Science.gov

Sample records for shades fields

  1. Generalized shading analysis for paraboloidal collector fields

    NASA Technical Reports Server (NTRS)

    Osborn, D. B.

    1980-01-01

    This paper presents the development and results of a generalized shading analysis for a field of point-focus parabolic dish concentrators. Shading of one concentrator by another with attendant loss of energy is a function of the position of the sun and the relative locations of the concentrators within the field. A method is presented for determining the annualized energy loss which includes a trade-off of system life-cycle energy as a function of concentrator spacing and field geometric layout. System energy output is computed on an annualized basis, employing 15 minute-increment environmental data tapes for the year 1976 at Barstow, California. For a land cost of $5000 per acre, lowest system energy cost occurs at about a 25 percent packing fraction (concentrator area/land area) for a typical 1-MWe dish-Stirling solar thermal power plant. Basic equations are given for computing the shading and concomitant energy loss as a function of concentrator center-to-center spacing, field layout site location.

  2. Sun and Shade Leaves: Some Field Investigations.

    ERIC Educational Resources Information Center

    Tomley, David

    1983-01-01

    Several simple experiments illustrating how the light regime affects the final form of dog's mercury (Mercurialis perennis) are provided. These experiments, which can also be done with other plants, focus on differences in the anatomy, morphology, and physiology of sun and shade leaves. (JN)

  3. Effects of shading on early growth of Cyclobalanopsis glauca (Fagaceae) in subtropical abandoned fields: Implications for vegetation restoration

    NASA Astrophysics Data System (ADS)

    Du, Xiaojun; Liu, Canran; Yu, Xingjun; Ma, Keping

    2008-03-01

    In order to restore natural ecosystems and improve the environment, the restoration of abandoned agricultural lands to their native vegetation is urgent and challenging work. In response to a new initiative in China, the National Engineering Program on Converting Abandoned Agriculture Land to Forest Stands, this study was undertaken to seek novel approaches for accelerating forest restoration efforts. We tested the hypothesis that the late-successional tree species, Cyclobalanopsis glauca, is not able to establish and grow in full-sun environments on abandoned lands due to inhibited early growth of C. glauca seedlings. We carried out a 2-year field experiment on early growth of C. glauca in subtropical abandoned fields under three different shade treatments (no shade, fully exposed to ambient sunlight; medium shade and heavy shade, about 40% and 22% of full ambient sunlight, respectively) and compared their growth and biomass to 2-year old C. glauca seedlings growing in a natural forest environment. Our results showed that: 1) both medium shade and heavy shade treatments enhanced the establishment and early growth of C. glauca seedlings as compared to no shade, and that growth and survivorship was greatest in the heavy shade treatment; and 2) the growth and biomass of C. glauca seedlings on abandoned fields (in the cleared and prepared plots in this study) were equal to or greater than the growth and biomass of seedlings growing in nearby forests. This study supports the viewpoint that consideration of species shade tolerance is important when developing restoration management strategies.

  4. Effects of mutual shading on the regulation of photosynthesis in field-grown sorghum.

    PubMed

    Li, Tao; Liu, Li-Na; Jiang, Chuang-Dao; Liu, Yu-Jun; Shi, Lei

    2014-08-01

    In the field, close planting inevitably causes mutual shading and depression of leaf photosynthesis. To clarify the regulative mechanisms of photosynthesis under these conditions, the effects of planting density on leaf structure, gas exchange and proteomics were carefully studied in field-grown sorghum. In the absence of mineral deficiency, (1) close planting induced a significant decrease in light intensity within populations, which further resulted in much lower stomatal density and other anatomical characteristics associated with shaded leaves; (2) sorghum grown at high planting density had a lower net photosynthetic rate and stomatal conductance than those grown at low planting density; (3) approximately 62 protein spots changed their expression levels under the high planting density conditions, and 22 proteins associated with photosynthesis were identified by mass spectrometry. Further analysis revealed the depression of photosynthesis caused by mutual shading involves the regulation of leaf structure, absorption and transportation of CO2, photosynthetic electron transport, production of assimilatory power, and levels of enzymes related to the Calvin cycle. Additionally, heat shock protein and oxygen-evolving enhancer protein play important roles in photoprotection in field-grown sorghum. A model for the regulation of photosynthesis under mutual shading was suggested based on our results.

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

    NASA Astrophysics Data System (ADS)

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

    2016-05-01

    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.

  6. Effects of shading on spike differentiation and grain yield formation of summer maize in the field

    NASA Astrophysics Data System (ADS)

    Cui, Haiyan; Camberato, James J.; Jin, Libin; Zhang, Jiwang

    2015-09-01

    A field experiment was conducted to study the effects of shading on tassel and ear development and yield formation of three summer maize hybrids Zhenjie 2 (ZJ2), Denghai 605 (DH605), and Zhengdan 958 (ZD958). The ambient sunlight treatment was used as control (CK) and shading treatments (40 % of ambient sunlight) were applied at different growth stages from silking stage (R1) to physiological maturity stage (R6) (treatment S1), from the sixth extended leaf stage (V6) to R1 (treatment S2) and from seeding to R6 (treatment S3). Shading had no significant effect on the time from seeding to shoot emergence (VE); however, subsequent growth and development were delayed with shading beyond this point. The differentiation time of both tassel and ear delayed, and female spike (tassel) floret differentiation, sexual organ formation time, and anthesis-silking interval (ASI) were lengthened. After shading, the total number of floret, silk, and fertilization floret reduced significantly; the number of abortive seeds increased, and the total setting percentage among different treatments showed that CK>S2>S1>S3; and the total setting percentages in S1, S2, and S3 of ZD958 were 44, 72, and 15 % respectively. The total floret number of tassel primordium differentiation, fertility rate, and seed setting rate of florets in S3 treatment was the minimum; kernels per ear decreased seriously and single ear setting percentage was only 16 %; although floret degeneration number of S2 during ear differentiation stages increased and floret fertility rate reduced than that of CK, fertilization flower seed production increased and abortive seed decreased after canceling shading. Aborted kernel of S1 increased and kernel dry weight reduced, resulting in a significant decrease of kernel number per ear and kernel weight, and the grain abortive rate of 40-62 %. In conclusion, shading changed the growth and development process and caused infertility of tassel and ear; tassel branches decreased

  7. Influence of the Exposure Time after Removing of Covering Materials over Shading Tea Field on the Quality of Gyokuro

    NASA Astrophysics Data System (ADS)

    Sakaida, Teruki; Yoshioka, Tetsuya; Nitabaru, Juichi; Nakazono, Kentaro; Kubota, Akira; Nariyama, Hideki

    We revealed the influences of the exposure time after removing of covering materials over shading tea field for making gyokuro on the quality of made tea. As the exposure time increased, the green color of the fresh leaves faded; their total amino acid and theanine contents reduced; and the concentration of dimethyl sulfide, a representative aromatic compound in gyokuro, decreased. In contrast, the catechin content increased. The overall quality of the tea was lowered. These results indicated it was necessary to plucking of tea shoots for short time after removing of covering materials over shading tea field.

  8. Shade Avoidance

    PubMed Central

    Casal, Jorge J.

    2012-01-01

    The presence of neighboring vegetation modifies the light environment experienced by plants, generating signals that are perceived by phytochromes and cryptochromes. These signals cause large changes in plant body form and function, including enhanced growth of the hypocotyl and petioles, a more erect position of the leaves and early flowering in Arabidopsis thaliana. Collectively, these so-called shade-avoidance responses tend to reduce the degree of current or future shade by neighbors. Shade light signals increase the abundance of PHYTOCHROME INTERACTING FACTOR 4 (PIF4) and PIF5 proteins, promote the synthesis and redirection of auxin, favor the degradation of DELLA proteins and increase the expression of auxin, gibberellins and brassinosteroid-promoted genes, among other events downstream the photoreceptors. Selectively disrupting these events by genetic or pharmacological approaches affects shade-avoidance responses with an intensity that depends on the developmental context and the environment. Shade-avoidance responses provide a model to investigate the signaling networks used by plants to take advantage of the cues provided by the environment to adjust to the challenges imposed by the environment itself. PMID:22582029

  9. Influence of sun and shade conditions on Gratiana boliviana (Coleoptera: Chrysomelidae) abundance and feeding activity on tropical soda apple (Solanales: Solanaceae) under field conditions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tropical soda apple (Solanum viarum Dunal) is a perennial invasive weed species which has become a serious problem in both agricultural and natural areas of the southeastern United States. A field survey was conducted at a ranch in Madison County, Florida, to assess the effect of sun and shade condi...

  10. Winter wheat and summer shade

    NASA Astrophysics Data System (ADS)

    Artru, S.; Garre, S.; Lassois, L.; Dupraz, C.

    2014-12-01

    Agroforestry research is in full expansion, but uncertainty remains on the performance of combinations of species with regard to the broad range of possible species associations. In addition, the variability of environmental conditions under which agroforestry stands can be successfully developed is unknown. Under Belgian pedoclimatic conditions, tree-crop competition for light might be the principal limiting factor in the agroforestry context. Most studies show that shade stress induces a systematic reduction of final crop yield. However, the response of a specific crop to shade is highly dependent on environmental conditions. In agroforestry systems, the tree canopy reduces the incident radiation for the crop following a dynamic spatio-temporal pattern. In this study, we will report on the efficiency of wheat under artificial dynamic shade in the experimental farm of Gembloux Agro-Bio Tech, Belgium in order to evaluate it's potential for agroforestry purposes in the same region. Wheat productivity and development under artificial shade conditions have been monitored during 1 year and the observations will be continued for 2 more years. We constructed an artificial shade structure, which mimics the light environment observed under hybrid walnut agroforestry trees: periodic fluctuation in radiation transmittance and discontinuous light quantity. We collected information on biomass development, soil state and radiation patterns in the field. Using this data, we evaluated the influence of dynamic shade, light availability and the efficiency with which energy is converted in wheat dry matter under the artificial shade treatment. This, in combination with modeling, will allow a thorough study of the potential of wheat-walnut agroforestry systems in the Hesbaye region in Belgium.

  11. Retractable Sun Shade

    NASA Technical Reports Server (NTRS)

    Frank, A.; Derespinis, S. F.; Mockovciak, John, Jr.

    1986-01-01

    Window-shade type spring roller contains blanket, taken up by rotating cylindrical frame and held by frame over area to be shaded. Blanket made of tough, opaque polyimide material. Readily unfurled by mechanism to protect space it encloses from Sun. Blanket forms arched canopy over space and allows full access to it from below. When shading not needed, retracted mechanism stores blanket compactly. Developed for protecting sensitive Space Shuttle payloads from direct sunlight while cargo-bay doors open. Adapted to shading of greenhouses, swimming pools, and boats.

  12. Dynamic Light and Shade.

    ERIC Educational Resources Information Center

    Hogarth, Burne

    This student artist's handbook provides illustrations and instructions for rendering three-dimensional form with light and shade. Focus is on realistic representation and imitation of natural phenomena. Fifteen chapters cover: (1) "Black-and-White Silhouette; (2) "Minimal Light"; (3) "Five Categories of Light and Shade"; (4) "Single-Source Light";…

  13. VizieR Online Data Catalog: AzTEC survey of the SHADES fields. II. (Michalowski+, 2012)

    NASA Astrophysics Data System (ADS)

    Michalowski, M. J.; Dunlop, J. S.; Ivison, R. J.; Cirasuolo, M.; Caputi, K. I.; Aretxaga, I.; Arumugam, V.; Austermann, J. E.; Chapin, E. L.; Chapman, S. C.; Coppin, K. E. K.; Egami, E.; Hughes, D. H.; Ibar, E.; Mortier, A. M. J.; Schael, A. M.; Scott, K. S.; Smail, I.; Targett, T. A.; Wagg, J.; Wilson, G. W.; Xu, L.; Yun, M.

    2013-04-01

    We utilized the JCMT/AzTEC 1.1mm maps and catalogues from Austermann et al. (2010, Cat. J/MNRAS/401/160). These data cover 0.7deg2 to an rms depth of 0.9-1.7mJy/beam. We selected all 148 sources presented by Austermann et al. (2010, Cat. J/MNRAS/401/160) with signal-to-noise ratios (S/Ns) > 3.5, and adopted the statistically deboosted 1.1mm flux densities. The VLA 1.4GHz and GMRT 0.61GHz radio data were taken from Ivison et al. (2005MNRAS.364.1025I, 2007, Cat. J/MNRAS/380/199) and Ibar et al. (2009, Cat. J/MNRAS/397/281, 2010MNRAS.401L..53I), respectively. The mid-IR Spitzer data in the Lockman Hole East field are from programmes PID 81 (PI: G. Rieke) and PID 50249 (PI: E. Egami), described in Egami et al. (2004ApJS..154..130E) and Dye et al. (2008MNRAS.386.1107D), whereas in the UDS field the mid-IR data are from the Spitzer Public Legacy Survey of the UKIDSS UDS (PI: J. Dunlop, http://ssc.spitzer.caltech.edu/spitzermission/observingprograms/ legacy/spuds/) described in Caputi et al. (2011MNRAS.413..162C). The optical data in both fields were obtained with Subaru/SuprimeCam, as described in Dye et al. (2006MNRAS.372.1227D) and Furusawa et al. (2008, Cat. J/ApJS/176/1). The near-IR data in both fields are provided by the UKIRT Infrared Deep Sky Survey (UKIDSS; Lawrence et al. 2007, Cat. II/314) with the SXDF/UDS field benefitting from the ultradeep J, H, K coverage provided by the UDS (e.g. Cirasuolo et al. 2010MNRAS.401.1166C), while the Lockman Hole East field is part of the somewhat shallower UKIDSS DXS (Warren et al., 2007MNRAS.375..213W). (5 data files).

  14. Shades of Gray.

    ERIC Educational Resources Information Center

    Nelson, John C.; Calibeo, Thomas E.

    1998-01-01

    A university's financing choices cover many shades of gray. Some off-balance-sheet financing uses no debt capacity, while others represent or imply full financial commitment. Many others fall in between. The choices made by a number of institutions in financing facility expansions or improvements are discussed, and the Moody's Investors Service…

  15. Tints, Shades and Frost

    ERIC Educational Resources Information Center

    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…

  16. Shaded Relief, Kamchatka Peninsula, Russia

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This topographic image shows the western side of the volcanically active Kamchatka Peninsula, Russia. The data are from the first C-band mapping swath of the Shuttle Radar Topography Mission (SRTM). On the left side are four rivers, which flow northwest to the Sea of Okhotsk. These rivers are, from the south to north, Tigil, Amanina, Voyampolka, and Zhilovaya. The broad, flat floodplains of the rivers are shown in blue. These rivers are important spawning grounds for salmon. In the right side of the image is the Sredinnyy Khrebet, the volcanic mountain range that makes up the 3spine2 of the peninsula. The cluster of hills to the lower right is a field of small dormant volcanoes. High resolution SRTM topographic data will be used by geologists to study how volcanoes form and understand the hazards posed by future eruptions.

    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. 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 antenna and

  17. Shape from Shading in Pigeons

    ERIC Educational Resources Information Center

    Cook, Robert G.; Qadri, Muhammad A. J.; Kieres, Art; Commons-Miller, Nicholas

    2012-01-01

    Light is the origin of vision. The pattern of shading reflected from object surfaces is one of several optical features that provide fundamental information about shape and surface orientation. To understand how surface and object shading is processed by birds, six pigeons were tested with differentially illuminated convex and concave curved…

  18. Perceived depth from shading boundaries.

    PubMed

    Kim, Juno; Anstis, Stuart

    2016-01-01

    Shading is well known to provide information the visual system uses to recover the three-dimensional shape of objects. We examined conditions under which patterns in shading promote the experience of a change in depth at contour boundaries, rather than a change in reflectance. In Experiment 1, we used image manipulation to illuminate different regions of a smooth surface from different directions. This manipulation imposed local differences in shading direction across edge contours (delta shading). We found that increasing the angle of delta shading, from 0° to 180°, monotonically increased perceived depth across the edge. Experiment 2 found that the perceptual splitting of shading into separate foreground and background surfaces depended on an assumed light source from above prior. Image regions perceived as foreground structures in upright images appeared farther in depth when the same images were inverted. We also found that the experienced break in surface continuity could promote the experience of amodal completion of colored contours that were ambiguous as to their depth order (Experiment 3). These findings suggest that the visual system can identify occlusion relationships based on monocular variations in local shading direction, but interprets this information according to a light source from above prior of midlevel visual processing.

  19. Perceived depth from shading boundaries.

    PubMed

    Kim, Juno; Anstis, Stuart

    2016-01-01

    Shading is well known to provide information the visual system uses to recover the three-dimensional shape of objects. We examined conditions under which patterns in shading promote the experience of a change in depth at contour boundaries, rather than a change in reflectance. In Experiment 1, we used image manipulation to illuminate different regions of a smooth surface from different directions. This manipulation imposed local differences in shading direction across edge contours (delta shading). We found that increasing the angle of delta shading, from 0° to 180°, monotonically increased perceived depth across the edge. Experiment 2 found that the perceptual splitting of shading into separate foreground and background surfaces depended on an assumed light source from above prior. Image regions perceived as foreground structures in upright images appeared farther in depth when the same images were inverted. We also found that the experienced break in surface continuity could promote the experience of amodal completion of colored contours that were ambiguous as to their depth order (Experiment 3). These findings suggest that the visual system can identify occlusion relationships based on monocular variations in local shading direction, but interprets this information according to a light source from above prior of midlevel visual processing. PMID:27271807

  20. Technology reviews: Shading systems

    SciTech Connect

    Schuman, J.; Rubinstein, F.; Papamichael, K.; Beltran, L.; Lee, E.S.; Selkowitz, S.

    1992-09-01

    We present a representative review of existing, emerging, and future technology options in each of five hardware and systems areas in envelope and lighting technologies: lighting systems, glazing systems, shading systems, daylighting optical systems, and dynamic curtain wall systems. The term technology is used here to describe any design choice for energy efficiency, ranging from individual components to more complex systems to general design strategies. The purpose of this task is to characterize the state of the art in envelope and lighting technologies in order to identify those with promise for advanced integrated systems, with an emphasis on California commercial buildings. For each technology category, the following activities have been attempted to the extent possible: Identify key performance characteristics and criteria for each technology. Determine the performance range of available technologies. Identify the most promising technologies and promising trends in technology advances. Examine market forces and market trends. Develop a continuously growing in-house database to be used throughout the project. A variety of information sources have been used in these technology characterizations, including miscellaneous periodicals, manufacturer catalogs and cut sheets, other research documents, and data from previous computer simulations. We include these different sources in order to best show the type and variety of data available, however publication here does not imply our guarantee of these data. Within each category, several broad classes are identified, and within each class we examine the generic individual technologies that fall into that class.

  1. [Effects of shading on dry matter accumulation and nutrient absorption of summer maize].

    PubMed

    Cui, Hai-Yan; Jin, Li-Bin; Li, Bo; Dong, Shu-Ting; Liu, Peng; Zhao, Bin; Zhang, Ji-Wang

    2013-11-01

    Taking summer maize cultivars Zhenjie 2 (ZJ2), Denghai 605 (DH605), and Zhengdan 958 (ZD958) as test materials, a field trial was conducted to study the effects of shading on the dry matter accumulation and nitrogen (N), phosphorus (P) and potassium (K) absorption of summer maize. Four treatments were installed, i. e., shading from flowering stage to maturity stage (S1), shading from six-leaf stage to flowering stage (S2), shading all through the growth season (S3), and no shading (CK). After shading, the grain yield and dry matter accumulation decreased significantly, and the decrement was related to shading period, showing S3 > S1 > S2. The grain yield in treatments S1, S2, and S3 was averagely 61.6%, 25.3%, and 92.8% lower than that of CK, respectively, indicating that the effects of shading after flowering were greater than those of shading before flowering. The responses of different cultivars to shading presented a similar trend. The nutrient absorption of summer maize before flowering stage showed K > N > P, and the nutrient absorption amount of whole plant showed N>K>P. After shading, the N and P absorption decreased significantly. The plant relative N and P absorption in different treatments had somewhat increase, because the decrement of dry matter accumulation after shading was larger than that of N and P absorption, as compared with the control. After shading, the plant K absorption decreased significantly, and the decrement in S2 was larger than that of dry matter accumulation. Shading before flowering stage had larger effects on the plant K absorption than on the N and P absorption.

  2. A direct approach for quantifying stream shading

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Excessive stream water temperature causes thermal stress in fish and invertebrates, decreases dissolved oxygen, and encourages bacterial and algal growth. Solar radiation affects stream temperature. Shade cast by riparian vegetation reduces thermal inputs to stream water. Stream shading standards...

  3. Cotyledon-Generated Auxin Is Required for Shade-Induced Hypocotyl Growth in Brassica rapa.

    PubMed

    Procko, Carl; Crenshaw, Charisse Michelle; Ljung, Karin; Noel, Joseph Patrick; Chory, Joanne

    2014-06-01

    Plant architecture is optimized for the local light environment. In response to foliar shade or neighbor proximity (low red to far-red light), some plant species exhibit shade-avoiding phenotypes, including increased stem and hypocotyl growth, which increases the likelihood of outgrowing competitor plants. If shade persists, early flowering and the reallocation of growth resources to stem elongation ultimately affect the yield of harvestable tissues in crop species. Previous studies have shown that hypocotyl growth in low red to far-red shade is largely dependent on the photoreceptor phytochrome B and the phytohormone auxin. However, where shade is perceived in the plant and how auxin regulates growth spatially are less well understood. Using the oilseed and vegetable crop species Brassica rapa, we show that the perception of low red to far-red shade by the cotyledons triggers hypocotyl cell elongation and auxin target gene expression. Furthermore, we find that following shade perception, elevated auxin levels occur in a basipetal gradient away from the cotyledons and that this is coincident with a gradient of auxin target gene induction. These results show that cotyledon-generated auxin regulates hypocotyl elongation. In addition, we find in mature B. rapa plants that simulated shade does not affect seed oil composition but may affect seed yield. This suggests that in field settings where mutual shading between plants may occur, a balance between plant density and seed yield per plant needs to be achieved for maximum oil yield, while oil composition might remain constant.

  4. Visual vs. Spectrophotometric Methods for Shade Selection.

    PubMed

    Glockner, Karl; Glockner, Karl; Haiderer, Bernd

    2015-09-01

    The differences in tooth colour are important factors in the esthetic dentistry. The aim of this study was to determine the tooth colour using visual methods under natural light and "Easy Shade" device. Five hundred patients of Dental Clinic Graz Austria were selected for this study. The results of this study showed that the shade matching using "Easy Shade" device were not better than shade matching with visual methods under natural light. No difference was found between visual and digital methods in the selection of a tooth shade.

  5. Shade, leaf growth and crown development of Quercus rubra, Quercus velutina, Prunus serotina and Acer rubrum seedlings.

    PubMed

    Gottschalk, Kurt W.

    1994-01-01

    The study was conducted in an open field to determine the optimum irradiance for establishment and growth of two oak species and two major associated woody species. Half-sib seedlings of black cherry (Prunus serotina Ehrh.), red maple (Acer rubrum L.), northern red oak (Quercus rubra L.) and black oak (Q. velutina Lam.) were grown for two years under shade-cloth tents. Eight shade treatments (94, 70, 57, 45, 37, 27, 20 and 8% of full sunlight) with three replications each were used. Measurements were made on seedlings harvested at the end of the first and second growing seasons. In the second year, shading significantly decreased the number of leaves for all species except black cherry, but only significantly decreased leaf area in northern red oak. Shading significantly decreased average leaf size of red maple. Average leaf size of black cherry was largest in the intermediate shade treatments and decreased significantly with increased and decreased shade. Leaf weight/leaf area (mg cm(-2)) increased significantly in a quadratic pattern with decreasing shade for all four species. Leaf area ratio (cm(2) g(-1)) decreased significantly with decreasing shade for all species except red maple in the first year and black oak in the second year. Total branch development increased significantly with decreasing shade in red maple and northern red oak, whereas indeterminate branches increased significantly with decreasing shade only in black cherry, and short branches increased significantly with decreasing shade only in red maple. PMID:14967644

  6. Shaded Relief Color Wrapped, Kamchatka Peninsula, Russia

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This shaded relief topographic image shows the western side of the volcanically active Kamchatka Peninsula, Russia. The data are from the first C-band mapping swath of the Shuttle Radar Topography Mission (SRTM). On the left side are five rivers, which flow northwest to the Sea of Okhotsk. These rivers are, from the south to north, Tigil, Amanina, Voyampolka, Zhilovaya, and Kakhtana. The broad, flat floodplains of the rivers are shown in yellow. These rivers are important spawning grounds for salmon. In the right side of the image is the Sredinnyy Khrebet, the volcanic mountain range that makes up the 3spine2 of the peninsula. The cluster of hills to the lower right is a field of small dormant volcanoes. High resolution SRTM topographic data will be used by geologists to study how volcanoes form and understand the hazards posed by future eruptions.

    This image was generated using topographic data from the Shuttle Radar Topography Mission. Colors show the elevation as measured by SRTM. Each cycle of colors (from red through green back to red) represents an equal amount of elevation difference (400 meters, or 1300 feet)similar to contour lines on a standard topographic map. This image contains about 2300 meters (7500 feet) of total relief. For the shading, 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. 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

  7. Topography from shading and stereo

    NASA Technical Reports Server (NTRS)

    Horn, Berthold K. P.

    1994-01-01

    Methods exploiting photometric information in images that have been developed in machine vision can be applied to planetary imagery. Integrating shape from shading, binocular stereo, and photometric stereo yields a robust system for recovering detailed surface shape and surface reflectance information. Such a system is useful in producing quantitative information from the vast volume of imagery being received, as well as in helping visualize the underlying surface.

  8. Effects of Shading on Starch Pasting Characteristics of Indica Hybrid Rice (Oryza sativa L.)

    PubMed Central

    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. PMID:23861872

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

    PubMed

    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.

  10. Field-Grown Grapevine Berries Use Carotenoids and the Associated Xanthophyll Cycles to Acclimate to UV Exposure Differentially in High and Low Light (Shade) Conditions

    PubMed Central

    Joubert, Chandré; Young, Philip R.; Eyéghé-Bickong, Hans A.; Vivier, Melané A.

    2016-01-01

    Light quantity and quality modulate grapevine development and influence berry metabolic processes. Here we studied light as an information signal for developing and ripening grape berries. A Vitis vinifera Sauvignon Blanc field experiment was used to identify the impacts of UVB on core metabolic processes in the berries under both high light (HL) and low light (LL) microclimates. The primary objective was therefore to identify UVB-specific responses on berry processes and metabolites and distinguish them from those responses elicited by variations in light incidence. Canopy manipulation at the bunch zone via early leaf removal, combined with UVB-excluding acrylic sheets installed over the bunch zones resulted in four bunch microclimates: (1) HL (control); (2) LL (control); (3) HL with UVB attenuation and (4) LL with UVB attenuation. Metabolite profiles of three berry developmental stages showed predictable changes to known UV-responsive compound classes in a typical UV acclimation (versus UV damage) response. Interestingly, the berries employed carotenoids and the associated xanthophyll cycles to acclimate to UV exposure and the berry responses differed between HL and LL conditions, particularly in the developmental stages where berries are still photosynthetically active. The developmental stage of the berries was an important factor to consider in interpreting the data. The green berries responded to the different exposure and/or UVB attenuation signals with metabolites that indicate that the berries actively managed its metabolism in relation to the exposure levels, displaying metabolic plasticity in the photosynthesis-related metabolites. Core processes such as photosynthesis, photo-inhibition and acclimation were maintained by differentially modulating metabolites under the four treatments. Ripe berries also responded metabolically to the light quality and quantity, but mostly formed compounds (volatiles and polyphenols) that have direct antioxidant and/or

  11. Field-Grown Grapevine Berries Use Carotenoids and the Associated Xanthophyll Cycles to Acclimate to UV Exposure Differentially in High and Low Light (Shade) Conditions.

    PubMed

    Joubert, Chandré; Young, Philip R; Eyéghé-Bickong, Hans A; Vivier, Melané A

    2016-01-01

    Light quantity and quality modulate grapevine development and influence berry metabolic processes. Here we studied light as an information signal for developing and ripening grape berries. A Vitis vinifera Sauvignon Blanc field experiment was used to identify the impacts of UVB on core metabolic processes in the berries under both high light (HL) and low light (LL) microclimates. The primary objective was therefore to identify UVB-specific responses on berry processes and metabolites and distinguish them from those responses elicited by variations in light incidence. Canopy manipulation at the bunch zone via early leaf removal, combined with UVB-excluding acrylic sheets installed over the bunch zones resulted in four bunch microclimates: (1) HL (control); (2) LL (control); (3) HL with UVB attenuation and (4) LL with UVB attenuation. Metabolite profiles of three berry developmental stages showed predictable changes to known UV-responsive compound classes in a typical UV acclimation (versus UV damage) response. Interestingly, the berries employed carotenoids and the associated xanthophyll cycles to acclimate to UV exposure and the berry responses differed between HL and LL conditions, particularly in the developmental stages where berries are still photosynthetically active. The developmental stage of the berries was an important factor to consider in interpreting the data. The green berries responded to the different exposure and/or UVB attenuation signals with metabolites that indicate that the berries actively managed its metabolism in relation to the exposure levels, displaying metabolic plasticity in the photosynthesis-related metabolites. Core processes such as photosynthesis, photo-inhibition and acclimation were maintained by differentially modulating metabolites under the four treatments. Ripe berries also responded metabolically to the light quality and quantity, but mostly formed compounds (volatiles and polyphenols) that have direct antioxidant and

  12. Field-Grown Grapevine Berries Use Carotenoids and the Associated Xanthophyll Cycles to Acclimate to UV Exposure Differentially in High and Low Light (Shade) Conditions.

    PubMed

    Joubert, Chandré; Young, Philip R; Eyéghé-Bickong, Hans A; Vivier, Melané A

    2016-01-01

    Light quantity and quality modulate grapevine development and influence berry metabolic processes. Here we studied light as an information signal for developing and ripening grape berries. A Vitis vinifera Sauvignon Blanc field experiment was used to identify the impacts of UVB on core metabolic processes in the berries under both high light (HL) and low light (LL) microclimates. The primary objective was therefore to identify UVB-specific responses on berry processes and metabolites and distinguish them from those responses elicited by variations in light incidence. Canopy manipulation at the bunch zone via early leaf removal, combined with UVB-excluding acrylic sheets installed over the bunch zones resulted in four bunch microclimates: (1) HL (control); (2) LL (control); (3) HL with UVB attenuation and (4) LL with UVB attenuation. Metabolite profiles of three berry developmental stages showed predictable changes to known UV-responsive compound classes in a typical UV acclimation (versus UV damage) response. Interestingly, the berries employed carotenoids and the associated xanthophyll cycles to acclimate to UV exposure and the berry responses differed between HL and LL conditions, particularly in the developmental stages where berries are still photosynthetically active. The developmental stage of the berries was an important factor to consider in interpreting the data. The green berries responded to the different exposure and/or UVB attenuation signals with metabolites that indicate that the berries actively managed its metabolism in relation to the exposure levels, displaying metabolic plasticity in the photosynthesis-related metabolites. Core processes such as photosynthesis, photo-inhibition and acclimation were maintained by differentially modulating metabolites under the four treatments. Ripe berries also responded metabolically to the light quality and quantity, but mostly formed compounds (volatiles and polyphenols) that have direct antioxidant and

  13. Overexpression of phytochrome A and its hyperactive mutant improves shade tolerance and turf quality in creeping bentgrass and zoysiagrass.

    PubMed

    Ganesan, Markkandan; Han, Yun-Jeong; Bae, Tae-Woong; Hwang, Ok-Jin; Chandrasekhar, Thummala; Chandrasekkhar, Thummala; Shin, Ah-Young; Goh, Chang-Hyo; Nishiguchi, Satoshi; Song, In-Ja; Lee, Hyo-Yeon; Kim, Jeong-Il; Song, Pill-Soon

    2012-10-01

    Phytochrome A (phyA) in higher plants is known to function as a far-red/shade light-sensing photoreceptor in suppressing shade avoidance responses (SARs) to shade stress. In this paper, the Avena PHYA gene was introduced into creeping bentgrass (Agrostis stolonifera L.) and zoysiagrass (Zoysia japonica Steud.) to improve turf quality by suppressing the SARs. In addition to wild-type PHYA, a hyperactive mutant gene (S599A-PHYA), in which a phosphorylation site involved in light-signal attenuation was removed, was also transformed into the turfgrasses. Phenotypic traits of the transgenic plants were compared to assess the suppression of SARs under a simulated shade condition and outdoor field conditions after three growth seasons. Under the shade condition, the S599A-PhyA transgenic creeping bentgrass plants showed shade avoidance-suppressing phenotypes with a 45 % shorter leaf lengths, 24 % shorter internode lengths, and twofold increases in chlorophyll concentrations when compared with control plants. Transgenic zoysiagrass plants overexpressing S599A-PHYA also showed shade-tolerant phenotypes under the shade condition with reductions in leaf length (15 %), internode length (30 %), leaf length/width ratio (19 %) and leaf area (22 %), as well as increases in chlorophyll contents (19 %) and runner lengths (30 %) compared to control plants. The phenotypes of transgenic zoysiagrass were also investigated in dense field habitats, and the transgenic turfgrass exhibited shade-tolerant phenotypes similar to those observed under laboratory shade conditions. Therefore, the present study suggests that the hyperactive phyA is effective for the development of shade-tolerant plants, and that the shade tolerance nature is sustained under field conditions.

  14. Partial shade stress test for thin-film photovoltaic modules

    NASA Astrophysics Data System (ADS)

    Silverman, Timothy J.; Deceglie, Michael G.; Deline, Chris; Kurtz, Sarah

    2015-09-01

    Partial shade of monolithic thin-film PV modules can cause reverse-bias conditions leading to permanent damage. In this work, we introduce a partial shade stress test for thin-film PV modules that quantifies permanent performance loss. The test reproduces shading and loading conditions that may occur in the field. It accounts for reversible light-induced performance changes and for the effects of light-enhanced reverse breakdown. We simulated the test procedure using a computer model that predicts the local voltage, current and temperature stress resulting from partial shade. We also performed the test on three commercial module types. Each module type we tested suffered permanent damage during masked ash testing totaling < 2 s of light exposure. During the subsequent stress test these module types lost 4%{11% in Pmp due to widespread formation of new shunts. One module type showed a substantial worsening of the Pmp loss upon light stabilization, underscoring the importance of this practice for proper quantification of damage.

  15. The shading cue in context

    PubMed Central

    Wagemans, Johan; van Doorn, Andrea J; Koenderink, Jan J

    2010-01-01

    The shading cue is supposed to be a major factor in monocular stereopsis. However, the hypothesis is hardly corroborated by available data. For instance, the conventional stimulus used in perception research, which involves a circular disk with monotonic luminance gradient on a uniform surround, is theoretically ‘explained’ by any quadric surface, including spherical caps or cups (the conventional response categories), cylindrical ruts or ridges, and saddle surfaces. Whereas cylindrical ruts or ridges are reported when the outline is changed from circular to square, saddle surfaces are never reported. We introduce a method that allows us to differentiate between such possible responses. We report observations on a number of variations of the conventional stimulus, including variations of shape and quality of the boundary, and contexts that allow the observer to infer illumination direction. We find strong and expected influences of outline shape, but, perhaps surprisingly, we fail to find any influence of context, and only partial influence of outline quality. Moreover, we report appreciable differences within the generic population. We trace some of the idiosyncrasies (as compared to shape from shading algorithms) of the human observer to generic properties of the environment, in particular the fact that many objects are limited in size and elliptically convex over most of their boundaries. PMID:23145221

  16. Blue light regulated shade avoidance.

    PubMed

    Keuskamp, Diederik H; Keller, Mercedes M; Ballaré, Carlos L; Pierik, Ronald

    2012-04-01

    Most plants grow in dense vegetation with the risk of being out-competed by neighboring plants. These neighbors can be detected not only through the depletion in light quantity that they cause, but also through the change in light quality, which plants perceive using specific photoreceptors. Both the reduction of the red:far-red ratio and the depletion of blue light are signals that induce a set of phenotypic traits, such as shoot elongation and leaf hyponasty, which increase the likelihood of light capture in dense plant stands. This set of phenotypic responses are part of the so called shade avoidance syndrome (SAS). This addendum discusses recent findings on the regulation of the SAS of Arabidopsis thaliana upon blue light depletion. Keller et al. and Keuskamp et al. show that the low blue light attenuation induced shade avoidance response of seedling and rosette-stage A. thaliana plants differ in their hormonal regulation. These studies also show there is a regulatory overlap with the R:FR-regulated SAS.

  17. New entrance shade design for SIRTF

    NASA Technical Reports Server (NTRS)

    Davis, Paul K.

    1989-01-01

    A new design for the entrance shade for the Space Infrared Telescope Facility (SIRTF) is presented. The evolution of the entrance shade began with a simple frustum, symmetrical about the telescope axis, when SIRTF was expected to be Shuttle-attached. With the change to a free-flying SIRTF this frustum was cut off at an angle. The telescope will be operated so that whenever not in the earth's shadow the high side is kept toward the sun. However, the entrance shade interior itself will be so warm that the optics, including the secondary mirror and its mechanisms and support structure, will be restricted to the rear part of the barrel, termed the aftbaffle, which is shaded from the interior of the entrance shade by the forebaffle. This is best accomplished by the most recent design in which the axis of the entrance shade is offset from the telescope axis. This results in a shorter entrance shade, shorter forebaffle, and a shaded region within the barrel which is symmetrical about the telescope axis. All of these are advantageous.

  18. Effect of shade on atmospheric oxidants (smog)

    SciTech Connect

    Stewart, W.S.; Wilken, D.H.

    1985-01-01

    A series of experiments utilizing atmospheric smog were conducted comparing simultaneously the oxidant level in sunlight and under shade. From the results of the experiments, it is suggested that the undesirable effects of smog in a localized area may be reduced by the planting of shade trees, vines, shrubs and encouraging a denser growth of vegetation.

  19. Cotyledon-Generated Auxin Is Required for Shade-Induced Hypocotyl Growth in Brassica rapa1[C][W][OPEN

    PubMed Central

    Procko, Carl; Crenshaw, Charisse Michelle; Ljung, Karin; Noel, Joseph Patrick; Chory, Joanne

    2014-01-01

    Plant architecture is optimized for the local light environment. In response to foliar shade or neighbor proximity (low red to far-red light), some plant species exhibit shade-avoiding phenotypes, including increased stem and hypocotyl growth, which increases the likelihood of outgrowing competitor plants. If shade persists, early flowering and the reallocation of growth resources to stem elongation ultimately affect the yield of harvestable tissues in crop species. Previous studies have shown that hypocotyl growth in low red to far-red shade is largely dependent on the photoreceptor phytochrome B and the phytohormone auxin. However, where shade is perceived in the plant and how auxin regulates growth spatially are less well understood. Using the oilseed and vegetable crop species Brassica rapa, we show that the perception of low red to far-red shade by the cotyledons triggers hypocotyl cell elongation and auxin target gene expression. Furthermore, we find that following shade perception, elevated auxin levels occur in a basipetal gradient away from the cotyledons and that this is coincident with a gradient of auxin target gene induction. These results show that cotyledon-generated auxin regulates hypocotyl elongation. In addition, we find in mature B. rapa plants that simulated shade does not affect seed oil composition but may affect seed yield. This suggests that in field settings where mutual shading between plants may occur, a balance between plant density and seed yield per plant needs to be achieved for maximum oil yield, while oil composition might remain constant. PMID:24891610

  20. Series-connected shaded modules to address partial shading conditions in SPV systems

    NASA Astrophysics Data System (ADS)

    Pareek, Smita; Dahiya, Ratna

    2016-03-01

    With the progress of technology and reduced cost of PV cells, the PV systems are being installed in many countries, including India. Even though this method of power generation has sufficient potential but its effective utilization is still lacking. This is because the output power of PV cells depends on many factors like insolation, temperature, climate conditions prevailing nearby, aging, using modules from different technologies/manufacturers or partial shading conditions. Among these factors, partial shading causes major reduction in output power despite the size of PV systems. As a result, the produced power is lower than the expected value. The connection of modules to each other has great impact on output power if they are prone to partial shading conditions. In this paper, PV arrays are investigated under partial shading conditions. The results show that partial shading losses can be minimized by connecting shaded modules in series rather than in parallel.

  1. Partial Shade Stress Test for Thin-Film Photovoltaic Modules: Preprint

    SciTech Connect

    Silverman, Timothy J.; Deceglie, Michael G.; Deline, Chris; Kurtz, Sarah

    2015-09-02

    Partial shade of monolithic thin-film PV modules can cause reverse-bias conditions leading to permanent damage. In this work, we propose a partial shade stress test for thin-film PV modules that quantifies permanent performance loss. We designed the test with the aid of a computer model that predicts the local voltage, current and temperature stress that result from partial shade. The model predicts the module-scale interactions among the illumination pattern, the electrical properties of the photovoltaic material and the thermal properties of the module package. The test reproduces shading and loading conditions that may occur in the field. It accounts for reversible light-induced performance changes and for additional stress that may be introduced by light-enhanced reverse breakdown. We present simulated and experimental results from the application of the proposed test.

  2. Seeds Use Temperature Cues to Ensure Germination under Nurse-plant Shade in Xeric Kalahari Savannah

    PubMed Central

    Kos, Martijn; Poschlod, Peter

    2007-01-01

    Background and Aims In arid environments many plant species are found associated with the canopies of woody perennials. Favourable conditions for establishment under canopies are likely to be associated with shade, but under canopies shade is distributed patchily and differs in quality. Diurnal temperature fluctuations and maximum temperatures could be reliable indicators of safe sites. Here, an examination is made as to whether canopy-associated species use temperature cues to germinate in shade patches, rather than matrix areas between trees. Methods The study was carried out in arid southern Kalahari savannah (Republic of South Africa). Perennial and annual species associated with Acacia erioloba trees and matrix species were germinated at temperature regimes resembling shaded and unshaded conditions. Soil temperature was measured in the field. Key Results Germination of all fleshy-fruited perennial acacia-associated species and two annual acacia-associated species was inhibited by the temperature regime resembling unshaded conditions compared with at least one of the regimes resembling shaded conditions. Inhibition in perennials decreased with seed mass, probably reflecting that smaller seedlings are more vulnerable to drought. Germination of matrix species was not inhibited by the unshaded temperature regime and in several cases it increased germination compared with shaded temperature regimes or constant temperature. Using phylogenetically independent contrasts a significant positive relationship was found between canopy association and the germination at shade temperatures relative to unshaded temperatures. Conclusions The data support the hypothesis that canopy species have developed mechanisms to prevent germination in open sun conditions. The results and data from the literature show that inhibition of germination at temperature regimes characteristic of open sun conditions can be found in fleshy-fruited species of widely divergent taxonomic groups. It is

  3. Effects of Nitrogen and Shading on Root Morphologies, Nutrient Accumulation, and Photosynthetic Parameters in Different Rice Genotypes.

    PubMed

    Pan, Shenggang; Liu, Haidong; Mo, Zhaowen; Patterson, Bob; Duan, Meiyang; Tian, Hua; Hu, Shuijing; Tang, Xiangru

    2016-01-01

    Nitrogen availability and illumination intensity are two key factors which affect rice growth. However, their influences on total nitrogen accumulation, photosynthetic rate, root morphologies, and yields are not fully understood. We conducted two field experiments to (1) evaluate the effects of shading under different N treatments on photosynthetic parameters, root morphologies, total nutrient accumulation, and grain yields of rice; and (2) elucidate the relationship between total nutrient accumulation and root morphologies under different shading conditions and nitrogen treatments. Three nitrogen rates, three shading treatments, and three different rice cultivars were used in two field experiments. Double shading during the grain-filling stage decreased total nutrient accumulation, altered root morphological characteristics, and decreased yields in rice. There were also significant interaction effects between nitrogen and shading on photosynthetic rate, transpiration rate, and total root length, root superficial area, and root volume. Significant interactions were found among cultivars and shading for photosynthetic rate and transpiration rate. Correlation analysis revealed that total nitrogen accumulation (TNA) and potassium accumulation (TKA) were significantly positively correlated with total root length, root superficial area, and root volume. N application could alleviate the detrimental effects of shading on total nutrient accumulation and grain yield in rice. PMID:27557779

  4. Effects of Nitrogen and Shading on Root Morphologies, Nutrient Accumulation, and Photosynthetic Parameters in Different Rice Genotypes.

    PubMed

    Pan, Shenggang; Liu, Haidong; Mo, Zhaowen; Patterson, Bob; Duan, Meiyang; Tian, Hua; Hu, Shuijing; Tang, Xiangru

    2016-08-25

    Nitrogen availability and illumination intensity are two key factors which affect rice growth. However, their influences on total nitrogen accumulation, photosynthetic rate, root morphologies, and yields are not fully understood. We conducted two field experiments to (1) evaluate the effects of shading under different N treatments on photosynthetic parameters, root morphologies, total nutrient accumulation, and grain yields of rice; and (2) elucidate the relationship between total nutrient accumulation and root morphologies under different shading conditions and nitrogen treatments. Three nitrogen rates, three shading treatments, and three different rice cultivars were used in two field experiments. Double shading during the grain-filling stage decreased total nutrient accumulation, altered root morphological characteristics, and decreased yields in rice. There were also significant interaction effects between nitrogen and shading on photosynthetic rate, transpiration rate, and total root length, root superficial area, and root volume. Significant interactions were found among cultivars and shading for photosynthetic rate and transpiration rate. Correlation analysis revealed that total nitrogen accumulation (TNA) and potassium accumulation (TKA) were significantly positively correlated with total root length, root superficial area, and root volume. N application could alleviate the detrimental effects of shading on total nutrient accumulation and grain yield in rice.

  5. Effects of Nitrogen and Shading on Root Morphologies, Nutrient Accumulation, and Photosynthetic Parameters in Different Rice Genotypes

    PubMed Central

    Pan, Shenggang; Liu, Haidong; Mo, Zhaowen; Patterson, Bob; Duan, Meiyang; Tian, Hua; Hu, Shuijing; Tang, Xiangru

    2016-01-01

    Nitrogen availability and illumination intensity are two key factors which affect rice growth. However, their influences on total nitrogen accumulation, photosynthetic rate, root morphologies, and yields are not fully understood. We conducted two field experiments to (1) evaluate the effects of shading under different N treatments on photosynthetic parameters, root morphologies, total nutrient accumulation, and grain yields of rice; and (2) elucidate the relationship between total nutrient accumulation and root morphologies under different shading conditions and nitrogen treatments. Three nitrogen rates, three shading treatments, and three different rice cultivars were used in two field experiments. Double shading during the grain-filling stage decreased total nutrient accumulation, altered root morphological characteristics, and decreased yields in rice. There were also significant interaction effects between nitrogen and shading on photosynthetic rate, transpiration rate, and total root length, root superficial area, and root volume. Significant interactions were found among cultivars and shading for photosynthetic rate and transpiration rate. Correlation analysis revealed that total nitrogen accumulation (TNA) and potassium accumulation (TKA) were significantly positively correlated with total root length, root superficial area, and root volume. N application could alleviate the detrimental effects of shading on total nutrient accumulation and grain yield in rice. PMID:27557779

  6. Shading reduces coral-disease progression

    NASA Astrophysics Data System (ADS)

    Muller, E. M.; van Woesik, R.

    2009-09-01

    The growing incidence of tropical-marine diseases is attributed to increases in pathogen prevalence and virulence associated with global warming. Additionally, the compromised-host hypothesis suggests that rising ocean temperatures may increase disease activity by making the corals more susceptible to ubiquitous pathogens. We tested the effects of reducing irradiance stress on coral-disease progression rates by shading corals showing signs consistent with white-plague disease. Our results showed that white-plague disease on shaded corals progressed significantly more slowly than on controls. Although the mechanisms are unknown, this study suggests that light intensity influences the rate of coral-disease progression.

  7. Computer simulation of shading and blocking: Discussion of accuracy and recommendations

    SciTech Connect

    Lipps, F.W. )

    1992-04-01

    A field of heliostats suffers losses caused by shading and blocking by neighboring heliostats. The complex geometry of multiple shading and blocking events suggests that a processing code is needed to update the boundary vector for each shading or blocking event. A new version, RSABS, (programmer's manual included) simulates the split-rectangular heliostat. Researchers concluded that the dominant error for the given heliostat geometry is caused by the departure from planarity of the neighboring heliostats. It is recommended that a version of the heliostat simulation be modified to include losses due to nonreflective structural margins, if they occur. Heliostat neighbors should be given true guidance rather than assumed to be parallel, and the resulting nonidentical quadrilateral images should be processed, as in HELIOS, by ignoring overlapping events, rare in optimized fields.

  8. Gray-shading for the SD-4060 graphics device

    NASA Technical Reports Server (NTRS)

    Gloeckler, C.

    1975-01-01

    Grays, a FORTRAN program, is described which will generate gray shading for the SD-4060 graphics device. The program produces 10 shades of gray ranging from no shading at all to complete coverage of the film frame. The graphing capabilities are summarized and illustrated. The figures displayed are representative of the microfilm output, but the distinction between various intensities is much clearer on the film, especially at the more intense shading.

  9. Shape from shading in starlings (Sturnus vulgaris).

    PubMed

    Qadri, Muhammad A J; Romero, L Michael; Cook, Robert G

    2014-11-01

    Birds behave as if they quickly and accurately perceive an object-filled visual world. Beyond the extensive research with pigeons, however, there is a large and important gap in our knowledge about the mechanisms of object perception and recognition in other avian visual systems. The pattern of shading reflected from the surfaces of objects is one important optical feature that provides fundamental information about shape. To better understand how surface and object shading is processed by a passerine species, 5 starlings were tested with differentially illuminated convex and concave curved surfaces in 3 experiments using a simultaneous visual discrimination procedure. Starlings rapidly learned this shape-from-shading discrimination independent of varied lighting direction, surface color, and camera perspective. Variations in the pattern of lighting through experimental manipulations of camera perspective, surface height, contrast, material specularity, and surface shape were consistent with the hypothesis that the starlings perceived these illuminated surfaces as having 3-dimensional shape, similar to results previously collected with pigeons. These similarities across different orders of birds indicate that the relative shading of objects in a visual scene is a highly salient feature for shape processing in birds and is likely a highly conserved visual process that is widely distributed within this class of animal. PMID:25111630

  10. Shape from Shading in Starlings (Sturnus vulgaris)

    PubMed Central

    Qadri, Muhammad A.; Romero, L. Michael; Cook, Robert G.

    2014-01-01

    Birds behave as if they quickly and accurately perceive an object-filled visual world. Beyond the extensive research with pigeons, however, there is a large and important gap in our knowledge about the mechanisms of object perception and recognition in other avian visual systems. The pattern of shading reflected from object surfaces is one important optical feature providing fundamental information about shape. To better understand how surface and object shading is processed by a passerine species, five starlings were tested with differentially illuminated convex and concave curved surfaces in three experiments using a simultaneous visual discrimination procedure. Starlings rapidly learned this shape-from-shading discrimination independent of varied lighting direction, surface color, and camera perspective. Variations in the pattern of lighting through experimental manipulations of camera perspective, surface height, contrast, material specularity, and surface shape were consistent with the hypothesis that the starlings perceived these illuminated surfaces as having three-dimensional shape, similar to results previously collected with pigeons. These similarities across different orders of birds indicate that the relative shading for objects in a visual scene is a highly salient feature for shape processing in birds and is likely a highly conserved visual process that is widely distributed within this class of animal. PMID:25111630

  11. 21 CFR 872.3690 - Tooth shade resin material.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tooth shade resin material. 872.3690 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3690 Tooth shade resin material. (a) Identification. Tooth shade resin material is a device composed of materials such as bisphenol-A...

  12. 21 CFR 872.3690 - Tooth shade resin material.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Tooth shade resin material. 872.3690 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3690 Tooth shade resin material. (a) Identification. Tooth shade resin material is a device composed of materials such as bisphenol-A...

  13. 21 CFR 872.3690 - Tooth shade resin material.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Tooth shade resin material. 872.3690 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3690 Tooth shade resin material. (a) Identification. Tooth shade resin material is a device composed of materials such as bisphenol-A...

  14. 21 CFR 872.3690 - Tooth shade resin material.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Tooth shade resin material. 872.3690 Section 872...) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3690 Tooth shade resin material. (a) Identification. Tooth shade resin material is a device composed of materials such as bisphenol-A...

  15. Green light induces shade avoidance symptoms.

    PubMed

    Zhang, Tingting; Maruhnich, Stefanie A; Folta, Kevin M

    2011-11-01

    Light quality and quantity affect plant adaptation to changing light conditions. Certain wavelengths in the visible and near-visible spectrum are known to have discrete effects on plant growth and development, and the effects of red, far-red, blue, and ultraviolet light have been well described. In this report, an effect of green light on Arabidopsis (Arabidopsis thaliana) rosette architecture is demonstrated using a narrow-bandwidth light-emitting diode-based lighting system. When green light was added to a background of constant red and blue light, plants exhibited elongation of petioles and upward leaf reorientation, symptoms consistent with those observed in a shaded light environment. The same green light-induced phenotypes were also observed in phytochrome (phy) and cryptochrome (cry) mutant backgrounds. To explore the molecular mechanism underlying the green light-induced response, the accumulation of shade-induced transcripts was measured in response to enriched green light environments. Transcripts that have been demonstrated to increase in abundance under far-red-induced shade avoidance conditions either decrease or exhibit no change when green light is added. However, normal far-red light-associated transcript accumulation patterns are observed in cryptochrome mutants grown with supplemental green light, indicating that the green-absorbing form of cryptochrome is the photoreceptor active in limiting the green light induction of shade-associated transcripts. These results indicate that shade symptoms can be induced by the addition of green light and that cryptochrome receptors and an unknown light sensor participate in acclimation to the enriched green environment.

  16. Shading Influence on the Sterol Balance of Nicotiana tabacum L. 1

    PubMed Central

    Grunwald, Claus

    1978-01-01

    Tobacco plants (Nicotiana tabacum L.) were grown in the field and the apex was removed at the 42-day stage. Shading screens were set up which produced 0, 26, 67, and 90% shade. Plants were grown an additional 25 days before leaves from top, middle, and bottom stalk positions were harvested. Each leaf group was analyzed for free sterol, steryl ester, steryl glycoside, and acylsteryl glycoside. The free sterol content was lowest in top leaves and highest in bottom leaves; however, the top leaves had more steryl ester than the bottom leaves. Leaf position had no effect on steryl glycosides and acylsteryl glycosides. Shading did not influence the level of any sterol class; but in general, shading increased stigmasterol and decreased sitosterol. This trend was observed for all sterol classes, and the free sterols showed the largest and most consistent change. The younger top leaves showed a greater response than the older bottom leaves, but bottom leaves always had more stigmasterol than sitosterol even without shade. PMID:16660242

  17. Sun-shades as a passive cooling element

    SciTech Connect

    Shaviv, E

    1980-01-01

    A discussion of the importance of proper sun-shade design is presented by showing results of thermal performance evaluation of a building with and without sun-shades. The analysis was carried out by using a simulation model developed by Shaviv and Shaviv. The criteria for evaluating sunshades is based on the total energy consumption of the building for cooling, heating, and artificial lighting. We find that the best solution for shading is external sun-shades and we present a method developed by Shaviv for their design. Several designs of external sun-shades are presented.

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

    PubMed

    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. PMID:22083284

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

    PubMed

    Schoonmaker, Amanda L; Lieffers, Victor J; Landhäusser, Simon M

    2014-01-01

    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. PMID:25136823

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

    PubMed

    Schoonmaker, Amanda L; Lieffers, Victor J; Landhäusser, Simon M

    2014-01-01

    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.

  1. Uniform versus Asymmetric Shading Mediates Crown Recession in Conifers

    PubMed Central

    Schoonmaker, Amanda L.; Lieffers, Victor J.; Landhäusser, Simon M.

    2014-01-01

    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. PMID:25136823

  2. Digital Shaded-Relief Image of Alaska

    USGS Publications Warehouse

    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

  3. Technique for making a customized shade guide.

    PubMed

    Askinas, S W; Kaiser, D A

    1979-08-01

    A technique has been presented for making a custom shade guide that provides a direct visual means for conveying color information to the laboratory technician. The technique consists of applying pigment directly to acrylic resin denture teeth using colored drawing pencils. This technique was originated by Dr. Royal Norman of Omaha, Nebraska. One of the authors (S. W. A.) first saw Dr. Norman present it to the USAF Area Dental Laboratory Workshop, Westover AFB, Mass., in 1969.

  4. Impact of Photovoltaic Canopy Shade on Outdoor Thermal Comfort in a Hot Desert City

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

    Shade plays an important role in designing pedestrian-friendly outdoor spaces in hot desert cities. This study investigates the impact of photovoltaic canopy shade on thermal comfort through microclimate observations and field surveys at a pedestrian mall on Arizona State University's Tempe campus. Six stationary sensors under solar canopies and in nearby sun-exposed and tree-shaded locations monitored 5-min temperature and humidity for a year. On selected clear calm days representative of each season, we conducted hourly microclimate transects from 7:00AM to 6:00PM and surveyed 1284 people about their thermal perception, comfort, and preferences. Shade lowered thermal sensation votes by approximately 1 point on the Likert scale, increasing thermal comfort in all seasons except winter. The shade type (tree or solar canopy) did not significantly impact perceived comfort, suggesting that artificial and natural shade are equally efficient in semi-arid desert environments. Globe temperature explained 50% of the variance in thermal sensation votes and was the only statistically significant meteorological predictor. Important non-meteorological factors include adaptation level, gender, thermal comfort vote, thermal preference, season, and time of day. A regression of perceived comfort 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 temperatures felt more comfortable if they had been in air-conditioning 5 minutes 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.

  5. Fine Shades of a Sombrero

    NASA Astrophysics Data System (ADS)

    2000-02-01

    In addition to their scientific value, many of the exposures now being obtained by visiting astronomers to ESO's Very Large Telescope (VLT) are also very beautiful. This is certainly true for this new image of the famous early-type spiral galaxy Messier 104 , widely known as the "Sombrero" (the Mexican hat) because of its particular shape. The colour image was made by a combination of three CCD images from the FORS1 multi-mode instrument on VLT ANTU , recently obtained by Peter Barthel from the Kapteyn Institute (Groningen, The Netherlands) during an observing run at the Paranal Observatory. He and Mark Neeser , also from the Kapteyn Institute, produced the composite images. The galaxy fits perfectly into the 6.8 x 6.8 arcmin 2 field-of-view of the FORS1 camera. A great amount of fine detail is revealed, from the structures in the pronounced dust band in the equatorial plane, to many faint background galaxies that shine through the outer regions. The "Sombrero" is located in the constellation Virgo (The Virgin), at a distance of about 50 million light-years. The overall "sharpness" of this colour image corresponds to about 0.7 arcsec which translates into a resolution of about 170 light-years at that distance. About Messier 104 Messier 104 is the 104th object in the famous catalogue of nebulae by French astronomer Charles Messier (1730 - 1817). It was not included in the first two editions (with 45 objects in 1774; 103 in 1781), but Messier soon thereafter added it by hand in his personal copy as a "very faint nebula". The recession velocity, about 1000 km/sec, was first measured by American astronomer Vesto M. Slipher at the Lowell Observatory in 1912; he was also the first to detect the galaxy's rotation. ESO Press Photo 07c/00 ESO Press Photo 07c/00 [Preview; JPEG: 400 x 307; 59k] [Normal; JPEG: 800 x 614; 308k] [Full-Res; JPEG: 2028 x 1556; 2.3Mb] PR Photo 07c/00 has been processed to show the numerous dust bands in the central plane of the Sombrero galaxy (see

  6. Fine Shades of a Sombrero

    NASA Astrophysics Data System (ADS)

    2000-02-01

    In addition to their scientific value, many of the exposures now being obtained by visiting astronomers to ESO's Very Large Telescope (VLT) are also very beautiful. This is certainly true for this new image of the famous early-type spiral galaxy Messier 104 , widely known as the "Sombrero" (the Mexican hat) because of its particular shape. The colour image was made by a combination of three CCD images from the FORS1 multi-mode instrument on VLT ANTU , recently obtained by Peter Barthel from the Kapteyn Institute (Groningen, The Netherlands) during an observing run at the Paranal Observatory. He and Mark Neeser , also from the Kapteyn Institute, produced the composite images. The galaxy fits perfectly into the 6.8 x 6.8 arcmin 2 field-of-view of the FORS1 camera. A great amount of fine detail is revealed, from the structures in the pronounced dust band in the equatorial plane, to many faint background galaxies that shine through the outer regions. The "Sombrero" is located in the constellation Virgo (The Virgin), at a distance of about 50 million light-years. The overall "sharpness" of this colour image corresponds to about 0.7 arcsec which translates into a resolution of about 170 light-years at that distance. About Messier 104 Messier 104 is the 104th object in the famous catalogue of nebulae by French astronomer Charles Messier (1730 - 1817). It was not included in the first two editions (with 45 objects in 1774; 103 in 1781), but Messier soon thereafter added it by hand in his personal copy as a "very faint nebula". The recession velocity, about 1000 km/sec, was first measured by American astronomer Vesto M. Slipher at the Lowell Observatory in 1912; he was also the first to detect the galaxy's rotation. ESO Press Photo 07c/00 ESO Press Photo 07c/00 [Preview; JPEG: 400 x 307; 59k] [Normal; JPEG: 800 x 614; 308k] [Full-Res; JPEG: 2028 x 1556; 2.3Mb] PR Photo 07c/00 has been processed to show the numerous dust bands in the central plane of the Sombrero galaxy (see

  7. Shade tolerance plasticity in response to neutral vs green shade cues in Polygonum species of contrasting ecological breadth.

    PubMed

    Griffith, Timothy M; Sultan, Sonia E

    2005-04-01

    Here we examined species differences in perception and response to two distinct types of shade cue, reduced photosynthetically active radiation (PAR) with and without reduced red : far red ratio (R : FR), in Polygonum persicaria and Polygonum hydropiper, two closely related annuals of contrasting ecological breadth. We compared plasticity data for light-gathering traits from glasshouse experiments at equivalently reduced PAR under neutral shade (R : FR 1.03) and green shade (R : FR 0.702). Species shared the ability to distinguish between the two types of shade, as shown by the ability of each to respond differently to neutral vs green shade for one or more traits. However, the species' responses to these cues differed significantly. Polygonum persicaria expressed stronger shade-tolerance responses (increased leaf allocation and leaf area ratio) to reduced PAR alone than to green shade. By contrast, P. hydropiper expressed slightly less plasticity for these traits in neutral than in green shade. The pronounced plastic response of P. persicaria to neutral shade may contribute to the range of habitats this widespread species can occupy, which includes neutral-shade environments such as urban settings.

  8. Effect of shade on Arabica coffee berry disease development: Toward an agroforestry system to reduce disease impact.

    PubMed

    Mouen Bedimo, J A; Njiayouom, I; Bieysse, D; Ndoumbè Nkeng, M; Cilas, C; Nottéghem, J L

    2008-12-01

    Coffee berry disease (CBD), caused by Colletotrichum kahawae, is a major constraint for Arabica coffee cultivation in Africa. The disease is specific to green berries and can lead to 60% harvest losses. In Cameroon, mixed cropping systems of coffee with other crops, such as fruit trees, are very widespread agricultural practices. Fruit trees are commonly planted at random on coffee farms, providing a heterogeneous shading pattern for coffee trees growing underneath. Based on a recent study of CBD, it is known that those plants can reduce disease incidence. To assess the specific effect of shade, in situ and in vitro disease development was compared between coffee trees shaded artificially by a net and trees located in full sunlight. In the field, assessments confirmed a reduction in CBD on trees grown under shade compared with those grown in full sunlight. Artificial inoculations in the laboratory showed that shade did not have any effect on the intrinsic susceptibility of coffee berries to CBD. Coffee shading mainly acts on environmental parameters in limiting disease incidence. In addition to reducing yield losses, agroforestry system may also be helpful in reducing chemical control of the disease and in diversifying coffee growers' incomes.

  9. YUCCA auxin biosynthetic genes are required for Arabidopsis shade avoidance

    PubMed Central

    Müller-Moulé, Patricia; Nozue, Kazunari; Pytlak, Melissa L.; Palmer, Christine M.; Covington, Michael F.; Wallace, Andreah D.; Harmer, Stacey L.

    2016-01-01

    Plants respond to neighbor shade by increasing stem and petiole elongation. Shade, sensed by phytochrome photoreceptors, causes stabilization of PHYTOCHROME INTERACTING FACTOR proteins and subsequent induction of YUCCA auxin biosynthetic genes. To investigate the role of YUCCA genes in phytochrome-mediated elongation, we examined auxin signaling kinetics after an end-of-day far-red (EOD-FR) light treatment, and found that an auxin responsive reporter is rapidly induced within 2 hours of far-red exposure. YUCCA2, 5, 8, and 9 are all induced with similar kinetics suggesting that they could act redundantly to control shade-mediated elongation. To test this hypothesis we constructed a yucca2, 5, 8, 9 quadruple mutant and found that the hypocotyl and petiole EOD-FR and shade avoidance responses are completely disrupted. This work shows that YUCCA auxin biosynthetic genes are essential for detectable shade avoidance and that YUCCA genes are important for petiole shade avoidance. PMID:27761349

  10. Digital shaded-relief map of Venezuela

    USGS Publications Warehouse

    Garrity, Christopher P.; Hackley, Paul C.; Urbani, Franco

    2004-01-01

    The Digital Shaded-Relief Map of Venezuela is a composite of more than 20 tiles of 90 meter (3 arc second) pixel resolution elevation data, captured during the Shuttle Radar Topography Mission (SRTM) in February 2000. The SRTM, a joint project between the National Geospatial-Intelligence Agency (NGA) and the National Aeronautics and Space Administration (NASA), provides the most accurate and comprehensive international digital elevation dataset ever assembled. The 10-day flight mission aboard the U.S. Space Shuttle Endeavour obtained elevation data for about 80% of the world's landmass at 3-5 meter pixel resolution through the use of synthetic aperture radar (SAR) technology. SAR is desirable because it acquires data along continuous swaths, maintaining data consistency across large areas, independent of cloud cover. Swaths were captured at an altitude of 230 km, and are approximately 225 km wide with varying lengths. Rendering of the shaded-relief image required editing of the raw elevation data to remove numerous holes and anomalously high and low values inherent in the dataset. Customized ArcInfo Arc Macro Language (AML) scripts were written to interpolate areas of null values and generalize irregular elevation spikes and wells. Coastlines and major water bodies used as a clipping mask were extracted from 1:500,000-scale geologic maps of Venezuela (Bellizzia and others, 1976). The shaded-relief image was rendered with an illumination azimuth of 315? and an altitude of 65?. A vertical exaggeration of 2X was applied to the image to enhance land-surface features. Image post-processing techniques were accomplished using conventional desktop imaging software.

  11. Sinai Peninsula, Shaded Relief and Colored Height

    NASA Technical Reports Server (NTRS)

    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

  12. Bali, Shaded Relief and Colored Height

    NASA Technical Reports Server (NTRS)

    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

  13. Preference for C4 shade grasses increases hatchling performance in the butterfly, Bicyclus safitza.

    PubMed

    Nokelainen, Ossi; Ripley, Brad S; van Bergen, Erik; Osborne, Colin P; Brakefield, Paul M

    2016-08-01

    The Miocene radiation of C4 grasses under high-temperature and low ambient CO 2 levels occurred alongside the transformation of a largely forested landscape into savanna. This inevitably changed the host plant regime of herbivores, and the simultaneous diversification of many consumer lineages, including Bicyclus butterflies in Africa, suggests that the radiations of grasses and grazers may be evolutionary linked. We examined mechanisms for this plant-herbivore interaction with the grass-feeding Bicyclus safitza in South Africa. In a controlled environment, we tested oviposition preference and hatchling performance on local grasses with C3 or C4 photosynthetic pathways that grow either in open or shaded habitats. We predicted preference for C3 plants due to a hypothesized lower processing cost and higher palatability to herbivores. In contrast, we found that females preferred C4 shade grasses rather than either C4 grasses from open habitats or C3 grasses. The oviposition preference broadly followed hatchling performance, although hatchling survival was equally good on C4 or C3 shade grasses. This finding was explained by leaf toughness; shade grasses were softer than grasses from open habitats. Field monitoring revealed a preference of adults for shaded habitats, and stable isotope analysis of field-sampled individuals confirmed their preference for C4 grasses as host plants. Our findings suggest that plant-herbivore interactions can influence the direction of selection in a grass-feeding butterfly. Based on this work, we postulate future research to test whether these interactions more generally contribute to radiations in herbivorous insects via expansions into new, unexploited ecological niches. PMID:27551380

  14. Preference for C4 shade grasses increases hatchling performance in the butterfly, Bicyclus safitza.

    PubMed

    Nokelainen, Ossi; Ripley, Brad S; van Bergen, Erik; Osborne, Colin P; Brakefield, Paul M

    2016-08-01

    The Miocene radiation of C4 grasses under high-temperature and low ambient CO 2 levels occurred alongside the transformation of a largely forested landscape into savanna. This inevitably changed the host plant regime of herbivores, and the simultaneous diversification of many consumer lineages, including Bicyclus butterflies in Africa, suggests that the radiations of grasses and grazers may be evolutionary linked. We examined mechanisms for this plant-herbivore interaction with the grass-feeding Bicyclus safitza in South Africa. In a controlled environment, we tested oviposition preference and hatchling performance on local grasses with C3 or C4 photosynthetic pathways that grow either in open or shaded habitats. We predicted preference for C3 plants due to a hypothesized lower processing cost and higher palatability to herbivores. In contrast, we found that females preferred C4 shade grasses rather than either C4 grasses from open habitats or C3 grasses. The oviposition preference broadly followed hatchling performance, although hatchling survival was equally good on C4 or C3 shade grasses. This finding was explained by leaf toughness; shade grasses were softer than grasses from open habitats. Field monitoring revealed a preference of adults for shaded habitats, and stable isotope analysis of field-sampled individuals confirmed their preference for C4 grasses as host plants. Our findings suggest that plant-herbivore interactions can influence the direction of selection in a grass-feeding butterfly. Based on this work, we postulate future research to test whether these interactions more generally contribute to radiations in herbivorous insects via expansions into new, unexploited ecological niches.

  15. Influence of neighboring plants on shading stress resistance and recovery of eelgrass, Zostera marina L.

    PubMed

    Gustafsson, Camilla; Boström, Christoffer

    2013-01-01

    Stressful environments may enhance the occurrence of facilitative interspecific interactions between plants. In several regions, Zostera marina occurs in mixed assemblages. However, the potential effects of plant diversity on stress responses and stability properties of Z. marina are poorly understood. We investigated the resistance and recovery of Z. marina subjected to shading (1 mo) in a field experiment lasting 2.5 mo. We shaded Z. marina planted in mono- and polycultures (Potamogeton perfoliatus, P. pectinatus, P. filiformis) in a factorial design (Shading×Richness) at 2 m depth. We estimated the resistance and recovery of Z. marina by measuring four response variables. Polyculture Z. marina lost proportionally less biomass than monocultures, thus having a greater resistance to shading. In contrast, after a 1 mo recovery period, monocultures exhibited higher biomass gain, and a faster recovery than polycultures. Our results suggest that plant species richness enhances the resistance of Z. marina through facilitative mechanisms, while the faster recovery in monocultures is possibly due to interspecific competition. Our results highlight the need of a much better understanding of the effects of interspecific interactions on ecosystem processes in mixed seagrass meadows, and the preservation of diverse plant assemblages to maintain ecosystem functioning.

  16. Influence of Neighboring Plants on Shading Stress Resistance and Recovery of Eelgrass, Zostera marina L

    PubMed Central

    Gustafsson, Camilla; Boström, Christoffer

    2013-01-01

    Stressful environments may enhance the occurrence of facilitative interspecific interactions between plants. In several regions, Zostera marina occurs in mixed assemblages. However, the potential effects of plant diversity on stress responses and stability properties of Z. marina are poorly understood. We investigated the resistance and recovery of Z. marina subjected to shading (1 mo) in a field experiment lasting 2.5 mo. We shaded Z. marina planted in mono- and polycultures (Potamogeton perfoliatus, P. pectinatus, P. filiformis) in a factorial design (Shading×Richness) at 2 m depth. We estimated the resistance and recovery of Z. marina by measuring four response variables. Polyculture Z. marina lost proportionally less biomass than monocultures, thus having a greater resistance to shading. In contrast, after a 1 mo recovery period, monocultures exhibited higher biomass gain, and a faster recovery than polycultures. Our results suggest that plant species richness enhances the resistance of Z. marina through facilitative mechanisms, while the faster recovery in monocultures is possibly due to interspecific competition. Our results highlight the need of a much better understanding of the effects of interspecific interactions on ecosystem processes in mixed seagrass meadows, and the preservation of diverse plant assemblages to maintain ecosystem functioning. PMID:23717532

  17. Alpine Fault, New Zealand, SRTM Shaded Relief and Colored Height

    NASA Technical Reports Server (NTRS)

    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

  18. Vitamin D effective ultraviolet wavelengths due to scattering in shade.

    PubMed

    Turnbull, D J; Parisi, A V; Kimlin, M G

    2005-09-01

    Solar UVB radiation (280-320 nm) is an initiator of Vitamin D3 production in the human skin. While numerous studies have been conducted in relation to the biological impact of UV exposure in full sun, less research has investigated the irradiances in shade. The purpose of this study was to determine the levels of UV radiation in relation to Vitamin D3 induction with six commonly encountered shade environments for the larger solar zenith angles observed during autumn and winter. Spectral UV irradiance measurements were made under relatively clear sky conditions at a sub-tropical Southern Hemisphere site for six specific shade environments and solar zenith angle between 35 degrees and 60 degrees to investigate the biologically effective UV irradiances for pre-Vitamin D3 production. Data from this research indicates that pre-Vitamin D3 effective UV wavelengths in the shade were most significant for tree shade and a shade umbrella. Compared to that in full sun, pre-Vitamin D3 effective UV wavelengths were at levels of approximately 52 and 55%, respectively, beneath the shade umbrella and in tree shade. UVB irradiance levels in the shade of a northern facing covered veranda and in a car with windows closed were significantly less than those beneath the shade umbrella, with levels of approximately 11 and 0%, respectively, of those in full sun. Shade is important as a UV minimisation strategy; however, it may also play an important role in providing the human body with adequate levels of UVB radiation for pre-Vitamin D3 production without experiencing the relatively higher levels of UVA irradiances present in full sun.

  19. Influence of shading on container-grown flowering dogwoods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  20. Optimal integration of shading and binocular disparity for depth perception.

    PubMed

    Lovell, Paul G; Bloj, Marina; Harris, Julie M

    2012-01-01

    We explore the relative utility of shape from shading and binocular disparity for depth perception. Ray-traced images either featured a smooth surface illuminated from above (shading-only) or were defined by small dots (disparity-only). Observers judged which of a pair of smoothly curved convex objects had most depth. The shading cue was around half as reliable as the rich disparity information for depth discrimination. Shading- and disparity-defined cues where combined by placing dots in the stimulus image, superimposed upon the shaded surface, resulting in veridical shading and binocular disparity. Independently varying the depth delivered by each channel allowed creation of conflicting disparity-defined and shading-defined depth. We manipulated the reliability of the disparity information by adding disparity noise. As noise levels in the disparity channel were increased, perceived depths and variances shifted toward those of the now more reliable shading cue. Several different models of cue combination were applied to the data. Perceived depths and variances were well predicted by a classic maximum likelihood estimator (MLE) model of cue integration, for all but one observer. We discuss the extent to which MLE is the most parsimonious model to account for observer performance.

  1. 21 CFR 872.3690 - Tooth shade resin material.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Tooth shade resin material. 872.3690 Section 872.3690 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Prosthetic Devices § 872.3690 Tooth shade resin material....

  2. Shaded Relief of Rio Sao Francisco, Brazil

    NASA Technical Reports Server (NTRS)

    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

  3. Shaded relief of Bahia State, Brazil

    NASA Technical Reports Server (NTRS)

    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

  4. Ireland, Shaded Relief and Colored Height

    NASA Technical Reports Server (NTRS)

    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

  5. World Globes, Shaded Relief and Colored Height

    NASA Technical Reports Server (NTRS)

    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

  6. Sapling leaf trait responses to light, tree height and soil nutrients for three conifer species of contrasting shade tolerance.

    PubMed

    Lilles, Erica B; Astrup, Rasmus; Lefrançois, Marie-Lou; David Coates, K

    2014-12-01

    We developed models to describe the responses of four commonly examined leaf traits (mass per area, weight, area and nitrogen (N) concentration) to gradients of light, soil nutrients and tree height in three conifer species of contrasting shade tolerance. Our observational dataset from the sub-boreal spruce forests of British Columbia included subalpine fir (Abies lasioscarpa [Hook.] Nutt; high shade tolerance), interior spruce (Picea glauca × Picea engelmannii [Moench] Voss; intermediate shade tolerance) and lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia; low shade tolerance) saplings from 0.18 to 4.87 m tall, in 8-98% of total incident light, from field sites with <17.6 kg ha(-1) to >46.8 kg ha(-1) total dissolved N. Leaf weights and areas showed strong positive responses to light and height, but little or no response to soil nutrients. Parameter estimates indicated that the shape of leaf weight and area responses to light corresponded with shade tolerance ranking for the three species; pine had the most linear response whereas spruce and fir had asymptotic responses. Leaf N concentration responded positively to soil nutrients, negatively to light and idiosyncratically to height. The negative effect of light was only apparent on sites of high soil nutrient availability, and parameter estimates for the shape of the negative response also corresponded to shade tolerance ranking (apine = -0.79, aspruce = -0.15, afir = -0.07). Of the traits we measured, leaf mass per area showed the least response to light, soil nutrient and height gradients. Although it is a common practice in comparisons across many species, characterizing these conifers by mean values of their leaf traits would miss important intraspecific variation across environmental and size gradients. In these forests, parameter estimates representing the intraspecific variability of leaf trait responses can be used to understand relative shade tolerances. PMID

  7. Sapling leaf trait responses to light, tree height and soil nutrients for three conifer species of contrasting shade tolerance.

    PubMed

    Lilles, Erica B; Astrup, Rasmus; Lefrançois, Marie-Lou; David Coates, K

    2014-12-01

    We developed models to describe the responses of four commonly examined leaf traits (mass per area, weight, area and nitrogen (N) concentration) to gradients of light, soil nutrients and tree height in three conifer species of contrasting shade tolerance. Our observational dataset from the sub-boreal spruce forests of British Columbia included subalpine fir (Abies lasioscarpa [Hook.] Nutt; high shade tolerance), interior spruce (Picea glauca × Picea engelmannii [Moench] Voss; intermediate shade tolerance) and lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia; low shade tolerance) saplings from 0.18 to 4.87 m tall, in 8-98% of total incident light, from field sites with <17.6 kg ha(-1) to >46.8 kg ha(-1) total dissolved N. Leaf weights and areas showed strong positive responses to light and height, but little or no response to soil nutrients. Parameter estimates indicated that the shape of leaf weight and area responses to light corresponded with shade tolerance ranking for the three species; pine had the most linear response whereas spruce and fir had asymptotic responses. Leaf N concentration responded positively to soil nutrients, negatively to light and idiosyncratically to height. The negative effect of light was only apparent on sites of high soil nutrient availability, and parameter estimates for the shape of the negative response also corresponded to shade tolerance ranking (apine = -0.79, aspruce = -0.15, afir = -0.07). Of the traits we measured, leaf mass per area showed the least response to light, soil nutrient and height gradients. Although it is a common practice in comparisons across many species, characterizing these conifers by mean values of their leaf traits would miss important intraspecific variation across environmental and size gradients. In these forests, parameter estimates representing the intraspecific variability of leaf trait responses can be used to understand relative shade tolerances.

  8. Benefit of Shading by Nurse Plant Does Not Change along a Stress Gradient in a Coastal Dune

    PubMed Central

    Castanho, Camila de Toledo; Prado, Paulo Inácio

    2014-01-01

    The proximity of adult neighbors often increases the performance of woody seedlings under harsh environmental conditions but this nurse plant effect becomes less intense when abiotic stress is alleviated, as predicted by the stress gradient hypothesis (SGH). Although some studies have tested how the net nurse effect is changed by stress, few studies have tested how the mechanism that drives the facilitative effect of nurse responds to changes in stress. We conducted field experiments in a subtropical coastal dune to test if shading drives the known nurse effect of adults of the tree Guapira opposita on seedling performance of another tree species, Ternstroemia brasiliensis. We transplanted T. brasiliensis seedlings to three neighbor environments: under a G. opposita crown, under artificial shade and without neighbor as a control. Furthermore, assuming that proximity to the seashore correlates with stress intensity, we tested if the potential shade-driven facilitation became less intense as stress decreased. Regardless of the proximity to the seashore, after a year, the survival of T. brasiliensis seedlings was twice as high when the seedlings were under G. opposita or under artificial shade compared to the control, indicating that the nurse effect is driven by shade and that this facilitation mechanism is constant along the stress gradient. However, G. opposita and artificial shade had a negative effect on seedlings growth. Overall, our results showed that the facilitation mechanism behind the nurse effect did not wane as the stress was reduced. Furthermore, in spite of the potential costs in terms of biomass production, our study highlights the potential of nurse plants and artificial shade as techniques to improve the survival of transplanted seedlings used in the restoration of degraded shrubland coastal dunes. PMID:25127399

  9. Does shade improve light interception efficiency? A comparison among seedlings from shade-tolerant and -intolerant temperate deciduous tree species.

    PubMed

    Delagrange, Sylvain; Montpied, Pierre; Dreyer, Erwin; Messier, Christian; Sinoquet, Hervé

    2006-01-01

    Here, we tested two hypotheses: shading increases light interception efficiency (LIE) of broadleaved tree seedlings, and shade-tolerant species exhibit larger LIEs than do shade-intolerant ones. The impact of seedling size was taken into account to detect potential size-independent effects on LIE. LIE was defined as the ratio of mean light intercepted by leaves to light intercepted by a horizontal surface of equal area. Seedlings from five species differing in shade tolerance (Acer saccharum, Betula alleghaniensis, A. pseudoplatanus, B. pendula, Fagus sylvatica) were grown under neutral shading nets providing 36, 16 and 4% of external irradiance. Seedlings (1- and 2-year-old) were three-dimensionally digitized, allowing calculation of LIE. Shading induced dramatic reduction in total leaf area, which was lowest in shade-tolerant species in all irradiance regimes. Irradiance reduced LIE through increasing leaf overlap with increasing leaf area. There was very little evidence of significant size-independent plasticity of LIE. No relationship was found between the known shade tolerance of species and LIE at equivalent size and irradiance.

  10. Effects of shade on physiological changes, oxidative stress, and total antioxidant power in Thai Brahman cattle

    NASA Astrophysics Data System (ADS)

    Aengwanich, Worapol; Kongbuntad, Watee; Boonsorn, Thongchai

    2011-09-01

    The purpose of this study was to assess the effects of artificial shade, tree shade, and no shade on physiological changes, oxidative stress, and total antioxidant power in Thai Brahman cattle. Twenty-one cattle were divided into three groups: cattle maintained under artificial shade, under tree shade, and without shade. On days 1, 7, 14, 21, and 28 of the experimental period, after the cattle were set in individual stalls for 2 h, physiological changes, thiobarbituric acid reactive substances (TBARS), and total antioxidant power were investigated. The results revealed that the respiratory rate, heart rate, sweat rate and the neutrophil/lymphocyte ratio of the no-shade cattle were significantly higher than those of cattle maintained under artificial shade and tree shade ( P < 0.05). During the early period of heat exposure, the total antioxidant power of the no-shade cattle was lower than those of cattle maintained under artificial shade and tree shade, but the total antioxidant power of cattle maintained under artificial shade and tree shade were not different ( P > 0.05). However, rectal temperature and packed cell volume of the cattle in all groups did not differ ( P > 0.05). These results showed that artificial shade and tree shade can protect cattle from sunlight compared to no shade, and that the effectiveness of tree shade for sunlight protection is at an intermediate level.

  11. Olduvai Gorge, Shaded Relief and Colored Height

    NASA Technical Reports Server (NTRS)

    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

  12. Metameric effect between natural teeth and the shade tabs of a shade guide.

    PubMed

    Corcodel, Nicoleta; Helling, Stephan; Rammelsberg, Peter; Hassel, Alexander J

    2010-06-01

    The objective of this study was to evaluate metameric effects, that is, the dependence of the colours of teeth and shade tabs on the illuminant used. The colours of 49 teeth of 37 participants and of the corresponding shade tabs of the 3D-Master (VITA Zahnfabrik; colour match DeltaE(ab)< 2) were measured using an intra-oral spectrophotometer (VITA Easyshade). Spectral reflectance data (from 400 to 700 nm) were recorded. Commission Internationale de l'Eclairage (CIE) L*a*b* values were calculated for D65 (reference daylight), A (incandescent light), and TL84 (store/office light) as reference illuminants. A modified metamerism index (Mod-M) and hue-angle ratios were calculated to express differences between tooth and tab colour relative to the difference observed under D65 illumination. The Mod-M for teeth and tabs was greater than unity (indicating a greater colour difference relative to D65) by 57.1% for A and by 49.3% for TL84. Hue-angle ratios of teeth and tabs using the test illuminants were different from those obtained using the standard illuminant D65. If teeth and shade tab matching is conducted using daylight illumination, the colour difference may not be the same under other lighting conditions, leading to perceptible, or even unacceptable, colour differences under these conditions.

  13. Photovoltaic Shading Testbed for Module-Level Power Electronics

    SciTech Connect

    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.

  14. Chlorophyll fluorescence kinetics, photosynthetic activity, and pigment composition of blue-shade and half-shade leaves as compared to sun and shade leaves of different trees.

    PubMed

    Lichtenthaler, Hartmut K; Babani, Fatbardha; Navrátil, Martin; Buschmann, Claus

    2013-11-01

    The chlorophyll (Chl) fluorescence induction kinetics, net photosynthetic CO2 fixation rates P N, and composition of photosynthetic pigments of differently light exposed leaves of several trees were comparatively measured to determine the differences in photosynthetic activity and pigment adaptation of leaves. The functional measurements were carried out with sun, half-shade and shade leaves of seven different trees species. These were: Acer platanoides L., Ginkgo biloba L., Fagus sylvatica L., Platanus x acerifolia Willd., Populus nigra L., Quercus robur L., Tilia cordata Mill. In three cases (beech, ginkgo, and oak), we compared the Chl fluorescence kinetics and photosynthetic rates of blue-shade leaves of the north tree crown receiving only blue sky light but no direct sunlight with that of sun leaves. In these cases, we also determined in detail the pigment composition of all four leaf types. In addition, we determined the quantum irradiance and spectral irradiance of direct sunlight, blue skylight as well as the irradiance in half shade and full shade. The results indicate that sun leaves possess significantly higher mean values for the net CO2 fixation rates P N (7.8-10.7 μmol CO2 m(-2) s(-1) leaf area) and the Chl fluorescence ratio R Fd (3.85-4.46) as compared to shade leaves (mean P N of 2.6-3.8 μmol CO2 m(-2) s(-1) leaf area.; mean R Fd of 1.94-2.56). Sun leaves also exhibit higher mean values for the pigment ratio Chl a/b (3.14-3.31) and considerably lower values for the weight ratio total chlorophylls to total carotenoids, (a + b)/(x + c), (4.07-4.25) as compared to shade leaves (Chl a/b 2.62-2.72) and (a + b)/(x + c) of 5.18-5.54. Blue-shade and half-shade leaves have an intermediate position between sun and shade leaves in all investigated parameters including the ratio F v/F o (maximum quantum yield of PS2 photochemistry) and are significantly different from sun and shade leaves but could not be differentiated from each other. The

  15. A Custom Made Intrinsic Silicone Shade Guide for Indian Population

    PubMed Central

    Behanam, Mohammed; Ahila, S.C.; Jei, J. Brintha

    2016-01-01

    Introduction Replication of natural skin colour in maxillofacial prosthesis has been traditionally done using trial and error method, as concrete shade guides are unavailable till date. Hence a novel custom made intrinsic silicone shade guide has been attempted for Indian population. Aim Reconstruction of maxillofacial defects is challenging, as achieving an aesthetic result is not always easy. A concoction of a novel intrinsic silicone shade guide was contemplated for the study and its reproducibility in clinical practice was analysed. Materials and Methods Medical grade room temperature vulcanising silicone was used for the fabrication of shade tabs. The shade guide consisted of three main groups I, II and III which were divided based upon the hues yellow, red and blue respectively. Five distinct intrinsic pigments were added in definite proportions to subdivide each group of different values from lighter to darker shades. A total number of 15 circular shade tabs comprised the guide. To validate the usage of the guide, visual assessment of colour matching was done by four investigators to investigate the consent of perfect colour correspondence. Data was statistically analysed using kappa coefficients. Results The kappa values were found to be 0.47 to 0.78 for yellow based group I, 0.13 to 0.65 for red based group II, and 0.07 to 0.36 for blue based group III. This revealed that the shade tabs of yellow and red based hues matched well and showed a statistically good colour matching. Conclusion This intrinsic silicone shade guide can be effectively utilised for fabrication of maxillofacial prosthesis with silicone in Indian population. A transparent colour formula with definite proportioning of intrinsic pigments is provided for obtaining an aesthetic match to skin tone. PMID:27190946

  16. France, Shaded Relief and Colored Height

    NASA Technical Reports Server (NTRS)

    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

  17. Guiana Highlands, Shaded Relief and Colored Height

    NASA Technical Reports Server (NTRS)

    2003-01-01

    inspiration for Arthur Conan 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

  18. Australia, Shaded Relief and Colored Height

    NASA Technical Reports Server (NTRS)

    2004-01-01

    : 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: 45 to 10 degrees South latitude, 112 to 155 degrees East longitude Orientation: North toward the top, Mercator projection Image Data: shaded and colored SRTM elevation model Date Acquired: February 2000

  19. Shaded relief, color as height Patagonia, Argentina

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This topographic image of Patagonia, Argentina shows a spectacular landscape formed by volcanoes, rivers, and wind. The area is located just east of the narrow range of the Andes Mountains, about 100 kilometers (62 miles) east of the border with Chile. Interesting features include basalt-capped mesas with sinkholes (lower center), arcuate ridges of windblown beach sands downwind from a salty desert lake (upper center), young volcanic cones(right), and at least one case of what geologists call 'inverted relief'. This happens when lava flows down a valley in soft material and then the soft material is eroded away leaving the former valley as a ridge of lava. These ridges can be seen on the slopes of the volcano in the upper right. Geologists will use SRTM topographic data to study the interaction of volcanic, climatic and erosional processes.

    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 1100 meters(3600 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

  20. Photoreceptor signaling networks in plant responses to shade.

    PubMed

    Casal, Jorge J

    2013-01-01

    The dynamic light environment of vegetation canopies is perceived by phytochromes, cryptochromes, phototropins, and UV RESISTANCE LOCUS 8 (UVR8). These receptors control avoidance responses to preclude exposure to limiting or excessive light and acclimation responses to cope with conditions that cannot be avoided. The low red/far-red ratios of shade light reduce phytochrome B activity, which allows PHYTOCHROME INTERACTING FACTORS (PIFs) to directly activate the transcription of auxin-synthesis genes, leading to shade-avoidance responses. Direct PIF interaction with DELLA proteins links gibberellin and brassinosteroid signaling to shade avoidance. Shade avoidance also requires CONSTITUTIVE PHOTOMORPHOGENESIS 1 (COP1), a target of cryptochromes, phytochromes, and UVR8. Multiple regulatory loops and the input of the circadian clock create a complex network able to respond even to subtle threats of competition with neighbors while still compensating for major environmental fluctuations such as the day-night cycles.

  1. Dynamic Shade and Irradiance Simulation of Aquatic Landscapes and Watersheds

    EPA Science Inventory

    Penumbra is a landscape shade and irradiance simulation model that simulates how solar energy spatially and temporally interacts within dynamic ecosystems such as riparian zones, forests, and other terrain that cast topological shadows. Direct and indirect solar energy accumulate...

  2. DETAIL OF CORNICE MOULDING WITH RAM'S HEAD MOTIF. EIGHT SHADES ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    DETAIL OF CORNICE MOULDING WITH RAM'S HEAD MOTIF. EIGHT SHADES OF GOLD LEAF AND BURNISHED GOLD LEAF WERE USED FOR THE INTERIOR FINISHES. - Anaconda Historic District, Washoe Theater, 305 Main Street, Anaconda, Deer Lodge County, MT

  3. Determination of the Solar Ultraviolet Transmission in Tree Shade.

    ERIC Educational Resources Information Center

    Parisi, Alfio V.; Kimlin, Michael G.

    1999-01-01

    Presents an activity in which the amount of solar ultraviolet radiation in tree shade is measured at different times of the day and compared with changes in illumination levels and temperature. (Author/WRM)

  4. Evaluation of the Aurora Application Shade Measurement Accuracy

    SciTech Connect

    2015-12-01

    Aurora is an integrated, Web-based application that helps solar installers perform sales, engineering design, and financial analysis. One of Aurora's key features is its high-resolution remote shading analysis.

  5. Shade images of forested areas obtained from Landsat MSS data

    NASA Technical Reports Server (NTRS)

    Shimabukuro, Yosio Edemir; Smith, James A.

    1989-01-01

    The objective of this report is to generate a shade (shadow) image of forested areas from Landsat MSS data by implementing a linear mixing model, where shadow is considered as one of the primary components in a pixel. The shade images are related to the observed variation in forest structure; i.e., the proportion of inferred shadow in a pixel is related to different forest ages, forest types, and tree crown cover. The constrained least-squares method is used to generate shade images for forest of eucalyptus and vegetation of 'cerrado' over the Itapeva study area in Brazil. The resulted shade images may explain the difference on ages for forest of eucalyptus and the difference on tree crown cover for vegetation of cerrado.

  6. Why are evergreen leaves so contrary about shade?

    PubMed

    Lusk, Christopher H; Reich, Peter B; Montgomery, Rebecca A; Ackerly, David D; Cavender-Bares, Jeannine

    2008-06-01

    Leaf mass per area (LMA) is one of the most widely measured of all plant functional traits. In deciduous forests, there is similarity between plastic and evolutionary responses of LMA to light gradients. In evergreens, however, LMA is lower in shaded than sunlit individuals of the same species, whereas shade-tolerant evergreens have higher LMA than light-demanders grown under the same conditions. We suggest that this pattern of 'counter-gradient variation' results from some combination of (i) close evolutionary coordination of LMA with leaf lifespan, (ii) selection for different leaf constitutions (relative investment in cell walls versus cell contents) in sun and shade environments and/or (iii) constraints on plasticity as a result of genetic correlations between phenotypes expressed in sun and shade.

  7. [Photosynthetic characteristics of Gynostemma pentaphyllum under shade].

    PubMed

    Huang, Chenglin; Wu, Zemin; Yao, Yongkang; Xu, Xiaoniu

    2004-11-01

    The study showed that under summer shade condition, the diurnal variation of net photosynthetic rate of Gynostemma pentaphyllum presented nontypical double apex, the first apex being 13.8 micromol CO2 x m(-2) x s(-1) at 11:00, and the diurnal net photosynthetic rate was about 176.97 micromol CO2 x m(-2), 3.1 times of that under full sunlight. There was a positive correlation between net photosynthetic rate and photon flux density (PFD), and relative humidity had a small effect on net photosynthetic rate. Under full sunlight, the typical "midday depression" of photosynthesis was observed, and the diurnal variation of net photosynthetic rate presented double apex, with the first apex being 3.0 micromol CO2 x m(-2) x s(-1) at 10:00 and the second being 1.25 micromol CO2 x m(-2) x s(-1) at 14:00. There was a positive correlation between net photosynthetic rate and relative humidity, and the latter had a strong effect on net photosynthetic rate. When PFD was higher than 700 micromol CO2 x m(-2) x s(-1), it had a negative correlation with net photosynthetic rate. Stoma conductance was the main factor affecting the transpiration rate of Gynostemma pentaphyllum. Therefore, Gynostemma pentaphyllum was a typical sciophytic plant, and light factor should be considered firstly in its cultivation. PMID:15707321

  8. Shaded-Color Picture Generation of Computer-Defined Arbitrary Shapes

    NASA Technical Reports Server (NTRS)

    Cozzolongo, J. V.; Hermstad, D. L.; Mccoy, D. S.; Clark, J.

    1986-01-01

    SHADE computer program generates realistic color-shaded pictures from computer-defined arbitrary shapes. Objects defined for computer representation displayed as smooth, color-shaded surfaces, including varying degrees of transparency. Results also used for presentation of computational results. By performing color mapping, SHADE colors model surface to display analysis results as pressures, stresses, and temperatures. NASA has used SHADE extensively in sign and analysis of high-performance aircraft. Industry should find applications for SHADE in computer-aided design and computer-aided manufacturing. SHADE written in VAX FORTRAN and MACRO Assembler for either interactive or batch execution.

  9. Microhardness of different resin cement shades inside the root canal

    PubMed Central

    Vignolo, Valeria; Fuentes, Maria V.; Garrido, Miguel A.; Rodríguez, Jesús

    2012-01-01

    Objectives: To compare microhardness along the root canal post space of two resin cements in different shades and a dual-cure resin core material. Study Design: Root canals of 21 bovine incisors were prepared for post space. Translucent posts (X•Post, Dentsply DeTrey) were luted using one the following resin luting agent: Calibra (Dentsply DeTrey) in Translucent, Medium and Opaque shades, RelyX Unicem (3M ESPE) in Translucent, A2 and A3 shades and the dual-cure resin core material Core•X flow. All materials were applied according to manufacturers’ instructions and were all photopolymerized (Bluephase LED unit, Ivoclar Vivadent, 40s). After 24 hours, roots were transversally cut into 9 slices 1 mm thick from the coronal to apical extremes, three corresponding to each root third. Then, VHNs were recorded (100 gf, 30 s) on the resin luting materials along the adhesive interface in all sections. Data were analyzed by two-way ANOVA and SNK tests (α=0.05). Results: A significant influence on microhardness of resin luting material in their respective shades (p<0.001), root third (p<0.001) and interactions between them was detected (p<0.001). RelyX Unicem cement showed the highest microhardness values and Calibra the lowest, regardless of the shade selected. All resin luting materials tested exhibited a significantly higher microhardness in the cervical third. Conclusions: Microhardness of resin luting agents tested inside the canal is dependent on material brand and resin cement shade seems to be a less relevant factor. Microhardness decreased along the root canal, regardless of the shade selected. Key words:Cement shade, degree of conversion, dual-cured resin cements, fiber posts, microhardness, root thirds. PMID:22322514

  10. Transcriptome response of cassava leaves under natural shade

    PubMed Central

    Ding, Zehong; Zhang, Yang; Xiao, Yi; Liu, Fangfang; Wang, Minghui; Zhu, Xinguang; Liu, Peng; Sun, Qi; Wang, Wenquan; Peng, Ming; Brutnell, Tom; Li, Pinghua

    2016-01-01

    Cassava is an important staple crop in tropical and sub-tropical areas. As a common farming practice, cassava is usually cultivated intercropping with other crops and subjected to various degrees of shading, which causes reduced productivity. Herein, a comparative transcriptomic analysis was performed on a series of developmental cassava leaves under both full sunlight and natural shade conditions. Gene expression profiles of these two conditions exhibited similar developmental transitions, e.g. genes related to cell wall and basic cellular metabolism were highly expressed in immature leaves, genes involved in lipid metabolism and tetrapyrrole synthesis were highly expressed during the transition stages, and genes related to photosynthesis and carbohydrates metabolism were highly expressed in mature leaves. Compared with the control, shade significantly induced the expression of genes involved in light reaction of photosynthesis, light signaling and DNA synthesis/chromatin structure; however, the genes related to anthocyanins biosynthesis, heat shock, calvin cycle, glycolysis, TCA cycle, mitochondrial electron transport, and starch and sucrose metabolisms were dramatically depressed. Moreover, the shade also influenced the expression of hormone-related genes and transcriptional factors. The findings would improve our understanding of molecular mechanisms of shade response, and shed light on pathways associated with shade-avoidance syndrome for cassava improvement. PMID:27539510

  11. Infants' discrimination of shapes from shading and cast shadows.

    PubMed

    Sato, Kazuki; Kanazawa, So; Yamaguchi, Masami K

    2016-07-01

    Shadows are powerful cues in the perception of shapes. We can perceive shading and cast shadow implicitly. We investigated infants' ability to detect a single discrepant figure that was depicted by shading or cast shadow and examined the influence of the contrast polarity of shadows on this process. In Experiment 1, we manipulated the blur direction of a shadow to create stimuli that appeared either to be partially shaded or to cast a shadow and then used a preference to test whether this difference would allow 5- to 8-month-old infants to discriminate the figures that adults were able to perceive as different shapes. Only 7- to-8-month-old infants could differentiate one shading figure from cast shadow figures, and vice versa. In Experiment 2, we reversed the contrast polarity of the figure (dark object with a light shadow) and tested whether discrimination was affected. As has been found with adults, infants exposed to this condition were unable to discriminate the contrast-reversed shading and cast shadow figures. Our results suggested that an age of around 7 months is important for development of the ability to perceive shape differences from shading and cast shadows.

  12. Shade Effects on the Dispersal of Airborne Hemileia vastatrix Uredospores.

    PubMed

    Boudrot, Audrey; Pico, Jimmy; Merle, Isabelle; Granados, Eduardo; Vílchez, Sergio; Tixier, Philippe; Filho, Elías de Melo Virginio; Casanoves, Fernando; Tapia, Ana; Allinne, Clémentine; Rice, Robert A; Avelino, Jacques

    2016-06-01

    Hemileia vastatrix caused a severe epidemic in Central America in 2012-13. The gradual development of that epidemic on nearly a continental scale suggests that dispersal at different scales played a significant role. Shade has been proposed as a way of reducing uredospore dispersal. The effect of shade (two strata: Erythrina poeppigiana below and Chloroleucon eurycyclum above) and full sun on H. vastatrix dispersal was studied with Burkard traps in relation to meteorological records. Annual and daily patterns of dispersal were observed, with peaks of uredospore capture obtained during wet seasons and in the early afternoon. A maximum of 464 uredospores in 1 day (in 14.4 m(3) of air) was recorded in October 2014. Interactions between shade/full sun and meteorological conditions were found. Rainfall, possibly intercepted by tree cover and redistributed by raindrops of higher kinetic energy, was the main driver of uredospore dispersal under shade. Wind gusts reversed this effect, probably by inhibiting water accumulation on leaves. Wind gusts also promoted dispersal under dry conditions in full sun, whereas they had no effect under shaded conditions, probably because the canopy blocked the wind. Our results indicate the importance of managing shade cover differentially in rainy versus dry periods to control the dispersal of airborne H. vastatrix uredospores.

  13. Shade Effects on the Dispersal of Airborne Hemileia vastatrix Uredospores.

    PubMed

    Boudrot, Audrey; Pico, Jimmy; Merle, Isabelle; Granados, Eduardo; Vílchez, Sergio; Tixier, Philippe; Filho, Elías de Melo Virginio; Casanoves, Fernando; Tapia, Ana; Allinne, Clémentine; Rice, Robert A; Avelino, Jacques

    2016-06-01

    Hemileia vastatrix caused a severe epidemic in Central America in 2012-13. The gradual development of that epidemic on nearly a continental scale suggests that dispersal at different scales played a significant role. Shade has been proposed as a way of reducing uredospore dispersal. The effect of shade (two strata: Erythrina poeppigiana below and Chloroleucon eurycyclum above) and full sun on H. vastatrix dispersal was studied with Burkard traps in relation to meteorological records. Annual and daily patterns of dispersal were observed, with peaks of uredospore capture obtained during wet seasons and in the early afternoon. A maximum of 464 uredospores in 1 day (in 14.4 m(3) of air) was recorded in October 2014. Interactions between shade/full sun and meteorological conditions were found. Rainfall, possibly intercepted by tree cover and redistributed by raindrops of higher kinetic energy, was the main driver of uredospore dispersal under shade. Wind gusts reversed this effect, probably by inhibiting water accumulation on leaves. Wind gusts also promoted dispersal under dry conditions in full sun, whereas they had no effect under shaded conditions, probably because the canopy blocked the wind. Our results indicate the importance of managing shade cover differentially in rainy versus dry periods to control the dispersal of airborne H. vastatrix uredospores. PMID:26828230

  14. Infants' discrimination of shapes from shading and cast shadows.

    PubMed

    Sato, Kazuki; Kanazawa, So; Yamaguchi, Masami K

    2016-07-01

    Shadows are powerful cues in the perception of shapes. We can perceive shading and cast shadow implicitly. We investigated infants' ability to detect a single discrepant figure that was depicted by shading or cast shadow and examined the influence of the contrast polarity of shadows on this process. In Experiment 1, we manipulated the blur direction of a shadow to create stimuli that appeared either to be partially shaded or to cast a shadow and then used a preference to test whether this difference would allow 5- to 8-month-old infants to discriminate the figures that adults were able to perceive as different shapes. Only 7- to-8-month-old infants could differentiate one shading figure from cast shadow figures, and vice versa. In Experiment 2, we reversed the contrast polarity of the figure (dark object with a light shadow) and tested whether discrimination was affected. As has been found with adults, infants exposed to this condition were unable to discriminate the contrast-reversed shading and cast shadow figures. Our results suggested that an age of around 7 months is important for development of the ability to perceive shape differences from shading and cast shadows. PMID:27150615

  15. Transcriptome response of cassava leaves under natural shade.

    PubMed

    Ding, Zehong; Zhang, Yang; Xiao, Yi; Liu, Fangfang; Wang, Minghui; Zhu, Xinguang; Liu, Peng; Sun, Qi; Wang, Wenquan; Peng, Ming; Brutnell, Tom; Li, Pinghua

    2016-08-19

    Cassava is an important staple crop in tropical and sub-tropical areas. As a common farming practice, cassava is usually cultivated intercropping with other crops and subjected to various degrees of shading, which causes reduced productivity. Herein, a comparative transcriptomic analysis was performed on a series of developmental cassava leaves under both full sunlight and natural shade conditions. Gene expression profiles of these two conditions exhibited similar developmental transitions, e.g. genes related to cell wall and basic cellular metabolism were highly expressed in immature leaves, genes involved in lipid metabolism and tetrapyrrole synthesis were highly expressed during the transition stages, and genes related to photosynthesis and carbohydrates metabolism were highly expressed in mature leaves. Compared with the control, shade significantly induced the expression of genes involved in light reaction of photosynthesis, light signaling and DNA synthesis/chromatin structure; however, the genes related to anthocyanins biosynthesis, heat shock, calvin cycle, glycolysis, TCA cycle, mitochondrial electron transport, and starch and sucrose metabolisms were dramatically depressed. Moreover, the shade also influenced the expression of hormone-related genes and transcriptional factors. The findings would improve our understanding of molecular mechanisms of shade response, and shed light on pathways associated with shade-avoidance syndrome for cassava improvement.

  16. Characterization of shade avoidance responses in Lotus japonicus.

    PubMed

    Ueoka-Nakanishi, Hanayo; Hori, Nanako; Ishida, Kai; Ono, Natsuko; Yamashino, Takafumi; Nakamichi, Norihito; Mizuno, Takeshi

    2011-01-01

    Sessile plants must continuously adjust their growth and development to optimize photosynthetic activity under ever-fluctuating light conditions. Among such light responses in plants, one of the best-characterized events is the so-called shade avoidance, for which a low ratio of the red (R):far-red (FR) light intensities is the most prominent stimulus. Such shade avoidance responses enable plants to overtop their neighbors, thereby enhancing fitness and competitiveness in their natural habitat. Considerable progress has been achieved during the last decade in understanding the molecular mechanisms underlying the shade avoidance responses in the model rosette plant, Arabidopsis thaliana. We characterize here the fundamental aspects of the shade avoidance responses in the model legume, Lotus japonicus, based on the fact that its phyllotaxis (or morphological architecture) is quite different from that of A. thaliana. It was found that L. japonicus displays the characteristic shade avoidance syndrome (SAS) under defined laboratory conditions (a low R:FR ratio, low light intensity, and low blue light intensity) that mimic the natural canopy. In particular, the outgrowth of axillary buds (i.e., both aerial and cotyledonary shoot branching) was severely inhibited in L. japonicus grown in the shade. These results are discussed with special emphasis on the unique aspects of SAS observed with this legume.

  17. Transcriptome response of cassava leaves under natural shade.

    PubMed

    Ding, Zehong; Zhang, Yang; Xiao, Yi; Liu, Fangfang; Wang, Minghui; Zhu, Xinguang; Liu, Peng; Sun, Qi; Wang, Wenquan; Peng, Ming; Brutnell, Tom; Li, Pinghua

    2016-01-01

    Cassava is an important staple crop in tropical and sub-tropical areas. As a common farming practice, cassava is usually cultivated intercropping with other crops and subjected to various degrees of shading, which causes reduced productivity. Herein, a comparative transcriptomic analysis was performed on a series of developmental cassava leaves under both full sunlight and natural shade conditions. Gene expression profiles of these two conditions exhibited similar developmental transitions, e.g. genes related to cell wall and basic cellular metabolism were highly expressed in immature leaves, genes involved in lipid metabolism and tetrapyrrole synthesis were highly expressed during the transition stages, and genes related to photosynthesis and carbohydrates metabolism were highly expressed in mature leaves. Compared with the control, shade significantly induced the expression of genes involved in light reaction of photosynthesis, light signaling and DNA synthesis/chromatin structure; however, the genes related to anthocyanins biosynthesis, heat shock, calvin cycle, glycolysis, TCA cycle, mitochondrial electron transport, and starch and sucrose metabolisms were dramatically depressed. Moreover, the shade also influenced the expression of hormone-related genes and transcriptional factors. The findings would improve our understanding of molecular mechanisms of shade response, and shed light on pathways associated with shade-avoidance syndrome for cassava improvement. PMID:27539510

  18. SRTM Colored and Shaded Topography: Haro and Kas Hills, India

    NASA Technical Reports Server (NTRS)

    2001-01-01

    On January 26, 2001, the Kachchh region in western India suffered the most deadly earthquake in India's history. This shaded topography view of landforms northeast of the city of Bhuj depicts geologic structures that are of interest in the study the tectonic processes that may have led to that earthquake. However, preliminary field studies indicate that these structures are composed of Mesozoic rocks that are overlain by younger rocks showing little deformation. Thus these structures may be old, not actively growing, and not directly related to the recent earthquake.

    The Haro Hills are on the left and the Kas Hills are on the right. The Haro Hills are an 'anticline,' which is an upwardly convex elongated fold of layered rocks. In this view, the anticline is distinctly ringed by an erosion resistant layer of sandstone. The east-west orientation of the anticline may relate to the crustal compression that has occurred during India's northward movement toward, and collision with, Asia. In contrast, the largest of the Kas Hills appears to be a tilted (to the south) and faulted (on the north) block of layered rocks. Also seen here, the linear feature trending toward the southwest from the image center is an erosion-resistant 'dike,' which is an igneous intrusion into older 'host' rocks along a fault plane or other crack. These features are simple examples of how shaded topography can provide a direct input to geologic studies.

    In this image, colors show the elevation as measured by the Shuttle Radar Topography Mission (SRTM). Colors range from green at the lowest elevations, through yellow and red, to purple at the highest elevations. Elevations here range from near sea level to about 300 meters (about 1000 feet). Shading has been added, with illumination from the north (image top).

    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

  19. New Zealand, SRTM Shaded Relief and Colored Height

    NASA Technical Reports Server (NTRS)

    2004-01-01

    New Zealand straddles the juncture of the Indo-Australian and Pacific tectonic plates, two of Earth's major crustal plates. The two plates generally converge in subduction zones, but in a scissor-like pattern, with the Indo-Austalian plate overriding the Pacific plate to the north and the Pacific plate overriding the Indo-Australian plate to the south. New Zealand is 'what happens' in between at and near the cross point of this scissor pattern. Here the convergence has built two major islands that together exhibit very active volcanoes and fault systems, and these geologic features are very evident in the topographic pattern.

    The North Island lies at the southern end of the west-over-east (Indo-Australian over Pacific) plate convergence. The Pacific plate dives under the North Island and this subduction process leads to melting of rocks at depth, the rise of magma to the surface, and the formation of volcanoes and other geothermal features. Most notable are Mount Taranaki on the west coast, and Mounts Ruapehu, Ngauruhoe, and Tongariro just south of the island's centerpoint, all of which are shown with white peaks in this display. The Rotorua geothermal field occurs further northeast and is evident here as a scattering of comparatively small bumps created by smaller volcanic eruptions.

    The South Island straddles the cross point of the subduction scissor pattern and prominently features a fault system that connects the two subduction zones. (The east-over-west (Pacific over Indo-Australian) plate convergence generally occurs south of the South Island.) The Alpine fault is the major strand of this fault system along most of the length of the island, near and generally paralleling the west coast. Its impact upon the topography is unmistakable, forming an extremely sharp and straight northwest boundary to New Zealand's tallest mountains, the Southern Alps. Although offsets on the Alpine fault are generally right-lateral (35-40 millimeters per year) and

  20. Evaluating the Community Land Model in a pine stand with shading manipulations and 13CO2 labeling

    NASA Astrophysics Data System (ADS)

    Mao, J.; Ricciuto, D. M.; Thornton, P. E.; Warren, J. M.; King, A. W.; Shi, X.; Iversen, C. M.; Norby, R. J.

    2016-02-01

    Carbon allocation and flow through ecosystems regulates land surface-atmosphere CO2 exchange and thus is a key, albeit uncertain, component of mechanistic models. The Partitioning in Trees and Soil (PiTS) experiment-model project tracked carbon allocation through a young Pinus taeda stand following pulse labeling with 13CO2 and two levels of shading. The field component of this project provided process-oriented data that were used to evaluate terrestrial biosphere model simulations of rapid shifts in carbon allocation and hydrological dynamics under varying environmental conditions. Here we tested the performance of the Community Land Model version 4 (CLM4) in capturing short-term carbon and water dynamics in relation to manipulative shading treatments and the timing and magnitude of carbon fluxes through various compartments of the ecosystem. When calibrated with pretreatment observations, CLM4 was capable of closely simulating stand-level biomass, transpiration, leaf-level photosynthesis, and pre-labeling 13C values. Over the 3-week treatment period, CLM4 generally reproduced the impacts of shading on soil moisture changes, relative change in stem carbon, and soil CO2 efflux rate. Transpiration under moderate shading was also simulated well by the model, but even with optimization we were not able to simulate the high levels of transpiration observed in the heavy shading treatment, suggesting that the Ball-Berry conductance model is inadequate for these conditions. The calibrated version of CLM4 gave reasonable estimates of label concentration in phloem and in soil surface CO2 after 3 weeks of shade treatment, but it lacks the mechanisms needed to track the labeling pulse through plant tissues on shorter timescales. We developed a conceptual model for photosynthate transport based on the experimental observations, and we discussed conditions under which the hypothesized mechanisms could have an important influence on model behavior in larger-scale applications

  1. Direct Volume Rendering with Shading via Three-Dimensional Textures

    NASA Technical Reports Server (NTRS)

    Van Gelder, Allen; Kim, Kwansik

    1996-01-01

    A new and easy-to-implement method for direct volume rendering that uses 3D texture maps for acceleration, and incorporates directional lighting, is described. The implementation, called Voltx, produces high-quality images at nearly interactive speeds on workstations with hardware support for three-dimensional texture maps. Previously reported methods did not incorporate a light model, and did not address issues of multiple texture maps for large volumes. Our research shows that these extensions impact performance by about a factor of ten. Voltx supports orthographic, perspective, and stereo views. This paper describes the theory and implementation of this technique, and compares it to the shear-warp factorization approach. A rectilinear data set is converted into a three-dimensional texture map containing color and opacity information. Quantized normal vectors and a lookup table provide efficiency. A new tesselation of the sphere is described, which serves as the basis for normal-vector quantization. A new gradient-based shading criterion is described, in which the gradient magnitude is interpreted in the context of the field-data value and the material classification parameters, and not in isolation. In the rendering phase, the texture map is applied to a stack of parallel planes, which effectively cut the texture into many slabs. The slabs are composited to form an image.

  2. Effect of shading by the table coral Acropora Hyacinthus on understory corals. [Acropora; Pocillopora

    SciTech Connect

    Stimson, J.

    1985-02-01

    Field surveys at Enewetak Atoll, Marshall Islands, show that coral density and diversity is much lower beneath Acropora table corals than in adjacent unshaded areas. Additionally, the understory community is predominantly composed of massive and encrusting species, while branching Acropora and Pocillopora predominate in unshaded areas. Results of experiments in which coral fragments were transferred to the shade of table Acropora and to adjacent unshaded areas show that shading slows the growth and leads to higher mortality of branching species, while massive and encrusting species are unaffected. Light measurements made beneath table Acropora show that illumination and irradiance values fall to levels at which most hermatypic corals do not occur. The fast-growing but fragile table Acropora are abundant in a wide variety of atoll habitats and grow rapidly to form a canopy approx. = 50 cm above the substrate. However, table Acropora also have high mortality rates, so that there is continuous production of unshaded areas. The growth and death of tables thus create local disturbances, and the resulting patchwork of recently shaded and unshaded areas may enhance coral diversity in areas of high coral cover.

  3. Shaded relief, color as height, Fiji

    NASA Technical Reports Server (NTRS)

    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

  4. South America, Shaded Relief and Colored Height

    NASA Technical Reports Server (NTRS)

    2003-01-01

    that indicate the 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

  5. Zagros Mountains, Iran, SRTM Shaded Relief Anaglyph

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The Zagros Mountains in Iran offer a visually stunning topographic display of geologic structure in layered sedimentary rocks. This scene is nearly 100 kilometers (62 miles) wide but is only a small part of similar terrain that covers much of southern Iran. This area is actively undergoing crustal shortening, as global tectonics moves Arabia toward Asia. Consequently, layers of sedimentary rock are folding much like a carpet will fold if pushed. The convex upward folds create structures called anticlines, which are prominently seen here. The convex downward folds (between the anticlines) create structures called synclines, which are mostly buried and hidden by sediments eroding off the anticlines. Layers having differing erosional resistance create distinctive patterns, often sawtooth triangular facets, that encircle the anticlines. Local relief between the higher mountain ridges and their intervening valleys is about 1,200 meters (about 4,000 feet).

    Salt extrusions and salt 'glaciers' are another set of geologic features readily evident in the topography. Salt deposits, likely created by the evaporation of an ancient inland sea, were buried by the sediments that now make up the layers of the anticlines and synclines. But salt is less dense than most other rocks, so it tends to migrate upward through Earth's crust in vertical columns called 'diapirs'. The compressive folding process has probably facilitated the formation of these diapirs, and the diapirs, in turn, are probably enhancing some anticlines by 'inflating' them with salt. Where the diapirs reach the surface, the salt extrudes, much like lava from a volcano, and the salt flows. Two prominent salt flows are evident in the same valley, leaking from neighboring anticlines, just north of the scene center.

    This anaglyph was created by deriving a shaded relief image from the SRTM data, draping it back over the SRTM elevation model, and then generating two differing perspectives, one for each eye

  6. Zagros Mountains, Iran, SRTM Shaded Relief

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The Zagros Mountains in Iran offer a visually stunning topographic display of geologic structure in layered sedimentary rocks. This scene is nearly 100 kilometers (62 miles) wide but is only a small part of similar terrain that covers much of southern Iran. This area is actively undergoing crustal shortening, as global tectonics moves Arabia toward Asia. Consequently, layers of sedimentary rock are folding much like a carpet will fold if pushed. The convex upward folds create structures called anticlines, which are prominently seen here. The convex downward folds (between the anticlines) create structures called synclines, which are mostly buried and hidden by sediments eroding off the anticlines. Layers having differing erosional resistance create distinctive patterns, often sawtooth triangular facets, that encircle the anticlines. Local relief between the higher mountain ridges and their intervening valleys is about 1200 meters (about 4000 feet).

    Salt extrusions and salt 'glaciers' are another set of geologic features readily evident in the topography. Salt deposits, likely created by the evaporation of an ancient inland sea, were buried by the sediments that now make up the layers of the anticlines and synclines. But salt is less dense than most other rocks, so it tends to migrate upward through Earth's crust in vertical columns called 'diapirs'. The compressive folding process has probably facilitated the formation of these diapirs, and the diapirs, in turn, are probably enhancing some anticlines by 'inflating' them with salt. Where the diapirs reach the surface, the salt extrudes, much like lava from a volcano, and the salt flows. Two prominent salt flows are evident in the same valley, leaking from neighboring anticlines, just north of the scene center.

    This shaded relief image was created directly from an SRTM elevation model by computing topographic slope in the north-south direction. Northern slopes appear bright and southern slopes appear

  7. Effects of shading on the photosynthetic characteristics and mesophyll cell ultrastructure of summer maize.

    PubMed

    Ren, Baizhao; Cui, Haiyan; Camberato, James J; Dong, Shuting; Liu, Peng; Zhao, Bin; Zhang, Jiwang

    2016-08-01

    A field experiment was conducted to study the effects of shading on the photosynthetic characteristics and mesophyll cell ultrastructure of two summer maize hybrids Denghai605 (DH605) and Zhengdan958 (ZD958). The ambient sunlight treatment was used as control (CK) and shading treatments (40 % of ambient sunlight) were applied at different growth stages from silking (R1) to physiological maturity (R6) (S1), from the sixth leaf stage (V6) to R1 (S2), and from seeding to R6 (S3), respectively. The net photosynthetic rate (P n) was significantly decreased after shading. The greatest reduction of P n was found at S3 treatment, followed by S1 and S2 treatments. P n of S3 was decreased by 59 and 48 % for DH605, and 39 and 43 % for ZD958 at tasseling and milk-ripe stages, respectively, compared to that of CK. Additionally, leaf area index (LAI) and chlorophyll content decreased after shading. In terms of mesophyll cell ultrastructure, chloroplast configuration of mesophyll cells dispersed, and part of chloroplast swelled and became circular. Meanwhile, the major characteristics of chloroplasts showed poorly developed thylakoid structure at the early growth stage, blurry lamellar structure, loose grana, and a large gap between slices and warping granum. Then, plasmolysis occurred in mesophyll cells and the endomembrane system was destroyed, which resulted in the dissolution of cell membrane, karyotheca, mitochondria, and some membrane structures. The damaged mesophyll cell ultrastructure led to the decrease of photosynthetic capacity, and thus resulted in significant yield reduction by 45, 11, and 84 % in S1, S2, and S3 treatments, respectively, compared to that of CK. PMID:27437706

  8. Effects of shading on the photosynthetic characteristics and mesophyll cell ultrastructure of summer maize.

    PubMed

    Ren, Baizhao; Cui, Haiyan; Camberato, James J; Dong, Shuting; Liu, Peng; Zhao, Bin; Zhang, Jiwang

    2016-08-01

    A field experiment was conducted to study the effects of shading on the photosynthetic characteristics and mesophyll cell ultrastructure of two summer maize hybrids Denghai605 (DH605) and Zhengdan958 (ZD958). The ambient sunlight treatment was used as control (CK) and shading treatments (40 % of ambient sunlight) were applied at different growth stages from silking (R1) to physiological maturity (R6) (S1), from the sixth leaf stage (V6) to R1 (S2), and from seeding to R6 (S3), respectively. The net photosynthetic rate (P n) was significantly decreased after shading. The greatest reduction of P n was found at S3 treatment, followed by S1 and S2 treatments. P n of S3 was decreased by 59 and 48 % for DH605, and 39 and 43 % for ZD958 at tasseling and milk-ripe stages, respectively, compared to that of CK. Additionally, leaf area index (LAI) and chlorophyll content decreased after shading. In terms of mesophyll cell ultrastructure, chloroplast configuration of mesophyll cells dispersed, and part of chloroplast swelled and became circular. Meanwhile, the major characteristics of chloroplasts showed poorly developed thylakoid structure at the early growth stage, blurry lamellar structure, loose grana, and a large gap between slices and warping granum. Then, plasmolysis occurred in mesophyll cells and the endomembrane system was destroyed, which resulted in the dissolution of cell membrane, karyotheca, mitochondria, and some membrane structures. The damaged mesophyll cell ultrastructure led to the decrease of photosynthetic capacity, and thus resulted in significant yield reduction by 45, 11, and 84 % in S1, S2, and S3 treatments, respectively, compared to that of CK.

  9. Shaded relief, color as height, Salalah, Oman

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This elevation map shows a part of the southern coast of the Arabian Peninsula including parts of the countries of Oman and Yemen. The narrow coastal plain on the right side of the image includes the city of Salahlah, the second largest city in Oman. Various crops, including coconuts, papayas and bananas, are grown on this plain. The abrupt topography of the coastal mountains wrings moisture from the monsoon, enabling agriculture in the otherwise dry environment of the Arabian Peninsula. These mountains are historically significant as well: Some scholars believe these mountains are the 'southern mountains' of the book of Genesis.

    This image brightness corresponds to shading illumination from the right, while colors show the elevation as measured by the Shuttle Radar Topography Mission. Colors range from green at the lowest elevations to brown at the highest elevations. This image contains about 1400 meters (4600 feet) of total relief. The Arabian Sea is colored blue.

    The Shuttle Radar Topography Mission (SRTM), launched on February 11, 2000, 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. The 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, an additional C-band imaging antenna and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) and the German (DLR) and Italian (ASI)space agencies. It is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Earth Science Enterprise, Washington, DC.

    Size: 149 by 40 kilometers (92 by 25 miles) Location: 16.9 deg. North lat., 53.7 deg. East lon. Orientation: North at top right Date Acquired: February 15, 2000 Image: NASA/JPL/NIMA

  10. South America, Shaded Relief and Colored Height

    NASA Technical Reports Server (NTRS)

    2003-01-01

    that indicate the 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

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

    NASA Astrophysics Data System (ADS)

    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

  12. Image-domain shading correction for cone-beam CT without prior patient information.

    PubMed

    Fan, Qiyong; Lu, Bo; Park, Justin C; Niu, Tianye; Li, Jonathan G; Liu, Chihray; Zhu, Lei

    2015-01-01

    In the era of high-precision radiotherapy, cone-beam CT (CBCT) is frequently utilized for on-board treatment guidance. However, CBCT images usually contain severe shading artifacts due to strong photon scatter from illumination of a large volume and non-optimized patient-specific data measurements, limiting the full clinical applications of CBCT. Many algorithms have been proposed to alleviate this problem by data correction on projections. Sophisticated methods have also been designed when prior patient information is available. Nevertheless, a standard, efficient, and effective approach with large applicability remains elusive for current clinical practice. In this work, we develop a novel algorithm for shading correction directly on CBCT images. Distinct from other image-domain correction methods, our approach does not rely on prior patient information or prior assumption of patient data. In CBCT, projection errors (mostly from scatter and non-ideal usage of bowtie filter) result in dominant low-frequency shading artifacts in image domain. In circular scan geometry, these artifacts often show global or local radial patterns. Hence, the raw CBCT images are first preprocessed into the polar coordinate system. Median filtering and polynomial fitting are applied on the transformed image to estimate the low-frequency shading artifacts (referred to as the bias field) angle-by-angle and slice-by-slice. The low-pass filtering process is done firstly along the angular direction and then the radial direction to preserve image contrast. The estimated bias field is then converted back to the Cartesian coordinate system, followed by 3D low-pass filtering to eliminate possible high-frequency components. The shading-corrected image is finally obtained as the uncorrected volume divided by the bias field. The proposed algorithm was evaluated on CBCT images of a pelvis patient and a head patient. Mean CT number values and spatial non-uniformity on the reconstructed images were

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

    SciTech Connect

    MacAlpine, Sara; Deline, Chris

    2015-06-14

    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.

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

    SciTech Connect

    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.

  15. Convergence of CONSTITUTIVE PHOTOMORPHOGENESIS 1 and PHYTOCHROME INTERACTING FACTOR signalling during shade avoidance.

    PubMed

    Pacín, Manuel; Semmoloni, Mariana; Legris, Martina; Finlayson, Scott A; Casal, Jorge J

    2016-08-01

    Shade-avoidance responses require CONSTITUTIVE PHOTOMORPHOGENESIS 1 (COP1) but the mechanisms of action of COP1 under shade have not been elucidated. Using simulated shade and control conditions, we analysed: the transcriptome and the auxin levels of cop1 and phytochrome interacting factor 1 (pif1) pif3 pif4 pif5 (pifq) mutants; the dynamics of ELONGATED HYPOCOTYL 5 (HY5) and LONG HYPOCOTYL IN FAR-RED (HFR1) proteins; and the epistatic relationships between cop1 and pif3, pif4, pif5, hy5 and hfr1 mutations in Arabidopsis thaliana. Despite severely impaired shade-avoidance responses, only a few genes that responded to shade in the wild-type failed to do so in cop1. Shade enhanced the convergence between cop1 and pifq transcriptomes, mainly on shade-avoidance marker genes. Shade failed to increase auxin levels in cop1. Residual shade avoidance in cop1 was not further reduced by the pif3, pif4 or pif5 mutations, suggesting convergent pathways. HFR1 stability decreased under shade in a COP1-dependent manner but shade increased HY5 stability. The cop1 mutant retains responses to shade and is more specifically impaired in shade avoidance. COP1 promotes the degradation of HFR1 under shade, thus increasing the ability of PIFs to control gene expression, increase auxin levels and promote stem growth.

  16. Convergence of CONSTITUTIVE PHOTOMORPHOGENESIS 1 and PHYTOCHROME INTERACTING FACTOR signalling during shade avoidance.

    PubMed

    Pacín, Manuel; Semmoloni, Mariana; Legris, Martina; Finlayson, Scott A; Casal, Jorge J

    2016-08-01

    Shade-avoidance responses require CONSTITUTIVE PHOTOMORPHOGENESIS 1 (COP1) but the mechanisms of action of COP1 under shade have not been elucidated. Using simulated shade and control conditions, we analysed: the transcriptome and the auxin levels of cop1 and phytochrome interacting factor 1 (pif1) pif3 pif4 pif5 (pifq) mutants; the dynamics of ELONGATED HYPOCOTYL 5 (HY5) and LONG HYPOCOTYL IN FAR-RED (HFR1) proteins; and the epistatic relationships between cop1 and pif3, pif4, pif5, hy5 and hfr1 mutations in Arabidopsis thaliana. Despite severely impaired shade-avoidance responses, only a few genes that responded to shade in the wild-type failed to do so in cop1. Shade enhanced the convergence between cop1 and pifq transcriptomes, mainly on shade-avoidance marker genes. Shade failed to increase auxin levels in cop1. Residual shade avoidance in cop1 was not further reduced by the pif3, pif4 or pif5 mutations, suggesting convergent pathways. HFR1 stability decreased under shade in a COP1-dependent manner but shade increased HY5 stability. The cop1 mutant retains responses to shade and is more specifically impaired in shade avoidance. COP1 promotes the degradation of HFR1 under shade, thus increasing the ability of PIFs to control gene expression, increase auxin levels and promote stem growth. PMID:27105120

  17. Plant Responses to Vegetation Proximity: A Whole Life Avoiding Shade.

    PubMed

    Roig-Villanova, Irma; Martínez-García, Jaime F

    2016-01-01

    In high density of vegetation, plants detect neighbors by perceiving changes in light quality through phytochrome photoreceptors. Close vegetation proximity might result in competition for resources, such as light. To face this challenge, plants have evolved two alternative strategies: to either tolerate or avoid shade. Shade-avoiding species generally adapt their development by inducing hypocotyl, stem, and petiole elongation, apical dominance and flowering, and decreasing leaf expansion and yield, a set of responses collectively known as the shade avoidance syndrome (SAS). The SAS responses have been mostly studied at the seedling stage, centered on the increase of hypocotyl elongation. After compiling the main findings about SAS responses in seedlings, this review is focused on the response to shade at adult stages of development, such as petioles of adult leaves, and the little information available on the SAS responses in reproductive tissues. We discuss these responses based on the knowledge about the molecular mechanisms and components with a role in regulating the SAS response of the hypocotyls of Arabidopsis thaliana. The transcriptional networks involved in this process, as well as the communication among the tissues that perceive the shade and the ones that respond to this stimulus will also be briefly commented. PMID:26973679

  18. Plant Responses to Vegetation Proximity: A Whole Life Avoiding Shade

    PubMed Central

    Roig-Villanova, Irma; Martínez-García, Jaime F.

    2016-01-01

    In high density of vegetation, plants detect neighbors by perceiving changes in light quality through phytochrome photoreceptors. Close vegetation proximity might result in competition for resources, such as light. To face this challenge, plants have evolved two alternative strategies: to either tolerate or avoid shade. Shade-avoiding species generally adapt their development by inducing hypocotyl, stem, and petiole elongation, apical dominance and flowering, and decreasing leaf expansion and yield, a set of responses collectively known as the shade avoidance syndrome (SAS). The SAS responses have been mostly studied at the seedling stage, centered on the increase of hypocotyl elongation. After compiling the main findings about SAS responses in seedlings, this review is focused on the response to shade at adult stages of development, such as petioles of adult leaves, and the little information available on the SAS responses in reproductive tissues. We discuss these responses based on the knowledge about the molecular mechanisms and components with a role in regulating the SAS response of the hypocotyls of Arabidopsis thaliana. The transcriptional networks involved in this process, as well as the communication among the tissues that perceive the shade and the ones that respond to this stimulus will also be briefly commented. PMID:26973679

  19. SHADE: A Shape-Memory-Activated Device Promoting Ankle Dorsiflexion

    NASA Astrophysics Data System (ADS)

    Pittaccio, S.; Viscuso, S.; Rossini, M.; Magoni, L.; Pirovano, S.; Villa, E.; Besseghini, S.; Molteni, F.

    2009-08-01

    Acute post-stroke rehabilitation protocols include passive mobilization as a means to prevent contractures. A device (SHADE) that provides repetitive passive motion to a flaccid ankle by using shape memory alloy actuators could be of great help in providing this treatment. A suitable actuator was designed as a cartridge of approximately 150 × 20 × 15 mm, containing 2.5 m of 0.25 mm diameter NiTi wire. This actuator was activated by Joule’s effect employing a 7 s current input at 0.7 A, which provided 10 N through 76 mm displacement. Cooling and reset by natural convection took 30 s. A prototype of SHADE was assembled with two thermoplastic shells hinged together at the ankle and strapped on the shin and foot. Two actuators were fixed on the upper shell while an inextensible thread connected each NiTi wire to the foot shell. The passive ankle motion (passive range of motion, PROM) generated by SHADE was evaluated optoelectronically on three flaccid patients (58 ± 5 years old); acceptability was assessed by a questionnaire presented to further three flaccid patients (44 ± 11.5 years old) who used SHADE for 5 days, 30 min a day. SHADE was well accepted by all patients, produced good PROM, and caused no pain. The results prove that suitable limb mobilization can be produced by SMA actuators.

  20. Shading as a Control Method for Invasive European Frogbit (Hydrocharis morsus-ranae L.)

    PubMed Central

    Zhu, Bin; Ellis, Michael S.; Fancher, Kelly L.; Rudstam, Lars G.

    2014-01-01

    Invasive European frogbit (Hydrocharis morsus-ranae L.) has negative environmental and economic impacts in North American water bodies. It is therefore important to develop effective management tools to control this invasive species. This study investigated shading as a control method for European frogbit in both greenhouse and lake mesocosm experiments. A series of shade treatments (0%, 50%, 60%, 70%, 80%, and 100%) were tested in the greenhouse for three weeks. Results showed that the 100% shade was most effective at controlling European frogbit, and other shade treatments greater than 50% were less effective, reducing frogbit biomass up to 38.2%. There were no differences found in temperature between treatments, but dissolved oxygen decreased as shading increased. A lake mesocosm experiment utilizing 0% shade, 70% shade, and 100% shade treatments was performed in a sheltered inlet of Oneida Lake in New York State for over one month. Resulting European frogbit biomass was significantly (25 times) less in areas treated with the 70% shade and nearly zero with the 100% shade. Shading did not affect temperature but improved DO conditions. Results on the shading effects on submerged macrophytes were not conclusive: no significant differences in changes in species richness and abundance between the three groups at the end of studied period suggested no shading effects; significant differences between the beginning and end communities in the 70% shade and the 100% shade but not in the control group indicated significant impacts of shading. This study is the first one to investigate shading as a control method for European frogbit and it is concluded that a moderately high density shade can effective remove European frogbit likely with minor impacts on the environment. More experiments with larger scales and longer time periods are recommended for further investigation. PMID:24886916

  1. Resprouting as a persistence strategy of tropical forest trees: relations with carbohydrate storage and shade tolerance.

    PubMed

    Poorter, Lourens; Kitajima, Kaoru; Mercado, Pablo; Chubiña, Jose; Melgar, Israel; Prins, Herbert H T

    2010-09-01

    Resprouting is an important persistence strategy for woody species and represents a dominant pathway of regeneration in many plant communities, with potentially large consequences for vegetation dynamics, community composition, and species coexistence. Most of our knowledge of resprouting strategies comes from fire-prone systems, but this cannot be readily applied to other systems where disturbances are less intense. In this study we evaluated sapling responses to stem snapping for 49 moist-forest species and 36 dry-forest species from two Bolivian tropical forests. To this end we compared in a field experiment the survival and height growth of clipped and control saplings for a two-year period, and related this to the shade tolerance, carbohydrate reserves, and the morphological traits (wood density, leaf size) of the species. Nearly all saplings resprouted readily after stem damage, although dry-forest species realized, on average, a better survival and growth after stem damage compared to moist-forest species. Shade-tolerant species were better at resprouting than light-demanding species in moist forest. This resprouting ability is an important prerequisite for successful regeneration in the shaded understory, where saplings frequently suffer damage from falling debris. Survival after stem damage was, surprisingly, only modestly related to stem reserves, and much more strongly related to wood density, possibly because a high wood density enables plants to resist fungi and pathogens and to reduce stem decay. Correlations between sampling performance and functional traits were similar for the two forest types, and for phylogenetically independent contrasts and for cross-species analyses. The consistency of these results suggests that tropical forest species face similar trade-offs in different sites and converge on similar sets of solutions. A high resprouting ability, as well as investments in stem defense and storage reserves, form part of a suite of co

  2. Shade, water and mass: Passive cooling in Andalucia

    SciTech Connect

    Carrasco, V.; Reynolds, J.S.

    1996-10-01

    A thermally massive, ancient patio (courtyard) house in Bornos Spain was monitored for 25 days in summer 1995. Data for light, relative humidity and air temperature were recorded at the floor`s center in the 3-story deep patio. Temperatures were also recorded in one ground floor and one second floor room adjacent to the patio, and on the roof terrace. Victor Carrasco (the owner) kept a daily record of his actions of shading (with a toldo), of watering the patio`s absorbent floor, and of opening windows for night ventilation. The data show the effects of shading, watering and night ventilation. The cycles of temperature and relative humidity in the center of the patio floor reveal a pattern of thermal sailing where skillful manipulations of shading, evaporative cooling, radiation and night ventilation result in indoor comfort despite the highest outside temperatures of this century that occurred in late July 1995.

  3. Analysis and conceptual design of a lunar radiator parabolic shade

    NASA Technical Reports Server (NTRS)

    Ewert, Michael K.; Clark, Craig S.

    1991-01-01

    On the moon, the available heat sink temperature for a vertical unshaded radiator at the equator is 322 K. A method of reducing this heat sink temperature using a parabolic trough shading device was investigated. A steady state heat balance was performed to predict the available heat sink temperature. The effect of optical surface properties on system performance was investigated. Various geometric configurations were also evaluated. A flexible shade conceptual design is presented which greatly reduces the weight and stowed volume of the system. The concept makes use of the natural catenary shape assumed by a flexible material when supported at two points. The catenary shape is very near parabolic. The lunar radiator parabolic shade design presented integrates the energy collection and rejection of a solar dynamic power cycle with the moderate temperature waste heat rejection of a lunar habitat.

  4. Objective measurement of shade color in age estimation

    PubMed Central

    Vaidya, Sharad; Ahuja, Nitin; Bajaj, Puneet; Kapoor, Charu; Sabarwal, Robin; Rajpal, Karan

    2015-01-01

    Introduction: Age estimation is an important subspecialty of forensic medicine. Dental hard tissues are highly resistant to degradation and putrefaction. Enamel is translucent and varies in color from light yellow to grey white. The color of the teeth has been reported to be affected by chronological age. Enamel color may also depend on environmental factors viz. diet, occupational habits, vitamin deficiencies, fluoride level in drinking water etc., It has been found that color changes in dentin vary from white to yellow. Studies have been done to measure the dentin color for age estimation. Aim: To find a correlation between the enamel color and chronological age and secondly to estimate the age of an individual from enamel color. Material and Methods: A total of 300 patients visiting the outpatient department of oral medicine and radiology were selected. Out of those, 150 were men and 150 women. The patients were divided into V groups based on the age. A thorough case history was taken for all the patients. Maxillary Central and Lateral incisor was used for the estimation of shade. The enamel color was evaluated using a VITA classical shade guide. Statistical Analysis: Data were exported to an Excel spread sheet and statistical analysis was performed using the SPSS. Linear regression analysis was used to find correlations between age and enamel shade. Results: In the group 1 and 2 i.e. from 15 to 36 years, the shades A 2 and B 2 (reddish hue) was found to be most common. While in the group 3 and 4, shades ranged from A 3 to B 3 (brownish to yellowish hue). In the patients above 59 years i.e. group 5 the enamel shade with greyish hue was found to be most common. Conclusion: Age determination using enamel color can be tried in forensic cases in the identification of individuals with no birth records. PMID:26816455

  5. Modeling Tree Shade Effect on Urban Ground Surface Temperature.

    PubMed

    Napoli, Marco; Massetti, Luciano; Brandani, Giada; Petralli, Martina; Orlandini, Simone

    2016-01-01

    There is growing interest in the role that urban forests can play as urban microclimate modifiers. Tree shade and evapotranspiration affect energy fluxes and mitigate microclimate conditions, with beneficial effects on human health and outdoor comfort. The aim of this study was to investigate surface temperature () variability under the shade of different tree species and to test the capability in predicting of a proposed heat transfer model. Surface temperature data on asphalt and grass under different shading conditions were collected in the Cascine park, Florence, Italy, and were used to test the performance of a one-dimensional heat transfer model integrated with a routine for estimating the effect of plant canopies on surface heat transfer. Shading effects of 10 tree species commonly used in Italian urban settings were determined by considering the infrared radiation and the tree canopy leaf area index (LAI). The results indicate that, on asphalt, was negatively related to the LAI of trees ( reduction ranging from 13.8 to 22.8°C). On grass, this relationship was weaker probably because of the combined effect of shade and grass evapotranspiration on ( reduction ranged from 6.9 to 9.4°C). A sensitivity analysis confirmed that other factors linked to soil water content play an important role in reduction of grassed areas. Our findings suggest that the energy balance model can be effectively used to estimate of the urban pavement under different shading conditions and can be applied to the analysis of microclimate conditions of urban green spaces. PMID:26828170

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

    PubMed

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

    PubMed

    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. PMID:26318296

  8. Iterative CT shading correction with no prior information

    NASA Astrophysics Data System (ADS)

    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. Differences in tooth shade value according to age, gender and skin color: A pilot study

    PubMed Central

    Veeraganta, Sumanth K.; Savadi, Ravindra C.; Baroudi, Kusai; Nassani, Mohammad Z.

    2015-01-01

    Purpose of the Study: The purpose was to investigate the differences in tooth shade value according to age, gender and skin color among a sample of the local population in Bengaluru, India. Methodology: The study comprised 100 subjects belonging to both gender between the age groups of 16 years to 55 years. Tooth shade values of permanent maxillary left or right central incisors were recorded using the Vitapan 3D-Master shade guide. Skin color was matched using the Radiance compact makeup shades as a guide. Results: Chi-square statistical test demonstrated that younger subjects have lighter tooth shade values. No statistically significant differences were recorded in tooth shade value according to gender or skin color. Conclusion: Within the limitations of the current study, it can be concluded that tooth shade value is significantly influenced by age. Gender and skin color appear not to have a significant relation to tooth shade value. PMID:26929500

  10. Electron-shading effect on the horizontal aligned growth of carbon nanotubes

    SciTech Connect

    Chai Yang; Xiao Zhiyong; Chan, Philip C. H.

    2009-01-26

    Based on the well-accepted electron-shading theory during plasma processing, we designed microstructures to control the local built-in electric-field on the substrate surface. The distortion magnitude of the electric-field is largest near the sidewalls of the microstructures, creating a horizontal electric-field in this region. We showed that the horizontally aligned carbon nanotubes (CNTs) were grown by making use of this built-in electric-field during the plasma-enhanced chemical vapor deposition process, with a tactical choice of geometries and materials of the microstructures on the substrate. This technique opens up a way to selectively and controllably grow horizontally aligned CNTs on the substrate surface.

  11. Winter shading of blueberry plants in the southeastern United States

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In Central Florida, southern highbush blueberries are treated with hydrogen cyanamide to replace lack of chilling and enhance flowering and fruiting. Experiments were conducted to determine the effects of repeated applications of processed kaolin particle and flat-top shade structure on blueberry p...

  12. Shade images of forested areas obtained from LANDSAT MSS data

    NASA Technical Reports Server (NTRS)

    Shimabukuro, Yosio Edemir; Smith, James A.

    1989-01-01

    The pixel size in the present day Remote Sensing systems is large enough to include different types of land cover. Depending upon the target area, several components may be present within the pixel. In forested areas, generally, three main components are present: tree canopy, soil (understory), and shadow. The objective is to generate a shade (shadow) image of forested areas from multispectral measurements of LANDSAT MSS (Multispectral Scanner) data by implementing a linear mixing model, where shadow is considered as one of the primary components in a pixel. The shade images are related to the observed variation in forest structure, i.e., the proportion of inferred shadow in a pixel is related to different forest ages, forest types, and tree crown cover. The Constrained Least Squares (CLS) method is used to generate shade images for forest of eucalyptus and vegetation of cerrado using LANDSAT MSS imagery over Itapeva study area in Brazil. The resulted shade images may explain the difference on ages for forest of eucalyptus and the difference on three crown cover for vegetation of cerrado.

  13. Evaluating shading bias in malaise and intercept traps

    USGS Publications Warehouse

    Irvine, Kathryn M.; Woods, Stephen A.

    2007-01-01

    Foresters are increasingly focusing on landscape level management regimes. At the landscape level, managed acreage may differ substantially in structure and micro-climatic conditions. Trapping is a commonly used method to evaluate changes in insect communities across landscapes. Among those trapping techniques, Malaise and window-pane traps are conveniently deployed to collect large numbers of insects for relative estimates of density. However, the catch within traps may be affected by a wide range of environmental variables including trap location, height, and factors such as exposure to sunlight and temperature. Seven experiments were conducted from 1996 through 2000 to evaluate the effects of shading on trap catch of a variety of Malaise trap designs and one window-pane trap design. Overall, differences in shading effects on trap catch were detected across different traps and taxa and suggested that, in general, more insects are collected in traps that were in direct sunlight. The effect of shading varied from a reduction in trap catch of 10 % to an increase of 7%, the results depended on trap color. Diptera, Coleoptera, and Homoptera were most likely to exhibit this bias. In contrast, trap catch of the Hymenoptera was the most variable and appeared to be sensitive to factors that might interact with sun/shade conditions

  14. Reproductive efficiency and shade avoidance plasticity under simulated competition.

    PubMed

    Fazlioglu, Fatih; Al-Namazi, Ali; Bonser, Stephen P

    2016-07-01

    Plant strategy and life-history theories make different predictions about reproductive efficiency under competition. While strategy theory suggests under intense competition iteroparous perennial plants delay reproduction and semelparous annuals reproduce quickly, life-history theory predicts both annual and perennial plants increase resource allocation to reproduction under intense competition. We tested (1) how simulated competition influences reproductive efficiency and competitive ability (CA) of different plant life histories and growth forms; (2) whether life history or growth form is associated with CA; (3) whether shade avoidance plasticity is connected to reproductive efficiency under simulated competition. We examined plastic responses of 11 herbaceous species representing different life histories and growth forms to simulated competition (spectral shade). We found that both annual and perennial plants invested more to reproduction under simulated competition in accordance with life-history theory predictions. There was no significant difference between competitive abilities of different life histories, but across growth forms, erect species expressed greater CA (in terms of leaf number) than other growth forms. We also found that shade avoidance plasticity can increase the reproductive efficiency by capitalizing on the early life resource acquisition and conversion of these resources into reproduction. Therefore, we suggest that a reassessment of the interpretation of shade avoidance plasticity is necessary by revealing its role in reproduction, not only in competition of plants.

  15. VIEW OF SHADED REAR YARD WITH CHAINLINK FENCE AND TERRACING, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF SHADED REAR YARD WITH CHAINLINK FENCE AND TERRACING, BEHIND 559 BIRCH CIRCLE. VIEW FACING EAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  16. VIEW OF SHADED REAR YARDS AND TERRACING, SHOWING REAR OF ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF SHADED REAR YARDS AND TERRACING, SHOWING REAR OF 527 BIRCH CIRCLE ON LEFT. VIEW FACING NORTHEAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  17. VIEW OF EAST SIDE OF CEDAR DRIVE, SHOWING SHADED CANOPY ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF EAST SIDE OF CEDAR DRIVE, SHOWING SHADED CANOPY FORMED BY MONKEYPOD TREES. VIEW FACING EAST - Camp H.M. Smith and Navy Public Works Center Manana Title VII (Capehart) Housing, Intersection of Acacia Road and Brich Circle, Pearl City, Honolulu County, HI

  18. Reproductive efficiency and shade avoidance plasticity under simulated competition.

    PubMed

    Fazlioglu, Fatih; Al-Namazi, Ali; Bonser, Stephen P

    2016-07-01

    Plant strategy and life-history theories make different predictions about reproductive efficiency under competition. While strategy theory suggests under intense competition iteroparous perennial plants delay reproduction and semelparous annuals reproduce quickly, life-history theory predicts both annual and perennial plants increase resource allocation to reproduction under intense competition. We tested (1) how simulated competition influences reproductive efficiency and competitive ability (CA) of different plant life histories and growth forms; (2) whether life history or growth form is associated with CA; (3) whether shade avoidance plasticity is connected to reproductive efficiency under simulated competition. We examined plastic responses of 11 herbaceous species representing different life histories and growth forms to simulated competition (spectral shade). We found that both annual and perennial plants invested more to reproduction under simulated competition in accordance with life-history theory predictions. There was no significant difference between competitive abilities of different life histories, but across growth forms, erect species expressed greater CA (in terms of leaf number) than other growth forms. We also found that shade avoidance plasticity can increase the reproductive efficiency by capitalizing on the early life resource acquisition and conversion of these resources into reproduction. Therefore, we suggest that a reassessment of the interpretation of shade avoidance plasticity is necessary by revealing its role in reproduction, not only in competition of plants. PMID:27547325

  19. Shading responses of carbon allocation dynamics in mountain grassland

    NASA Astrophysics Data System (ADS)

    Bahn, M.; Lattanzi, F. A.; Brueggemann, N.; Siegwolf, R. T.; Richter, A.

    2012-12-01

    Carbon (C) allocation strongly influences plant and soil processes. Global environmental changes can alter source - sink relations of plants with potential implications for C allocation. Short-term C allocation dynamics in ecosystems and their responses to environmental changes are still poorly understood. To analyze effects of assimilate supply (i.e. C source strength) on ecosystem C allocation dynamics and the role of non-structural carbohydrates, canopy sections of a mountain meadow were pulse labeled with 13CO2 and subsequently shaded for a week or left unshaded (control). Tracer dynamics in above- and belowground sucrose and starch pools were analysed and coupled using compartmental modelling. The hypothesis was tested that shading affects tracer dynamics in non-structural carbohydrates and diminishes the transfer of recently assimilated C to roots and their storage pools. In unshaded plots up to 40% of assimilated C was routed through short-term storage in shoot starch and sucrose to buffer day / night cycles in photosynthesis. Shoot- and root sucrose and shoot starch were kinetically closely related pools. The tracer dynamics of the modelled root sucrose pool corresponded well with those in soil CO2 efflux. Root starch played no role in buffering day / night cycles and likely acted as a seasonal store. Shading strongly reduced sucrose and starch concentrations in shoots but not roots and resulted in a massive reduction of leaf respiration, while root respiration was much less diminished. Shading affected tracer dynamics in sucrose and starch of shoots: shoot starch rapidly lost tracer, while sucrose transiently increased its tracer content. Surprisingly, shading did not alter the dynamics of root carbohydrates. Even under severe C limitation after one week of shading, tracer C continued to be incorporated in root starch. Also the amount of 13C incorporated in phospholipid fatty acids of soil microbial communities was not reduced by shading, though its

  20. Proximity signal and shade avoidance differences between early and late successional trees.

    PubMed

    Gilbert, I R; Jarvis, P G; Smith, H

    2001-06-14

    Competitive interactions between plants determine the success of individuals and species. In developing forests, competition for light is the predominant factor. Shade tolerators acclimate photosynthetically to low light and are capable of long-term survival under the shade cast by others, whereas shade avoiders rapidly dominate gaps but are overtaken in due course by shade-tolerant, later successional species. Shade avoidance results from the phytochrome-mediated perception of far-red radiation (700-800 nm) scattered from the leaves of neighbours, provides early warning of shading, and induces developmental responses that, when successful, result in the overgrowth of those neighbours. Shade tolerators cast a deep shade, whereas less-tolerant species cast light shade, and saplings tend to have high survivorship in shade cast by conspecific adults, but high rates of mortality when shaded by more-tolerant species. Here we report a parallel relationship in which the shade-avoidance responses of three tree species are inversely proportional to proximity signals generated by those species. On this basis, early successional species generate small proximity signals but react strongly to them, whereas late successional species react weakly but generate strong signals.

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 ...

  2. 29 CFR 780.506 - Dependence of exemption on shade-grown tobacco operations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Dependence of exemption on shade-grown tobacco operations... FAIR LABOR STANDARDS ACT Employment or Agricultural Employees in Processing Shade-Grown Tobacco; Exemption From Minimum Wage and Overtime Pay Requirements Under Section 13(a)(14) Shade-Grown Tobacco §...

  3. 29 CFR 780.506 - Dependence of exemption on shade-grown tobacco operations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Dependence of exemption on shade-grown tobacco operations... FAIR LABOR STANDARDS ACT Employment or Agricultural Employees in Processing Shade-Grown Tobacco; Exemption From Minimum Wage and Overtime Pay Requirements Under Section 13(a)(14) Shade-Grown Tobacco §...

  4. 29 CFR 780.505 - Definition of “shade-grown tobacco.”

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 3 2012-07-01 2012-07-01 false Definition of âshade-grown tobacco.â 780.505 Section 780... Employment or Agricultural Employees in Processing Shade-Grown Tobacco; Exemption From Minimum Wage and Overtime Pay Requirements Under Section 13(a)(14) Shade-Grown Tobacco § 780.505 Definition of...

  5. 29 CFR 780.506 - Dependence of exemption on shade-grown tobacco operations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false Dependence of exemption on shade-grown tobacco operations... FAIR LABOR STANDARDS ACT Employment or Agricultural Employees in Processing Shade-Grown Tobacco; Exemption From Minimum Wage and Overtime Pay Requirements Under Section 13(a)(14) Shade-Grown Tobacco §...

  6. 29 CFR 780.505 - Definition of “shade-grown tobacco.”

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 3 2014-07-01 2014-07-01 false Definition of âshade-grown tobacco.â 780.505 Section 780... Employment or Agricultural Employees in Processing Shade-Grown Tobacco; Exemption From Minimum Wage and Overtime Pay Requirements Under Section 13(a)(14) Shade-Grown Tobacco § 780.505 Definition of...

  7. 29 CFR 780.506 - Dependence of exemption on shade-grown tobacco operations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Dependence of exemption on shade-grown tobacco operations... FAIR LABOR STANDARDS ACT Employment or Agricultural Employees in Processing Shade-Grown Tobacco; Exemption From Minimum Wage and Overtime Pay Requirements Under Section 13(a)(14) Shade-Grown Tobacco §...

  8. 29 CFR 780.506 - Dependence of exemption on shade-grown tobacco operations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Dependence of exemption on shade-grown tobacco operations... FAIR LABOR STANDARDS ACT Employment or Agricultural Employees in Processing Shade-Grown Tobacco; Exemption From Minimum Wage and Overtime Pay Requirements Under Section 13(a)(14) Shade-Grown Tobacco §...

  9. 29 CFR 780.505 - Definition of “shade-grown tobacco.”

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 3 2013-07-01 2013-07-01 false Definition of âshade-grown tobacco.â 780.505 Section 780... Employment or Agricultural Employees in Processing Shade-Grown Tobacco; Exemption From Minimum Wage and Overtime Pay Requirements Under Section 13(a)(14) Shade-Grown Tobacco § 780.505 Definition of...

  10. 29 CFR 780.505 - Definition of “shade-grown tobacco.”

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Definition of âshade-grown tobacco.â 780.505 Section 780... Employment or Agricultural Employees in Processing Shade-Grown Tobacco; Exemption From Minimum Wage and Overtime Pay Requirements Under Section 13(a)(14) Shade-Grown Tobacco § 780.505 Definition of...

  11. 29 CFR 780.505 - Definition of “shade-grown tobacco.”

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 3 2010-07-01 2010-07-01 false Definition of âshade-grown tobacco.â 780.505 Section 780... Employment or Agricultural Employees in Processing Shade-Grown Tobacco; Exemption From Minimum Wage and Overtime Pay Requirements Under Section 13(a)(14) Shade-Grown Tobacco § 780.505 Definition of...

  12. The effect of resin shades on microhardness, polymerization shrinkage, and color change of dental composite resins.

    PubMed

    Jeong, Tae-Sung; Kang, Ho-Seung; Kim, Sung-Ki; Kim, Shin; Kim, Hyung-Il; Kwon, Yong Hoon

    2009-07-01

    The present study sought to evaluate the effect of resin shades on the degree of the polymerization. To this end, response variables affected by the degree of polymerization were examined in this study - namely, microhardness, polymerization shrinkage, and color change. Two commercial composite resins of four different shades were employed in this study: shades A3, A3.5, B3, and C3 of Z250 (Z2) and shades A3, A3.5, B3, and B4 of Solitaire 2 (S2). After light curing, the reflectance/absorbance, microhardness, polymerization shrinkage, and color change of the specimens were measured. On reflectance and absorbance, Z2 and S2 showed similar distribution curves regardless of the resin shade, with shade A3.5 of Z2 and shade A3 of S2 exhibiting the lowest/highest distributions. Similarly for attenuation coefficient and microhardness, the lowest/highest values were exhibited by shade A3.5 of Z2 and shade A3 of S2. On polymerization shrinkage, no statistically significant differences were observed among the different shades of Z2. Similarly for color change, Z2 specimens exhibited only a slight (DeltaE*=0.5-0.9) color change after immersion in distilled water for 10 days, except for shades A3 and A3.5. Taken together, results of the present study suggested that the degree of polymerization of the tested composite resins was minimally affected by resin shade.

  13. The effect of resin shades on microhardness, polymerization shrinkage, and color change of dental composite resins.

    PubMed

    Jeong, Tae-Sung; Kang, Ho-Seung; Kim, Sung-Ki; Kim, Shin; Kim, Hyung-Il; Kwon, Yong Hoon

    2009-07-01

    The present study sought to evaluate the effect of resin shades on the degree of the polymerization. To this end, response variables affected by the degree of polymerization were examined in this study - namely, microhardness, polymerization shrinkage, and color change. Two commercial composite resins of four different shades were employed in this study: shades A3, A3.5, B3, and C3 of Z250 (Z2) and shades A3, A3.5, B3, and B4 of Solitaire 2 (S2). After light curing, the reflectance/absorbance, microhardness, polymerization shrinkage, and color change of the specimens were measured. On reflectance and absorbance, Z2 and S2 showed similar distribution curves regardless of the resin shade, with shade A3.5 of Z2 and shade A3 of S2 exhibiting the lowest/highest distributions. Similarly for attenuation coefficient and microhardness, the lowest/highest values were exhibited by shade A3.5 of Z2 and shade A3 of S2. On polymerization shrinkage, no statistically significant differences were observed among the different shades of Z2. Similarly for color change, Z2 specimens exhibited only a slight (DeltaE*=0.5-0.9) color change after immersion in distilled water for 10 days, except for shades A3 and A3.5. Taken together, results of the present study suggested that the degree of polymerization of the tested composite resins was minimally affected by resin shade. PMID:19721281

  14. Energy Balance Alterations Due to Cropland Conversion in a Tropical Montane Environment: Shaded Coffee to Sugarcane

    NASA Astrophysics Data System (ADS)

    Alvarado-Barrientos, M. S.; Holwerda, F.; Salazar-Martinez, D.

    2014-12-01

    Although land use change (LUC) is an important driver of changes in climate, very limited field observations of atmosphere-landscape interactions exist in tropical montane zones to examine the extent to which LUCs affect climate locally and regionally. The lack of ground observations hampers the evaluation of satellite-derived datasets of land surface parameters as well as the validation of regional climate models. The first results of an ongoing study of the climate effects of a LUC trajectory in the lower montane region (1200 m a.s.l.) of central Veracruz, Mexico, are presented. The radiation balance, turbulent fluxes and soil heat flux were measured in order to obtain field-derived land surface parameters (albedo and Bowen ratio) of two contrasting land uses: shaded coffee (CO) and sugarcane (SU) plantations. Measurements were conducted on days representing different seasons and crop stages during 2014: cold-dry (January), warm-dry (March) and warm-wet (July). Average noon-time albedo was higher for SU than for CO (0.14 vs. 0.11). Soil heat flux was on average 13% and 12% of net radiation for SU and CO, respectively. Preliminary turbulent flux calculations indicate that noon-time Bowen ratio was higher for sugar cane (range: 1.0-1.5) compared to shaded coffee (range: 0.5-1.0). Seasonal (and crop-stage) changes affected the surface parameters of SU mostly. For example, the SU Bowen ratio increased with decreasing soil moisture, indicating soil moisture limitation for transpiration reducing latent heat flux. In contrast, the shaded coffee Bowen ratio remained relatively constant across measuring periods. The energy balance closure was 80% (pending complete eddy covariance data corrections). These results indicate that the conversion of shaded coffee to sugarcane result in a drier and hotter lower atmosphere. Next steps include examining the implications of these local changes for regional climate, with special attention to cloud formation, using a regional model

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

    PubMed Central

    Valladares, Fernando; Gianoli, Ernesto; Saldaña, Alfredo

    2011-01-01

    Background and Aims 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. Methods 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. Key Results 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 %). Conclusions 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. PMID:21685433

  16. [Effects of shading light quality at seedling stage on the photosynthesis and growth of ginger].

    PubMed

    Zhang, Rui-Hua; Xu, Kun

    2008-03-01

    With different color plastic films as shading materials, this paper studied the effects of shading light quality at seedling stage on the growth and photosynthesis of ginger. The results showed that shading with green or blue film induced the greatest chlorophyll content in ginger leaves, followed by shading with white film, and red film. In parallel, the photosynthetic rate under green film-shading was the highest, being 14.9 micromol x m(-2) x s(-1) in the 4th leaves, which was 5.7%, 10.4%, and 18.3% higher than that under white, red, and blue film-shading, respectively. After removing the films at vigorous growth stage, the photosynthetic rate became larger, and its change pattern in different shading treatments was similar to that at seedling stage. No significant differences in the chlorophyll content of young leaves were observed among the shading treatments, except the low chlorophyll content under red film-shading. In contrast, the chlorophyll content in low position leaves under blue and red film-shading was lower than that under green and white film-shading. In the whole growth period, the plants under blue film-shading were higher in height and with thinner stem and lesser shoot, compared with those shaded with other color films. The fresh mass of root, stem, leaf, and rhizome decreased in the order of green, white, red, and blue film-shading, and the yields at harvesting stage were 57,000, 53,709, 51,487, and 48,712 kg x hm(-2), respectively, illustrating that shading with green film at seedling stage could increase the leaf photosynthesis, plant growth, and yield of ginger.

  17. Attenuation of the jasmonate burst, plant defensive traits, and resistance to specialist monarch caterpillars on shaded common milkweed (Asclepias syriaca).

    PubMed

    Agrawal, Anurag A; Kearney, Emily E; Hastings, Amy P; Ramsey, Trey E

    2012-07-01

    Plant responses to herbivory and light competition are often in opposing directions, posing a potential conflict for plants experiencing both stresses. For sun-adapted species, growing in shade typically makes plants more constitutively susceptible to herbivores via reduced structural and chemical resistance traits. Nonetheless, the impact of light environment on induced resistance has been less well-studied, especially in field experiments that link physiological mechanisms to ecological outcomes. Accordingly, we studied induced resistance of common milkweed (Asclepias syriaca, a sun-adapted plant), and linked hormonal responses, resistance traits, and performance of specialist monarch caterpillars (Danaus plexippus) in varying light environments. In natural populations, plants growing under forest-edge shade showed reduced levels of resistance traits (lower leaf toughness, cardenolides, and trichomes) and enhanced light-capture traits (higher specific leaf area, larger leaves, and lower carbon-to-nitrogen ratio) compared to paired plants in full sun. In a field experiment repeated over two years, only milkweeds growing in full sun exhibited induced resistance to monarchs, whereas plants growing in shade were constitutively more susceptible and did not induce resistance. In a more controlled field experiment, plant hormones were higher in the sun (jasmonic acid, salicylic acid, abscisic acid, indole acidic acid) and were induced by herbivory (jasmonic acid and abscisic acid). In particular, the jasmonate burst following herbivory was halved in plants raised in shaded habitats, and this correspondingly reduced latex induction (but not cardenolide induction). Thus, we provide a mechanistic basis for the attenuation of induced plant resistance in low resource environments. Additionally, there appears to be specificity in these interactions, with light-mediated impacts on jasmonate-induction being stronger for latex exudation than cardenolides.

  18. Attenuation of the jasmonate burst, plant defensive traits, and resistance to specialist monarch caterpillars on shaded common milkweed (Asclepias syriaca).

    PubMed

    Agrawal, Anurag A; Kearney, Emily E; Hastings, Amy P; Ramsey, Trey E

    2012-07-01

    Plant responses to herbivory and light competition are often in opposing directions, posing a potential conflict for plants experiencing both stresses. For sun-adapted species, growing in shade typically makes plants more constitutively susceptible to herbivores via reduced structural and chemical resistance traits. Nonetheless, the impact of light environment on induced resistance has been less well-studied, especially in field experiments that link physiological mechanisms to ecological outcomes. Accordingly, we studied induced resistance of common milkweed (Asclepias syriaca, a sun-adapted plant), and linked hormonal responses, resistance traits, and performance of specialist monarch caterpillars (Danaus plexippus) in varying light environments. In natural populations, plants growing under forest-edge shade showed reduced levels of resistance traits (lower leaf toughness, cardenolides, and trichomes) and enhanced light-capture traits (higher specific leaf area, larger leaves, and lower carbon-to-nitrogen ratio) compared to paired plants in full sun. In a field experiment repeated over two years, only milkweeds growing in full sun exhibited induced resistance to monarchs, whereas plants growing in shade were constitutively more susceptible and did not induce resistance. In a more controlled field experiment, plant hormones were higher in the sun (jasmonic acid, salicylic acid, abscisic acid, indole acidic acid) and were induced by herbivory (jasmonic acid and abscisic acid). In particular, the jasmonate burst following herbivory was halved in plants raised in shaded habitats, and this correspondingly reduced latex induction (but not cardenolide induction). Thus, we provide a mechanistic basis for the attenuation of induced plant resistance in low resource environments. Additionally, there appears to be specificity in these interactions, with light-mediated impacts on jasmonate-induction being stronger for latex exudation than cardenolides. PMID:22661306

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

    PubMed

    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. PMID:27560681

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

    PubMed

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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

  3. A Novel Two-Step Method for Screening Shade Tolerant Mutant Plants via Dwarfism

    PubMed Central

    Li, Wei; Katin-Grazzini, Lorenzo; Krishnan, Sanalkumar; Thammina, Chandra; El-Tanbouly, Rania; Yer, Huseyin; Merewitz, Emily; Guillard, Karl; Inguagiato, John; McAvoy, Richard J.; Liu, Zongrang; Li, Yi

    2016-01-01

    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. PMID:27752260

  4. Shaded relief map of US topography from digital elevations

    USGS Publications Warehouse

    Pike, R.J.; Thelin, G.P.

    1989-01-01

    Much geologic and geophysical information that lies encoded within land surface form can be revealed by image processing large files of digitized elevations in fast machines and mapping the results. This convergence of computers, analytic software, data, and output devices has created exciting opportunities for automating the numerical and spatial study of topography. One recent result is the accompanying shaded relief map of the conterminous 48 states. -from Authors

  5. Which offers more scope to suppress river phytoplankton blooms: reducing nutrient pollution or riparian shading?

    PubMed

    Hutchins, M G; Johnson, A C; Deflandre-Vlandas, A; Comber, S; Posen, P; Boorman, D

    2010-10-01

    River flow and quality data, including chlorophyll-a as a surrogate for river phytoplankton biomass, were collated for the River Ouse catchment in NE England, which according to established criteria is a largely unpolluted network. Against these data, a daily river quality model (QUESTOR) was setup and successfully tested. Following a review, a river quality classification scheme based on phytoplankton biomass was proposed. Based on climate change predictions the model indicated that a shift from present day oligotrophic/mesotrophic conditions to a mesotrophic/eutrophic system could occur by 2080. Management options were evaluated to mitigate against this predicted decline in quality. Reducing nutrient pollution was found to be less effective at suppressing phytoplankton growth than the less costly option of establishing riparian shading. In the Swale tributary, ongoing efforts to reduce phosphorus loads in sewage treatment works will only reduce peak (95th percentile) phytoplankton by 11%, whereas a reduction of 44% is possible if riparian tree cover is also implemented. Likewise, in the Ure, whilst reducing nitrate loads by curtailing agriculture in the headwaters may bring about a 10% reduction, riparian shading would instead reduce levels by 47%. Such modelling studies are somewhat limited by insufficient field data but offer a potentially very valuable tool to assess the most cost-effective methods of tackling effects of eutrophication.

  6. Perception of light source distance from shading patterns.

    PubMed

    Schütt, Heiko H; Baier, Franziska; Fleming, Roland W

    2016-01-01

    Varying the distance of a light source from an object alters both the intensity and spatial distribution of surface shading patterns. We tested whether observers can use such cues to infer light source distance. Participants viewed stereoscopic renderings of rough objects with diffuse and glossy surfaces, which were illuminated by a point source at a range of distances. In one task, they adjusted the position of a small probe dot in three dimensions to report the apparent location of the light in the scene. In a second task, they adjusted the shading on one object (by moving an invisible light source) until it appeared to be illuminated from the same distance as another object. Participants' responses increased linearly with the true light source distance, suggesting that they have clear intuitions about how light source distance affects shading patterns for a variety of different surfaces. However, there were also systematic errors: Subjects overestimated light source distance in the probe adjustment task, and in both experiments, roughness and glossiness affected responses. We find the pattern of results is predicted surprisingly well by a simplistic model based only on the area of the image that exceeds a certain intensity threshold. Thus, although subjects can report light source distance, they may rely on simple--sometimes erroneous--heuristics to do so. PMID:26868887

  7. Perception of light source distance from shading patterns.

    PubMed

    Schütt, Heiko H; Baier, Franziska; Fleming, Roland W

    2016-01-01

    Varying the distance of a light source from an object alters both the intensity and spatial distribution of surface shading patterns. We tested whether observers can use such cues to infer light source distance. Participants viewed stereoscopic renderings of rough objects with diffuse and glossy surfaces, which were illuminated by a point source at a range of distances. In one task, they adjusted the position of a small probe dot in three dimensions to report the apparent location of the light in the scene. In a second task, they adjusted the shading on one object (by moving an invisible light source) until it appeared to be illuminated from the same distance as another object. Participants' responses increased linearly with the true light source distance, suggesting that they have clear intuitions about how light source distance affects shading patterns for a variety of different surfaces. However, there were also systematic errors: Subjects overestimated light source distance in the probe adjustment task, and in both experiments, roughness and glossiness affected responses. We find the pattern of results is predicted surprisingly well by a simplistic model based only on the area of the image that exceeds a certain intensity threshold. Thus, although subjects can report light source distance, they may rely on simple--sometimes erroneous--heuristics to do so.

  8. Shading-based DEM refinement under a comprehensive imaging model

    NASA Astrophysics Data System (ADS)

    Peng, Jianwei; Zhang, Yi; Shan, Jie

    2015-12-01

    This paper introduces an approach to refine coarse digital elevation models (DEMs) based on the shape-from-shading (SfS) technique using a single image. Different from previous studies, this approach is designed for heterogeneous terrain and derived from a comprehensive (extended) imaging model accounting for the combined effect of atmosphere, reflectance, and shading. To solve this intrinsic ill-posed problem, the least squares method and a subsequent optimization procedure are applied in this approach to estimate the shading component, from which the terrain gradient is recovered with a modified optimization method. Integrating the resultant gradients then yields a refined DEM at the same resolution as the input image. The proposed SfS method is evaluated using 30 m Landsat-8 OLI multispectral images and 30 m SRTM DEMs. As demonstrated in this paper, the proposed approach is able to reproduce terrain structures with a higher fidelity; and at medium to large up-scale ratios, can achieve elevation accuracy 20-30% better than the conventional interpolation methods. Further, this property is shown to be stable and independent of topographic complexity. With the ever-increasing public availability of satellite images and DEMs, the developed technique is meaningful for global or local DEM product refinement.

  9. Photosynthetic flexibility in maize exposed to salinity and shade

    PubMed Central

    Sharwood, Robert E.; Sonawane, Balasaheb V.; Ghannoum, Oula

    2014-01-01

    C4 photosynthesis involves a close collaboration of the C3 and C4 metabolic cycles across the mesophyll and bundle-sheath cells. This study investigated the coordination of C4 photosynthesis in maize plants subjected to two salinity (50 and 100mM NaCl) treatments and one shade (20% of full sunlight) treatment. Photosynthetic efficiency was probed by combining leaf gas-exchange measurements with carbon isotope discrimination and assaying the key carboxylases [ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) and phosphoenolpyruvate carboxylase (PEPC)] and decarboxylases [nicotinamide adenine dinucleotide phosphate malic enzyme (NADP-ME) and phosphoenolpyruvate carboxykinase (PEP-CK)] operating in maize leaves. Generally, salinity inhibited plant growth and photosynthesis to a lesser extent than shade. Salinity reduced photosynthesis primarily by reducing stomatal conductance and secondarily by equally reducing Rubisco and PEPC activities; the decarboxylases were inhibited more than the carboxylases. Salinity increased photosynthetic carbon isotope discrimination (Δp) and reduced leaf dry-matter carbon isotope composition (13δ) due to changes in p i/p a (intercellular to ambient CO2 partial pressure), while CO2 leakiness out of the bundle sheath (ϕ) was similar to that in control plants. Acclimation to shade was underpinned by a greater downregulation of PEPC relative to Rubisco activity, and a lesser inhibition of NADP-ME (primary decarboxylase) relative to PEP-CK (secondary decarboxylase). Shade reduced Δp and ɸ without significantly affecting leaf 13δ or p i/p a relative to control plants. Accordingly, shade perturbed the balance between the C3 and C4 cycles during photosynthesis in maize, and demonstrated the flexible partitioning of C4 acid decarboxylation activity between NADP-ME and PEP-CK in response to the environment. This study highlights the need to improve our understanding of the links between leaf 13δ and photosynthetic Δp, and the role

  10. Cloud Shading Effects on Characteristic Boundary-Layer Length Scales

    NASA Astrophysics Data System (ADS)

    Horn, G. L.; Ouwersloot, H. G.; Vilà-Guerau de Arellano, J.; Sikma, M.

    2015-11-01

    We studied the effects of shading by shallow cumulus (shallow Cu) and the subsequent effect of inducing heterogeneous conditions at the surface on boundary-layer characteristics. We placed special emphasis on quantifying the changes in the characteristic length and time scales associated with thermals, shallow Cu and induced thermal circulation structures. A series of systematic numerical experiments, inspired by Amazonian thermodynamic conditions, was performed using a large-eddy simulation model coupled to a land-surface model. We used four different experiments to disentangle the effects of shallow Cu on the surface and the response of clouds to these surface changes. The experiments include a `clear case', `transparent clouds', `shading clouds' and a case with a prescribed uniform domain and reduced surface heat flux. We also performed a sensitivity study on the effect of introducing a weak background flow. Length and time scales were calculated using autocorrelation and two-dimensional spectral analysis, and we found that shading controlled by shallow Cu locally lowers surface temperatures and consequently reduces the sensible and latent heat fluxes, thus inducing spatial and temporal variability in these fluxes. The length scale of this surface heterogeneity is not sufficiently large to generate circulations that are superimposed on the boundary-layer scale, but the heterogeneity does disturb boundary-layer dynamics and generates a flow opposite to the normal thermal circulation. Besides this effect, shallow Cu shading reduces turbulent kinetic energy and lowers the convective velocity scale, thus reducing the mass flux. This hampers the thermal lifetime, resulting in a decrease in the shallow Cu residence time (from 11 to 7 min). This reduction in lifetime, combined with a decrease in mass flux, leads to smaller clouds. This is partially compensated for by a decrease in thermal cell size due to a reduction in turbulent kinetic energy. As a result, inter

  11. The influence of word shading and word length on eye movements during reading.

    PubMed

    Leyland, Louise-Ann; Kirkby, Julie A; Juhasz, Barbara J; Pollatsek, Alexander; Liversedge, Simon P

    2013-01-01

    An interesting issue in reading is how parafoveal information affects saccadic targeting and fixation durations. We investigated the influence of shading selected regions of text on eye movements during reading of long and short words within sentences. A target word, either four- or eight-letters long, was presented in one of four shading conditions: the whole target word shaded; the first half shaded; second half shaded; no shading. There was no evidence of a visually mediated parafoveal-on-foveal effect. Saccadic targeting was modulated by the shading on the first half of the word, such that fixations landed closer to the beginning of the word than in the other three shading conditions. Furthermore, partial word shading, resulting in visual non-uniformity of the target word, produced longer gaze durations than the other conditions. Finally, readers spent more time re-reading target words when they were partially shaded than in the other two conditions. We suggest that our effects are due to targeting of the optimal viewing location and revisits to check words that appear visually unusual. Together, the results indicate robust effects of low-level visual characteristics of the word on oculomotor decisions of where and when to move the eyes during reading.

  12. Effects of water level, shade and time on germination and growth of freshwater marsh plants along a simulated successional gradient

    USGS Publications Warehouse

    Kellogg, C.H.; Bridgham, S.D.; Leicht, S.A.

    2003-01-01

    1. We examined the effect of soil organic content (1.4, 3.6, 7.2% soil C), water level (+2, -1, -4 cm from soil surface) and duration (13 or 33 days) on 10 species that varied in abundance during succession in freshwater marshes. We also determined the effect of shade (0, 40, 80% shade) and soil organic content (1.4 and 7.2% soil C) on germination of six species over 62 days with water 0.5 cm below the soil surface. 2. Water level consistently affected species germination on both dates. Above-ground biomass was generally higher with increasing organic content of soil, but shade had little effect on germination or height. 3 The hydrologic zone in which species were found in the field was a good indicator of the response of germination to hydrology. Both early successional species and species wide-spread across the successional gradient show similar germination on all organic contents, while later successional species appear to germinate best at higher organic contents. 4. Successional changes in soils are capable of affecting plant community development, independent of disturbance.

  13. The effects of drought and shade on the performance, morphology and physiology of Ghanaian tree species.

    PubMed

    Amissah, Lucy; Mohren, Godefridus M J; Kyereh, Boateng; Poorter, Lourens

    2015-01-01

    In tropical forests light and water availability are the most important factors for seedling growth and survival but an increasing frequency of drought may affect tree regeneration. One central question is whether drought and shade have interactive effects on seedling growth and survival. Here, we present results of a greenhouse experiment, in which seedlings of 10 Ghanaian tree species were exposed to combinations of strong seasonal drought (continuous watering versus withholding water for nine weeks) and shade (5% irradiance versus 20% irradiance). We evaluated the effects of drought and shade on seedling survival and growth and plasticity of 11 underlying traits related to biomass allocation, morphology and physiology. Seedling survival under dry conditions was higher in shade than in high light, thus providing support for the "facilitation hypothesis" that shade enhances plant performance through improved microclimatic conditions, and rejecting the trade-off hypothesis that drought should have stronger impact in shade because of reduced root investment. Shaded plants had low biomass fraction in roots, in line with the trade-off hypothesis, but they compensated for this with a higher specific root length (i.e., root length per unit root mass), resulting in a similar root length per plant mass and, hence, similar water uptake capacity as high-light plants. The majority (60%) of traits studied responded independently to drought and shade, indicating that within species shade- and drought tolerances are not in trade-off, but largely uncoupled. When individual species responses were analysed, then for most of the traits only one to three species showed significant interactive effects between drought and shade. The uncoupled response of most species to drought and shade should provide ample opportunity for niche differentiation and species coexistence under a range of water and light conditions. Overall our greenhouse results suggest that, in the absence of root

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

    PubMed Central

    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. PMID:26927428

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

    PubMed

    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.

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

    PubMed

    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. PMID:26927428

  17. The Effects of Drought and Shade on the Performance, Morphology and Physiology of Ghanaian Tree Species

    PubMed Central

    Amissah, Lucy; Mohren, Godefridus M. J.; Kyereh, Boateng; Poorter, Lourens

    2015-01-01

    In tropical forests light and water availability are the most important factors for seedling growth and survival but an increasing frequency of drought may affect tree regeneration. One central question is whether drought and shade have interactive effects on seedling growth and survival. Here, we present results of a greenhouse experiment, in which seedlings of 10 Ghanaian tree species were exposed to combinations of strong seasonal drought (continuous watering versus withholding water for nine weeks) and shade (5% irradiance versus 20% irradiance). We evaluated the effects of drought and shade on seedling survival and growth and plasticity of 11 underlying traits related to biomass allocation, morphology and physiology. Seedling survival under dry conditions was higher in shade than in high light, thus providing support for the “facilitation hypothesis” that shade enhances plant performance through improved microclimatic conditions, and rejecting the trade-off hypothesis that drought should have stronger impact in shade because of reduced root investment. Shaded plants had low biomass fraction in roots, in line with the trade-off hypothesis, but they compensated for this with a higher specific root length (i.e., root length per unit root mass), resulting in a similar root length per plant mass and, hence, similar water uptake capacity as high-light plants. The majority (60%) of traits studied responded independently to drought and shade, indicating that within species shade- and drought tolerances are not in trade-off, but largely uncoupled. When individual species responses were analysed, then for most of the traits only one to three species showed significant interactive effects between drought and shade. The uncoupled response of most species to drought and shade should provide ample opportunity for niche differentiation and species coexistence under a range of water and light conditions. Overall our greenhouse results suggest that, in the absence of root

  18. Esthetic restorative material shade changes due to photopolymerization.

    PubMed

    Watanabe, Hidehiko; Covey, David

    2008-05-01

    This study sought to measure color values (before and after photopolymerization) and variations of A1 shade polymeric dental restorative materials. The L*a*b* values of polymeric dental restorative material disks were measured by a spectrophotometer with the specular component excluded (SCE) geometry under D65 illumination over a standardized white background before and after photopolymerization. Color differences (DeltaE*ab) due to polymerization were calculated using the CIE Lab color-difference formula. DeltaE*ab indicates differences between two colors in the L*a*b* color space. In this system, L*, a*, and b* indicate lightness, red-green, and yellow-blue, respectively. Color differences (DeltaE*ab) were calculated by the equation DeltaE*ab = [(DeltaL*)2 + (Deltaa*)2 + (Deltab*)2]1/2. Eight resin composites, three flowable resin composites (FRCs), and two resin-modified glass ionomers (RMGIs) were utilized; L*a*b* and DeltaE*ab values of the test groups were analyzed using ANOVA and Newman-Keuls multiple comparison tests. DeltaE*ab values before and after photopolymerization ranged from 3.01-17.76. All RMGI and two FRC materials displayed greater color changes than the resin composites (p < 0.05). Photopolymerization produced measurable increases and decreases in lightness. Yellow-blue (b*) values decreased in all test groups after polymerization, while most red-green (a*) values increased. Color differences between polymerized A1 shade materials ranged from 0.76-25.41 DeltaE*ab. The color difference between the test materials and a widely used tooth shade guide (the Vita Lumin) was averaged at 12.66 DeltaE*ab.

  19. Shade Avoidance Components and Pathways in Adult Plants Revealed by Phenotypic Profiling

    PubMed Central

    Nozue, Kazunari; Tat, An V.; Kumar Devisetty, Upendra; Robinson, Matthew; Mumbach, Maxwell R.; Ichihashi, Yasunori; Lekkala, Saradadevi; Maloof, Julin N.

    2015-01-01

    Shade from neighboring plants limits light for photosynthesis; as a consequence, plants have a variety of strategies to avoid canopy shade and compete with their neighbors for light. Collectively the response to foliar shade is called the shade avoidance syndrome (SAS). The SAS includes elongation of a variety of organs, acceleration of flowering time, and additional physiological responses, which are seen throughout the plant life cycle. However, current mechanistic knowledge is mainly limited to shade-induced elongation of seedlings. Here we use phenotypic profiling of seedling, leaf, and flowering time traits to untangle complex SAS networks. We used over-representation analysis (ORA) of shade-responsive genes, combined with previous annotation, to logically select 59 known and candidate novel mutants for phenotyping. Our analysis reveals shared and separate pathways for each shade avoidance response. In particular, auxin pathway components were required for shade avoidance responses in hypocotyl, petiole, and flowering time, whereas jasmonic acid pathway components were only required for petiole and flowering time responses. Our phenotypic profiling allowed discovery of seventeen novel shade avoidance mutants. Our results demonstrate that logical selection of mutants increased success of phenotypic profiling to dissect complex traits and discover novel components. PMID:25874869

  20. Interactions between Auxin, Microtubules and XTHs Mediate Green Shade- Induced Petiole Elongation in Arabidopsis

    PubMed Central

    Sasidharan, Rashmi; Keuskamp, Diederik H.; Kooke, Rik; Voesenek, Laurentius A. C. J.; Pierik, Ronald

    2014-01-01

    Plants are highly attuned to translating environmental changes to appropriate modifications in growth. Such phenotypic plasticity is observed in dense vegetations, where shading by neighboring plants, triggers rapid unidirectional shoot growth (shade avoidance), such as petiole elongation, which is partly under the control of auxin. This growth is fuelled by cellular expansion requiring cell-wall modification by proteins such as xyloglucan endotransglucosylase/hydrolases (XTHs). Cortical microtubules (cMTs) are highly dynamic cytoskeletal structures that are also implicated in growth regulation. The objective of this study was to investigate the tripartite interaction between auxin, cMTs and XTHs in shade avoidance. Our results indicate a role for cMTs to control rapid petiole elongation in Arabidopsis during shade avoidance. Genetic and pharmacological perturbation of cMTs obliterated shade-induced growth and led to a reduction in XTH activity as well. Furthermore, the cMT disruption repressed the shade-induced expression of a specific set of XTHs. These XTHs were also regulated by the hormone auxin, an important regulator of plant developmental plasticity and also of several shade avoidance responses. Accordingly, the effect of cMT disruption on the shade enhanced XTH expression could be rescued by auxin application. Based on the results we hypothesize that cMTs can mediate petiole elongation during shade avoidance by regulating the expression of cell wall modifying proteins via control of auxin distribution. PMID:24594664

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

    SciTech Connect

    Kapsis, K.; Athienitis, A.K.; Zmeureanu, R.G.; Tzempelikos, A.

    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)

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

    SciTech Connect

    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.

  3. Ecophysiological and morphological responses to shade and drought in two contrasting ecotypes of Prunus serotina.

    PubMed

    Abrams, M D; Kloeppel, B D; Kubiske, M E

    1992-06-01

    Photosynthesis (A), water relations and stomatal reactivity during drought, and leaf morphology were evaluated on 2-year-old, sun- and shade-grown Prunus serotina Ehrh. seedlings of a mesic Pennsylvania seed source and a more xeric Wisconsin source. Wisconsin plants maintained higher A and leaf conductance (g(wv)) than Pennsylvania plants during the entire drought under sun conditions, and during the mid stages of drought under shade conditions. Compared to shade plants, sun plants of both sources exhibited a more rapid decrease in A or % A(max) with decreasing leaf water potential (Psi). Tissue water relations parameters were generally not significantly different between seed sources. However, osmotic potentials were lower in sun than shade plants under well-watered conditions. Following drought, shade plants, but not sun plants, exhibited significant osmotic adjustment. Sun leaves had greater thickness, specific mass, area and stomatal density and lower guard cell length than shade leaves in one or both sources. Wisconsin sun leaves were seemingly more xerophytic with greater thickness, specific mass, and guard cell length than Pennsylvania sun leaves. No source differences in leaf structure were exhibited in shade plants. Stomatal reactivity to sun-shade cycles was similar between ecotypes. However, well-watered and droughted plants differed in stomatal reactivity within and between multiple sun-shade cycles. The observed ecotypic and phenotypic variations in ecophysiology and morphology are consistent with the ability of Prunus serotina to survive in greatly contrasting environments. PMID:14969972

  4. 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

    PubMed Central

    Oh, Seon-Hee

    2015-01-01

    PURPOSE 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. MATERIALS AND METHODS 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. RESULTS The effects of zirconia specimen thickness (P<.001), abutment shade (P<.001), and type of zirconia copings (P<.003) on the final shade of the zirconia restorations were significant. The average ΔE value of Lava specimens (1 mm) between the A2 composite resin and gold alloy abutments was higher (close to the acceptability threshold of 5.5 ΔE) than th ose between the A2 composite resin and other abutments. CONCLUSION This in-vitro study demonstrated that abutment shade, ceramic thickness, and coping type affected the resulting shade of zirconia restorations. PMID:26576252

  5. Microclimatological and Physiological Controls of Stomatal Conductance and Transpiration of Co-Occurring Seedlings with Varying Shade Tolerance

    NASA Astrophysics Data System (ADS)

    Siegert, C. M.; Levia, D. F.

    2010-12-01

    Forest ecosystems provide a significant portion of fresh water to the hydrologic cycle through transpiration, the majority of which is supplied by saplings and mature trees. However, a smaller, yet measurable, proportion is also supplied by seedlings. The contribution of seedlings is dependent upon physiological characteristics of the species, whose range of habitat is ultimately controlled by microclimate. The objectives of this study were to (1) observe meteorological conditions of two forest microlimates and (2) assess the intra- and interspecific stomatal conductance and transpiration responses of naturally occurring seedlings of varying shade tolerance. Naturally established seedlings in a deciduous forest understory and an adjacent clearing were monitored throughout the 2008 growing season in southeastern Pennsylvania (39°49'N, 75°43'W). Clear spatial and temporal trends of stomatal conductance and transpiration were observed throughout this study. The understory microclimate conditions overall had a lower degree of variability and had consistently lower mean quantum flux density, air temperature, vapor pressure deficit, volumetric water content, and soil temperature than the clearing plot. Shade tolerant understory seedlings (Fagus grandifolia Ehrh. (American beech) and Prunus serotina L. (black cherry)) had significantly lower mean monthly rates of water loss (p = 0.05) than shade intolerant clearing seedlings (P. serotina and Liriodendron tulipifera L. (yellow poplar)). Additionally, water loss by shade grown P. serotina was significantly lower (p = 0.05) than by sun grown P. serotina. Significant intraspecific responses (p = 0.05) were also observed on a monthly basis, with the exception of L. tulipifera. These findings indicate that physiological differences, specifically shade tolerance, play an important role in determining rates of stomatal conductance and transpiration in tree seedlings. To a lesser degree, microclimate variability was also shown

  6. Riparian shading controls instream spring phytoplankton and benthic algal growth.

    PubMed

    Halliday, S J; Skeffington, R A; Wade, A J; Bowes, M J; Read, D S; Jarvie, H P; Loewenthal, M

    2016-06-15

    Dissolved oxygen (DO) concentrations showed a striking pattern in a multi-year study of the River Enborne, a small river in SE England. In each of three years (2010-2012), maximum DO concentrations were attained in mid-April, preceded by a period of steadily increasing diurnal amplitudes, followed by a steady reduction in both amplitude and concentration. Flow events during the reduction period reduce DO to low concentrations until the following spring. Evidence is presented that this pattern is mainly due to benthic algal growth which is eventually suppressed by the growth of the riparian tree canopy. Nitrate and silicate concentrations are too high to inhibit the growth of either benthic algae or phytoplankton, but phosphate concentrations might have started to reduce growth if the tree canopy development had been delayed. This interpretation is supported by evidence from weekly flow cytometry measurements and analysis of the diurnal, seasonal and annual patterns of nutrient concentrations. As the tree canopy develops, the river switches from an autotrophic to a heterotrophic state. The results support the use of riparian shading to help control algal growth, and highlight the risks of reducing riparian shade.

  7. Riparian shading controls instream spring phytoplankton and benthic algal growth.

    PubMed

    Halliday, S J; Skeffington, R A; Wade, A J; Bowes, M J; Read, D S; Jarvie, H P; Loewenthal, M

    2016-06-15

    Dissolved oxygen (DO) concentrations showed a striking pattern in a multi-year study of the River Enborne, a small river in SE England. In each of three years (2010-2012), maximum DO concentrations were attained in mid-April, preceded by a period of steadily increasing diurnal amplitudes, followed by a steady reduction in both amplitude and concentration. Flow events during the reduction period reduce DO to low concentrations until the following spring. Evidence is presented that this pattern is mainly due to benthic algal growth which is eventually suppressed by the growth of the riparian tree canopy. Nitrate and silicate concentrations are too high to inhibit the growth of either benthic algae or phytoplankton, but phosphate concentrations might have started to reduce growth if the tree canopy development had been delayed. This interpretation is supported by evidence from weekly flow cytometry measurements and analysis of the diurnal, seasonal and annual patterns of nutrient concentrations. As the tree canopy develops, the river switches from an autotrophic to a heterotrophic state. The results support the use of riparian shading to help control algal growth, and highlight the risks of reducing riparian shade. PMID:27192431

  8. Light-Induced Indeterminacy Alters Shade-Avoiding Tomato Leaf Morphology1[OPEN

    PubMed Central

    Chitwood, Daniel H.; Kumar, Ravi; Ranjan, Aashish; Pelletier, Julie M.; Townsley, Brad T.; Ichihashi, Yasunori; Martinez, Ciera C.; Zumstein, Kristina; Harada, John J.; Maloof, Julin N.; Sinha, Neelima R.

    2015-01-01

    Plants sense the foliar shade of competitors and alter their developmental programs through the shade-avoidance response. Internode and petiole elongation, and changes in overall leaf area and leaf mass per area, are the stereotypical architectural responses to foliar shade in the shoot. However, changes in leaf shape and complexity in response to shade remain incompletely, and qualitatively, described. Using a meta-analysis of more than 18,000 previously published leaflet outlines, we demonstrate that shade avoidance alters leaf shape in domesticated tomato (Solanum lycopersicum) and wild relatives. The effects of shade avoidance on leaf shape are subtle with respect to individual traits but are combinatorially strong. We then seek to describe the developmental origins of shade-induced changes in leaf shape by swapping plants between light treatments. Leaf size is light responsive late into development, but patterning events, such as stomatal index, are irrevocably specified earlier. Observing that shade induces increases in shoot apical meristem size, we then describe gene expression changes in early leaf primordia and the meristem using laser microdissection. We find that in leaf primordia, shade avoidance is not mediated through canonical pathways described in mature organs but rather through the expression of KNOTTED1-LIKE HOMEOBOX and other indeterminacy genes, altering known developmental pathways responsible for patterning leaf shape. We also demonstrate that shade-induced changes in leaf primordium gene expression largely do not overlap with those found in successively initiated leaf primordia, providing evidence against classic hypotheses that shaded leaf morphology results from the prolonged production of juvenile leaf types. PMID:26381315

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

    PubMed

    Sefcik, Lesley T; Zak, Donald R; Ellsworth, David S

    2006-12-01

    Seedling responses to elevated atmospheric CO(2) concentration ([CO(2)]) and solar irradiance were measured over two growing seasons in shade-tolerant Acer saccharum Marsh. and Fagus grandifolia J.F. Ehrh. and shade-intolerant Prunus serotina, a J.F. Ehrh. and Betula papyrifera Marsh. Seedlings were exposed to a factorial combination of [CO2] (ambient and elevated (658 micromol mol-1)) and understory shade (deep and moderate) in open-top chambers placed in a forest understory. The elevated [CO(2)] treatment increased mean light-saturated net photosynthetic rate by 63% in the shade-tolerant species and 67% in the shade-intolerant species. However, when measured at the elevated [CO(2)], long-term enhancement of photosynthesis was 10% lower than the instantaneous enhancement seen in ambient-[CO(2)]-grown plants (P < 0.021). Overall, growth light environment affected long-term photosynthetic enhancement by elevated [CO(2)]: as the growth irradiance increased, proportional enhancement due to elevated [CO(2)] decreased from 97% for plants grown in deep shade to 47% for plants grown in moderate shade. Results suggest that in 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, because of greater downregulation in the latter environment. If photosynthetic gains by deep-shade-grown plants in response to elevated [CO(2)] translate into improved growth and survival of shade-intolerant species, it could alter the future composition and dynamics of successional forest communities. PMID:17169898

  10. Automated analysis of hypocotyl growth dynamics during shade avoidance in Arabidopsis.

    PubMed

    Cole, Benjamin; Kay, Steve A; Chory, Joanne

    2011-03-01

    Plants that are adapted to environments where light is abundant are especially sensitive to competition for light from neighboring vegetation. As a result, these plants initiate a series of changes known as the shade avoidance syndrome, during which plants elongate their stems and petioles at the expense of leaf development. Although the developmental outcomes of exposure to prolonged shade are known, the signaling dynamics during the initial exposure of seedlings to shade is less well studied. Here, we report the development of a new software-based tool, called HyDE (Hypocotyl Determining Engine) to measure hypocotyl lengths of time-resolved image stacks of Arabidopsis wild-type and mutant seedlings. We show that Arabidopsis grows rapidly in response to the shade stimulus, with measurable growth after just 45 min shade exposure. Similar to other mustard species, this growth response occurs in multiple distinct phases, including two phases of rapid growth and one phase of slower growth. Using mutants affected in shade avoidance phenotypes, we demonstrate that most of this early growth requires new auxin biosynthesis via the indole-3-pyruvate pathway. When activity of this pathway is reduced, the first phase of elongation growth is absent, and this is correlated with reduced activity of auxin-regulated genes. Finally, we show that varying shade intensity and duration can affect the shape and magnitude of the growth response, indicating a broad range of the elongation response to shade.

  11. Shades of Pink: Preschoolers Make Meaning in a Reggio-Inspired Classroom

    ERIC Educational Resources Information Center

    Kim, Bo Sun

    2012-01-01

    Shades of Pink study describes how six preschoolers and their teacher engaged in a collaborative learning project through which they learned about the shades of a color--in this case, pink. As the children learned through experimenting and discussing their theories, they represented ideas using art as a tool for discovery and learning. The study…

  12. A novel high-throughput in vivo molecular screen for shade

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The shade avoidance syndrome (SAS) allows plants to anticipate and avoid shading by neighbouring plants by initiating an elongation growth response. The phytochrome photoreceptors are able to detect a reduction in the red:far red ratio in incident light, the result of selective absorption of red and...

  13. The Stevens-Levolor Environmental Simulator and the study of interior shading for energy efficient windows

    NASA Astrophysics Data System (ADS)

    Vandyck, R. L.; Konen, T. P.

    A window systems and experiments in a unique environmental simulator with an artificial sun were tested. It is shown that interior venetian blind shading is an effective window energy management technique. Predictive methods of generating shading coefficients applicable to modern venetian blinds is confirmed. The findings indicating light colored, as well as highly reflective blinds yielded as significant energy savings.

  14. The effects of zilpaterol hydrochloride and shade on blood metabolites of finishing beef steers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of feeding zilpaterol hydrochloride (ZH) and shade were evaluated on blood metabolites and lung score in finishing beef steers. Cattle were fed 0 or 8.33 mg/kg ZH for 21 d with a 3- or 4-d withdrawal before harvest and were housed in open or shaded pens. Blood samples and lung scores w...

  15. Effects of shade on the development and sugar metabolism of coffee (Coffea arabica L.) fruits.

    PubMed

    Geromel, Clara; Ferreira, Lúcia Pires; Davrieux, Fabrice; Guyot, Bernard; Ribeyre, Fabienne; Brígida dos Santos Scholz, Maria; Protasio Pereira, Luiz Filipe; Vaast, Philippe; Pot, David; Leroy, Thierry; Androcioli Filho, Armando; Esteves Vieira, Luiz Gonzaga; Mazzafera, Paulo; Marraccini, Pierre

    2008-01-01

    Coffee fruits grown in shade are characterized by larger bean size than those grown under full-sun conditions. The present study assessed the effects of shade on bean characteristics and sugar metabolism by analyzing tissue development, sugar contents, activities of sucrose metabolizing enzymes and expression of sucrose synthase-encoding genes in fruits of coffee (Coffea arabica L.) plants submitted to full-sun (FS) and shade (SH) conditions. Evolution of tissue fresh weights measured in fruits collected regularly from flowering to maturation indicated that this increase is due to greater development of the perisperm tissue in the shade. The effects of light regime on sucrose and reducing sugar (glucose and fructose) contents were studied in fresh and dry coffee beans. Shade led to a significant reduction in sucrose content and to an increase in reducing sugars. In pericarp and perisperm tissues, higher activities of sucrose synthase (EC 2.4.1.13) and sucrose-phosphate synthase (SPS: EC 2.4.1.14) were detected at maturation in the shade compared with full sun. These two enzymes also had higher peaks of activities in developing endosperm under shade than in full sun. It was also noted that shade modified the expression of SUS-encoding genes in coffee beans; CaSUS2 gene transcripts levels were higher in SH than in FS. As no sucrose increase accompanied these changes, this suggests that sucrose metabolism was redirected to other metabolic pathways that need to be identified.

  16. Sediment and water-quality data for the West Branch Shade and East Branch Shade River basins, Ohio, 1983 water year

    USGS Publications Warehouse

    Childress, C.J.; Jones, R.L.

    1985-01-01

    Sedimentation in and flooding of the West Branch Shade River and its tributaries have been major concerns of residents and State and local officials. The area was extensively surface mined for coal between the mid-1940's and the early 1960's. Reclamation efforts immediately after mining were unsuccessful. The results have been elevated sediment loads and the subsequent loss of channel conveyance. Two sediment and stream-gaging stations were established on the West Branch Shade River and one station was established on the East Branch Shade River. These three stations will provide data to evalute the effectiveness of current reclamation activties on reducing sediment loads. From June Through September 1983, suspended-sediment yield was 18 times higher in West Branch (218 tons/mi2) than East Branch (12 tons/mi2) Shade River. In addition, acidity is higher, pH is lower, and concentrations of dissolved sulfate and metals are higher in the West Branch Shade River basin than in the East Branch Shade river basins.

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

    NASA Astrophysics Data System (ADS)

    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 (P<0.01) than the average BGT recorded outside: 35.5 (SD 1.12)°C. Average BGTs in holding pens were 32.4 (SD 1.38) and 39.9 (SD 1.91)°C for shaded and non-shaded areas (P<0.01). The corresponding average floor temperatures were 27.8 (SD 0.68)°C and 47.7 (SD 2.13)°C (P<0.01). To assess the effects of shade on animal well-being, afternoon rectal temperatures (RT) and respiratory rate (respirations per minute, RR) of lactating cows were recorded twice a week. Rectal temperatures were significantly higher for non-shaded cows (P<0.01), mean RT being 40.1 (SD 0.65)°C vs 39.3 (SD 0.42)°C for the shaded animals. Corresponding RRs were 78.9 (SD 18.0) and 60.7 (SD 10.6) (P<0.05). It was concluded that: (1) tree 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.

  18. Design of a radiator shade for testing in a simulated lunar environment

    NASA Technical Reports Server (NTRS)

    Huff, Jaimi; Remington, Randy; Tang, Toan

    1992-01-01

    The National Aeronautics and Space Administration (NASA) and The Universities Space Research Association (USRA) have chosen the parabolic/catenary concept from their sponsored Fall 1991 lunar radiation shade project for further testing and development. NASA asked the design team to build a shading device and support structure for testing in a vacuum chamber. Besides the support structure for the catenary shading device, the design team was asked to develop a system for varying the shade shape so that the device can be tested at different focal lengths. The design team developed concept variants and combined the concept variants to form overall designs. Using a decision matrix, an overall design was selected by the team from several overall design alternatives. Concept variants were developed for three primary functions. The three functions were structural support, shape adjustments, and end shielding. The shade adjustment function was divided into two sub-functions, arc length adjustment, and width adjustment.

  19. Native bees mediate long-distance pollen dispersal in a shade coffee landscape mosaic.

    PubMed

    Jha, Shalene; Dick, Christopher W

    2010-08-01

    Coffee farms are often embedded within a mosaic of agriculture and forest fragments in the world's most biologically diverse tropical regions. Although shade coffee farms can potentially support native pollinator communities, the degree to which these pollinators facilitate gene flow for native trees is unknown. We examined the role of native bees as vectors of gene flow for a reproductively specialized native tree, Miconia affinis, in a shade coffee and remnant forest landscape mosaic. We demonstrate extensive cross-habitat gene flow by native bees, with pollination events spanning more than 1,800 m. Pollen was carried twice as far within shade coffee habitat as in nearby forest, and trees growing within shade coffee farms received pollen from a far greater number of sires than trees within remnant forest. The study shows that shade coffee habitats support specialized native pollinators that enhance the fecundity and genetic diversity of remnant native trees.

  20. [Effects of color films shading on Phellodendron amurense seedlings biomass and primary nitrogen-assimilation enzyme activities].

    PubMed

    Li, Xia; Yan, Xiufeng; Yu, Tao

    2006-11-01

    In this paper, greenhouse Phellodendron amurense seedlings were shaded with red, yellow, blue, and green films for 100 days, and their biomass, chlorophyll and soluble protein contents, and nitrate reductase and glutamine synthetase activities were determined. Compared with exposure under sunlight, color films shading decreased the seedlings biomass significantly. Plant height and stem diameter had the similar trend with plant biomass. Root/ shoot ratio was less affected by red and yellow films shading, while root biomass was decreased significantly under blue and green films shading. Leaf chlorophyll content was increased significantly under the shading with blue, green and red films, especially with blue film. Red film shading increased the chlorophyll a/b ratio, while blue film shading was in adverse. Under color films shading, soluble protein content and nitrate reductase and glutamine synthetase activities were significantly higher than the control.

  1. Shaded Relief with Color as Height, St. Louis, Missouri

    NASA Technical Reports Server (NTRS)

    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

  2. Mts. Agung and Batur, Bali, Shaded Relief and Colored Height

    NASA Technical Reports Server (NTRS)

    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

  3. Shaded Relief Image of Saint Pierre and Miquelon

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This image shows two islands, Miquelon and Saint Pierre, located south of Newfoundland, Canada. These islands, along with five smaller islands, are a self-governing territory of France. A thin barrier beach divides Miquelon, with Grande Miquelon to the north and Petite Miquelonto the south. Saint Pierre Island is located to the lower right. With the islandsi location in the north Atlantic Ocean and their deep water ports, fishing is the major part of the economy. The maximum elevation of the island is 240 meters (787 feet). The land mass of the islands is about 242 square kilometers, or 1.5 times the size of Washington DC.

    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.

    This image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard the Space Shuttle Endeavour, launched on February 11, 2000. SRTM 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, installed additional C-band and X-band antennas, and improved tracking and navigation devices. The mission is a cooperative project between the National Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense (DoD), and the German and Italian space agencies. It is managed by NASAis Jet Propulsion

  4. SRTM Colored Height and Shaded Relief: Lava plateaus in Argentina

    NASA Technical Reports Server (NTRS)

    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

  5. Shenandoah National Park, Virginia, Shaded Relief with Height as Color

    NASA Technical Reports Server (NTRS)

    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

  6. World in Mercator Projection, Shaded Relief and Colored Height

    NASA Technical Reports Server (NTRS)

    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

  7. Shaded Relief of South Africa, Northern Cape Province

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Located north of the Swartberg Mountains in South Africa's Northern Cape Province, this topographic image shows a portion of the Great Karoo region. Karoo is an indigenous word for 'dry thirst land.' The semi-arid area is known for its unique variety of flora and fauna. The topography of the area, with a total relief of 200 meters (650 feet), reveals much about the geologic history of the area. The linear features seen in the image are near-vertical walls of once-molten rock, or dikes, that have intruded the bedrock. The dikes are more resistant to weathering and, therefore, form the linear wall-like features seen in the image. In relatively flat arid areas such as this, small changes in the topography can have large impacts on the water resources and the local ecosystem. These data can be used by biologists to study the distribution and range of the different plants and animals. Geologists can also use the data to study the geologic history of this area in more detail.

    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

  8. Potential energy savings with exterior shades in large office buildings and the impact of discomfort glare

    SciTech Connect

    Hoffmann, Sabine; Lee, Eleanor

    2015-04-01

    Exterior shades are highly efficient for reducing solar load in commercial buildings. Their impact on net energy use depends on the annual energy balance of heating, cooling, fan and lighting energy. This paper discusses the overall energy use intensity of various external shading systems for a prototypical large office building split into the different types of energy use and for different orientations and window sizes. Lighting energy was calculated for a constant lighting power as well as for dimmed lighting fixtures (daylighting control). In Section 3, slat angles and solar cut-off angles were varied for fixed exterior slat shading systems. While the most light-blocking shades performed best for the case without daylighting controls, the optimum cut-off angle with daylighting controls was found to be 30 deg for the office building prototype used in Chicago and Houston. For large window-to-wall (WWR) ratios, window related annual energy use could be reduced by at least 70 % without daylighting control and by a minimum of 86 % with daylighting control in average over all orientations. The occurrence of discomfort glare was is considered in Section 4 of the paper, which looks at the performance of commercially available exterior shading systems when an interior shade is used in addition to the exterior shade during hours when occupants would experience discomfort glare. Glare control impacts overall energy use intensity significantly for exterior shades with high transmittance, especially when daylighting controls are used. In these cases, exterior shades are only beneficial for window-to-wall areas ≥ 45% in the hot Houston climate. For smaller windows and in a heating/cooling climate like Chicago, exterior shades can increase energy consumption

  9. Acclimation of leaves to contrasting irradiance in juvenile trees differing in shade tolerance.

    PubMed

    Wyka, Tomasz; Robakowski, Piotr; Zytkowiak, Roma

    2007-09-01

    Leaves developing in different irradiances undergo structural and functional acclimation, although the extent of trait plasticity is species specific. We tested the hypothesis that irradiance-induced plasticity of photosynthetic and anatomical traits is lower in highly shade-tolerant species than in moderately shade-tolerant species. Seedlings of two evergreen conifers, shade-tolerant Abies alba Mill. and moderately shade-tolerant Picea abies Karst., and two deciduous angiosperm species, highly shade-tolerant Fagus sylvatica L. and moderately shade-tolerant Acer pseudoplatanus L., were grown in deep shade (LL, 5% of full irradiance) or in full solar irradiance (HL) during 2003 and 2004. Steady state responses of quantum yield of PSII (Phi(PSII)), apparent electron transport rate (ETR), nonphotochemical quenching (NPQ) and photochemical quenching (qP) were generally modified by the light environment, with slower declines in Phi(PSII) and qP and greater maximal ETR and NPQ values in HL plants in at least one season; however, no link between quantitative measures of plasticity of these traits and shade tolerance was found. Plasticity of nine anatomical traits (including palisade cell length, which was reduced in LL) showed no relationship with shade tolerance, but was less in conifers than in deciduous trees, suggesting that leaf life span may be a significant correlate of plasticity. When LL-acclimated plants were exposed to HL conditions, the degree and duration of photoinhibition (measured as a decline in maximum quantum yield) was greatest in F. sylvatica, much lower in P. abies and A. alba, and lowest in A. pseudoplatanus. Thus, as with the other traits studied, vulnerability to photoinhibition showed no relationship with shade tolerance.

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

    USGS Publications Warehouse

    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.

  11. Characterization of a type II chlorophyll a/b-binding protein gene (Lhcb2*Pp1) in peach. II. mRNA abundance in developing leaves exposed to sun or shade.

    PubMed

    Bassett, Carole L; Callahan, Ann M

    2003-05-01

    Leaf development of shoots exposed to full sunlight and shoots shaded by the canopy was followed in field-grown, mature peach trees (Prunus persica (L.) Batsch, cv. Loring) during the first half of the 1995 growing season. The architecture and size of shaded shoots and sun-exposed shoots differed significantly. Total number of leaves produced on shaded shoots was significantly less than on sun-exposed shoots throughout the season, and differences in leaf number between light conditions increased as the season progressed. The overall patterns of leaf development along sun-exposed and shaded shoots were qualitatively similar. The expression pattern of the type II chlorophyll a/b-binding protein gene, Lhcb2*Pp1, determined by RNA abundance in leaves at different positions along the shoot, was also similar between the two light conditions. The major difference between sun-exposed and shaded leaves was a lower abundance of Lhcb2*Pp1 RNA in mature, shaded leaves compared with sun-exposed leaves. Although the number of fruit per shoot was significantly lower on shaded shoots than on sun-exposed shoots, the rate of fruit drop was not substantially different during the growing season, indicating that quantitative differences in leaf initiation and growth caused by differences in light exposure did not adversely affect fruit retention. However, based on comparison with a previous study of leaf development in non-fruiting trees, reproductive development slowed the rate of vegetative growth without affecting the overall pattern of leaf development along the shoots. PMID:12670801

  12. Mt. Elgon, Africa, Shaded Relief and Colored Height

    NASA Technical Reports Server (NTRS)

    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

  13. Shaded Relief with Height as Color, Yucatan Peninsula, Mexico

    NASA Technical Reports Server (NTRS)

    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

  14. Landsat - SRTM Shaded Relief Comparison, Los Angeles and Vicinity

    NASA Technical Reports Server (NTRS)

    2002-01-01

    Digital elevation models (DEMs), such as those produced by the Shuttle Radar Topography Mission (SRTM), allow user-controlled visualization of the Earth's landforms that is not possible using satellite imagery alone. This three-view comparison shows Los Angeles, Calif., and vicinity, with a Landsat image (only) on the left, a shaded relief rendering of the SRTM DEM on the right, and a merge of the two data sets in the middle. Note that topographic expression in the Landsat image alone is very subtle due to the fairly high sun angle (63 degrees above the horizon) during the satellite overflight in late morning of a mid-Spring day (May 4, 2001). In contrast, computer generated topographic shading of the DEM provides a pure and bold image of topographic expression with a user specified illumination direction. The middle image shows how combining the Landsat and DEM shaded relief can result in a topographically enhanced satellite image in which the information content of both data sets is merged into a single view.

    Landsat has been providing visible and infrared views of the Earth since 1972. SRTM elevation data matches the 30-meter (98-foot) resolution of most Landsat images and helps in analyzing the large and growing Landsat image archive, managed by the U.S. Geological Survey (USGS).

    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

  15. Shaded Relief Mosaic of Umnak Island, Aleutian Islands, Alaska

    NASA Technical Reports Server (NTRS)

    2001-01-01

    This image is a shaded relief mosaic of Umnak Island in Alaska's Aleutian Islands.

    It was created with Airsar data that was geocoded and combined into this mosaic as part of a NASA-funded Alaska Digital Elevation Model Project at the Alaska Synthetic Aperture Radar Facility (ASF) at the University of Alaska Geophysical Institute in Fairbanks, Alaska.

    Airsar collected the Alaska data as part of its PacRim 2000 Mission, which took the instrument to French Polynesia, American and Western Samoa, Fiji, New Zealand, Australia, New Guinea, Indonesia, Malaysia, Cambodia, Philippines, Taiwan, South Korea, Japan, Northern Marianas, Guam, Palau, Hawaii and Alaska. Airsar, part of NASA's Airborne Science Program, is managed for NASA's Earth Science Enterprise by JPL. JPL is a division of the California Institute of Technology in Pasadena.

  16. Preference of domestic horses for shade in a hot, sunny environment.

    PubMed

    Holcomb, K E; Tucker, C B; Stull, C L

    2014-04-01

    Provision of shade is recommended by best practice guidelines for horses living in hot, sunny environments despite a lack of research focused on potential benefits. We found in a previous study that horses without access to shade showed greater rectal temperature (RT), respiration rate (RR), and skin temperature (SK) and exhibited more sweat than horses that were completely shaded. Yet not known is whether horses will choose to stand in the shade when given a choice of areas with and without this resource. Our objective was to assess horse preference for shaded and unshaded areas in the hot and arid, sunny summer weather in Davis, California. For this preference test, 12 healthy, adult horses (6 mares, 6 geldings) were randomized into 3 sequential trials using 4 horses in each trial. The trials consisted of 2 d of acclimation and either 5 d (Trial 1) or 7 d (Trials 2 and 3) of observation. Horses were housed individually in dry lot pens. Half of each pen was covered by an open-sided shade structure. The amount of the pen shaded varied slightly throughout the day with a mean of 50.1% of the pen shaded. Physiological measurements (RT, RR, SK, sweat score) were recorded at 0900, 1230, and 1800 h. Behavioral observations (horses' location relative to shade, time spent walking, foraging, and standing) were recorded at 5-min intervals from 1300 to 1800 h daily and at 10-min intervals from 1800 to 1300 h on alternate days. Insect avoidance behavior was recorded for 1 min/h for each horse. Weather factors were recorded every 5 min, 24 h/d throughout the study; mean daytime ambient temperature was 29 °C ± 5 °C. Data were analyzed using PROC MIXED in SAS. Horses were located in the shade in 7.1% more observations than by chance (SE = 1.3, P < 0.001), with greatest use before and during peak solar radiation and then again following peak black globe temperature. Horses performed more walking and foraging behavior in the shaded areas (P < 0.01). Our research indicates that

  17. Metabolomic analysis using ultra-performance liquid chromatography-quadrupole-time of flight mass spectrometry (UPLC-Q-TOF MS) uncovers the effects of light intensity and temperature under shading treatments on the metabolites in tea.

    PubMed

    Zhang, Qunfeng; Shi, Yuanzhi; Ma, Lifeng; Yi, Xiaoyun; Ruan, Jianyun

    2014-01-01

    To investigate the effect of light intensity and temperature on the biosynthesis and accumulation of quality-related metabolites, field grown tea plants were shaded by Black Net and Nano-insulating Film (with additional 2-4°C cooling effect) with un-shaded plants as a control. Young shoots were subjected to UPLC-Q-TOF MS followed by multivariate statistical analysis. Most flavonoid metabolites (mainly flavan-3-ols, flavonols and their glycosides) decreased significantly in the shading treatments, while the contents of chlorophyll, β-carotene, neoxanthin and free amino acids, caffeine, benzoic acid derivatives and phenylpropanoids increased. Comparison between two shading treatments indicated that the lower temperature under Nano shading decreased flavonols and their glycosides but increased accumulation of flavan-3-ols and proanthocyanidins. The comparison also showed a greater effect of temperature on galloylation of catechins than light intensity. Taken together, there might be competition for substrates between the up- and down-stream branches of the phenylpropanoid/flavonoid pathway, which was influenced by light intensity and temperature. PMID:25390340

  18. Metabolomic analysis using ultra-performance liquid chromatography-quadrupole-time of flight mass spectrometry (UPLC-Q-TOF MS) uncovers the effects of light intensity and temperature under shading treatments on the metabolites in tea.

    PubMed

    Zhang, Qunfeng; Shi, Yuanzhi; Ma, Lifeng; Yi, Xiaoyun; Ruan, Jianyun

    2014-01-01

    To investigate the effect of light intensity and temperature on the biosynthesis and accumulation of quality-related metabolites, field grown tea plants were shaded by Black Net and Nano-insulating Film (with additional 2-4°C cooling effect) with un-shaded plants as a control. Young shoots were subjected to UPLC-Q-TOF MS followed by multivariate statistical analysis. Most flavonoid metabolites (mainly flavan-3-ols, flavonols and their glycosides) decreased significantly in the shading treatments, while the contents of chlorophyll, β-carotene, neoxanthin and free amino acids, caffeine, benzoic acid derivatives and phenylpropanoids increased. Comparison between two shading treatments indicated that the lower temperature under Nano shading decreased flavonols and their glycosides but increased accumulation of flavan-3-ols and proanthocyanidins. The comparison also showed a greater effect of temperature on galloylation of catechins than light intensity. Taken together, there might be competition for substrates between the up- and down-stream branches of the phenylpropanoid/flavonoid pathway, which was influenced by light intensity and temperature.

  19. Hypothenemus hampei (Coleoptera: Curculionidae) and its interactions with Azteca instabilis and Pheidole synanthropica (Hymenoptera: Formicidae) in a shade coffee agroecosystem.

    PubMed

    Jiménez-Soto, Estelí; Cruz-Rodríguez, Juan A; Vandermeer, John; Perfecto, Ivette

    2013-10-01

    The coffee berry borer is currently the most important insect pest of coffee worldwide. In shaded coffee farms such as Finca Irlanda in Chiapas, Mexico, natural enemies limit coffee berry borer and potentially prevent outbreaks. This research aimed to determine the effect of ants on coffee berry borer damage and to describe behaviors of Azteca instabilis F. Smith and Pheidole synanthropica (Longino 2009) when encountering the coffee berry borer. To these ends, an ant survey was conducted in a 2,500-m(2) plot within the farm. A 4- by 4-m coordinate system was established, and the coffee plant or shade tree closest to the coordinate point was sampled using tuna fish for a total of 168 coffee plants and 46 shade trees sampled. In addition, up to 100 berries were harvested from 138 coffee plants to measure damage and verify the presence of the coffee berry borer. Behavior was determined in the field by placing live coffee berry borer adults on berries and video recording all attacks. Results showed that plants with ants had less percentage of damaged berries and shorter coffee berry borer galleries than plants without ants. However, the length of galleries in plants with A. instabilis showed no significant differences from plants without ants. P. synanthropica was observed carrying coffee berry borer to the nest in 50% of the cases, whereas A. instabilis threw coffee berry borer off of the coffee plant in 79% of the cases. Results indicate that the presence of these species of ants reduce coffee berry borer damage and suggest that different behaviors could explain the pattern of coffee berry borer attack in this agroecosystem. PMID:24331603

  20. Are sun- and shade-type anatomy required for the acclimation of Neoregelia cruenta?

    PubMed

    Reinert, Fernanda; Leal-Costa, Marcos V; Junqueira, Nícia E; Tavares, Eliana S

    2013-01-01

    Sun and shade plants are often discriminated by a number of sun- and shade-type anatomies. Nonetheless, we propose that among tank-bromeliads, changes in rosette architecture satisfy the requirements for coping with contrasting light levels. The tank-bromeliad Neoregelia cruenta naturally colonises sub-habitats ranging from full exposure to direct sunlight, to shaded environments in sand ridge plains. We quantified anatomical and morphological traits of leaves and rosettes of N. cruenta grown under sun and shade conditions. Cells with undulated lateral walls within the water parenchyma are for the first time described for the family. Under high light, leaf blades were wider, shorter, and yellowish. The rosette diameter of sun plants was less than half that of shade plants. Sun leaves overlapped with neighbouring leaves for most of their length, forming a cylindrical rosette where water accumulates. Shade leaves only overlapped in the centre of the rosette. Most anatomical traits were similar under both growth conditions. Stomata were absent from the base of sun leaves, which is probably explained by limited gas exchange at the base of the tight sun-type rosette. Data suggest that the ability of N. cruenta to acclimate to sun and shade is better explained by changes in rosette architecture than by leaf anatomy.

  1. Adolescents’ use of purpose built shade in secondary schools: cluster randomised controlled trial

    PubMed Central

    White, Vanessa; Wakefield, Melanie A; Jamsen, Kris M; White, Victoria; Livingston, Patricia M; English, Dallas R; Simpson, Julie A

    2009-01-01

    Objective To examine whether students use or avoid newly shaded areas created by shade sails installed at schools. Design Cluster randomised controlled trial with secondary schools as the unit of randomisation. Setting 51 secondary schools with limited available shade, in Australia, assessed over two spring and summer terms. Participants Students outside at lunch times. Intervention Purpose built shade sails were installed in winter 2005 at full sun study sites to increase available shade for students in the school grounds. Main outcome measure Mean number of students using the primary study sites during weekly observations at lunch time. Results Over the study period the mean change in students using the primary study site from pre-test to post-test was 2.63 (95% confidence interval 0.87 to 4.39) students in intervention schools and −0.03 (−1.16 to 1.09) students in control schools. The difference in mean change between groups was 2.67 (0.65 to 4.68) students (P=0.011). Conclusions Students used rather than avoided newly shaded areas provided by purpose built shade sails at secondary schools in this trial, suggesting a practical means of reducing adolescents’ exposure to ultraviolet radiation. Trial registration Exempt. PMID:19223344

  2. An Appraisal of the Classic Forest Succession Paradigm with the Shade Tolerance Index

    PubMed Central

    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. PMID:25658092

  3. Are sun- and shade-type anatomy required for the acclimation of Neoregelia cruenta?

    PubMed

    Reinert, Fernanda; Leal-Costa, Marcos V; Junqueira, Nícia E; Tavares, Eliana S

    2013-01-01

    Sun and shade plants are often discriminated by a number of sun- and shade-type anatomies. Nonetheless, we propose that among tank-bromeliads, changes in rosette architecture satisfy the requirements for coping with contrasting light levels. The tank-bromeliad Neoregelia cruenta naturally colonises sub-habitats ranging from full exposure to direct sunlight, to shaded environments in sand ridge plains. We quantified anatomical and morphological traits of leaves and rosettes of N. cruenta grown under sun and shade conditions. Cells with undulated lateral walls within the water parenchyma are for the first time described for the family. Under high light, leaf blades were wider, shorter, and yellowish. The rosette diameter of sun plants was less than half that of shade plants. Sun leaves overlapped with neighbouring leaves for most of their length, forming a cylindrical rosette where water accumulates. Shade leaves only overlapped in the centre of the rosette. Most anatomical traits were similar under both growth conditions. Stomata were absent from the base of sun leaves, which is probably explained by limited gas exchange at the base of the tight sun-type rosette. Data suggest that the ability of N. cruenta to acclimate to sun and shade is better explained by changes in rosette architecture than by leaf anatomy. PMID:23828343

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

    PubMed

    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.

  5. Spectrophotometric Study of the Effect of Luting Agents on the Resultant Shade of Ceramic Veneers: An Invitro Study

    PubMed Central

    Kale, Yogesh; Pustake, Swati; Bijjaragi, Shobha; Pustake, Bhushan

    2015-01-01

    Introduction Dentistry has found practically the best available aesthetic answer, is ceramic restoration. There are various factors that contribute to the success of ceramic veneers, like colour of underlying tooth, thickness if ceramics and the type of underlying luting cement. Shade selection and matching remains still challenge, however the shade of luting agent used for cementation of veneers produces a change in resultant shade of veneers. Aim To compare and analyze the spectrophotometric effect of opaque and transparent luting agent on resultant shade of ceramic veneers made of 2L1.5 shade (Vitapan 3D-Masters) and B2 shade (Vitapan Classic). Materials and Methods Out of 15 ceramic veneers of 2L1.5 shade (VITAPAN 3D- Master), seven teeth cemented with opaque cement and eight teeth with transparent cement shade of dual cure resin cement (Variolink IITM). Out of 10 ceramic veneers of B2 shade (VITAPAN Classic), five teeth were cemented with opaque cement and other five teeth with transparent cement shade of dual cure resin cement (Variolink IITM). Spectrophotometric (Macbeth U.S.A.) analysis of all ceramic veneer crowns done with optiview software and readings were recorded in Commission Internationale de I’ Eclairge {CIELAB} system and dE value was calculated. Statistical Analysis Statistical analysis was done by using Paired t-test. Results Spectrophotometric analysis of all the veneers cemented with opaque luting agent were lighter in shade due to significant change in dL value. Veneers cemented with transparent luting agent were darker in shade due to significant change in the dL value. Conclusion Opaque luting agent gives lighter shade and transparent luting agent gives darker shade to ceramic veneers fabricated with 2L1.5 and B2 shades. PMID:26501014

  6. Seeing the landscape for the trees: Metrics to guide riparian shade management in river catchments

    NASA Astrophysics Data System (ADS)

    Johnson, Matthew F.; Wilby, Robert L.

    2015-05-01

    Rising water temperature (Tw) due to anthropogenic climate change may have serious consequences for river ecosystems. Conservation and/or expansion of riparian shade could counter warming and buy time for ecosystems to adapt. However, sensitivity of river reaches to direct solar radiation is highly heterogeneous in space and time, so benefits of shading are also expected to be site specific. We use a network of high-resolution temperature measurements from two upland rivers in the UK, in conjunction with topographic shade modeling, to assess the relative significance of landscape and riparian shade to the thermal behavior of river reaches. Trees occupy 7% of the study catchments (comparable with the UK national average) yet shade covers 52% of the area and is concentrated along river corridors. Riparian shade is most beneficial for managing Tw at distances 5-20 km downstream from the source of the rivers where discharge is modest, flow is dominated by near-surface hydrological pathways, there is a wide floodplain with little landscape shade, and where cumulative solar exposure times are sufficient to affect Tw. For the rivers studied, we find that approximately 0.5 km of complete shade is necessary to off-set Tw by 1°C during July (the month with peak Tw) at a headwater site; whereas 1.1 km of shade is required 25 km downstream. Further research is needed to assess the integrated effect of future changes in air temperature, sunshine duration, direct solar radiation, and downward diffuse radiation on Tw to help tree planting schemes achieve intended outcomes.

  7. Influence of resin cement shade on the color and translucency of ceramic veneers

    PubMed Central

    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

  8. Ontogeny, understorey light interception and simulated carbon gain of juvenile rainforest evergreens differing in shade tolerance

    PubMed Central

    Lusk, Christopher H.; Pérez-Millaqueo, Manuel Matías; Piper, Frida I.; Saldaña, Alfredo

    2011-01-01

    Background and Aims A long-running debate centres on whether shade tolerance of tree seedlings is mainly a function of traits maximizing net carbon gain in low light, or of traits minimizing carbon loss. To test these alternatives, leaf display, light-interception efficiency, and simulated net daily carbon gain of juvenile temperate evergreens of differing shade tolerance were measured, and how these variables are influenced by ontogeny was queried. Methods The biomass distribution of juveniles (17–740 mm tall) of seven temperate rainforest evergreens growing in low (approx. 4 %) light in the understorey of a second-growth stand was quantified. Daytime and night-time gas exchange rates of leaves were also determined, and crown architecture was recorded digitally. YPLANT was used to model light interception and carbon gain. Results An index of species shade tolerance correlated closely with photosynthetic capacities and respiration rates per unit mass of leaves, but only weakly with respiration per unit area. Accumulation of many leaf cohorts by shade-tolerant species meant that their ratios of foliage area to biomass (LAR) decreased more gradually with ontogeny than those of light-demanders, but also increased self-shading; this depressed the foliage silhouette-to-area ratio (STAR), which was used as an index of light-interception efficiency. As a result, displayed leaf area ratio (LARd = LAR × STAR) of large seedlings was not related to species shade tolerance. Self-shading also caused simulated net daily carbon assimilation rates of shade-tolerant species to decrease with ontogeny, leading to a negative correlation of shade tolerance with net daily carbon gain of large (500 mm tall) seedlings in the understorey. Conclusions The results suggest that efficiency of energy capture is not an important correlate of shade tolerance in temperate rainforest evergreens. Ontogenetic increases in self-shading largely nullify the potential carbon gain advantages expected

  9. Effect of time and weather on preference, frequency, and duration of shade use by horses.

    PubMed

    Holcomb, K E; Stull, C L

    2016-04-01

    The Federation of Animal Science Societies (FASS) recommends providing access to shade for horses in hot, sunny weather at equine facilities. Previously, we found that healthy, mature domestic horses use shade with behavioral and physiological benefits during those weather conditions. The objective of this study was to characterize preference, frequency, and duration of shade use by healthy, mature horses in a Bureau of Land Management (BLM) holding facility during hot, sunny weather. The study took place at the BLM's Palomino Valley Wild Horse and Burro Center in Reno, NV, from Aug. 10 to Oct. 1, 2014. Freestanding shade structures were constructed in each of 2 drylot pens with shade cloth covering the top that blocked 98% of UV radiation. A group of 4 mares was placed in each of the 2 pens. After a 2-d acclimation period, data were recorded for 5 d, the horses were moved to the opposite pen, and data collected for an additional 5 d. This schedule was repeated for a total of 4 consecutive trials and 32 horses. Footage from time-lapse cameras was viewed at 10 s intervals between 0930 and 1700 h to record each horse's position relative to shade. Dosimeters secured to horses' halters recorded UV exposure. Automated weather stations recorded daytime ambient temperature (mean 25.9°C [SD 5.8]), relative humidity (mean 25.4% [SD 17.1]), black globe temperature (mean 29.3°C [SD 6.5] in shade and 35.8°C [SD 8.0] in unshaded area), and solar radiation (mean 595 W/m [SD 235]). Horses spent 10.9% more time in shade than by chance ( < 0.0001) within the drylots across all 40 study days. Mean daily time spent in shade was 107.9 min/horse (SD 66.9), comprising 17.1 bouts (SD 12.1) with an average bout length of 6.3 min (SD 3.4). The mean daily UV Index experienced by horses in these partially shaded drylots was 1.52 (SD 0.58) compared with 3.4 (SD 1.5) for a control instrument in the sun. Horses used shade more on the sunniest days and greater than just by chance at all hours

  10. Effect of time and weather on preference, frequency, and duration of shade use by horses.

    PubMed

    Holcomb, K E; Stull, C L

    2016-04-01

    The Federation of Animal Science Societies (FASS) recommends providing access to shade for horses in hot, sunny weather at equine facilities. Previously, we found that healthy, mature domestic horses use shade with behavioral and physiological benefits during those weather conditions. The objective of this study was to characterize preference, frequency, and duration of shade use by healthy, mature horses in a Bureau of Land Management (BLM) holding facility during hot, sunny weather. The study took place at the BLM's Palomino Valley Wild Horse and Burro Center in Reno, NV, from Aug. 10 to Oct. 1, 2014. Freestanding shade structures were constructed in each of 2 drylot pens with shade cloth covering the top that blocked 98% of UV radiation. A group of 4 mares was placed in each of the 2 pens. After a 2-d acclimation period, data were recorded for 5 d, the horses were moved to the opposite pen, and data collected for an additional 5 d. This schedule was repeated for a total of 4 consecutive trials and 32 horses. Footage from time-lapse cameras was viewed at 10 s intervals between 0930 and 1700 h to record each horse's position relative to shade. Dosimeters secured to horses' halters recorded UV exposure. Automated weather stations recorded daytime ambient temperature (mean 25.9°C [SD 5.8]), relative humidity (mean 25.4% [SD 17.1]), black globe temperature (mean 29.3°C [SD 6.5] in shade and 35.8°C [SD 8.0] in unshaded area), and solar radiation (mean 595 W/m [SD 235]). Horses spent 10.9% more time in shade than by chance ( < 0.0001) within the drylots across all 40 study days. Mean daily time spent in shade was 107.9 min/horse (SD 66.9), comprising 17.1 bouts (SD 12.1) with an average bout length of 6.3 min (SD 3.4). The mean daily UV Index experienced by horses in these partially shaded drylots was 1.52 (SD 0.58) compared with 3.4 (SD 1.5) for a control instrument in the sun. Horses used shade more on the sunniest days and greater than just by chance at all hours

  11. Pando Province, Northern Bolivia, Shaded Relief and Colored Height

    NASA Technical Reports Server (NTRS)

    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

  12. SRTM Colored Height and Shaded Relief: Pinon Canyon region, Colorado

    NASA Technical Reports Server (NTRS)

    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

  13. Shaded Relief with Height as Color, Iturralde Structure, Bolivia

    NASA Technical Reports Server (NTRS)

    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

  14. The dynamical influences of cloud shading on simulated supercell thunderstorms

    NASA Astrophysics Data System (ADS)

    Frame, Jeffrey

    2008-10-01

    Numerical simulations of supercell thunderstorms which include parameterized radiative transfer and surface fluxes are performed using the Advanced Regional Prediction System (ARPS) model. The tilted independent column approximation (TICA) is adopted for use in the ARPS model because the existing method of parameterized radiative transfer, the independent column approximation (ICA), permits only the vertical transfer of shortwave radiation. The computed radiative fluxes from both the TICA and ICA are compared to output from a three-dimensional Monte Carlo radiative transfer solver and it is determined that the TICA fluxes more closely match those from the Monte Carlo model than do those from the ICA. Additionally, the TICA is able to capture the extensions of shadows that occur when the solar zenith angle deviates significantly from zero, which cannot be captured by the ICA. The maximum low-level air temperature deficits within the modeled cloud shadows is 1.5 to 2.0 K, which is only about half that previously observed. The loss of strong solar heating of the model surface within the shaded regions cools the surface temperatures, and changes the sign of the sensible heat flux near the edge of the shadow. This stabilizes the model surface layer and suppresses vertical mixing at low levels within the shaded area. This reduction in vertical mixing means that higher momentum air from aloft is prevented from mixing with air near the surface that has lost momentum to surface friction. The net result of this is a shallower, but more intense vertically-sheared layer near the surface. As the supercell's rear-flank gust front propagates into this modified shear layer, the layer of cold outflow air becomes shallower and it accelerates eastward. In the case of a stationary storm, the cold outflow undercuts the updraft and mesocyclone, depriving them of warm and moist inflow, and ultimately weakening the storm. These results are not likely applicable to all simulations of

  15. Cuttlefish see shape from shading, fine-tuning coloration in response to pictorial depth cues and directional illumination.

    PubMed

    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. PMID:26984626

  16. A scaleable methodology for assessing the impacts of urban shade on the summer electricity use of residential homes

    NASA Astrophysics Data System (ADS)

    Taylor, Robert Vanderlei

    Our cities are experiencing unprecedented growth while net global temperatures continue to trend warmer making sustainable urban development and energy conservation pressing public issues. This research explores how urban landscaping -- in particular trees and buildings -- affect summer electricity use in residential homes. I studied the interactions of urban shade and temperature to explore how vegetation distribution and intensity could play a meaningful role in heat mitigation in urban environments. Only a few studies have reconciled modeled electricity savings from tree shade with actual electricity consumption data. This research proposes a methodology for modeling the isolated effects of urban shade (tree shade vs building shade) on buildings' summertime electricity consumption from micro to mesoscales, empirically validating the modeled shade with actual electricity billing data, and comparing the electric energetic impact of tree shade effects with building shade effects. This proposed methodology seeks to resolve three primary research questions: 1) What are the modeled quantities of urban shade associated with the area of interest (AOI)? 2) To what extent do the effects of shading from trees and buildings mitigate summertime heat in the AOI? 2) To what extent do the shade effects from trees and buildings reduce summertime electricity consumption in the AOI?

  17. Shaded Relief with Height as Color, Mount Meru, Tanzania

    NASA Technical Reports Server (NTRS)

    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

  18. San Gabriel Mountains, California, Shaded relief, color as height

    NASA Technical Reports Server (NTRS)

    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

  19. Perspective View with Color-Coded Shaded Relief, Central Panama

    NASA Technical Reports Server (NTRS)

    2002-01-01

    This perspective view shows central Panama, with the remnants of the extinct volcano El Valle in the foreground and the Caribbean Sea in the distance. El Valle underwent an explosive eruption about 3 million years ago, forming a crater 5 kilometers (3.1 miles) across, one of the largest in the Americas. The crater subsequently filled with water forming a huge lake, but about 12,000 years ago a breach at the present site of the waterfall Choro de las Mozas caused it to drain, forming the present valley. Within the crater is the town of El Valle de Anton, whose 600-meter (1,968-foot) elevation and resulting cooler climate make it a popular tourist and vacation site.

    The lake in the distance is Lake Gatun, at the west end of the Panama Canal. The canal itself extends to the southwest (to the right in this northeast facing view) but is hidden by the intervening terrain.

    This shaded relief perspective view was generated using topographic data from the Shuttle Radar Topography Mission (SRTM). 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, and range from green at the lowest elevations to white at the highest elevations.

    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 and improved tracking and navigation devices. The mission is a cooperative project between NASA, the National Imagery and Mapping Agency (NIMA) and the

  20. Accuracy of shade matching performed by colour blind and normal dental students using 3D Master and Vita Lumin shade guides.

    PubMed

    Vafaee, F; Rakhshan, V; Vafaei, M; Khoshhal, M

    2012-03-01

    The purpose of this study was to investigate whether 3D Master or VitaLumin shade guides could improve colour selection in individuals with normal and defective colour vision. First, colour perception of 260 dental students was evaluated. Afterwards, 9 colour blind and 9 matched normal subjects tried to detect colours of 10 randomly selected tabs from each kit and the correct/false answers were counted. Of the colour-defective subjects, 47.8% and 33.3% correctly detected the shade using 3D Master and VitaLumin, respectively. These statistics were 62.2% and 42.2% in normal subjects. In normal participants, but not in colour blind ones, 3D Master significantly improved shade matching accuracy compared to VitaLumin.

  1. Continuous shading and its fast update in fully analytic triangular-mesh-based computer generated hologram.

    PubMed

    Park, Jae-Hyeung; Kim, Seong-Bok; Yeom, Han-Ju; Kim, Hee-Jae; Zhang, HuiJun; Li, BoNi; Ji, Yeong-Min; Kim, Sang-Hoo; Ko, Seok-Bum

    2015-12-28

    Fully analytic mesh-based computer generated hologram enables efficient and precise representation of three-dimensional scene. Conventional method assigns uniform amplitude inside individual mesh, resulting in reconstruction of the three-dimensional scene of flat shading. In this paper, we report an extension of the conventional method to achieve the continuous shading where the amplitude in each mesh is continuously varying. The proposed method enables the continuous shading, while maintaining fully analytic framework of the conventional method without any sacrifice in the precision. The proposed method can also be extended to enable fast update of the shading for different illumination directions and the ambient-diffuse reflection ratio based on Phong reflection model. The feasibility of the proposed method is confirmed by the numerical and optical reconstruction of the generated hologram.

  2. Ornamental and Shade Tree Pest Control: A Guide for Commercial Applicators.

    ERIC Educational Resources Information Center

    Khan, M. S.

    This is a training manual for commercial pesticide applicators. It gives information for identification and control of diseases, insects, mites, weeds, and vertebrate pests of shade and ornamental trees. Phytotoxicity, environmental concerns, and pesticide application information is also given. (BB)

  3. Interactions between carbon sequestration and shade tree diversity in a smallholder coffee cooperative in El Salvador.

    PubMed

    Richards, Meryl Breton; Méndez, V Ernesto

    2014-04-01

    Agroforestry systems have substantial potential to conserve native biodiversity and provide ecosystem services. In particular, agroforestry systems have the potential to conserve native tree diversity and sequester carbon for climate change mitigation. However, little research has been conducted on the temporal stability of species diversity and aboveground carbon stocks in these systems or the relation between species diversity and aboveground carbon sequestration. We measured changes in shade-tree diversity and shade-tree carbon stocks in 14 plots of a 35-ha coffee cooperative over 9 years and analyzed relations between species diversity and carbon sequestration. Carbon sequestration was positively correlated with initial species richness of shade trees. Species diversity of shade trees did not change significantly over the study period, but carbon stocks increased due to tree growth. Our results show a potential for carbon sequestration and long-term biodiversity conservation in smallholder coffee agroforestry systems and illustrate the opportunity for synergies between biodiversity conservation and climate change mitigation.

  4. Daylight Adaptive Shading Using Parametric Camshaft Mechanism for SOHO in Jakarta

    NASA Astrophysics Data System (ADS)

    Utama Sjarifudin, Firza; Justina, Laurensia

    2014-03-01

    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°.

  5. The Art of Being Flexible: How to Escape from Shade, Salt, and Drought1

    PubMed Central

    Pierik, Ronald; Testerink, Christa

    2014-01-01

    Environmental stresses, such as shading of the shoot, drought, and soil salinity, threaten plant growth, yield, and survival. Plants can alleviate the impact of these stresses through various modes of phenotypic plasticity, such as shade avoidance and halotropism. Here, we review the current state of knowledge regarding the mechanisms that control plant developmental responses to shade, salt, and drought stress. We discuss plant hormones and cellular signaling pathways that control shoot branching and elongation responses to shade and root architecture modulation in response to drought and salinity. Because belowground stresses also result in aboveground changes and vice versa, we then outline how a wider palette of plant phenotypic traits is affected by the individual stresses. Consequently, we argue for a research agenda that integrates multiple plant organs, responses, and stresses. This will generate the scientific understanding needed for future crop improvement programs aiming at crops that can maintain yields under variable and suboptimal conditions. PMID:24972713

  6. Determination of the usage of shade structures via a dosimetry technique.

    PubMed

    Parisi, Alfio V; Eley, Robert; Downs, Nathan

    2012-01-01

    A measurement system is described that allows an objective review and evaluation of the amount of use by different population groups of provided shade structures. It employs the comparison of the erythemal UV exposure measured with dosimeters to either the vertex or forehead to that in full sun. The technique has been developed using three shade structures and found to provide a linear relationship with an R(2) of 0.99 between the exposure ratio and the time spent in the shade for the solar zenith angle range of 19-53° and for both low- and high-cloud levels. It provides an objective determination of the amount of shade use by population groups that have set periods of time outdoors. PMID:22332953

  7. Phytochrome A Mediates the Promotion of Seed Germination by Very Low Fluences of Light and Canopy Shade Light in Arabidopsis.

    PubMed Central

    Botto, J. F.; Sanchez, R. A.; Whitelam, G. C.; Casal, J. J.

    1996-01-01

    Seeds of the wild type (WT) and of the phyA and phyB mutants of Arabidopsis thaliana were exposed to single red light (R)/far-red light (FR) pulses predicted to establish a series of calculated phytochrome photoequilibria (Pfr/P). WT and phyB seeds showed biphasic responses to Pfr/P. The first phase, i.e. the very-low-fluence response (VLFR), occurred below Pfr/P = 10-1%. The second phase, i.e. the low-fluence response, occurred above Pfr/P = 3%. The VLFR was similarly induced by either a FR pulse saturating photoconversion or a subsaturating R pulse predicted to establish the same Pfr/P. The VLFR was absent in phyA seeds, which showed a strong low-fluence response. In the field, even brief exposures to the very low fluences of canopy shade light (R/FR ratio < 0.05) promoted germination above dark controls in WT and phyB seeds but not in the phyA mutant. Seeds of the phyA mutant germinated normally under canopies providing higher R/FR ratios or under deep canopy shade light supplemented with R from light-emitting diodes. We propose that phytochrome A mediates VLFR of A. thaliana seeds. PMID:12226195

  8. Microleakage in class V gingiva-shaded composite resin restorations

    PubMed Central

    Poggio, Claudio; Chiesa, Marco; Dagna, Alberto; Colombo, Marco; Scribante, Andrea

    2012-01-01

    Summary The purpose of this study was to evaluate the microleakage in Class V cavities restored with a new gingiva-shaded microhybrid composite resin and with a conventional microhybrid composite resin using three different dentin bonding systems (DBS). Class V cavities were prepared in sixty freshly extracted human teeth with the incisal margin in enamel and the apical margin in dentin/cementum. Restored specimens, after thermocycling, were placed in 2% methylene blue solution for 24 hours. Longitudinal sections were obtained and studied with a stereomicroscope for assessment of the microleakage according to degree of dye penetration (scale 0–3). Data were analyzed with Kruskal-Wallis test and with Mann-Whitney U-test. In this study there was no leakage in enamel: all the cavities showed no dye penetration at the incisal margins (located in enamel). None of the DBS used eliminated microleakage in apical margins (located in dentin or cementum): three-step total-etch and single-step self-etch were more effective in reducing microleakage in dentin margins when compared with two-step total-etch. This in vitro study concluded that microleakage in Class V cavities restored with the composite resins tested is similar. PMID:22783451

  9. [Effects of shade-humid environment on the growth characteristics of different maize (Zea mays) hybrids].

    PubMed

    Yan, Qing-Jiu; Huo, Shi-Ping; Zhang, Fang-Kui; Zhang, Xing-Duan; Zhang, Jian; Xiang, Zhen-Fan; Yu, Zhi-Jiang; Feng, Yun-Chao

    2013-12-01

    The growth traits of 18 maize hybrids were studied in natural and artificial simulation shade-humid environments. Significant differences were observed between the natural and shade-humid environments, and the air relative humidity in the shade-humid environment increased 15.0%-16.4%, the soil moisture increased 27.0%-78.4%, the illumination intensity decreased 72.9%-77.9%, and the quantum decreased 72.8%-79.6%. Shade did not affect the ambient temperature. The 7th leaf width, effective functional leaves, plant total leaves, tassel branch number, stem diameter, plant height, ear height, ear length, ear diameter, rows per ear, kernels per row, 100-grain mass and grain yield per plant under the shade-humid environment showed negative variations (reduction in phenotypic values), with the grain yield per plant and plant height being reduced by 72.3% and 7.1% respectively, and the declining changes of the remaining traits ranging from 14.8%-53.8%. However, the 7th leaf length, 7th leaf length-width ratio, anthesis to silking (ASI) duration, southern leaf blight (SLB) index and sheath blight index showed positive variations (increase in phenotypic values), with increases by 39.8%, 80.5%, 114.3%, 73.0% and 54.8%, respectively. The comprehensive shade-humid-tolerant coefficient calculated from the seven traits of ASI, tassel branches, plant total leaves, plant height, individual grain yield, southern leaf blight and sheath blight index could be easily and reliably used to evaluate the shade-humid-tolerant ability of the maize hybrids. According to this coefficient, the 18 hybrids could be classified into three categories, strongly-resistant, moderately-resistant and weakly-resistant to the shade-humid environment.

  10. Is Shade Beneficial for Mediterranean Shrubs Experiencing Periods of Extreme Drought and Late-winter Frosts?

    PubMed Central

    Valladares, Fernando; Zaragoza-Castells, Joana; Sánchez-Gómez, David; Matesanz, Silvia; Alonso, Beatriz; Portsmuth, Angelika; Delgado, Antonio; Atkin, Owen K.

    2008-01-01

    Background and Aims 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. Methods 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. Key Results 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. Conclusions 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. PMID:18819947

  11. Photovoltaic Shading Testbed for Module-Level Power Electronics: 2014 Update

    SciTech Connect

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

    2014-08-01

    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.

  12. Simulated herbivory does not constrain phenotypic plasticity to shade through ontogeny in a relict tree.

    PubMed

    Pardo, A; García, F M; Valladares, F; Pulido, F

    2016-07-01

    Ecological limits to phenotypic plasticity (PP), induced by simultaneous biotic and abiotic factors, can prevent organisms from exhibiting optimal plasticity, and in turn lead to decreased fitness. Herbivory is an important biotic stressor and may limit plant functional responses to challenging environmental conditions such as shading. In this study we investigated whether plant functional responses and PP to shade are constrained by herbivory, and whether such constraints are due to direct effects based on resource limitation by considering ontogeny. We used as a model system the relict tree Prunus lusitanica and implemented an indoor experiment to quantify the response of saplings of different ages to shade and herbivory. We measured five functional traits and quantitatively calculated PP. Results showed that herbivory did not constrain functional responses or PP to shade except for shoot:root ratio (SR), which, despite showing a high PP in damaged saplings, decreased under shade instead of increasing. Damaged saplings of older age did not exhibit reduced constraints on functional responses to shade and generally presented a lower PP than damaged saplings of younger age. Our findings suggest that herbivory-mediated constraints on plant plasticity to shade may not be as widespread as previously thought. Nonetheless, the negative effect of herbivory on SR plastic expression to shade could be detrimental for plant fitness. Finally, our results suggest a secondary role of direct effects (resource-based) on P. lusitanica plasticity limitation. Further studies should quantify plant resources in order to gain a better understanding of this seldom-explored subject.

  13. Seasonal contrasts in the response of coffee ants to agroforestry shade-tree management.

    PubMed

    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.

  14. Seasonal contrasts in the response of coffee ants to agroforestry shade-tree management.

    PubMed

    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. PMID:22182538

  15. The impact of light intensity on shade-induced leaf senescence.

    PubMed

    Brouwer, Bastiaan; Ziolkowska, Agnieszka; Bagard, Matthieu; Keech, Olivier; Gardeström, Per

    2012-06-01

    Plants often have to cope with altered light conditions, which in leaves induce various physiological responses ranging from photosynthetic acclimation to leaf senescence. However, our knowledge of the regulatory pathways by which shade and darkness induce leaf senescence remains incomplete. To determine to what extent reduced light intensities regulate the induction of leaf senescence, we performed a functional comparison between Arabidopsis leaves subjected to a range of shading treatments. Individually covered leaves, which remained attached to the plant, were compared with respect to chlorophyll, protein, histology, expression of senescence-associated genes, capacity for photosynthesis and respiration, and light compensation point (LCP). Mild shading induced photosynthetic acclimation and resource partitioning, which, together with a decreased respiration, lowered the LCP. Leaf senescence was induced only under strong shade, coinciding with a negative carbon balance and independent of the red/far-red ratio. Interestingly, while senescence was significantly delayed at very low light compared with darkness, phytochrome A mutant plants showed enhanced chlorophyll degradation under all shading treatments except complete darkness. Taken together, our results suggest that the induction of leaf senescence during shading depends on the efficiency of carbon fixation, which in turn appears to be modulated via light receptors such as phytochrome A.

  16. Sedimentation and water quality in the West Branch Shade River basin, Ohio, 1984 water year

    USGS Publications Warehouse

    Childress, C.J.; Jones, R.L.

    1985-01-01

    Sedimentation in, and flooding of, the West Branch Shade River and its tributaries have been major concerns of residents and State and local officials. The area was extensively surface mined for coal between the mid-1940 's and the early 1960's. Reclamation efforts immediately after mining were unsuccessful. The results have been elevated sediment loads and the subsequent loss of channel conveyance. Two sediment and stream gaging stations were established on West Branch Shade River in the area of past mining to provide data to evaluate the effectiveness of current reclamation activities on reducing sediment loads. A third station was established on the East Branch Shade River in an unmined area as a control. From October 1983 through September 1984, the annual suspended sediment yield/acre-ft of runoff was approximately two times as high for West Branch Shade River (0.51 ton/acre-ft of runoff) as for East Branch Shade River (0.28 ton/acre-ft). In addition, water quality of West Branch indicates that acidity is higher, pH is lower, and concentrations of dissolved sulfate and metals are higher than for East Branch. The concentration of coal in bed material increased in the downstream direction along West Branch Shade River. The concentration downstream in the West Branch was more than 20 times greater than in the East Branch. (Author 's abstract)

  17. Karrikins delay soybean seed germination by mediating abscisic acid and gibberellin biogenesis under shaded conditions

    PubMed Central

    Meng, Yongjie; Chen, Feng; Shuai, Haiwei; Luo, Xiaofeng; Ding, Jun; Tang, Shengwen; Xu, Shuanshuan; Liu, Jianwei; Liu, Weiguo; Du, Junbo; Liu, Jiang; Yang, Feng; Sun, Xin; Yong, Taiwen; Wang, Xiaochun; Feng, Yuqi; Shu, Kai; Yang, Wenyu

    2016-01-01

    Karrikins (KAR) are a class of signal compounds, discovered in wildfire smoke, which affect seed germination. Currently, numerous studies have focused on the model plant Arabidopsis in the KAR research field, rather than on crops. Thus the regulatory mechanisms underlying KAR regulation of crop seed germination are largely unknown. Here, we report that KAR delayed soybean seed germination through enhancing abscisic acid (ABA) biosynthesis, while impairing gibberellin (GA) biogenesis. Interestingly, KAR only retarded soybean seed germination under shaded conditions, rather than under dark and white light conditions, which differs from in Arabidopsis. Phytohormone quantification showed that KAR enhanced ABA biogenesis while impairing GA biosynthesis during the seed imbibition process, and subsequently, the ratio of active GA4 to ABA was significantly reduced. Further qRT-PCR analysis showed that the transcription pattern of genes involved in ABA and GA metabolic pathways are consistent with the hormonal measurements. Finally, fluridone, an ABA biogenesis inhibitor, remarkably rescued the delayed-germination phenotype of KAR-treatment; and paclobutrazol, a GA biosynthesis inhibitor, inhibited soybean seed germination. Taken together, these evidences suggest that KAR inhibit soybean seed germination by mediating the ratio between GA and ABA biogenesis. PMID:26902640

  18. Karrikins delay soybean seed germination by mediating abscisic acid and gibberellin biogenesis under shaded conditions.

    PubMed

    Meng, Yongjie; Chen, Feng; Shuai, Haiwei; Luo, Xiaofeng; Ding, Jun; Tang, Shengwen; Xu, Shuanshuan; Liu, Jianwei; Liu, Weiguo; Du, Junbo; Liu, Jiang; Yang, Feng; Sun, Xin; Yong, Taiwen; Wang, Xiaochun; Feng, Yuqi; Shu, Kai; Yang, Wenyu

    2016-01-01

    Karrikins (KAR) are a class of signal compounds, discovered in wildfire smoke, which affect seed germination. Currently, numerous studies have focused on the model plant Arabidopsis in the KAR research field, rather than on crops. Thus the regulatory mechanisms underlying KAR regulation of crop seed germination are largely unknown. Here, we report that KAR delayed soybean seed germination through enhancing abscisic acid (ABA) biosynthesis, while impairing gibberellin (GA) biogenesis. Interestingly, KAR only retarded soybean seed germination under shaded conditions, rather than under dark and white light conditions, which differs from in Arabidopsis. Phytohormone quantification showed that KAR enhanced ABA biogenesis while impairing GA biosynthesis during the seed imbibition process, and subsequently, the ratio of active GA4 to ABA was significantly reduced. Further qRT-PCR analysis showed that the transcription pattern of genes involved in ABA and GA metabolic pathways are consistent with the hormonal measurements. Finally, fluridone, an ABA biogenesis inhibitor, remarkably rescued the delayed-germination phenotype of KAR-treatment; and paclobutrazol, a GA biosynthesis inhibitor, inhibited soybean seed germination. Taken together, these evidences suggest that KAR inhibit soybean seed germination by mediating the ratio between GA and ABA biogenesis.

  19. Color Shaded-Relief and Surface-Classification Maps of the Fish Creek Area, Harrison Bay Quadrangle, Northern Alaska

    USGS Publications Warehouse

    Mars, John L.; Garrity, Christopher P.; Houseknecht, David W.; Amoroso, Lee; Meares, Donald C.

    2007-01-01

    Introduction The northeastern part of the National Petroleum Reserve in Alaska (NPRA) has become an area of active petroleum exploration during the past five years. Recent leasing and exploration drilling in the NPRA requires the U.S. Bureau of Land Management (BLM) to manage and monitor a variety of surface activities that include seismic surveying, exploration drilling, oil-field development drilling, construction of oil-production facilities, and construction of pipelines and access roads. BLM evaluates a variety of permit applications, environmental impact studies, and other documents that require rapid compilation and analysis of data pertaining to surface and subsurface geology, hydrology, and biology. In addition, BLM must monitor these activities and assess their impacts on the natural environment. Timely and accurate completion of these land-management tasks requires elevation, hydrologic, geologic, petroleum-activity, and cadastral data, all integrated in digital formats at a higher resolution than is currently available in nondigital (paper) formats. To support these land-management tasks, a series of maps was generated from remotely sensed data in an area of high petroleum-industry activity (fig. 1). The maps cover an area from approximately latitude 70?00' N. to 70?30' N. and from longitude 151?00' W. to 153?10' W. The area includes the Alpine oil field in the east, the Husky Inigok exploration well (site of a landing strip) in the west, many of the exploration wells drilled in NPRA since 2000, and the route of a proposed pipeline to carry oil from discovery wells in NPRA to the Alpine oil field. This map area is referred to as the 'Fish Creek area' after a creek that flows through the region. The map series includes (1) a color shaded-relief map based on 5-m-resolution data (sheet 1), (2) a surface-classification map based on 30-m-resolution data (sheet 2), and (3) a 5-m-resolution shaded relief-surface classification map that combines the shaded

  20. Shaded Relief with Height as Color, North America

    NASA Technical Reports Server (NTRS)

    2003-01-01

    , and 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

  1. Climate-change refugia: shading reef corals by turbidity.

    PubMed

    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 <250 μmol m(-2)  s(-1) , and predict that 16% of reef-coral habitat ≤30 m will preclude coral growth and reef development. Thus, protecting the 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. PMID:26695523

  2. Correlation between grain orientation and the shade of color etching

    SciTech Connect

    Szabo, Peter J.; Kardos, I.

    2010-08-15

    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 < 100> direction, while such correlation was not observed between the color parameters and the < 110 > and < 111> directions, respectively. This indicates that film thickness is sensitive to the < 100> direction of the crystal.

  3. Utilising shade to optimize UV exposure for vitamin D

    NASA Astrophysics Data System (ADS)

    Turnbull, D. J.; Parisi, A. V.

    2008-01-01

    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 diffuse UV exposures of 1/6 and 1/3 MED, solar zenith angles smaller than 60° and 50° respectively 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 (290-330 nm) radiation without experiencing the high levels of damaging UVA observed in full sun.

  4. Utilising shade to optimize UV exposure for vitamin D

    NASA Astrophysics Data System (ADS)

    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.

  5. Climate-change refugia: shading reef corals by turbidity.

    PubMed

    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 <250 μmol m(-2)  s(-1) , and predict that 16% of reef-coral habitat ≤30 m will preclude coral growth and reef development. Thus, protecting the 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.

  6. Africa in SRTM 3-D, Anaglyph of Shaded Relief

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This stereoscopic shaded relief image shows Africa's topography as measured by the Shuttle Radar Topography Mission (SRTM) in February 2000. Also shown are Madagascar, the Arabian Peninsula, and other adjacent regions. Previously, much of the topography here was not mapped in detail. Digital elevation data, such as provided by SRTM, are in high demand by scientists studying earthquakes, volcanism, and erosion patterns and for use in mapping and modeling hazards to human habitation. But the shape of Earth's surface affects nearly every natural process and human endeavor that occurs there, so elevation data are used in a wide range of applications. The image shown here is greatly reduced from the original data resolution, but still provides a good overview of the continent's landforms. It is best viewed while panning at full resolution while using image display software.

    The northern part of the continent consists of a system of basins and plateaus, with several volcanic uplands whose uplift has been matched by subsidence in the large surrounding basins. Many of these basins have been infilled with sand and gravel, creating the vast Saharan lands. The Atlas Mountains in the northwest were created by convergence of the African and Eurasian tectonic plates.

    The geography of the central latitudes of Africa is dominated by the Great Rift Valley, extending from Lake Nyasa to the Red Sea, and splitting into two arms to enclose an interior plateau and the nearly circular Lake Victoria, visible in the right center of the image. To the west lies the Congo Basin, a vast, shallow depression that rises to form an almost circular rim of highlands.

    Most of the southern part of the continent rests on a concave plateau comprising the Kalahari Basin and a mountainous fringe, skirted by a coastal plain that widens out in Mozambique in the southeast.

    Specific noteworthy features one may wish to explore in this scene include (1) the Richat Structure in

  7. Shaded Relief with Height as Color, North America

    NASA Technical Reports Server (NTRS)

    2003-01-01

    , and 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

  8. Effect of shade area on performance and welfare of short-fed feedlot cattle.

    PubMed

    Sullivan, M L; Cawdell-Smith, A J; Mader, T L; Gaughan, J B

    2011-09-01

    One hundred twenty-six Black Angus yearling heifers were used in a 119-d study to assess the effect of shade allocation (0, 2.0, 3.3, or 4.7 m(2)/animal) on the performance and welfare of feedlot cattle. Shade treatments were replicated 4 times and the no-shade treatment was replicated twice. Shade was provided by 70% solar block shade cloth, attached to a 4-m-high frame with a north-south orientation. Cattle were randomly allocated to a pen (9/pen; 19.2 m(2)/animal) within treatment. Performance was assessed using DMI, G:F, ADG, HCW, dressing percentage, and rump fat depth. Climatic data (ambient and black globe temperature, solar radiation, wind speed, relative humidity, and rainfall) were recorded. From these data, the heat load index (HLI) was calculated. When the daily maximum HLI (HLI(Max)) was <86, individual panting score (0 = no panting; 4 = open mouth, tongue extended), animal location (eating, drinking, under shade), and animal posture (standing or lying) were collected at 0600, 1200, and 1800 h. When HLI(Max) was ≥ 86, these data were collected every 2 h between 0600 and 1800 h. Feed intake was recorded weekly and water intake was recorded daily on a pen basis. When HLI(Max) was ≥ 86, mean panting score (MPS: mean of animals within treatment) was greatest (1.02; P < 0.001) for unshaded cattle compared with cattle in the shade treatments, which were similar (0.82; P = 0.81). During heat waves, the MPS of unshaded cattle was greater (2.66; P < 0.001) than that for shaded cattle. The MPS of cattle in the 2.0 m(2)/animal treatment (2.43 ± 0.13) was greater (P < 0.001) than that of cattle in the 3.3 (2.11 ± 0.13) and 4.7 m(2)/animal (2.03 ± 0.13) treatments. The MPS of cattle in the 3.3 and 4.7 m(2)/animal treatments were similar (P = 0.09). Number standing was similar (P = 0.98) between unshaded and shaded at 2.0 m(2)/animal treatments with 4.75 and 4.76 animals/pen, respectively. Fewer (P < 0.0001) were standing in the 3.3 (4.19 animals/pen) and 4

  9. Primary Production and Photoadaptation in Light- and Shade-Adapted Colonies of the Symbiotic Coral, Stylophora pistillata

    NASA Astrophysics Data System (ADS)

    Porter, J. W.; Muscatine, L.; Dubinsky, Z.; Falkowski, P. G.

    1984-08-01

    Photoadaptation by photosynthetic organisms to lowered light intensities occurs in part through changes in pigment concentrations and in characteristics of the photosynthetic response curve. We have characterized photoadaptive responses of light- and shade-adapted colonies of the reef coral Stylophora pistillata, which possesses symbiotic algae (zooxanthellae) and grows naturally under a variety of light intensities in the highly cavernous reefs of the Red Sea. Shade-adapted corals have significantly more chlorophyll per individual zooxanthella cell than light-adapted corals (2.98 compared to 12.97 pg chlorophyll a per cell), but not a significantly different number of cells per unit area (1.00 × 106 cells per square centimetre), with the result that the mass of chlorophyll per unit area is greater for shade-adapted corals than for light-adapted corals. Tissue nitrogen content per unit area is significantly lower (p < 0.05) in shade-adapted corals, correlating with a decrease in polyp density (0.10 > p > 0.05) in shade forms. These biomass characteristics are concomitant with a variety of functional responses to natural light intensities. Rate of photosynthesis at saturating light intensities is the same per unit area in both forms (20.2 μ g O2 cm-2 h-1 for shade specimens; 18.8 for light specimens); but it is significantly different when measured by amount of chlorophyll (1.6 μ g O2 (chl a)-1 h-1 for shade specimens compared with 5.0 for light specimens). The initial slope of the P:I curve, α , is significantly higher for shade specimens by area (0.21 for shade corals compared with 0.12 for light corals), but significantly lower for shade specimens by amount of chlorophyll a (0.01 for specimens from shade compared to 0.04 for specimens growing in the light). Ik (the point at which maximum production begins) is significantly lower for shade specimens (138 μ mol m-2 s-1 for shade compared to 273 for light), and likewise Ic (the compensation point at which net

  10. Influence of shade tolerance and development stage on the allometry of ten temperate tree species.

    PubMed

    Franceschini, Tony; Schneider, Robert

    2014-11-01

    Allometry studies the change in scale between two dimensions of an organism. The metabolic theory of ecology predicts invariant allometric scaling exponents, while empirical studies evidenced inter- and intra-specific variations. This work aimed at identifying the sources of variations of the allometric exponents at both inter- and intra-specific levels using stem analysis from 9,363 trees for ten Eastern Canada species with a large shade-tolerance gradient. Specifically, the yearly allometric exponents, α(v,DBH) [volume (v) and diameter at breast height (DBH)], β(v,h) [v and height (h)], and γ(h,DBH) (h and DBH) were modelled as a function of tree age for each species. α(v,DBH), and γ(h,DBH) increased with tree age and then reached a plateau ranging from 2.45 to 3.12 for α(v,DBH), and 0.874-1.48 for γ(h,DBH). Pine species presented a local maximum. No effect of tree age on β(v,h) was found for conifers, while it increased until a plateau ranging from 3.71 to 5.16 for broadleaves. The influence of shade tolerance on the growth trajectories was then explored. In the juvenile stage, α(v,DBH), and γ(h,DBH) increased with shade tolerance while β(v,h) was shade-tolerance independent. In the mature stage, β(v,h) increased with shade tolerance, whereas γ(h,DBH) decreased and α(v,DBH) was shade-tolerance independent. The interaction between development stage and shade tolerance for allometric exponents demonstrates the importance of the changing functional requirements of trees for resource allocation at both the inter- and intra-specific level. These results indicate the need to also integrate specific functional traits, growth strategies and allocation, in allometric theoretical frameworks. PMID:25168006

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

    PubMed

    Bisseleua Daghela, Hervé Bertin; Bisseleua, Hervé Bertin Daghela; Fotio, Daniel; Yede; Missoup, Alain Didier; Vidal, Stefan

    2013-01-01

    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. PMID:23520451

  12. Shade Tree Diversity, Cocoa Pest Damage, Yield Compensating Inputs and Farmers' Net Returns in West Africa

    PubMed Central

    Daghela Bisseleua, Hervé Bertin; Fotio, Daniel; Yede; Missoup, Alain Didier; Vidal, Stefan

    2013-01-01

    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. PMID:23520451

  13. Riparian shading and groundwater enhance growth potential for smallmouth bass in Ozark streams.

    PubMed

    Whitledge, Gregory W; Rabeni, Charles F; Annis, Gust; Sowa, Scott P

    2006-08-01

    Moderation of stream temperatures by riparian shading and groundwater are known to promote growth and survival of salmonid fishes, but effects of riparian shade and groundwater on to be growth of warmwater stream fishes are poorly understood or assumed to be negligible. We used stream temperature models to relate shading from riparian vegetation and groundwater inflow to summer water temperatures in Missouri Ozark streams and evaluated effects of summer water temperatures on smallmouth bass, Micropterus dolomieu, growth using a bioenergetics model. Bioenergetics model simulations revealed that adult smallmouth bass in non-spring-fed streams have lower growth potential during summer than fish in spring-fed streams, are subject to mass loss when stream temperatures exceed 27 degrees C, and will likely exhibit greater interannual variation in growth during summer if all growth-influencing factors, other than temperature, are identical between the two stream types. Temperature models indicated that increased riparian shading will expand the longitudinal extent of thermal habitat capable of supporting adult smallmouth bass growth in spring-fed stream reaches when mean daily air temperatures exceed 27 degrees C. Optimum growth temperature (22 degrees C) will be present only in spring-fed streams under these conditions. Potential for increasing shade through riparian restoration is greatest for streams <5 m wide and along north-south reaches of larger streams. However, temperature models also indicated that restoring riparian shading to maximum levels throughout a watershed would increase the total stream mileage capable of supporting positive growth of adult smallmouth bass by only 1-6% when air temperatures are at or near average summer maxima; increases in suitable thermal habitat would be greatest in watersheds with higher spring densities. Riparian management for maintenance or restoration of the thermal habitat of adult smallmouth bass during summer should be

  14. Do shade-grown coffee plantations pose a disease risk for wild birds?

    PubMed

    Hernandez, Sonia M; Peters, Valerie E; Weygandt, P Logan; Jimenez, Carlos; Villegas, Pedro; O'Connor, Barry; Yabsley, Michael J; Garcia, Maricarmen; Riblet, Sylva M; Carroll, C Ron

    2013-06-01

    Shade-grown coffee plantations are often promoted as a conservation strategy for wild birds. However, these agro-ecosystems are actively managed for food production, which may alter bird behaviors or interactions that could change bird health, compared to natural forest. To examine whether there is a difference between the health parameters of wild birds inhabiting shade-grown coffee plantations and natural forest, we evaluated birds in Costa Rica for (1) their general body condition, (2) antibodies to pathogens, (paramyxovirus and Mycoplasma spp.), and (3) the prevalence and diversity of endo-, ecto-, and hemoparasites. We measured exposure to Mycoplasma spp. and paramyxovirus because these are pathogens that could have been introduced with domestic poultry, one mechanism by which these landscapes could be detrimental to wild birds. We captured 1,561 birds representing 75 species. Although seasonal factors influenced body condition, we did not find bird general body condition to be different. A total of 556 birds of 31 species were tested for antibodies against paramyxovirus-1. Of these, five birds tested positive, four of which were from shade coffee. Out of 461 other tests for pathogens (for antibodies and nucleotide detection), none were positive. Pterolichus obtusus, the feather mite of chickens, was found on 15 birds representing two species and all were from shade-coffee plantations. Larvated eggs of Syngamus trachea, a nematode typically associated with chickens, were found in four birds captured in shade coffee and one captured in forest. For hemoparasites, a total of 1,121 blood smears from 68 bird species were examined, and only one species showed a higher prevalence of infection in shade coffee. Our results indicate that shade-coffee plantations do not pose a significant health risk to forest birds, but at least two groups of pathogens may deserve further attention: Haemoproteus spp. and the diversity and identity of endoparasites.

  15. Evaluating the Community Land Model in a pine stand with 13CO2 labeling and shading manipulations

    NASA Astrophysics Data System (ADS)

    Mao, J.; Ricciuto, D. M.; Thornton, P. E.; Warren, J. M.; King, A. W.; Shi, X.; Iversen, C. M.; Norby, R. J.

    2015-05-01

    Carbon allocation and flow through ecosystems regulate land surface-atmosphere CO2 exchange and thus is a key, albeit uncertain, component of mechanistic models. The Partitioning in Trees and Soil (PiTS) experiment-model project tracked carbon allocation through a young Pinus taeda stand following pulse-labeling with 13CO2 and two levels of shading. The field component of this project provided process-oriented data that was used to evaluate and improve terrestrial biosphere model simulations of rapid shifts in carbon allocation and hydrological dynamics under varying environmental conditions. Here we tested the performance of the Community Land Model version 4 (CLM4) in capturing short-term carbon and water dynamics in relation to manipulative shading treatments, and the timing and magnitude of carbon fluxes through various compartments of the ecosystem. For CLM4 to closely simulate pretreatment conditions, we calibrated select model parameters with pretreatment observational data. Compared to CLM4 simulations with default parameters, CLM4 with calibrated model parameters was able to better simulate pretreatment vegetation carbon pools, light response curves, and other initial states and fluxes of carbon and water. Over a 3 week treatment period, the calibrated CLM4 generally reproduced the impacts of shading on average soil moisture at 15-95 cm depth, transpiration, relative change in stem carbon, and soil CO2 efflux rate, although some discrepancies in the estimation of magnitudes and temporal evolutions existed. CLM4, however, was not able to track the progression of the 13CO2 label from the atmosphere through foliage, phloem, roots or surface soil CO2 efflux, even when optimized model parameters were used. This model bias arises, in part, from the lack of a short-term non-structural carbohydrate storage pool and progressive timing of within-plant transport, thus indicating a need for future work to improve the allocation routines in CLM4. Overall, these types

  16. Evaluating the Community Land Model in a pine stand with shading manipulations and 13CO2 labeling

    DOE PAGES

    Mao, Jiafu; Ricciuto, Daniel M.; Thornton, Peter E.; Warren, Jeffrey M.; King, Anthony Wayne; Shi, Xiaoying; Iversen, Colleen M.; Norby, Richard J.

    2016-02-03

    Carbon partitioning and flow through ecosystems regulates land surface atmosphere CO2 exchange and thus is a key, albeit uncertain component of mechanistic models. The Partitioning in Trees and Soil (PiTS) experiment-model project tracked C partitioning through a young Pinus taeda stand following pulse-labeling with 13CO2 and two levels of shading. The field component of this project provided process-oriented data that was used to evaluate and improve terrestrial biosphere model simulations of rapid shifts in carbon partitioning and hydrological dynamics under varying environmental conditions. Here we tested the performance of the Community Land Model version 4 (CLM4) in capturing short-term carbonmore » and water dynamics in relation to manipulative shading treatments, and the timing and magnitude of carbon fluxes through various compartments of the ecosystem. To constrain CLM4 to closely simulate pretreatment conditions, we calibrated select model parameters with the pretreatment observational data. Compared to CLM4 simulations with default parameters, CLM4 with calibrated model parameters was better able to simulate pretreatment vegetation carbon pools, light response curves, and other initial states and fluxes of carbon and water. Over a 3-week treatment period, the calibrated CLM4 generally reproduced the impacts of shading on average soil moisture at 15-95 cm depth, transpiration, relative change in stem carbon, and soil CO2 efflux rate, although some discrepancies in the estimation of magnitudes and temporal evolutions existed. CLM4, however, was not able to track the progression of the 13CO2 label from the atmosphere through foliage, phloem, roots or surface soil CO2 efflux, even when optimized model parameters were used. This model bias arises, in part, from the lack of a short-term non-structural carbohydrate storage pool and progressive timing of within-plant transport, thus indicating a need for future work to improve the allocation routines in CLM4

  17. Reconciling species-level vs plastic responses of evergreen leaf structure to light gradients: shade leaves punch above their weight.

    PubMed

    Lusk, Christopher H; Onoda, Yusuke; Kooyman, Robert; Gutiérrez-Girón, Alba

    2010-04-01

    *When grown in a common light environment, the leaves of shade-tolerant evergreen trees have a larger leaf mass per unit area (LMA) than their light-demanding counterparts, associated with differences in lifespan. Yet plastic responses of LMA run counter to this pattern: shade leaves have smaller LMA than sun leaves, despite often living longer. *We measured LMA and cell wall content, and conducted punch and shear tests, on sun and shade leaves of 13 rainforest evergreens of differing shade tolerance, in order to understand adaptation vs plastic responses of leaf structure and biomechanics to shade. *Species shade tolerance and leaf mechanical properties correlated better with cell wall mass per unit area than with LMA. Growth light environment had less effect on leaf mechanics than on LMA: shade leaves had, on average, 40% lower LMA than sun leaves, but differences in work-to-shear, and especially force-to-punch, were smaller. This was associated with a slightly larger cell wall fraction in shade leaves. *The persistence of shade leaves might reflect unattractiveness to herbivores because they yield smaller benefits (cell contents per area) per unit fracture force than sun leaves. In forest trees, cell wall fraction and force-to-punch are more robust correlates of species light requirements than LMA.

  18. Tanning Shade Gradations of Models in Mainstream Fitness and Muscle Enthusiast Magazines: Implications for Skin Cancer Prevention in Men.

    PubMed

    Basch, Corey H; Hillyer, Grace Clarke; Ethan, Danna; Berdnik, Alyssa; Basch, Charles E

    2015-07-01

    Tanned skin has been associated with perceptions of fitness and social desirability. Portrayal of models in magazines may reflect and perpetuate these perceptions. Limited research has investigated tanning shade gradations of models in men's versus women's fitness and muscle enthusiast magazines. Such findings are relevant in light of increased incidence and prevalence of melanoma in the United States. This study evaluated and compared tanning shade gradations of adult Caucasian male and female model images in mainstream fitness and muscle enthusiast magazines. Sixty-nine U.S. magazine issues (spring and summer, 2013) were utilized. Two independent reviewers rated tanning shade gradations of adult Caucasian male and female model images on magazines' covers, advertisements, and feature articles. Shade gradations were assessed using stock photographs of Caucasian models with varying levels of tanned skin on an 8-shade scale. A total of 4,683 images were evaluated. Darkest tanning shades were found among males in muscle enthusiast magazines and lightest among females in women's mainstream fitness magazines. By gender, male model images were 54% more likely to portray a darker tanning shade. In this study, images in men's (vs. women's) fitness and muscle enthusiast magazines portrayed Caucasian models with darker skin shades. Despite these magazines' fitness-related messages, pro-tanning images may promote attitudes and behaviors associated with higher skin cancer risk. To date, this is the first study to explore tanning shades in men's magazines of these genres. Further research is necessary to identify effects of exposure to these images among male readers.

  19. Implementation of window shading models into dynamic whole-building simulation

    NASA Astrophysics Data System (ADS)

    Lomanowski, Bartosz Aleksander

    An important consideration in energy efficient building design is the management of solar gain, as it is the largest and most variable gain in a building. The design of buildings with highly glazed facades, as well as decreased energy transfer rates through better insulated and tighter envelopes are causing interior spaces to become highly sensitive to solar gain. Shading devices such as operable slat-type louver blinds are very effective in controlling solar gain, yet their impact on peak cooing loads and annual energy consumption is poorly understood. With the ever-increasing role of building energy simulation tools in the design of energy efficient buildings, there is a clear need to model windows with shading devices to assess their impact on building performance. Recent efforts at the University of Waterloo's Advanced Glazing Systems Laboratory (AGSL) in window shading research have produced a set of flexible shading models. These models were developed with emphasis on generality and computational efficiency, ideally suited for integration into building simulation. The objective of the current research is to develop a complex fenestration facility within a general purpose integrated building simulation software tool, ESP-r, using the AGSL shading models. The strategy for implementation of the AGSL shading models is the addition of a new multi-layer construction within ESP-r, the Complex Fenestration Construction (CFC). The CFC is based on the standard ESP-r multi-layer nodal structure and finite control volume numerical model, with additional measures for coping with the complexities that arise in the solar, convective and radiant exchanges between glazing/shading layers, the interior zone and exterior surroundings. The CFC algorithms process the solar, convective and radiant properties of the glazing/shading system at each time-step, making it possible to add control (e.g., changing the slat angle of a slat-type blind) at the time-step level. Thermal

  20. Regulation of Black Pepper Inflorescence Quantity by Shading at Different Growth Stages.

    PubMed

    Zu, Chao; Wu, Guiping; Li, Zhigang; Yang, Jianfeng; Wang, Can; Yu, Huan; Wu, Huasong

    2016-07-01

    Black pepper is a perennial plant that can bloom throughout the year. It is generally expected that pepper inflorescence quantity could be minimized at the nonfull-bloom stage. The objective of this study was to find an appropriate shading measure that could inhibit blooming at other growing stages except the full-bloom stage and did not cause any reduction in pepper yield and quality. In this study, pepper trees were shaded up to 15%, 30%, 60% and 75%, respectively, and the inflorescence quantity, photosynthetic characteristics, pepper yield and quality traits were investigated at every growing stage. The results showed that the effect of shading on pepper yield decreased as time progressed. Shading treatment did not alter the composition of piperine and volatile oil, but reduced the moisture content. Based on the correlation between photosynthetic parameter and inflorescence number, the appropriate shading intensities for regulating inflorescence quantity at different phenological stages were determined. Moreover, it was found that the regulation of inflorescence quantity could be achieved by controlling leaf temperature during recovery to filling period. This research outcome also will give us some guidelines to develop other management strategies that control leaf temperature and regulate inflorescence quantity to consequently improve pepper yield. PMID:27144907

  1. BRANCHED1 Promotes Axillary Bud Dormancy in Response to Shade in Arabidopsis[C][W

    PubMed Central

    González-Grandío, Eduardo; Poza-Carrión, César; Sorzano, Carlos Oscar S.; Cubas, Pilar

    2013-01-01

    Plants interpret a decrease in the red to far-red light ratio (R:FR) as a sign of impending shading by neighboring vegetation. This triggers a set of developmental responses known as shade avoidance syndrome. One of these responses is reduced branching through suppression of axillary bud outgrowth. The Arabidopsis thaliana gene BRANCHED1 (BRC1), expressed in axillary buds, is required for branch suppression in response to shade. Unlike wild-type plants, brc1 mutants develop several branches after a shade treatment. BRC1 transcription is positively regulated 4 h after exposure to low R:FR. Consistently, BRC1 is negatively regulated by phytochrome B. Transcriptional profiling of wild-type and brc1 buds of plants treated with simulated shade has revealed groups of genes whose mRNA levels are dependent on BRC1, among them a set of upregulated abscisic acid response genes and two networks of cell cycle– and ribosome-related downregulated genes. The downregulated genes have promoters enriched in TEOSINTE BRANCHED1, CYCLOIDEA, and PCF (TCP) binding sites, suggesting that they could be transcriptionally regulated by TCP factors. Some of these genes respond to BRC1 in seedlings and buds, supporting their close relationship with BRC1 activity. This response may allow the rapid adaptation of plants to fluctuations in the ratio of R:FR light. PMID:23524661

  2. Influence of shade and irradiation time on the hardness of composite resins.

    PubMed

    Della Bona, Alvaro; Rosa, Vinícius; Cecchetti, Dileta

    2007-01-01

    This study tested the following hypotheses: 1. increasing light irradiation time (IT) produces greater values of superficial hardness on different depths (0 and 3 mm); and 2. a dark shade composite (A3) needs longer IT than a light shade composite (A1) to produce similar hardness. Disk-shaped specimens (n=24 per shade) were fabricated using a 3-mm-thick increment of composite resin (Z100). Specimens were randomly assigned to 3 groups (n=8) according to the IT (400 mW/cm2) at the upper (U) surface: A1-10 and A3-10: 10 s; A1-20 and A3-20: 20 s; A1-40 and A3-40: 40 s. Specimens were stored in black lightproof containers at 37 masculineC for 24 h before indentation in a hardness tester. Three Vickers indentations were performed on the U and lower (L) surfaces of each specimen. The indent diagonals were measured and the hardness value calculated. The results were analyzed statistically by ANOVA and Tukey's test (alpha=0.05). Statistically significant differences were found between U and L surfaces of each composite shade-IT combination (p=0.0001) and among the ITs of same shade-surface combination (p=0.0001), except between groups A1-20U and A1-40U, confirming the study hypothesis 1 and partially rejecting the hypothesis 2.

  3. Transcriptome Analysis of Shade-Induced Inhibition on Leaf Size in Relay Intercropped Soybean

    PubMed Central

    Gong, Wanzhuo; Qi, Pengfei; Du, Junbo; Sun, Xin; Wu, Xiaoling; Song, Chun; Liu, Weiguo; Wu, Yushan; Yu, Xiaobo; Yong, Taiwen; Wang, Xiaochun; Yang, Feng; Yan, Yanhong; Yang, Wenyu

    2014-01-01

    Multi-species intercropping is a sustainable agricultural practice worldwide used to utilize resources more efficiently. In intercropping systems, short crops often grow under vegetative shade of tall crops. Soybean, one important legume, is often planted in intercropping. However, little is known about the mechanisms of shade inhibition effect on leaf size in soybean leaves at the transcriptome level. We analyzed the transcriptome of shaded soybean leaves via RNA-Seq technology. We found that transcription 1085 genes in mature leaves and 1847 genes in young leaves were significantly affected by shade. Gene ontology analyses showed that expression of genes enriched in polysaccharide metabolism was down-regulated, but genes enriched in auxin stimulus were up-regulated in mature leaves; and genes enriched in cell cycling, DNA-replication were down-regulated in young leaves. These results suggest that the inhibition of higher auxin content and shortage of sugar supply on cell division and cell expansion contribute to smaller and thinner leaf morphology, which highlights potential research targets such as auxin and sugar regulation on leaves for crop adaptation to shade in intercropping. PMID:24886785

  4. Transcriptome analysis of shade-induced inhibition on leaf size in relay intercropped soybean.

    PubMed

    Gong, Wanzhuo; Qi, Pengfei; Du, Junbo; Sun, Xin; Wu, Xiaoling; Song, Chun; Liu, Weiguo; Wu, Yushan; Yu, Xiaobo; Yong, Taiwen; Wang, Xiaochun; Yang, Feng; Yan, Yanhong; Yang, Wenyu

    2014-01-01

    Multi-species intercropping is a sustainable agricultural practice worldwide used to utilize resources more efficiently. In intercropping systems, short crops often grow under vegetative shade of tall crops. Soybean, one important legume, is often planted in intercropping. However, little is known about the mechanisms of shade inhibition effect on leaf size in soybean leaves at the transcriptome level. We analyzed the transcriptome of shaded soybean leaves via RNA-Seq technology. We found that transcription 1085 genes in mature leaves and 1847 genes in young leaves were significantly affected by shade. Gene ontology analyses showed that expression of genes enriched in polysaccharide metabolism was down-regulated, but genes enriched in auxin stimulus were up-regulated in mature leaves; and genes enriched in cell cycling, DNA-replication were down-regulated in young leaves. These results suggest that the inhibition of higher auxin content and shortage of sugar supply on cell division and cell expansion contribute to smaller and thinner leaf morphology, which highlights potential research targets such as auxin and sugar regulation on leaves for crop adaptation to shade in intercropping.

  5. [Effects of shading on photosynthesis characteristics of Photinia x frasery and Aucuba japonica var. variegata].

    PubMed

    Zhang, Cong-ying; Fang, Yan-ming; Ji, Hong-li; Ma, Cheng-tao

    2011-07-01

    This paper studied the effects of different shading (light transmittance 20%, 40%, 60%, and 100%) on the photosynthesis characteristics of two ornamental foliage plants Photinia x frasery and Aucuba japonica var. variegata. After shading for six weeks, the net photosynthesis rates of two plants measured ex situ under natural light enhanced, compared to those measured in situ, and, with the increase of shading degree, the net photosynthetic rates had an increasing trend, with the maximum being 9.7 micromol x m(-2) x s(-1) for Photinia x frasery and 8.3 micromol x m(-2) x s(-1) for Aucuba japonica var. variegata. In the meantime, the transpiration rates of the two plants increased significantly. Shading increased the chlorophyll a, b, and a+b contents and the chlorophyll/carotenoids ratio, decreased the chlorophyll a/b, but less affected the carotenoids content. The phenotypic plasticity index (PPI) of net photosynthesis rate and transpiration rate of Photinia x frasery and Aucuba japonica var. variegate was 2.08 and 3.21, and 0.55 and 1.60, respectively. The chlorophyll and carotenoids contents of the two plants were relatively stable, indicating the minor influence of external environment factors on pigments. Aucuba japonica var. variegata had a higher shading tolerance than Photinia x frasery.

  6. Regulation of Black Pepper Inflorescence Quantity by Shading at Different Growth Stages.

    PubMed

    Zu, Chao; Wu, Guiping; Li, Zhigang; Yang, Jianfeng; Wang, Can; Yu, Huan; Wu, Huasong

    2016-07-01

    Black pepper is a perennial plant that can bloom throughout the year. It is generally expected that pepper inflorescence quantity could be minimized at the nonfull-bloom stage. The objective of this study was to find an appropriate shading measure that could inhibit blooming at other growing stages except the full-bloom stage and did not cause any reduction in pepper yield and quality. In this study, pepper trees were shaded up to 15%, 30%, 60% and 75%, respectively, and the inflorescence quantity, photosynthetic characteristics, pepper yield and quality traits were investigated at every growing stage. The results showed that the effect of shading on pepper yield decreased as time progressed. Shading treatment did not alter the composition of piperine and volatile oil, but reduced the moisture content. Based on the correlation between photosynthetic parameter and inflorescence number, the appropriate shading intensities for regulating inflorescence quantity at different phenological stages were determined. Moreover, it was found that the regulation of inflorescence quantity could be achieved by controlling leaf temperature during recovery to filling period. This research outcome also will give us some guidelines to develop other management strategies that control leaf temperature and regulate inflorescence quantity to consequently improve pepper yield.

  7. BRANCHED1 promotes axillary bud dormancy in response to shade in Arabidopsis.

    PubMed

    González-Grandío, Eduardo; Poza-Carrión, César; Sorzano, Carlos Oscar S; Cubas, Pilar

    2013-03-01

    Plants interpret a decrease in the red to far-red light ratio (R:FR) as a sign of impending shading by neighboring vegetation. This triggers a set of developmental responses known as shade avoidance syndrome. One of these responses is reduced branching through suppression of axillary bud outgrowth. The Arabidopsis thaliana gene BRANCHED1 (BRC1), expressed in axillary buds, is required for branch suppression in response to shade. Unlike wild-type plants, brc1 mutants develop several branches after a shade treatment. BRC1 transcription is positively regulated 4 h after exposure to low R:FR. Consistently, BRC1 is negatively regulated by phytochrome B. Transcriptional profiling of wild-type and brc1 buds of plants treated with simulated shade has revealed groups of genes whose mRNA levels are dependent on BRC1, among them a set of upregulated abscisic acid response genes and two networks of cell cycle- and ribosome-related downregulated genes. The downregulated genes have promoters enriched in TEOSINTE BRANCHED1, CYCLOIDEA, and PCF (TCP) binding sites, suggesting that they could be transcriptionally regulated by TCP factors. Some of these genes respond to BRC1 in seedlings and buds, supporting their close relationship with BRC1 activity. This response may allow the rapid adaptation of plants to fluctuations in the ratio of R:FR light.

  8. Drought and shade deplete nonstructural carbohydrate reserves in seedlings of five temperate tree species.

    PubMed

    Maguire, Andrea J; Kobe, Richard K

    2015-12-01

    Plants that store nonstructural carbohydrates (NSC) may rely on carbon reserves to survive carbon-limiting stress, assuming that reserves can be mobilized. We asked whether carbon reserves decrease in resource stressed seedlings, and if NSC allocation is related to species' relative stress tolerances. We tested the effects of stress (shade, drought, and defoliation) on NSC in seedlings of five temperate tree species (Acer rubrum Marsh., Betula papyrifera Marsh., Fraxinus americana L ., Quercus rubra L., and Quercus velutina Lam.). In a greenhouse experiment, seedlings were subjected to combinations of shade, drought, and defoliation. We harvested seedlings over 32-97 days and measured biomass and NSC concentrations in stems and roots to estimate depletion rates. For all species and treatments, except for defoliation, seedling growth and NSC accumulation ceased. Shade and drought combined caused total NSC decreases in all species. For shade or drought alone, only some species experienced decreases. Starch followed similar patterns as total NSC, but soluble sugars increased under drought for drought-tolerant species. These results provide evidence that species deplete stored carbon in response to carbon limiting stress and that species differences in NSC response may be important for understanding carbon depletion as a buffer against shade- and drought-induced mortality.

  9. Africa in SRTM 3-D, Anaglyph of Shaded Relief

    NASA Technical Reports Server (NTRS)

    2004-01-01

    This stereoscopic shaded relief image shows Africa's topography as measured by the Shuttle Radar Topography Mission (SRTM) in February 2000. Also shown are Madagascar, the Arabian Peninsula, and other adjacent regions. Previously, much of the topography here was not mapped in detail. Digital elevation data, such as provided by SRTM, are in high demand by scientists studying earthquakes, volcanism, and erosion patterns and for use in mapping and modeling hazards to human habitation. But the shape of Earth's surface affects nearly every natural process and human endeavor that occurs there, so elevation data are used in a wide range of applications. The image shown here is greatly reduced from the original data resolution, but still provides a good overview of the continent's landforms. It is best viewed while panning at full resolution while using image display software.

    The northern part of the continent consists of a system of basins and plateaus, with several volcanic uplands whose uplift has been matched by subsidence in the large surrounding basins. Many of these basins have been infilled with sand and gravel, creating the vast Saharan lands. The Atlas Mountains in the northwest were created by convergence of the African and Eurasian tectonic plates.

    The geography of the central latitudes of Africa is dominated by the Great Rift Valley, extending from Lake Nyasa to the Red Sea, and splitting into two arms to enclose an interior plateau and the nearly circular Lake Victoria, visible in the right center of the image. To the west lies the Congo Basin, a vast, shallow depression that rises to form an almost circular rim of highlands.

    Most of the southern part of the continent rests on a concave plateau comprising the Kalahari Basin and a mountainous fringe, skirted by a coastal plain that widens out in Mozambique in the southeast.

    Specific noteworthy features one may wish to explore in this scene include (1) the Richat Structure in

  10. Sedimentation and water quality in the West Branch Shade River basin, Ohio, 1983-85

    USGS Publications Warehouse

    Oblinger Childress, C. J.; Jones, R.L.

    1988-01-01

    Loss of channel conveyance from deposition of sediment from abandoned surface mines in the West Branch Shade River basin has resulted in frequent flooding. In addition, water quality in the West Branch Shade River and some of its tributaries is typical of streams affected by acid mine drainage. About 938 acres were surfaced mined and abandoned in West Branch Shade River basin. By the end of 1984, about 450 acres were reclaimed. The purpose of this study was to measure the effects of abandoned surface mines and their reclamation on suspended-sediment load, channel cross-section profile, and water quality of West Branch Shade River. Sediment data were collected from June 1983 through September 1985. Daily suspended-sediment samples were collected and continuous streamflow data were recorded at two locations in West Branch Shade River basin and one location in the unmined, East Branch Shade River basin. Water-quality samples were collected three times per year, from June 1983 through July 1986, at four locations in the West Branch Shade River basin and at one location in East Branch Shade River basin and at one location in East Branch Shade River basin. Stream-channel cross sections were surveyed at least twice per year at 10 locations. During the period of study, annual mean suspended-sediment concentration was unchanged for the unmined, East Branch Shade River basin; 0.28 ton per acre-foot of runoff in 1984 and 1985 water years. Annual suspended-sediment concentration, in tons per acre foot, in West Branch Shade River near Harrisonville, from 8.6 in 1984 water year to 0.15 in 1985 water year. In West Branch Shade River near Burlingham, where 48 percent of the abandoned mines were reclaimed by the end of 1984, annual mean suspended-sediment concentration was unchanged (0.5 ton per acre-foot of runoff) in 1984 and 1985 water years and was twice that of the unmined basin. Channel profiles, surveyed at each of the 10 cross sections, indicated scouring at two locations

  11. Optical and color stabilities of paint-on resins for shade modification of restorative resins.

    PubMed

    Arikawa, Hiroyuki; Kanie, Takahito; Fujii, Koichi; Ban, Seiji; Homma, Tetsuya; Takahashi, Hideo

    2004-06-01

    The purpose of this study was to examine the optical and color stabilities of the paint-on resin used for shade modification of restorative resins. Three shades of paint-on resin and two crown and bridge resins were used. The light transmittance characteristics of the materials during accelerated aging tests such as water immersion, toothbrush abrasion, ultraviolet (UV) light irradiation, and staining tests were measured. Discolorations of materials resulting from tests were also determined. There were no significant effects of water immersion, toothbrush abrasion and UV light irradiation on the light transmittance and visible color change of paint-on resins, whereas the staining tests significantly decreased the light transmittance and increased color change of the translucent shades of materials. Our results indicate that the paint-on resins exhibit stable optical properties and color appearance, which are at least as good as the crown and bridge resins.

  12. Regulation of Carotenoid Biosynthesis by Shade Relies on Specific Subsets of Antagonistic Transcription Factors and Cofactors.

    PubMed

    Bou-Torrent, Jordi; Toledo-Ortiz, Gabriela; Ortiz-Alcaide, Miriam; Cifuentes-Esquivel, Nicolas; Halliday, Karen J; Martinez-García, Jaime F; Rodriguez-Concepcion, Manuel

    2015-11-01

    Carotenoids are photosynthetic pigments essential for the protection against excess light. During deetiolation, their production is regulated by a dynamic repression-activation module formed by PHYTOCHROME-INTERACTING FACTOR1 (PIF1) and LONG HYPOCOTYL5 (HY5). These transcription factors directly and oppositely control the expression of the gene encoding PHYTOENE SYNTHASE (PSY), the first and main rate-determining enzyme of the carotenoid pathway. Antagonistic modules also regulate the responses of deetiolated plants to vegetation proximity and shade (i.e. to the perception of far-red light-enriched light filtered through or reflected from neighboring plants). These responses, aimed to adapt to eventual shading from plant competitors, include a reduced accumulation of carotenoids. Here, we show that PIF1 and related photolabile PIFs (but not photostable PIF7) promote the shade-triggered decrease in carotenoid accumulation. While HY5 does not appear to be required for this process, other known PIF antagonists were found to modulate the expression of the Arabidopsis (Arabidopsis thaliana) PSY gene and the biosynthesis of carotenoids early after exposure to shade. In particular, PHYTOCHROME-RAPIDLY REGULATED1, a transcriptional cofactor that prevents the binding of true transcription factors to their target promoters, was found to interact with PIF1 and hence directly induce PSY expression. By contrast, a change in the levels of the transcriptional cofactor LONG HYPOCOTYL IN FAR RED1, which also binds to PIF1 and other PIFs to regulate shade-related elongation responses, did not impact PSY expression or carotenoid accumulation. Our data suggest that the fine-regulation of carotenoid biosynthesis in response to shade relies on specific modules of antagonistic transcriptional factors and cofactors.

  13. Native Environment Modulates Leaf Size and Response to Simulated Foliar Shade across Wild Tomato Species

    PubMed Central

    Filiault, Daniele L.; Kumar, Ravi; Jiménez-Gómez, José M.; Schrager, Amanda V.; Park, Daniel S.; Peng, Jie; Sinha, Neelima R.; Maloof, Julin N.

    2012-01-01

    The laminae of leaves optimize photosynthetic rates by serving as a platform for both light capture and gas exchange, while minimizing water losses associated with thermoregulation and transpiration. Many have speculated that plants maximize photosynthetic output and minimize associated costs through leaf size, complexity, and shape, but a unifying theory linking the plethora of observed leaf forms with the environment remains elusive. Additionally, the leaf itself is a plastic structure, responsive to its surroundings, further complicating the relationship. Despite extensive knowledge of the genetic mechanisms underlying angiosperm leaf development, little is known about how phenotypic plasticity and selective pressures converge to create the diversity of leaf shapes and sizes across lineages. Here, we use wild tomato accessions, collected from locales with diverse levels of foliar shade, temperature, and precipitation, as a model to assay the extent of shade avoidance in leaf traits and the degree to which these leaf traits correlate with environmental factors. We find that leaf size is correlated with measures of foliar shade across the wild tomato species sampled and that leaf size and serration correlate in a species-dependent fashion with temperature and precipitation. We use far-red induced changes in leaf length as a proxy measure of the shade avoidance response, and find that shade avoidance in leaves negatively correlates with the level of foliar shade recorded at the point of origin of an accession. The direction and magnitude of these correlations varies across the leaf series, suggesting that heterochronic and/or ontogenic programs are a mechanism by which selective pressures can alter leaf size and form. This study highlights the value of wild tomato accessions for studies of both morphological and light-regulated development of compound leaves, and promises to be useful in the future identification of genes regulating potentially adaptive plastic

  14. Photoinhibition and drought in Mediterranean woody saplings: scaling effects and interactions in sun and shade phenotypes.

    PubMed

    Valladares, Fernando; Dobarro, Iker; Sánchez-Gómez, David; Pearcy, Robert W

    2005-01-01

    Interacting effects of high light and drought on the performance of sun and shade phenotypes were experimentally undertaken following survival, chlorophyll fluorescence and gas exchange in 2-year-old saplings of four Mediterranean trees (Quercus ilex and Q. coccifera as water-saving species, and Pistacia lentiscus and P. terebinthus as water-spending species). Half of the saplings were grown in full sunlight and the other half in the shade (6% sunlight). Half of each combination of species-phenotype was exposed to high light during a simulated late-summer drought. Light absorptance and gas exchange were scaled up to the whole plant with the 3-D geometrical model, Y-Plant. Quercus species were more plastic and tolerated high light and water stress better than Pistacia species, surviving longer and in drier soils, and exhibiting a less pronounced photoinhibition. There was no evidence of disadvantage for shade phenotypes under high light with increasing drought. By contrast, shade phenotypes survived longer despite larger initial decreases in photochemical efficiency and higher sensitivity to drought than sun phenotypes. The enhanced control of transpiration during drought in water-saving versus water-spending species (and also in shade versus sun phenotypes in three out of the four species) allowed extended survival. Photoinhibition reduced whole crown carbon gain in high light by c. 3% and affected significantly more the shaded leaves of a given plant (reducing their carbon gain by up to 7%) than those exposed to direct sunlight. Despite this apparently minor impact, whole plant carbon gain reduction by photoinhibition negatively correlated with survival and drought tolerance. The implications for succession and forest regeneration in arid environments, particularly under a global change scenario, are discussed. PMID:15569705

  15. Shading by napier grass reduces malaria vector larvae in natural habitats in Western Kenya highlands.

    PubMed

    Wamae, Peter M; Githeko, Andrew K; Menya, Diana M; Takken, Willem

    2010-12-01

    Increased human population in the Western Kenya highlands has led to reclamation of natural swamps resulting in the creation of habitats suitable for the breeding of Anopheles gambiae, the major malaria vector in the region. Here we report on a study to restore the reclaimed swamp and reverse its suitability as a habitat for malaria vectors. Napier grass-shaded and non-shaded water channels in reclaimed sites in Western Kenya highlands were studied for the presence and density of mosquito larvae, mosquito species composition, and daily variation in water temperature. Shading was associated with 75.5% and 88.4% (P < 0.0001) reduction in anopheline larvae densities and 78.1% and 88% (P < 0.0001) reduction in Anopheles gambiae sensu lato (s.l.) densities in two sites, respectively. Shading was associated with a 5.7°C, 5.0°C, and 4.7°C, and 1.6°C, 3.9°C, and 2.8°C (for maximum, minimum, and average temperatures, respectively) reduction (P < 0.0001) in water temperatures in the two locations, respectively. An. gambiae s.l. was the dominant species, constituting 83.2% and 73.1%, and 44.5% and 42.3%, of anophelines in non-shaded and shaded channels, respectively, in the two sites, respectively. An. gambiae sensu stricto (s.s.) constituted the majority (97.4%) of An. gambiae s.l., while the rest (2.6%) comprised of Anopheles arabiensis. Minimum water temperature decreased with increasing grass height (P = 0.0039 and P = 0.0415 for Lunyerere and Emutete sites, respectively). The results demonstrate how simple environmental strategies can have a strong impact on vector densities.

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

    NASA Astrophysics Data System (ADS)

    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.

  17. The Effect of Elevated Ozone Concentrations with Varying Shading on Dry Matter Loss in a Winter Wheat-Producing Region in China.

    PubMed

    Xu, Jingxin; Zheng, Youfei; He, Yuhong; Wu, Rongjun; Mai, Boru; Kang, Hanqing

    2016-01-01

    Surface-level ozone pollution causes crop production loss by directly reducing healthy green leaf area available for carbon fixation. Ozone and its precursors also affect crop photosynthesis indirectly by decreasing solar irradiance. Pollutants are reported to have become even more severe in Eastern China over the last ten years. In this study, we investigated the effect of a combination of elevated ozone concentrations and reduced solar irradiance on a popular winter wheat Yangmai13 (Triticum aestivum L.) at field and regional levels in China. Winter wheat was grown in artificial shading and open-top-chamber environments. Treatment 1 (T1, i.e., 60% shading with an enhanced ozone of 100±9 ppb), Treatment 2 (T2, i.e., 20% shading with an enhanced ozone of 100±9 ppb), and Control Check Treatment (CK, i.e., no shading with an enhanced ozone of 100±9 ppb), with two plots under each, were established to investigate the response of winter wheat under elevated ozone concentrations and varying solar irradiance. At the field level, linear temporal relationships between dry matter loss and cumulative stomatal ozone uptake were first established through a parameterized stomatal-flux model. At the regional level, ozone concentrations and meteorological variables, including solar irradiance, were simulated using the WRF-CMAQ model (i.e., a meteorology and air quality modeling system). These variables were then used to estimate cumulative stomatal ozone uptake for the four major winter wheat-growing provinces. The regional-level cumulative ozone uptake was then used as the independent variable in field data-based regression models to predict dry matter loss over space and time. Field-level results showed that over 85% (T1: R(2) = 0.85 & T2: R(2) = 0.89) of variation in dry matter loss was explained by cumulative ozone uptake. Dry matter was reduced by 3.8% in T1 and 2.2% in T2 for each mmol O3·m(-2) of cumulative ozone uptake. At the regional level, dry matter loss in winter

  18. The Effect of Elevated Ozone Concentrations with Varying Shading on Dry Matter Loss in a Winter Wheat-Producing Region in China

    PubMed Central

    Xu, Jingxin; Zheng, Youfei; He, Yuhong; Wu, Rongjun; Mai, Boru; Kang, Hanqing

    2016-01-01

    Surface-level ozone pollution causes crop production loss by directly reducing healthy green leaf area available for carbon fixation. Ozone and its precursors also affect crop photosynthesis indirectly by decreasing solar irradiance. Pollutants are reported to have become even more severe in Eastern China over the last ten years. In this study, we investigated the effect of a combination of elevated ozone concentrations and reduced solar irradiance on a popular winter wheat Yangmai13 (Triticum aestivum L.) at field and regional levels in China. Winter wheat was grown in artificial shading and open-top-chamber environments. Treatment 1 (T1, i.e., 60% shading with an enhanced ozone of 100±9 ppb), Treatment 2 (T2, i.e., 20% shading with an enhanced ozone of 100±9 ppb), and Control Check Treatment (CK, i.e., no shading with an enhanced ozone of 100±9 ppb), with two plots under each, were established to investigate the response of winter wheat under elevated ozone concentrations and varying solar irradiance. At the field level, linear temporal relationships between dry matter loss and cumulative stomatal ozone uptake were first established through a parameterized stomatal-flux model. At the regional level, ozone concentrations and meteorological variables, including solar irradiance, were simulated using the WRF-CMAQ model (i.e., a meteorology and air quality modeling system). These variables were then used to estimate cumulative stomatal ozone uptake for the four major winter wheat-growing provinces. The regional-level cumulative ozone uptake was then used as the independent variable in field data-based regression models to predict dry matter loss over space and time. Field-level results showed that over 85% (T1: R2 = 0.85 & T2: R2 = 0.89) of variation in dry matter loss was explained by cumulative ozone uptake. Dry matter was reduced by 3.8% in T1 and 2.2% in T2 for each mmol O3·m-2 of cumulative ozone uptake. At the regional level, dry matter loss in winter wheat

  19. The Effect of Elevated Ozone Concentrations with Varying Shading on Dry Matter Loss in a Winter Wheat-Producing Region in China.

    PubMed

    Xu, Jingxin; Zheng, Youfei; He, Yuhong; Wu, Rongjun; Mai, Boru; Kang, Hanqing

    2016-01-01

    Surface-level ozone pollution causes crop production loss by directly reducing healthy green leaf area available for carbon fixation. Ozone and its precursors also affect crop photosynthesis indirectly by decreasing solar irradiance. Pollutants are reported to have become even more severe in Eastern China over the last ten years. In this study, we investigated the effect of a combination of elevated ozone concentrations and reduced solar irradiance on a popular winter wheat Yangmai13 (Triticum aestivum L.) at field and regional levels in China. Winter wheat was grown in artificial shading and open-top-chamber environments. Treatment 1 (T1, i.e., 60% shading with an enhanced ozone of 100±9 ppb), Treatment 2 (T2, i.e., 20% shading with an enhanced ozone of 100±9 ppb), and Control Check Treatment (CK, i.e., no shading with an enhanced ozone of 100±9 ppb), with two plots under each, were established to investigate the response of winter wheat under elevated ozone concentrations and varying solar irradiance. At the field level, linear temporal relationships between dry matter loss and cumulative stomatal ozone uptake were first established through a parameterized stomatal-flux model. At the regional level, ozone concentrations and meteorological variables, including solar irradiance, were simulated using the WRF-CMAQ model (i.e., a meteorology and air quality modeling system). These variables were then used to estimate cumulative stomatal ozone uptake for the four major winter wheat-growing provinces. The regional-level cumulative ozone uptake was then used as the independent variable in field data-based regression models to predict dry matter loss over space and time. Field-level results showed that over 85% (T1: R(2) = 0.85 & T2: R(2) = 0.89) of variation in dry matter loss was explained by cumulative ozone uptake. Dry matter was reduced by 3.8% in T1 and 2.2% in T2 for each mmol O3·m(-2) of cumulative ozone uptake. At the regional level, dry matter loss in winter

  20. Shade use by small groups of domestic horses in a hot, sunny environment.

    PubMed

    Holcomb, K E; Tucker, C B; Stull, C L

    2015-11-01

    Horses in the United States are commonly managed in outside pens or pastures in small groups. Limited research on shade use by domestic horses housed singly in individual pens has shown benefits and a preference for using available shade. The objective of this study was to examine the amount of shade use and the behavioral and physiological responses of small groups of horses when housed with access to shade (SH) and without access to shade (SUN). Thirty-six horses were randomized into 3 consecutive trials using 3 horses per group and 4 groups per trial. Groups experienced 5 d in each treatment in a crossover design. Weather factors were measured with automated sensors 24 h/d throughout the study. The mean afternoon ambient temperature was 31.0°C with relative humidity of 32%. Rectal temperature, respiration rate, and skin temperature were recorded at 1000, 1330, and 1900 h daily. Venous blood samples were obtained on Days 0 and 5 to measure serum cortisol, the neutrophil:lymphocyte ratio, and hematocrit. Behavioral observations for presence in shade, standing near or away from water, locomotion, and foraging were recorded at 5-min intervals from 1400 to 1900 h daily. Insect avoidance behaviors were recorded hourly during that same time period for 1 min/horse. Horses in the SH treatment were observed using shade in 7.1% of observations between 1400 and 1900 h, and behavioral differences were observed between the SH and SUN treatments. When in the SUN treatment, horses stood near the water troughs more (18.5 vs. 14.2% of observations; = 0.029) and foraged less (29.3 vs. 33.8% of observations; < 0.001) than when in the SH treatment. There were no treatment differences for other behaviors or for physiological measures ( > 0.05). Provision of shade structures accessible to groups of mature, healthy horses in hot, sunny environments should be considered in developing future guidelines for best management practices for horses.

  1. Shade-induced stem elongation in rice seedlings: Implication of tissue-specific phytohormone regulation.

    PubMed

    Liu, Huihui; Yang, Chuanwei; Li, Lin

    2016-07-01

    A better understanding of shade avoidance syndrome (SAS) is an urgent need because of its effect on energy reallocation. Leverage-related mechanism in crops is of potential economic interest for agricultural applications. Here we report the SAS phenotype at tissue level rice seedlings. Tissue-specific RNA-sequencing indicates auxin plays different roles between coleoptile and the first leaf. Phenotypes of wild type treated by gibberellin and brassinosteroid biosynthesis inhibitors and of related mutants suggest these two hormones positively regulate SAS. Our work reveals the diversity of hormone responses in different organs and different species in shade conditions. PMID:26888633

  2. Processing techniques for the production of an experimental computer-generated shaded-relief map

    USGS Publications Warehouse

    Judd, Damon D.

    1986-01-01

    The data consisted of forty-eight 1° by 1° blocks of resampled digital elevation model (DEM) data. These data were digitally mosaicked and assigned colors based on intervals of elevation values. The color-coded data set was then used to create a shaded-relief image that was photographically composited with cartographic line information to produce a shaded-relief map. The majority of the processing was completed at the National Mapping Division EROS Data Center in Sioux Falls, South Dakota.

  3. Comparison analysis of self-shading loss in pedestal and carousel tracker systems

    NASA Astrophysics Data System (ADS)

    Ijiro, Toshikazu; Yamada, Noboru

    2013-09-01

    This paper describes the results of a self-shading loss analysis of a high concentration photovoltaic (HCPV) plant based on pedestal and carousel solar tacking systems. To determine the best possible tracker array configuration to minimize self-shading loss, a multiobjective genetic algorithm (MOGA) was used with a theoretical shadow model and cloudless solar spectrum model. As a result of MOGA optimization, the trade-off between land-use efficiency and the capacity factor in the optimized tracker arrays was characterized and compared.

  4. Anaglyph: Shaded Relief and Height as Brightness, Iturralde Structure, Bolivia

    NASA Technical Reports Server (NTRS)

    2002-01-01

    An 8-kilometer (5-mile) wide crater of possible impact origin is shown in this anaglyph view of an isolated part of the Bolivian Amazon derived from a Shuttle Radar Topography Mission (SRTM) elevation model. The circular feature at the center 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.

    Thick vegetation in part defines the surface that the SRTM radar sees as it maps the terrain. Much of the local 'topography' in this area is a measure of tree height (typically up to 13 meters, or 40 feet). This effect is easily seen here, where the ground surface relief is very low. Interpretative separation of the ground surface and vegetative features typically relies upon recognition of their characteristic patterns.

    This anaglyph was created by deriving an image of the terrain from the SRTM data, draping it back over the SRTM elevation model, and then generating two differing perspectives, one for each eye. The terrain image depicts a combination of topographic shading (north slopes bright) and topographic height (higher elevations bright). When

  5. Microenvironmental changes and plant responses due to shading and wind deflectio by solar collectors: a simulation study

    SciTech Connect

    Patten, D.T.; Smith, S.D.

    1980-11-01

    The potential microenvironmental changes at the ground surface beneath arrays of solar mirrors or collectors were investigated in a Sonoran Desert ecosystem, utilizing a simulated array of plywood panels. The simulated array consisted of twelve panels designed to exhibit a similar shape, tilt, and spacing as is expected to occur in heliostat fields of solar thermal facilities or in arrays of photovoltaic collectors. The experimental design in the study was based on comparing two microsites in the simulated array versus the open desert. Presence of the panels results in up to a 90% reduction in solar radiance during the midday period, with microsites beneath each panel receiving about 14% of the open desert irradiance over the whole day. The array of panels also effected a 14% to 60% reduction in monthly accumulated wind flow in the center of the array. The combination of reduced radiant energy input and wind deflection resulted in significantly reduced surface and soil temperatures in the heavily shaded sites, and moderately reduced surface and soil temperatures in the sunny microsites. Plant responses to a cooler, moister environment were: (1) higher diversity and survival of winter spring annuals; (2) proliferation of C/sub 3/ annuals in the summer flora versus the more typical C/sub 4/ annuals in the open; (3) greater new shoot production of shrubs; (4) greater gross photosynthesis and stomatal conductance of the two shrub species in the warm dry season, but not in the cool wet season; (5) increased leaf retention and reduction in the typical leaf polymorphic character into the dry season of the drought deciduous Ambrosia deltoidea; and, (6) invasion of the heavily shaded areas of the array by a pseudo-riparian species, Baccharis sarothroides. (WHK)

  6. Access to shade changes behavioral and physiological attributes of dairy cows during the hot season in the subtropics.

    PubMed

    Vizzotto, E F; Fischer, V; Thaler Neto, A; Abreu, A S; Stumpf, M T; Werncke, D; Schmidt, F A; McManus, C M

    2015-09-01

    The effect of shade on behavior and physiological attributes of grazing cows in a high altitude subtropical zone is not well established. This work aimed to investigate how social and ingestive behaviors, as well as physiological and other attributes of dairy cows such as milk production, change in a subtropical environment during the hot season either with or without free access to shade. Fourteen lactating cows were kept on pasture either with no shade or with free access to shade for 5 days and their behavior was recorded with instantaneous scan sampled every 10 min, from sunrise, 0530 h (Greenwich mean time, GMT-0200 h) to sunset, 2100 h (GMT-0200 h). Behavior traits included (1) time spent in activities such as grazing, ruminating, resting, lying, standing, walking, seeking shade and staying in the proximity to the water trough and (2) number of events such as water ingestion, aggressive interactions, as well as competition for shade and water. Physiological attributes such as heart and respiratory rates, rectal temperature, number of rumen movements, panting score, as well as milk yield, were evaluated. Time spent in behavioral activities, number of behavioral events and physiological attributes varied between groups (with and without access to shade). Cows with no shade showed increased respiratory and heart rates and panting score at 1300 h, higher values for time of permanence near the water trough, number of competition and aggression events for shade. On the other hand, they showed lower values for time spent resting while lying, ruminating while standing, seeking shade. Access to shade did not change time spent lying, standing, walking with the head up, ruminating while lying, resting while standing, as well as milk yield and number of ruminal movements. Significant interactions between access to shade and days of measurements were detected for time spent walking, ruminating, grazing, resting, number of water ingestion events, competition events near

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

    PubMed

    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

  8. Responses of floodplain forest species to spatially condensed gradients: a test of the flood-shade tolerance tradeoff hypothesis.

    PubMed

    Battaglia, L L; Sharitz, R R

    2006-02-01

    Previous work in southeastern US floodplains led to the hypothesis that a tradeoff between flood and shade tolerance underlies species-specific responses to flooding and light, which drive forest regeneration. In systems where community turnover can occur with small-scale environmental changes, testing this hypothesis requires recognizing that turnover of species along the two gradients can be large relative to the spatial distances involved. We test the tradeoff hypothesis in an old-growth bottomland hardwood forest by (1) comparing shade and moisture profiles of woody juveniles versus random points and (2) using individual-based sampling of woody juveniles to model probability of occurrence in response to distance-to-water table and canopy openness gradients. We found that juveniles of all species combined occupied a similar range of distance-to-water table compared to measurements taken at random points, but average canopy openness above seedlings was significantly higher than at random points. On average, shade-tolerant species, with the exception of Acer rubrum, were found in shaded areas that were also drier, whereas less shade-tolerant taxa, plus A. rubrum, were found in wetter, more open areas, suggesting a tradeoff between flood and shade tolerance. Predictive models of species occurrence, which incorporate the availability of canopy and microtopographic conditions, indicated that three taxa (Fraxinus pennsylvanica, Quercus spp., and Ulmus americana) had patterns consistent with a flood-shade tolerance tradeoff. In contrast, Asimina triloba, Celtis laevigata, and Liquidambar styraciflua had positive responses when the joint stresses of flooding and shade were diminished. A. rubrum appeared to be the most tolerant to both stresses. Our work not only lends support to the flood-shade tradeoff hypothesis but also indicates that a more general model is needed that includes a "flood-shade release" component. We also suggest that responses to small

  9. INFLUENCE OF THE DISTANCE OF THE CURING LIGHT SOURCE AND COMPOSITE SHADE ON HARDNESS OF TWO COMPOSITES

    PubMed Central

    Thomé, Thaís; Steagall, Washington; Tachibana, Arlene; Braga, Sheila Regina Maia; Turbino, Miriam Lacalle

    2007-01-01

    This study evaluated the influence of curing tip distance, shade and filler particle size on Vickers microhardness (VHN) of composite resins. Two composites were tested: Filtek Z250 microhybrid (3M ESPE; shades A1 and A3.5) and Filtek Supreme nanofilled (3M ESPE; shades A1B and A3.5B). For each resin, 42 specimens (5 mm in diameter and 2 mm height) were prepared being 21 for each shade. The specimens were exposed using a 20-second exposure to a quartz-tungsten-halogen light source with an irradiance of approximately 560 mW/cm2, at the following distances: 0 mm (surface contact), 6 mm and 12 mm from composite surface. Effectiveness of cure of different resins, shades and curing distances was determined by measuring the top and bottom hardness (VHN) of specimens using a digital microhardness tester (load: 50 g; dwell time: 45 seconds) 24 hours following curing. The hardness ratio was calculated by dividing VHN of the bottom surface by VHN of top surface. Three-way ANOVA and Tukey's post-hoc test (p<0.05) revealed statistically significant differences for all analyzed factors. As for top hardness, as microhardness ratio (bottom/top), the factors shade, distance and composite filler particle size exerted influence on resin curing. Lighter shade composites (A1 and A1B) showed higher hardness values. At 6 and 12 mm curing tip distances, hardness was lower when compared to 0 mm. The microhybrid composite resin presented higheer hardness, being its microhardness ratio satisfactory only at 0 mm for both shades and at 6 mm for the lighter shade. The nanofilled composite resin did not present satisfactory microhardness at the bottom while the microhybrid composite resin had higher hardness than the nanofilled. Composite's curing tip distance and shade can influence hardness. PMID:19089185

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

    PubMed

    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

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

    PubMed

    Ma, Ren-Yi; Zhang, Jiao-Lin; Cavaleri, Molly A; Sterck, Frank; Strijk, Joeri 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), 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.

  12. Preliminary design of a radiator shading device for a lunar outpost

    NASA Technical Reports Server (NTRS)

    Barron, Carlos; Castro, Norma I.; Phillips, Brian

    1991-01-01

    The National Aeronautics and Space Administration is designing a thermal control system for an outpost to be placed permanently on the Moon. One of the functions of the thermal control system is to reject waste heat, which can be accomplished through a radiator. At the lunar equator and during the lunar midday, an unshaded radiator absorbs more heat than it rejects. This problem can be solved by using a shading device to reduce radiation incident on the radiator. The design team was asked to develop concepts for reducing the radiation incident on the radiator and for deploying the radiator and shade system for a 10 kW and a 25 kW heat rejection system. The design team was also asked to develop the best concepts into preliminary design. From the several alternatives developed by the design team, the best one was selected using a decision matrix. Preliminary design of the best concept include support structure, stress analyses, and thermal performance. In addition, the team developed ideas for removing lunar dust from the shading device. The final design solution consisted of a winged radiator shading system with a rail support structure and a scissors mechanism for deployment. The total radiator area required was calculated to be 389 sq m for the 10 kW heat rejection system and 973 sq m for the 25 kW heat rejection system.

  13. Interactions between carbon sequestration and shade tree diversity in a smallholder coffee cooperative in El Salvador.

    PubMed

    Richards, Meryl Breton; Méndez, V Ernesto

    2014-04-01

    Agroforestry systems have substantial potential to conserve native biodiversity and provide ecosystem services. In particular, agroforestry systems have the potential to conserve native tree diversity and sequester carbon for climate change mitigation. However, little research has been conducted on the temporal stability of species diversity and aboveground carbon stocks in these systems or the relation between species diversity and aboveground carbon sequestration. We measured changes in shade-tree diversity and shade-tree carbon stocks in 14 plots of a 35-ha coffee cooperative over 9 years and analyzed relations between species diversity and carbon sequestration. Carbon sequestration was positively correlated with initial species richness of shade trees. Species diversity of shade trees did not change significantly over the study period, but carbon stocks increased due to tree growth. Our results show a potential for carbon sequestration and long-term biodiversity conservation in smallholder coffee agroforestry systems and illustrate the opportunity for synergies between biodiversity conservation and climate change mitigation. PMID:24283921

  14. Response of container-grown flowering dogwood cultivars to sun/shade production regime, 2015

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flowering dogwood, Cornus florida, ‘Cherokee Brave™’ and ‘Cherokee Princess’ were grown in #5 nursery containers in an amended 100% bark substrate. Treatments were assigned based on exposure time to a full sun/shade condition during the growing season: 1) plants grown in full sun, 2) plants grown in...

  15. Soil heat flux calculation for sunlit and shaded surfaces under row crops: 2. Model Test

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A method to calculate surface soil heat flux (G0) as a function of net radiation to the soil (RN,S) was developed that accounts for positional variability across a row crop interrow. The method divides the interrow into separate sections, which may be shaded, partially sunlit, or fully sunlit, and c...

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

    PubMed Central

    Ma, Ren-Yi; Zhang, Jiao-Lin; Cavaleri, Molly A.; Sterck, Frank; Strijk, Joeri 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), 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. PMID:26461108

  17. Portrayal of Tanning, Clothing Fashion and Shade Use in Australian Women's Magazines, 1987-2005

    ERIC Educational Resources Information Center

    Dixon, Helen; Dobbinson, Suzanne; Wakefield, Melanie; Jamsen, Kris; McLeod, Kim

    2008-01-01

    To examine modelling of outcomes relevant to sun protection in Australian women's magazines, content analysis was performed on 538 spring and summer issues of popular women's magazines from 1987 to 2005. A total of 4949 full-colour images of Caucasian females were coded for depth of tan, extent of clothing cover, use of shade and setting. Logistic…

  18. MTR BUILDING, TRA603. NORTHEAST CORNER, NORTH SIDE SHADED. CAMERA FACING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    MTR BUILDING, TRA-603. NORTHEAST CORNER, NORTH SIDE SHADED. CAMERA FACING SOUTHWEST. NORTH-SIDE PROJECTION IS PLUG STORAGE BUILDING, TRA-657; BUILDING NEXT TO EAST WALL IS AIR COMPRESSOR BUILDING, TRA-626. INL NEGATIVE NO. HD46-43-1. Mike Crane, Photographer, 4/2005 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  19. Ethylene- and Shade-Induced Hypocotyl Elongation Share Transcriptome Patterns and Functional Regulators1[OPEN

    PubMed Central

    Voesenek, Laurentius A.C.J.

    2016-01-01

    Plants have evolved shoot elongation mechanisms to escape from diverse environmental stresses such as flooding and vegetative shade. The apparent similarity in growth responses suggests a possible convergence of the signaling pathways. Shoot elongation is mediated by passive ethylene accumulating to high concentrations in flooded plant organs and by changes in light quality and quantity under vegetation shade. Here, we study hypocotyl elongation as a proxy for shoot elongation and delineate Arabidopsis (Arabidopsis thaliana) hypocotyl length kinetics in response to ethylene and shade. Based on these kinetics, we further investigated ethylene- and shade-induced genome-wide gene expression changes in hypocotyls and cotyledons separately. Both treatments induced a more extensive transcriptome reconfiguration in the hypocotyls compared with the cotyledons. Bioinformatics analyses suggested contrasting regulation of growth promotion- and photosynthesis-related genes. These analyses also suggested an induction of auxin, brassinosteroid, and gibberellin signatures and the involvement of several candidate regulators in the elongating hypocotyls. Pharmacological and mutant analyses confirmed the functional involvement of several of these candidate genes and physiological control points in regulating stress-escape responses to different environmental stimuli. We discuss how these signaling networks might be integrated and conclude that plants, when facing different stresses, utilize a conserved set of transcriptionally regulated genes to modulate and fine-tune growth. PMID:27329224

  20. 15. ARAII Administration building ARA613, west side (in shade) and ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. ARA-II Administration building ARA-613, west side (in shade) and south side. Camera facing northeast. Railings around roof are part of demolition preparations. Ineel photo no. 2-4. - Idaho National Engineering Laboratory, Army Reactors Experimental Area, Scoville, Butte County, ID

  1. Purpose of esthetic risk assessment in prosthetic rehabilitations with gingiva-shade ceramics.

    PubMed

    Viana, Pedro Couto; Kovacs, Zsolt; Correia, André

    2014-01-01

    Esthetic predictability and the possibility to reduce the need for more aggressive surgical interventions have been two strong reasons for the growing acceptance of gingiva shade ceramics in dental treatments. However this type of rehabilitation also has several esthetic constraints. The aim of this paper is to present an assessment system that may serve as a clinician's guideline to clearly identify the risk factors influencing the esthetic result of gum-shade ceramics and, in the end, to grade these clinical situations as high, medium or low esthetic risk. Over several years of clinical experience, the authors have identified different factors that influence the achievement of satisfactory esthetic results using gumshade ceramics: smile line, extension of the prosthetic rehabilitation, anatomical area, vertical and horizontal transition between the prosthesis and the natural gingiva, contact surface, framework material, and color. In conclusion, despite the great applicability of gingiva-shade ceramics in the resolution of clinical cases involving complex architecture of the hard and soft tissues, this procedure should not be considered one free of esthetic risk. There are different factors that should be evaluated when considering the esthetic results with gingiva-shade ceramics.

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

    PubMed

    Ma, Ren-Yi; Zhang, Jiao-Lin; Cavaleri, Molly A; Sterck, Frank; Strijk, Joeri 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), 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. PMID:26461108

  3. Diseases of Ornamental and Shade Trees, Shrubs, Vines, and Ground Covers.

    ERIC Educational Resources Information Center

    Nichols, Lester P.

    This agriculture extension service publication from Pennsylvania State University covers the identification and control of common ornamental trees, shrubs, and ground cover diseases. The publication is divided into sections. The first section discusses the diseases of ornamental and shade trees, including general diseases and diseases of specific…

  4. Responses to shading of naturalized and non-naturalized exotic woody species

    PubMed Central

    Feng, Yanhao; van Kleunen, Mark

    2014-01-01

    Background and Aims Recent studies have suggested that responses to shading gradients may play an important role in establishment success of exotic plants, but hitherto few studies have tested this. Therefore, a common-garden experiment was conducted using multiple Asian woody plant species that were introduced to Europe >100 years ago in order to test whether naturalized and non-naturalized species differ in their responses to shading. Specifically, a test was carried out to determine whether naturalized exotic woody species maintained better growth under shaded conditions, and whether they expressed greater (morphological and physiological) adaptive plasticity in response to shading, relative to non-naturalized species. Methods Nineteen naturalized and 19 non-naturalized exotic woody species were grown under five light levels ranging from 100 to 7 % of ambient light. For all plants, growth performance (i.e. biomass), morphological and CO2 assimilation characteristics were measured. For the CO2 assimilation characteristics, CO2 assimilation rate was measured at 1200 μmol m–2 s–1 (i.e. saturated light intensity, A1200), 50 μmol m–2 s–1 (i.e. low light intensity, A50) and 0 μmol m–2 s–1 (A0, i.e. dark respiration). Key Results Overall, the naturalized and non-naturalized species did not differ greatly in biomass production and measured morphological and CO2 assimilation characteristics across the light gradient. However, it was found that naturalized species grew taller and reduced total leaf area more than non-naturalized species in response to shading. It was also found that naturalized species were more capable of maintaining a high CO2 assimilation rate at low light intensity (A50) when grown under shading. Conclusions The results indicate that there is no clear evidence that the naturalized species possess a superior response to shading over non-naturalized species, at least not at the early stage of their growth. However, the higher CO2

  5. Effects of shade on plant growth and flower quality in the herbaceous peony (Paeonia lactiflora Pall.).

    PubMed

    Zhao, Daqiu; Hao, Zhaojun; Tao, Jun

    2012-12-01

    Herbaceous peony (Paeonia lactiflora Pall.) is an important ornamental plant used in urban green spaces, but little is known about whether it can grow in a shaded environment or understory. In this study, effects of shade on plant growth and flower quality in the herbaceous peony were investigated. The results showed that P. lactiflora morphology parameters, including plant height, leaf number, stem diameter, branch number, node number and plant crown width, were higher in plants grown with sun exposure compared to those grown in shade; however, opposite trends were observed for the top and middle leaf areas of the plant. Compared with sun exposure, shade decreased P. lactiflora photosynthetic capacity, light saturation point (LSP) and light compensation point (LCP) and increased the apparent quantum yield (AQY), mainly due to declined stomatal conduction (Gs). These decreases caused the soluble sugar, soluble protein and malondialdehyde (MDA) contents to decline, which led to delayed initial flowering date, prolonged flowering time, reduced flower fresh weight, increased flower diameter and faded flower color. Through cloning and expression analysis of anthocyanin biosynthetic genes, we determined that the fading of flower color was the result of reduced anthocyanin content, which was caused by the combined activity of anthocyanin biosynthesis genes and, in particular, of the upstream phenylalanine ammonialyase gene (PlPAL) and chalcone synthase gene (PlCHS). These results could provide us with a theoretical basis for further application of P. lactiflora in the greening of urban spaces and an understanding of the mechanisms behind the changes induced by shade.

  6. Shading facilitates sessile invertebrate dominance in the rocky subtidal Gulf of Maine.

    PubMed

    Miller, Robert J; Etter, Ron J

    2008-02-01

    Dramatic shifts in community composition occur between vertical and horizontal rocky surfaces in subtidal environments worldwide, yet the forces mediating this transition are poorly understood. Vertical rock walls are often covered by lush, diverse communities of sessile suspension-feeding invertebrates, while adjacent horizontal substrates are dominated by algae, or corals in the tropics. Multiple factors, including light, sedimentation, water flow, and predation have been proposed to explain this pattern, but experimental tests of these hypotheses are lacking. We manipulated light level and predation to test whether variation in these mechanisms could be responsible for the shift in composition of sessile communities between vertical and horizontal surfaces in the rocky subtidal Gulf of Maine. Shaded horizontally oriented granite plots were dominated by invertebrates (e.g., ascidians, barnacles, bryozoans) after 25 months. Unshaded plots were dominated by macroalgae, which was virtually absent in shaded plots. Exclusion of grazers with cages had no effect on percent cover of invertebrates or algae. Preferential settlement of invertebrate larvae to shaded plots, due to larval behaviors such as negative phototaxis, did not seem to play a role. Shading likely affects post-settlement mortality of invertebrates by alleviating competition for space with algae, although greater abundance of micropredators in algal-dominated communities could also be important. Communities on shaded plots lacked many taxa present on natural wall communities, likely due to greater disturbance on horizontal substrates and/or lack of sufficient time for colonization of these taxa. These results suggest that light plays a key role in controlling the structure, composition, and function of shallow subtidal communities.

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

    PubMed

    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.

  8. Duration and intensity of shade differentially affects mycorrhizal growth- and phosphorus uptake responses of Medicago truncatula

    PubMed Central

    Konvalinková, Tereza; Püschel, David; Janoušková, Martina; Gryndler, Milan; Jansa, Jan

    2015-01-01

    Plant and fungal partners in arbuscular mycorrhizal symbiosis trade mineral nutrients for carbon, with the outcome of this relationship for plant growth and nutrition being highly context-dependent and changing with the availability of resources as well as with the specific requirements of the different partners. Here we studied how the model legume Medicago truncatula, inoculated or not with a mycorrhizal fungus Rhizophagus irregularis, responded to a gradient of light intensities applied over different periods of time, in terms of growth, phosphorus nutrition and the levels of root colonization by the mycorrhizal fungus. Short-term (6 d) shading, depending on its intensity, resulted in a rapid decline of phosphorus uptake to the shoots of mycorrhizal plants and simultaneous accumulation of phosphorus in the roots (most likely in the fungal tissues), as compared to the non-mycorrhizal controls. There was, however, no significant change in the levels of mycorrhizal colonization of roots due to short-term shading. Long-term (38 d) shading, depending on its intensity, provoked a multitude of plant compensatory mechanisms, which were further boosted by the mycorrhizal symbiosis. Mycorrhizal growth- and phosphorus uptake benefits, however, vanished at 10% of the full light intensity applied over a long-term. Levels of root colonization by the mycorrhizal fungus were significantly reduced by long-term shading. Our results indicate that even short periods of shade could have important consequences for the functioning of mycorrhizal symbiosis in terms of phosphorus transfer between the fungus and the plants, without any apparent changes in root colonization parameters or mycorrhizal growth response, and call for more focused research on temporal dynamics of mycorrhizal functioning under changing environmental conditions. PMID:25763002

  9. INFLUENCE OF LIGHT CURING SOURCE ON MICROHARDNESS OF COMPOSITE RESINS OF DIFFERENT SHADES

    PubMed Central

    BRISO, André Luiz Fraga; FEDEL, Tânia Maria; PEREIRA, Sibéria de Morais; MAURO, Sílvio José; SUNDFELD, Renato Herman; SUNDEFELD, Maria Lúcia Marçal Mazza

    2006-01-01

    Introduction: The evolution of light curing units can be noticed by the different systems recently introduced. The technology of LED units promises longer lifetime, without heating and with production of specific light for activation of camphorquinone. However, further studies are still required to check the real curing effectiveness of these units. Purpose: This study evaluated the microhardness of 4 shades (B-0.5, B-1, B-2 and B-3) of composite resin Filtek Z-250 (3M ESPE) after light curing with 4 light sources, being one halogen (Ultralux – Dabi Atlante) and three LED (Ultraled – Dabi Atlante, Ultrablue – DMC and Elipar Freelight – 3M ESPE). Methods: 192 specimens were distributed into 16 groups, and materials were inserted in a single increment in cylindrical templates measuring 4mm x 4mm and light cured as recommended by the manufacturer. Then, they were submitted to microhardness test on the top and bottom aspects of the cylinders. Results: The hardness values achieved were submitted to analysis of variance and to Tukey test at 5% confidence level. It was observed that microhardness of specimens varied according to the shade of the material and light sources employed. The LED appliance emitting greater light intensity provided the highest hardness values with shade B-0.5, allowing the best curing. On the other hand, appliances with low light intensity were the least effective. It was also observed that the bottom of specimens was more sensitive to changes in shade. Conclusion: Light intensity of LED light curing units is fundamental for their good functioning, especially when applied in resins with darker shades. PMID:19089023

  10. The effects of zilpaterol hydrochloride and shade on blood metabolites of finishing beef steers.

    PubMed

    Hales, K E; Foote, A P; Jones, S A; Shackelford, S D; Boyd, B M; Erickson, G E

    2016-07-01

    The effects of feeding zilpaterol hydrochloride (ZH) and shade were evaluated on blood metabolites in finishing beef steers ( = 480). Cattle were fed 0 or 8.33 mg/kg of diet DM ZH for 21 d with a 3- or 4-d withdrawal before harvest and were housed in open or shaded pens. Blood samples were collected the day before ZH was fed and on the day the cattle were shipped to the commercial abattoir. Lactate concentration was not different between cattle fed ZH in open or shaded pens ( = 0.12). Nonetheless, a tendency for a diet × time interaction was detected for lactate concentration ( = 0.09), in which it was greater in cattle fed the control diet in open pens before being fed ZH. Cortisol concentration was less before and after ZH was fed ( = 0.01). Glucose was greater for cattle fed the control diet than cattle fed ZH for 21 d ( = 0.03). Cattle fed in open vs. shaded pens did not differ in glucose concentration ( = 0.12), whereas glucose concentrations were greater before ZH was fed than after ( = 0.02). In contrast, plasma urea nitrogen (PUN) concentration was not different in response to diet ( = 0.24), housing type ( = 0.65), or before vs. after being fed ZH ( = 0.60). Lactate concentrations were not different across diet or shade treatments before ZH was fed, whereas after ZH, lactate concentrations were greater in control cattle than cattle fed ZH. Additionally, cortisol was less after feeding ZH. Glucose was greater before than after feeding ZH.

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

    PubMed

    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. PMID:26263660

  12. The effects of zilpaterol hydrochloride and shade on blood metabolites of finishing beef steers.

    PubMed

    Hales, K E; Foote, A P; Jones, S A; Shackelford, S D; Boyd, B M; Erickson, G E

    2016-07-01

    The effects of feeding zilpaterol hydrochloride (ZH) and shade were evaluated on blood metabolites in finishing beef steers ( = 480). Cattle were fed 0 or 8.33 mg/kg of diet DM ZH for 21 d with a 3- or 4-d withdrawal before harvest and were housed in open or shaded pens. Blood samples were collected the day before ZH was fed and on the day the cattle were shipped to the commercial abattoir. Lactate concentration was not different between cattle fed ZH in open or shaded pens ( = 0.12). Nonetheless, a tendency for a diet × time interaction was detected for lactate concentration ( = 0.09), in which it was greater in cattle fed the control diet in open pens before being fed ZH. Cortisol concentration was less before and after ZH was fed ( = 0.01). Glucose was greater for cattle fed the control diet than cattle fed ZH for 21 d ( = 0.03). Cattle fed in open vs. shaded pens did not differ in glucose concentration ( = 0.12), whereas glucose concentrations were greater before ZH was fed than after ( = 0.02). In contrast, plasma urea nitrogen (PUN) concentration was not different in response to diet ( = 0.24), housing type ( = 0.65), or before vs. after being fed ZH ( = 0.60). Lactate concentrations were not different across diet or shade treatments before ZH was fed, whereas after ZH, lactate concentrations were greater in control cattle than cattle fed ZH. Additionally, cortisol was less after feeding ZH. Glucose was greater before than after feeding ZH. PMID:27482680

  13. Shades of Green: Growing Environmentalism through Art Education

    ERIC Educational Resources Information Center

    Inwood, Hilary

    2010-01-01

    As a university-based art educator inspired by the efforts of environmental artists, the author has been working to share their achievements with students and teachers through eco-art education. She aims to continue this work through this article by sharing recent developments in this emerging field of inquiry. In hopes of encouraging art…

  14. Color, Race, and English Language Teaching: Shades of Meaning

    ERIC Educational Resources Information Center

    Curtis, Andy, Ed.; Romney, Mary, Ed.

    2006-01-01

    The unique contribution of this book is to bring together Critical Race Theory and narrative inquiry and apply them specifically to a largely overlooked area of experience within the field of TESOL: What does it mean to be a TESOL professional of color? To address this question, TESOL professionals of color from all over the world, representing a…

  15. Assessment of the Potential to Achieve very Low Energy Use in Public Buildings in China with Advanced Window and Shading Systems

    SciTech Connect

    Lee, Eleanor; Pang, Xiufeng; McNeil, Andrew; Hoffmann, Sabine; Thanachareonkit, Anothai; Li, Zhengrong; Ding, Yong

    2015-05-29

    As rapid growth in the construction industry continues to occur in China, the increased demand for a higher standard living is driving significant growth in energy use and demand across the country. Building codes and standards have been implemented to head off this trend, tightening prescriptive requirements for fenestration component measures using methods similar to the U.S. model energy code American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 90.1. The objective of this study is to (a) provide an overview of applicable code requirements and current efforts within China to enable characterization and comparison of window and shading products, and (b) quantify the load reduction and energy savings potential of several key advanced window and shading systems, given the divergent views on how space conditioning requirements will be met in the future. System-level heating and cooling loads and energy use performance were evaluated for a code-compliant large office building using the EnergyPlus building energy simulation program. Commercially-available, highly-insulating, low-emittance windows were found to produce 24%–66% lower perimeter zone HVAC electricity use compared to the mandated energy-efficiency standard in force (GB 50189-2005) in cold climates like Beijing. Low-e windows with operable exterior shading produced up to 30%–80% reductions in perimeter zone HVAC electricity use in Beijing and 18%–38% reductions in Shanghai compared to the standard. The economic context of China is unique since the cost of labor and materials for the building industry is so low. Broad deployment of these commercially available technologies with the proper supporting infrastructure for design, specification, and verification in the field would enable significant reductions in energy use and greenhouse gas emissions in the near term.

  16. Assessment of the Potential to Achieve very Low Energy Use in Public Buildings in China with Advanced Window and Shading Systems

    DOE PAGES

    Lee, Eleanor; Pang, Xiufeng; McNeil, Andrew; Hoffmann, Sabine; Thanachareonkit, Anothai; Li, Zhengrong; Ding, Yong

    2015-05-29

    As rapid growth in the construction industry continues to occur in China, the increased demand for a higher standard living is driving significant growth in energy use and demand across the country. Building codes and standards have been implemented to head off this trend, tightening prescriptive requirements for fenestration component measures using methods similar to the U.S. model energy code American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 90.1. The objective of this study is to (a) provide an overview of applicable code requirements and current efforts within China to enable characterization and comparison of window and shading products,more » and (b) quantify the load reduction and energy savings potential of several key advanced window and shading systems, given the divergent views on how space conditioning requirements will be met in the future. System-level heating and cooling loads and energy use performance were evaluated for a code-compliant large office building using the EnergyPlus building energy simulation program. Commercially-available, highly-insulating, low-emittance windows were found to produce 24%–66% lower perimeter zone HVAC electricity use compared to the mandated energy-efficiency standard in force (GB 50189-2005) in cold climates like Beijing. Low-e windows with operable exterior shading produced up to 30%–80% reductions in perimeter zone HVAC electricity use in Beijing and 18%–38% reductions in Shanghai compared to the standard. The economic context of China is unique since the cost of labor and materials for the building industry is so low. Broad deployment of these commercially available technologies with the proper supporting infrastructure for design, specification, and verification in the field would enable significant reductions in energy use and greenhouse gas emissions in the near term.« less

  17. Separate localization of light signal perception for sun or shade type chloroplast and palisade tissue differentiation in Chenopodium album.

    PubMed

    Yano, S; Terashima, I

    2001-12-01

    Physiological and ecological characteristics of sun and shade leaves have been compared in detail, but their developmental processes, in particular their light sensory mechanisms, are still unknown. This study compares the development of sun and shade leaves of Chenopodium album L., paying special attention to the light sensory site. We hypothesized that mature leaves sense the light environment, and that this information determines anatomy of new leaves. To examine this hypothesis, we shaded plants partially. In the low-light apex treatment (LA), the shoot apex with developing leaves was covered by a cap made of a shading screen and received photosynthetically active photon flux density (PPFD) of 60 micromol m(-2 )s(-1), while the remaining mature leaves were exposed to 360 micromol m(-2 )s(-1). In the high-light apex treatment (HA), the apex was exposed while the mature leaves were covered by a shade screen. After these treatments for 6 d, we analyzed leaf anatomy and chloroplast ultrastructure. The anatomy of LA leaves with a two-layered palisade tissue was similar to that of sun leaves, while their chloroplasts were shade-type with thick grana. The anatomy of HA leaves and shade leaves was similar and both had one-layered palisade tissue, while chloroplasts of HA leaves were sun-type having thin grana. These results clearly demonstrate that new leaves differentiate depending on the light environment of mature leaves, while chloroplasts differentiate depending on the local light environment.

  18. Multi-waveband solar irradiance on tree-shaded vertical and horizontal surfaces: cloud-free and partly cloudy skies.

    PubMed

    Grant, R H; Heisler, G M

    2001-01-01

    Irradiance measurements of short wave (SW), photosynthetically active (PAR), ultraviolet-A (UVA) and ultraviolet-B (UVB) solar radiations were made on horizontal and vertical surfaces in the shade of trees under cloud-free and partly cloudy skies. All measurements were referenced to the irradiance of a horizontal surface above the canopy. For horizontal shaded surfaces under cloud-free skies, the values of the ratio (Rh) of below- to above-canopy horizontal irradiance were similar for the UVA and UVB wavebands and for the SW and PAR wavebands. However, Rh for the UV wavebands differed from that for the PAR and SW wavebands. Overall, values of Rh in the shade typically varied as PAR < SW < UVA < UVB. The irradiance ratios for vertical surface in the shade typically varied as UVB > UVA = SW > PAR. In absolute terms, UVB irradiance (Ih) on tree-shaded horizontal surfaces increased relative to a cloud-free sky when a translucent cirroform cloud was in front of the sun, but decreased when the cloud was in a region of sky away from the sun. Translucent cirroform cloud cover also tended to decrease the UVB irradiance (Iv) for a shaded vertical surface (either facing the sun or south) relative to that under cloud-free skies, regardless of where the clouds were in the sky. In all other wavebands the shaded Ih and Iv increased under translucent cirroform cloud cover relative to cloud-free skies, regardless of where the clouds were in the sky.

  19. Multi-waveband solar irradiance on tree-shaded vertical and horizontal surfaces: cloud-free and partly cloudy skies.

    PubMed

    Grant, R H; Heisler, G M

    2001-01-01

    Irradiance measurements of short wave (SW), photosynthetically active (PAR), ultraviolet-A (UVA) and ultraviolet-B (UVB) solar radiations were made on horizontal and vertical surfaces in the shade of trees under cloud-free and partly cloudy skies. All measurements were referenced to the irradiance of a horizontal surface above the canopy. For horizontal shaded surfaces under cloud-free skies, the values of the ratio (Rh) of below- to above-canopy horizontal irradiance were similar for the UVA and UVB wavebands and for the SW and PAR wavebands. However, Rh for the UV wavebands differed from that for the PAR and SW wavebands. Overall, values of Rh in the shade typically varied as PAR < SW < UVA < UVB. The irradiance ratios for vertical surface in the shade typically varied as UVB > UVA = SW > PAR. In absolute terms, UVB irradiance (Ih) on tree-shaded horizontal surfaces increased relative to a cloud-free sky when a translucent cirroform cloud was in front of the sun, but decreased when the cloud was in a region of sky away from the sun. Translucent cirroform cloud cover also tended to decrease the UVB irradiance (Iv) for a shaded vertical surface (either facing the sun or south) relative to that under cloud-free skies, regardless of where the clouds were in the sky. In all other wavebands the shaded Ih and Iv increased under translucent cirroform cloud cover relative to cloud-free skies, regardless of where the clouds were in the sky. PMID:11202362

  20. The regulation of cell wall extensibility during shade avoidance: a study using two contrasting ecotypes of Stellaria longipes.

    PubMed

    Sasidharan, Rashmi; Chinnappa, C C; Voesenek, Laurentius A C J; Pierik, Ronald

    2008-11-01

    Shade avoidance in plants involves rapid shoot elongation to grow toward the light. Cell wall-modifying mechanisms are vital regulatory points for control of these elongation responses. Two protein families involved in cell wall modification are expansins and xyloglucan endotransglucosylase/hydrolases. We used an alpine and a prairie ecotype of Stellaria longipes differing in their response to shade to study the regulation of cell wall extensibility in response to low red to far-red ratio (R/FR), an early neighbor detection signal, and dense canopy shade (green shade: low R/FR, blue, and total light intensity). Alpine plants were nonresponsive to low R/FR, while prairie plants elongated rapidly. These responses reflect adaptation to the dense vegetation of the prairie habitat, unlike the alpine plants, which almost never encounter shade. Under green shade, both ecotypes rapidly elongate, showing that alpine plants can react only to a deep shade treatment. Xyloglucan endotransglucosylase/hydrolase activity was strongly regulated by green shade and low blue light conditions but not by low R/FR. Expansin activity, expressed as acid-induced extension, correlated with growth responses to all light changes. Expansin genes cloned from the internodes of the two ecotypes showed differential regulation in response to the light manipulations. This regulation was ecotype and light signal specific and correlated with the growth responses. Our results imply that elongation responses to shade require the regulation of cell wall extensibility via the control of expansin gene expression. Ecotypic differences demonstrate how responses to environmental stimuli are differently regulated to survive a particular habitat.

  1. Tanning Shade Gradations of Models in Mainstream Fitness and Muscle Enthusiast Magazines: Implications for Skin Cancer Prevention in Men.

    PubMed

    Basch, Corey H; Hillyer, Grace Clarke; Ethan, Danna; Berdnik, Alyssa; Basch, Charles E

    2015-07-01

    Tanned skin has been associated with perceptions of fitness and social desirability. Portrayal of models in magazines may reflect and perpetuate these perceptions. Limited research has investigated tanning shade gradations of models in men's versus women's fitness and muscle enthusiast magazines. Such findings are relevant in light of increased incidence and prevalence of melanoma in the United States. This study evaluated and compared tanning shade gradations of adult Caucasian male and female model images in mainstream fitness and muscle enthusiast magazines. Sixty-nine U.S. magazine issues (spring and summer, 2013) were utilized. Two independent reviewers rated tanning shade gradations of adult Caucasian male and female model images on magazines' covers, advertisements, and feature articles. Shade gradations were assessed using stock photographs of Caucasian models with varying levels of tanned skin on an 8-shade scale. A total of 4,683 images were evaluated. Darkest tanning shades were found among males in muscle enthusiast magazines and lightest among females in women's mainstream fitness magazines. By gender, male model images were 54% more likely to portray a darker tanning shade. In this study, images in men's (vs. women's) fitness and muscle enthusiast magazines portrayed Caucasian models with darker skin shades. Despite these magazines' fitness-related messages, pro-tanning images may promote attitudes and behaviors associated with higher skin cancer risk. To date, this is the first study to explore tanning shades in men's magazines of these genres. Further research is necessary to identify effects of exposure to these images among male readers. PMID:25038234

  2. The effect of type of shade on physiology, behaviour and performance of grazing steers.

    PubMed

    Rovira, P

    2014-03-01

    Research has addressed the issue of type of shade mainly on feedlots and high-producing dairy farms, but more studies are needed on the impact of shade on grazing beef cattle in a low-to-medium plane of nutrition. A 63-day grazing study using 24 British steers (268 ± 4 kg) was undertaken in Uruguay (33°14'S, 54°15'W) to determine the effect of type of artificial shade on tympanic temperature (TT), behaviour and performance during summer. Cattle were allocated to six paddocks with an area of 2.5 ha each (four steers/paddock) continuously grazed. Treatments (two paddocks/treatment) were unshaded (US) and shaded with either 35% (35S) or 80% (80S) blockage of solar radiation. TT was recorded during 12 days placing an automatic device near the tympanic membrane inside the animal's ear. Animal behaviours were measured by live observations of animals every 15 min from 1100 to 1600 h six times during the experimental period. According to the temperature-humidity index (THI), cattle was in the 'normal' category (THI<70, absence of heat stress) during 50% of the time, the rest being exposed to some degree of heat stress including 15% of the time with environmental conditions. Black globe temperature and surface soil temperature decreased as solar protection increased under the shade structure. Steers spent more time under the 80S structure than under the 35S between 1100 and 1600 h (83% and 49% of the time, respectively). Average 24-h TT did not differ among treatments (mean ± s.e. 38.79 ± 0.04ºC). Minimum TT was registered at 0700 h for all treatments (37.92 ± 0.08ºC), whereas maximum TT was reached at 1700 h for both control group (39.73 ± 0.18ºC) and 35% shade (39.48 ± 0.12ºC) and at 1900 h for 80% shade (39.57 ± 0.15ºC). Neither the provision nor the type of shade affected animal performance (0.622 ± 0.060 kg/a per day), indicating the ability of cattle to acclimate and/or compensate for eventually short-term severe heat stress events. The results of this

  3. Influence of cement shade and water storage on the final color of leucite-reinforced ceramics.

    PubMed

    Karaagaclioglu, Lale; Yilmaz, Burak

    2008-01-01

    Leucite-reinforced ceramics have a translucent structure, which may have an advantage when fabricating esthetic restorations. However, the different shades of cement and water storage may adversely affect the final color of translucent restorations. Over time, the final color of a restoration may be significantly affected by the shade of the cement. This in vitro study evaluated the effect of two different cement shades (Vita A1 and A3) and water storage on the final color of leucite-reinforced ceramics over time. Twenty disks of standardized thickness (0.8 mm), diameter (5 mm) and color (shade 110, Chromascope) were prepared from leucite-reinforced glass-ceramic (IPS Empress). Ten freshly extracted human molars were used as the underlying structure, and both the buccal and lingual surfaces of each tooth were prepared with a diamond rotary cutting instrument and flat surfaces were created. Initially, all of the disks were bonded to the flat surfaces of the teeth with a thin layer of bonding agent (Single Bond, 3M Dental Products) to ensure immobilization of the specimens (baseline). The teeth and ceramic specimens were not etched and silanated for easy removal of the specimens. The color of the ceramic specimens was measured with a colorimeter. All disks were gently removed from the tooth surfaces, and 10 specimens (Group A1) were luted to the buccal surfaces of teeth using a dual-polymerizing resin composite cement (Vita A1, Rely X ARC), while the remaining 10 specimens (Group A3) were luted to the lingual surfaces of the teeth with a different shade (Vita A3, Rely X ARC) of the same cement. The final color of the specimens was measured immediately after cementation and at 3-, 30- and 90-day intervals after cementation. Color coordinates L*, a*, b* were recorded. The teeth were stored in 37 degrees C saline solution during measurement intervals. The Mann-Whitney U-test (post-hoc test) was performed to compare the results (alpha=0.05). The color difference of

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

    PubMed Central

    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

  5. Development and implementation of the Clinical Tooth Shade Differentiation Course – an evaluation over 3 years

    PubMed Central

    Olms, Constanze; Haak, Rainer; Jakstat, Holger A.

    2016-01-01

    Objective: Tooth shade differentiation concerns the identification and classification of tooth shades. The objective of this project was to implement the Clinical Tooth Shade Differentiation Course in the preclinical stage of studies and to evaluate the students' perspective over a period of 3 years. Methodology: The course is planned for a duration of 10 weeks with two 45-minute sessions per semester week. The entire attendance time was 10:15 h. 2 lectures of 90 minutes each, 2 seminars of 60 min each and 2 teaching units with the phantom head and role playing took place. In addition to the various parameters of tooth shade, changes in tooth shade and the basics of dental esthetics, clinical procedures for manual and digital tooth shade determination were explained and practiced. 96% (69 of 72) of the students participated in the first evaluation in 2012/2013 (T1), and 68% of these were women. In the following year, 2013/2014 (T2), 92% (45 of 48 students) took part; 62% of these were women and 38% men. The 2014/2015 evaluation (T3) comprised 94% (45 of 48 students). Of these, 67% were women. Results: In the evaluation, the students gave the course a positive grade. The questions in "General/Organization" were given a mean (M) of 1.5 (SD=0.7) in T1 and T2 , and 1.2 (SD=0.3) in T3. The "Overall Assessment" yielded MT1=1.6 (SD=0.6), MT2=1.5 (SD=0.5) and MT3=1.1 (SD=0.3). In T1 and T2, the item "The instructor actively involved the students in the course" was given a mean of 2.1 (SD=0.9), and in T3 a mean of 1.2 (SD=0.5). Conclusions: The course presented here conceptually shows how practical dental skills can be taught in a theoretical and clinical context. Educational objectives from the role of a dental expert were taken from the national competence-based catalog of educational objectives for dentistry and can also be supplemented. The objectives can be transferred to other dental faculties. PMID:26958650

  6. Estimation of sunlit/shaded light-use efficiency of cropland using tower-based multi-angle remote sensing data and eddy covariance flux measurements

    NASA Astrophysics Data System (ADS)

    Fu, D.; Chen, B.; Zhang, L.

    2014-12-01

    The light-use efficiency (LUE, ɛ) is one of critical parameters in the terrestrial ecosystem production studies. However, it is still a challenge how to up-scale LUE from canopy to the landscape/regional scales. One potential solution is to use automated multi-angle tower-based remote sensing platforms, which observe canopy reflectance with high spatial, temporal, spectral and angle resolution. Although some published paper on the LUE in boreal and temperate forests had used continuous multi-angle measurements of the surface reflectance, lack of study in literature investigated the vegetation physiological parameters of cropland using the surface reflectance with high spatio-temporal and high spectral data with multiple angles. To improve our understanding of physiological status of cropland, the maize within the footprint of the Daman Superstation flux tower site of Heihe Watershed Allied Telemetry Experiment Research (HiWATER) was employed in this study. Based on the observed reflectance and flux data, a Bidirectional Reflectance Distribution Function (BRDF) of vegetation index (Photochemical Reflectance Index, PRI and Vegetation Index using the Universal Pattern Decomposition method, VIUPD) at continuous time series was established by integrating of a semi-empirical kernel-driven BRDF model (RossThick-LiSparse), a footprint model (the Simple Analytical Footprint model on Eulerian coordinates for scalar Flux, SAFE-f) and a LUE model. Besides, based on the sky-condition (direct/diffused radiation) data, the relationships between the vegetation index (PRI and VIUPD) and sunlit/shaded LUE under corresponding sky conditions were established. Taking maize field as an example, the measurements were obtained during June to August, 2012. The relationships between PRI and ɛ for sunlit and shaded leaves were: PRIsu=0.06339×log(ɛsu) + 0.04882,PRIsh= 0.02675×log(ɛsh) + 0.01619, where, the subscript su, sh represent sunlit and shaded leaves respectively; p< 0.0001, R2

  7. Estimation of sunlit/shaded light-use efficiency of cropland using tower-based multi-angle remote sensing data and eddy covariance flux measurements

    NASA Astrophysics Data System (ADS)

    Fu, Dongjie; Chen, Baozhang; Zhang, Lifu

    2015-04-01

    The light-use efficiency (LUE) is one of critical parameters in the terrestrial ecosystem production studies. However, it is still a challenge how to up-scale LUE from canopy to the landscape/regional scales. One potential solution is to use automated multi-angle tower-based remote sensing platforms, which observe canopy reflectance with high spatial, temporal, spectral and angle resolution. Although some published paper on the LUE in boreal and temperate forests had used continuous multi-angle measurements of the surface reflectance, lack of study in literature investigated the vegetation physiological parameters of cropland using the surface reflectance with high spatio-temporal and high spectral data with multiple angles. To improve our understanding of physiological status of cropland, the maize within the footprint of the Daman Superstation flux tower site of Heihe Watershed Allied Telemetry Experiment Research (HiWATER) was employed in this study. Based on the observed reflectance and flux data, a Bidirectional Reflectance Distribution Function (BRDF) of vegetation index (Photochemical Reflectance Index, PRI and Vegetation Index using the Universal Pattern Decomposition method, VIUPD) at continuous time series was established by integrating of a semi-empirical kernel-driven BRDF model (RossThick-LiSparse), a footprint model (the Simple Analytical Footprint model on Eulerian coordinates for scalar Flux, SAFE-f) and a LUE model. Besides, based on the sky-condition (direct/diffused radiation) data, the relationships between the vegetation index (PRI and VIUPD) and sunlit/shaded LUE under corresponding sky conditions were established. Taking maize field as an example, the measurements were obtained during June to August, 2012. The relationships between PRI and LUE for sunlit and shaded leaves were: PRIsu=0.06339×log(LUEsu) + 0.04882, PRIsh= 0.02675×log(LUEsh) + 0.01619, where, the subscript su, sh represent sunlit and shaded leaves respectively; p< 0.0001, R2

  8. The epidermis coordinates auxin-induced stem growth in response to shade.

    PubMed

    Procko, Carl; Burko, Yogev; Jaillais, Yvon; Ljung, Karin; Long, Jeff A; Chory, Joanne

    2016-07-01

    Growth of a complex multicellular organism requires coordinated changes in diverse cell types. These cellular changes generate organs of the correct size, shape, and functionality. In plants, the growth hormone auxin induces stem elongation in response to shade; however, which cell types of the stem perceive the auxin signal and contribute to organ growth is poorly understood. Here, we blocked the transcriptional response to auxin within specific tissues to show that auxin signaling is required in many cell types for correct hypocotyl growth in shade, with a key role for the epidermis. Combining genetic manipulations in Arabidopsis thaliana with transcriptional profiling of the hypocotyl epidermis from Brassica rapa, we show that auxin acts in the epidermis in part by inducing activity of the locally acting, growth-promoting brassinosteroid pathway. Our findings clarify cell-specific auxin function in the hypocotyl and highlight the complexity of cell type interactions within a growing organ.

  9. Digital imaging colposcopy: corrected area measurements using shape-from-shading.

    PubMed

    Craine, B L; Craine, E R; O'Toole, C J; Ji, Q

    1998-12-01

    The quantitative measurement of areas on the cervix is of interest to researchers studying the natural history of human papilloma viral lesions. Measurement of areas from images obtained through a colposcope are, however, inherently in error due to the image being a two-dimensional projection of a three-dimensional object. The ability to correct for these errors through use of digital imaging colposcopy and a practical application of a shape from shading algorithm was developed in this study. The shape from shading technique requires empirical measurement of the relationship between observed light intensity and the viewing angle (referred to as a reflection map). It was found that a population mean reflection map provided a correction that was about as accurate as using an individual's own reflection map (making it unnecessary to measure a map for each exam). Digital red filtering of the images increased accuracy and precision of measurement.

  10. Shade Trading: An Emerging Riparian Forest-Based Payment for Ecosystem Services Market in Oregon, USA

    NASA Astrophysics Data System (ADS)

    Guillozet, Kathleen

    2015-10-01

    This paper describes the regulatory and compliance context for Oregon's emerging ecosystem services (ES) market in riparian shade to meet water quality obligations. In Oregon's market as with many other ES programs, contracts and other regulatory documents not only delimit the obligations and liabilities of different parties, but also constitute a primary mechanism through which ES service delivery is measured. Through a review of compliance criteria I find that under Oregon's shade trades, permittees are held to a number of input-based criteria, which essentially affirm that parties comply with predetermined practices and procedures, and one `pseudo output based' criterion, in which ES delivery is estimated through a model. The case presented in the paper critically engages with the challenges of measuring ES and in assessing the outcomes of ES projects. It places these challenges as interrelated and proposes that market designers, policymakers, and other stakeholders should consider explicit efficacy, efficiency, and equity targets.

  11. UV-B detected by the UVR8 photoreceptor antagonizes auxin signaling and plant shade avoidance.

    PubMed

    Hayes, Scott; Velanis, Christos N; Jenkins, Gareth I; Franklin, Keara A

    2014-08-12

    Plants detect different facets of their radiation environment via specific photoreceptors to modulate growth and development. UV-B is perceived by the photoreceptor UV RESISTANCE LOCUS 8 (UVR8). The molecular mechanisms linking UVR8 activation to plant growth are not fully understood, however. When grown in close proximity to neighboring vegetation, shade-intolerant plants initiate dramatic stem elongation to overtop competitors. Here we show that UV-B, detected by UVR8, provides an unambiguous sunlight signal that inhibits shade avoidance responses in Arabidopsis thaliana by antagonizing the phytohormones auxin and gibberellin. UV-B triggers degradation of the transcription factors PHYTOCHROME INTERACTING FACTOR 4 and PHYTOCHROME INTERACTING FACTOR 5 and stabilizes growth-repressing DELLA proteins, inhibiting auxin biosynthesis via a dual mechanism. Our findings show that UVR8 signaling is closely integrated with other photoreceptor pathways to regulate auxin signaling and plant growth in sunlight.

  12. The epidermis coordinates auxin-induced stem growth in response to shade.

    PubMed

    Procko, Carl; Burko, Yogev; Jaillais, Yvon; Ljung, Karin; Long, Jeff A; Chory, Joanne

    2016-07-01

    Growth of a complex multicellular organism requires coordinated changes in diverse cell types. These cellular changes generate organs of the correct size, shape, and functionality. In plants, the growth hormone auxin induces stem elongation in response to shade; however, which cell types of the stem perceive the auxin signal and contribute to organ growth is poorly understood. Here, we blocked the transcriptional response to auxin within specific tissues to show that auxin signaling is required in many cell types for correct hypocotyl growth in shade, with a key role for the epidermis. Combining genetic manipulations in Arabidopsis thaliana with transcriptional profiling of the hypocotyl epidermis from Brassica rapa, we show that auxin acts in the epidermis in part by inducing activity of the locally acting, growth-promoting brassinosteroid pathway. Our findings clarify cell-specific auxin function in the hypocotyl and highlight the complexity of cell type interactions within a growing organ. PMID:27401556

  13. Shade Trading: An Emerging Riparian Forest-Based Payment for Ecosystem Services Market in Oregon, USA.

    PubMed

    Guillozet, Kathleen

    2015-10-01

    This paper describes the regulatory and compliance context for Oregon's emerging ecosystem services (ES) market in riparian shade to meet water quality obligations. In Oregon's market as with many other ES programs, contracts and other regulatory documents not only delimit the obligations and liabilities of different parties, but also constitute a primary mechanism through which ES service delivery is measured. Through a review of compliance criteria I find that under Oregon's shade trades, permittees are held to a number of input-based criteria, which essentially affirm that parties comply with predetermined practices and procedures, and one 'pseudo output based' criterion, in which ES delivery is estimated through a model. The case presented in the paper critically engages with the challenges of measuring ES and in assessing the outcomes of ES projects. It places these challenges as interrelated and proposes that market designers, policymakers, and other stakeholders should consider explicit efficacy, efficiency, and equity targets.

  14. Determining individual tree shade length: A guide for silviculturists. Forest Service general technical report

    SciTech Connect

    Geier-Hayes, K.; Hayes, M.A.; Basford, D.D.

    1995-09-01

    Shade may be critical through the summer for conifer regeneration survival on warm, dry sites. This guide provides to silviculturists a method for determining tree shadow lengths in a straight line from the tree`s base to the shadow tip from southern Utah to northern Idaho for May 10 through October 11 on different slopes, aspects, and for two tree shapes. Tables and graphs provide shade lengths based on a tree length factor that describes shadow length as a function on tree height. Tree length factors for solar noon and 2 hours before and after solar noon are provided for cylinder-shaped trees. Tree length factors for solar noon are provided for cone-shaped trees. Information about shadow angles and shadow sweep rates are also provided.

  15. Metabolomic analysis of the effect of shade treatment on the nutritional and sensory qualities of green tea.

    PubMed

    Lee, Lan-Sook; Choi, Ji Hea; Son, Nari; Kim, Sang-Hee; Park, Jong-Dae; Jang, Dae-Ja; Jeong, Yoonhwa; Kim, Hyun-Jin

    2013-01-16

    We analyzed metabolites from a 50% aqueous methanol extract of green teas treated with different shade periods (0, 15, 18, and 20 days) to investigate the effect of low light on their nutritional and sensory qualities. The shaded groups could be clearly distinguished from the control (0 day), and the 20 day group was separated from the 15 and 18 day groups. The shade treatment increased quercetin-galactosylrutinoside, kaempferol-glucosylrutinoside, epicatechin gallate, epigallocatechin gallate, tryptophan, phenylalanine, theanine, glutamine, glutamate, and caffeine levels but decreased quercetin-glucosylrutinoside, kaempferol-glucoside, gallocatechin, and epigallocatechin levels. Further studies on the nutritional benefits of these metabolites are needed. However, this result, along with the sensory evaluation and color measurement data, suggests that shade treatment improves the nutritional and sensory quality of green tea. Thus, we proposed a metabolomic pathway related to the effect of low light, which could elucidate the relationship between low light and tea quality.

  16. Auxin transport through PIN-FORMED 3 (PIN3) controls shade avoidance and fitness during competition.

    PubMed

    Keuskamp, Diederik H; Pollmann, Stephan; Voesenek, Laurentius A C J; Peeters, Anton J M; Pierik, Ronald

    2010-12-28

    Plants grow in dense vegetations at the risk of being out-competed by neighbors. To increase their competitive power, plants display adaptive responses, such as rapid shoot elongation (shade avoidance) to consolidate light capture. These responses are induced upon detection of proximate neighbors through perception of the reduced ratio between red (R) and far-red (FR) light that is typical for dense vegetations. The plant hormone auxin is a central regulator of plant development and plasticity, but until now it has been unknown how auxin transport is controlled to regulate shade-avoidance responses. Here, we show that low R:FR detection changes the cellular location of the PIN-FORMED 3 (PIN3) protein, a regulator of auxin efflux, in Arabidopsis seedlings. As a result, auxin levels in the elongating hypocotyls are increased under low R:FR. Seedlings of the pin3-3 mutant lack this low R:FR-induced increase of endogenous auxin in the hypocotyl and, accordingly, have no elongation response to low R:FR. We hypothesize that low R:FR-induced stimulation of auxin biosynthesis drives the regulation of PIN3, thus allowing shade avoidance to occur. The adaptive significance of PIN3-mediated control of shade-avoidance is shown in plant competition studies. It was found that pin3 mutants are outcompeted by wild-type neighbors who suppress fitness of pin3-3 by 40%. We conclude that low R:FR modulates the auxin distribution by a change in the cellular location of PIN3, and that this control can be of great importance for plants growing in dense vegetations.

  17. Sun/shade conditions affect recruitment and local adaptation of a columnar cactus in dry forests

    PubMed Central

    Miranda-Jácome, Antonio; Montaña, Carlos; Fornoni, Juan

    2013-01-01

    Background and Aims Facilitation among plants in water-limited environments (i.e. where evapotranspiration overcomes the availability of water during the growing season) has been considered a local adaptation to water and light conditions. Among cacti, early life-history stages can benefit from the facilitative effects of nurse plants that reduce solar radiation and water stress. However, whether light condition itself acts as an agent of selection through facilitation remains untested. The aim of this study was to determine (1) whether light conditions affect seedling recruitment, (2) whether the positive effect of shade on seedling recruitment is more intense under more stressful conditions and (3) whether shade condition (facilitation) reduces the magnitude of local adaptation on seedling recruitment relative to full sunlight conditions. Methods A reciprocal transplant experiment, coupled with the artificial manipulation of sun/shade conditions, was performed to test for the effects of local adaptation on germination, seedling survival and growth, using two demes of the columnar cactus Pilosocereus leucocephalus, representing different intensities of stressful conditions. Key Results Full sunlight conditions reduced recruitment success and supported the expectation of lower recruitment in more stressful environments. Significant local adaptation was mainly detected under full sunlight conditions, indicating that this environmental factor acts as an agent of selection at both sites. Conclusions The results supported the expectation that the magnitude of local adaptation, driven by the effects of facilitative nurse plants, is less intense under reduced stressful conditions. This study is the first to demonstrate that sun/shade conditions act as a selective agent accounting for local adaptation in water-limited environments, and that facilitation provided by nurse plants in these environments can attenuate the patterns of local adaptation among plants benefiting

  18. Black wildebeest seek shade less and use solar orientation behavior more than do blue wildebeest.

    PubMed

    Lease, Hilary M; Murray, Ian W; Fuller, Andrea; Hetem, Robyn S

    2014-10-01

    Many ungulates, including wildebeest, seek shade and orient their bodies relative to incoming solar radiation in order to reduce environmental heat loads. Blue (Connochaetes taurinus) and black wildebeest (Connochaetes gnou), which co-exist artificially in some reserves in South Africa, are thought to adopt different thermoregulatory behaviors to mitigate high environmental heat loads. However, whether or not blue and black wildebeest use different behaviors to reduce heat loads in regions where they co-occur has never previously been examined. We compared the shade seeking and solar orientation behavior of free-ranging blue and black wildebeest in summer at three locations in South Africa where both species co-occur. We found that blue wildebeest exhibited more shade seeking behavior than did black wildebeest at all times of day, at all study sites. Black wildebeest remained in the sun but were more likely than blue wildebeest to orient their bodies parallel to the sun at all study sites, a behavior which reduces the amount of surface area exposed to incoming radiation. Black wildebeest were most likely to employ parallel solar orientation during the hottest times of the day when the sun was not directly overhead (i.e., solar noon ± 1 hour). We thus demonstrate that co-occurring blue and black wildebeest use different thermoregulatory behaviors to reduce high heat loads. It is possible that the lack of shade in the historical distribution of black wildebeest led to selective pressure for reliance on solar orientation. Differences in thermoregulatory behavior can affect species-specific heat loads, habitat use, body mass, fitness and grazing activity. Such differences may also allow blue and black wildebeest to inhabit separate microclimates within the same habitat, provided there is sufficient heterogeneity in vegetation structure, potentially facilitating reproductive isolation. PMID:25436964

  19. Mapping the spectral variability in photosynthetic and non-photosynthetic vegetation, soils, and shade using AVIRIS

    NASA Technical Reports Server (NTRS)

    Roberts, Dar A.; Smith, Milton O.; Sabol, Donald E.; Adams, John B.; Ustin, Susan L.

    1992-01-01

    The primary objective of this research was to map as many spectrally distinct types of green vegetation (GV), non-photosynthetic vegetation (NPV), shade, and soil (endmembers) in an Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) scene as is warranted by the spectral variability of the data. Once determined, a secondary objective was to interpret these endmembers and their abundances spatially and spectrally in an ecological context.

  20. Black wildebeest seek shade less and use solar orientation behavior more than do blue wildebeest.

    PubMed

    Lease, Hilary M; Murray, Ian W; Fuller, Andrea; Hetem, Robyn S

    2014-10-01

    Many ungulates, including wildebeest, seek shade and orient their bodies relative to incoming solar radiation in order to reduce environmental heat loads. Blue (Connochaetes taurinus) and black wildebeest (Connochaetes gnou), which co-exist artificially in some reserves in South Africa, are thought to adopt different thermoregulatory behaviors to mitigate high environmental heat loads. However, whether or not blue and black wildebeest use different behaviors to reduce heat loads in regions where they co-occur has never previously been examined. We compared the shade seeking and solar orientation behavior of free-ranging blue and black wildebeest in summer at three locations in South Africa where both species co-occur. We found that blue wildebeest exhibited more shade seeking behavior than did black wildebeest at all times of day, at all study sites. Black wildebeest remained in the sun but were more likely than blue wildebeest to orient their bodies parallel to the sun at all study sites, a behavior which reduces the amount of surface area exposed to incoming radiation. Black wildebeest were most likely to employ parallel solar orientation during the hottest times of the day when the sun was not directly overhead (i.e., solar noon ± 1 hour). We thus demonstrate that co-occurring blue and black wildebeest use different thermoregulatory behaviors to reduce high heat loads. It is possible that the lack of shade in the historical distribution of black wildebeest led to selective pressure for reliance on solar orientation. Differences in thermoregulatory behavior can affect species-specific heat loads, habitat use, body mass, fitness and grazing activity. Such differences may also allow blue and black wildebeest to inhabit separate microclimates within the same habitat, provided there is sufficient heterogeneity in vegetation structure, potentially facilitating reproductive isolation.

  1. Surface layer response to topographic solar shading in Antarctica's dry valleys

    NASA Astrophysics Data System (ADS)

    Katurji, Marwan; Zawar-Reza, Peyman; Zhong, Shiyuan

    2013-11-01

    The effects of topographic shading on local flow transitioning and atmospheric surface layer properties are investigated using observational data from the Miers Valley, one of the dry valleys of Antarctica. A unique data set was collected during a 9 day period in the summer of 2012 using an eddy covariance system and a sound detection and ranging that provided vertical profiles of wind and turbulence characteristics in the surface layer and the lower part of the boundary layer within the Miers Valley. This data set is ideal for investigating the dynamics of flow transitioning due to topographic shading, without the atmosphere experiencing complete darkness. The lack of atmospheric humidity, soil moisture, and surface vegetation in the dry valleys creates an atmosphere within which the microclimatic responses are amplified, and as a result, the valley atmosphere is extremely sensitive to solar radiation. The entire measured valley boundary layer (up to 250 m above ground level) feels the transition from an unstable to a stable stratification as the surface temperature drops by 10°C in response to the topographic shading. Wavelet analysis reveals the dynamics of flow deceleration, stagnation, and oscillations as the flow transitions from an unstable to a stable boundary layer. The larger air mass (along valley) scales to the longer terrain fetch, and as the shade is cast over the valley, it retains some of the longer wavelengths of the flow. The cross-valley component influenced by the slopes is quicker to adjust to short-period oscillations and takes around three more hours before it couples with the oscillatory pattern of the along-valley flow.

  2. Simulation of tree shade impacts on residential energy use for space conditioning in Sacramento

    NASA Astrophysics Data System (ADS)

    Simpson, J. R.; McPherson, E. G.

    Tree shade reduces summer air conditioning demand and increases winter heating load by intercepting solar energy that would otherwise heat the shaded structure. We evaluate the magnitude of these effects here for 254 residential properties participating in a utility sponsored tree planting program in Sacramento, California. Tree and building characteristics and typical weather data are used to model hourly shading and energy used for space conditioning for each building for a period of one year. There were an average of 3.1 program trees per property which reduced annual and peak (8 h average from 1 to 9 p.m. Pacific Daylight Time) cooling energy use 153 kWh (7.1%) and 0.08 kW (2.3%) per tree, respectively. Annual heating load increased 0.85 GJ (0.80 MBtu, 1.9%) per tree. Changes in cooling load were smaller, but percentage changes larger, for newer buildings. Averaged over all homes, annual cooling savings of 15.25 per tree were reduced by a heating penalty of 5.25 per tree, for net savings of 10.00 per tree from shade. We estimate an annual cooling penalty of 2.80 per tree and heating savings of 6.80 per tree from reduced wind speed, for a net savings of 4.00 per tree, and total annual savings of 14.00 per tree (43.00 per property). Results are found to be consistent with previous simulations and the limited measurements available.

  3. Leaf morphological and physiological adjustments to the spectrally selective shade imposed by anthocyanins in Prunus cerasifera.

    PubMed

    Kyparissis, A; Grammatikopoulos, G; Manetas, Y

    2007-06-01

    Prunus domestica L. has green leaves, whereas Prunus cerasifera Ehrh. var. atropurpurea has red leaves due to the presence of mesophyll anthocyanins. We compared morphological and photosynthetic characteristics of leaves of these species, which were sampled from shoots grafted in pairs on P. domestica rootstocks, each pair comprising one shoot of each species. Two hypotheses were tested: (1) anthocyanins protect red leaves against photoinhibition; and (2) red leaves display shade characteristics because of light attenuation by anthocyanins. Parameters were measured seasonally, during a period of increasing water stress, which caused a similar drop in shoot water potential in each species. As judged by predawn measurements of maximum PSII yield, chronic photoinhibition did not develop in either species and, despite the anthocyanic screen, the red leaves of P. cerasifera displayed lower light-adapted PSII yields and higher non-photochemical quenching than the green leaves of P. domestica. Thus, it appears that, in this system, anthocyanins afford little photoprotection. As predicted by the shade acclimation hypothesis, red leaves were thinner and had a lower stomatal frequency, area- based CO2 assimilation rate, apparent carboxylation efficiency and chlorophyll a:b ratio than green leaves. However, red leaves were similar to green leaves in conductivity to water vapor diffusion, dry-mass-based chlorophyll concentrations and carotenoid:chlorophyll ratios. The data for red leaves indicate adaptations to a green-depleted, red-enriched shade, rather than a neutral or canopy-like shade. Thus, green light attenuation by anthocyanins may impose a limitation on leaf thickness. Moreover, the selective depletion of light at wavelengths that are preferentially absorbed by PSII and chlorophyll b may lead to adjustments in chlorophyll pigment ratios to compensate for the uneven spectral distribution of internal light. The apparent photosynthetic cost associated with lost photons

  4. Self-shading in cork oak seedlings: Functional implications in heterogeneous light environments

    NASA Astrophysics Data System (ADS)

    Esteso-Martínez, Jordán; Peguero-Pina, José Javier; Valladares, Fernando; Morales, Fermín; Gil-Pelegrín, Eustaquio

    2010-07-01

    The high self-shading found in Quercus suber seedlings has been interpreted as a feature common for plants growing in high light environments. But many studies reveal that Q. suber has high survival rates under low-light conditions, so a high degree of self-shading could be the consequence of a foliage composed of many small leaves, with no drawbacks for coping with low light. A characterization of the light environment in a Q. suber stand together with a study of photosynthetic parameters of full sunlight-exposed (FSLE) and self-shaded (SS) leaves were carried out to tackle this apparent contradiction. Although the number of sunflecks longer than 120 min during the 3 months of measurements was low, the occurrence of at least one sunfleck longer than 120 min per day in the understory of the forest studied was very common. Sunflecks shorter than 30 min promoted an increase in net photosynthesis ( A) in FSLE leaves, but not in SS leaves. However, sunflecks longer than 60 min led to a very strong decrease in A and in actual photosystem II efficiency (Φ PSII) in FSLE leaves, when compared to sunflecks shorter than 30 min. In SS leaves, changes were, again, negligible. The multi-layered foliage of Q. suber seedlings allowed i) FSLE leaves to obtain the maximum photosynthetic yield for short sunflecks, and ii) SS leaves to increase their contribution to the photosynthesis of the whole plant for long sunflecks, thus, optimizing the use of light by FSLE and SS leaves during short and long sunflecks respectively. Therefore, shoot architecture of Q. suber seedlings involving high levels of self-shading allows to adequately cope with the low but highly heterogeneous light conditions of the understory, particularly when sunflecks of contrasting durations take place as it is frequently the case for evergreen Mediterranean forests.

  5. Experimental investigation on the characteristics of a solar cell under different illumination intensities and shading areas

    NASA Astrophysics Data System (ADS)

    Xiao, W. B.; Hu, F. Y.; He, X. D.; Zhang, H. M.; Wu, H. M.

    2015-06-01

    The characteristics of a solar cell, the short-circuit current ( I sc ), the open-circuit voltage ( V oc ), the maximum power point ( V m , I m ), the fill factor ( FF) and the photoelectric conversion efficiency ( η) under different illumination intensities and shading areas have been experimentally investigated. The work factor ω is given by ω = (1 - A/ A 0) × S/ S 0, where A 0 is the total solar cell area, A the shading area, S 0 the benchmark reference irradiation level, and S the new level of the irradiation, is introduced to take the light intensity and shading area into account. The results show that Isc and Im increase on an approximately linear increasing way with ω, but V oc and V m approach the saturation levels. The reason is that the current is a linear function of ω, and the relationship of the voltage to ω is logarithmic. We also found I sc ( V m ) to depend more on ω than I m ( V oc ). In addition, we observed that η tended to increase linearly with ω, but FF tended to converge to saturation. The reason for the behavior of η is the reduction in the contact resistance and in the electron-hole recombination with increasing ω. However, FF is mainly determined by V oc . The improvement in the solar cell performance with increasing ω results from an increase in the current, but not in the voltage or the fill factor.

  6. Comparative study on growth performance of two shade trees in tea agroforestry system.

    PubMed

    Kalita, Rinku Moni; Das, Ashesh Kumar; Nath, Arun Jyoti

    2014-07-01

    An attempt was made to study the stem growth of two native dominant shade tree species in terms of annual girth increment in three dominant girth size categories for two years in tea agroforestry system of Barak Valley, Assam. Fifty two sampling plots of 0.1 ha size were established and all trees exceeding 10 cm girth over bark at breast height (1.37 m) were uniquely identified, tagged, and annually measured for girth increment, using metal tape during December 2010-12. Albizia lebbeck and A. odoratissima were dominant shade tree species registering 82% of appearance of the individuals studied. The girth class was categorized into six different categories where 30-50 cm, 50-70 cm and 70-90 cm were dominating girth classes and selected for increment study. Mean annual girth increment ranged from 1.41 cm in Albizia odoratissima (50-70 cm girth class) to 2.97 cm in Albizia lebbeck (70-90 cm girth class) for the first year and 1.70 cm in Albizia odoratissima (50-70 cm girth class) to 3.09 cm in Albizia lebbeck (70-90 cm girth class) for the second year. Albizia lebbeck exhibited better growth in all prominent girth classes as compared to Albizia odoratissima during the observation period. The two shade tree species showed similar trend of growth in both the years of observation and significant difference in girth increment.

  7. The extraction of 3D shape from texture and shading in the human brain.

    PubMed

    Georgieva, Svetlana S; Todd, James T; Peeters, Ronald; Orban, Guy A

    2008-10-01

    We used functional magnetic resonance imaging to investigate the human cortical areas involved in processing 3-dimensional (3D) shape from texture (SfT) and shading. The stimuli included monocular images of randomly shaped 3D surfaces and a wide variety of 2-dimensional (2D) controls. The results of both passive and active experiments reveal that the extraction of 3D SfT involves the bilateral caudal inferior temporal gyrus (caudal ITG), lateral occipital sulcus (LOS) and several bilateral sites along the intraparietal sulcus. These areas are largely consistent with those involved in the processing of 3D shape from motion and stereo. The experiments also demonstrate, however, that the analysis of 3D shape from shading is primarily restricted to the caudal ITG areas. Additional results from psychophysical experiments reveal that this difference in neuronal substrate cannot be explained by a difference in strength between the 2 cues. These results underscore the importance of the posterior part of the lateral occipital complex for the extraction of visual 3D shape information from all depth cues, and they suggest strongly that the importance of shading is diminished relative to other cues for the analysis of 3D shape in parietal regions.

  8. The extraction of depth structure from shading and texture in the macaque brain.

    PubMed

    Nelissen, Koen; Joly, Olivier; Durand, Jean-Baptiste; Todd, James T; Vanduffel, Wim; Orban, Guy A

    2009-01-01

    We used contrast-agent enhanced functional magnetic resonance imaging (fMRI) in the alert monkey to map the cortical regions involved in the extraction of 3D shape from the monocular static cues, texture and shading. As in the parallel human imaging study, we contrasted the 3D condition to several 2D control conditions. The extraction of 3D shape from texture (3D SfT) involves both ventral and parietal regions, in addition to early visual areas. Strongest activation was observed in CIP, with decreasing strength towards the anterior part of the intraparietal sulcus (IPS). In the ventral stream 3D SfT sensitivity was observed in a ventral portion of TEO. The extraction of 3D shape from shading (3D SfS) involved predominantly ventral regions, such as V4 and a dorsal potion of TEO. These results are similar to those obtained earlier in human subjects and indicate that the extraction of 3D shape from texture is performed in both ventral and dorsal regions for both species, as are the motion and disparity cues, whereas shading is mainly processed in the ventral stream.

  9. Response of an algal assemblage to nutrient enrichment and shading in a Hawaiian stream

    USGS Publications Warehouse

    Stephens, S.H.; Brasher, A.M.D.; Smith, C.M.

    2012-01-01

    To investigate the effects of nitrate enrichment, phosphate enrichment, and light availability on benthic algae, nutrient-diffusing clay flowerpots were colonized with algae at two sites in a Hawaiian stream during spring and autumn 2002 using a randomized factorial design. The algal assemblage that developed under the experimental conditions was investigated by determining biomass (ash-free dry mass and chlorophyll a concentrations) and composition of the diatom assemblage. In situ pulse amplitude-modulated fluorometry was also used to model photosynthetic rate of the algal assemblage. Algal biomass and maximum photosynthetic rate were significantly higher at the unshaded site than at the shaded site. These parameters were higher at the unshaded site with either nitrate, or to a lesser degree, nitrate plus phosphate enrichment. Analysis of similarity of diatom assemblages showed significant differences between shaded and unshaded sites, as well as between spring and autumn experiments, but not between nutrient treatments. However, several individual species of diatoms responded significantly to nitrate enrichment. These results demonstrate that light availability (shaded vs. unshaded) is the primary limiting factor to algal growth in this stream, with nitrogen as a secondary limiting factor. ?? 2011 Springer Science+Business Media B.V.

  10. Influence of translucence/opacity and shade in the flexural strength of lithium disilicate ceramics

    PubMed Central

    Santos, Mila Oliveira; do Amaral, Flávia Lucisano Botelho; França, Fabiana Mantovani Gomes; Basting, Roberta Tarkany

    2015-01-01

    Background: Lithium disilicate ceramic system consists of glass ceramic ingots with different grades of translucence which may influence its flexural strength. Aims: To assess the three-point flexural strength of the different lithium disilicate-based ceramic ingots (IPS e.max Press/Ivoclar Vivadent) with different levels of translucence and shade. Materials and Methods: Six groups of ceramic ingots were selected to represent different levels of translucence and shade (HTA1, HTBL2, LTA2, LTB2, MO2, and HO). They measured 25 mm × 5 mm × 2 mm (n = 10), according to ISO 6872 specifications, and tested on a universal test machine (EMIC). Statistical Analysis Used: A one-way analysis of variance (ANOVA) was used (α = 0.05). Results: The results (in MPa) were: HTA1 = 392.98; HTBL2 = 390.74; LTA2 = 390.46; LTB2 = 389.92; MO2 = 390.43; HO = 391.96. ANOVA showed no significant difference among groups (P = 0.1528). Conclusions: Different levels of translucence, opacity and shade of ingots did not affect their mechanical strength, and the use of these ceramics should be guided by the esthetic demands of each clinical situation. PMID:26430304

  11. Object-Based Analysis of LIDAR Geometric Features for Vegetation Detection in Shaded Areas

    NASA Astrophysics Data System (ADS)

    Lin, Yu-Ching; Lin, ChinSu; Tsai, Ming-Da; Lin, Chun-Lin

    2016-06-01

    The extraction of land cover information from remote sensing data is a complex process. Spectral information has been widely utilized in classifying remote sensing images. However, shadows limit the use of multispectral images because they result in loss of spectral radiometric information. In addition, true reflectance may be underestimated in shaded areas. In land cover classification, shaded areas are often left unclassified or simply assigned as a shadow class. Vegetation indices from remote sensing measurement are radiation-based measurements computed through spectral combination. They indicate vegetation properties and play an important role in remote sensing of forests. Airborne light detection and ranging (LiDAR) technology is an active remote sensing technique that produces a true orthophoto at a single wavelength. This study investigated three types of geometric lidar features where NDVI values fail to represent meaningful forest information. The three features include echo width, normalized eigenvalue, and standard deviation of the unit weight observation of the plane adjustment, and they can be derived from waveform data and discrete point clouds. Various feature combinations were carried out to evaluate the compensation of the three lidar features to vegetation detection in shaded areas. Echo width was found to outperform the other two features. Furthermore, surface characteristics estimated by echo width were similar to that by normalized eigenvalues. Compared to the combination of only NDVI and mean height difference, those including one of the three features had a positive effect on the detection of vegetation class.

  12. Occlusion processing and smooth surface shading for fully computed synthetic holography

    NASA Astrophysics Data System (ADS)

    Underkoffler, John S.

    1997-04-01

    Computation for synthetic holography typically takes one of two forms: the `stereogram' approach, in which a large number of 2D perspective views are rendered and assembled into a composite fringe pattern; and the `fully computed' approach, in which the physics of light propagation from geometric surfaces and the resulting interference patterns at a recording plane are all simulated. Algorithms implementing the stereogram approach often generate their component perspective views by taking advantage of dedicated graphics hardware, capable of rapid rendering with hidden- surface removal and smooth shading. However, these standard computer graphics schemes for occlusion and shading are inappropriate for fully computed hologram synthesis. We describe an efficient algorithm that starts with a standard- form geometric description of the desired scene and generates a list of simple holographic `primitives' that can be transformed into the final interference pattern by a simple fringe rendering program. The algorithm simultaneously performs the multiple-viewpoint equivalent of hidden surface removal, so that nearer surfaces and objects properly occlude those more distant, and surface shading, so that each object appears solid and exhibits the correct visual behavior in response to lighting in the scene.

  13. Light intensity modulates the regulatory network of the shade avoidance response in Arabidopsis

    PubMed Central

    Hersch, Micha; Lorrain, Séverine; de Wit, Mieke; Trevisan, Martine; Ljung, Karin; Bergmann, Sven; Fankhauser, Christian

    2014-01-01

    Plants such as Arabidopsis thaliana respond to foliar shade and neighbors who may become competitors for light resources by elongation growth to secure access to unfiltered sunlight. Challenges faced during this shade avoidance response (SAR) are different under a light-absorbing canopy and during neighbor detection where light remains abundant. In both situations, elongation growth depends on auxin and transcription factors of the phytochrome interacting factor (PIF) class. Using a computational modeling approach to study the SAR regulatory network, we identify and experimentally validate a previously unidentified role for long hypocotyl in far red 1, a negative regulator of the PIFs. Moreover, we find that during neighbor detection, growth is promoted primarily by the production of auxin. In contrast, in true shade, the system operates with less auxin but with an increased sensitivity to the hormonal signal. Our data suggest that this latter signal is less robust, which may reflect a cost-to-robustness tradeoff, a system trait long recognized by engineers and forming the basis of information theory. PMID:24733935

  14. Light intensity modulates the regulatory network of the shade avoidance response in Arabidopsis.

    PubMed

    Hersch, Micha; Lorrain, Séverine; de Wit, Mieke; Trevisan, Martine; Ljung, Karin; Bergmann, Sven; Fankhauser, Christian

    2014-04-29

    Plants such as Arabidopsis thaliana respond to foliar shade and neighbors who may become competitors for light resources by elongation growth to secure access to unfiltered sunlight. Challenges faced during this shade avoidance response (SAR) are different under a light-absorbing canopy and during neighbor detection where light remains abundant. In both situations, elongation growth depends on auxin and transcription factors of the phytochrome interacting factor (PIF) class. Using a computational modeling approach to study the SAR regulatory network, we identify and experimentally validate a previously unidentified role for long hypocotyl in far red 1, a negative regulator of the PIFs. Moreover, we find that during neighbor detection, growth is promoted primarily by the production of auxin. In contrast, in true shade, the system operates with less auxin but with an increased sensitivity to the hormonal signal. Our data suggest that this latter signal is less robust, which may reflect a cost-to-robustness tradeoff, a system trait long recognized by engineers and forming the basis of information theory.

  15. Comparison of the translucency of shaded zirconia all-ceramic systems

    PubMed Central

    Ulusoy, Mutahhar

    2014-01-01

    PURPOSE The purpose of this study was to evaluate and compare the translucency of shaded zirconia all-ceramic systems. MATERIALS AND METHODS Translucency of 3 different zirconia all-ceramic systems colored by different techniques was compared with a lithium disilicate glass-ceramic (IPS e.max Press). Square-shaped specimens with 0.5 mm thickness were fabricated from In-Ceram YZ, ICE Zirkon and Katana systems in A1, A2 and A3.5 shades according to Vitapan Classical shade tab (n=11). Specimens were then veneered and glazed with corresponding veneer ceramic recommended by each zirconia system manufacturer and the total thickness was set to 1.5 mm. Translucency measurements were performed with VITA Easyshade Compact spectrophotometer after each stage and translucency parameter was calculated. Data were statistically analyzed with repeated measures ANOVA and Tukey multiple comparison test. RESULTS The control group was significantly more translucent than the zirconia systems (P<.05). ICE Zirkon cores showed the least translucency; neither In-Ceram YZ nor Katana systems were superior to each other in terms of translucency. Translucency of all specimens was decreased after veneering, and the translucency rankings were changed. CONCLUSION Coloring technique did not have a significant effect on translucency of zirconia cores. Although zirconia systems were less translucent than lithium disilicate glass ceramic, they had partial translucency and there were translucency differences among the zirconia systems. Chroma affected the translucency of precolored zirconia cores. PMID:25352964

  16. Shade-grown coffee in Puerto Rico: Opportunities to preserve biodiversity while reinvigorating a struggling agricultural commodity

    USGS Publications Warehouse

    Borkhataria, R.; Collazo, J.A.; Groom, M.J.; Jordan-Garcia, A.

    2012-01-01

    Shade-grown coffee contributes to biodiversity conservation and has many ecological benefits. We reviewed historical trends in coffee production and interviewed 100 coffee growers in 1999 to determine current management practices and attitudes toward the cultivation of sun and shade coffee in Puerto Rico. We discuss the outlook for the coffee industry in the 21st century and implications for biodiversity conservation, hoping lessons from Puerto Rico will apply to the international coffee industry. Throughout the 20th century, government intervention, including subsidies and technical assistance, supported coffee farming in Puerto Rico. In an effort to modernize coffee production and increase yields, the conversion from shade to sun coffee plantations was encouraged. Despite government support, the amount of land devoted to this once dominant agricultural commodity declined markedly between 1982 and 2007 (84%), due to labor shortages, low income, and catastrophic hurricanes. We found that a return to shaded plantations would be embraced by most farmers. Growers of shaded coffee were generally happier with their cultivation practices (89.3% satisfied) than growers of sun coffee (60.9% satisfied), valued biodiversity, and were willing to cultivate coffee under shade if given similar incentives to those received for farming sun coffee. The future of the coffee industry in Puerto Rico may depend on government programs that capitalize upon emerging markets for sustainably produced, shade-grown coffee. We conclude that where governments have close ties to the coffee industry, they should strive to wed economic development with the conservation of biodiversity and associated ecological services by providing support and incentives for the production of shade coffee. ?? 2011 Elsevier B.V.

  17. 16S rRNA assessment of the influence of shading on early-successional biofilms in experimental streams

    PubMed Central

    Lehmann, Katja; Singer, Andrew; Bowes, Michael J.; Ings, Nicola L.; Field, Dawn; Bell, Thomas

    2015-01-01

    Elevated nutrient levels can lead to excessive biofilm growth, but reducing nutrient pollution is often challenging. There is therefore interest in developing control measures for biofilm growth in nutrient-rich rivers that could act as complement to direct reductions in nutrient load. Shading of rivers is one option that can mitigate blooms, but few studies have experimentally examined the differences in biofilm communities grown under shaded and unshaded conditions. We investigated the assembly and diversity of biofilm communities using in situ mesocosms within the River Thames (UK). Biofilm composition was surveyed by 454 sequencing of 16S amplicons (∼400 bp length covering regions V6/V7). The results confirm the importance of sunlight for biofilm community assembly; a resource that was utilized by a relatively small number of dominant taxa, leading to significantly less diversity than in shaded communities. These differences between unshaded and shaded treatments were either because of differences in resource utilization or loss of diatom-structures as habitats for bacteria. We observed more co-occurrence patterns and network interactions in the shaded communities. This lends further support to the proposal that increased river shading can help mitigate the effects from macronutrient pollution in rivers. PMID:26499485

  18. Hydraulics and life history of tropical dry forest tree species: coordination of species' drought and shade tolerance.

    PubMed

    Markesteijn, Lars; Poorter, Lourens; Bongers, Frans; Paz, Horacio; Sack, Lawren

    2011-07-01

    Plant hydraulic architecture has been studied extensively, yet we know little about how hydraulic properties relate to species' life history strategies, such as drought and shade tolerance. The prevailing theories seem contradictory. We measured the sapwood (K(s) ) and leaf (K(l) ) hydraulic conductivities of 40 coexisting tree species in a Bolivian dry forest, and examined associations with functional stem and leaf traits and indices of species' drought (dry-season leaf water potential) and shade (juvenile crown exposure) tolerance. Hydraulic properties varied across species and between life-history groups (pioneers vs shade-tolerant, and deciduous vs evergreen species). In addition to the expected negative correlation of K(l) with drought tolerance, we found a strong, negative correlation between K(l) and species' shade tolerance. Across species, K(s) and K(l) were negatively correlated with wood density and positively with maximum vessel length. Consequently, drought and shade tolerance scaled similarly with hydraulic properties, wood density and leaf dry matter content. We found that deciduous species also had traits conferring efficient water transport relative to evergreen species. Hydraulic properties varied across species, corresponding to the classical trade-off between hydraulic efficiency and safety, which for these dry forest trees resulted in coordinated drought and shade tolerance across species rather than the frequently hypothesized trade-off.

  19. 16S rRNA assessment of the influence of shading on early-successional biofilms in experimental streams.

    PubMed

    Lehmann, Katja; Singer, Andrew; Bowes, Michael J; Ings, Nicola L; Field, Dawn; Bell, Thomas

    2015-12-01

    Elevated nutrient levels can lead to excessive biofilm growth, but reducing nutrient pollution is often challenging. There is therefore interest in developing control measures for biofilm growth in nutrient-rich rivers that could act as complement to direct reductions in nutrient load. Shading of rivers is one option that can mitigate blooms, but few studies have experimentally examined the differences in biofilm communities grown under shaded and unshaded conditions. We investigated the assembly and diversity of biofilm communities using in situ mesocosms within the River Thames (UK). Biofilm composition was surveyed by 454 sequencing of 16S amplicons (∼400 bp length covering regions V6/V7). The results confirm the importance of sunlight for biofilm community assembly; a resource that was utilized by a relatively small number of dominant taxa, leading to significantly less diversity than in shaded communities. These differences between unshaded and shaded treatments were either because of differences in resource utilization or loss of diatom-structures as habitats for bacteria. We observed more co-occurrence patterns and network interactions in the shaded communities. This lends further support to the proposal that increased river shading can help mitigate the effects from macronutrient pollution in rivers. PMID:26499485

  20. Mycorrhizal responses in wheat: shading decreases growth but does not lower the contribution of the fungal phosphate uptake pathway.

    PubMed

    Stonor, Rebecca N; Smith, Sally E; Manjarrez, Maria; Facelli, Evelina; Smith, F Andrew

    2014-08-01

    Effects have been investigated of reduced C supply (induced by shade) on arbuscular mycorrhizal (AM) colonisation, mycorrhizal growth responses (MGRs) and on AM-mediated and direct uptake of phosphate (Pi) (using (32)P) in wheat, a plant that does not usually respond positively to AM colonisation. Shading markedly reduced growth and shoot/root dry weight ratios of both AM and non-mycorrhizal wheat, indicating decreased photosynthetic C supply. However, shading had very little effect on percent root length colonised by Rhizophagus irregularis or Gigaspora margarita or on MGRs, which remained slightly positive or zero, regardless of shade; there were no growth depressions under shade. By 6 weeks, when the contributions of the AM pathway were measured with (32)P supplied in small hyphal compartments, R. irregularis had supplied 23 to 28% of shoot P with no significant effect of shading. Data show that reduced C availability did not reduce the contribution of the AM pathway to plant P, so the fungi were not acting physiologically as parasites. These results support our previous hypothesis that lack of positive MGR is not necessarily the outcome of excessive C use by the fungi or failure to deliver P via the AM pathway.

  1. 16S rRNA assessment of the influence of shading on early-successional biofilms in experimental streams.

    PubMed

    Lehmann, Katja; Singer, Andrew; Bowes, Michael J; Ings, Nicola L; Field, Dawn; Bell, Thomas

    2015-12-01

    Elevated nutrient levels can lead to excessive biofilm growth, but reducing nutrient pollution is often challenging. There is therefore interest in developing control measures for biofilm growth in nutrient-rich rivers that could act as complement to direct reductions in nutrient load. Shading of rivers is one option that can mitigate blooms, but few studies have experimentally examined the differences in biofilm communities grown under shaded and unshaded conditions. We investigated the assembly and diversity of biofilm communities using in situ mesocosms within the River Thames (UK). Biofilm composition was surveyed by 454 sequencing of 16S amplicons (∼400 bp length covering regions V6/V7). The results confirm the importance of sunlight for biofilm community assembly; a resource that was utilized by a relatively small number of dominant taxa, leading to significantly less diversity than in shaded communities. These differences between unshaded and shaded treatments were either because of differences in resource utilization or loss of diatom-structures as habitats for bacteria. We observed more co-occurrence patterns and network interactions in the shaded communities. This lends further support to the proposal that increased river shading can help mitigate the effects from macronutrient pollution in rivers.

  2. The contribution of dynamic changes in photosynthesis to shade tolerance of two conifer species.

    PubMed

    Ma, Ziyu; Behling, Shawn; Ford, E David

    2014-07-01

    Generally 'shade tolerance' refers to the capacity of a plant to exist at low light levels but characteristics of shade can vary and must be taken into account in defining the term. We studied Abies amabilis Dougl. ex J.Forbes and Tsuga heterophylla (Raf.) Sarg. under a forest canopy in the northwest of the Olympic Peninsula, USA, which has low annual sunshine hours and frequent overcast days. Using BF3 sunshine sensors, we surveyed diffuse and total light received by saplings growing under a range of canopy openness up to 30%. We measured variation in photosynthetic capacity over the growing season and within days and estimated photosynthesis induction in relation to ambient light. Three components of shade tolerance are associated with variation in light climate: (i) Total light on the floor of an 88-year stand of naturally regenerated T. heterophylla was greater on overcast than clear days. Light on overcast days varied throughout the day sometimes with a cyclical pattern. (ii) Photosynthetic capacity, Amax, varied both through the growing season and within days. Amax was generally greater in the latter part of the growing season, being limited by temperature and stomatal conductance, gs, at times during the early part. Saplings in more shaded areas had lower Amax and in the latter part of the growing season Amax was found to decline from mid-afternoon. (iii) Two patterns of photosynthesis induction to increased light were found. In a mean ambient light of 139 μmol m(-2) s(-1), induction had a curvilinear response to a step increase in light with a mean time constant, τ, of 112.3 s. In a mean ambient light of 74 μmol m(-2) s(-1), induction had a two-part increase: one with τ1 of 11.3 s and the other with τ2 of 184.0 s. These are the smallest published values of τ to date. (iv) Both variation in photosynthetic capacity and induction are components of shade tolerance where light varies over time. Amax acclimates to seasonal and diurnal

  3. Effect of summer conditions and shade on the production and metabolism of Holstein dairy cows on pasture in temperate climate.

    PubMed

    Van Laer, E; Tuyttens, F A M; Ampe, B; Sonck, B; Moons, C P H; Vandaele, L

    2015-09-01

    For dairy cattle on pasture in temperate regions, it is largely unknown to what degree hot summer conditions impact energy metabolism, milk yield and milk composition and how effective shade is in reducing these negative effects. During the summer of 2012, a herd of Holstein cows was kept on pasture without access to shade (treatment NS). During the summers of 2011 and 2013, the herd was divided into a group with (treatment S) and a group without (treatment NS) access to shade. Shade was provided by young trees combined with shade cloths (80% reduction in solar radiation). A weather station registered the local climatic conditions on open pasture, from which we calculated daily average Heat Load Index (HLI) values. The effects of HLI and shade on rectal temperature (RT), blood plasma indicators of hyperventilation and metabolic changes due to heat stress, milk yield and milk composition were investigated. RT increased with increasing HLI, but was less for S cows than for NS cows (by 0.02°C and 0.03°C increase per unit increase of HLI, respectively). Hyperchloraemia (an increased blood plasma concentration of Cl-), a sign of hyperventilation, increased for NS cows but not for S cows. The plasma concentration of alkaline phosphatase, a regulator of energy metabolism in the liver, decreased with increasing HLI for NS cows only. Access to shade, thus, reduced the effect of HLI on RT, hyperchloraemia and the regulation of metabolism by the liver. As HLI increased, the plasma concentration of cholesterol decreased (indicating increased lipolysis) and the plasma concentration of creatinine increased (indicating increased protein catabolism). These effects did not differ between S and NS cows. For NS cows, after a lag-time of 2 days, the milk yield decreased with increasing HLI. For S cows, the milk yield was unaffected by HLI and its quadratic factor. The milk concentrations of lactose, protein and fat decreased as HLI increased, but only the effect on milk protein

  4. Effect of summer conditions and shade on the production and metabolism of Holstein dairy cows on pasture in temperate climate.

    PubMed

    Van Laer, E; Tuyttens, F A M; Ampe, B; Sonck, B; Moons, C P H; Vandaele, L

    2015-09-01

    For dairy cattle on pasture in temperate regions, it is largely unknown to what degree hot summer conditions impact energy metabolism, milk yield and milk composition and how effective shade is in reducing these negative effects. During the summer of 2012, a herd of Holstein cows was kept on pasture without access to shade (treatment NS). During the summers of 2011 and 2013, the herd was divided into a group with (treatment S) and a group without (treatment NS) access to shade. Shade was provided by young trees combined with shade cloths (80% reduction in solar radiation). A weather station registered the local climatic conditions on open pasture, from which we calculated daily average Heat Load Index (HLI) values. The effects of HLI and shade on rectal temperature (RT), blood plasma indicators of hyperventilation and metabolic changes due to heat stress, milk yield and milk composition were investigated. RT increased with increasing HLI, but was less for S cows than for NS cows (by 0.02°C and 0.03°C increase per unit increase of HLI, respectively). Hyperchloraemia (an increased blood plasma concentration of Cl-), a sign of hyperventilation, increased for NS cows but not for S cows. The plasma concentration of alkaline phosphatase, a regulator of energy metabolism in the liver, decreased with increasing HLI for NS cows only. Access to shade, thus, reduced the effect of HLI on RT, hyperchloraemia and the regulation of metabolism by the liver. As HLI increased, the plasma concentration of cholesterol decreased (indicating increased lipolysis) and the plasma concentration of creatinine increased (indicating increased protein catabolism). These effects did not differ between S and NS cows. For NS cows, after a lag-time of 2 days, the milk yield decreased with increasing HLI. For S cows, the milk yield was unaffected by HLI and its quadratic factor. The milk concentrations of lactose, protein and fat decreased as HLI increased, but only the effect on milk protein

  5. Fruit load and canopy shading affect leaf characteristics and net gas exchange of 'Spring' navel orange trees.

    PubMed

    Syvertsen, J P; Goñi, C; Otero, A

    2003-09-01

    Five-year-old 'Spring' navel (Citrus sinensis (L.) Osbeck) orange trees were completely defruited, 50% defruited or left fully laden to study effects of fruit load on concentrations of nitrogen (N) and carbohydrate, net assimilation of CO2 (Ac) and stomatal conductance (gs) of mature leaves on clear winter days just before fruit harvest. Leaves on defruited trees were larger, had higher starch concentrations and greater leaf dry mass per area (LDMa) than leaves on fruited trees. Both Ac and gs were more than 40% lower in sunlit leaves on defruited trees than in sunlit leaves on trees with fruit. Leaves immediately adjacent to fruit were smaller, had lower leaf nitrogen and carbohydrate concentrations, lower LDMa and lower Ac than leaves on non-fruiting branches of the same trees. Removing half the crop increased individual fruit mass, but reduced fruit color development. Half the trees were shaded with 50% shade cloth for 4 months before harvest to determine the effects of lower leaf temperature (Tl) and leaf-to-air vapor pressure difference on leaf responses. On relatively warm days when sunlit Tl > 25 degrees C, shade increased Ac and gs, but had no effect on the ratio of internal to ambient CO2 (Ci/Ca) concentration in leaves, implying that high mesophyll temperatures in sunlit leaves were more important than gs in limiting Ac. Sunlit leaves were more photoinhibited than shaded leaves on cooler days when Tl < 25 degrees C. Shade decreased total soluble sugar concentrations in leaves, but had no effect on leaf starch concentrations. Shading had no effects on canopy volume, yield or fruit size, but shaded fruit developed better external color than sun-exposed fruit. Overall, the presence of a normal fruit crop resulted in lower foliar carbohydrate concentrations and higher Ac compared with defruited trees, except on warm days when Ac was reduced by high leaf temperatures.

  6. In response to partial plant shading, the lack of phytochrome A does not directly induce leaf senescence but alters the fine-tuning of chlorophyll biosynthesis.

    PubMed

    Brouwer, Bastiaan; Gardeström, Per; Keech, Olivier

    2014-07-01

    Phytochrome is thought to control the induction of leaf senescence directly, however, the signalling and molecular mechanisms remain unclear. In the present study, an ecophysiological approach was used to establish a functional connection between phytochrome signalling and the physiological processes underlying the induction of leaf senescence in response to shade. With shade it is important to distinguish between complete and partial shading, during which either the whole or only a part of the plant is shaded, respectively. It is first shown here that, while PHYB is required to maintain chlorophyll content in a completely shaded plant, only PHYA is involved in maintaining the leaf chlorophyll content in response to partial plant shading. Second, it is shown that leaf yellowing associated with strong partial shading in phyA-mutant plants actually correlates to a decreased biosynthesis of chlorophyll rather than to an increase of its degradation. Third, it is shown that the physiological impact of this decreased biosynthesis of chlorophyll in strongly shaded phyA-mutant leaves is accompanied by a decreased capacity to adjust the Light Compensation Point. However, the increased leaf yellowing in phyA-mutant plants is not accompanied by an increase of senescence-specific molecular markers, which argues against a direct role of PHYA in inducing leaf senescence in response to partial shade. In conclusion, it is proposed that PHYA, but not PHYB, is essential for fine-tuning the chlorophyll biosynthetic pathway in response to partial shading. In turn, this mechanism allows the shaded leaf to adjust its photosynthetic machinery to very low irradiances, thus maintaining a positive carbon balance and repressing the induction of leaf senescence, which can occur under prolonged periods of shade.

  7. Growth, allometry and shade tolerance of understory saplings of four subalpine conifers in central Japan.

    PubMed

    Takahashi, Koichi; Obata, Yoshiko

    2014-03-01

    The conifers Abies veitchii, A. mariesii, Picea jezoensis var. hondoensis, Tsuga diversifolia dominate in subalpine forests in central Japan. We expected that species differences in shade tolerance and in aboveground and belowground architecture are important for their coexistence. We examined net production and carbon allocation of understory saplings. Although the four species allocated similar amounts of biomass to roots at a given trunk height, the root-zone area of T. diversifolia was greater than that of the three other species. T. diversifolia often dominates shallow soil sites, such as ridge and rocky slopes, and, therefore, a wide spread of lateral roots would be an adaptation to such edaphic conditions. Crown width and leaf and branch mass were greatest for T. diversifolia and A. mariesii, followed in order by A. veitchii and P. jezoensis var. hondoensis. Although leaf mass of P. jezoensis var. hondoensis was lowest among the four species, species differences were not found in the net production per sapling because net production per leaf mass was greatest for P. jezoensis var. hondoensis. The leaf lifespan was longer in the order A. mariesii, T. diversifolia, P. jezoensis var. hondoensis and A. veitchii. The minimum rate of net production per leaf mass required to maintain the current sapling leaf mass (MRNP(LM)) was lowest in A. mariesii and T. diversifolia, and increased in the order of A. veitchii and P. jezoensis var. hondoensis. A. mariesii and T. diversifolia may survive in shade conditions by a lower MRNP(LM) than the two other species. Therefore, species differences in aboveground and belowground architecture and MRNPLM reflected their shade tolerance and regeneration strategies, which contribute to their coexistence.

  8. Seed limitation restricts population growth in shaded populations of a perennial woodland orchid.

    PubMed

    Jacquemyn, Hans; Brys, Rein; Jongejans, Eelke

    2010-01-01

    Seed production and seedling recruitment are thought to be of minor importance in determining population dynamics and long-term viability in long-lived perennial plants. Seed addition experiments, on the other hand, have amply shown that supplemental addition of seeds almost always, irrespective of longevity, results in increased seedling recruitment. Any change in the environment that affects fruit and seed production can thus be expected to affect seedling recruitment, but the extent to which increased fruit and seed production affect overall population dynamics remains relatively unknown. In this paper, we present demographic data of six populations of the long-lived woodland orchid Orchis purpurea that were monitored for seven consecutive years (2002-2008) occurring in two contrasting light environments. We use a nested life table response experiment (LTRE) at the vital rate level to disentangle the relative contributions of each of six annual transitions, six sites, and two light environments on the population dynamics of this species and to determine vital rate variations that contributed most to variation in population growth rate. Population growth rates (lamda) were significantly higher in the light environment than in the shaded environment (average lamda = 0.9930 and 1.0492 in the shaded and light environment, respectively). The LTRE analysis showed that variation in fecundity and, to a lesser extent, variation in growth made the largest total contributions to variation in lamda, whereas the contributions of variation in survival were almost negligible. Fruit production was two times larger and the net reproductive rate (R0) was approximately six times higher in the light environment than in shaded areas, suggesting that variables related to reproduction are the key drivers of population dynamics of this long-lived orchid species in different light environments. Our results indicate that light is an important factor affecting population dynamics of

  9. Implications of mountain shading on calculating energy for snowmelt using unstructured triangular meshes

    NASA Astrophysics Data System (ADS)

    Marsh, C.; Pomeroy, J. W.; Spiteri, R.

    2012-12-01

    In many parts of the world, the snowmelt energy balance is dominated by net solar shortwave radiation. This is the case in the Canadian Rocky Mountains, where clear skies dominate the winter and spring. In mountainous regions, irradiance at the snow surface is not only affected by solar angles, atmospheric transmittance, and the slope and aspect of immediate topography, but also by horizon-shadows, i.e., shadows from surrounding terrain. Many hydrological models do not consider such horizon-shadows and the accumulation of errors in estimating solar irradiance by neglecting horizon-shadows may lead to significant errors in calculating the timing and rate of snowmelt due to the seasonal storage of internal energy in the snowpack. An unstructured triangular-mesh-based horizon-shading model is compared to standard self-shading algorithms in the Marmot Creek Research Basin (MCRB), Alberta, Canada. A systematic basin-wide over-prediction (basin mean expressed as phase change mass (assumed constant albedo of 0.8): 14 mm, maximum: 200 mm) in net shortwave radiation is observed when only self-shading is considered. The horizon-shadow model is run at a point scale at three sites throughout the MCRB to investigate the effects of topographic scale on the model results. In addition, the model results are compared to measurements of mountain shadows via orthorectified timelapse digital photographs and measured surface irradiance. The horizon-model irradiance data are used to drive a point-scale energy balance model, SNOBAL, via The Cold Regions Hydrological Model, an HRU-based hydrologic model. Melt timing is shown to differ by up to four days by neglecting horizon-shadows. It is further hypothesized that the errors might be much larger in basins with more rugged topography. Finally, a consideration of the intersection of unstructured-mesh and HRU landscape representations is discussed.

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

    PubMed Central

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

    2015-01-01

    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. PMID:25859337

  11. Hydrocarbon emissions from twelve urban shade trees of the Los Angeles, California, Air Basin

    NASA Astrophysics Data System (ADS)

    Corchnoy, Stephanie B.; Arey, Janet; Atkinson, Roger

    The large-scale planting of shade trees in urban areas to counteract heat-island effects and to minimize energy use is currently being discussed. Among the costs to be considered in a cost/benefit analysis of such a program is the potential for additional reactive organic compounds in the atmosphere due to emissions from these trees. In this program, 15 species of potential shade trees for the Los Angeles Air Basin were studied and emission rates were determined for 11 of these trees, with one further tree (Crape myrtle) exhibiting no detectable emissions. The emission rates normalized to dry leaf weight and corrected to 30°C were (in μg g -1 h -1), ranked from lowest to highest emission rate: Crape myrtle, none detected; Camphor, 0.03; Aleppo pine, 0.15; Deodar cedar, 0.29; Italian Stone pine, 0.42; Monterey pine, 0.90; Brazilian pepper, 1.3; Canary Island pine, 1.7; Ginkgo, 3.0; California pepper, 3.7; Liquidambar, 37; Carrotwood, 49. In addition to the emission rates per unit biomass, the biomass per tree must be factored into any assessment of the relative merits of the various trees, since some trees have higher biomass constants than others. The present data shows that there are large differences in emission rates among different tree species and this should be factored into decision-making as to which shade trees to plant. Based solely on the presently determined emission rates, the Crape myrtle and Camphor tree are good choices for large-scale planting, while the Carrotwood tree and Liquidambar are poor choices due to their high isoprene emission rates.

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

    PubMed

    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. PMID:22466529

  13. Shade trees reduce building energy use and CO2 emissions from power plants

    SciTech Connect

    Akbari, H.

    2001-11-01

    Urban shade trees offer significant benefits in reducing building air-conditioning demand and improving urban air quality by reducing smog. The savings associated with these benefits vary by climate region and can be up to $200 per tree. The cost of planting trees and maintaining them can vary from $10 to $500 per tree. Tree-planting programs can be designed to have lower costs so that they offer potential savings to communities that plant trees. Our calculations suggest that urban trees play a major role in sequestering C02 and thereby delay global warming. We estimate that a tree planted in Los Angeles avoids the combustion of 18 kg of carbon annually, even though it sequesters only 4.5-11 kg (as it would if growing in a forest). In this sense, one shade tree in Los Angeles is equivalent to three to five forest trees. In a recent analysis for Baton Rouge, Sacramento, and Salt Lake City, we estimated that planting an average of four shade trees per house (each with a top view cross section of 50 m2) would lead to an annual reduction in carbon emissions from power plants of 16,000, 41,000, and 9000 t, respectively (the per-tree reduction in carbon emissions is about 10-11 kg per year). These reductions only account for the direct reduction in the net cooling- and heating-energy use of buildings. Once the impact of the community cooling is included, these savings are increased by at least 25 percent.

  14. Light acclimation optimizes leaf functional traits despite height-related constraints in a canopy shading experiment.

    PubMed

    Coble, Adam P; Cavaleri, Molly A

    2015-04-01

    Within-canopy gradients of leaf functional traits have been linked to both light availability and vertical gradients in leaf water potential. While observational studies can reveal patterns in leaf traits, within-canopy experimental manipulations can provide mechanistic insight to tease apart multiple interacting drivers. Our objectives were to disentangle effects of height and light environment on leaf functional traits by experimentally shading branches along vertical gradients within a sugar maple (Acer saccharum) forest. Shading reduced leaf mass per area (LMA), leaf density, area-based leaf nitrogen (N(area)), and carbon:nitrogen (C:N) ratio, and increased mass-based leaf nitrogen (N(mass)), highlighting the importance of light availability on leaf morphology and chemistry. Early in the growing season, midday leaf water potential (Ψ(mid)), LMA, and N(area) were driven primarily by height; later in the growing season, light became the most important driver for LMA and Narea. Carbon isotope composition (δ(13)C) displayed strong, linear correlations with height throughout the growing season, but did not change with shading, implying that height is more influential than light on water use efficiency and stomatal behavior. LMA, leaf density, N(mass), C:N ratio, and δ(13)C all changed seasonally, suggesting that leaf ageing effects on leaf functional traits are equally as important as microclimatic conditions. Overall, our results indicate that: (1) stomatal sensitivity to vapor pressure deficit or Ψ(mid) constrains the supply of CO2 to leaves at higher heights, independent of light environment, and (2) LMA and N(area) distributions become functionally optimized through morphological acclimation to light with increasing leaf age despite height-related constraints.

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

    PubMed

    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.

  16. Shade trees reduce building energy use and CO2 emissions from power plants.

    PubMed

    Akbari, H

    2002-01-01

    Urban shade trees offer significant benefits in reducing building air-conditioning demand and improving urban air quality by reducing smog. The savings associated with these benefits vary by climate region and can be up to $200 per tree. The cost of planting trees and maintaining them can vary from $10 to $500 per tree. Tree-planting programs can be designed to have lower costs so that they offer potential savings to communities that plant trees. Our calculations suggest that urban trees play a major role in sequestering CO2 and thereby delay global warming. We estimate that a tree planted in Los Angeles avoids the combustion of 18 kg of carbon annually, even though it sequesters only 4.5-11 kg (as it would if growing in a forest). In this sense, one shade tree in Los Angeles is equivalent to three to five forest trees. In a recent analysis for Baton Rouge, Sacramento, and Salt Lake City, we estimated that planting an average of four shade trees per house (each with a top view cross section of 50 m2) would lead to an annual reduction in carbon emissions from power plants of 16,000, 41,000, and 9000 t, respectively (the per-tree reduction in carbon emissions is about 10-11 kg per year). These reductions only account for the direct reduction in the net cooling- and heating-energy use of buildings. Once the impact of the community cooling is included, these savings are increased by at least 25%. PMID:11833899

  17. Light acclimation optimizes leaf functional traits despite height-related constraints in a canopy shading experiment.

    PubMed

    Coble, Adam P; Cavaleri, Molly A

    2015-04-01

    Within-canopy gradients of leaf functional traits have been linked to both light availability and vertical gradients in leaf water potential. While observational studies can reveal patterns in leaf traits, within-canopy experimental manipulations can provide mechanistic insight to tease apart multiple interacting drivers. Our objectives were to disentangle effects of height and light environment on leaf functional traits by experimentally shading branches along vertical gradients within a sugar maple (Acer saccharum) forest. Shading reduced leaf mass per area (LMA), leaf density, area-based leaf nitrogen (N(area)), and carbon:nitrogen (C:N) ratio, and increased mass-based leaf nitrogen (N(mass)), highlighting the importance of light availability on leaf morphology and chemistry. Early in the growing season, midday leaf water potential (Ψ(mid)), LMA, and N(area) were driven primarily by height; later in the growing season, light became the most important driver for LMA and Narea. Carbon isotope composition (δ(13)C) displayed strong, linear correlations with height throughout the growing season, but did not change with shading, implying that height is more influential than light on water use efficiency and stomatal behavior. LMA, leaf density, N(mass), C:N ratio, and δ(13)C all changed seasonally, suggesting that leaf ageing effects on leaf functional traits are equally as important as microclimatic conditions. Overall, our results indicate that: (1) stomatal sensitivity to vapor pressure deficit or Ψ(mid) constrains the supply of CO2 to leaves at higher heights, independent of light environment, and (2) LMA and N(area) distributions become functionally optimized through morphological acclimation to light with increasing leaf age despite height-related constraints. PMID:25596955

  18. The integration of disparity, shading and motion parallax cues for depth perception in humans and monkeys.

    PubMed

    Schiller, Peter H; Slocum, Warren M; Jao, Brian; Weiner, Veronica S

    2011-03-01

    A visual stimulus display was created that enabled us to examine how effectively the three depth cues of disparity, motion parallax and shading can be integrated in humans and monkeys. The display was designed to allow us to present these three depth cues separately and in various combinations. Depth was processed most effectively and most rapidly when all three cues were presented together indicating that these separate cues are integrated at yet unknown sites in the brain. Testing in humans and monkeys yielded similar results suggesting that monkeys are a good animal model for the study of the underlying neural mechanisms of depth perception.

  19. Proper restorative material selection, digital processes allow highly esthetic shade match combined with layered porcelain.

    PubMed

    Kahng, Luke S

    2014-03-01

    Today's digital technologies are affording dentists and laboratory technicians more control over material choices for creating restorations and fabricating dental prostheses. Digital processes can potentially enable technicians to create ideal marginal areas and account for the thickness and support of layering porcelain over substructures in the design process. In this case report of a restoration of a single central incisor, a number of issues are addressed that are central to using the newest digital technology. As demonstrated, shade selection is a crucial early step in any restorative case preparation.

  20. Determination of the Annual Shading Potential of Salix Purpurea Coppice using Hemispherical Photographs

    NASA Astrophysics Data System (ADS)

    Holzapfel, G.; Weihs, P.; Stockreiter, L.; Hoffmann, E.

    2012-04-01

    The European Water Framework Directive (WFD) aims to achieve a good ecological potential and good surface water chemical status for all surface waters. Widely constant shading with riparian vegetation is the potential natural plant cover condition and plays a key role by the implementation of the WFD. The shading effect of vegetation is considered to be particularly relevant for small and medium sized rivers with slow flow velocity. Soil Bioengineering measures effect technical (e.g. soil protection), ecological and socio-economical issues on river systems. Positive ecological effects are based on the development of the used plants and result among others in shading of the water body. Natural bank vegetation provides very important niches for terrestrial and aquatic stages and reduces the incident solar radiation up to 95%. Consequently large riparian wooded areas form a microclimate that leads to a decrease of water temperature or prevent an increase. They even reduce evaporation and increase the relative air humidity which contributes to reducing water temperature and enlarges the oxygen uptake capacity. Accordingly the daily variations of temperature and those of oxygen content are definitely lower in vegetated areas. This issue is especially important considering climate change scenarios with increasing water temperatures. From an ecological point of view it is essential to quantify the processes. There are different ways to characterize densities of vegetation. Most of them - such as the method by Braun-Blanquet and Londo - rely on estimations of the dominance of species. Applying this kind of procedures on riparian vegetation result in uncertainties due to the strong variations in height and densities. Hemispherical photographs are a standardized method in forest ecology under more or less uniform forest stand conditions. However it is now hardly used for riparian vegetation stands. Questions that will be addressed are the determination of annual stand

  1. Thermal and Electrical Effects of Partial Shade in Monolithic Thin-Film Photovoltaic Modules: Preprint

    SciTech Connect

    Silverman, Timothy J.; Deceglie, Michael G.; Sun, Xingshu; Garris, Rebekah L.; Alam, Muhammad Ashraful; Deline, Chris; Kurtz, Sarah

    2015-09-02

    Photovoltaic cells can be damaged by reverse bias stress, which arises during service when a monolithically integrated thin-film module is partially shaded. We introduce a model for describing a module's internal thermal and electrical state, which cannot normally be measured. Using this model and experimental measurements, we present several results with relevance for reliability testing and module engineering: Modules with a small breakdown voltage experience less stress than those with a large breakdown voltage, with some exceptions for modules having light-enhanced reverse breakdown. Masks leaving a small part of the masked cells illuminated can lead to very high temperature and current density compared to masks covering entire cells.

  2. Degradation of fipronil (Termidor) in aqueous solution stored in polyethylene tanks exposed to sunlight or shade.

    PubMed

    Husen, T J; Spomer, N A; Kamble, S T

    2009-05-01

    Pest Management Professionals commonly use polyethylene or fiberglass tanks for mixing and applying termiticides. We investigated the stability of fipronil (Termidor SC) (0.06%, 0.09% and 0.125% active ingredient) in aqueous solutions stored in polyethylene tanks under sun and shade for 2 week. Chemical analysis of tank-mixed solutions sampled at 0, 24, 48, 72, 168 and 336 h indicated that fipronil remained stable. Our data indicated that polyethylene tanks prevent fipronil from photodegradation and these tanks can be safely used for short term storage (up to 2 week) of liquid termiticides.

  3. Thermal and Electrical Effects of Partial Shade in Monolithic Thin-Film Photovoltaic Modules

    SciTech Connect

    Silverman, Timothy J.; Deceglie, Michael G.; Sun, Xingshu; Garris, Rebekah L.; Alam, Muhammad Ashraful; Deline, Chris; Kurtz, Sarah

    2015-06-14

    Photovoltaic cells can be damaged by reverse bias stress, which arises during service when a monolithically integrated thin-film module is partially shaded. We introduce a model for describing a module's internal thermal and electrical state, which cannot normally be measured. Using this model and experimental measurements, we present several results with relevance for reliability testing and module engineering: Modules with a small breakdown voltage experience less stress than those with a large breakdown voltage, with some exceptions for modules having light-enhanced reverse breakdown. Masks leaving a small part of the masked cells illuminated can lead to very high temperature and current density compared to masks covering entire cells.

  4. An individual-based forest model links canopy dynamics and shade tolerances along a soil moisture gradient

    PubMed Central

    Liénard, Jean; Strigul, Nikolay

    2016-01-01

    Understanding how forested ecosystems respond to climatic changes is a challenging problem as forest self-organization occurs simultaneously across multiple scales. Here, we explore the hypothesis that soil water availability shapes above-ground competition and gap dynamics, and ultimately alters the dominance of shade tolerant and intolerant species along the moisture gradient. We adapt a spatially explicit individual-based model with simultaneous crown and root competitions. Simulations show that the transition from xeric to mesic soils is accompanied by an increase in shade-tolerant species similar to the patterns documented in the North American forests. This transition is accompanied by a change from water to sunlight competitions, and happens at three successive stages: (i) mostly water-limited parkland, (ii) simultaneously water- and sunlight-limited closed canopy forests featuring a very sparse understory, and (iii) mostly sunlight-limited forests with a populated understory. This pattern is caused by contrasting successional dynamics that favour either shade-tolerant or shade-intolerant species, depending on soil moisture and understory density. This work demonstrates that forest patterns along environmental gradients can emerge from spatial competition without physiological trade-offs between shade and growth tolerance. Mechanistic understanding of population processes involved in the forest–parkland–desert transition will improve our ability to explain species distributions and predict forest responses to climatic changes. PMID:26998329

  5. Photosynthetic traits of Siebold's beech seedlings in changing light conditions by removal of shading trees under elevated CO₂.

    PubMed

    Watanabe, M; Kitaoka, S; Eguchi, N; Watanabe, Y; Satomura, T; Takagi, K; Satoh, F; Koike, T

    2016-01-01

    The purpose of this study was to obtain basic information on acclimation capacity of photosynthesis in Siebold's beech seedlings to increasing light intensity under future elevated CO2 conditions. We monitored leaf photosynthetic traits of these seedlings in changing light conditions (before removal of shade trees, the year after removal of shade trees and after acclimation to open conditions) in a 10-year free air CO2 enrichment experiment in northern Japan. Elevated CO2 did not affect photosynthetic traits such as leaf mass per area, nitrogen content and biochemical photosynthetic capacity of chloroplasts (i.e. maximum rate of carboxylation and maximum rate of electron transport) before removal of the shade trees and after acclimation to open conditions; in fact, a higher net photosynthetic rate was maintained under elevated CO2 . However, in the year after removal of the shade trees, there was no increase in photosynthesis rate under elevated CO2 conditions. This was not due to photoinhibition. In ambient CO2 conditions, leaf mass per area and nitrogen content were higher in the year after removal of shade trees than before, whereas there was no increase under elevated CO2 conditions. These results indicate that elevated CO2 delays the acclimation of photosynthetic traits of Siebold's beech seedlings to increasing light intensity.

  6. An individual-based forest model links canopy dynamics and shade tolerances along a soil moisture gradient.

    PubMed

    Liénard, Jean; Strigul, Nikolay

    2016-02-01

    Understanding how forested ecosystems respond to climatic changes is a challenging problem as forest self-organization occurs simultaneously across multiple scales. Here, we explore the hypothesis that soil water availability shapes above-ground competition and gap dynamics, and ultimately alters the dominance of shade tolerant and intolerant species along the moisture gradient. We adapt a spatially explicit individual-based model with simultaneous crown and root competitions. Simulations show that the transition from xeric to mesic soils is accompanied by an increase in shade-tolerant species similar to the patterns documented in the North American forests. This transition is accompanied by a change from water to sunlight competitions, and happens at three successive stages: (i) mostly water-limited parkland, (ii) simultaneously water- and sunlight-limited closed canopy forests featuring a very sparse understory, and (iii) mostly sunlight-limited forests with a populated understory. This pattern is caused by contrasting successional dynamics that favour either shade-tolerant or shade-intolerant species, depending on soil moisture and understory density. This work demonstrates that forest patterns along environmental gradients can emerge from spatial competition without physiological trade-offs between shade and growth tolerance. Mechanistic understanding of population processes involved in the forest-parkland-desert transition will improve our ability to explain species distributions and predict forest responses to climatic changes. PMID:26998329

  7. Growth effects of shading and sedimentation in two tropical seagrass species: Implications for port management and impact assessment.

    PubMed

    Benham, Claudia F; Beavis, Sara G; Hendry, Rebecca A; Jackson, Emma L

    2016-08-15

    Seagrass meadows in many parts of the globe are threatened by a range of processes including port development, dredging and land clearing in coastal catchments, which can reduce water clarity and increase sedimentation pressure. As rates of seagrass loss increase, there is an urgent need to understand the potential impacts of development on these critical species. This research compares the effects of shading and burial by fine sand on two seagrass species Zostera muelleri and Halophila ovalis in Port Curtis Bay, an industrial harbour located on the continental margin adjacent to the Great Barrier Reef Heritage Area, Australia. The research finds that shading in combination with burial causes a significant decline in growth rates in both species, but that burial ≥10mm reduces growth rates to a greater extent than shading. The paper concludes by discussing the implications of these findings for port management and impact assessment. PMID:27269385

  8. Light-scattering properties of a woven shade-screen material used for daylighting and solar heat-gain control

    SciTech Connect

    Jonsson, Jacob; Jonsson, Jacob C.; Lee, Eleanor S.; Rubin, Mike

    2008-08-01

    Shade-screens are widely used in commercial buildings as a way to limit the amount of direct sunlight that can disturb people in the building. The shade screens also reduce the solar heat-gain through glazing the system. Modern energy and daylighting analysis software such as EnergyPlus and Radiance require complete scattering properties of the scattering materials in the system. In this paper a shade screen used in the LBNL daylighting testbed is characterized using a photogoniometer and a normal angle of incidence integrating sphere. The data is used to create a complete bi-directional scattering distribution function (BSDF) that can be used in simulation programs. The resulting BSDF is compared to a model BADFs, both directly and by calculating the solar heat-gain coefficient for a dual pane system using Window 6.

  9. Effect of summer conditions and shade on behavioural indicators of thermal discomfort in Holstein dairy and Belgian Blue beef cattle on pasture.

    PubMed

    Van Laer, E; Moons, C P H; Ampe, B; Sonck, B; Vandaele, L; De Campeneere, S; Tuyttens, F A M

    2015-09-01

    Using behavioural indicators of thermal discomfort, that is, shade seeking, panting scores (PS) and respiration rate (RR), we evaluated the effect of hot summer conditions and shade, for a herd of adult Holstein dairy cows and a herd of Belgian Blue beef cows kept on pasture in a temperate area (Belgium). During the summer of 2012, both herds were kept on pasture without access to shade (NS). During the summers of 2011 and 2013 each herd was divided into one group with (S) and one without (NS) access to shade. Shade was provided by young trees with shade cloth (80% reduction in solar radiation) hung between them. For S cows, we investigated how shade use was related to hot conditions as quantified by six climatic indices. The heat load index (HLI), which incorporates air temperature and humidity, solar radiation and wind speed, was the best predictor of the six indices tested. In 2011, there was a relatively high threshold for use of shade. When HLI=90, shade use probability reached 17% for dairy cows and 27% for beef cows. In 2013, however, at HLI=90, shade use probability reached 48% for dairy cows and 41% for beef cows. For animals from the NS treatment we determined the effect of hot summer conditions on RR and PS (with 0=no panting and 4.5=extreme panting). In both types of cattle, an increase in black globe temperature was the best predictor for increasing RR and PS. Furthermore, we determined how the effect of hot summer conditions on RR and PS was affected by the use of shade. Under hot conditions (black globe temperature ⩾ 30°C), >50% of the animals under shade retained normal PS and RR (PS<1 and RR<90 breaths per minute), whereas normal RR and PS were significantly less prevalent for animals outside shade. Our findings suggest that, even in temperate summers, heat can induce thermal discomfort in cattle, as evidenced by increases in shade use, RR and PS, and that shade increases thermal comfort.

  10. Effect of summer conditions and shade on behavioural indicators of thermal discomfort in Holstein dairy and Belgian Blue beef cattle on pasture.

    PubMed

    Van Laer, E; Moons, C P H; Ampe, B; Sonck, B; Vandaele, L; De Campeneere, S; Tuyttens, F A M

    2015-09-01

    Using behavioural indicators of thermal discomfort, that is, shade seeking, panting scores (PS) and respiration rate (RR), we evaluated the effect of hot summer conditions and shade, for a herd of adult Holstein dairy cows and a herd of Belgian Blue beef cows kept on pasture in a temperate area (Belgium). During the summer of 2012, both herds were kept on pasture without access to shade (NS). During the summers of 2011 and 2013 each herd was divided into one group with (S) and one without (NS) access to shade. Shade was provided by young trees with shade cloth (80% reduction in solar radiation) hung between them. For S cows, we investigated how shade use was related to hot conditions as quantified by six climatic indices. The heat load index (HLI), which incorporates air temperature and humidity, solar radiation and wind speed, was the best predictor of the six indices tested. In 2011, there was a relatively high threshold for use of shade. When HLI=90, shade use probability reached 17% for dairy cows and 27% for beef cows. In 2013, however, at HLI=90, shade use probability reached 48% for dairy cows and 41% for beef cows. For animals from the NS treatment we determined the effect of hot summer conditions on RR and PS (with 0=no panting and 4.5=extreme panting). In both types of cattle, an increase in black globe temperature was the best predictor for increasing RR and PS. Furthermore, we determined how the effect of hot summer conditions on RR and PS was affected by the use of shade. Under hot conditions (black globe temperature ⩾ 30°C), >50% of the animals under shade retained normal PS and RR (PS<1 and RR<90 breaths per minute), whereas normal RR and PS were significantly less prevalent for animals outside shade. Our findings suggest that, even in temperate summers, heat can induce thermal discomfort in cattle, as evidenced by increases in shade use, RR and PS, and that shade increases thermal comfort. PMID:25994098

  11. Modified Shape from Shading Approach to SEM based Photoresist CD Metrology

    NASA Astrophysics Data System (ADS)

    Ahammad, Parvez; Mukherjee, Amar

    2002-12-01

    As the fabrication density increases in semiconductor manufacturing processes, cost effective determination of the exact dimensions of various device-interconnects becomes a critical issue. Single detector based critical dimension metrology systems are attractive due to cost effectiveness. Yet, deducing dimensions like sidewall curvature and 3D shape of the semiconductor surface are quite difficult using a single detector system. Non-destructive metrological systems are also very desirable in evaluating critical dimension and manufacturing error because they are inexpensive compared to multi-detector systems. In our paper, we build upon the physical modeling approach to modify a classical shape from shading algorithm to reconstruct the 3D shape from a single non-stereoscopic SEM image. Our ultimate aim is to design an efficient real-time, non-destructive CD-SEM system using a single detector. Appropriate reflectance function is utilized for low-excitation SEM imagery for reconstructing the depth map of the surface using the shape from shading algorithm. In this paper, we present the results from low-excitation SEM reflectance model used for SFS approach. We compare the results with a standard SFS algorithm that uses Lambertian reflectance model. We also discuss the advantages of this computer vision based approach compared to other destructive CD-SEM technologies.

  12. Performance of Integrated Systems of Automated Roller Shade Systems and Daylight Responsive Dimming Systems

    SciTech Connect

    Park, Byoung-Chul; Choi, An-Seop; Jeong, Jae-Weon; Lee, Eleanor S.

    2010-07-08

    Daylight responsive dimming systems have been used in few buildings to date because they require improvements to improve reliability. The key underlying factor contributing to poor performance is the variability of the ratio of the photosensor signal to daylight workplane illuminance in accordance with sun position, sky condition, and fenestration condition. Therefore, this paper describes the integrated systems between automated roller shade systems and daylight responsive dimming systems with an improved closed-loop proportional control algorithm, and the relative performance of the integrated systems and single systems. The concept of the improved closed-loop proportional control algorithm for the integrated systems is to predict the varying correlation of photosensor signal to daylight workplane illuminance according to roller shade height and sky conditions for improvement of the system accuracy. In this study, the performance of the integrated systems with two improved closed-loop proportional control algorithms was compared with that of the current (modified) closed-loop proportional control algorithm. In the results, the average maintenance percentage and the average discrepancies of the target illuminance, as well as the average time under 90percent of target illuminance for the integrated systems significantly improved in comparison with the current closed-loop proportional control algorithm for daylight responsive dimming systems as a single system.

  13. Population structure of Rudgea parquioides, a shade-tolerant shrub species, in Southern Brazil.

    PubMed

    Cardoso, Fernanda C G; Salvalaggio, Ana P B; Marques, Márcia C M

    2010-09-01

    The expectations that shade-tolerant forest species show 1) a population structure composed by a high amount of small individuals, and 2) biomass allocation for diameter higher than for height growth, were tested for Rudgea parquioides, a typical shrub in Southern Brazil. We described the size structure (height and stem diameter) and allometrical relations of a R. parquioides population by counting and measuring all the individuals in a 725m(2) area in the municipality of Curitiba (25°25'S; 49°19'W). A total of 916 individuals (12,634 ind.ha(-1)) were recorded in the area. The first expectation was supported, since distribution by height and diameter classes showed a predominance of small individuals (skewness coefficients > 1). On the other hand, the regression between height and stem base diameter showed slope β < 1, which indicates that growth in height is higher than in diameter, not supporting the second expectation. These results show that life strategies in shade-tolerant species may imply in more trade-off combinations than previously described.

  14. Analysis and Modeling of Parallel Photovoltaic Systems under Partial Shading Conditions

    NASA Astrophysics Data System (ADS)

    Buddala, Santhoshi Snigdha

    Since the industrial revolution, fossil fuels like petroleum, coal, oil, natural gas and other non-renewable energy sources have been used as the primary energy source. The consumption of fossil fuels releases various harmful gases into the atmosphere as byproducts which are hazardous in nature and they tend to deplete the protective layers and affect the overall environmental balance. Also the fossil fuels are bounded resources of energy and rapid depletion of these sources of energy, have prompted the need to investigate alternate sources of energy called renewable energy. One such promising source of renewable energy is the solar/photovoltaic energy. This work focuses on investigating a new solar array architecture with solar cells connected in parallel configuration. By retaining the structural simplicity of the parallel architecture, a theoretical small signal model of the solar cell is proposed and modeled to analyze the variations in the module parameters when subjected to partial shading conditions. Simulations were run in SPICE to validate the model implemented in Matlab. The voltage limitations of the proposed architecture are addressed by adopting a simple dc-dc boost converter and evaluating the performance of the architecture in terms of efficiencies by comparing it with the traditional architectures. SPICE simulations are used to compare the architectures and identify the best one in terms of power conversion efficiency under partial shading conditions.

  15. Metabolomics analysis reveals the compositional differences of shade grown tea (Camellia sinensis L.).

    PubMed

    Ku, Kang Mo; Choi, Jung Nam; Kim, Jiyoung; Kim, Jeong Kee; Yoo, Lang Gook; Lee, Sang Jun; Hong, Young-Shick; Lee, Choong Hwan

    2010-01-13

    The different cultivation methods affect tea quality by altering the basic metabolite profiles. In this study, the metabolome changes were investigated in green tea and shade cultured green tea (tencha) by liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-mass spectrometry (GC-MS) coupled with a multivariate data set. The principal component analysis (PCA) and orthogonal projection to latent structures discriminate analysis (OPLS-DA) of green tea clearly showed higher levels of galloylquinic acid, epigallocatechin, epicatechin, succinic acid, and fructose, together with lower levels of gallocatechin, strictinin, apigenin glucosyl arabinoside, quercetin p-coumaroylglucosyl-rhamnosylgalactoside, kaempferol p-coumaroylglucosylrhamnosylgalactoside, malic acid, and pyroglutamic acid than tencha. The effects of some seasonal variations were also observed in the primary metabolite concentrations such as amino acids and organic acids. In addition, green tea showed stronger antioxidant activity than tencha in both April and July. The antioxidant activity of green tea samples were significantly correlated with their total phenol and total flavonoid contents. This present study delineates the possibility to get high umami and less astringent green teas in shade culture. It highlights the metabolomic approaches to find out the effect of cultivation methods on chemical composition in plants and the relationship with antioxidant activity.

  16. Shading of colours in production of ceramic wares - reasons of formation

    NASA Astrophysics Data System (ADS)

    Partyka, J.; Lis, J.; Szwendke, P.; Wójczyk, M.

    2011-10-01

    One of the most important problems we have to deal with in the ceramic whiteware production is maintaining the stable tonality of colour of the glazes and the decoration of the ceramic products. This difficulties are especially significant for the large batches of production like for example the ceramic titles. The manufacturing of the one assortment for a few days requires the multiple preparation of the glazes and decorative materials. Similar problems occur during the renewing of the production of the given assortment after a longer period of time. The presented paper shows the results of the research covering this topics carried on in The Department of The Ceramic Technology on the AGH Krakow Poland. It is presented the kinds of the factors that can influence the formation of the shadings of coloured glazes: way of mixing of the glaze with stains, time of the mixing and the firing curves. The obtained results of the colour differences ΔE00, calculated from the "Cie L a b" measurements shows that the most important factor that influences the arising of the colour shading is the change of the firing condition and the sequence of the homogenization as the second important.

  17. Derivation of planetary topography using multi-image shape-from-shading

    USGS Publications Warehouse

    Lohse, V.; Heipke, C.; Kirk, R.L.

    2006-01-01

    In many cases, the derivation of high-resolution digital terrain models (DTMs) from planetary surfaces using conventional digital image matching is a problem. The matching methods need at least one stereo pair of images with sufficient texture. However, many space missions provide only a few stereo images and planetary surfaces often possess insufficient texture. This paper describes a method for the generation of high-resolution DTMs from planetary surfaces, which has the potential to overcome the described problem. The suggested method, developed by our group, is based on shape-from-shading using an arbitrary number of digital optical images, and is termed "multi-image shape-from-shading" (MI-SFS). The paper contains an explanation of the theory of MI-SFS, followed by a presentation of current results, which were obtained using images from NASA's lunar mission Clementine, and constitute the first practical application with our method using extraterrestrial imagery. The lunar surface is reconstructed under the assumption of different kinds of reflectance models (e.g. Lommel-Seeliger and Lambert). The represented results show that the derivation of a high-resolution DTM of real digital planetary images by means of MI-SFS is feasible. ?? 2006 Elsevier Ltd. All rights reserved.

  18. Stem transcriptome reveals mechanisms to reduce the energetic cost of shade-avoidance responses in tomato.

    PubMed

    Cagnola, Juan Ignacio; Ploschuk, Edmundo; Benech-Arnold, Tomás; Finlayson, Scott A; Casal, Jorge José

    2012-10-01

    While the most conspicuous response to low red/far-red ratios (R:FR) of shade light perceived by phytochrome is the promotion of stem growth, additional, less obvious effects may be discovered by studying changes in the stem transcriptome. Here, we report rapid and reversible stem transcriptome responses to R:FR in tomato (Solanum lycopersicum). As expected, low R:FR promoted the expression of growth-related genes, including those involved in the metabolism of cell wall carbohydrates and in auxin responses. In addition, genes involved in flavonoid synthesis, isoprenoid metabolism, and photosynthesis (dark reactions) were overrepresented in clusters showing reduced expression in the stem of low R:FR-treated plants. Consistent with these responses, low R:FR decreased the levels of flavonoids (anthocyanin, quercetin, kaempferol) and selected isoprenoid derivatives (chlorophyll, carotenoids) in the stem and severely reduced the photosynthetic capacity of this organ. However, lignin contents were unaffected. Low R:FR reduced the stem levels of jasmonate, which is a known inducer of flavonoid synthesis. The rate of stem respiration was also reduced in low R:FR-treated plants, indicating that by downsizing the stem photosynthetic apparatus and the levels of photoprotective pigments under low R:FR, tomato plants reduce the energetic cost of shade-avoidance responses.

  19. Initial characterization of shade avoidance response suggests functional diversity between Populus phytochrome B genes.

    SciTech Connect

    Karve, Abhijit A; Weston, David; Jawdy, Sara; Gunter, Lee E; Allen, Sara M; Yang, Xiaohan; Wullschleger, Stan D; Tuskan, Gerald A

    2012-01-01

    Shade avoidance signaling in higher plants involves perception of the incident red/far-red (R/FR) light by phytochromes and the modulation of downstream transcriptional networks to regulate developmental plasticity in relation to heterogeneous light environments. In this study, we characterized the expression and functional features of Populus phytochrome (PHY) gene family as well as the transcriptional responses of Populus to the changes in R/FR light. Expression data indicated that PHYA is the predominant PHY in the dark grown Populus seedling whereas PHYBs are most abundant in mature tissue types. Out of three Populus PHYs, PHYA is light labile and localized to cytosol in dark whereas both PHYB1 and PHYB2 are light stable and are localized to nucleus in mesophyll protoplasts. When expressed in Arabidopsis, PHYB1 rescued Arabidopsis phyB mutant phenotype whereas PHYB2 did not, suggesting functional diversification between these two gene family members. However, phenotypes of transgenic Populus lines with altered expression of PHYB1, PHYB2 or both and the expression of candidate shade response genes in these transgenic lines suggest that PHYB1 and PHYB2 may have distinct yet overlapping functions. The RNAseq results and analysis of Populus exposed to enriched-FR light indicate that genes associated in cell wall modification and brassinosteroid signaling were induced under far red light. Overall our data indicate that Populus transcriptional responses are at least partially conserved with Arabidopsis.

  20. Table lamp with dynamically controlled lighting distribution and uniformly illuminated luminous shade

    SciTech Connect

    Siminovitch, Michael J.; Page, Erik R.

    2002-01-01

    A double lamp table or floor lamp lighting system has a pair of compact fluorescent lamps (CFLs) or other lamps arranged vertically, i.e. one lamp above the other, with a reflective septum in between. By selectively turning on one or both of the CFLs, down lighting, up lighting, or both up and down lighting is produced. The control system can also vary the light intensity from each CFL. The reflective septum ensures that almost all the light produced by each lamp will be directed into the desired light distribution pattern which is selected and easily changed by the user. In a particular configuration, the reflective septum is bowl shaped, with the upper CFL sitting in the bowl, and a luminous shade hanging down from the bowl. The lower CFL provides both task lighting and uniform shade luminance. Planar compact fluorescent lamps, e.g. circular CFLs, particularly oriented horizontally, are preferable. CFLs provide energy efficiency. However, other types of lamps, including incandescent, halogen, and LEDs can also be used in the fixture. The lighting system may be designed for the home, hospitality, office or other environments.

  1. Pinus sylvestris switches respiration substrates under shading but not during drought

    NASA Astrophysics Data System (ADS)

    Hartmann, Henrik; Fischer, Sarah; Hanf, Stefan; Frosch, Torsten; Poppp, Jürgen; Trumbore, Susan

    2015-04-01

    Reduced carbon assimilation during prolonged drought forces trees to rely on stored carbon to maintain vital processes like respiration. It has been shown, however, that the use of carbohydrates, a major carbon storage pool and main respiratory substrate in plants, strongly declines with deceasing plant hydration. Yet, no empirical evidence has been produced to what degree other carbon storage compounds like lipids and proteins may fuel respiration during drought. We exposed young scots pine trees to carbon limitation using either drought or shading and assessed respiratory substrate use by monitoring the respiratory quotient, δ13C of respired CO2and concentrations of the major storage compounds, i.e. carbohydrates (COH), lipids and amino acids. Generally, respiration was dominated by the most abundant substrate. Only shaded trees shifted from carbohydrate-dominated to lipid-dominated respiration and showed progressive carbohydrate depletion. In drought trees respiration was strongly reduced and fueled with carbohydrates from also strongly reduced carbon assimilation. Initial COH content was maintained during drought probably due to reduced COH mobilization and use and the maintained COH content may have prevented lipid catabolism via sugar signaling. Our results suggest that respiratory substrates other than carbohydrates are used under carbohydrate limitation but not during drought. Thus, respiratory substrate change cannot provide an efficient means to counterbalance carbon limitation under natural drought.

  2. Pinus sylvestris switches respiration substrates under shading but not during drought.

    PubMed

    Fischer, Sarah; Hanf, Stefan; Frosch, Torsten; Gleixner, Gerd; Popp, Jürgen; Trumbore, Susan; Hartmann, Henrik

    2015-08-01

    Reduced carbon (C) assimilation during prolonged drought forces trees to rely on stored C to maintain vital processes like respiration. It has been shown, however, that the use of carbohydrates, a major C storage pool and apparently the main respiratory substrate in plants, strongly declines with decreasing plant hydration. Yet no empirical evidence has been produced to what degree other C storage compounds like lipids and proteins may fuel respiration during drought. We exposed young scots pine trees to C limitation using either drought or shading and assessed respiratory substrate use by monitoring the respiratory quotient, δ(13) C of respired CO2 and concentrations of the major storage compounds, that is, carbohydrates, lipids and amino acids. Only shaded trees shifted from carbohydrate-dominated to lipid-dominated respiration and showed progressive carbohydrate depletion. In drought trees, the fraction of carbohydrates used in respiration did not decline but respiration rates were strongly reduced. The lower consumption and potentially allocation from other organs may have caused initial carbohydrate content to remain constant during the experiment. Our results suggest that respiratory substrates other than carbohydrates are used under carbohydrate limitation but not during drought. Thus, respiratory substrate shift cannot provide an efficient means to counterbalance C limitation under natural drought.

  3. Morphological acclimation to understory environments in Abies amabilis, a shade- and snow-tolerant conifer species of the Cascade Mountains, Washington, USA.

    PubMed

    Mori, Akira S; Mizumachi, Eri; Sprugel, Douglas G

    2008-05-01

    Light-related plasticity in a variety of crown morphology and within-tree characteristics was examined in sun and shade saplings of Abies amabilis Dougl. ex J. Forbes growing in two late-successional forests with different snow regimes in the Cascade Mountains of Washington, USA. Compared with sun saplings, shade saplings typically had broad flat crowns as a result of acclimation at several scales (needle, shoot, branch, crown and whole sapling). Shoots of shade saplings had a smaller needle mass per unit of stem length than shoots of sun saplings, a feature that enhances light-interception efficiency by reducing among-needle shading. The low annual rate of needle production by shade saplings was associated with a longer needle lifespan and slower needle turnover. Reduced needle production within a shoot was reflected at the branch level, with lateral branches of shade saplings having a smaller needle mass than branches of the same length of sun saplings. Reduced allocation to needles permits greater investment in branches and stems, which is necessary to support the horizontally expanding branch system characteristic of shade saplings. Mean branch age of shade saplings was significantly higher than that of sun saplings. Shade saplings had lower needle mass per unit of trunk biomass or total biomass, reflecting greater investment in the trunk as a support organ. Increased investment in support organs in shade was more evident in the snowier habitat. The observed morphological acclimation makes A. amabilis highly shade and snow-tolerant and thus able to dominate in many late-successional forests in snowy coastal mountain regions.

  4. Predator attack rate evolution in space: the role of ecology mediated by complex emergent spatial structure and self-shading.

    PubMed

    Messinger, Susanna M; Ostling, Annette

    2013-11-01

    Predation interactions are an important element of ecological communities. Population spatial structure has been shown to influence predator evolution, resulting in the evolution of a reduced predator attack rate; however, the evolutionary role of traits governing predator and prey ecology is unknown. The evolutionary effect of spatial structure on a predator's attack rate has primarily been explored assuming a fixed metapopulation spatial structure, and understood in terms of group selection. But endogenously generated, emergent spatial structure is common in nature. Furthermore, the evolutionary influence of ecological traits may be mediated through the spatial self-structuring process. Drawing from theory on pathogens, the evolutionary effect of emergent spatial structure can be understood in terms of self-shading, where a voracious predator limits its long-term invasion potential by reducing local prey availability. Here we formalize the effects of self-shading for predators using spatial moment equations. Then, through simulations, we show that in a spatial context self-shading leads to relationships between predator-prey ecology and the predator's attack rate that are not expected in a non-spatial context. Some relationships are analogous to relationships already shown for host-pathogen interactions, but others represent new trait dimensions. Finally, since understanding the effects of ecology using existing self-shading theory requires simplifications of the emergent spatial structure that do not apply well here, we also develop metrics describing the complex spatial structure of the predator and prey populations to help us explain the evolutionary effect of predator and prey ecology in the context of self-shading. The identification of these metrics may provide a step towards expansion of the predictive domain of self-shading theory to more complex spatial dynamics.

  5. Effects of light shading and climatic conditions on the metabolic behavior of flonicamid in red bell pepper.

    PubMed

    Jung, Da-I; Farha, Waziha; Abd El-Aty, A M; Kim, Sung-Woo; Rahman, Md Musfiqur; Choi, Jeong-Heui; Kabir, Md Humayun; Im, So Jeong; Lee, Young-Jun; Truong, Lieu T B; Shin, Ho-Chul; Im, Geon-Jae; Shim, Jae-Han

    2016-03-01

    The degradation behavior of flonicamid and its metabolites (4-trifluoromethylnicotinic acid (TFNA) and N-(4-trifluoromethylnicotinoyl) glycine (TFNG)) was evaluated in red bell pepper over a period of 90 days under glass house conditions, including high temperature, low and high humidity, and in a vinyl house covered with high density polyethylene light shade covering film (35 and 75%). Flonicamid (10% active ingredient) was applied (via foliar application) to all fruits, including those groups grown under normal conditions (glass house) or under no shade cover (vinyl house). Samples were extracted using a Quick, Easy, Cheap, Effective, Rugged, and Safe "QuEChERS" method and analyzed using liquid chromatography-tandem mass spectrometry (LC/MS/MS). The method performance, including linearity, recovery, limits of detection (LOD), and quantitation (LOQ), was satisfactory. Throughout the experimental period, the residual levels of flonicamid and TFNG were not uniform, whereas that of TFNA remained constant. The total sum of the residues (flonicamid and its metabolites) was higher in the vinyl house with shade cover than in the glass house, under various conditions. The total residues were significantly higher when the treatment was applied under high light shade (75%). The flonicamid half-life decreased from 47.2 days (under normal conditions) to 28.4 days (at high temperatures) in the glass house, while it increased from 47.9 days (no shade cover) to 66 days (75% light shading) in the vinyl house. High humidity leads to decreases in the total sum of flonicamid residues in red bell pepper grown in a glass house, because it leads to an increase in the rate of water loss, which in turn accelerates the volatilization of the pesticide. For safety reasons, it is advisable to grow red bell pepper under glass house conditions because of the effects of solar radiation, which increases the rate of flonicamid degradation into its metabolites.

  6. [Effects of shade and competition of Chenopodium album on photosynthesis, fluorescence and growth characteristics of Flaveria bidentis].

    PubMed

    Yang, Qing; Li, Jing-Shi; Guo, Ai-Ying; Qi, Yan-Ling; Li, Yan-Sheng; Zhang, Feng-Juan

    2014-09-01

    It is necessary to elucidate its growth mechanism in order to prevent and control the further spread of Flaveria bidentis, an invasive plant in China. The effects of shading (shading rate of 0, 50% and 80%, respectively) and planting pattern (single cropping of F. bidentis, single cropping of Chenopodium album and their intercropping) on germination rate, fluorescence characteristics and growth characteristics of the two plants were investigated. The results showed that moderate shading contributed to emergence rate, but emergence rate of F. bidentis was not uniform, which was one of important factors as a stronger invader. With the increasing light intensity, net photosynthetic rate (Pn), photochemical quenching (qP), electron transport rate of PS II (ETR), quantum yield of PS II (Y), non-photochemical quenching (qN), water use efficiency (WUE), shoot bio-mass rate (SMR), crown width (CW) and dry biomass (DM) increased, specific leaf area (SLA) decreased, LMR of F. bidentis significantly increased, LMR of C. album changed insignificantly, and the increment of DM of F. bidentis was higher than that of C. album. In 80% shade treatment, Pn and DM of F. bidentis were lower than those of C. album. In natural light treatment, Pn, qN, WUE and relative competitive index (RCI) were the highest, CW and DM of intercropped F. bidentis and Pn, Y of C. album were significantly lower than that of the respective single treatment. F. bidentis had higher light saturation point (LSP) and light compensation point (LCP). In conclusion, the shade-tolerant ability of F. bidentis was weaker than that of C. album, but it was reversed in natural light treatment. The two plants adapted to the weak light in 80% shade treatment by increasing SLA and decreasing LMR. F. bidentis improved competition under natural light by increasing SMR and decreasing CW.

  7. Effects of light shading and climatic conditions on the metabolic behavior of flonicamid in red bell pepper.

    PubMed

    Jung, Da-I; Farha, Waziha; Abd El-Aty, A M; Kim, Sung-Woo; Rahman, Md Musfiqur; Choi, Jeong-Heui; Kabir, Md Humayun; Im, So Jeong; Lee, Young-Jun; Truong, Lieu T B; Shin, Ho-Chul; Im, Geon-Jae; Shim, Jae-Han

    2016-03-01

    The degradation behavior of flonicamid and its metabolites (4-trifluoromethylnicotinic acid (TFNA) and N-(4-trifluoromethylnicotinoyl) glycine (TFNG)) was evaluated in red bell pepper over a period of 90 days under glass house conditions, including high temperature, low and high humidity, and in a vinyl house covered with high density polyethylene light shade covering film (35 and 75%). Flonicamid (10% active ingredient) was applied (via foliar application) to all fruits, including those groups grown under normal conditions (glass house) or under no shade cover (vinyl house). Samples were extracted using a Quick, Easy, Cheap, Effective, Rugged, and Safe "QuEChERS" method and analyzed using liquid chromatography-tandem mass spectrometry (LC/MS/MS). The method performance, including linearity, recovery, limits of detection (LOD), and quantitation (LOQ), was satisfactory. Throughout the experimental period, the residual levels of flonicamid and TFNG were not uniform, whereas that of TFNA remained constant. The total sum of the residues (flonicamid and its metabolites) was higher in the vinyl house with shade cover than in the glass house, under various conditions. The total residues were significantly higher when the treatment was applied under high light shade (75%). The flonicamid half-life decreased from 47.2 days (under normal conditions) to 28.4 days (at high temperatures) in the glass house, while it increased from 47.9 days (no shade cover) to 66 days (75% light shading) in the vinyl house. High humidity leads to decreases in the total sum of flonicamid residues in red bell pepper grown in a glass house, because it leads to an increase in the rate of water loss, which in turn accelerates the volatilization of the pesticide. For safety reasons, it is advisable to grow red bell pepper under glass house conditions because of the effects of solar radiation, which increases the rate of flonicamid degradation into its metabolites. PMID:26846294

  8. Effect of immersion into solutions at various pH on the color stability of composite resins with different shades

    PubMed Central

    Moon, Ji-Deok; Seon, Eun-Mi; Son, Sung-Ae; Jung, Kyoung-Hwa; Kwon, Yong-Hoon

    2015-01-01

    Objectives This study examined the color changes of a resin composite with different shades upon exposure to water with different pH. Materials and Methods Nanohybrid resin composites (Filtek Z350XT, 3M ESPE) with four different shades (A2, A3, B1, and B2) were immersed in water with three different pH (pH 3, 6, and 9) for 14 day. The CIE L*a*b* color coordinates of the specimens were evaluated before and after immersion in the solutions. The color difference (ΔE*) and the translucency parameter (TP) were calculated using the color coordinates. Results ΔE* ranged from 0.33 to 1.58, and the values were affected significantly by the pH. The specimens immersed in a pH 6 solution showed the highest ΔE* values (0.87 - 1.58). The specimens with a B1 shade showed the lowest ΔE* change compared to the other shades. TP ranged from 7.01 to 9.46 depending on the pH and resin shade. The TP difference between before and after immersion in the pH solutions was less than 1.0. Conclusions The resulting change of color of the tested specimens did not appear to be clinically problematic because the color difference was < 1.6 in the acidic, neutral, and alkaline solutions regardless of the resin shade, i.e., the color change was imperceptible. PMID:26587412

  9. The skeleton buildup technique: a systematic approach to the three-dimensional control of shade and shape.

    PubMed

    McLaren, E A

    1998-01-01

    Due to the limitations of current shade-matching systems, shade communication has proven inadequate. Techniques for the fabrication of porcelain crowns that match the natural definition must address numerous factors. While all-ceramic restorations are indicated for the rehabilitation of the anterior dentition, these modalities are problematic in the restoration of teeth with discolored substrates. This article presents a systematic procedure for the three-dimensional fabrication of porcelain restorations. Techniques for building porcelain and altering the translucency of ceramic cores are also presented.

  10. Exposure Effects on the Productivity of Commercial Bombus impatiens (Hymenoptera: Apidae) Quads During Bloom in Watermelon Fields.

    PubMed

    Marchese, J I; Johnson, G J; Delaney, D A

    2015-08-01

    In light of population declines of honey bees (Apis mellifera L.), research has refocused attention on alternative pollinators and their potential to fulfill pollination services within economically important agricultural crops. Bumble bees are one such alternative, and within the past 20 yr, these pollinators have been reared and sold as commercial pollinators. Investigation into their use has been limited and more research is needed to improve pollinator effectiveness in field settings. Quad pollination units of the commercially reared native bumble bee species, the common eastern bumble bee (Bombus impatiens Cresson), were monitored and evaluated for productivity during peak watermelon [Citrullus lanatus (Thunberg) Matsumura & Nakai] bloom in southern Delaware. Differing colony exposures including various shade structure designs and natural shade were compared to assess the quality of the shade in regards to bumble bee activity during watermelon bloom. Quads receiving different nest treatments were evaluated on the basis of foraging activity and colony weight gain. Results indicated that colonies within quads provided with artificial or natural shade had significantly more foraging activity, weighed more, and produced more cells than colonies in quads placed in the field with no shade. Colonies within quads provided with artificial and natural shade peaked later in terms of foraging and weight gain, suggesting that growers could extend harvest to take advantage of later markets and possible movement into fields that were planted later. PMID:26470323

  11. Exposure Effects on the Productivity of Commercial Bombus impatiens (Hymenoptera: Apidae) Quads During Bloom in Watermelon Fields.

    PubMed

    Marchese, J I; Johnson, G J; Delaney, D A

    2015-08-01

    In light of population declines of honey bees (Apis mellifera L.), research has refocused attention on alternative pollinators and their potential to fulfill pollination services within economically important agricultural crops. Bumble bees are one such alternative, and within the past 20 yr, these pollinators have been reared and sold as commercial pollinators. Investigation into their use has been limited and more research is needed to improve pollinator effectiveness in field settings. Quad pollination units of the commercially reared native bumble bee species, the common eastern bumble bee (Bombus impatiens Cresson), were monitored and evaluated for productivity during peak watermelon [Citrullus lanatus (Thunberg) Matsumura & Nakai] bloom in southern Delaware. Differing colony exposures including various shade structure designs and natural shade were compared to assess the quality of the shade in regards to bumble bee activity during watermelon bloom. Quads receiving different nest treatments were evaluated on the basis of foraging activity and colony weight gain. Results indicated that colonies within quads provided with artificial or natural shade had significantly more foraging activity, weighed more, and produced more cells than colonies in quads placed in the field with no shade. Colonies within quads provided with artificial and natural shade peaked later in terms of foraging and weight gain, suggesting that growers could extend harvest to take advantage of later markets and possible movement into fields that were planted later.

  12. Effects of shade and root confinement on the expression of plagiotropic growth in juvenile-origin Douglas-fir rooted cuttings.

    PubMed

    Ritchie, G A; Keeley, J W; Ward, P A

    1997-07-01

    The purpose of this experiment was to determine why juvenile-origin Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) rooted cuttings, which remain plagiotropic (branchlike) when grown in containers in shaded glasshouses, become orthotropic (vertical) after they are transplanted to an outdoor environment. Plagiotropic rooted cuttings (mean angle from vertical = 45-50 degrees) from three full-sib families were transplanted into an outdoor nursery and subjected to four treatments consisting of a factorial of (1) shaded or unshaded and (2) bareroot or confined roots. After two growing seasons, treatments had significantly affected plant size and biomass in the order unshaded-bareroot > shaded-bareroot > unshaded-confined > shaded-confined, but plants in all treatments had become nearly orthotropic. It is concluded that neither shading nor root confinement is, but other glasshouse environmental conditions are, responsible for the persistence of plagiotropic growth.

  13. Davenport Ranges, Northern Territory, Australia, SRTM Shaded Relief and Colored Height

    NASA Technical Reports Server (NTRS)

    2005-01-01

    The Davenport Ranges of central Australia have been inferred to be among the oldest persisting landforms on Earth, founded on the belief that the interior of Australia has been tectonically stable for at least 700 million years. New rock age dating techniques indicate that substantial erosion has probably occurred over that time period and that the landforms are not nearly that old, but landscape evolution certainly occurs much slower here (at least now) than is typical across Earth's surface.

    Regardless of their antiquity, the Davenport Ranges exhibit a striking landform pattern as shown in this display of elevation data from the Shuttle Radar Topography Mission (SRTM). Quartzites and other erosion resistant strata form ridges within anticlinal (arched up) and synclinal (arched down) ovals and zigzags. These structures, if not the landforms, likely date back at least hundreds of millions of years, to a time when tectonic forces were active. Maximum local relief is only about 60 meters (about 200 feet), which is enough to contrast greatly with the extremely low relief surrounding terrain.

    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 northeast-southwest (image top to bottom) direction, so that northeast slopes appear bright and southwest 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

  14. Merged Shape from Shading and Shape from Stereo for Planetary Topographic Mapping

    NASA Astrophysics Data System (ADS)

    Tyler, Laurence; Cook, Tony; Barnes, Dave; Parr, Gerhard; Kirk, Randolph

    2014-05-01

    Digital Elevation Models (DEMs) of the Moon and Mars have traditionally been produced from stereo imagery from orbit, or from the surface landers or rovers. One core component of image-based DEM generation is stereo matching to find correspondences between images taken from different viewpoints. Stereo matchers that rely mostly on textural features in the images can fail to find enough matched points in areas lacking in contrast or surface texture. This can lead to blank or topographically noisy areas in resulting DEMs. Fine depth detail may also be lacking due to limited precision and quantisation of the pixel matching process. Shape from shading (SFS), a two dimensional version of photoclinometry, utilizes the properties of light reflecting off surfaces to build up localised slope maps, which can subsequently be combined to extract topography. This works especially well on homogeneous surfaces and can recover fine detail. However the cartographic accuracy can be affected by changes in brightness due to differences in surface material, albedo and light scattering properties, and also by the presence of shadows. We describe here experimental research for the Planetary Robotics Vision Data Exploitation EU FP7 project (PRoViDE) into using stereo generated depth maps in conjunction with SFS to recover both coarse and fine detail of planetary surface DEMs. Our Large Deformation Optimisation Shape From Shading (LDOSFS) algorithm uses image data, illumination, viewing geometry and camera parameters to produce a DEM. A stereo-derived depth map can be used as an initial seed if available. The software uses separate Bidirectional Reflectance Distribution Function (BRDF) and SFS modules for iterative processing and to make the code more portable for future development. Three BRDF models are currently implemented: Lambertian, Blinn-Phong, and Oren-Nayar. A version of the Hapke reflectance function, which is more appropriate for planetary surfaces, is under development

  15. Does Acacia dealbata express shade tolerance in Mediterranean forest ecosystems of South America?

    PubMed Central

    Aguilera, Narciso; Sanhueza, Carolina; Guedes, Lubia M; Becerra, José; Carrasco, Sebastián; Hernández, Víctor

    2015-01-01

    The distribution of Acacia dealbata Link (Fabaceae) in its non-native range is associated with disturbed areas. However, the possibility that it can penetrate the native forest during the invasion process cannot be ruled out. This statement is supported by the fact that this species has been experimentally established successfully under the canopy of native forest. Nonetheless, it is unknown whether A. dealbata can express shade tolerance traits to help increase its invasive potential. We investigated the shade tolerance of A. dealbata under the canopy of two native forests and one non-native for three consecutive years, as well as its early growth and photosynthetic performance at low light intensities (9, 30, and 70 μmol m−2sec−1) under controlled conditions. We found many A. dealbata plants surviving and growing under the canopy of native and non-native forests. The number of plants of this invasive species remained almost constant under the canopy of native forests during the years of study. However, the largest number of A. dealbata plants was found under the canopy of non-native forest. In every case, the distribution pattern varied with a highest density of plants in forest edges decreasing progressively toward the inside. Germination and early growth of A. dealbata were slow but successful at three low light intensities tested under controlled conditions. For all tested light regimes, we observed that in this species, most of the energy was dissipated by photochemical processes, in accordance with the high photosynthetic rates that this plant showed, despite the really low light intensities under which it was grown. Our study reveals that A. dealbata expressed shade tolerance traits under the canopy of native and non-native forests. This behavior is supported by the efficient photosynthetic performance that A. dealbata showed at low light intensities. Therefore, these results suggest that Mediterranean forest ecosystems of South America can become

  16. SRTM Colored Height and Shaded Relief: Sredinnyy Khrebet, Kamchatka Peninsula, Russia

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The Kamchatka Peninsula in eastern Russia is shown in this scene created from a preliminary elevation model derived from the first data collected during the Shuttle Radar Topography Mission (SRTM) on February 12, 2000. Sredinnyy Khrebet, the mountain range that makes up the spine of the peninsula, is a chain of active volcanic peaks. Pleistocene and recent glaciers have carved the broad valleys and jagged ridges that are common here. The relative youth of the volcanism is revealed by the topography as infilling and smoothing of the otherwise rugged terrain by lava, ash, and pyroclastic flows, particularly surrounding the high peaks in the south central part of the image. Elevations here range from near sea level up to 2,618 meters (8,590 feet).

    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 white at the highest elevations.

    Elevation data used in this image was acquired by the Shuttle Radar Topography Mission (SRTM) aboard 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 Space Shuttle Endeavour in 1994. SRTM was designed to collect three-dimensional measurements of 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 Aeronautics and Space Administration (NASA), the National Imagery and Mapping Agency (NIMA) of the U.S. Department of Defense, and the German and Italian space

  17. Does Acacia dealbata express shade tolerance in Mediterranean forest ecosystems of South America?

    PubMed

    Aguilera, Narciso; Sanhueza, Carolina; Guedes, Lubia M; Becerra, José; Carrasco, Sebastián; Hernández, Víctor

    2015-08-01

    The distribution of Acacia dealbata Link (Fabaceae) in its non-native range is associated with disturbed areas. However, the possibility that it can penetrate the native forest during the invasion process cannot be ruled out. This statement is supported by the fact that this species has been experimentally established successfully under the canopy of native forest. Nonetheless, it is unknown whether A. dealbata can express shade tolerance traits to help increase its invasive potential. We investigated the shade tolerance of A. dealbata under the canopy of two native forests and one non-native for three consecutive years, as well as its early growth and photosynthetic performance at low light intensities (9, 30, and 70 μmol m(-2)sec(-1)) under controlled conditions. We found many A. dealbata plants surviving and growing under the canopy of native and non-native forests. The number of plants of this invasive species remained almost constant under the canopy of native forests during the years of study. However, the largest number of A. dealbata plants was found under the canopy of non-native forest. In every case, the distribution pattern varied with a highest density of plants in forest edges decreasing progressively toward the inside. Germination and early growth of A. dealbata were slow but successful at three low light intensities tested under controlled conditions. For all tested light regimes, we observed that in this species, most of the energy was dissipated by photochemical processes, in accordance with the high photosynthetic rates that this plant showed, despite the really low light intensities under which it was grown. Our study reveals that A. dealbata expressed shade tolerance traits under the canopy of native and non-native forests. This behavior is supported by the efficient photosynthetic performance that A. dealbata showed at low light intensities. Therefore, these results suggest that Mediterranean forest ecosystems of South America can become

  18. Photosynthetic acclimation of overstory Populus tremuloides and understory Acer saccharum to elevated atmospheric CO2 concentration: interactions with shade and soil nitrogen.

    PubMed

    Kubiske, Mark E; Zak, Donald R; Pregitzer, Kurt S; Takeuchi, Yu

    2002-04-01

    We exposed Populus tremuloides Michx. and Acer saccharum Marsh. to a factorial combination of ambient and elevated atmospheric CO2 concentrations ([CO2]) and high-nitrogen (N) and low-N soil treatments in open-top chambers for 3 years. Our objective was to compare photosynthetic acclimation to elevated [CO2] between species of contrasting shade tolerance, and to determine if soil N or shading modify the acclimation response. Sun and shade leaf responses to elevated [CO2] and soil N were compared between upper and lower canopy leaves of P. tremuloides and between A. saccharum seedlings grown with and without shading by P. tremuloides. Both species had higher leaf N concentrations and photosynthetic rates in high-N soil than in low-N soil, and these characteristics were higher for P. tremuloides than for A. saccharum. Electron transport capacity (Jmax) and carboxylation capacity (Vcmax) generally decreased with atmospheric CO2 enrichment in all 3 years of the experiment, but there was no evidence that elevated [CO2] altered the relationship between them. On a leaf area basis, both Jmax and Vcmax acclimated to elevated [CO2] more strongly in shade leaves than in sun leaves of P. tremuloides. However, the apparent [CO2] x shade interaction was largely driven by differences in specific leaf area (m2 g-1) between sun and shade leaves. In A. saccharum, photosynthesis acclimated more strongly to elevated [CO2] in sun leaves than in shade leaves on both leaf area and mass bases. We conclude that trees rooted freely in the ground can exhibit photosynthetic acclimation to elevated [CO2], and the response may be modified by light environment. The hypothesis that photosynthesis acclimates more completely to elevated [CO2] in shade-tolerant species than in shade-intolerant species was not supported.

  19. Flower abscission in Vitis vinifera L. triggered by gibberellic acid and shade discloses differences in the underlying metabolic pathways

    PubMed Central

    Domingos, Sara; Scafidi, Pietro; Cardoso, Vania; Leitao, Antonio E.; Di Lorenzo, Rosario; Oliveira, Cristina M.; Goulao, Luis F.

    2015-01-01

    Understanding abscission is both a biological and an agronomic challenge. Flower abscission induced independently by shade and gibberellic acid (GAc) sprays was monitored in grapevine (Vitis vinifera L.) growing under a soilless greenhouse system during two seasonal growing conditions, in an early and late production cycle. Physiological and metabolic changes triggered by each of the two distinct stimuli were determined. Environmental conditions exerted a significant effect on fruit set as showed by the higher natural drop rate recorded in the late production cycle with respect to the early cycle. Shade and GAc treatments increased the percentage of flower drop compared to the control, and at a similar degree, during the late production cycle. The reduction of leaf gas exchanges under shade conditions was not observed in GAc treated vines. The metabolic profile assessed in samples collected during the late cycle differently affected primary and secondary metabolisms and showed that most of the