis (N m ) and specific leaf area (SLA) in both CO 2 treatments but did not influence the photosynthetic parameters. These data show that in poplar plantations the long-term effects of elevated CO 2 on photosynthesis do not differ considerably from the short-term ones even with N deposition. - Photosynthetic acclimation occurred only marginally

  12. Fifty Shades: ambivalence about birth control in an erotic bestseller and its cultural implications.

    Science.gov (United States)

    Maierhofer, Waltraud; Israel, Emanuella

    2017-04-01

    The Fifty Shades trilogy by E.L. James has taken the world by storm and become a cultural phenomenon. The lack of contraceptive use in the erotic fiction, first pointed out by bloggers, is analysed in this article and compared to medical information. James may be praised for sexualising condom use. However, her protagonist makes poor choices in terms of hormonal contraception and is negligent about its use, resulting in an unintended pregnancy and resolved in marital bliss and motherhood. What is of more interest here than a possible message about contraceptive use, is the outcome that the fiction's negligence in birth control and responsibility affirms an ideology in which female sexuality and sexual experimentation can only be tolerated within the context of procreation and affirmation of motherhood. Subsequently, the cultural significance of the trilogy's popularity and its tension between sexual exploration, birth control and fertility is explored. In a globally popular fantasy published more than five decades after the introduction of the pill, the protagonist's lack of attention to reliable birth control leads to a telling dichotomy that combines adventurous exploration of female sexuality and affirmation of the nuclear family.

  13. Repeated Thermal Stress, Shading, and Directional Selection in the Florida Reef Tract

    Directory of Open Access Journals (Sweden)

    Robert van Woesik

    2017-06-01

    Full Text Available Over the last three decades reef corals have been subjected to an unprecedented frequency and intensity of thermal-stress events, which have led to extensive coral bleaching, disease, and mortality. Over the next century, the climate is predicted to drive sea-surface temperatures to even higher levels, consequently increasing the risk of mass bleaching and disease outbreaks. Yet, there is considerable temporal and spatial variation in coral bleaching and in disease prevalence. Using data collected from 2,398 sites along the Florida reef tract from 2005 to 2015, this study examined the temporal and spatial patterns of coral bleaching and disease in relation to coral-colony size, depth, temperature, and chlorophyll-a concentrations. The results show that coral bleaching was most prevalent during the warmest years in 2014 and 2015, and disease was also most prevalent in 2010, 2014, and 2015. Although the majority of the corals surveyed were found in habitats with low chlorophyll-a concentrations, and high irradiance, these same habitats showed the highest prevalence of coral bleaching and disease outbreaks during thermal-stress events. These results suggest that directional selection in a warming ocean may favor corals able to tolerate inshore, shaded environments with high turbidity and productivity.

  14. Deploying Fourier Coefficients to Unravel Soybean Canopy Diversity.

    Science.gov (United States)

    Jubery, Talukder Z; Shook, Johnathon; Parmley, Kyle; Zhang, Jiaoping; Naik, Hsiang S; Higgins, Race; Sarkar, Soumik; Singh, Arti; Singh, Asheesh K; Ganapathysubramanian, Baskar

    2016-01-01

    Soybean canopy outline is an important trait used to understand light interception ability, canopy closure rates, row spacing response, which in turn affects crop growth and yield, and directly impacts weed species germination and emergence. In this manuscript, we utilize a methodology that constructs geometric measures of the soybean canopy outline from digital images of canopies, allowing visualization of the genetic diversity as well as a rigorous quantification of shape parameters. Our choice of data analysis approach is partially dictated by the need to efficiently store and analyze large datasets, especially in the context of planned high-throughput phenotyping experiments to capture time evolution of canopy outline which will produce very large datasets. Using the Elliptical Fourier Transformation (EFT) and Fourier Descriptors (EFD), canopy outlines of 446 soybean plant introduction (PI) lines from 25 different countries exhibiting a wide variety of maturity, seed weight, and stem termination were investigated in a field experiment planted as a randomized complete block design with up to four replications. Canopy outlines were extracted from digital images, and subsequently chain coded, and expanded into a shape spectrum by obtaining the Fourier coefficients/descriptors. These coefficients successfully reconstruct the canopy outline, and were used to measure traditional morphometric traits. Highest phenotypic diversity was observed for roundness, while solidity showed the lowest diversity across all countries. Some PI lines had extraordinary shape diversity in solidity. For interpretation and visualization of the complexity in shape, Principal Component Analysis (PCA) was performed on the EFD. PI lines were grouped in terms of origins, maturity index, seed weight, and stem termination index. No significant pattern or similarity was observed among the groups; although interestingly when genetic marker data was used for the PCA, patterns similar to canopy

  15. The impact of modifying photosystem antenna size on canopy photosynthetic efficiency-Development of a new canopy photosynthesis model scaling from metabolism to canopy level processes.

    Science.gov (United States)

    Song, Qingfeng; Wang, Yu; Qu, Mingnan; Ort, Donald R; Zhu, Xin-Guang

    2017-12-01

    Canopy photosynthesis (A c ) describes photosynthesis of an entire crop field and the daily and seasonal integrals of A c positively correlate with daily and seasonal biomass production. Much effort in crop breeding has focused on improving canopy architecture and hence light distribution inside the canopy. Here, we develop a new integrated canopy photosynthesis model including canopy architecture, a ray tracing algorithm, and C 3 photosynthetic metabolism to explore the option of manipulating leaf chlorophyll concentration ([Chl]) for greater A c and nitrogen use efficiency (NUE). Model simulation results show that (a) efficiency of photosystem II increased when [Chl] was decreased by decreasing antenna size and (b) the light received by leaves at the bottom layers increased when [Chl] throughout the canopy was decreased. Furthermore, the modelling revealed a modest ~3% increase in A c and an ~14% in NUE was accompanied when [Chl] reduced by 60%. However, if the leaf nitrogen conserved by this decrease in leaf [Chl] were to be optimally allocated to other components of photosynthesis, both A c and NUE can be increased by over 30%. Optimizing [Chl] coupled with strategic reinvestment of conserved nitrogen is shown to have the potential to support substantial increases in A c , biomass production, and crop yields. © 2017 The Authors Plant, Cell & Environment Published by John Wiley & Sons Ltd.

  16. Momentum and scalar transport within a vegetation canopy following atmospheric stability and seasonal canopy changes: the CHATS experiment

    Directory of Open Access Journals (Sweden)

    S. Dupont

    2012-07-01

    Full Text Available Momentum and scalar (heat and water vapor transfer between a walnut canopy and the overlying atmosphere are investigated for two seasonal periods (before and after leaf-out, and for five thermal stability regimes (free and forced convection, near-neutral condition, transition to stable, and stable. Quadrant and octant analyses of momentum and scalar fluxes followed by space-time autocorrelations of observations from the Canopy Horizontal Array Turbulence Study's (CHATS thirty meter tower help characterize the motions exchanging momentum, heat, and moisture between the canopy layers and aloft.

    During sufficiently windy conditions, i.e. in forced convection, near-neutral and transition to stable regimes, momentum and scalars are generally transported by sweep and ejection motions associated with the well-known canopy-top "shear-driven" coherent eddy structures. During extreme stability conditions (both unstable and stable, the role of these "shear-driven" structures in transporting scalars decreases, inducing notable dissimilarity between momentum and scalar transport.

    In unstable conditions, "shear-driven" coherent structures are progressively replaced by "buo-yantly-driven" structures, known as thermal plumes; which appear very efficient at transporting scalars, especially upward thermal plumes above the canopy. Within the canopy, downward thermal plumes become more efficient at transporting scalars than upward thermal plumes if scalar sources are located in the upper canopy. We explain these features by suggesting that: (i downward plumes within the canopy correspond to large downward plumes coming from above, and (ii upward plumes within the canopy are local small plumes induced by canopy heat sources where passive scalars are first injected if there sources are at the same location as heat sources. Above the canopy, these small upward thermal plumes aggregate to form larger scale upward thermal plumes. Furthermore, scalar

  17. Identity and diversity of coral endosymbionts (zooxanthellae) from three Palauan reefs with contrasting bleaching, temperature and shading histories.

    Science.gov (United States)

    Fabricius, K E; Mieog, J C; Colin, P L; Idip, D; van Oppen, M J H

    2004-08-01

    The potential of corals to associate with more temperature-tolerant strains of algae (zooxanthellae, Symbiodinium) can have important implications for the future of coral reefs in an era of global climate change. In this study, the genetic identity and diversity of zooxanthellae was investigated at three reefs with contrasting histories of bleaching mortality, water temperature and shading, in the Republic of Palau (Micronesia). Single-stranded conformation polymorphism and sequence analysis of the ribosomal DNA internal transcribed spacer (ITS)1 region was used for genotyping. A chronically warm but partly shaded coral reef in a marine lake that is hydrographically well connected to the surrounding waters harboured only two single-stranded conformation polymorphism profiles (i.e. zooxanthella communities). It consisted only of Symbiodinium D in all 13 nonporitid species and two Porites species investigated, with the remaining five Porites harbouring C*. Despite the high temperature in this lake (> 0.5 degrees above ambient), this reef did not suffer coral mortality during the (1998) bleaching event, however, no bleaching-sensitive coral families and genera occur in the coral community. This setting contrasts strongly with two other reefs with generally lower temperatures, in which 10 and 12 zooxanthella communities with moderate to low proportions of clade D zooxanthellae were found. The data indicate that whole coral assemblages, when growing in elevated seawater temperatures and at reduced irradiance, can be composed of colonies associated with the more thermo-tolerant clade D zooxanthellae. Future increases in seawater temperature might, therefore, result in an increasing prevalence of Symbiodinium phylotype D in scleractinian corals, possibly associated with a loss of diversity in both zooxanthellae and corals. Copyright 2004 Blackwell Publishing Ltd

  18. Forest canopy temperatures: dynamics, controls, and relationships with ecosystem fluxes

    Science.gov (United States)

    Still, C. J.; Griffith, D.; Kim, Y.; Law, B. E.; Hanson, C. V.; Kwon, H.; Schulze, M.; Detto, M.; Pau, S.

    2017-12-01

    Temperature strongly affects enzymatic reactions, ecosystem biogeochemistry, and species distributions. Although most focus is on air temperature, the radiative or skin temperature of plants is more relevant. Canopy skin temperature dynamics reflect biophysical, physiological, and anatomical characteristics and interactions with the environment, and can be used to examine forest responses to stresses like droughts and heat waves. Thermal infrared (TIR) imaging allows for extensive temporal and spatial sampling of canopy temperatures, particularly compared to spot measurements using thermocouples. We present results of TIR imaging of forest canopies at eddy covariance flux tower sites in the US Pacific Northwest and in Panama. These forests range from an old-growth temperate rainforest to a second growth semi-arid pine forest to a semi-deciduous tropical forest. Canopy temperature regimes at these sites are highly variable. Canopy temperatures at all forest sites displayed frequent departures from air temperature, particularly during clear sky conditions, with elevated canopy temperatures during the day and depressed canopy temperatures at night compared to air temperature. Comparison of canopy temperatures to fluxes of carbon dioxide, water vapor, and energy reveals stronger relationships than those found with air temperature. Daytime growing season net ecosystem exchange at the pine forest site is better explained by canopy temperature (r2 = 0.61) than air temperature (r2 = 0.52). At the semi-deciduous tropical forest, canopy photosynthesis is highly correlated with canopy temperature (r2 = 0.51), with a distinct optimum temperature for photosynthesis ( 31 °C) that agrees with leaf-level measurements. During the peak of one heat wave at an old-growth temperate rainforest, hourly averaged air temperature exceeded 35 °C, 10 °C above average. Peak hourly canopy temperature approached 40 °C, and leaf-to-air vapor pressure deficit exceeded 6 kPa. These extreme

  19. Canopy wake measurements using multiple scanning wind LiDARs

    Science.gov (United States)

    Markfort, C. D.; Carbajo Fuertes, F.; Iungo, V.; Stefan, H. G.; Porte-Agel, F.

    2014-12-01

    Canopy wakes have been shown, in controlled wind tunnel experiments, to significantly affect the fluxes of momentum, heat and other scalars at the land and water surface over distances of ˜O(1 km), see Markfort et al. (EFM, 2013). However, there are currently no measurements of the velocity field downwind of a full-scale forest canopy. Point-based anemometer measurements of wake turbulence provide limited insight into the extent and details of the wake structure, whereas scanning Doppler wind LiDARs can provide information on how the wake evolves in space and varies over time. For the first time, we present measurements of the velocity field in the wake of a tall patch of forest canopy. The patch consists of two uniform rows of 40-meter tall deciduous, plane trees, which border either side of the Allée de Dorigny, near the EPFL campus. The canopy is approximately 250 m long, and it is approximately 40 m wide, along the direction of the wind. A challenge faced while making field measurements is that the wind rarely intersects a canopy normal to the edge. The resulting wake flow may be deflected relative to the mean inflow. Using multiple LiDARs, we measure the evolution of the wake due to an oblique wind blowing over the canopy. One LiDAR is positioned directly downwind of the canopy to measure the flow along the mean wind direction and the other is positioned near the canopy to evaluate the transversal component of the wind and how it varies with downwind distance from the canopy. Preliminary results show that the open trunk space near the base of the canopy results in a surface jet that can be detected just downwind of the canopy and farther downwind dissipates as it mixes with the wake flow above. A time-varying recirculation zone can be detected by the periodic reversal of the velocity near the surface, downwind of the canopy. The implications of canopy wakes for measurement and modeling of surface fluxes will be discussed.

  20. Evaluation of Cellular Shades in the PNNL Lab Homes

    Energy Technology Data Exchange (ETDEWEB)

    Petersen, Joseph M. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Sullivan, Greg [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Cort, Katherine A. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Metzger, Cheryn E. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Merzouk, Massine [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2016-11-01

    This report examines the energy performance of cellular shade window coverings in a matched pair of all-electric, factory-built “Lab Homes” located on the Pacific Northwest National Laboratory (PNNL) campus in Richland, Washington. The 1500-square-foot homes were identical in construction and baseline performance, which allowed any difference in energy and thermal performance between the baseline home and the experimental home to be attributed to the retrofit technology installed in the experimental home. To assess the performance of high efficiency window attachments in a residential retrofit application, the building shell air leakage, energy use, and interior temperatures of each home were compared during the 2015 -2016 winter heating and summer cooling seasons. Hunter Douglas Duette® Architella® Trielle™ opaque honeycomb “cellular” shades were installed over double-pane clear-glass, aluminum-frame primary windows in the experimental home and were compared to identical primary windows with no window coverings and with standard typical white vinyl horizontal blind window coverings in the baseline home.

  1. Maximum power point tracking of partially shaded solar photovoltaic arrays

    Energy Technology Data Exchange (ETDEWEB)

    Roy Chowdhury, Shubhajit; Saha, Hiranmay [IC Design and Fabrication Centre, Department of Electronics and Telecommunication Engineering, Jadavpur University (India)

    2010-09-15

    The paper presents the simulation and hardware implementation of maximum power point (MPP) tracking of a partially shaded solar photovoltaic (PV) array using a variant of Particle Swarm Optimization known as Adaptive Perceptive Particle Swarm Optimization (APPSO). Under partially shaded conditions, the photovoltaic (PV) array characteristics get more complex with multiple maxima in the power-voltage characteristic. The paper presents an algorithmic technique to accurately track the maximum power point (MPP) of a PV array using an APPSO. The APPSO algorithm has also been validated in the current work. The proposed technique uses only one pair of sensors to control multiple PV arrays. This result in lower cost and higher accuracy of 97.7% compared to earlier obtained accuracy of 96.41% using Particle Swarm Optimization. The proposed tracking technique has been mapped onto a MSP430FG4618 microcontroller for tracking and control purposes. The whole system based on the proposed has been realized on a standard two stage power electronic system configuration. (author)

  2. Infectious Tolerance

    OpenAIRE

    Jonuleit, Helmut; Schmitt, Edgar; Kakirman, Hacer; Stassen, Michael; Knop, Jürgen; Enk, Alexander H.

    2002-01-01

    Regulatory CD4+CD25+ T cells (Treg) are mandatory for maintaining immunologic self-tolerance. We demonstrate that the cell-cell contact–mediated suppression of conventional CD4+ T cells by human CD25+ Treg cells is fixation resistant, independent from membrane-bound TGF-β but requires activation and protein synthesis of CD25+ Treg cells. Coactivation of CD25+ Treg cells with Treg cell–depleted CD4+ T cells results in anergized CD4+ T cells that in turn inhibit the activation of conventional, ...

  3. A radiosity model for heterogeneous canopies in remote sensing

    Science.gov (United States)

    GarcíA-Haro, F. J.; Gilabert, M. A.; Meliá, J.

    1999-05-01

    A radiosity model has been developed to compute bidirectional reflectance from a heterogeneous canopy approximated by an arbitrary configuration of plants or clumps of vegetation, placed on the ground surface in a prescribed manner. Plants are treated as porous cylinders formed by aggregations of layers of leaves. This model explicitly computes solar radiation leaving each individual surface, taking into account multiple scattering processes between leaves and soil, and occlusion of neighboring plants. Canopy structural parameters adopted in this study have served to simplify the computation of the geometric factors of the radiosity equation, and thus this model has enabled us to simulate multispectral images of vegetation scenes. Simulated images have shown to be valuable approximations of satellite data, and then a sensitivity analysis to the dominant parameters of discontinuous canopies (plant density, leaf area index (LAI), leaf angle distribution (LAD), plant dimensions, soil optical properties, etc.) and scene (sun/ view angles and atmospheric conditions) has been undertaken. The radiosity model has let us gain a deep insight into the radiative regime inside the canopy, showing it to be governed by occlusion of incoming irradiance, multiple scattering of radiation between canopy elements and interception of upward radiance by leaves. Results have indicated that unlike leaf distribution, other structural parameters such as LAI, LAD, and plant dimensions have a strong influence on canopy reflectance. In addition, concepts have been developed that are useful to understand the reflectance behavior of the canopy, such as an effective LAI related to leaf inclination.

  4. CFD modelling and wind tunnel validation of airflow through plant canopies using 3D canopy architecture

    International Nuclear Information System (INIS)

    Endalew, A. Melese; Hertog, M.; Delele, M.A.; Baetens, K.; Persoons, T.; Baelmans, M.; Ramon, H.; Nicolai, B.M.; Verboven, P.

    2009-01-01

    The efficiency of pesticide application to agricultural fields and the resulting environmental contamination highly depend on atmospheric airflow. A computational fluid dynamics (CFD) modelling of airflow within plant canopies using 3D canopy architecture was developed to understand the effect of the canopy to airflow. The model average air velocity was validated using experimental results in a wind tunnel with two artificial model trees of 24 cm height. Mean air velocities and their root mean square (RMS) values were measured on a vertical plane upstream and downstream sides of the trees in the tunnel using 2D hotwire anemometer after imposing a uniform air velocity of 10 m s -1 at the inlet. 3D virtual canopy geometries of the artificial trees were modelled and introduced into a computational fluid domain whereby airflow through the trees was simulated using Reynolds-Averaged Navier-Stokes (RANS) equations and k-ε turbulence model. There was good agreement of the average longitudinal velocity, U between the measurements and the simulation results with relative errors less than 2% for upstream and 8% for downstream sides of the trees. The accuracy of the model prediction for turbulence kinetic energy k and turbulence intensity I was acceptable within the tree height when using a roughness length (y 0 = 0.02 mm) for the surface roughness of the tree branches and by applying a source model in a porous sub-domain created around the trees. The approach was applied for full scale orchard trees in the atmospheric boundary layer (ABL) and was compared with previous approaches and works. The simulation in the ABL was made using two groups of full scale orchard trees; short (h = 3 m) with wider branching and long (h = 4 m) with narrow branching. This comparison showed good qualitative agreements on the vertical profiles of U with small local differences as expected due to the spatial disparities in tree architecture. This work was able to show airflow within and above the

  5. Infectious Tolerance

    Science.gov (United States)

    Jonuleit, Helmut; Schmitt, Edgar; Kakirman, Hacer; Stassen, Michael; Knop, Jürgen; Enk, Alexander H.

    2002-01-01

    Regulatory CD4+CD25+ T cells (Treg) are mandatory for maintaining immunologic self-tolerance. We demonstrate that the cell-cell contact–mediated suppression of conventional CD4+ T cells by human CD25+ Treg cells is fixation resistant, independent from membrane-bound TGF-β but requires activation and protein synthesis of CD25+ Treg cells. Coactivation of CD25+ Treg cells with Treg cell–depleted CD4+ T cells results in anergized CD4+ T cells that in turn inhibit the activation of conventional, freshly isolated CD4+ T helper (Th) cells. This infectious suppressive activity, transferred from CD25+ Treg cells via cell contact, is cell contact–independent and partially mediated by soluble transforming growth factor (TGF)-β. The induction of suppressive properties in conventional CD4+ Th cells represents a mechanism underlying the phenomenon of infectious tolerance. This explains previously published conflicting data on the role of TGF-β in CD25+ Treg cell–induced immunosuppression. PMID:12119350

  6. Smartphone based hemispherical photography for canopy structure measurement

    Science.gov (United States)

    Wan, Xuefen; Cui, Jian; Jiang, Xueqin; Zhang, Jingwen; Yang, Yi; Zheng, Tao

    2018-01-01

    The canopy is the most direct and active interface layer of the interaction between plant and environment, and has important influence on energy exchange, biodiversity, ecosystem matter and climate change. The measurement about canopy structure of plant is an important foundation to analyze the pattern, process and operation mechanism of forest ecosystem. Through the study of canopy structure of plant, solar radiation, ambient wind speed, air temperature and humidity, soil evaporation, soil temperature and other forest environmental climate characteristics can be evaluated. Because of its accuracy and effectiveness, canopy structure measurement based on hemispherical photography has been widely studied. However, the traditional method of canopy structure hemispherical photogrammetry based on SLR camera and fisheye lens. This method is expensive and difficult to be used in some low-cost occasions. In recent years, smartphone technology has been developing rapidly. The smartphone not only has excellent image acquisition ability, but also has the considerable computational processing ability. In addition, the gyroscope and positioning function on the smartphone will also help to measure the structure of the canopy. In this paper, we present a smartphone based hemispherical photography system. The system consists of smart phones, low-cost fisheye lenses and PMMA adapters. We designed an Android based App to obtain the canopy hemisphere images through low-cost fisheye lenses and provide horizontal collimation information. In addition, the App will add the acquisition location tag obtained by GPS and auxiliary positioning method in hemisphere image information after the canopy structure hemisphere image acquisition. The system was tested in the urban forest after it was completed. The test results show that the smartphone based hemispherical photography system can effectively collect the high-resolution canopy structure image of the plant.

  7. Directional Canopy Emissivity Estimation Based on Spectral Invariants

    Science.gov (United States)

    Guo, M.; Cao, B.; Ren, H.; Yongming, D.; Peng, J.; Fan, W.

    2017-12-01

    Land surface emissivity is a crucial parameter for estimating land surface temperature from remote sensing data and also plays an important role in the physical process of surface energy and water balance from local to global scales. To our knowledge, the emissivity varies with surface type and cover. As for the vegetation, its canopy emissivity is dependent on vegetation types, viewing zenith angle and structure that changes in different growing stages. Lots of previous studies have focused on the emissivity model, but few of them are analytic and suited to different canopy structures. In this paper, a new physical analytic model is proposed to estimate the directional emissivity of homogenous vegetation canopy based on spectral invariants. The initial model counts the directional absorption in six parts: the direct absorption of the canopy and the soil, the absorption of the canopy and soil after a single scattering and after multiple scattering within the canopy-soil system. In order to analytically estimate the emissivity, the pathways of photons absorbed in the canopy-soil system are traced using the re-collision probability in Fig.1. After sensitive analysis on the above six absorptions, the initial complicated model was further simplified as a fixed mathematic expression to estimate the directional emissivity for vegetation canopy. The model was compared with the 4SAIL model, FRA97 model, FRA02 model and DART model in Fig.2, and the results showed that the FRA02 model is significantly underestimated while the FRA97 model is a little underestimated, on basis of the new model. On the contrary, the emissivity difference between the new model with the 4SAIL model and DART model was found to be less than 0.002. In general, since the new model has the advantages of mathematic expression with accurate results and clear physical meaning, the model is promising to be extended to simulate the directional emissivity for the discrete canopy in further study.

  8. Effect of shade on various parameters of Friesian cows in a ...

    African Journals Online (AJOL)

    levels and solar radiation on the production of lactating dairy cows, is well .... period. Cortisol concentration (nmol /l ). No shade. SEa. Significance. Shade. 1984/85. 1985/86. 26.91 -+ .... Florida differ from local conditions, being subtropical with higher maximum .... A gradual rise in rectal temperature was, however, evident at.

  9. Segmentation-based retrospective shading correction in fluorescence microscopy E. coli images for quantitative analysis

    Science.gov (United States)

    Mai, Fei; Chang, Chunqi; Liu, Wenqing; Xu, Weichao; Hung, Yeung S.

    2009-10-01

    Due to the inherent imperfections in the imaging process, fluorescence microscopy images often suffer from spurious intensity variations, which is usually referred to as intensity inhomogeneity, intensity non uniformity, shading or bias field. In this paper, a retrospective shading correction method for fluorescence microscopy Escherichia coli (E. Coli) images is proposed based on segmentation result. Segmentation and shading correction are coupled together, so we iteratively correct the shading effects based on segmentation result and refine the segmentation by segmenting the image after shading correction. A fluorescence microscopy E. Coli image can be segmented (based on its intensity value) into two classes: the background and the cells, where the intensity variation within each class is close to zero if there is no shading. Therefore, we make use of this characteristics to correct the shading in each iteration. Shading is mathematically modeled as a multiplicative component and an additive noise component. The additive component is removed by a denoising process, and the multiplicative component is estimated using a fast algorithm to minimize the intra-class intensity variation. We tested our method on synthetic images and real fluorescence E.coli images. It works well not only for visual inspection, but also for numerical evaluation. Our proposed method should be useful for further quantitative analysis especially for protein expression value comparison.

  10. Effects of shading on starch pasting characteristics of indica hybrid rice (Oryza sativa L..

    Directory of Open Access Journals (Sweden)

    Li Wang

    Full Text Available Rice is an important staple crop throughout the world, but environmental stress like low-light conditions can negatively impact crop yield and quality. Using pot experiments and field experiments, we studied the effects of shading on starch pasting viscosity and starch content with six rice varieties for three years, using the Rapid Visco Analyser to measure starch pasting viscosity. Shading at different growth stages and in different rice varieties all affected the starch pasting characteristics of rice. The effects of shading on starch pasting viscosity at middle and later growth stages were greater than those at earlier stages. Shading enhanced breakdown but reduced hold viscosity and setback at tillering-elongation stage. Most pasting parameters changed significantly with shading after elongation stage. Furthermore, the responses of different varieties to shading differed markedly. The change scope of starch pasting viscosity in Dexiang 4103 was rather small after heading, while that in IIyou 498 and Gangyou 906 was small before heading. We observed clear tendencies in peak viscosity, breakdown, and pasting temperature of the five rice varieties with shading in 2010 and 2011. Correlation analysis indicated that the rice amylose content was negatively correlated with breakdown, but was positively correlated with setback. Based on our results, IIyou 498, Gangyou 906, and Dexiang 4103 had higher shade endurance, making these varieties most suitable for high-quality rice cultivation in low-light regions.

  11. Effects of shading on starch pasting characteristics of indica hybrid rice (Oryza sativa L.).

    Science.gov (United States)

    Wang, Li; Deng, Fei; Ren, Wan-Jun; Yang, Wen-Yu

    2013-01-01

    Rice is an important staple crop throughout the world, but environmental stress like low-light conditions can negatively impact crop yield and quality. Using pot experiments and field experiments, we studied the effects of shading on starch pasting viscosity and starch content with six rice varieties for three years, using the Rapid Visco Analyser to measure starch pasting viscosity. Shading at different growth stages and in different rice varieties all affected the starch pasting characteristics of rice. The effects of shading on starch pasting viscosity at middle and later growth stages were greater than those at earlier stages. Shading enhanced breakdown but reduced hold viscosity and setback at tillering-elongation stage. Most pasting parameters changed significantly with shading after elongation stage. Furthermore, the responses of different varieties to shading differed markedly. The change scope of starch pasting viscosity in Dexiang 4103 was rather small after heading, while that in IIyou 498 and Gangyou 906 was small before heading. We observed clear tendencies in peak viscosity, breakdown, and pasting temperature of the five rice varieties with shading in 2010 and 2011. Correlation analysis indicated that the rice amylose content was negatively correlated with breakdown, but was positively correlated with setback. Based on our results, IIyou 498, Gangyou 906, and Dexiang 4103 had higher shade endurance, making these varieties most suitable for high-quality rice cultivation in low-light regions.

  12. Shade factors for 149 taxa of in-leaf urban trees in the USA

    Science.gov (United States)

    E. Gregory McPherson; Qingfu Xiao; Natalie S. van Doorn; Nels Johnson; Shannon Albers; Paula J. Peper

    2018-01-01

    Shade factors, defined as the percentage of sky covered by foliage and branches within the perimeter of individual tree crowns, have been used to model the effects of trees on air pollutant uptake, building energy use and rainfall interception. For the past 30 years the primary source of shade factors was a database containing values from 47 species. In most...

  13. Non-linear effects of drought under shade: reconciling physiological and ecological models in plant communities

    NARCIS (Netherlands)

    Holmgren, M.; Gomez-Aparicio, L.; Quero, J.L.; Valladares, F.

    2012-01-01

    The combined effects of shade and drought on plant performance and the implications for species interactions are highly debated in plant ecology. Empirical evidence for positive and negative effects of shade on the performance of plants under dry conditions supports two contrasting theoretical

  14. Effects of shade on growth, production and quality of coffee (Coffea arabica) in Ethiopia

    NARCIS (Netherlands)

    Bote, A.D.; Struik, P.C.

    2011-01-01

    The research work was conducted to evaluate the effect of shade on growth and production of coffee plants. To achieve this, growth and productivity of coffee plants growing under shade trees were compared with those of coffee plants growing under direct sun light. Different physiological,

  15. [Research on the designing method of a special shade guide for tooth whitening].

    Science.gov (United States)

    Xu, Yingxin

    2015-10-01

    To investigate a method of designing an accurate and scientific shade guide, especially used for judging the effect of tooth whitening, by analyzing the colorimetric values of discolored teeth statistically. One hundred thirty-six pictures of patients who had been receiving the Beyond cold light whitening treatment from February 2009 to July 2014 were analyzed, including 25 tetracycline teeth, 61 mottled-enamel teeth, and 50 yellow teeth. The colorimetric values of discolored teeth were measured. The L* values of shade tabs were calculated by hierarchical clustering of those of discolored teeth. The a* and b* values of shade tabs were the mean of those observed for discolored teeth. Accordingly, different shade guides were designed for each type of discolored teeth, and the effects were evaluated. A statistically significant difference in colorimetric values was found among the three types of discolored teeth. Compared with the Vitapan Classical shade guide, the shade guides designed through the present method were more scientific and accurate in judging the effect of tooth whitening. Moreover, the arrangement of shade tabs was more logical, and the color difference between shade tabs and discolored teeth was smaller. The proposed designing method is theoretically feasible, although its clinical effect has yet to be proven.

  16. Growth and production of new superior rice varieties in the shade intensity

    Science.gov (United States)

    Alridiwirsah; Harahap, E. M.; Akoeb, E. N.; Hanum, H.

    2018-02-01

    Shade intensity is one of the most important requirements for plant growth, affecting growth, development, survival, and crop productivity. This study aims to evaluate the growth and productiom of New Superior Rice Varieties In The shade Intensity. This study was conducted in Balai Pengkajian Teknologi Pertanian, Pagar Merbau, Deli Serdang, North Sumatra. The research used completely randomized design with twofactors. The shade intensity (N) were 25%, 50% and no shade intensity as a control. Whereas new superior rice varieties were V1: Inpara 2, V2: Suluttan Unsrat 2, V3: Inpari Mugibat, V4: Inpari Sidenuk, V5: Mekongga, V6: Ciherang, V7:Inpari 10, V8: Inpari 3, V9: Inpari 4, V10: Inpari 30, dan V11: Cibogo. The result indicated that new superior rice varietiesshowedsignificant effectonthe growth and productionvariablesuch as leaf area, where Inpari Sidenuk variety was the highest among the varieties. Total chorophyll, the highest was found on Inpari variety. Number of tillers and plant height where the highest was found on Ciherang variety. The shade intensity showed significant effect on leaf area, where 25% shade intensity was the highest. Total chlorophyll, the highest was found on 50% shade intensity, number of tillers, the highest was found on no shade intensity.

  17. Development and Performance Evaluation of a Rain Shade for a low ...

    African Journals Online (AJOL)

    Aderoju Tomiwa

    for a low scale agricultural produce, The rain shade consists of a geared D. C motor, 12V battery, ... rain shade was embarked on in this research work. ... (9) Face width, b. +. 5mm (10). Determination of weight acting on the Extension. Arm: The measured weight of the polyester fabric equals 14.7N, while the combined ...

  18. 29 CFR 780.506 - Dependence of exemption on shade-grown tobacco operations.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Dependence of exemption on shade-grown tobacco operations. 780.506 Section 780.506 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION....506 Dependence of exemption on shade-grown tobacco operations. The exemption provided by section 13(a...

  19. The effect of shade on chlorophyll and anthocyanin content of upland red rice

    Science.gov (United States)

    Muhidin; Syam'un, E.; Kaimuddin; Musa, Y.; Sadimantara, G. R.; Usman; Leomo, S.; Rakian, T. C.

    2018-02-01

    Upland red rice (Oryza sativa) is a staple food and contains anthocyanin, which can act as antioxidants, plays an important role both for the plant itself and for human health. Levels of antioxidants in rice can be affected by the availability of light. The results showed that the difference of shade, cultivar, and interaction both significantly affect the content of chlorophyll a, chlorophyll b and total chlorophyll. The results also showed that shade could increase chlorophyll in all cultivars tested. The highest levels of chlorophyll a were present in the moderate shade level (n2), then decreased at the shelter level (n3) and increased again at high levels (n4). While on chlorophyll content b, it appears that shade increased chlorophyll b in all cultivars tested and this increase was linear to the increase of shade. The shade treatment may increase the anthocyanin content and the increase depending on the type of cultivar. Increased levels of anthocyanin highest due to shade occurred on Jangkobembe cultivar. The original level of anthocyanin on Jangkobembe cultivar averaged 0.096 mg g-1 increased to 2.487 mg g-1 or increased 26 fold. It is concluded that the shade had a significant effect on the chlorophyll and anthocyanin content.

  20. Effects of shading on Vallisneria natans (Lour.) H. Hara growth

    DEFF Research Database (Denmark)

    Fox, Anthony David; Meng, F; Shen, X

    2013-01-01

    , but dry weight fruit production was significantly reduced at 90% shading. We conclude that above 50% surface shading, V. natans plants suffer reductions in accumulated biomass and investment in sexual reproduction. We contend that recent expansions in the extent of the native floating water chestnut Trapa...

  1. 29 CFR 780.505 - Definition of “shade-grown tobacco.”

    Science.gov (United States)

    2010-07-01

    ... Employment or Agricultural Employees in Processing Shade-Grown Tobacco; Exemption From Minimum Wage and... 29 Labor 3 2010-07-01 2010-07-01 false Definition of âshade-grown tobacco.â 780.505 Section 780.505 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR...

  2. The production of Physalis spp. seedlings grown under different-colored shade nets

    Directory of Open Access Journals (Sweden)

    Daniel Fernandes da Silva

    2016-04-01

    Full Text Available The objective of this study was to evaluate the production of seedlings of Physalis L. species under different-colored shade nets. Four shade nets individually stained white, blue, red and black, all with 50% shading, were used in this study, and an additional  treatment (control was used in which seedlings were grown in full sun. The study examined four species of Physalis, namely, P. peruviana, P. pubescens, P. minima and P. ixocarpa. The experiment followed a randomized block design with three blocks and 25 seeds per plot. The species were sown in styrofoam trays. Germination was monitored daily to calculate the Emergency Velocity Index (EVI and stabilize the overall percentage of emergence. Height, stem diameter, number of leaves, leaf area index and dry mass of seedlings were assessed at 50 days after sowing. The study found that these species react differently to changes in the light spectrum. Seedlings of P. peruviana should be grown under a white or red shade net; of P. pubescens under a white or black shade net; of P. minima under a white, red or black shade net; and of P. ixocarpa under a white shade net. For all species, 50% shade should be used.

  3. Potential Sources of Polarized Light from a Plant Canopy

    Science.gov (United States)

    Vanderbilt, Vern; Daughtry, Craig; Dahlgren, Robert

    2016-01-01

    Field measurements have demonstrated that sunlight polarized during a first surface reflection by shiny leaves dominates the optical polarization of the light reflected by shiny-leafed plant canopies having approximately spherical leaf angle probability density functions ("Leaf Angle Distributions" - LAD). Yet for other canopies - specifically those without shiny leaves and/or spherical LADs - potential sources of optically polarized light may not always be obvious. Here we identify possible sources of polarized light within those other canopies and speculate on the ecologically important information polarization measurements of those sources might contain.

  4. Effect of ceramic thickness and cement shade on the final shade after bonding using the 3D master system: a laboratory study.

    Science.gov (United States)

    Montero, Javier; Gómez-Polo, Cristina

    2016-06-01

    The final color of a ceramic restoration is influenced by both the ceramic thickness and the cement shade. This study aims to evaluate the color stability according to the 3D Master System of e.max ceramic discs after bonding with different shades of luting agents. A total of 120 e.max.Press 2M1 HT ceramic discs (60 discs of 1-mm thick and 60 discs of 0.5 mm thick) and three different values of Variolink Veneer cement were used (-3, 0, +3) for the cementation process. An Easyshade compact device was used to measure color shade tabs, according to the 3D Master System, on the discs both before and after the cementation protocols. Bivariate and multivariate analyses were carried out with the spss v.21. After bonding with the different luting agents, only 30% remained as 2M1: specifically, 22% of the thinner discs and 37.3% of the thicker discs. In general, the effect of bonding increased the value and the chroma of the shade to a significant extent. Regression analyses revealed that the most significant predictor for all color parameters was cement shade, the thinner disc group bonded with -3 cement being the most unstable subgroup. According to the 3D Master System, the shade of the luting agent was the main predictor of the final color. However, the final color seems to be somewhat unpredictable, at least according to the modulating factors evaluated in the present study.

  5. The effects of providing portable shade at pasture on dairy cow behavior and physiology.

    Science.gov (United States)

    Palacio, S; Bergeron, R; Lachance, S; Vasseur, E

    2015-09-01

    Access to pasture has advantages for cows such as reduced lameness and improved udder health, but also may expose cows to stressors such as extreme heat. The objective of this study was to understand how portable shade affected physiological and behavioral responses of pastured dairy cows in a Canadian summer. Over 8wk, a total of 24 lactating Holstein cows were separated into 2 treatments, one with access to shade and a control without access to shade. The cows were pastured in groups of 4, with 3 field sections per treatment. Instantaneous scan sampling of behaviors (drinking, lying, grazing, other) performed in the shade or not were recorded every 5min for 3h/d during the hottest part of the day (peak hours: 1130-1530h) 3d/wk. Ambient temperature, humidity, and vaginal temperature were recorded at 10-min intervals. Daily milk production was also recorded. Differences between treatments by week were analyzed using the generalized linear mixed model with group as random effect and treatment as fixed effect. Cows with shade access were observed at the water trough up to 6.42 times less and lying down up to 1.75 times more. Cows with shade access grazed up to 1.5 times more but only when the temperature-humidity index was above their comfort threshold (≥72) during the hottest part of the day (wk 2). Cows sought shade when it was made available, but spent less than half of their time observed (%) in the shade (40.8±4.67) with the exception of wk 2 when most of the time was spent under the shade (74.3±4.77). Daily lying time was highest during peak hours for cows with shade access. However, no overall difference in total lying time between the 2 treatments was observed. No differences were found in vaginal temperature or milk production between treatments with the exception of wk 1 for daily milk production, which was higher for cows in the control treatment. In conclusion, cows sought shade when it was provided at pasture, whereas cows without access to shade

  6. World in Mercator Projection, Shaded Relief and Colored Height

    Science.gov (United States)

    2003-01-01

    This image of the world was generated with data from the Shuttle Radar Topography Mission (SRTM). The SRTM Project has recently released a new global data set called SRTM30, where the original one arcsecond of latitude and longitude resolution (about 30 meters, or 98 feet, at the equator) was reduced to 30 arcseconds (about 928 meters, or 1496 feet.) This image was created from that data set and shows the world between 60 degrees south and 60 degrees north latitude, covering 80% of the Earth's land mass. The image is in the Mercator Projection commonly used for maps of the world.Two visualization methods were combined to produce the image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction, so that northwest slopes appear bright and southeast slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations.Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise,Washington, D.C.Orientation: North toward the top, Mercator projection Image Data: shaded and colored SRTM

  7. Shaded Relief with Color as Height, California Mosaic

    Science.gov (United States)

    2002-01-01

    The diversity of landforms that make up the state of California is evident in this new rendition of the 3-D topography of the state. The Central Valley, flanked on the east by the Sierra Nevada, dominates the scene with San Francisco and Monterey Bays clearly visible at left center. Other features of interest include Lake Tahoe at the edge to the right of San Francisco, Mono Lake below Lake Tahoe, and the Salton Sea at the lower right. The prominent sideways 'V' in the southern part of the state is the intersection of the Garlock and San Andreas Faults - to the east is the Mojave Desert. Offshore are the Channel Islands and to the right of them lies the city of Los Angeles.Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction. North-facing slopes appear bright and south-facing slopes appear dark. Color coding is directly related to topographic height, with blue and green at the lower elevations, rising through yellow and brown to white at the highest elevations.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar(SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science

  8. Alpine Fault, New Zealand, SRTM Shaded Relief and Colored Height

    Science.gov (United States)

    2005-01-01

    The Alpine fault runs parallel to, and just inland of, much of the west coast of New Zealand's South Island. This view was created from the near-global digital elevation model produced by the Shuttle Radar Topography Mission (SRTM) and is almost 500 kilometers (just over 300 miles) wide. Northwest is toward the top. The fault is extremely distinct in the topographic pattern, nearly slicing this scene in half lengthwise. In a regional context, the Alpine fault is part of a system of faults that connects a west dipping subduction zone to the northeast with an east dipping subduction zone to the southwest, both of which occur along the juncture of the Indo-Australian and Pacific tectonic plates. Thus, the fault itself constitutes the major surface manifestation of the plate boundary here. Offsets of streams and ridges evident in the field, and in this view of SRTM data, indicate right-lateral fault motion. But convergence also occurs across the fault, and this causes the continued uplift of the Southern Alps, New Zealand's largest mountain range, along the southeast side of the fault. Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast (image top to bottom) direction, so that northwest slopes appear bright and southeast slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations. Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data

  9. Shaded Relief with Color as Height, St. Louis, Missouri

    Science.gov (United States)

    2002-01-01

    The confluence of the Mississippi, Missouri and Illinois rivers are shown in this view of the St. Louis area from the Shuttle Radar Topography Mission. The Mississippi flows from the upper left of the image and first meets the Illinois, flowing southward from the top right. It then joins the Missouri, flowing from the west across the center of the picture. The rivers themselves appear black here, and one can clearly see the green-colored floodplains in which they are contained. These floodplains are at particular risk during times of flooding. The Mississippi forms the state boundary between Illinois (to the right) and Missouri (to the left), with the city of St. Louis located on the Mississippi just below the point where it meets the Missouri. This location at the hub of the major American waterways helped establish St. Louis' reputation as the 'Gateway to the West.'Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction. North-facing slopes appear bright and south-facing slopes appear dark. Color coding is directly related to topographic height, with blue and green at the lower elevations, rising through yellow and brown to white at the highest elevations.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar(SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping

  10. Shenandoah National Park, Virginia, Shaded Relief with Height as Color

    Science.gov (United States)

    2003-01-01

    Shenandoah National Park lies astride part of the Blue Ridge Mountains, which form the southeastern range of the greater Appalachian Mountains in Virginia. The park is well framed by this one-degree of latitude (38-39 north) by one-degree of longitude (78-79 west) cell of Shuttle Radar Topography Mission data, and it appears here as the most prominent ridge trending diagonally across the scene. Skyline Drive, a 169-kilometer (105-mile) road that winds along the crest of the mountains through the length the park, provides vistas of the surrounding landscape. The Shenandoah River flows through the valley to the west, with Massanutten Mountain standing between the river's north and south forks. Unusually pronounced meanders of both river forks are very evident near the top center of this scene. Massanutten Mountain itself is an unusually distinctive landform also, consisting of highly elongated looping folds of sedimentary rock. The rolling Piedmont country lies to the southeast of the park, with Charlottesville located at the bottom center of the scene.Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow, red, and magenta, to bluish-white at the highest elevations.Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on February 11, 2000. The mission used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar that flew twice on the Space Shuttle Endeavour in 1994. The Shuttle Radar Topography Mission was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60

  11. SRTM Colored Height and Shaded Relief: Lava plateaus in Argentina

    Science.gov (United States)

    2001-01-01

    All of the major landforms relate to volcanism and/or erosion in this Shuttle Radar Topography Mission scene of Patagonia, near La Esperanza, Argentina. The two prominent plateaus once formed a continuous surface that extended over much of this region. Younger volcanoes have grown through and atop the plateau, and one just south of this scene has sent a long, narrow flow down a stream channel (lower left). The topographic pattern shows that streams dominate the erosion processes in this arid environment even though wind is known to move substantial amounts of sediment here.Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear dark, as would be the case at noon at this latitude in the southern hemisphere. Color-coding is directly related to topographic height, with green at the lower elevations, rising through yellow, red, and magenta, to white at the highest elevations.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense, and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.Size: 62.4 by 88.8 kilometers

  12. Mts. Agung and Batur, Bali, Shaded Relief and Colored Height

    Science.gov (United States)

    2004-01-01

    This perspective view shows the major volcanic group of Bali, one 13,000 islands comprising the nation of Indonesia. The conical mountain to the left is Gunung Agung, at 3,148 meters (10,308 feet) the highest point on Bali and an object of great significance in Balinese religion and culture. Agung underwent a major eruption in 1963 after more than 100 years of dormancy, resulting in the loss of over 1,000 lives.In the center is the complex structure of Batur volcano, showing a caldera (volcanic crater) left over from a massive catastrophic eruption about 30,000 years ago. Judging from the total volume of the outer crater and the volcano, that once lay above it, approximately 140 cubic kilometers(33.4 cubic miles) of material must have been produced by this eruption, making it one of the largest known volcanic events on Earth. Batur is still active and has erupted at least 22 times since the 1800's.Two visualization methods were combined to produce the image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction, so that northwest slopes appear bright and southeast slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations.Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National

  13. SRTM Colored Height and Shaded Relief: Near Zapala, Argentina

    Science.gov (United States)

    2001-01-01

    Topographic data provided by the Shuttle Radar Topography Mission can provide many clues to geologic history and processes. This view of an area southwest of Zapala, Argentina, shows a wide diversity of geologic features. The highest peaks (left) appear to be massive (un-layered)crystalline rocks, perhaps granites. To their right (eastward) are tilted and eroded layered rocks, perhaps old lava flows, forming prominent ridges. Farther east and south, more subtle and curvilinear ridges show that the rock layers have not only been tilted but also folded. At the upper right, plateaus that cap the underlying geologic complexities are more recent lava flows - younger than the folding, but older than the current erosional pattern. Landforms in the southeast (lower right) and south-central areas appear partially wind sculpted.Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear dark, as would be the case at noon at this latitude in the southern hemisphere. Color-coding is directly related to topographic height, with green at the lower elevations, rising through yellow, red, and magenta, to white at the highest elevations.Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard Space Shuttle Endeavour, launched on February 11,2000. The mission used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar that flew twice on Space Shuttle Endeavour in 1994. Shuttle Radar Topography Mission was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National

  14. SRTM Colored Height and Shaded Relief: Las Bayas, Argentina

    Science.gov (United States)

    2001-01-01

    The interplay of volcanism, stream erosion and landslides is evident in this Shuttle Radar Topography Mission view of the eastern flank of the Andes Mountains, southeast of San Carlos de Bariloche, Argentina. Older lava flows emanating from the Andes once covered much of this area. Younger, local volcanoes (seen here as small peaks) then covered parts of the area with fresh, erosion resistant flows (seen here as very smooth surfaces). Subsequent erosion has created fine patterns on the older surfaces (bottom of the image) and bolder, irregular patterns through and around the younger surfaces (upper center and right center). Meanwhile, where a large stream immediately borders the resistant plateau (center of the image), lateral erosion has undercut the resistant plateau causing slivers of it to fall into the stream channel. This scene well illustrate show topographic data alone can reveal some aspects of recent geologic history.Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear dark, as would be the case at noon at this latitude in the southern hemisphere. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow, red, and magenta, to white at the highest elevations.Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on February 11, 2000. The mission used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar that flew twice on the Space Shuttle Endeavour in 1994. The Shuttle Radar Topography Mission was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, installed additional C-band and

  15. Optimization of partially shaded PV array using a modified P&O MPPT algorithm

    Directory of Open Access Journals (Sweden)

    Abdelaziz YOUCEF

    2016-07-01

    Full Text Available A photovoltaic (PV array generated power is directly affected by temperature, solar irradiation, shading, and array configuration. In practice, PV arrays could be partially shaded by could, buildings, trees and other utilities. In this case, multiple maximums appear in the P-V curve, a global maximum and one or several local maximums. The “perturb and observe“ (P&O maximum power point tracking (MPPT algorithm cannot differentiate between a global and a local maximum and it is therefore ineffective when partial shading occurs. First, this paper presents an original mathematical model of the P-V curve of a partially shaded PV array, that was used to perform a simulation study in order to show the P&O algorithm inability to track the global MPP of a PV array solar system under partial shading for low shading irradiation levels, then an adaptation sub algorithm is proposed to be added to the P&O algorithm in order to give it the ability to track the global MPP. This sub algorithm moves the operating point imposed by the partial shading configuration to a point in the vicinity of the global MPP in order to be easily tracked by the P&O algorithm. In the simulation, a PV array with a hundred modules has been considered by using a light, a medium then a severe shading configuration. The results obtained indicate that the proposed modified P&O algorithm is able to track the global MPP for the considered shading configurations and for any shading irradiation level.

  16. Assessment of color parameters of composite resin shade guides using digital imaging versus colorimeter.

    Science.gov (United States)

    Yamanel, Kivanc; Caglar, Alper; Özcan, Mutlu; Gulsah, Kamran; Bagis, Bora

    2010-12-01

    This study evaluated the color parameters of resin composite shade guides determined using a colorimeter and digital imaging method. Four composite shade guides, namely: two nanohybrid (Grandio [Voco GmbH, Cuxhaven, Germany]; Premise [KerrHawe SA, Bioggio, Switzerland]) and two hybrid (Charisma [Heraeus Kulzer, GmbH & Co. KG, Hanau, Germany]; Filtek Z250 [3M ESPE, Seefeld, Germany]) were evaluated. Ten shade tabs were selected (A1, A2, A3, A3,5, A4, B1, B2, B3, C2, C3) from each shade guide. CIE Lab values were obtained using digital imaging and a colorimeter (ShadeEye NCC Dental Chroma Meter, Shofu Inc., Kyoto, Japan). The data were analyzed using two-way analysis of variance and Bonferroni post hoc test. Overall, the mean ΔE values from different composite pairs demonstrated statistically significant differences when evaluated with the colorimeter (p 6.8). For all shade pairs evaluated, the most significant shade mismatches were obtained between Grandio-Filtek Z250 (p = 0.021) and Filtek Z250-Premise (p = 0.01) regarding ΔE mean values, whereas the best shade match was between Grandio-Charisma (p = 0.255) regardless of the measurement method. The best color match (mean ΔE values) was recorded for A1, A2, and A3 shade pairs in both methods. When proper object-camera distance, digital camera settings, and suitable illumination conditions are provided, digital imaging method could be used in the assessment of color parameters. Interchanging use of shade guides from different composite systems should be avoided during color selection. © 2010, COPYRIGHT THE AUTHORS. JOURNAL COMPILATION © 2010, WILEY PERIODICALS, INC.

  17. ForestCrowns: a software tool for analyzing ground-based digital photographs of forest canopies

    Science.gov (United States)

    Matthew F. Winn; Sang-Mook Lee; Phillip A. Araman

    2013-01-01

    Canopy coverage is a key variable used to characterize forest structure. In addition, the light transmitted through the canopy is an important ecological indicator of plant and animal habitat and understory climate conditions. A common ground-based method used to document canopy coverage is to take digital photographs from below the canopy. To assist with analyzing...

  18. Enhanced canopy growth precedes senescence in 2005 and 2010 Amazonian droughts

    KAUST Repository

    Liu, Yi Y.

    2018-04-09

    Unprecedented droughts hit southern Amazonia in 2005 and 2010, causing a sharp increase in tree mortality and carbon loss. To better predict the rainforest\\'s response to future droughts, it is necessary to understand its behavior during past events. Satellite observations provide a practical source of continuous observations of Amazonian forest. Here we used a passive microwave-based vegetation water content record (i.e., vegetation optical depth, VOD), together with multiple hydrometeorological observations as well as conventional satellite vegetation measures, to investigate the rainforest canopy dynamics during the 2005 and 2010 droughts. During the onset of droughts in the wet-to-dry season (May–July) of both years, we found large-scale positive anomalies in VOD, leaf area index (LAI) and enhanced vegetation index (EVI) over the southern Amazonia. These observations are very likely caused by enhanced canopy growth. Concurrent below-average rainfall and above-average radiation during the wet-to-dry season can be interpreted as an early arrival of normal dry season conditions, leading to enhanced new leaf development and ecosystem photosynthesis, as supported by field observations. Our results suggest that further rainfall deficit into the subsequent dry season caused water and heat stress during the peak of 2005 and 2010 droughts (August–October) that exceeded the tolerance limits of the rainforest, leading to widespread negative VOD anomalies over the southern Amazonia. Significant VOD anomalies were observed mainly over the western part in 2005 and mainly over central and eastern parts in 2010. The total area with significant negative VOD anomalies was comparable between these two drought years, though the average magnitude of significant negative VOD anomalies was greater in 2005. This finding broadly agrees with the field observations indicating that the reduction in biomass carbon uptake was stronger in 2005 than 2010. The enhanced canopy growth

  19. Enhanced canopy growth precedes senescence in 2005 and 2010 Amazonian droughts

    KAUST Repository

    Liu, Yi Y.; van Dijk, Albert I.J.M.; Miralles, Diego G.; McCabe, Matthew; Evans, Jason P.; de Jeu, Richard A.M.; Gentine, Pierre; Huete, Alfredo; Parinussa, Robert M.; Wang, Lixin; Guan, Kaiyu; Berry, Joe; Restrepo-Coupe, Natalia

    2018-01-01

    Unprecedented droughts hit southern Amazonia in 2005 and 2010, causing a sharp increase in tree mortality and carbon loss. To better predict the rainforest's response to future droughts, it is necessary to understand its behavior during past events. Satellite observations provide a practical source of continuous observations of Amazonian forest. Here we used a passive microwave-based vegetation water content record (i.e., vegetation optical depth, VOD), together with multiple hydrometeorological observations as well as conventional satellite vegetation measures, to investigate the rainforest canopy dynamics during the 2005 and 2010 droughts. During the onset of droughts in the wet-to-dry season (May–July) of both years, we found large-scale positive anomalies in VOD, leaf area index (LAI) and enhanced vegetation index (EVI) over the southern Amazonia. These observations are very likely caused by enhanced canopy growth. Concurrent below-average rainfall and above-average radiation during the wet-to-dry season can be interpreted as an early arrival of normal dry season conditions, leading to enhanced new leaf development and ecosystem photosynthesis, as supported by field observations. Our results suggest that further rainfall deficit into the subsequent dry season caused water and heat stress during the peak of 2005 and 2010 droughts (August–October) that exceeded the tolerance limits of the rainforest, leading to widespread negative VOD anomalies over the southern Amazonia. Significant VOD anomalies were observed mainly over the western part in 2005 and mainly over central and eastern parts in 2010. The total area with significant negative VOD anomalies was comparable between these two drought years, though the average magnitude of significant negative VOD anomalies was greater in 2005. This finding broadly agrees with the field observations indicating that the reduction in biomass carbon uptake was stronger in 2005 than 2010. The enhanced canopy growth

  20. Performance of a daylight-redirecting glass-shading system

    DEFF Research Database (Denmark)

    Appelfeld, David; Svendsen, Svend

    2013-01-01

    to the original system. The visual comfort was evaluated by glare analysis and the redirected daylight did not cause an additional discomfort glare. The higher utilization of daylight can save 20% of the lighting energy. The thermal insulation of the fenestration was maintained, with slightly increased solar......This paper evaluates the daylighting performance of a prototype external dynamic shading and daylight-redirecting system, and the main focus is on the performance simulation. The demonstration project was carried out on a building with an open-plan office. Part of the original façade was replaced...... with the prototype façade. This layout allowed the use of the same orientation and surroundings for both façades. The working plane illuminance was measured over several months and the measurements were accompanied with annual daylight simulations. The prototype system improved the daylighting conditions compared...

  1. Mt. Elgon, Africa, Shaded Relief and Colored Height

    Science.gov (United States)

    2004-01-01

    The striking contrast of geologic structures in Africa is shown in this shaded relief image of Mt. Elgon on the left and a section of the Great Rift Valley on the right. Mt. Elgon is a solitary extinct volcano straddling the border between Uganda and Kenya, and at 4,321 meters (14,178 feet) tall is the eighth highest mountain in Africa. It is positioned on the Pre-Cambriam bedrock of the Trans Nzoia Plateau, and is similar to other such volcanoes in East Africa in that it is associated with the formation of the Rift Valley. However one thing that sets Mt. Elgon apart is its age. Although there is no verifiable evidence of its earliest volcanic activity, Mt. Elgon is estimated to be at least 24 million years old, making it the oldest extinct volcano in East Africa. This presents a striking comparison to Mt. Kilimanjaro, the highest mountain in Africa at 5,895 meters (19,341 feet), which is just over one million years old. Judging by the diameter of its base, it is a common belief among geological experts that Mt. Elgon was once the highest mountains in Africa, however erosion has played a significant role in reducing the height to its present value. Juxtaposed with this impressive mountain is a section of the Great Rift Valley, a geological fault system that extends for about 4,830 kilometers (2,995 miles) from Syria to central Mozambique. Erosion has concealed some sections, but in some sections like that shown here, there are sheer cliffs several thousand feet high. The present configuration of the valley, which dates from the mid-Pleistocene epoch, results from a rifting process associated with thermal currents in the Earth's mantle. Two visualization methods were combined to produce the image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction, so that northwest slopes appear bright and southeast slopes appear dark. Color coding is directly related to topographic height

  2. Shaded Relief with Height as Color, Yucatan Peninsula, Mexico

    Science.gov (United States)

    2003-01-01

    This shaded relief image of Mexico's Yucatan Peninsula show a subtle, but unmistakable, indication of the Chicxulub impact crater. Most scientists now agree that this impact was the cause of the Cretatious-Tertiary Extinction, the event 65 million years ago that marked the sudden extinction of the dinosaurs as well as the majority of life then on Earth.Most of the peninsula is visible here, along with the island of Cozumel off the east coast. The Yucatan is a plateau composed mostly of limestone and is an area of very low relief with elevations varying by less than a few hundred meters (about 500 feet.) In this computer-enhanced image the topography has been greatly exaggerated to highlight a semicircular trough, the darker green arcing line at the upper left corner of the peninsula. This trough is only about 3 to 5 meters (10 to 15 feet) deep and is about 5 km. wide (3 miles), so subtle that if you walked across it you probably would not notice it, and is a surface expression of the crater's outer boundary. Scientists believe the impact, which was centered just off the coast in the Caribbean, altered the subsurface rocks such that the overlying limestone sediments, which formed later and erode very easily, would preferentially erode on the vicinity of the crater rim. This formed the trough as well as numerous sinkholes (called cenotes) which are visible as small circular depressions.Two visualization methods were combined to produce the image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction, so that northwestern slopes appear bright and southeastern slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations.For a smaller, annotated version of this image, please select Figure 1, below: [figure removed for brevity, see original site] (Large image: 1.5 m

  3. Rotor Systems Research Aircraft /RSRA/ canopy explosive severance/fracture

    Science.gov (United States)

    Bement, L. J.

    1976-01-01

    The Rotor Systems Research Aircraft (RSRA), a compound rotor/fixed-wing aircraft, incorporates an emergency escape system for the three crew members; to achieve unobstructed egress, the overhead acrylic canopies of each crew member will be explosively severed and fractured into predictably small, low-mass pieces. A canopy explosive severance/fracture system was developed under this investigation that included the following system design considerations: selection of canopy and explosive materials, determining the acrylic's explosive severance and fracture characteristics, evaluating the effects of installation variables and temperature, determining the most effective explosive patterns, conducting full-scale, flat and double-curvature canopy tests, and evaluating the effects of back-blast of the explosive into the cockpit.

  4. Assessing the vegetation canopy influences on wind flow using wind ...

    Indian Academy of Sciences (India)

    Artificial plastic vegetations with different porosity and canopy shape were introduced as ... Wind erosion is the Aeolian process by which soil particles are detached from ..... the stabilizing role of vegetation on wind erosion. And therefore, for ...

  5. Canopy Dynamics in Nanoscale Ionic Materials Probed by NMR

    Science.gov (United States)

    Mirau, Peter

    2013-03-01

    Nanoscale ionic materials (NIMs) are hybrids prepared from ionically functionalized nanoparticles (NP) neutralized by oligomeric polymer counter-ions. NIMs are designed to behave as liquids under ambient conditions in the absence of solvent and have no volatile organic content, making them useful for a number of applications. We have used NMR relaxation and pulse-field gradient NMR to probe local and collective canopy dynamics in NIMs based on silica nanoparticles (NP), fullerols and proteins in order to understand the relationship between the core and canopy structure and the bulk properties. The NMR studies show that the canopy dynamics depend on the degree of neutralization, the canopy radius of gyration and molecular crowding at the ionically modified NP surface. The viscosity in NIMs can be directly controlled with the addition of ions that enhance the exchange rate for polymers at the NP surface. These results show that NIMs for many applications can be prepared by controlling the dynamics of the NP interface.

  6. National Land Cover Database (NLCD) Percent Tree Canopy Collection

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The National Land Cover Database (NLCD) Percent Tree Canopy Collection is a product of the U.S. Forest Service (USFS), and is produced through a cooperative project...

  7. Aerial electrostatic spray deposition and canopy penetration in cotton

    Science.gov (United States)

    Spray deposition on abaxial and adaxial leaf surfaces along with canopy penetration are essential for insect control and foliage defoliation in cotton production agriculture. Researchers have reported that electrostatically charged sprays have increased spray deposit onto these surfaces under widel...

  8. Assessment of the influence of gender and skin color on the preference of tooth shade in Saudi population

    Directory of Open Access Journals (Sweden)

    Nawaf Labban

    2017-07-01

    Conclusion: Gender and skin color influences the perception of teeth shades among general population. Therefore, lighter tooth shades (BL1, BL2 for lighter skin color and comparatively darker tooth shades (BL4, B1, A1 for darker skin individuals should be prescribed as these are perceived as natural among Saudi population.

  9. ALTERNATIVE APIARIES SHADING ALTERNATIVAS DE SOMBREAMENTO PARA APIÁRIOS

    Directory of Open Access Journals (Sweden)

    Ricardo Costa Rodrigues de Camargo

    2011-07-01

    Full Text Available

    Beehives shading can be a strategy to minimize the heat stress suffered by bees in tropical regions such as the Northeastern Brazil. So, the objective of this study was to evaluate the influence of different beehives shading conditions on the development and quality of honey produced in Apis mellifera colonies. The experiment was carried out in an apiary owned by the Embrapa Meio-Norte, in Castelo do Piauí, Piauí State, Brazil. Bee colonies were placed under the shade provided by straw, polypropylene screen (80% shading, and trees, and under direct solar radiation, in a completely randomized design, with six replications. Data concerning beehives weight and breeding and feeding areas were analyzed by using the Kruskal-Wallis test. Honey samples collected from beehives were submitted to chemical analyses, in order to determine hydroxymethylfurfural (HMF, acidity, and diastase activities. It was observed that the artificial covers did not provide significant beneficial effects on the colonies development. Thermoregulation was impaired

  10. Freezing and low temperature photoinhibition tolerance in cultivated potato and potato hybrids

    Directory of Open Access Journals (Sweden)

    M.M. SEPPÄNEN

    2008-12-01

    Full Text Available Four Solanum tuberosum L. cultivars (Nicola, Pito, Puikula, Timo and somatic hybrids between freezing tolerant S. commersonii and freezing sensitive S. tuberosum were evaluated for their tolerance to freezing and low temperature photoinhibition. Cellular freezing tolerance was studied using ion leakage tests and the sensitivity of the photosynthetic apparatus to freezing and high light intensity stress by measuring changes in chlorophyll fluorescence (FV/FM and oxygen evolution. Exposure to high light intensities after freezing stress increased frost injury significantly in all genotypes studied. Compared with S. tuberosum cultivars, the hybrids were more tolerant both of freezing and intense light stresses. In field experiments the mechanism of frost injury varied according to the severity of night frosts. During night frosts in 1999, the temperature inside the potato canopy was significantly higher than at ground level, and did not fall below the lethal temperature for potato cultivars (from -2.5 to -3.0°C. As a result, frost injury developed slowly, indicating that damage occurred to the photosynthetic apparatus. However, as the temperature at ground level and inside the canopy fell below -4°C, cellular freezing occurred and the canopy was rapidly destroyed. This suggests that in the field visual frost damage can follow from freezing or non-freezing temperatures accompanied with high light intensity. Therefore, in an attempt to improve low temperature tolerance in potato, it is important to increase tolerance to both freezing and chilling stresses.

  11. Simulation of ICESat-2 canopy height retrievals for different ecosystems

    Science.gov (United States)

    Neuenschwander, A. L.

    2016-12-01

    Slated for launch in late 2017 (or early 2018), the ICESat-2 satellite will provide a global distribution of geodetic measurements from a space-based laser altimeter of both the terrain surface and relative canopy heights which will provide a significant benefit to society through a variety of applications ranging from improved global digital terrain models to producing distribution of above ground vegetation structure. The ATLAS instrument designed for ICESat-2, will utilize a different technology than what is found on most laser mapping systems. The photon counting technology of the ATLAS instrument onboard ICESat-2 will record the arrival time associated with a single photon detection. That detection can occur anywhere within the vertical distribution of the reflected signal, that is, anywhere within the vertical distribution of the canopy. This uncertainty of where the photon will be returned from within the vegetation layer is referred to as the vertical sampling error. Preliminary simulation studies to estimate vertical sampling error have been conducted for several ecosystems including woodland savanna, montane conifers, temperate hardwoods, tropical forest, and boreal forest. The results from these simulations indicate that the canopy heights reported on the ATL08 data product will underestimate the top canopy height in the range of 1 - 4 m. Although simulation results indicate the ICESat-2 will underestimate top canopy height, there is, however, a strong correlation between ICESat-2 heights and relative canopy height metrics (e.g. RH75, RH90). In tropical forest, simulation results indicate the ICESat-2 height correlates strongly with RH90. Similarly, in temperate broadleaf forest, the simulated ICESat-2 heights were also strongly correlated with RH90. In boreal forest, the simulated ICESat-2 heights are strongly correlated with RH75 heights. It is hypothesized that the correlations between simulated ICESat-2 heights and canopy height metrics are a

  12. Response of leaf and whole-tree canopy conductance to wet conditions within a mature premontane tropical forest in Costa Rica

    Science.gov (United States)

    Aparecido, L. M. T.; Miller, G. R.; Cahill, A. T.; Andrews, R.; Moore, G. W.

    2017-12-01

    Tropical water recycling and carbon storage are dependent on canopy-atmosphere dynamics, which are substantially altered when rainfall occurs. However, models only indirectly consider leaf wetness as a driving factor for carbon and water fluxes. To better understand how leaf wetness condition affects stomatal and canopy conductance to water vapor, we tested a set of widely used models for a mature tropical forest of Costa Rica with prolonged periods of wet leaves. We relied on a year of sap flux measurements from 26 trees to estimate transpiration (Ec) and multiple micrometeorological profile measurements from a 40-m tower to be used in the models. Stomatal conductance (gs) models included those proposed by Jones (1992) (gs-J), using shaded and sunlit leaf temperatures, and Monteith and Unsworth (1990) (gs-MU), using air temperature. Canopy conductance (gc) models included those proposed by McNaughton and Jarvis (1983) (gc-MJ) and Penman-Monteith (gc-PM). Between gs and gc, gc had the largest differences within models during dry periods; while estimates were most similar during wet periods. Yet, all gc and gs estimates on wet days were at least as high as on dry days, indicative of their insensitivity to leaf wetness. Shaded leaf gs averaged 26% higher than in sunlit leaves. Additionally, the highly decoupled interface (Ω>0.90) reflected multiple environmental drivers that may influence conductance (e.g. vapor pressure deficit and leaf temperature). This was also seen through large shifts of diurnal peaks of gs and gc (up to 2 hours earlier than Ec) associated with the daily variation of air temperature and net radiation. Overall, this study led to three major insights: 1) gc and gs cannot accurately be predicted under wet conditions without accounting for leaf wetness, 2) even during dry days, low vapor pressure deficits interfere with model accuracy, and 3) intermittent rain during semi-dry and wet days cause large fluctuations in gc and gs estimates. Thus, it

  13. Predicting tropical plant physiology from leaf and canopy spectroscopy.

    Science.gov (United States)

    Doughty, Christopher E; Asner, Gregory P; Martin, Roberta E

    2011-02-01

    A broad regional understanding of tropical forest leaf photosynthesis has long been a goal for tropical forest ecologists, but it has remained elusive due to difficult canopy access and high species diversity. Here we develop an empirical model to predict sunlit, light-saturated, tropical leaf photosynthesis using leaf and simulated canopy spectra. To develop this model, we used partial least squares (PLS) analysis on three tropical forest datasets (159 species), two in Hawaii and one at the biosphere 2 laboratory (B2L). For each species, we measured light-saturated photosynthesis (A), light and CO(2) saturated photosynthesis (A(max)), respiration (R), leaf transmittance and reflectance spectra (400-2,500 nm), leaf nitrogen, chlorophyll a and b, carotenoids, and leaf mass per area (LMA). The model best predicted A [r(2) = 0.74, root mean square error (RMSE) = 2.9 μmol m(-2) s(-1))] followed by R (r(2) = 0.48), and A(max) (r(2) = 0.47). We combined leaf reflectance and transmittance with a canopy radiative transfer model to simulate top-of-canopy reflectance and found that canopy spectra are a better predictor of A (RMSE = 2.5 ± 0.07 μmol m(-2) s(-1)) than are leaf spectra. The results indicate the potential for this technique to be used with high-fidelity imaging spectrometers to remotely sense tropical forest canopy photosynthesis.

  14. CANOPY STRUCTURE AND DEPOSITION EFFICIENCY OF VINEYARD SPRAYERS

    Directory of Open Access Journals (Sweden)

    Gianfranco Pergher

    2007-06-01

    Full Text Available A field study was performed to analyse how deposition efficiency from an axial-fan sprayer was affected by the canopy structure of vines trained to the High Cordon, Low Cordon and Casarsa systems, at beginning of flowering and beginning of berry touch growth stages. An empirical calibration method, providing a dose rate adjustment roughly proportional to canopy height, was used. The canopy structure was assessed using the Point Quadrat method, and determining the leaf area index (LAI and the leaf layer index (LLI. Spray deposits were measured by colorimetry, using a water soluble dye (Tartrazine as a tracer. Correlation between deposits and canopy parameters were analysed and discussed. Foliar deposits per unit leaf area were relatively constant, suggesting that empirical calibration can reduce deposit variability associated with different training systems and growth stages. Total foliar deposition ranged from 33.6% and 82.3% of total spray volume, and increased proportionally with the LLI up to LLI<4. Deposits on bunches significantly decreased with the LLI in the grape zone. The results suggest that sprayer efficiency is improved by a regular, symmetrical canopy, with few leaf layers in the grape zone as in Low Cordon. However, a LLI<3 over the whole canopy and >40% gaps in the foliage both reduced total deposition, and may increase the risk for larger drift losses.

  15. Improvement of Shade Resilience in Photovoltaic Modules Using Buck Converters in a Smart Module Architecture

    Directory of Open Access Journals (Sweden)

    S. Zahra Mirbagheri Golroodbari

    2018-01-01

    Full Text Available Partial shading has a nonlinear effect on the performance of photovoltaic (PV modules. Different methods of optimizing energy harvesting under partial shading conditions have been suggested to mitigate this issue. In this paper, a smart PV module architecture is proposed for improvement of shade resilience in a PV module consisting of 60 silicon solar cells, which compensates the current drops caused by partial shading. The architecture consists of groups of series-connected solar cells in parallel to a DC-DC buck converter. The number of cell groups is optimized with respect to cell and converter specifications using a least-squares support vector machine method. A generic model is developed to simulate the behavior of the smart architecture under different shading patterns, using high time resolution irradiance data. In this research the shading patterns are a combination of random and pole shadows. To investigate the shade resilience, results for the smart architecture are compared with an ideal module, and also ordinary series and parallel connected architectures. Although the annual yield for the smart architecture is 79.5% of the yield of an ideal module, we show that the smart architecture outperforms a standard series connected module by 47%, and a parallel architecture by 13.4%.

  16. Characterization of cocoa production, income diversification and shade tree management along a climate gradient in Ghana

    Science.gov (United States)

    Jassogne, Laurence; Graefe, Sophie; Asare, Richard; Van Asten, Piet; Läderach, Peter; Vaast, Philippe

    2018-01-01

    Reduced climatic suitability due to climate change in cocoa growing regions of Ghana is expected in the coming decades. This threatens farmers’ livelihood and the cocoa sector. Climate change adaptation requires an improved understanding of existing cocoa production systems and farmers’ coping strategies. This study characterized current cocoa production, income diversification and shade tree management along a climate gradient within the cocoa belt of Ghana. The objectives were to 1) compare existing production and income diversification between dry, mid and wet climatic regions, and 2) identify shade trees in cocoa agroforestry systems and their distribution along the climatic gradient. Our results showed that current mean cocoa yield level of 288kg ha-1yr-1 in the dry region was significantly lower than in the mid and wet regions with mean yields of 712 and 849 kg ha-1 yr-1, respectively. In the dry region, farmers diversified their income sources with non-cocoa crops and off-farm activities while farmers at the mid and wet regions mainly depended on cocoa (over 80% of annual income). Two shade systems classified as medium and low shade cocoa agroforestry systems were identified across the studied regions. The medium shade system was more abundant in the dry region and associated to adaptation to marginal climatic conditions. The low shade system showed significantly higher yield in the wet region but no difference was observed between the mid and dry regions. This study highlights the need for optimum shade level recommendation to be climatic region specific. PMID:29659629

  17. Interior shadings for office indoor visual comfort in humid climate region

    Science.gov (United States)

    Dinapradipta, Asri; Sudarma, Erwin; Defiana, Ima; Erwindi, Collinthia

    2018-03-01

    As part of the fenestration system, the interior shadings have also a role to control the indoor environment to maintain indoor visual comfort. As the occupants have personal access to control these, their control behavior then, might enhance or even worsen indoor comfort performance. The controlling behavior might not only influence indoor comfort performance but can also indicate the success or failure of interior shading as a control device element. This paper is intended to report control behavior patterns, as represented by the variety of the slats’ openings of two types of interior shading i.e. Venetian and Vertical blinds and to analyze these on the concurrent impacts to indoor office building’s indoor illuminance and luminance distribution. The purpose of this research is to figure out the shading control patterns as well as to examine the effectiveness of these two types of interior shadings to control indoor visual environment. This study is a quantitative research using experimentation on the slats’ opening of two types of shadings at two identical office rooms. The research results suggested that both types of blinds seem unsuitable for gaining proper illumination values at work planes in humid tropics area. However, these shadings demonstrate good performance for luminance distribution except for that of the closed Venetian blinds.

  18. Morphophysiological Behavior and Cambial Activity in Seedlings of Two Amazonian Tree Species under Shade

    Directory of Open Access Journals (Sweden)

    Monyck Jeane dos Santos Lopes

    2015-01-01

    Full Text Available Variations in light intensity can lead to important anatomical and morphophysiological changes in plants. Aiming to increase knowledge about the Amazonian tree species, this study examines the influence of shade on the cambial activity and development of Parkia gigantocarpa Ducke and Schizolobium parahyba var. amazonicum (Huber ex Ducke Barneby seedlings. Seedlings of the two species were grown in a nursery under four shade intensities (treatments: full sun, low, moderate, and high shade (resp., 0%, 23%, 67%, and 73% of shade, or 2000, 1540, 660, and 540 µmol·m−2·s−1 obtained with polyethylene screens. We measured plant height, stem diameter, biomass production, stomatal conductance (gs, transpiration (E, photosynthesis (A, and cambial activity (CA (xylem, cambium, and phloem. Also, we calculated the Dickson Quality Index (DQI. The highest values of biomass production, gs,  E, A, and DQI, were found under full sun, in P. gigantocarpa, and under low shade intensity in S. parahyba. In both species high shade intensity reduced CA. We concluded that the CA and the physiological and morphological attributes work together, explaining the radial growth and increasing seedlings quality, which optimized efficient seedling production under full sun, in P. gigantocarpa, and under low shade intensity in S. parahyba.

  19. Initial growth of Bauhinia variegata trees under different colored shade nets and light conditions

    Directory of Open Access Journals (Sweden)

    Renata Bachin Mazzini-Guedes

    2014-12-01

    Full Text Available Bauhinia variegata and B. variegata var. candida, commonly known as orchid trees, are small sized trees widely used for urban forestry and landscaping. Adult plants grow under full sun; in Brazil, however, seedlings are generally cultivated in commercial nurseries under natural half-shading. The objective of this study was to evaluate the influence of different colored shade nets and light conditions on the initial growth of B. variegata and B. variegata var. candida. The influence of six light conditions (red net with 50% shading; blue net with 50% shading; black net with 70% shading; black net with 50% shading; black net with 30% shading; and full sun on the initial growth of B. variegata and B. variegata var. candida were evaluated along 160 days, and growth relationships were calculated. Seedlings showed more efficiency on the use of photoassimilated compounds when grown under full sun. Such condition is the most appropriate for seedling production of B. variegata and B. variegata var. candida, contradicting what has been performed in practice.

  20. Response of Artemisia annua L. to shade and manure fertilizer application in lowland altitude

    Science.gov (United States)

    Permana, H. H.; Widyastuti, Y.; Samanhudi; Yunus, A.

    2018-03-01

    Artemisia is a plant producing artemisinin substance which is the main compound in the treatment of malaria. Artemisia comes from China, usually grows wild in native habitats in the plains with an altitude of 1,000-1,500 meters above the sea level. Artemisia development efforts in Indonesia hampered by limited land with the required altitude due to their competition with vegetable crops. Based on this reason, this research is conducted to observe the growth of artemisia planted in lowland with the help of shade and manure. This study aims to determine the level of shade and best manure on the growth of Artemisia. Research conducted at the Laboratory of the Faculty of Agriculture UNS Jumantono using nested design with two factors, shade as main factor and manure fertilizer as sub factor. The data analysis used F test with confidence level of 5%, if significant, then continued with DMRT (Duncan Multiple Range Test). The results showed the treatment of shade gave no difference in growth within 50% shade, 75% shade as well as without shade treatment. Goat manure fertilizer gave the highest result and able to increase plant height, number of branches, flower weight and root volume.

  1. Growth and bromatological characteristics of Brachiaria decumbens and Brachiaria ruziziensis under shading and nitrogen

    Directory of Open Access Journals (Sweden)

    Bruna Moscat Faria

    Full Text Available ABSTRACT This study aimed to evaluate the productive and qualitative characteristics of Brachiaria decumbens and Brachiaria ruziziensis subjected to three levels of artificial shading (0, 36 and 54% and four nitrogen (N doses (0; 50; 100 and 150 mg dm-3 soil, using completely randomized design with a factorial scheme 2 x 3 x 4, with three replications. The dry matter production (DMP, the number of tillers per pot, root weight and crude protein (CP and neutral detergent fiber (NDF contents were evaluated. Both grasses responded quadractly to N, but B. ruziziensis presented greater production under the two highest N doses. The tillers density increased with N dose and was reduced under shading. The root weight increased with N dose, linearly in the full sun and quadractly in the shade. The shading and N showed a positive influence on CP contents. For NDF content, was observed reduction with increase of N dose. The NDF content of B. decumbens increased with shading levels; for B. ruziziensis, the greatest value was observed under intermediate shading level. The N fertilization is an important strategy to improve DMP, tillers density and CP content, for both grasses. However, intense shading should be avoided, as it reduces tillering and root weight, which may threat pasture persistence.

  2. Application of a digital technique in evaluating the reliability of shade guides.

    Science.gov (United States)

    Cal, E; Sonugelen, M; Guneri, P; Kesercioglu, A; Kose, T

    2004-05-01

    There appears to be a need for a reliable method for quantification of tooth colour and analysis of shade. Therefore, the primary objective of this study was to show the applicability of graphic software in colour analysis and secondly to investigate the reliability of commercial shade guides produced by the same manufacturer, using this digital technique. After confirming the reliability and reproducibility of the digital method by using self-assessed coloured images, three shade guides of the same manufacturer were photographed in daylight and in studio environments with a digital camera and saved in tagged image file format (TIFF) format. Colour analysis of each photograph was performed using the Adobe Photoshop 4.0 graphic program. Luminosity, and red, green, blue (L and RGB) values of each shade tab of each shade guide were measured and the data were subjected to statistical analysis using the repeated measure Anova test. The L and RGB values of the images taken in daylight differed significantly from those of the images taken in studio environment (P < 0.05). In both environments, the luminosity and red values of the shade tabs were significantly different from each other (P < 0.05). It was concluded that, when the environmental conditions were kept constant, the Adobe Photoshop 4.0 colour analysis program could be used to analyse the colour of images. On the other hand, the results revealed that the accuracy of shade tabs widely being used in colour matching should be readdressed.

  3. Determining the energy performance of manually controlled solar shades: A stochastic model based co-simulation analysis

    International Nuclear Information System (INIS)

    Yao, Jian

    2014-01-01

    Highlights: • Driving factor for adjustment of manually controlled solar shades was determined. • A stochastic model for manual solar shades was constructed using Markov method. • Co-simulation with Energyplus was carried out in BCVTB. • External shading even manually controlled should be used prior to LOW-E windows. • Previous studies on manual solar shades may overestimate energy savings. - Abstract: Solar shading devices play a significant role in reducing building energy consumption and maintaining a comfortable indoor condition. In this paper, a typical office building with internal roller shades in hot summer and cold winter zone was selected to determine the driving factor of control behavior of manual solar shades. Solar radiation was determined as the major factor in driving solar shading adjustment based on field measurements and logit analysis and then a stochastic model for manually adjusted solar shades was constructed by using Markov method. This model was used in BCVTB for further co-simulation with Energyplus to determine the impact of the control behavior of solar shades on energy performance. The results show that manually adjusted solar shades, whatever located inside or outside, have a relatively high energy saving performance than clear-pane windows while only external shades perform better than regularly used LOW-E windows. Simulation also indicates that using an ideal assumption of solar shade adjustment as most studies do in building simulation may lead to an overestimation of energy saving by about 16–30%. There is a need to improve occupants’ actions on shades to more effectively respond to outdoor conditions in order to lower energy consumption, and this improvement can be easily achieved by using simple strategies as a guide to control manual solar shades

  4. Repressive Tolerance

    DEFF Research Database (Denmark)

    Pedersen, Morten Jarlbæk

    2017-01-01

    Consultation of organised interests and others when drafting laws is often seen as an important source of both input and output legitimacy. But whereas the input side of the equation stems from the very process of listening to societal actors, output legitimacy can only be strengthened if consult......Consultation of organised interests and others when drafting laws is often seen as an important source of both input and output legitimacy. But whereas the input side of the equation stems from the very process of listening to societal actors, output legitimacy can only be strengthened...... a substantial effect on the substance of laws – shows that there is a great difference in the amenability of different branches of government but that, in general, authorities do not listen much despite a very strong consultation institution and tradition. A suggestion for an explanation could be pointing...... to an administrative culture of repressive tolerance of organised interests: authorities listen but only reacts in a very limited sense. This bears in it the risk of jeopardising the knowledge transfer from societal actors to administrative ditto thus harming the consultation institutions’ potential for strengthening...

  5. Effect of Shading on Physiological, Biochemical and Behaviour Changes in Crossbred Calves Under Hot Climatic Conditions

    International Nuclear Information System (INIS)

    Teama, F.E.I.; Gad, A.E.; El-Tarabany, A.A.

    2012-01-01

    The purpose of this study was to investigate the importance and the effect of shading and non-shading house on physiological changes, body weight (BW), average daily gain (ADG), total antioxidant and thyroid hormones in crossbred calves under hot conditions. Thirty six growing crossbred calves (Friesian x Baladi) aged 8-10 months were divided into two groups (each 18 calves); the first group was maintained in shaded house and the second in house without shade (climatic house). The period of study was 79 days during hot conditions. Performance variables (BW, ADG) were measured and the blood samples were collected to assess some biochemical parameters including antioxidants such as total antioxidant (TA), catalase (CAT), total protein, thyroid hormones (T3, T4) and immunoglobulin factor (IgG). Respiration rates and behaviour parameters (feeding, drinking, standing, lying and agonistic) were also measured during the study. The data indicated that the shaded calves had higher ADG (P<0.05) and final BW than non-shaded ones. Also, a significant improvement in total protein levels and globulins were recorded in shaded house calves as compared to non-shaded ones. The same result was obtained for T3 level whereas non-significant changes were observed for T4 level as well as the level of IgG at different times. The present data indicated that using shaded house will decrease the effect of heat stress on calves which will increase the animal performance through improving BW and ADG as well as some biochemical parameters in addition to T3 hormonal level.

  6. Influence of resin cement shade on the color and translucency of ceramic veneers

    Science.gov (United States)

    HERNANDES, Daiana Kelly Lopes; ARRAIS, Cesar Augusto Galvão; de LIMA, Erick; CESAR, Paulo Francisco; RODRIGUES, José Augusto

    2016-01-01

    ABSTRACT Objective This in vitro study evaluated the effect of two different shades of resin cement (RC- A1 and A3) layer on color change, translucency parameter (TP), and chroma of low (LT) and high (HT) translucent reinforced lithium disilicate ceramic laminates. Material and Methods One dual-cured RC (Variolink II, A1- and A3-shade, Ivoclar Vivadent) was applied to 1-mm thick ceramic discs to create thin RC films (100 µm thick) under the ceramics. The RC was exposed to light from a LED curing unit. Color change (ΔE) of ceramic discs was measured according to CIEL*a*b* system with a standard illuminant D65 in reflectance mode in a spectrophotometer, operating in the light range of 360-740 nm, equipped with an integrating sphere. The color difference between black (B) and white (W) background readings was used for TP analysis, while chroma was calculated by the formula C* ab=(a*2+b*2)½. ΔE of 3.3 was set as the threshold of clinically unacceptable. The results were evaluated by two-way ANOVA followed by Tukey's post hoc test. Results HT ceramics showed higher ΔE and higher TP than LT ceramics. A3-shade RC promoted higher ΔE than A1-shade cement, regardless of the ceramic translucency. No significant difference in TP was noted between ceramic discs with A1- and those with A3-shade cement. Ceramic with underlying RC showed lower TP than discs without RC. HT ceramics showed lower chroma than LT ceramics, regardless of the resin cement shade. The presence of A3-shade RC resulted in higher chroma than the presence of A1-shade RC. Conclusions Darker underlying RC layer promoted more pronounced changes in ceramic translucency, chroma, and shade of high translucent ceramic veneers. These differences may not be clinically differentiable. PMID:27556211

  7. Influence of resin cement shade on the color and translucency of ceramic veneers

    Directory of Open Access Journals (Sweden)

    Daiana Kelly Lopes HERNANDES

    Full Text Available ABSTRACT Objective This in vitro study evaluated the effect of two different shades of resin cement (RC- A1 and A3 layer on color change, translucency parameter (TP, and chroma of low (LT and high (HT translucent reinforced lithium disilicate ceramic laminates. Material and Methods One dual-cured RC (Variolink II, A1- and A3-shade, Ivoclar Vivadent was applied to 1-mm thick ceramic discs to create thin RC films (100 µm thick under the ceramics. The RC was exposed to light from a LED curing unit. Color change (ΔE of ceramic discs was measured according to CIEL*a*b* system with a standard illuminant D65 in reflectance mode in a spectrophotometer, operating in the light range of 360-740 nm, equipped with an integrating sphere. The color difference between black (B and white (W background readings was used for TP analysis, while chroma was calculated by the formula C*ab=(a*2+b*2½. ΔE of 3.3 was set as the threshold of clinically unacceptable. The results were evaluated by two-way ANOVA followed by Tukey's post hoc test. Results HT ceramics showed higher ΔE and higher TP than LT ceramics. A3-shade RC promoted higher ΔE than A1-shade cement, regardless of the ceramic translucency. No significant difference in TP was noted between ceramic discs with A1- and those with A3-shade cement. Ceramic with underlying RC showed lower TP than discs without RC. HT ceramics showed lower chroma than LT ceramics, regardless of the resin cement shade. The presence of A3-shade RC resulted in higher chroma than the presence of A1-shade RC. Conclusions Darker underlying RC layer promoted more pronounced changes in ceramic translucency, chroma, and shade of high translucent ceramic veneers. These differences may not be clinically differentiable.

  8. Vegetative and productive aspects of organically grown coffee cultivars under shaded and unshaded systems

    Directory of Open Access Journals (Sweden)

    Marta dos Santos Freire Ricci

    2011-08-01

    Full Text Available Although Coffea arabica species has its origin in the African understories, there is great resistance on the part of the Brazilian producers for growing this species under agroforestry systems as they fear that shading reduces production. This study aimed at evaluating some vegetative traits and the productivity of organically grown coffee (Coffea arabica L. cultivars under shaded and unshaded systems. Twelve treatments consisting of two cultivation systems (shaded and unshaded and six coffee cultivars were arranged in randomized blocks with four replicates, in a split-plot scheme. Shading was provided by banana (Musa sp. and coral bean plants (Erythrinaverna. Shading delayed fruit maturation. Late maturation cultivars, such as the Icatu and the Obatã, matured early in both cultivation systems, while medium and early maturation cultivars presented late maturation. Cultivation in the shaded system increased the leaf area and the number of lower branches, decreased the number of productive nodes per branch, and increased the distance between the nodes and the number of leaves present in the branches. Cultivation in the unshaded system presented greater number of plants with branch blight in relation to plants grown in the shade. The productivity of the cultivars was not different, at 30.0 processed bags per hectare in the shaded system, and 25.8 processed bags per hectare in the unshaded system. The most productive cultivars in the shaded system were the Tupi, the Obatã, and the Catuaí, while no differences between cultivars were obtained in the unshaded system.

  9. Influence of resin cement shade on the color and translucency of ceramic veneers.

    Science.gov (United States)

    Hernandes, Daiana Kelly Lopes; Arrais, Cesar Augusto Galvão; Lima, Erick de; Cesar, Paulo Francisco; Rodrigues, José Augusto

    2016-01-01

    This in vitro study evaluated the effect of two different shades of resin cement (RC- A1 and A3) layer on color change, translucency parameter (TP), and chroma of low (LT) and high (HT) translucent reinforced lithium disilicate ceramic laminates. One dual-cured RC (Variolink II, A1- and A3-shade, Ivoclar Vivadent) was applied to 1-mm thick ceramic discs to create thin RC films (100 µm thick) under the ceramics. The RC was exposed to light from a LED curing unit. Color change (ΔE) of ceramic discs was measured according to CIEL*a*b* system with a standard illuminant D65 in reflectance mode in a spectrophotometer, operating in the light range of 360-740 nm, equipped with an integrating sphere. The color difference between black (B) and white (W) background readings was used for TP analysis, while chroma was calculated by the formula C*ab=(a*2+b*2)½. ΔE of 3.3 was set as the threshold of clinically unacceptable. The results were evaluated by two-way ANOVA followed by Tukey's post hoc test. HT ceramics showed higher ΔE and higher TP than LT ceramics. A3-shade RC promoted higher ΔE than A1-shade cement, regardless of the ceramic translucency. No significant difference in TP was noted between ceramic discs with A1- and those with A3-shade cement. Ceramic with underlying RC showed lower TP than discs without RC. HT ceramics showed lower chroma than LT ceramics, regardless of the resin cement shade. The presence of A3-shade RC resulted in higher chroma than the presence of A1-shade RC. Darker underlying RC layer promoted more pronounced changes in ceramic translucency, chroma, and shade of high translucent ceramic veneers. These differences may not be clinically differentiable.

  10. Forest canopy water fluxes can be estimated using canopy structure metrics derived from airborne light detection and ranging (LiDAR)

    DEFF Research Database (Denmark)

    Schumacher, Johannes; Christiansen, Jesper Riis

    2015-01-01

    Forests contribute to improve water quality, affect drinking water resources, and therefore influence water supply on a regional level. The forest canopy structure affects the retention of precipitation (Pr) in the canopy and hence the amount of water transferred to the forest floor termed canopy...... impacts water resources on a large scale in regions where forests play a major role in water resource management....

  11. Heat loads of transparent construction elements and sun shading systems; Waermelasten transparenter Bauteile und Sonnenschutzsysteme

    Energy Technology Data Exchange (ETDEWEB)

    Simmler, H; Binder, B; Vonbank, R

    2000-07-01

    This report for the Swiss Federal Office of Energy (SFOE) describes a test system installed at the Swiss Federal Laboratories for Materials Testing and Research (EMPA) in Duebendorf, Switzerland, for the investigation of heat gain by glazing elements often used in modern architecture and the efficiency of shading elements. The two climatically controlled test cells for the measurement of the thermal characteristics of facade elements and shading systems are described and the results of measurements made using various types of glazing and shading systems - including external and internal lamellas, blinds and extendible fabric sunshades - are presented. The results are analysed and interpreted in a comprehensive appendix.

  12. Partial Shading Detection in Solar System Using Single Short Pulse of Load

    Directory of Open Access Journals (Sweden)

    Bartczak Mateusz

    2017-03-01

    Full Text Available A single photovoltaic panel under uniform illumination has only one global maximum power point, but the same panel in irregularly illuminated conditions can have more maxima on its power-voltage curve. The irregularly illuminated conditions in most cases are results of partial shading. In the work a single short pulse of load is used to extract information about partial shading. This information can be useful and can help to make some improvements in existing MPPT algorithms. In the paper the intrinsic capacitance of a photovoltaic system is used to retrieve occurrence of partial shading.

  13. Integrated control of sun shades, daylight and artificial light; Integreret regulering af solafskaermning, dagslys og kunstlys

    Energy Technology Data Exchange (ETDEWEB)

    Johnsen, K.; Christoffersen, J.; Soerensen, Henrik; Jessen, G.

    2011-07-01

    The project established a basis of calculation and a practical basis for optimum choice of solar shading and integrated control strategies for both new buildings and for office, commercial and institutional buildings to be renovated with new calculation models for controlling solar shading integrated in the BSim program. A complete and applicable model for optimum, integrated solar shading control was established, focusing on thermal and visual comfort criteria towards energy consumption for heating, cooling and lighting. A prototype was tested in the daylight laboratory at Danish Building Research Institute-Aalborg University and at University of Southern Denmark. (LN)

  14. Colour parameters and shade correspondence of CAD-CAM ceramic systems.

    Science.gov (United States)

    Della Bona, Alvaro; Pecho, Oscar E; Ghinea, Razvan; Cardona, Juan C; Pérez, María M

    2015-06-01

    To evaluate colour differences between (1) CAD-CAM ceramic systems considering shades A1, A2 and A3 and the corresponding nominal shade of VC (Vita Classical shade guide) and (2) shades A1-A2, A2-A3 and A1, A2 and A3 within the same ceramic system. Samples of shades A1, A2 and A3 were fabricated (n=5) from CAD-CAM ceramic blocks (IPS e.max(®) CAD LT and HT, IPS Empress(®) CAD LT and HT, Paradigm™ C, and VITABLOCS(®) Mark II) and polished to 1.0±0.01mm in thickness. Spectral reflectance and colour coordinates were measured using a spectroradiometer inside a viewing booth using the CIE D65 illuminant and the d/0° geometry. Spectral reflectance curves were compared using VAF coefficient and were statistically analyzed using Kruskal-Wallis and the Mann-Whitney U test (α=0.05). Colour coordinates were statistically analyzed using one-way ANOVA, Tukey's test with Bonferroni correction (α=0.001). All colour differences (ΔEab(*) and ΔE00) were analyzed through comparisons with the PT - perceptibility and AT - acceptability thresholds for dental ceramics. ΔE between ceramic systems and its corresponding shade ranged from 6.32 to 13.42 (ΔEab(*)) and 4.48 to 9.30 (ΔE00). ΔE between shades A1-A2, A2-A3 and A1, A2 and A3 ranged, respectively, 1.93-4.82, 1.22-5.59 and 3.63-8.84 (ΔEab(*)); 1.54-3.87, 1.03-3.90 and 2.95-6.51 (ΔE00). Considering the corresponding nominal shade from VC, none of the ceramic systems showed colour differences below the AT. In addition, some ceramic systems showed colour differences below AT (shades A1-A2 and A2-A3) and below PT (shades A2-A3). Careful adjustments should be made to the final shade of CAD-CAM ceramic restorations to reach a clinically acceptable shade match. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Potential Nitrification and Nitrogen Mineral of Soil in Coffee Agroforestry System with Various Shading Trees

    Directory of Open Access Journals (Sweden)

    Purwanto .

    2007-05-01

    Full Text Available The role of shading trees in coffee farms has been well understood to establish suitable condition for the growth of coffee trees, on the other hand their role in nitrogen cycle in coffee farming is not yet well understood. The objectives of this study are to investigate the influence of various legume shading trees on the concentration of soil mineral N (N-NH4 + and N-NO3-, potential nitrification and to study the controlling factors of nitrification under field conditions. This field explorative research was carried out in Sumberjaya, West Lampung. Twelve observation plots covered four land use systems (LUS, i.e. 1 Coffee agroforestry with Gliricidiasepium as shade trees; 2 Coffee agroforestry with Gliricidiaas shade trees and Arachis pintoias cover crops; 3Coffee agroforestry with Paraserianthes falcataria as shade trees; and 4 Mixed/multistrata coffee agroforestry with Gliricidiaand other fruit crops as shade trees. Measurements of soil mineral-N concentration were carried out every three weeks for three months. Results showed that shade tree species in coffee agroforestry significantly affected concentrations of soil NH4 +, NO3- and potential nitrification. Mixed coffee agroforestry had the highest NH4+/N-mineral ratio (7.16% and the lowest potential nitrification (0.13 mg NO2-kg-1 hour -1 compared to other coffee agroforestry systems using single species of leguminous shade trees. Ratio of NH4 + /N-mineral increased 0.8—21% while potential nitrification decreased 55—79% in mixed coffee agroforestry compared to coffee agroforestry with Gliricidia or P. falcatariaas shade trees. Coffee agroforestry with P. falcatariaas shade trees had potential nitrification 53% lower and ratio of NH4 + /N-mineral concentration 20% higher than that with Gliricidia. Coffee agroforestry with P. falcataria as shade trees also had organic C content 17% higher, total N 40% higher, available P 112% higher than that with Gliricidia. The presence of A. pintoiin

  16. Potential phytotoxic and shading effects of invasive Fallopia (Polygonaceae taxa on the germination of native dominant species

    Directory of Open Access Journals (Sweden)

    Lenka Moravcová

    2011-08-01

    Full Text Available Two species of knotweeds (genus Fallopia, Polygonaceae, native to Asia (Fallopia sachalinensis, F. japonica and their hybrid (F. ×bohemica belong to the most noxious plant invaders in Europe and exert a high impact on invaded plant communities that are therefore typically extremely poor in species. The remarkable paucity of invaded communities points to the possible existence of mechanisms suppressing germinating populations of native species in invaded stands. In this pilot study we assessed, under laboratory conditions, whether there are phytotoxic effects of the three Fallopia congeners on seed germination of three target species: two native species commonly growing in habitats that are often invaded by knotweeds (Urtica dioica, Calamagrostis epigejos, and Lepidium sativum, a species commonly used in allelopathic bioassay as a control. Since knotweeds generally form stands with a high cover, we included varying light conditions as an additional factor, to simulate the effects on germination of shading by leaf canopy. The effects of aqueous extracts (2.5, 5.0%, and 0% as a control from dry leaves and rhizomes of the Fallopia congeners on germination of the target species were thus studied under two light regimes, simulating full daylight (white light and light filtered through canopy (green light, and in dark as a control regime. Rhizome extracts did not affect germination. Light treatments yielded inconclusive results, indicating that poor germination and establishment of species in invaded stands is unlikely to be caused by shading alone, but we found a pronounced phytotoxic effect of leaf extracts of Fallopia taxa, more so at 5.0% than 2.5% extract concentration. Fallopia sachalinensis exerted the largest negative effect on the germination of Urtica dioica, F. ×bohemica on that of C.epigejos, and F. japonica had invariably the lowest inhibitory effect. In the field in Central Europe, F. sachalinensis often invades less disturbed, moist

  17. Modelling basin-wide variations in Amazon forest productivity – Part 1: Model calibration, evaluation and upscaling functions for canopy photosynthesis

    Directory of Open Access Journals (Sweden)

    L. M. Mercado

    2009-07-01

    Full Text Available Given the importance of Amazon rainforest in the global carbon and hydrological cycles, there is a need to parameterize and validate ecosystem gas exchange and vegetation models for this region in order to adequately simulate present and future carbon and water balances. In this study, a sun and shade canopy gas exchange model is calibrated and evaluated at five rainforest sites using eddy correlation measurements of carbon and energy fluxes.

    Results from the model-data evaluation suggest that with adequate parameterisation, photosynthesis models taking into account the separation of diffuse and direct irradiance and the dynamics of sunlit and shaded leaves can accurately represent photosynthesis in these forests. Also, stomatal conductance formulations that only take into account atmospheric demand fail to correctly simulate moisture and CO2 fluxes in forests with a pronounced dry season, particularly during afternoon conditions. Nevertheless, it is also the case that large uncertainties are associated not only with the eddy correlation data, but also with the estimates of ecosystem respiration required for model validation. To accurately simulate Gross Primary Productivity (GPP and energy partitioning the most critical parameters and model processes are the quantum yield of photosynthetic uptake, the maximum carboxylation capacity of Rubisco, and simulation of stomatal conductance.

    Using this model-data synergy, we developed scaling functions to provide estimates of canopy photosynthetic parameters for a range of diverse forests across the Amazon region, utilising the best fitted parameter for maximum carboxylation capacity of Rubisco, and foliar nutrients (N and P for all sites.

  18. SRTM Colored Height and Shaded Relief: Corral de Piedra, Argentina

    Science.gov (United States)

    2001-01-01

    Volcanism and erosion are prominently seen in this view of the eastern flank of the Andes Mountains taken by Shuttle Radar Topography Mission (SRTM). The area is southeast of San Martin de Los Andes, Argentina. Eroded peaks up to 2,210-meter-high (7,260-foot) are seen on the west (left), but much of the scene consists of lava plateaus that slope gently eastward. These lava flows were most likely derived from volcanic sources in the high mountains. However, younger and more localized volcanic activity is evident in the topographic data as a cone surrounding oval-shaped flow near the center of the scene.The plateaus are extensively eroded by the Rio Limay (bottom of the image) and the Rio Collon Cura and its tributaries (upper half). The larger stream channels have reached a stable level and are now cutting broad valleys. Few terraces between the levels of the high plateaus and lower valleys (bottom center and upper right of the volcanic cone) indicate that stream erosion had once temporarily reached a higher stable level before eroding down to its current level. In general, depositional surfaces like lava flows are progressively younger with increasing elevation, while erosional surfaces are progressively younger with decreasing elevation.Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear dark, as would be the case at noon at this latitude in the southern hemisphere. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow, red and magenta to white at the highest elevations.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging

  19. New Zealand, SRTM Shaded Relief and Colored Height

    Science.gov (United States)

    2004-01-01

    with the offset in the subduction zone pattern, vertical offsets (about 7 millimeters per year) are likewise consistent with the uplift of the Southern Alps. Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction, so that northwest slopes appear bright and southeast slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations. Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Geospatial-Intelligence Agency (NGA) of the U.S. Department of Defense and the German and Italian space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, Calif., for NASA's Earth Science Enterprise, Washington, D.C. Location: 33.5 to 48 degrees South latitude, 165 to 180 degrees East longitude Orientation: North toward the top, cylindrical projection Image Data: Shaded and colored SRTM elevation model Date Acquired: February 2000

  20. SRTM Colored Height and Shaded Relief: Pinon Canyon region, Colorado

    Science.gov (United States)

    2001-01-01

    Erosional features are prominent in this view of southern Colorado taken by the Shuttle Radar Topography Mission (SRTM). The area covers about 20,000 square kilometers and is located about 50 kilometers south of Pueblo, Colorado. The prominent mountains near the left edge of the image are the Spanish Peaks, remnants of a 20 million year old volcano. Rising 2,100 meters (7,000 ft) above the plains to the east, these igneous rock formations with intrusions of eroded sedimentary rock historically served as guiding landmarks for travelers on the Mountain Branch of the Santa Fe Trail.Near the center of the image is the Pinon Canyon Maneuver Site, a training area for soldiers of the U.S. Army from nearby Fort Carson. The site supports a diverse ecosystem with large numbers of big and small game, fisheries, non-game wildlife, forest, range land and mineral resources. It is bounded on the east by the dramatic topography of the Purgatoire River Canyon, a 100 meter (328 foot) deep scenic red canyon with flowing streams, sandstone formations, and exposed geologic processes.Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction. Southern slopes appear bright and northern slopes appear dark. Color coding is directly related to topographic height, with blue and green at the lower elevations, rising through yellow and brown to white at the highest elevations.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR)that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter

  1. Shaded Relief with Height as Color, Iturralde Structure, Bolivia

    Science.gov (United States)

    2002-01-01

    An 8-kilometer (5-mile) wide crater of possible impact origin is shown in this view of an isolated part of the Bolivian Amazon from the Shuttle Radar Topography Mission. The circular feature at the center-left of the image, known as the Iturralde Structure, is possibly the Earth's most recent 'big' impact event recording collision with a meteor or comet that might have occurred between 11,000 and 30,000 years ago.Although the structure was identified on satellite photographs in the mid-1980s, its location is so remote that it has only been visited by scientific investigators twice, most recently by a team from NASA's Goddard Space Flight Center in September 2002. Lying in an area of very low relief, the landform is a quasi-circular closed depression only about 20 meters (66 feet) in depth, with sharply defined sub-angular 'rim' materials. It resembles a 'cookie cutter' in that its appearance 'cuts' the heavily vegetated soft-sediments and pampas of this part of Bolivia. The SRTM data have provided investigators with the first topographic map of the site and will allow studies of its three-dimensional structure crucial to determining whether it actually is of impact origin.Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction. North-facing slopes appear bright and south-facing slopes appear dark. Color coding is directly related to topographic height, with brown and green at the lower elevations, rising through yellow and brown to white at the highest elevations.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission aboard Space Shuttle Endeavour, launched on Feb. 11, 2000. The mission used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on Endeavour in 1994. The Shuttle Radar Topography Mission was

  2. Pando Province, Northern Bolivia, Shaded Relief and Colored Height

    Science.gov (United States)

    2003-01-01

    Pando Province, Bolivia, and adjacent parts of Brazil and Peru are seen in this visualization of Shuttle Radar Topography Mission (SRTM) elevation data covering part of the Amazon Basin. Most of this region is covered by tropical rainforest and is still largely unaltered by development, though new roads are providing increased access to the area, leading to changes in the landscape. SRTM data provide the first detailed three-dimensional look at the landforms of this region, and the Amazon Basin in its entirety, and will be particularly helpful in understanding the hydrologic patterns as environmental management becomes increasingly important.River drainage across this area flows generally east-northeast away from the nearby Andes Mountains. The most prominent river channels seen here are the Purus River in the northwest (upper left) and the Madre de Dios River, which crosses the south central (lower central) part of this view. The Beni and Mamore Rivers combine with the Madre de Dios in the eastern (right central) area to form the Madeira River, which flows northeast to eventually meet the Amazon River near Manaus.The Trans-Amazon Highway crosses the northern half of the scene, and subtle evidence of rainforest clear cutting, facilitated by this easy access, is apparent just north of the scene center, even at the low resolution of this display (740 m or 2428 feet). As seen here, clear cutting patterns in the rainforest typically show a pattern of parallel lines. SRTM mapped the shape of the Earths solid surface (not exclusively the ground surface), which includes to some degree land covers such as forests. Thus, SRTM data are capable of revealing deforestation patterns.For a smaller, annotated version of this image, please select Figure 1, below: [figure removed for brevity, see original site] (image size: 184k JPEG)A combination of visualization methods was used to produce this image, based on shading and color coding. A shade image was derived by computing

  3. Cuttlefish see shape from shading, fine-tuning coloration in response to pictorial depth cues and directional illumination.

    Science.gov (United States)

    Zylinski, Sarah; Osorio, D; Johnsen, Sonke

    2016-03-16

    Humans use shading as a cue to three-dimensional form by combining low-level information about light intensity with high-level knowledge about objects and the environment. Here, we examine how cuttlefish Sepia officinalis respond to light and shadow to shade the white square (WS) feature in their body pattern. Cuttlefish display the WS in the presence of pebble-like objects, and they can shade it to render the appearance of surface curvature to a human observer, which might benefit camouflage. Here we test how they colour the WS on visual backgrounds containing two-dimensional circular stimuli, some of which were shaded to suggest surface curvature, whereas others were uniformly coloured or divided into dark and light semicircles. WS shading, measured by lateral asymmetry, was greatest when the animal rested on a background of shaded circles and three-dimensional hemispheres, and less on plain white circles or black/white semicircles. In addition, shading was enhanced when light fell from the lighter side of the shaded stimulus, as expected for real convex surfaces. Thus, the cuttlefish acts as if it perceives surface curvature from shading, and takes account of the direction of illumination. However, the direction of WS shading is insensitive to the directions of background shading and illumination; instead the cuttlefish tend to turn to face the light source. © 2016 The Author(s).

  4. San Gabriel Mountains, California, Shaded relief, color as height

    Science.gov (United States)

    2000-01-01

    This topographic image shows the relationship of the urban area of Pasadena, California to the natural contours of the land. The image includes the alluvial plain on which Pasadena and the Jet Propulsion Laboratory sit, and the steep range of the San Gabriel Mountains. The mountain front and the arcuate valley running from upper left to the lower right are active fault zones, along which the mountains are rising. The chaparral-covered slopes above Pasadena are also a prime area for wildfires and mudslides. Hazards from earthquakes, floods and fires are intimately related to the topography in this area. Topographic data and other remote sensing images provide valuable information for assessing and mitigating the natural hazards for cities along the front of active mountain ranges.This shaded relief image was generated using topographic data from the Shuttle Radar Topography Mission. A computer-generated artificial light source illuminates the elevation data to produce a pattern of light and shadows. Slopes facing the light appear bright, while those facing away are shaded. On flatter surfaces, the pattern of light and shadows can reveal subtle features in the terrain. Colors show the elevation as measured by SRTM. Colors range from blue at the lowest elevations to white at the highest elevations. This image contains about 2300 meters (7500 feet) of total relief. White speckles on the face of some of the mountains are holes in the data caused by steep terrain. These will be filled using coverage from an intersecting pass.The Shuttle Radar Topography Mission (SRTM), launched on February 11,2000, uses the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. The mission is designed to collect three-dimensional measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter-long (200-foot) mast, an additional C-band imaging antenna

  5. Shaded Relief with Height as Color, Mount Meru, Tanzania

    Science.gov (United States)

    2002-01-01

    Mount Meru is an active volcano located just 70 kilometers (44 miles) west of Mount Kilimanjaro. It reaches 4,566 meters (14,978 feet) in height but has lost much of its bulk due to an eastward volcanic blast sometime in its distant past, perhaps similar to the eruption of Mount Saint Helens in Washington State in 1980. Mount Meru most recently had a minor eruption about a century ago. The several small cones and craters seen in the vicinity probably reflect numerous episodes of volcanic activity. Mount Meru is the topographic centerpiece of Arusha National Park. Its fertile slopes rise above the surrounding savanna and support a forest that hosts diverse wildlife, including nearly 400 species of birds, and also monkeys and leopards.Two visualization methods were combined to produce this image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear dark, as would be the case at noon at this latitude in June. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow, red, and magenta, to blue and white at the highest elevations.Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense and the German and Italian space

  6. Heat tolerance in Field Grown Tomatoes (Lycopersicon esculentum Mill.) under Semi Arid Conditions of West Africa

    DEFF Research Database (Denmark)

    Kugblenu, Y O; Oppong Danso, E; Ofori, K

    2013-01-01

    One major reason for extremely low production of tomato in Ghana is that the length of the growing season last only for a few months due to the high temperature influx during the remaining months. The temperatures recorded during these months are above the optimum for tomato flowering and fruiting...... and this consequently affects yield. To solve this problem a number management practices may be undertaken such has growing heat tolerant tomato varieties or providing shade to mitigate the devastating effect of high temperatures. Therefore the present study was conducted outside the normal growing season from June...... to October, which has a mean temperature of 23°C. Heat tolerant tomato cultivars were grown from April to July with a mean temperature of 25°C to evaluate their performance under these conditions and to assess the effect of shading on the production of one of the genotypes. Fruiting percentage...

  7. Influence of artificial accelerated aging on the color stability and opacity of composites of different shades.

    Science.gov (United States)

    Mundim, F M; Da Fonseca Roberti Garcia, L; Silva Sousa, A B; Cruvinel, D R; De Carvalho Panzeri Pires-De-Souza, F

    2010-10-01

    The aim of this study was to evaluate the influence of artificial accelerated aging on the color stability and opacity of composites of different shades. Four composites for direct use (Heliomolar, 4 Seasons, Tetric EvoCeram; QuiXfil) and one for indirect use (SR Adoro) in two shades were used: light (A2) and dark (C3 for direct, and D4 for indirect composite). QuiXfil was obtained in Universal shade. A Teflon matrix (12 X 2 mm) was used to obtain 54 specimens (N=6), which were submitted to color and opacity analysis (Spectrophotometer PCB 6807, Byk Gardner) before and after artificial accelerated aging for 384 hours. After the statistical analysis (2-way ANOVA - Bonferroni - PArtificial accelerated aging interfered in the optical properties assessed; however, the alterations seemed to be more related to the composites composition than to their shade.

  8. Differences between the human eye and the spectrophotometer in the shade matching of tooth colour.

    Science.gov (United States)

    Gómez-Polo, Cristina; Gómez-Polo, Miguel; Celemin-Viñuela, Alicia; Martínez Vázquez De Parga, Juan Antonio

    2014-06-01

    The aim of this work was to assess the agreement between instrumental and visual colour matching. Shade selection with the 3DMaster Toothguide (Vita-Zahnfabrik) was performed for 1361 maxillary central incisors and compared with the shade obtained with the EasyShade Compact (Vita-Zahnfabrik) spectrophotometer. We observed a greater correlation between the objective method and the subjective one in the colour dimension of lightness (Kappa 0.6587), followed by hue (Kappa 0.4337) and finally chroma (Kappa 0.3578). The colour dimension in which the greatest agreement is seen between the operator and the spectrophotometer is value or lightness. This study reveals differences between the measurement of colour via spectrophotometry and the visual shade selection method. According to our results, there is better agreement in the value or lightness colour dimension, which is the most important one in the choice of tooth colour. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Assessment of microclimate conditions under artificial shades in a ginseng field

    Directory of Open Access Journals (Sweden)

    Kyu Jong Lee

    2016-01-01

    Conclusion: Weather measurements outside the shade and LWD estimates derived from these measurements would be useful as inputs for decision support systems to predict ginseng growth and disease development.

  10. Effect of shade on various parameters of Friesian cows in a ...

    African Journals Online (AJOL)

    Keywords: Behavioural pattern , dairy cows, heat stress, shade. * Author to whom ... The negative effect of high temperatures, solar radiation, relative humidity and ..... Cattle do nct exhibit true sleep as in humans, except for very short periods.

  11. Multiple Solutions for Reconfiguration to Address Partial Shading Losses in Solar Photovoltaic Arrays

    Science.gov (United States)

    Sharma, Nikesh; Pareek, Smita; Chaturvedi, Nitin; Dahiya, Ratna

    2018-03-01

    Solar photovoltaic (SPV) systems are steadily rising and considered as the best alternatives to meet the rising demand of energy. In developing countries like India, SPV’s contribution being a clean energy is the most favourable. However, experiences have shown that produced power of these systems is usually affected due to day, night, seasonal variations, insolation, partial shading conditions etc. Among these parameters, partial shading causes a huge reduction in output power of PV systems. This results in lack of confidence for this technology among users. Thus, it is important and a major challenge in PV systems to minimize the effect of partial shading on their energy production. The work in this paper aims to propose solutions for reconfiguration of solar photovoltaic arrays in order to reduce partial shading losses and thus to enhance power generation.

  12. Comparative Analysis of Maximum Power Point Tracking Controllers under Partial Shaded Conditions in a Photovoltaic System

    Directory of Open Access Journals (Sweden)

    R. Ramaprabha

    2015-06-01

    Full Text Available Mismatching effects due to partial shaded conditions are the major drawbacks existing in today’s photovoltaic (PV systems. These mismatch effects are greatly reduced in distributed PV system architecture where each panel is effectively decoupled from its neighboring panel. To obtain the optimal operation of the PV panels, maximum power point tracking (MPPT techniques are used. In partial shaded conditions, detecting the maximum operating point is difficult as the characteristic curves are complex with multiple peaks. In this paper, a neural network control technique is employed for MPPT. Detailed analyses were carried out on MPPT controllers in centralized and distributed architecture under partial shaded environments. The efficiency of the MPPT controllers and the effectiveness of the proposed control technique under partial shaded environments was examined using MATLAB software. The results were validated through experimentation.

  13. Duration and intensity of shade differentially affects mycorrhizal growth- and phosphorus uptake responses of Medicago truncatula

    Czech Academy of Sciences Publication Activity Database

    Konvalinková, T.; Püschel, David; Janoušková, Martina; Gryndler, M.; Jansa, J.

    2015-01-01

    Roč. 6, FEB 13 (2015), s. 1-11 ISSN 1664-462X Institutional support: RVO:67985939 Keywords : arbuscular mycorrhizal symbiosis * light intensity * shading duration Subject RIV: EE - Microbiology, Virology Impact factor: 4.495, year: 2015

  14. Shade tree diversity enhances coffee production and quality in agroforestry systems in the Western Ghats

    NARCIS (Netherlands)

    Nesper, Maike; Kueffer, Christoph; Krishnan, Smitha; Kushalappa, Cheppudira G.; Ghazoul, Jaboury

    2017-01-01

    Intensification of multispecies coffee agroforests reduces shade tree diversity with implications for tropical biodiversity. We investigated how tree biodiversity and its effects on coffee production and quality changes along a gradient of intensification (from diverse multispecies to Grevillea

  15. Comparison of shade matching by visual observation and an intraoral dental colorimeter.

    Science.gov (United States)

    Li, Q; Wang, Y N

    2007-11-01

    The purpose of this study was to compare the applicability of two shade-matching approaches: Vintage Halo shade guide (visual method) and Shofu ShadeEye NCC colorimeter (instrumental method). Twenty participants' maxillary left central incisors were evaluated. Corresponding metal ceramic crowns were fabricated with each shade-matching approach. The colour distributions (L*, a* and b*) of the middle third region of each tooth and corresponding metal ceramic crowns were spectrophotometrically assessed. The colour difference (DeltaE) and colour distributions (DeltaL*, Deltaa* and Deltab*) between the tooth and the corresponding crowns were calculated. We found that the colour differences of both groups fell within the clinical unacceptable range (DeltaE > 2.75). Regarding DeltaE and the three colour distributions, no significant difference was found, expect for a* (P colorimeter nor the visual approach. However, the colorimeter can achieve better results within easy matching cases.

  16. [Effects of shading on two Sphagnum species growth and their interactions].

    Science.gov (United States)

    Ma, Jin-Ze; Bu, Zhao-Jun; Zheng, Xing-Xing; Li, Shan-Lin; Zeng, Jing; Zhao, Gao-Lin

    2012-02-01

    Taking Sphagnum palustre and S. fallax as test materials, this paper studied their growth and interactions under shading. In monoculture, shading promoted the height growth of S. palustre markedly, but had no effect on the growth of S. fallax and the biomass and branching of S. palustre. In mixed culture, S. fallax suppressed the increase of biomass and branching of S. palustre, while S. palustre had no effects on S. fallax. With the increase of shading stress, the competition of neighbour on S. fallax intensified. When the stress increased further, neighbor effect on S. fallax tended to be positive. However, the effect of neighbour on S. palustre was always competitive and did not change with the increase of shading stress.

  17. Daylight Adaptive Shading Using Parametric Camshaft Mechanism for SOHO in Jakarta

    Directory of Open Access Journals (Sweden)

    Sjarifudin Firza Utama

    2014-03-01

    Full Text Available This research analyzes SOHO (Small Office Home Office which can adjust to the need of visual comfort for the users through natural daylighting and also can be adapted to standard requirements of 14 creative industry workspace in Jakartas. The method of the research is by simulating the SOHO unit with variation of shading opening angles in order to adapt to each unit. Analysis done to every shading opening angle to get the appropriate daylight intensity level which support the work activities in every unit for the whole day. In order for the shading to be able to adapt to the changing daylight condition, previously developed parametric camshaft mechanism was used. The study found that the visual comfort for SOHO with creative industries workers in Jakarta can be achieve by varying the shading opening angles between 15-75°.

  18. Is shade for horses a comfort resource or a minimum requirement?

    Science.gov (United States)

    Holcomb, K E

    2017-09-01

    Shade or shelter as protection from extremes of weather is required for horses at agricultural research and teaching facilities and is recommended or required by many states, professional organizations, and industry groups. The focus of this paper is the recent research on the responses of horses to hot, sunny weather, which has begun to provide scientific evidence that characterizes how and when shade is used and any benefits shade confers on horses. These behavioral and physiological findings support provision of shade as a resource for thermal comfort and the expression of normal behavior that should be included as a standard of best care practices for healthy adult horses living in the environmental conditions reviewed, rather than an absolute minimum care requirement. Additional research is required for horses living under other environmental conditions, for very young or old horses, horses in very poor body condition, or those with compromised health to determine if their responses to hot, sunny weather differ from those presented here.

  19. Photosynthetic light response of the C4 grasses Brachiaria brizantha and B. humidicola under shade

    Directory of Open Access Journals (Sweden)

    Dias-Filho Moacyr Bernardino

    2002-01-01

    Full Text Available Forage grasses in tropical pastures can be subjected to considerable diurnal and seasonal reductions in available light. To evaluate the physiological behavior of the tropical forage grasses Brachiaria brizantha cv. Marandu and B. humidicola to low light, the photosynthetic light response and chlorophyll contents of these species were compared for plants grown outdoors, on natural soil, in pots, in full sunlight and those shaded to 30 % of full sunlight, over a 30-day period. Both species showed the ability to adjust their photosynthetic behavior in response to shade. Photosynthetic capacity and light compensation point were lower for shade plants of both species, while apparent quantum yield was unaffected by the light regime. Dark respiration and chlorophyll a:b ratio were significantly reduced by shading only in B. humidicola. B. humidicola could be relatively more adapted to succeed, at least temporarily, in light-limited environments.

  20. Effect of shade on various parameters of Friesian cows in a ...

    African Journals Online (AJOL)

    The effect of a shade structure on the feed intake, water intake, milk production and milk composition of Dutch-type ... balance of an animal but does not affect air temperature or .... temperature above this temperature limits reproductive.

  1. Effects of shade and drought stress on soybean hormones and yield ...

    African Journals Online (AJOL)

    Jane

    2011-10-24

    Oct 24, 2011 ... hormone concentrations, main-stem and branch yield response to the combination of shade and drought were studied ... yield primarily by reducing branch growth and branch seed yield per ..... deficit soybean. Yield decrease ...

  2. A Low Cost Shading Analyzer and Site Evaluator Design to Determine Solar Power System Installation Area

    Directory of Open Access Journals (Sweden)

    Selami Kesler

    2015-01-01

    Full Text Available Shading analyzer systems are necessary for selecting the most suitable installation site to sustain enough solar power. Afterwards, changes in solar data throughout the year must be evaluated along with the identification of obstructions surrounding the installation site in order to analyze shading effects on productivity of the solar power system. In this study, the shading analysis tools are introduced briefly, and a new and different device is developed and explained to analyze shading effect of the environmental obstruction on the site on which the solar power system will be established. Thus, exposure duration of the PV panels to the sunlight can be measured effectively. The device is explained with an application on the installation area selected as a pilot site, Denizli, in Turkey.

  3. Simulations of tropical rainforest albedo: is canopy wetness important?

    Directory of Open Access Journals (Sweden)

    Silvia N.M. Yanagi

    Full Text Available Accurate information on surface albedo is essential for climate modelling, especially for regions such as Amazonia, where the response of the regional atmospheric circulation to the changes on surface albedo is strong. Previous studies have indicated that models are still unable to correctly reproduce details of the seasonal variation of surface albedo. Therefore, it was investigated the role of canopy wetness on the simulated albedo of a tropical rainforest by modifying the IBIS canopy radiation transfer code to incorporate the effects of canopy wetness on the vegetation reflectance. In this study, simulations were run using three versions of the land surface/ecosystem model IBIS: the standard version, the same version recalibrated to fit the data of albedo on tropical rainforests and a modified version that incorporates the effects of canopy wetness on surface albedo, for three sites in the Amazon forest at hourly and monthly scales. The results demonstrated that, at the hourly time scale, the incorporation of canopy wetness on the calculations of radiative transfer substantially improves the simulations results, whereas at the monthly scale these changes do not substantially modify the simulated albedo.

  4. Impact of shading on daylight quality. Simulations with radiance

    Energy Technology Data Exchange (ETDEWEB)

    Dubois, M.C.

    2001-07-01

    The impact of six exterior shading devices on daylight quality and on the potential for daylight utilisation in a standard, south-oriented office room was investigated through computer simulations with Radiance. The daylight quality was evaluated by considering four performance indicators: the absolute work plane illuminance, the illuminance uniformity on the work plane, the absolute luminance in the visual field and the luminance ratios between the work plane, VDT screen and surrounding surfaces. The results indicate that the overhang, white awning and horizontal venetian blind generated work plane illuminance levels that are more suitable for offices where traditional tasks are carried out. However, these devices did not prevent high luminance values at the window. On the other hand, the grey specular screen produced unacceptably low work plane illuminance, poor illuminance uniformity and unacceptably low luminance levels which resulted in unsuitable luminance ratios between the VDT screen, work plane and surroundings. The 45 deg venetian blind, white screen and blue awning provided work plane illuminance levels suitable for offices where a combination of paper and computer work is carried out. They also provided acceptable illuminance uniformity on the work plane, suitable luminance ratios between the work plane, VDT screen and surroundings and they significantly reduced the luminance of the window. However, the blue awning had a poorer performance in December than in June and the white screen resulted in high luminance values at the window, which indicates that the best device among the ones studied was the 45 deg venetian blind.

  5. Response of lentil (Lens culinaris Medik.) to artificial shading during the reproductive stage

    International Nuclear Information System (INIS)

    Peñaloza H, Enrique; Díaz S, Jorge

    1997-01-01

    Lentil production in southern Chile is subject to significant seasonal fluctuations in solar radiation received during the reproductive stage, with an average variation ranging from 300 to 650 g cal cm -2 day -1 . to quantify the effect of reducing incident light on crop performance, artifical shading experiments were conducted with 80% light reduction during different periods spanning the reprodcutive stage, as well as various degrees of shading (0, 20, 35, 50 and 80%) throughout. shading was achieved by using a black polypropylene net placed at 0.8 m above soil surface. The experiments were carried out during the 1991/92, 1992/93 and 1993/94 cropping seasons at the Centro Regional de Investigación Carillanca, INIA (38°41' S, 72°25' W). The effect of 80% shading on seed yield was dependent upon the period at which the treatment was imposed. Seed yield reduction was higher when shading occurred during the growth stages R--R5, accounting 35, 48 and 59% yield losses for the 1991/92, 1992/93 and 1993/94 seasons, respectively. No significant diffreences were detected between R1-R3 and R5-R8 periods, with seed yield losses averaging 39 (1991/92), 10 (1992/93) and 25% (1993/94). Variations in seed yield due to shading were explained mainly by a reduction of total pods m -2 and an increase in empty (flat) pods (R3-R5), and a reduction on the average seed weight (R5-R8). As expected, the higher losses occurred on treatments exposed to two (R1-R5, R3-R8) or three (R1-R8) periods of shading. Grain yield under different degrees of shading was significantly reduced, with responses fitted to the functions Y = 2.020-32.5s + 0.18s 2 (1992/93) and Y = 2.172-25.6s-0.04s 2 (1993/94). Reduction on seed yield was associated to a decrease in total pods m -2 and average seed weight, whereas empty pods increased significantly only at near 80% shading. These results point at R3-R5 as the most sensible growth stage under 80% shading and demonstrate the sensitiveness of lentil

  6. Performance assessment of Vita Easy Shade spectrophotometer on colour measurement of aesthetic dental materials.

    Science.gov (United States)

    AlGhazali, N; Burnside, G; Smith, R W; Preston, A J; Jarad, F D

    2011-12-01

    Four different shades were used to produce 20 samples of resin-based composite and 20 samples of porcelain to evaluate the performance ability of an intra oral test spectrophotometer compared to a reference spectrophotometer. The absolute colour coordinates CIELAB values measured with both spectrophotometers were significantly different (p spectrophotometers (p < 0.05). Therefore, the Easy Shade can be used in dental practice and dental research with some limitations.

  7. Photovoltaic Shading Testbed for Module-Level Power Electronics: 2016 Performance Data Update

    Energy Technology Data Exchange (ETDEWEB)

    Deline, Chris [National Renewable Energy Lab. (NREL), Golden, CO (United States); Meydbray, Jenya [PV Evolution Labs (PVEL), Davis, CA (United States); Donovan, Matt [PV Evolution Labs (PVEL), Davis, CA (United States)

    2016-09-01

    The 2012 NREL report 'Photovoltaic Shading Testbed for Module-Level Power Electronics' provides a standard methodology for estimating the performance benefit of distributed power electronics under partial shading conditions. Since the release of the report, experiments have been conducted for a number of products and for different system configurations. Drawing from these experiences, updates to the test and analysis methods are recommended. Proposed changes in data processing have the benefit of reducing the sensitivity to measurement errors and weather variability, as well as bringing the updated performance score in line with measured and simulated values of the shade recovery benefit of distributed PV power electronics. Also, due to the emergence of new technologies including sub-module embedded power electronics, the shading method has been extended to include power electronics that operate at a finer granularity than the module level. An update to the method is proposed to account for these emerging technologies that respond to shading differently than module-level devices. The partial shading test remains a repeatable test procedure that attempts to simulate shading situations as would be experienced by typical residential or commercial rooftop photovoltaic (PV) systems. Performance data for multiple products tested using this method are discussed, based on equipment from Enphase, Solar Edge, Maxim Integrated and SMA. In general, the annual recovery of shading losses from the module-level electronics evaluated is 25-35%, with the major difference between different trials being related to the number of parallel strings in the test installation rather than differences between the equipment tested. Appendix D data has been added in this update.

  8. Effect of late planting and shading on cellulose synthesis during cotton fiber secondary wall development.

    Directory of Open Access Journals (Sweden)

    Ji Chen

    Full Text Available Cotton-rapeseed or cotton-wheat double cropping systems are popular in the Yangtze River Valley and Yellow River Valley of China. Due to the competition of temperature and light resources during the growing season of double cropping system, cotton is generally late-germinating and late-maturing and has to suffer from the coupling of declining temperature and low light especially in the late growth stage. In this study, late planting (LP and shading were used to fit the coupling stress, and the coupling effect on fiber cellulose synthesis was investigated. Two cotton (Gossypium hirsutum L. cultivars were grown in the field in 2010 and 2011 at three planting dates (25 April, 25 May and 10 June each with three shading levels (normal light, declined 20% and 40% PAR. Mean daily minimum temperature was the primary environmental factor affected by LP. The coupling of LP and shading (decreased cellulose content by 7.8%-25.5% produced more severe impacts on cellulose synthesis than either stress alone, and the effect of LP (decreased cellulose content by 6.7%-20.9% was greater than shading (decreased cellulose content by 0.7%-5.6%. The coupling of LP and shading hindered the flux from sucrose to cellulose by affecting the activities of related cellulose synthesis enzymes. Fiber cellulose synthase genes expression were delayed under not only LP but shading, and the coupling of LP and shading markedly postponed and even restrained its expression. The decline of sucrose-phosphate synthase activity and its peak delay may cause cellulose synthesis being more sensitive to the coupling stress during the later stage of fiber secondary wall development (38-45 days post-anthesis. The sensitive difference of cellulose synthesis between two cultivars in response to the coupling of LP and shading may be mainly determined by the sensitiveness of invertase, sucrose-phosphate synthase and cellulose synthase.

  9. Photosynthesis and chlorophyll fluorescence reaction to different shade stresses of weak light sensitive maize

    International Nuclear Information System (INIS)

    Wang, J.; Li, F.; Shi, Z.; Huang, H.; Jia, S.

    2017-01-01

    A split-plot experimental study was conducted to evaluate the effect of different shade stresses on photosynthesis and chlorophyll fluorescence of maize leaves.The experiment was designed on the south farm of Special Corn Institute, Shenyang Agricultural University, China.Data was collected from the day maize tasseled (Jul. 21) to the beginning of grouting (Aug.12 ) under 18%, 28%, 38%, 60%, and 75% shade stress to determine indexes such as photosynthesis and chlorophyll fluorescence after 15 days of shade treatment. Pairs of near-isogenic lines (NILs) of Shennong 98A (a barren stalk inbred line) and Shennong 98B (an un-barren stalk inbred line) were used as experimental materials to further reveal photosynthetic mechanisms of weak light sensitive maize when exposed to weak light conditions. Thus, a foundation was established for high density-resistant (shade resistant) corn breeding,while identifying weak light sensitive varieties. After shading treatment, chlorophyll a and total chlorophyll content of both varieties increased, chlorophyll b content first increased, followed by a decrease, while the net photosynthetic rate and stomatal conductance showed a gradually decreasing trend. The changing trends of photochemical quenching coefficient(qp) and effective quantum yield of PSII photochemistry (FPSII)were similar, FPSII and qP increased significantly as shading stress increased from 18% to 38%;however, FPSII and qP declined significantly under 60% and 75% shading stresses. The changing trend of NPQ was opposite to FPSII and qP. A comparison of both inbred lines showed that photosynthesis and chlorophyll fluorescence characteristics of Shennong 98B were superior to Shennong 98A. This study revealed the relationships between weak light sensitive lines and shade intensities by comparing differences in photosynthesis and chlorophyll fluorescence parameters. (author)

  10. Is shade beneficial for mediterranean shrubs experiencing periods of extreme drought and late-winter frosts?

    Science.gov (United States)

    Valladares, Fernando; Zaragoza-Castells, Joana; Sánchez-Gómez, David; Matesanz, Silvia; Alonso, Beatriz; Portsmuth, Angelika; Delgado, Antonio; Atkin, Owen K

    2008-12-01

    Plants are naturally exposed to multiple, frequently interactive stress factors, most of which are becoming more severe due to global change. Established plants have been reported to facilitate the establishment of juvenile plants, but net effects of plant-plant interactions are difficult to assess due to complex interactions among environmental factors. An investigation was carried out in order to determine how two dominant evergreen shrubs (Quercus ilex and Arctostaphylos uva-ursi) co-occurring in continental, Mediterranean habitats respond to multiple abiotic stresses and whether the shaded understorey conditions ameliorate the negative effects of drought and winter frosts on the physiology of leaves. Microclimate and ecophysiology of sun and shade plants were studied at a continental plateau in central Spain during 2004-2005, with 2005 being one of the driest and hottest years on record; several late-winter frosts also occurred in 2005. Daytime air temperature and vapour pressure deficit were lower in the shade than in the sun, but soil moisture was also lower in the shade during the spring and summer of 2005, and night-time temperatures were higher in the shade. Water potential, photochemical efficiency, light-saturated photosynthesis, stomatal conductance and leaf 13C composition differed between sun and shade individuals throughout the seasons, but differences were species specific. Shade was beneficial for leaf-level physiology in Q. ilex during winter, detrimental during spring for both species, and of little consequence in summer. The results suggest that beneficial effects of shade can be eclipsed by reduced soil moisture during dry years, which are expected to be more frequent in the most likely climate change scenarios for the Mediterranean region.

  11. Representasi Perempuan Dalam Film (Analisis Semiotika Representasi Perempuan Dalam Film “Fifty Shades of Grey”)

    OpenAIRE

    Aviomeita, Friska

    2016-01-01

    This study entitled "Representation of Women In Film ( Roland Barthes Semiotics Analysis In the film Fifty Shades of Grey ) " . The purpose of this study to find out how women are represented in the film " Fifty Shades of Grey " by denotation , connotation and myths . Film has always influenced and shaped the public based on the contents of the message behind it. Messages or values contained in the film may affect the audience. In this study, researchers used several theorie...

  12. Pasture shade and farm management effects on cow productivity in the tropics

    OpenAIRE

    Ainsworth, Justin A.W.; Moe, Stein R.; Skarpe, Christina

    2012-01-01

    This is the postprint version of the article. The published article can be located at the publisher's webpage Shade, provided by trees within pastures, can affect cattle productivity through mitigating heat stress and by altering understorey pasture growth and cattle behaviour. Models for daily milk yield and body condition were used to evaluate the effect of pasture shade on dual purpose cow productivity within a silvopastoral system in a dry tropical province of Nicaragua. Daily milk yie...

  13. In vitro and in vivo evaluations of three computer-aided shade matching instruments.

    Science.gov (United States)

    Yuan, Kun; Sun, Xiang; Wang, Fu; Wang, Hui; Chen, Ji-hua

    2012-01-01

    This study evaluated the accuracy and reliability of three computer-aided shade matching instruments (Shadepilot, VITA Easyshade, and ShadeEye NCC) using both in vitro and in vivo models. The in vitro model included the measurement of five VITA Classical shade guides. The in vivo model utilized three instruments to measure the central region of the labial surface of maxillary right central incisors of 85 people. The accuracy and reliability of the three instruments in these two evaluating models were calculated. Significant differences were observed in the accuracy of instruments both in vitro and in vivo. No significant differences were found in the reliability of instruments between and within the in vitro and the in vivo groups. VITA Easyshade was significantly different in accuracy between in vitro and in vivo models, while no significant difference was found for the other two instruments. Shadepilot was the only instrument tested in the present study that showed high accuracy and reliability both in vitro and in vivo. Significant differences were observed in the L*a*b* values of the 85 natural teeth measured using three instruments in the in vivo assessment. The pair-agreement rates of shade matching among the three instruments ranged from 37.7% to 48.2%, and the incidence of identical shade results shared by all three instruments was 25.9%. As different L*a*b* values and shade matching results were reported for the same tooth, a combination of the evaluated shade matching instruments and visual shade confirmation is recommended for clinical use.

  14. The MODIS Vegetation Canopy Water Content product

    Science.gov (United States)

    Ustin, S. L.; Riano, D.; Trombetti, M.

    2008-12-01

    Vegetation water stress drives wildfire behavior and risk, having important implications for biogeochemical cycling in natural ecosystems, agriculture, and forestry. Water stress limits plant transpiration and carbon gain. The regulation of photosynthesis creates close linkages between the carbon, water, and energy cycles and through metabolism to the nitrogen cycle. We generated systematic weekly CWC estimated for the USA from 2000-2006. MODIS measures the sunlit reflectance of the vegetation in the visible, near-infrared, and shortwave infrared. Radiative transfer models, such as PROSPECT-SAILH, determine how sunlight interacts with plant and soil materials. These models can be applied over a range of scales and ecosystem types. Artificial Neural Networks (ANN) were used to optimize the inversion of these models to determine vegetation water content. We carried out multi-scale validation of the product using field data, airborne and satellite cross-calibration. An Algorithm Theoretical Basis Document (ATBD) of the product is under evaluation by NASA. The CWC product inputs are 1) The MODIS Terra/Aqua surface reflectance product (MOD09A1/MYD09A1) 2) The MODIS land cover map product (MOD12Q1) reclassified to grassland, shrub-land and forest canopies; 3) An ANN trained with PROSPECT-SAILH; 4) A calibration file for each land cover type. The output is an ENVI file with the CWC values. The code is written in Matlab environment and is being adapted to read not only the 8 day MODIS composites, but also daily surface reflectance data. We plan to incorporate the cloud and snow mask and generate as output a geotiff file. Vegetation water content estimates will help predicting linkages between biogeochemical cycles, which will enable further understanding of feedbacks to atmospheric concentrations of greenhouse gases. It will also serve to estimate primary productivity of the biosphere; monitor/assess natural vegetation health related to drought, pollution or diseases

  15. Power Enhancement of Partial Shaded PV Array by Optimizing the Electrical Connection of Module

    Directory of Open Access Journals (Sweden)

    Wang Mengyao

    2015-01-01

    Full Text Available The maximum output power (Pmax generated from photovoltaic (PV array will be apparently reduced if the array is partially shaded. In order to enhance Pmax generated from partial shaded PV array, several interconnection schemes of array are proposed. Among these schemes, the totally cross tied (TCT scheme and the recently proposed static scheme are widely discussed. It was reported that Pmax produced with static scheme is equal to the TCT scheme even under worst conditions. However, in these simulations the illumination of every single module is assumed to be uniform, but in urban environments the illumination of modules on the edge of shadow is more likely to be non-uniform. In this paper, first, a comprehensive circuit-level simulation, which is implemented in PSpice, has been done to investigate performance of PV array with both TCT scheme and static scheme under different partial shading conditions. And the results show that Pmax generated from static scheme is higher than that form TCT scheme if the illumination of every single module is uniform, however if some modules are partially shaded, the Pmax with static scheme is more likely less than that with TCT scheme. Then, the electrical connection of a module is improved for the purpose of enhancing Pmax under partial shading conditions in which some modules in the array are partially shaded. And the simulation results show that Pmax is apparently increased by employing the improved modules.

  16. Seasonal contrasts in the response of coffee ants to agroforestry shade-tree management.

    Science.gov (United States)

    Teodoro, A V; Sousa-Souto, L; Klein, A-M; Tscharntke, T

    2010-12-01

    In many tropical landscapes, agroforestry systems are the last forested ecosystems, providing shade, having higher humidity, mitigating potential droughts, and possessing more species than any other crop system. Here, we tested the hypothesis that higher levels of shade and associated humidity in agroforestry enhance coffee ant richness more during the dry than rainy season, comparing ant richness in 22 plots of three coffee agroforestry types in coastal Ecuador: simple-shade agroforests (intensively managed with low tree species diversity), complex-shade agroforests (extensively managed with intermediate tree species diversity) and abandoned coffee agroforests (abandoned for 10-15 yr and resembling secondary forests). Seasonality affected responses of ant richness but not composition to agroforestry management, in that most species were observed in abandoned coffee agroforests in the dry season. In the rainy season, however, most species were found in simple-shade agroforests, and complex agroforestry being intermediate. Foraging coffee ants species composition did not change differently according to agroforestry type and season. Results show that shade appears to be most important in the dry seasons, while a mosaic of different land-use types may provide adequate environmental conditions to ant species, maximizing landscape-wide richness throughout the year. © 2010 Entomological Society of America

  17. SHADING AND SUBSTRATE ON THE PRODUCTION OF SEEDLINGS OF Erythrina velutina Willd.

    Directory of Open Access Journals (Sweden)

    Laércio Wanderley dos Santos

    2013-12-01

    Full Text Available http://dx.doi.org/10.5902/1980509812341Erythrina velutina Willd. (Fabaceae is used in traditional medicine in northeastern Brazil for its sudorificproperties, soothing, emollient, pectoral and local anesthetic. The aim of this study was to evaluate theeffect of substrate and shading on seedlings of Erythrina velutina. The experimental design was completelyrandomized in factorial scheme 5 x 2 (five substrates and two shades, with four replications and 10 plantsin each plot. The substrates were arisco, arisco + cattle manure 2:1 v/v, arisco + cattle manure 3:1 v/v, sand+ cattle manure 2:1 v/v, sand + cattle manure 3:1 v/v. The shadings were 0% shading (full sunlight and50% shading. The characteristics evaluated were stem diameter, height, leaf area, green and dry biomass ofroots and shoots, height/diameter and Dickson quality index.There was no significant difference in diameterbetween the different substrates. The environment in full sun favored the diameter and the root biomasswhereas the height was favored by shade. The substrates with cattle manure in its composition favorsthe development of plants of Erythrina velutina and higher seedling quality are produced in full sun andsubstrate arisco + cattle manure in the ratio 2:1

  18. Increased light-use efficiency sustains net primary productivity of shaded coffee plants in agroforestry system.

    Science.gov (United States)

    Charbonnier, Fabien; Roupsard, Olivier; le Maire, Guerric; Guillemot, Joannès; Casanoves, Fernando; Lacointe, André; Vaast, Philippe; Allinne, Clémentine; Audebert, Louise; Cambou, Aurélie; Clément-Vidal, Anne; Defrenet, Elsa; Duursma, Remko A; Jarri, Laura; Jourdan, Christophe; Khac, Emmanuelle; Leandro, Patricia; Medlyn, Belinda E; Saint-André, Laurent; Thaler, Philippe; Van Den Meersche, Karel; Barquero Aguilar, Alejandra; Lehner, Peter; Dreyer, Erwin

    2017-08-01

    In agroforestry systems, shade trees strongly affect the physiology of the undergrown crop. However, a major paradigm is that the reduction in absorbed photosynthetically active radiation is, to a certain extent, compensated by an increase in light-use efficiency, thereby reducing the difference in net primary productivity between shaded and non-shaded plants. Due to the large spatial heterogeneity in agroforestry systems and the lack of appropriate tools, the combined effects of such variables have seldom been analysed, even though they may help understand physiological processes underlying yield dynamics. In this study, we monitored net primary productivity, during two years, on scales ranging from individual coffee plants to the entire plot. Absorbed radiation was mapped with a 3D model (MAESPA). Light-use efficiency and net assimilation rate were derived for each coffee plant individually. We found that although irradiance was reduced by 60% below crowns of shade trees, coffee light-use efficiency increased by 50%, leaving net primary productivity fairly stable across all shade levels. Variability of aboveground net primary productivity of coffee plants was caused primarily by the age of the plants and by intraspecific competition among them (drivers usually overlooked in the agroforestry literature) rather than by the presence of shade trees. © 2017 John Wiley & Sons Ltd.

  19. A Pareto-based multi-objective optimization algorithm to design energy-efficient shading devices

    International Nuclear Information System (INIS)

    Khoroshiltseva, Marina; Slanzi, Debora; Poli, Irene

    2016-01-01

    Highlights: • We present a multi-objective optimization algorithm for shading design. • We combine Harmony search and Pareto-based procedures. • Thermal and daylighting performances of external shading were considered. • We applied the optimization process to a residential social housing in Madrid. - Abstract: In this paper we address the problem of designing new energy-efficient static daylight devices that will surround the external windows of a residential building in Madrid. Shading devices can in fact largely influence solar gains in a building and improve thermal and lighting comforts by selectively intercepting the solar radiation and by reducing the undesirable glare. A proper shading device can therefore significantly increase the thermal performance of a building by reducing its energy demand in different climate conditions. In order to identify the set of optimal shading devices that allow a low energy consumption of the dwelling while maintaining high levels of thermal and lighting comfort for the inhabitants we derive a multi-objective optimization methodology based on Harmony Search and Pareto front approaches. The results show that the multi-objective approach here proposed is an effective procedure in designing energy efficient shading devices when a large set of conflicting objectives characterizes the performance of the proposed solutions.

  20. The effect of partial shading on dye-sensitized solar cell module characteristics

    International Nuclear Information System (INIS)

    Pan, Bin; Weng, Jian; Chen, Shuanghong; Huang, Yang; Dai, Songyuan

    2014-01-01

    The dye-sensitized solar cell (DSC) is a kind of novel solar cell with prospects for building integrated photovoltaic applications. In some situations, a DSC module may work under partial shading conditions, and subsequently the module temperature and I–V characteristics change. In this work, the effect of partial shading on DSC module characteristics is experimentally studied and the temperature and electric output of the partially shaded DSC module are measured. The variations of module temperature and output performance are analyzed under short circuit conditions and a normal operating mode of charging battery. Furthermore, the stability of the partially shaded DSC module is also evaluated. It is found that the temperature rise of the DSC module caused by partial shading is slower and much smaller than the silicon solar cell, and the characteristics of the single DSC that suffered from short-term shading remain stable. For a DSC module operating in charging mode, the maximum power point and working point change when a shadow appears. (paper)

  1. The Atmospheric Chemistry and Canopy Exchange Simulation System (ACCESS: model description and application to a temperate deciduous forest canopy

    Directory of Open Access Journals (Sweden)

    R. D. Saylor

    2013-01-01

    Full Text Available Forest canopies are primary emission sources of biogenic volatile organic compounds (BVOCs and have the potential to significantly influence the formation and distribution of secondary organic aerosol (SOA mass. Biogenically-derived SOA formed as a result of emissions from the widespread forests across the globe may affect air quality in populated areas, degrade atmospheric visibility, and affect climate through direct and indirect forcings. In an effort to better understand the formation of SOA mass from forest emissions, a 1-D column model of the multiphase physical and chemical processes occurring within and just above a vegetative canopy is being developed. An initial, gas-phase-only version of this model, the Atmospheric Chemistry and Canopy Exchange Simulation System (ACCESS, includes processes accounting for the emission of BVOCs from the canopy, turbulent vertical transport within and above the canopy and throughout the height of the planetary boundary layer (PBL, near-explicit representation of chemical transformations, mixing with the background atmosphere and bi-directional exchange between the atmosphere and canopy and the atmosphere and forest floor. The model formulation of ACCESS is described in detail and results are presented for an initial application of the modeling system to Walker Branch Watershed, an isoprene-emission-dominated forest canopy in the southeastern United States which has been the focal point for previous chemical and micrometeorological studies. Model results of isoprene profiles and fluxes are found to be consistent with previous measurements made at the simulated site and with other measurements made in and above mixed deciduous forests in the southeastern United States. Sensitivity experiments are presented which explore how canopy concentrations and fluxes of gas-phase precursors of SOA are affected by background anthropogenic nitrogen oxides (NOx. Results from these experiments suggest that the

  2. THE PRE-PENUMBRAL MAGNETIC CANOPY IN THE SOLAR ATMOSPHERE

    Energy Technology Data Exchange (ETDEWEB)

    MacTaggart, David [School of Mathematics and Statistics University of Glasgow, Glasgow G12 8QW (United Kingdom); Guglielmino, Salvo L.; Zuccarello, Francesca [Dipartimento di Fisica e Astronomia—Sezione Astrofisica, Università di Catania, via S. Sofia 78, I-95123 Catania (Italy)

    2016-11-01

    Penumbrae are the manifestation of magnetoconvection in highly inclined (to the vertical direction) magnetic field. The penumbra of a sunspot tends to form, initially, along the arc of the umbra antipodal to the main region of flux emergence. The question of how highly inclined magnetic field can concentrate along the antipodal curves of umbrae, at least initially, remains to be answered. Previous observational studies have suggested the existence of some form of overlying magnetic canopy that acts as the progenitor for penumbrae. We propose that such overlying magnetic canopies are a consequence of how the magnetic field emerges into the atmosphere and are, therefore, part of the emerging region. We show, through simulations of twisted flux tube emergence, that canopies of highly inclined magnetic field form preferentially at the required locations above the photosphere.

  3. Effect of shading nets on the production and quality of blueberry fruit (Vaccinium corymbosum L. cv. Brigitta

    Directory of Open Access Journals (Sweden)

    Mario Marcelo Rodríguez Beraud

    2015-03-01

    Full Text Available Growth, development and fruit quality blueberry (Vaccinium corymbosum L. variety Brigitta under different shade nets were evaluated. Assays were performed in plants 7 years in a commercial orchard Collipulli, Araucanía Region, Chile. Treatments were a control without shading and four types of screens: a red 40% and 18% shade; aluminized mesh with 40% shade and a black mesh 35% shade. In fruits shade of red mesh 40% greater equatorial and polar diameter were observed and three weeks later harvested the fruits of treatment without mesh. In growing shade 40% aluminized mesh phenological stages extension lag and the maximum weekly production two weeks over control was observed. The highest yields were observed in plants of treatment and control shade of red mesh 40%, with 11008 kg ha-1 and 10461 kg ha-1, respectively, while the lowest was in red mesh 18% with 9668 kg ha-1. The fruits grown under shade of red mesh 18% showed the highest number of fruits per plant with 1806 berries per plant, fruit weight less than 1.69 g with the strongest with 3.76 N mm-1 module deformability. Therefore, the largest weight berry fruits observed in non-mesh screen and 40% red shading, together with the increased size and performance.

  4. Competition and facilitation structure plant communities under nurse tree canopies in extremely stressful environments.

    Science.gov (United States)

    Al-Namazi, Ali A; El-Bana, Magdy I; Bonser, Stephen P

    2017-04-01

    Nurse plant facilitation in stressful environments can produce an environment with relatively low stress under its canopy. These nurse plants may produce the conditions promoting intense competition between coexisting species under the canopy, and canopies may establish stress gradients, where stress increases toward the edge of the canopy. Competition and facilitation on these stress gradients may control species distributions in the communities under canopies. We tested the following predictions: (1) interactions between understory species shift from competition to facilitation in habitats experiencing increasing stress from the center to the edge of canopy of a nurse plant, and (2) species distributions in understory communities are controlled by competitive interactions at the center of canopy, and facilitation at the edge of the canopy. We tested these predictions using a neighbor removal experiment under nurse trees growing in arid environments. Established individuals of each of four of the most common herbaceous species in the understory were used in the experiment. Two species were more frequent in the center of the canopy, and two species were more frequent at the edge of the canopy. Established individuals of each species were subjected to neighbor removal or control treatments in both canopy center and edge habitats. We found a shift from competitive to facilitative interactions from the center to the edge of the canopy. The shift in the effect of neighbors on the target species can help to explain species distributions in these canopies. Canopy-dominant species only perform well in the presence of neighbors in the edge microhabitat. Competition from canopy-dominant species can also limit the performance of edge-dominant species in the canopy microhabitat. The shift from competition to facilitation under nurse plant canopies can structure the understory communities in extremely stressful environments.

  5. Quantifying interception associated with new urban vegetation canopies

    Science.gov (United States)

    Yerk, W.; Montalto, F. A.

    2013-12-01

    Interception of precipitation by vegetation canopies has long been recognized as an important component of the hydrologic cycle, though most research has been in closed or sparse canopy forests. Much less work has been published on interception by urban vegetation, and especially associated with the low growing shrubs commonly installed in green infrastructure program. To inform urban watershed model with vegetation-specific interception data, a field experiment was designed to directly measure canopy throughfall associated with two shrub species commonly included in urban greening programs. Data was collected at a high (e.g. five second) sampling frequency. A non-parametric Kruskal-Wallis test performed on data collected between August and October of 2012 demonstrated statistically significant (p= 0.0011) differences in recorded throughfall between two species (94% for Itea virginica, 86% for Cornus sericea). Additionally, the results suggested that the relationship of throughfall to rainfall intensity varied by species. For Itea, the ratio of throughfall to precipitation intensity was close to 1:1. However, for Cornus, the throughfall rate was on average slower (or 0.85 of the precipitation intensity). An improved and expanded set-up installed in 2013 added two additional species (Prunus laurocerasus and Hydrangea quercifolia). The 2013 results confirm interspecies differences in both throughfall amount, and in the relationship of throughfall rate to precipitation intensity. The results are discussed with respect to droplet splashing and enhanced evaporation within the canopy. Both years' findings suggest that the quantity of water intercepted by vegetation canopies exceeds the canopy storage capacity, as assumed in many conventional hydrologic models.

  6. Effect of canopy architectural variation on transpiration and thermoregulation

    Science.gov (United States)

    Linn, R.; Banerjee, T.

    2017-12-01

    One of the major scientific questions identified by the NGEE - Tropics campaign is the effect of disturbances such as forest fires, vegetation thinning and land use change on carbon, water and energy fluxes. Answers to such questions can help develop effective forest management strategies and shape policies to mitigate damages under natural and anthropogenic climate change. The absence of horizontal and vertical variation of forest canopy structure in current models is a major source of uncertainty in answering these questions. The current work addresses this issue through a bottom up process based modeling approach to systematically investigate the effect of forest canopy architectural variation on plant physiological response as well as canopy level fluxes. A plant biophysics formulation is used which is based on the following principles: (1) a model for the biochemical demand for CO2 as prescribed by photosynthesis models. This model can differentiate between photosynthesis under light-limited and nutrient-limited scenarios. (2) A Fickian mass transfer model including transfer through the laminar boundary layer on leaves that may be subjected to forced or free convection depending upon the mean velocity and the radiation load; (3) an optimal leaf water use strategy that maximizes net carbon gain for a given transpiration rate to describe the stomatal aperture variation; (4) a leaf-level energy balance to accommodate evaporative cooling. Such leaf level processes are coupled to solutions of atmospheric flow through vegetation canopies. In the first test case, different scenarios of top heavy and bottom heavy (vertical) foliage distributions are investigated within a one-dimensional framework where no horizontal heterogeneity of canopy structure is considered. In another test case, different spatial distributions (both horizontal and vertical) of canopy geometry (land use) are considered, where flow solutions using large eddy simulations (LES) are coupled to the

  7. The relationship between reference canopy conductance and simplified hydraulic architecture

    Science.gov (United States)

    Novick, Kimberly; Oren, Ram; Stoy, Paul; Juang, Jehn-Yih; Siqueira, Mario; Katul, Gabriel

    2009-06-01

    Terrestrial ecosystems are dominated by vascular plants that form a mosaic of hydraulic conduits to water movement from the soil to the atmosphere. Together with canopy leaf area, canopy stomatal conductance regulates plant water use and thereby photosynthesis and growth. Although stomatal conductance is coordinated with plant hydraulic conductance, governing relationships across species has not yet been formulated at a practical level that can be employed in large-scale models. Here, combinations of published conductance measurements obtained with several methodologies across boreal to tropical climates were used to explore relationships between canopy conductance rates and hydraulic constraints. A parsimonious hydraulic model requiring sapwood-to-leaf area ratio and canopy height generated acceptable agreement with measurements across a range of biomes (r2=0.75). The results suggest that, at long time scales, the functional convergence among ecosystems in the relationship between water-use and hydraulic architecture eclipses inter-specific variation in physiology and anatomy of the transport system. Prognostic applicability of this model requires independent knowledge of sapwood-to-leaf area. In this study, we did not find a strong relationship between sapwood-to-leaf area and physical or climatic variables that are readily determinable at coarse scales, though the results suggest that climate may have a mediating influence on the relationship between sapwood-to-leaf area and height. Within temperate forests, canopy height alone explained a large amount of the variance in reference canopy conductance (r2=0.68) and this relationship may be more immediately applicable in the terrestrial ecosystem models.

  8. Solar Shading in Low Energy Office Buildings - Design Strategy and User Perception

    Directory of Open Access Journals (Sweden)

    Steinar Grynning

    2017-06-01

    Full Text Available The objective of this paper is to investigate the visual comfort and quality of daylight in modern office buildings in the Nordic climate. A study of various daylight-related aspects and qualities was carried out for three different office buildings, using a combination of quantitative and qualitative methods. The focus was on a combination of user perception of daylight quality and assessment of the daylight amount and quality, by using the daylight factor (DF and useful daylight illuminance parameters. Previous studies and experiences from construction examples indicate that users, in general, complain about lack of manual control of systems and too low daylight levels, even if the requirements in the building codes are satisfied. Furthermore, they complain about control algorithms of the shading devices, which cause undesired automatic opening and closure of such devices. Thus, causing disturbances and irritation amongst the users. Hence, interviews with key personnel in a modern and architecturally acclaimed office building were carried out in addition to an in-depth analysis of previous surveys of a zero-energy office building. It was found that automatic moveable shading can be regarded as a source of discomfort. This is due to the lack of manual-control override possibilities, which causes disturbances due to the system moving up and down. In one of the offices, the users disabled the exterior shading system. However, the external fixed shading and the internal manually operated roller blinds were found to be satisfactory. The results from a previous study showed that the users in the Marche building are in general satisfied with the daylight. One of the main reasons for this, according to the users, is that they have manual control of the shading system. Manual control of the shading systems is preferred by users in the office buildings studied. Daylight simulations showed that the external fixed shading system combined with internal

  9. Fast shading correction for cone beam CT in radiation therapy via sparse sampling on planning CT.

    Science.gov (United States)

    Shi, Linxi; Tsui, Tiffany; Wei, Jikun; Zhu, Lei

    2017-05-01

    The image quality of cone beam computed tomography (CBCT) is limited by severe shading artifacts, hindering its quantitative applications in radiation therapy. In this work, we propose an image-domain shading correction method using planning CT (pCT) as prior information which is highly adaptive to clinical environment. We propose to perform shading correction via sparse sampling on pCT. The method starts with a coarse mapping between the first-pass CBCT images obtained from the Varian TrueBeam system and the pCT. The scatter correction method embedded in the Varian commercial software removes some image errors but the CBCT images still contain severe shading artifacts. The difference images between the mapped pCT and the CBCT are considered as shading errors, but only sparse shading samples are selected for correction using empirical constraints to avoid carrying over false information from pCT. A Fourier-Transform-based technique, referred to as local filtration, is proposed to efficiently process the sparse data for effective shading correction. The performance of the proposed method is evaluated on one anthropomorphic pelvis phantom and 17 patients, who were scheduled for radiation therapy. (The codes of the proposed method and sample data can be downloaded from https://sites.google.com/view/linxicbct) RESULTS: The proposed shading correction substantially improves the CBCT image quality on both the phantom and the patients to a level close to that of the pCT images. On the phantom, the spatial nonuniformity (SNU) difference between CBCT and pCT is reduced from 74 to 1 HU. The root of mean square difference of SNU between CBCT and pCT is reduced from 83 to 10 HU on the pelvis patients, and from 101 to 12 HU on the thorax patients. The robustness of the proposed shading correction is fully investigated with simulated registration errors between CBCT and pCT on the phantom and mis-registration on patients. The sparse sampling scheme of our method successfully

  10. PowerShades II. Optimisation and validation of highly transparent photovoltaic. Final report

    Energy Technology Data Exchange (ETDEWEB)

    2010-07-15

    The objective of the project is continued development and validation of a novel Danish photovoltaic product with the work title ''PowerShade''. The PowerShade insulating glazing unit (IGU) is a combination of a strong solar shading device and a power producing photovoltaic coating. The core technology in the PowerShade IGU is a thin film silicon photovoltaic generator applied to a micro structured substrate. The geometry of the substrate provides the unique combination of properties that characterizes the PowerShade module - strong progressive shading, high transparency, and higher electrical output than other semitransparent photovoltaic products with similar transparencies. The project activities fall in two categories, namely development of the processing/product and validation of the product properties. The development part of the project is focussed on increasing the efficiency of the photovoltaic generator by changing from a single-stack type cell to a tandem-stack type cell. The inclusion of PowerShade cells in insulating glazing (IG) units is also addressed in this project. The validation part of the project aims at validation of stability, thermal and optical properties as well as validation of the electrical yield of the product. The validation of thermal and optical properties has been done using full size modules installed in a test facility built during the 2006-08 ''PowerShades'' project. The achieved results will be vital in the coming realisation of a commercial product. Initial processing steps have been automated, and more efficient tandem-type solar cells have been developed. A damp heat test of an IGU has been carried out without any degradation of the solar cell. The PowerShade module assembly concept has been further developed and discussed with different automation equipment vendors and a pick-and-place tool developed. PowerShade's influence on the indoor climate has been modelled and verified by

  11. Climate-change refugia: shading reef corals by turbidity.

    Science.gov (United States)

    Cacciapaglia, Chris; van Woesik, Robert

    2016-03-01

    Coral reefs have recently experienced an unprecedented decline as the world's oceans continue to warm. Yet global climate models reveal a heterogeneously warming ocean, which has initiated a search for refuges, where corals may survive in the near future. We hypothesized that some turbid nearshore environments may act as climate-change refuges, shading corals from the harmful interaction between high sea-surface temperatures and high irradiance. We took a hierarchical Bayesian approach to determine the expected distribution of 12 coral species in the Indian and Pacific Oceans, between the latitudes 37°N and 37°S, under representative concentration pathway 8.5 (W m(-2) ) by 2100. The turbid nearshore refuges identified in this study were located between latitudes 20-30°N and 15-25°S, where there was a strong coupling between turbidity and tidal fluctuations. Our model predicts that turbidity will mitigate high temperature bleaching for 9% of shallow reef habitat (to 30 m depth) - habitat that was previously considered inhospitable under ocean warming. Our model also predicted that turbidity will protect some coral species more than others from climate-change-associated thermal stress. We also identified locations where consistently high turbidity will likely reduce irradiance to turbid nearshore refuges identified in this study, particularly in the northwestern Hawaiian Islands, the northern Philippines, the Ryukyu Islands (Japan), eastern Vietnam, western and eastern Australia, New Caledonia, the northern Red Sea, and the Arabian Gulf, should become part of a judicious global strategy for reef-coral persistence under climate change. © 2015 John Wiley & Sons Ltd.

  12. Shades of irony in the anti-language of Amos

    Directory of Open Access Journals (Sweden)

    William Domeris

    2016-08-01

    Full Text Available The rhetoric of Amos includes a wonderful mixture of humour and threat, sarcasm and irony, hyperbole and prediction. Holding the fabric of this conversation together is Amos’s place within the prophetic minority – the Yahweh-only party (his anti-society. Making use of sociolinguistics, and particularly the idea of anti-language, I take a closer look at Amos, including his use of overlexicalisation, insider-humour and all the shades of irony one might expect. Typically of a member of an anti-society, Amos exaggerates the differences between insider and outsider, in this case, speaking of ‘ivory houses’, ‘the cattle of Bashan’ while appealing to his successful attempts to save the rich from the wrath of God. The offenses of the outsiders are sometimes crystal clear and at other times shrouded in metaphor, and so too is the fate of these people. In reading Amos, we are constantly in danger of falling victim to the persuasive power of his rhetoric. We are drawn into the world of Amos, quickly accepting his boundaries and the ideology of his anti-society, his depiction of reality and his stark caricature of the rich. The rhetoric is persuasive and the irony is divisive forcing a choice of black and white, believer and unbeliever, rich and poor, oppressors and oppressed. We struggle to swim against the current and instead long to respond to Amos’s invitation to live (Am 5:5 – perhaps even to discover that elusive hope at which the book hints: Most of history has been the forging of structures of security and appropriate loyalty symbols, to announce and defend one’s personal identity, one’s group, and one’s gender issues and identity. (Rohr 2011:4

  13. Correlation between grain orientation and the shade of color etching

    International Nuclear Information System (INIS)

    Szabo, Peter J.; Kardos, I.

    2010-01-01

    Color etching is an extremely effective metallographic technique not only for making grains well visible, but also for making them distinguishable for automated image analyzers. During color etching, a thin film is formed on the surface of the specimen. The thickness of this layer is in the order of magnitude of the visible light and since both the metal-film boundary and the film surface reflect light, an interference occurs. A wavelength-component of the white line is eliminated and its complementary color will be seen on the surface. As the thickness changes, the colors also change grain by grain. The thickness of the film is dependent on several factors, mostly on the type of the phase. However, different color shades can be observed on the surfaces of single phase materials, which phenomenon is caused by the different crystallographic orientations of the grains. This paper shows a combined color etching electron backscatter diffraction (EBSD) investigation of cast iron. An area of the surface of a gray cast iron specimen was etched. Colors were characterized by their luminescence and their red, green and blue intensity. An EBSD orientation map was taken from the same area and the orientations of the individual grains were determined. Results showed that a strong correlation was found between the luminescence and the R, G, B intensity of the color and the angle between the specimen normal and the direction, while such correlation was not observed between the color parameters and the and directions, respectively. This indicates that film thickness is sensitive to the direction of the crystal.

  14. Utilising shade to optimize UV exposure for vitamin D

    Science.gov (United States)

    Turnbull, D. J.; Parisi, A. V.

    2008-06-01

    Numerous studies have stated that humans need to utilise full sun radiation, at certain times of the day, to assist the body in synthesising the required levels of vitamin D3. The time needed to be spent in the full sun depends on a number of factors, for example, age, skin type, latitude, solar zenith angle. Current Australian guidelines suggest exposure to approximately 1/6 to 1/3 of a minimum erythemal dose (MED), depending on age, would be appropriate to provide adequate vitamin D3 levels. The aim of the study was to determine the exposure times to diffuse solar UV to receive exposures of 1/6 and 1/3 MED for a changing solar zenith angle in order to assess the possible role that diffuse UV (scattered radiation) may play in vitamin D3 effective UV exposures (UVD3). Diffuse and global erythemal UV measurements were conducted at five minute intervals over a twelve month period for a solar zenith angle range of 4° to 80° at a latitude of 27.6° S. For a diffuse UV exposure of 1/3 MED, solar zenith angles smaller than approximately 50° can be utilised for exposure times of less than 10 min. Spectral measurements showed that, for a solar zenith angle of 40°, the UVA (315-400 nm) in the diffuse component of the solar UV is reduced by approximately 62% compared to the UVA in the global UV, whereas UVD3 wavelengths are only reduced by approximately 43%. At certain latitudes, diffuse UV under shade may play an important role in providing the human body with adequate levels of UVD3 (290-315 nm) radiation without experiencing the high levels of UVA observed in full sun.

  15. Shaded Relief with Height as Color, North America

    Science.gov (United States)

    2003-01-01

    Manitoba to North Dakota and Minnesota, huge striations clearly show the flow pattern of the glaciers. And southwest of Lakes Michigan, Huron, and Erie, arcing ridges of sediment, called terminal moraines, show where glaciers dumped sediment at their melting ends.In eastern Canada, New York, and New England, the terrain has been scoured by glaciers, and eroded by streams, particularly along fractures in the bedrock. In Labrador and Quebec, the Mistastin, Manicougan, and Clearwater Lakes meteor impact craters can also be seen. Further south, narrow curving ridges of upturned and eroded layered rocks form most of the Appalachian Mountains. In contrast, around the Caribbean Sea region (Yucatan, Florida, and the Bahamas), flat-lying, stable limestone platforms are common, while the most eastern islands of the Caribbean include active volcanoes along another convergence zone of tectonic plates.Two visualization methods were combined to produce the image: shading and color coding of topographic height. The shade image was derived by computing topographic slope in the northwest-southeast direction, so that northwest slopes appear bright and southeast slopes appear dark. Color coding is directly related to topographic height, with green at the lower elevations, rising through yellow and tan, to white at the highest elevations.Elevation data used in this image were acquired by the Shuttle Radar Topography Mission aboard the Space Shuttle Endeavour, launched on Feb. 11, 2000. SRTM used the same radar instrument that comprised the Spaceborne Imaging Radar-C/X-Band Synthetic Aperture Radar (SIR-C/X-SAR) that flew twice on the Space Shuttle Endeavour in 1994. SRTM was designed to collect 3-D measurements of the Earth's surface. To collect the 3-D data, engineers added a 60-meter (approximately 200-foot) mast, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping

  16. The third RAdiation transfer Model Intercomparison (RAMI) exercise: Documenting progress in canopy reflectance models

    NARCIS (Netherlands)

    Widlowski, J.L.; Taberner, M.; Pinty, B.; Bruniquel-Pinel, V.; Disney, M.I.; Fernandes, R.; Gastellu-Etchegorry, J.P.; Gobron, N.; Kuusk, A.; Lavergne, T.; LeBlanc, S.; Lewis, P.E.; Martin, E.; Mõttus, M.; North, P.R.J.; Qin, W.; Robustelli, M.; Rochdi, N.; Ruiloba, R.; Thompson, R.; Verhoef, W.; Verstraete, M.M.; Xie, D.

    2007-01-01

    [1] The Radiation Transfer Model Intercomparison ( RAMI) initiative benchmarks canopy reflectance models under well-controlled experimental conditions. Launched for the first time in 1999, this triennial community exercise encourages the systematic evaluation of canopy reflectance models on a

  17. Third Radiation Transfer Model Intercomparison (RAMI) exercise : Documenting progress in canopy reflectance models

    NARCIS (Netherlands)

    Widlowski, J.-L.; Taberner, M.; Pinty, B.; Bruniquel-Pinel, V.; Disney, M.; Fernandes, R.; Gastellu-Etchegorry, J.P.; Gobron, N.; Kuusk, A.; Lavergne, T.; Leblanc, S.; Lewis, P.E.; Martin, E.; Mottus, M.; North, P.R.J.; Qin, W.; Robustelli, M.; Rochdi, N.; Ruiloba, R.; Soler, C.; Thompson, R.; Verhoef, W.; Xie, D.; Thompson, R.

    2007-01-01

    The Radiation Transfer Model Intercomparison (RAMI) initiative benchmarks canopy reflectance models under well‐controlled experimental conditions. Launched for the first time in 1999, this triennial community exercise encourages the systematic evaluation of canopy reflectance models on a voluntary

  18. LBA-ECO LC-15 Aerodynamic Roughness Maps of Vegetation Canopies, Amazon Basin: 2000

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set, LBA-ECO LC-15 Aerodynamic Roughness Maps of Vegetation Canopies, Amazon Basin: 2000, provides physical roughness maps of vegetation canopies in the...

  19. Exploring Relationships between Canopy Architecture, Light Distribution, and Photosynthesis in Contrasting Rice Genotypes Using 3D Canopy Reconstruction

    Directory of Open Access Journals (Sweden)

    Alexandra J. Burgess

    2017-05-01

    Full Text Available The arrangement of leaf material is critical in determining the light environment, and subsequently the photosynthetic productivity of complex crop canopies. However, links between specific canopy architectural traits and photosynthetic productivity across a wide genetic background are poorly understood for field grown crops. The architecture of five genetically diverse rice varieties—four parental founders of a multi-parent advanced generation intercross (MAGIC population plus a high yielding Philippine variety (IR64—was captured at two different growth stages using a method for digital plant reconstruction based on stereocameras. Ray tracing was employed to explore the effects of canopy architecture on the resulting light environment in high-resolution, whilst gas exchange measurements were combined with an empirical model of photosynthesis to calculate an estimated carbon gain and total light interception. To further test the impact of different dynamic light patterns on photosynthetic properties, an empirical model of photosynthetic acclimation was employed to predict the optimal light-saturated photosynthesis rate (Pmax throughout canopy depth, hypothesizing that light is the sole determinant of productivity in these conditions. First, we show that a plant type with steeper leaf angles allows more efficient penetration of light into lower canopy layers and this, in turn, leads to a greater photosynthetic potential. Second the predicted optimal Pmax responds in a manner that is consistent with fractional interception and leaf area index across this germplasm. However, measured Pmax, especially in lower layers, was consistently higher than the optimal Pmax indicating factors other than light determine photosynthesis profiles. Lastly, varieties with more upright architecture exhibit higher maximum quantum yield of photosynthesis indicating a canopy-level impact on photosynthetic efficiency.

  20. The dynamics of aerosol behaviour and fate within spruce canopies

    International Nuclear Information System (INIS)

    Ould-Dada, Zitouni

    1996-01-01

    The current work was intended to provide data on aerosol inputs to forest ecosystems and their subsequent fate. The background to the project was the Chernobyl accident which highlighted the importance of forests and other semi-natural ecosystems as a link in the transfer of radioactivity to man. In the aftermath of the Chernobyl accident, forests were identified as a specific type of semi-natural ecosystem for which radioecological data were almost completely absent within the countries of the European Union. Information on radionuclide behaviour and transfer in forest ecosystems was therefore needed to establish and test radiological assessment models which can be used to evaluate the likely contribution to radiological dose-to-man contaminated forests may make. The objective of this study was thus to provide data on dry deposition, resuspension and field loss of aerosols to forest canopies, in particular those of Norway spruce (Picea abies), from wind tunnel experiments conducted with small scale 'model' canopies. An aerosol generation system was developed to produce aerosol particles in the size range of 0.13-1.37 μm (VMD). Particle size distributions can be controlled within desired limits and with sufficient stability over time allowing the technique to be suitable for use in extended aerosol deposition studies. A full scale dry deposition experiment using 0.82 μm (VMAD) uranium particles was performed in the wind tunnel using Norway spruce saplings of approximately 45 cm height. Deposition velocities (V g ) were obtained and these were related to meteorological measurements (wind speed, friction velocity, turbulence intensity) inside the wind tunnel and LAI of the canopy. The latter was divided into five horizontal layers and both horizontal and vertical variations in deposition were assessed. A V g value of 0.497 cm s -1 was obtained for the