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

PubMed

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

2011-02-01

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

Reliability and accuracy of four dental shade-matching devices.

PubMed

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

2009-03-01

There are several electronic shade-matching instruments available for clinical use, but the reliability and accuracy of these instruments have not been thoroughly investigated. The purpose of this in vitro study was to evaluate the reliability and accuracy of 4 dental shade-matching instruments in a standardized environment. Four shade-matching devices were tested: SpectroShade, ShadeVision, VITA Easyshade, and ShadeScan. Color measurements were made of 3 commercial shade guides (Vitapan Classical, Vitapan 3D-Master, and Chromascop). Shade tabs were placed in the middle of a gingival matrix (Shofu GUMY) with shade tabs of the same nominal shade from additional shade guides placed on both sides. Measurements were made of the central region of the shade tab positioned inside a black box. For the reliability assessment, each shade tab from each of the 3 shade guide types was measured 10 times. For the accuracy assessment, each shade tab from 10 guides of each of the 3 types evaluated was measured once. Differences in reliability and accuracy were evaluated using the Standard Normal z test (2 sided) (alpha=.05) with Bonferroni correction. Reliability of devices was as follows: ShadeVision, 99.0%; SpectroShade, 96.9%; VITA Easyshade, 96.4%; and ShadeScan, 87.4%. A significant difference in reliability was found between ShadeVision and ShadeScan (P=.008). All other comparisons showed similar reliability. Accuracy of devices was as follows: VITA Easyshade, 92.6%; ShadeVision, 84.8%; SpectroShade, 80.2%; and ShadeScan, 66.8%. Significant differences in accuracy were found between all device pairs (P<.001) for all comparisons except for SpectroShade versus ShadeVision (P=.033). Most devices had similar high reliability (over 96%), indicating predictable shade values from repeated measurements. However, there was more variability in accuracy among devices (67-93%), and differences in accuracy were seen with most device comparisons.

[Effect of ceramic thickness and resin cement shades on final color of heat-pressed ceramic veneers].

PubMed

Ren, D F; Zhan, K R; Chen, X D; Xing, W Z

2017-02-09

Objective: To analyze the effect of ceramic materials thickness and resin cement shades on the final color of ceramic veneers in the discolored teeth, and to investigate the color agreement of try-in pastes to the corresponding resin cements. Methods: Sixty artificial maxillary central incisor teeth (C2 shade) were used to simulate the natural discolored teeth and prepared according to veneer tooth preparation protocol. Veneers of different thickness in the body region (0.50 and 0.75 mm) were fabricated using ceramic materials (LT A2 shade, IPS e.max Press). The ceramic veneer specimens were bonded to the artificial teeth using the 6 shades of resin cements (Variolink Veneer: shades of LV-3, LV-2, HV+3; RelyX™ Veneer: shades of TR, A3, WO) ( n= 5). A clinical spectrophotometer was used to measure the color parameters of ceramic veneers at the cervical, body and incisal regions. Color changes of veneers before and after cementation were calculated and registered as ΔE1, and the changes between try-in paste and the corresponding resin cements were registered as ΔE2. Results: Three-way ANOVA indicated that ΔE1 and ΔE2 values were significantly affected by the ceramic thickness, resin cement shades and measuring regions ( P< 0.05). The ΔE1 values of six shades ranged from 0.59-8.27. The ΔE1 values were more than 2.72 when the ceramic veneers were cemented with resin cements in shades of HV+3 and WO. The ΔE2 values of six shades ranged from 0.60-2.56. The shades of HV+3, WO and A3 resin cements were more than 1.60. Conclusions: Different thickness of ceramic materials, resin cement shades and measuring regions could affect the final color of ceramic veneers. The color differences of some resin cements and corresponding try-in pastes might be observed in clinical practice.

Geometric and shading correction for images of printed materials using boundary.

PubMed

Brown, Michael S; Tsoi, Yau-Chat

2006-06-01

A novel technique that uses boundary interpolation to correct geometric distortion and shading artifacts present in images of printed materials is presented. Unlike existing techniques, our algorithm can simultaneously correct a variety of geometric distortions, including skew, fold distortion, binder curl, and combinations of these. In addition, the same interpolation framework can be used to estimate the intrinsic illumination component of the distorted image to correct shading artifacts. We detail our algorithm for geometric and shading correction and demonstrate its usefulness on real-world and synthetic data.

The Effect of Core and Veneering Design on the Optical Properties of Polyether Ether Ketone.

PubMed

Zeighami, S; Mirmohammadrezaei, S; Safi, M; Falahchai, S M

2017-12-01

This study aimed to evaluate the effect of core shade and core and veneering thickness on color parameters and translucency of polyether ether ketone (PEEK). Sixty PEEK discs (0.5 and 1 mm in thickness) with white and dentine shades were veneered with A2 shade indirect composite resin with 0.5, 1 and 1.5 mm thickness (n=5). Cores without the veneering material served as controls for translucency evaluation. Color parameters were measured by a spectroradiometer. Color difference (ΔE₀₀) and translucency parameters (TP) were computed. Data were analyzed using one-way ANOVA and Tukey's test (for veneering thickness) and independent t-test (for core shade and thickness) via SPSS 20.0 (p⟨0.05). Regarding the veneering thickness, white cores of 0.5 mm thickness showed significant differences in all color parameters. In white cores of 1 mm thickness and dentine cores of 0.5 and 1 mm thickness, there were statistically significant differences only in L∗, a∗ and h∗. The mean TP was significantly higher in all white cores of 1 mm thickness than dentine cores of 1 mm. Considering ΔE₀₀=3.7 as clinically unacceptable, only three groups had higher mean ΔE₀₀ values. Core shade, core thickness, and the veneering thickness affected the color and translucency of PEEK restorations. Copyright© 2017 Dennis Barber Ltd.

The effect of different shades of specific luting agents and IPS empress ceramic thickness on overall color.

PubMed

Terzioğlu, Hakan; Yilmaz, Burak; Yurdukoru, Bengul

2009-10-01

The color stability of both porcelain and luting materials is very important for the esthetics of laminate veneers and all-ceramic crowns. The purpose of this study was to determine the effect of different shades of resin-based luting cement and the thickness of IPS Empress ceramics on the final color of the restorations. Resin-based dual-polymerized composite cement in two different shades (RelyX ARC) and ceramic disks of different thicknesses were selected for the study. Forty specimens (ten each of four different thicknesses: 0.5 mm, 1 mm, 2 mm, and 3 mm) were used for the evaluation. Initial specimen color parameters were determined in a Commission Internationale de l'Eclairage L*a*b* color order system with a colorimeter. Two different shades of the cement were prepared as polymerized layers and applied to one face of the specimens in order. Color changes were calculated between baseline color measurements and measurements after cementation. Color difference data were analyzed statistically. All specimens showed a significant color shift (DE > 3.7) after cementation regardless of the cement shade. However, the differences in the cement shade did not significantly affect the final color of the ceramic specimens for any thickness, and color shifts were not perceivable between the different shades of cement. (Int J Periodontics Restorative Dent 2009;29:499-505.).

Influence of implant abutment material and ceramic thickness on optical properties.

PubMed

Jirajariyavej, Bundhit; Wanapirom, Peeraphorn; Anunmana, Chuchai

2018-05-01

Anterior shade matching is an essential factor influencing the esthetics of a ceramic restoration. Dentists face a challenge when the color of an implant abutment creates an unsatisfactory match with the ceramic restoration or neighboring teeth. The purpose of this in vitro study was to evaluate the influence of abutment material and ceramic thickness on the final color of different ceramic systems. Four experimental and control ceramic specimens in shade A3 were cut from IPS e.max CAD, IPS Empress CAD, and VITA Suprinity PC blocks. These specimens had thicknesses of 1.0 mm, 1.5 mm, 2.0 mm, and 2.5 mm, respectively, for the experimental groups, and 4 mm for the controls. Background abutment specimens were fabricated to yield 3 different shades: white zirconia, yellow zirconia, and titanium at a 3-mm thickness. All 3 ceramic specimens in each thickness were placed in succession on different abutment backgrounds with glycerin optical fluid in between, and the color was measured. A digital spectrophotometer was used to record the specimen color value in the Commission Internationale De L'éclairage (CIELab) color coordinates system and to calculate the color difference (ΔE) between the control and experimental groups. The Kruskal-Wallis test was used to analyze the effect of ceramic thickness on different abutments, and the pair-wise test was used to evaluate within the group (α=.05). The color differences between the test groups and the control decreased with increasing ceramic thickness for every background material. In every case, significant differences were found between 1.0- and 2.5-mm ceramic thicknesses. Only certain 2.5-mm e.max CAD, VITA Suprinity PC, and Empress CAD specimens on yellow-shade zirconia or VITA Suprinity PC on titanium were identified as clinically acceptable (ΔE<3). Increasing ceramic restoration thickness over the abutment background decreased the color mismatch. Increasing the thickness of ceramic on a yellow-shaded zirconia abutment rather than on titanium or white zirconia yielded a more esthetic color for the whole restoration. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Effect of individual shades on reliability and validity of observers in colour matching.

PubMed

Lagouvardos, P E; Diamanti, H; Polyzois, G

2004-06-01

The effect of individual shades in shade guides, on the reliability and validity of measurements in a colour matching process is very important. Observer's agreement on shades and sensitivity/specificity of shades, can give us an estimate of shade's effect on observer's reliability and validity. In the present study, a group of 16 students, matched 15 shades of a Kulzer's guide and 10 human incisors to Kulzer's and/or Vita's shade tabs, in 4 different tests. The results showed shades I, B10, C40, A35 and A10 were those with the highest reliability and validity values. In conclusion, a) the matching process with shades of different materials was not accurate enough, b) some shades produce a more reliable and valid match than others and c) teeth are matched with relative difficulty.

Fiber optics reflectance spectroscopy (45°x: 45°) for color analysis of dental composite.

PubMed

Gargano, Marco; Ludwig, Nicola; Federighi, Veronica; Sykes, Ros; Lodi, Giovanni; Sardella, Andrea; Carrassi, Antonio; Varoni, Elena M

2016-08-01

To evaluate the application of a fiber optic reflectance spectroscopy (FORS) prototype probe for 45°x: 45° FORS for determining color of dental materials. A portable spectrophotometer with a highly manageable fiber optics co-axial probe was used to apply 45°x: 45° FORS for color matching in restorative dentistry. The color coordinates in CIELAB space of two dental shade guides and of the corresponding photopolymerized composites were collected and compared. The 45°x: 45° FORS with the co-axial probe (test system), the integrating sphere spectroscopy (reference system) and a commercial dental colorimeter (comparator system) were used to collect data and calculate color differences (ΔE and ΔE00). FORS system displayed high repeatability, reproducibility and accuracy. ΔE and ΔE00 values between the shade-guide, each other, and the corresponding composites resulted above the clinically acceptable limit. The 45°x: 45° FORS test system demonstrated suitable in vitro performance for dental composite color evaluation. 45°x: 45° fiber optic reflectance spectroscopy allows reliable color analysis of small surfaces of dental composites, favoring the color matching of material with the closely surrounding dental tissue, and confirming significant color differences between shade guide tabs and photo-polymerized composites.

Radiopacity of conventional, resin-modified glass ionomer, and resin-based luting materials.

PubMed

Tsuge, Takuma

2009-06-01

The purpose of the present study was to evaluate the radiopacity of currently available dental luting materials. Five conventional cements, six resin-modified glass ionomers (RMGIs), two methyl methacrylate (MMA)-based acrylic resins (eight shades), and nine composite luting materials were evaluated. Radiographs of the specimens were taken together with tooth slices and aluminum step wedges. The density of the specimens was determined with a densitometer and was expressed in terms of the equivalent thickness of aluminum per 2.0-mm unit thickness of specimen. The radiopacity values for human enamel and dentin were 4.3 and 2.3 mm Al/2.0 mm specimen, respectively. The values for materials ranged from 5.1 to 12.9 for conventional luting materials, from 3.4 to 6.3 for RMGIs, from less than 0.5 to 7.3 for MMA resins, and from 2.3 to 9.9 for the composite luting materials. A zinc phosphate cement showed the highest value (12.9), whereas five shades of MMA resin resulted in the lowest value (less than 0.5). Two RMGIs and three composite luting materials exhibited radiopacity values between those of enamel (4.3) and dentin (2.3). It can be concluded that the radiopacity value of luting materials varies considerably, and that care must be taken when selecting luting materials, considering the material composition of restorations.

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

PubMed

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

2018-04-20

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

The effect of coloring liquid dipping time on the fracture load and color of zirconia ceramics

PubMed Central

2017-01-01

PURPOSE The aims of the study were to evaluate the fracture load of zirconia core material after dipping in coloring liquid at different time intervals and to compare the color of dipped blocks with that of prefabricated shaded blocks. MATERIALS AND METHODS 3-unit bridge frameworks were designed digitally. Sixty frameworks were fabricated using uncolored zirconia blocks by CAD/CAM and divided into 4 groups randomly (n = 15). Group 2 (G2) was subjected to coloring liquids for 2 minutes, Group 4 (G4) for 4 minutes, and Group 6 (G6) for 6 minutes. CFS group was not subjected to any coloring procedure. After coloring, color differences between the test groups and a prefabricated shaded zirconia group (CPZ, n = 15) were evaluated by using a spectrophotometer. Fracture test was conducted immediately after shade evaluation with a Testometric test device at a cross-head speed of 1 mm/sec. Statistical analysis for evaluating color and fracture load was performed by using one way ANOVA followed by Tukey HSD test (P ≤ .05). Weibull analysis was conducted for distribution of fracture load. RESULTS There was no difference in terms of fracture load and color between CFS (1176.681 N) and G2 (985.638 N) group and between CPZ (81.340) and G2 (81.140) group, respectively. Fracture load values of G4 (779.340 N) and G6 (935.491 N) groups were statistically significantly lower than that of CFS group (P ≤ .005). The color values of G4 (79.340) and G6 (79.673) groups were statistically different than that of CPZ group (P ≤ .005). CONCLUSION Prolonged immersion of zirconia in coloring liquid not only negatively affected the fracture load of the zirconia being tested in the current study but also deteriorated the desired shade of the restoration. PMID:28243394

Effect of Shade and Light Curing Mode on the Degree of Conversion of Silorane-Based and Methacrylate-Based Resin Composites.

PubMed

Sm, Mousavinasab; M, Atai; N, Salehi; A, Salehi

2016-12-01

The degree of conversion depends on the material composition, light source properties, distance from light source, light intensity, curing time, and other factors such as shade and translucency. In the present study, we evaluated the effects of different light-curing modes and shades of methacrylate and silorane-based resin composites on the degree of conversion of resin composites (DC). The methacrylate-based (Filtek Z250, 3M, ESPE) and low-shrinkage silorane-based (Filtek P90, 3M, ESPE) resin composites were used in three groups as follows: group 1-Filtek Z250 (shade A3), group 2-Filtek Z250 (shade B2), and group 3-Filtek P90 (shade A3). We used a light-emitting diode (LED) curing unit for photopolymerization. 10 samples were prepared in each group to evaluate the degree of conversion; 5 samples were cured using soft-start curing mode, and the other 5 were cured using standard curing mode. The DC of the resin composites was measured using Fourier Transform Infrared Spectroscopy (FTIR). The data were analyzed using Kruskal Wallis and one-way ANOVA statistical tests. The degree of conversion of silorane-based resin composite was 70 - 75.8% and that of methacrylate-based resin composites was 60.2 - 68.2% (p = 0.009). The degree of conversion of the composite with brighter colour (B2) was statistically more than the darker composite (A3). Higher degree of conversion was achieved applying the standard curing mode. The results of the study showed that the colour and type of the resin composite and also the curing mode influence the degree of conversion of resin composites.

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.

Interactive rendering of acquired materials on dynamic geometry using frequency analysis.

PubMed

Bagher, Mahdi Mohammad; Soler, Cyril; Subr, Kartic; Belcour, Laurent; Holzschuch, Nicolas

2013-05-01

Shading acquired materials with high-frequency illumination is computationally expensive. Estimating the shading integral requires multiple samples of the incident illumination. The number of samples required may vary across the image, and the image itself may have high- and low-frequency variations, depending on a combination of several factors. Adaptively distributing computational budget across the pixels for shading is a challenging problem. In this paper, we depict complex materials such as acquired reflectances, interactively, without any precomputation based on geometry. In each frame, we first estimate the frequencies in the local light field arriving at each pixel, as well as the variance of the shading integrand. Our frequency analysis accounts for combinations of a variety of factors: the reflectance of the object projecting to the pixel, the nature of the illumination, the local geometry and the camera position relative to the geometry and lighting. We then exploit this frequency information (bandwidth and variance) to adaptively sample for reconstruction and integration. For example, fewer pixels per unit area are shaded for pixels projecting onto diffuse objects, and fewer samples are used for integrating illumination incident on specular objects.

Physiological responses of feedlot heifers provided access to different levels of shade

USDA-ARS?s Scientific Manuscript database

Heat stress has a significant impact on all livestock and poultry species causing economic losses and animal well-being concerns. Providing shade is one heat-abatement strategy that has been studied for years. Material selected to provide shade for animals greatly influences the overall stress reduc...

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.

Ranking the shade tolerance of forty-five candidate groundcovers for agroforestry plantings

Treesearch

J.W. Van Sambeek; N.E. Navarrete-Tindall; H.E. Garrett; C.-H. Lin; R.L. McGraw; D.C. Wallace

2007-01-01

Several large-scale screening trials evaluating native and introduced herbaceous ground covers have been conducted in the last half century. Most trials have used shade cloth to evaluate growth of potted plants under moderate shade (45 to 55 percent of full sunlight) similar to what might be found in many agroforestry practices and heavy shade (20 to 30 percent of full...

Evaluation of surface roughness and polishing techniques for new ceramic materials.

PubMed

Campbell, S D

1989-05-01

The surface roughness of crown and bridge materials should be minimized to obtain optimal biocompatability. This study used scanning electron microscopy to evaluate the effect of polishing procedures on two all-ceramic crown materials (Dicor and Cerestore). The "as formed," unpolished specimens of both Dicor and Cerestore materials presented a rough surface. It was found that any attempt to polish the Cerestore coping material resulted in an extremely rough surface. Finishing of the Dicor ceramic resulted in a smoother but pitted surface. Polishing of both ceramic materials resulted in a surface that was rougher than the glazed metal ceramic controls. The smoothest finish was obtained when the glazed veneer (Cerestore) and shading porcelain (Dicor) were applied to the all-ceramic materials.

Comparative color and surface parameters of current esthetic restorative CAD/CAM materials

PubMed Central

2018-01-01

PURPOSE The purpose of this study was to derive and compare the inherent color (hue angle, chroma), translucency (TPSCI), surface gloss (ΔE*SCE-SCI), and surface roughness (Ra) amongst selected shades and brands of three hybrid CAD/CAM blocks [GC Cerasmart (CS); Lava Ultimate (LU); Vita Enamic (VE)]. MATERIALS AND METHODS The specimens (N = 225) were prepared into square-shaped (12 × 12 mm2) with different thicknesses and shades. The measurements of color, translucency, and surface gloss were performed by a reflection spectrophotometer. The surface roughness and surface topography were assessed by white light interferometry. RESULTS Results revealed that hue and chroma values were influenced by the material type, material shade, and material thickness (P < .001). The order of hue angle amongst the materials was LU > CS > VE, whereas the order of chroma was VE > CS > LU. TPSCI results demonstrated a significant difference in terms of material types and material thicknesses (P ≤ .001). TPSCI values of the tested materials were ordered as LU > CS > VE. ΔE*SCE-SCI and Ra results were significantly varied amongst the materials (P < .001) and amongst the shades (P < .05). The order of ΔE*SCE-SCI amongst the materials were as follows LU > VE ≥ CS, whereas the order of Ra was CS ≥ VE > LU. CONCLUSION Nano-ceramic and polymer-infiltrated-feldspathic ceramic-network CAD/CAM materials exhibited different optical, inherent color and surface parameters. PMID:29503712

Assessment of color parameters of composite resin shade guides using digital imaging versus colorimeter.

PubMed

Yamanel, Kivanc; Caglar, Alper; Özcan, Mutlu; Gulsah, Kamran; Bagis, Bora

2010-12-01

This study evaluated the color parameters of resin composite shade guides determined using a colorimeter and digital imaging method. Four composite shade guides, namely: two nanohybrid (Grandio [Voco GmbH, Cuxhaven, Germany]; Premise [KerrHawe SA, Bioggio, Switzerland]) and two hybrid (Charisma [Heraeus Kulzer, GmbH & Co. KG, Hanau, Germany]; Filtek Z250 [3M ESPE, Seefeld, Germany]) were evaluated. Ten shade tabs were selected (A1, A2, A3, A3,5, A4, B1, B2, B3, C2, C3) from each shade guide. CIE Lab values were obtained using digital imaging and a colorimeter (ShadeEye NCC Dental Chroma Meter, Shofu Inc., Kyoto, Japan). The data were analyzed using two-way analysis of variance and Bonferroni post hoc test. Overall, the mean ΔE values from different composite pairs demonstrated statistically significant differences when evaluated with the colorimeter (p < 0.001) but there was no significant difference with the digital imaging method (p = 0.099). With both measurement methods in total, 80% of the shade guide pairs from different composites (97/120) showed color differences greater than 3.7 (moderately perceptible mismatch), and 49% (59/120) had obvious mismatch (ΔE > 6.8). For all shade pairs evaluated, the most significant shade mismatches were obtained between Grandio-Filtek Z250 (p = 0.021) and Filtek Z250-Premise (p = 0.01) regarding ΔE mean values, whereas the best shade match was between Grandio-Charisma (p = 0.255) regardless of the measurement method. The best color match (mean ΔE values) was recorded for A1, A2, and A3 shade pairs in both methods. When proper object-camera distance, digital camera settings, and suitable illumination conditions are provided, digital imaging method could be used in the assessment of color parameters. Interchanging use of shade guides from different composite systems should be avoided during color selection. © 2010, COPYRIGHT THE AUTHORS. JOURNAL COMPILATION © 2010, WILEY PERIODICALS, INC.

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

PubMed

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

2014-12-01

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

Comparative color and surface parameters of current esthetic restorative CAD/CAM materials.

PubMed

Egilmez, Ferhan; Ergun, Gulfem; Cekic-Nagas, Isil; Vallittu, Pekka Kalevi; Lassila, Lippo Veli Juhana

2018-02-01

The purpose of this study was to derive and compare the inherent color (hue angle, chroma), translucency (TP SCI ), surface gloss (ΔE * SCE-SCI ), and surface roughness (R a ) amongst selected shades and brands of three hybrid CAD/CAM blocks [GC Cerasmart (CS); Lava Ultimate (LU); Vita Enamic (VE)]. The specimens (N = 225) were prepared into square-shaped (12 × 12 mm 2 ) with different thicknesses and shades. The measurements of color, translucency, and surface gloss were performed by a reflection spectrophotometer. The surface roughness and surface topography were assessed by white light interferometry. Results revealed that hue and chroma values were influenced by the material type, material shade, and material thickness ( P < .001). The order of hue angle amongst the materials was LU > CS > VE, whereas the order of chroma was VE > CS > LU. TP SCI results demonstrated a significant difference in terms of material types and material thicknesses ( P ≤ .001). TP SCI values of the tested materials were ordered as LU > CS > VE. ΔE * SCE-SCI and R a results were significantly varied amongst the materials ( P < .001) and amongst the shades ( P < .05). The order of ΔE * SCE-SCI amongst the materials were as follows LU > VE ≥ CS, whereas the order of R a was CS ≥ VE > LU. Nano-ceramic and polymer-infiltrated-feldspathic ceramic-network CAD/CAM materials exhibited different optical, inherent color and surface parameters.

Responses of legumes and grasses to non-, moderate, and dense shade in Missouri, USA. II. Forage quality and its species-level plasticity

Treesearch

Kejia Pang; J.W. Van Sambeek; Nadia E. Navarrete-Tindall; Chung-Ho Lin; Shibu Jose; H. E. Garrett

2017-01-01

From a series of shade tolerance screening trials conducted in an outdoor Shade Tolerance Screening Laboratory, 22 forages (16 grasses and 6 legumes) were selected for quality evaluation. The forages were grown under non-shade (100% of full sun, the control), moderate shade (45%), and dense shade (20%) with adequate water and nutrients and free of competition from...

Reliability of conventional shade guides in teeth color determination.

PubMed

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

2013-10-01

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

Clinical evaluation of a new 10% carbamide peroxide tooth-whitening agent.

PubMed

Barnes, D M; Kihn, P W; Romberg, E; George, D; DePaola, L; Medina, E

1998-10-01

NUPRO Gold Tooth Whitening System was evaluated for efficacy according to the proposed ADA guidelines for acceptance. Sixty participants with discolored anterior teeth participated in a 14-day, double-blind, clinical trial. The participants were matched for age, gender, and oral health status and were given either a placebo gel without the active agent or the NUPRO Gold active gel, which they wore in a custom-fabricated mouth guard for home use. The shade of each participant's maxillary anterior teeth was evaluated using a value-oriented Vita Lumin Vacuum Shade Guide before the study. The same shade guide was used to determine shade changes. Time of use of the agent and potential side effects, such as tooth and gingival hypersensitivity and tissue irritation, were assessed at all recall examinations and were recorded by participants in daily diaries. The average shade change for the placebo users was less than one shade. The average shade change for the NUPRO Gold users was 6.96 shades. Tooth hypersensitivity varied from none to severe. Tissue irritation was minimal. The results of these evaluations indicate that NUPRO Gold is effective as a tooth-whitening system, when administered properly under the supervision of a dentist, with commonly reported side effects of transient tooth sensitivity and minimal gingival sensitivity. Little or no change in tissue health was noted. This study was supported by Dentsply Preventive Care (York, Pennsylvania).

Intrarater repeatability of shade selections with two shade guides.

PubMed

Hammad, Ihab A

2003-01-01

Color research has shown that shade guides do not always represent the color of natural teeth. Moreover, visual evaluation has been found to be unreliable and inconsistent. This investigation evaluated the effects of 2 shade guides on the intrarater repeatability (reliability) of prosthodontists and general practitioners with regard to shade selection. Ten prosthodontists and ten general practitioners (all men, 35-45 years old) with an average practice experience of 14 years participated in this study. Examiners were tested to eliminate color blindness. Each clinician used Vita Lumin Vacuum and Vitapan 3D-Master shade guides to determine the shades of the maxillary right canines of 20 patients following a standard protocol. The identification codes of the shade tabs were masked to prevent shade memory. All teeth were polished before each shade selection, and the selection process was standardized for controlled lighting and procedures. Shade selections were randomly repeated 1 month later by the same practitioners on the same group of patients in accordance with the same shade-selection protocol. Analysis of variance and t tests for individual comparisons among means were performed (P<.05). Significant interactions were found between the effects of shade guide system and specialty training on intrarater repeatability (P<.0001, analysis of variance). The intrarater repeatability of prosthodontists was significantly higher than that of general practitioners when the Vita Lumin Vacuum shade guide was used (P<.0001, t test). Use of the Vitapan 3D-Master shade guide significantly improved the intrarater repeatability of general practitioners compared with the Vita Lumin Vacuum shade guide (P<.0005). This improvement was not significant, however, among prosthodontists (P=.2861). Within the limitations of this study, the prosthodontists demonstrated superior intrarater repeatability in shade selection, especially when the Vita Lumin Vacuum shade guide was used. Use of the Vitapan 3D-Master shade guide notably improved intrarater repeatability among the general practitioners.

In vitro and in vivo evaluations of three computer-aided shade matching instruments.

PubMed

Yuan, Kun; Sun, Xiang; Wang, Fu; Wang, Hui; Chen, Ji-hua

2012-01-01

This study evaluated the accuracy and reliability of three computer-aided shade matching instruments (Shadepilot, VITA Easyshade, and ShadeEye NCC) using both in vitro and in vivo models. The in vitro model included the measurement of five VITA Classical shade guides. The in vivo model utilized three instruments to measure the central region of the labial surface of maxillary right central incisors of 85 people. The accuracy and reliability of the three instruments in these two evaluating models were calculated. Significant differences were observed in the accuracy of instruments both in vitro and in vivo. No significant differences were found in the reliability of instruments between and within the in vitro and the in vivo groups. VITA Easyshade was significantly different in accuracy between in vitro and in vivo models, while no significant difference was found for the other two instruments. Shadepilot was the only instrument tested in the present study that showed high accuracy and reliability both in vitro and in vivo. Significant differences were observed in the L*a*b* values of the 85 natural teeth measured using three instruments in the in vivo assessment. The pair-agreement rates of shade matching among the three instruments ranged from 37.7% to 48.2%, and the incidence of identical shade results shared by all three instruments was 25.9%. As different L*a*b* values and shade matching results were reported for the same tooth, a combination of the evaluated shade matching instruments and visual shade confirmation is recommended for clinical use.

Effects of elevated CO2 and shade on the decomposition of senesced tree foliage: impacts on microbial activity

Treesearch

Michael G. Kaufman; R. Malcolm Strand; Mark E. Kubiske; William J. Mattson; Daniel A. Herms; Edward D. Walker; Kurt S. Pregitzer; Richard W. Merritt

1996-01-01

We examined microbial respiration and carbon/nitrogen content of decomposing leaf material in microcosms used for growth studies of the treehole mosquito, Aedes triseriatus. Leaf material originated from birch and oak trees exposed to conditions of shade/sun and elevated/ambient levels of CO2. Microbial respiration as measured...

Cryomicrotome Applications: Techniques for the Study of Skeletal Materials.

DTIC Science & Technology

1983-09-01

Dehydrate rapidly and mount Results: collagen-blue ground substance of cartilage and bones-shades of blue mucus, amyloid, other hyaline substances-shades...AD-N±3? SiB CRYOMICROTOME AiPPLICATIONS: TECHNIQUES FOR THE STUDY OF i/i SKELETAL MATERIAL.-[I AIR FORCE AEROSPACE MEDICAL RESEARCH LAB WRIGHT...THE STUDY OF SKELETAL MATERIALS .% . , KATHERINE C. SMITH CLARENCE U. OLOFF LEON E. KAZARIAN A.7t SEPTEMBER 1083 4-Z LUJ Approved for public release

Evaluation of reliability and validity of three dental color-matching devices.

PubMed

Tsiliagkou, Aikaterini; Diamantopoulou, Sofia; Papazoglou, Efstratios; Kakaboura, Afrodite

2016-01-01

To assess the repeatability and accuracy of three dental color-matching devices under standardized and freehand measurement conditions. Two shade guides (Vita Classical A1-D4, Vita; and Vita Toothguide 3D-Master, Vita), and three color-matching devices (Easyshade, Vita; SpectroShade, MHT Optic Research; and ShadeVision, X-Rite) were used. Five shade tabs were selected from the Vita Classical A1-D4 (A2, A3.5, B1, C4, D3), and five from the Vita Toothguide 3D-Master (1M1, 2R1.5, 3M2, 4L2.5, 5M3) shade guides. Each shade tab was recorded 15 continuous, repeated times with each device under two different measurement conditions (standardized, and freehand). Both qualitative (color shade) and quantitative (L, a, and b) color characteristics were recorded. The color difference (ΔE) of each recorded value with the known values of the shade tab was calculated. The repeatability of each device was evaluated by the coefficient of variance. The accuracy of each device was determined by comparing the recorded values with the known values of the reference shade tab (one sample t test; α = 0.05). The agreement between the recorded shade and the reference shade tab was calculated. The influence of the parameters (devices and conditions) on the parameter ΔE was investigated (two-way ANOVA). Comparison of the devices was performed with Bonferroni pairwise post-hoc analysis. Under standardized conditions, repeatability of all three devices was very good, except for ShadeVision with Vita Classical A1-D4. Accuracy ranged from good to fair, depending on the device and the shade guide. Under freehand conditions, repeatability and accuracy for Easyshade and ShadeVision were negatively influenced, but not for SpectroShade, regardless of the shade guide. Based on the total of the color parameters assessed per device, SpectroShade was the most reliable of the three color-matching devices studied.

Shading reduces growth of longleaf and loblolly pine seedlings in containers

Treesearch

James P. Barnett

1989-01-01

Development of longleaf (Pinus palustris Mill.) and loblolly (P. taeda L.) pine seediings growing under three light conditions--full sunlight, 30% shade, and 50% shade--was evaluated. Although there was little difference between development of seedlings in 30% and 50% shade, those grown is full sunlight were signiticantly larger...

Effect of two fluoride varnishes on the color stability of three resin-based restorative materials: an in vitro study.

PubMed

Tafaroji, Raha; Biria, Mina; Ameri, Farhad; Torabzadeh, Hassan; Qahari, Pasha; Akbarzadeh Baghban, Alireza

2016-11-01

The aim of the present study was to evaluate the effect of two fluoride varnishes on color stability of three resin-based restorative materials. Fifty-four discs (14.5 × 1.7 mm) were fabricated from A2 and A3 shades of a compomer (F2000), a flowable composite (Z350), and a hybrid composite (Z250), and incubated at 37°C for 48 h. Dura Shield (colored) and Fluor Protector (colorless) fluoride varnishes were applied onto the discs. The coating was cleaned using a low-speed handpiece and nylon bristle brush after 24 h of storage in distilled water. A second coating was then applied. A control group with no coating was immersed in distilled water and used. The CIE L*a*b* color scale was measured before the treatments and following each cleaning utilizing a spectrophotometer. The colored fluoride varnish exhibited the highest overall color change (∆E) after the first and the second cleaning procedures in all the materials. Among these, the greatest color change was observed in the A3 shade of F2000, followed by the A3 shade of Z-250. The ∆E was less than 3.3 in all groups, and was therefore clinically acceptable. Color changes following the application of fluoride varnishes were found to be clinically acceptable in all groups. © 2015 Wiley Publishing Asia Pty Ltd.

Color related to ceramic and zirconia restorations: a review.

PubMed

Vichi, Alessandro; Louca, Chris; Corciolani, Gabriele; Ferrari, Marco

2011-01-01

The requirement to achieve natural looking restorations is one of the most challenging aspects of dentistry, and the shade matching of dental restorations with the natural dentition is a difficult task due to the complex optical characteristics of natural teeth. Dental porcelain is considered the reference material for prosthetic rehabilitation, but it is not easy to handle and aesthetic excellence is quite difficult to obtain. For these reasons, shade matching with dental porcelain is often considered to be more artistic than scientific. Shade matching is considered unpredictable due to several variables that may influence the final appearance of a restoration. In order to improve this situation, over the last decade new shade guides and instruments have been developed and the aesthetic aspects of dental porcelain have been further investigated. In this review some aspects of color selection and color reproduction have been examined. Color selection has advanced through the development of new shade guides and electronic shade taking devices, although visual assessment has still not been entirely replaced by electronic instruments. Color reproduction with dental porcelain has improved thanks to advances in the performance and knowledge of dental porcelain, but is still not easy to achieve. The difficulties of achieving good aesthetics with PFM restorations and the desire for metal free solutions have resulted in the increased use of zirconia. The unique optical properties of zirconia have introduced new opportunities for achieving superior aesthetics, however further research is required with this material. Copyright © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

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.

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

PubMed

Valtorta, S E; Leva, P E; Gallardo, M R

1997-11-01

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 artificial 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) degrees C, respectively. BGTs under all three shades were significantly lower (P < 0.01) than the average BGT recorded outside: 35.5 (SD 1.12) degrees C. Average BGTs in holding pens were 32.4 (SD 1.38) and 39.9 (SD 1.91) degrees C for shaded and non-shaded areas (P < 0.01). The corresponding average floor temperatures were 27.8 (SD 0.68) degrees C and 47.7 (SD 2.13) degrees 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) degrees C vs 39.3 (SD 0.42) degrees 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.

[Effects of shading on two Sphagnum species growth and their interactions].

PubMed

Ma, Jin-Ze; Bu, Zhao-Jun; Zheng, Xing-Xing; Li, Shan-Lin; Zeng, Jing; Zhao, Gao-Lin

2012-02-01

Taking Sphagnum palustre and S. fallax as test materials, this paper studied their growth and interactions under shading. In monoculture, shading promoted the height growth of S. palustre markedly, but had no effect on the growth of S. fallax and the biomass and branching of S. palustre. In mixed culture, S. fallax suppressed the increase of biomass and branching of S. palustre, while S. palustre had no effects on S. fallax. With the increase of shading stress, the competition of neighbour on S. fallax intensified. When the stress increased further, neighbor effect on S. fallax tended to be positive. However, the effect of neighbour on S. palustre was always competitive and did not change with the increase of shading stress.

Prevalence of Tooth Shade and its Correlation with Skin Colour - A Cross-sectional Study.

PubMed

Vadavadagi, Suneel V; Kumari, K V Halini; Choudhury, Gopal Krishna; Vilekar, Abhishek Madhukar; Das, Sitansu Sekhar; Jena, Debkant; Kataraki, Bharat; B L, Bhavana

2016-02-01

Aesthetics has become an important issue in modern society. Tooth shade is one of the factors in determining aesthetics. Studies have revealed that tooth shade is influenced by age, gender, eye colour, skin colour and other factors. The present study was aimed to assess the prevalence of tooth shade and its correlation with skin colour. A total of 300 subjects aged 18-20 years were evaluated for tooth shade using Vitapan - 3D shade guide. Anterior teeth were checked under natural light and facial skin colour by Lakme liquid foundation make up as a shade guide. Data was analysed using chi square test and spearman's correlation. Out of 300 students, 114 (38.00%) had A2 tooth shade; the least prevalent tooth shade among Chitradurga population was C1 (4.00%). There was a positive correlation between tooth shade and skin colour which was found to be statistically significant (p <0.05). The most prevalent tooth shade among Chitradurga population was A2 and least was C1. There was a significant correlation between tooth shade and skin colour with lighter skin tone subjects having lighter tooth shade hence skin colour can be used as a guide for shade selection.

Effects of shade tab arrangement on the repeatability and accuracy of shade selection.

PubMed

Yılmaz, Burak; Yuzugullu, Bulem; Cınar, Duygu; Berksun, Semih

2011-06-01

Appropriate and repeatable shade matching using visual shade selection remains a challenge for the restorative dentist. The purpose of this study was to evaluate the effect of different arrangements of a shade guide on the repeatability and accuracy of visual shade selection by restorative dentists. Three Vitapan Classical shade guides were used for shade selection. Seven shade tabs from one shade guide were used as target shades for the testing (A1, A4, B2, B3, C2, C4, and D3); the other 2 guides were used for shade selection by the subjects. One shade guide was arranged according to hue and chroma and the second was arranged according to value. Thirteen male and 22 female restorative dentists were asked to match the target shades using shade guide tabs arranged in the 2 different orders. The sessions were performed twice with each guide in a viewing booth. Collected data were analyzed with Fisher's exact test to compare the accuracy and repeatability of the shade selection (α=.05). There were no significant differences observed in the accuracy or repeatability of the shade selection results obtained with the 2 different arrangements. When the hue/chroma-ordered shade guide was used, 58% of the shade selections were accurate. This ratio was 57.6% when the value-ordered shade guide was used. The observers repeated 55.5% of the selections accurately with the hue/chroma-ordered shade guide and 54.3% with the value-ordered shade guide. The accuracy and repeatability of shade selections by restorative dentists were similar when different arrangements (hue/chroma-ordered and value-ordered) of the Vitapan Classical shade guide were used. Copyright © 2011 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Reliability of visual and instrumental color matching.

PubMed

Igiel, Christopher; Lehmann, Karl Martin; Ghinea, Razvan; Weyhrauch, Michael; Hangx, Ysbrand; Scheller, Herbert; Paravina, Rade D

2017-09-01

The aim of this investigation was to evaluate intra-rater and inter-rater reliability of visual and instrumental shade matching. Forty individuals with normal color perception participated in this study. The right maxillary central incisor of a teaching model was prepared and restored with 10 feldspathic all-ceramic crowns of different shades. A shade matching session consisted of the observer (rater) visually selecting the best match by using VITA classical A1-D4 (VC) and VITA Toothguide 3D Master (3D) shade guides and the VITA Easyshade Advance intraoral spectrophotometer (ES) to obtain both VC and 3D matches. Three shade matching sessions were held with 4 to 6 weeks between sessions. Intra-rater reliability was assessed based on the percentage of agreement for the three sessions for the same observer, whereas the inter-rater reliability was calculated as mean percentage of agreement between different observers. The Fleiss' Kappa statistical analysis was used to evaluate visual inter-rater reliability. The mean intra-rater reliability for the visual shade selection was 64(11) for VC and 48(10) for 3D. The corresponding ES values were 96(4) for both VC and 3D. The percentages of observers who matched the same shade with VC and 3D were 55(10) and 43(12), respectively, while corresponding ES values were 88(8) for VC and 92(4) for 3D. The results for visual shade matching exhibited a high to moderate level of inconsistency for both intra-rater and inter-rater comparisons. The VITA Easyshade Advance intraoral spectrophotometer exhibited significantly better reliability compared with visual shade selection. This study evaluates the ability of observers to consistently match the same shade visually and with a dental spectrophotometer in different sessions. The intra-rater and inter-rater reliability (agreement of repeated shade matching) of visual and instrumental tooth color matching strongly suggest the use of color matching instruments as a supplementary tool in everyday dental practice to enhance the esthetic outcome. © 2017 Wiley Periodicals, Inc.

Double-blind whitening Night-Guard study using ten percent carbamide peroxide.

PubMed

Ouellet, D; Los, S; Case, H; Healy, R

1992-01-01

The conservative technique of professionally dispensed and supervised, home-administered vital bleaching is now a routine treatment in the dental profession. This double-blind study evaluated the Rembrandt Lightening Gel and Whitening Toothpaste for shade change, colorimeter shade change. As well, it evaluated soft tissue health by periodontal probing, plaque index, and bleeding index. A patient questionnaire evaluated perception of whitening, perception of oral hygiene, average hours per day, and average days per week. Bleaching trays were worn over a 4-week period. The bleaching system showed definitive whitening effects as evaluated with the Vita shade guide and the colorimeter. The bleaching system had no deleterious effects on the soft tissue. The Rembrandt toothpaste alone demonstrated two-shade lightening. This vital bleaching system shows definitive whitening of the teeth in short periods of time with no adverse effects.

Influence of light source, polarization, education, and training on shade matching quality.

PubMed

Clary, Jacqueline A; Ontiveros, Joe C; Cron, Stanley G; Paravina, Rade D

2016-07-01

Many factors influence the quality of shade selection, and isolating how significantly each of these factors influences results is difficult. The purpose of this in vitro study was to compare results of shade matching using handheld lights with or without a polarizing filter with results obtained using a professional viewing booth and to analyze the influence of education and training on shade selection outcome. A total of 96 third-year dental students (evaluators) were randomly separated into 4 groups. Each group was assigned 1 of 2 handheld shade-matching devices (lights) with or without a polarizing filter. Each group performed a shade matching exercise using the handheld light or a professional viewing booth. The exercise consisted of matching shade tabs placed in a typodont to a commercial shade guide. Each group repeated this procedure 4 times over a 9-week period. A lecture on shade matching was presented at the fifth week of the study, between "before" and "after" shade matching procedures. Shade matching scores with handheld lights (7.8) were higher than scores of shade matching with the viewing booth (7.2). The mean scores for before (7.2) and after (7.8) shade matching (with education and training in between) were significantly different. The combined effect of light and education and training improved the shade matching score by 1.2, from 6.8 in the before sessions using the viewing booth to 8.0 in the after sessions using handheld lights. A 21% increase in the number of evaluators who selected 1 of 4 best matches was recorded, 10% for handheld lights versus viewing booth after education and training versus before sessions and 11% between after sessions using handheld lights versus before sessions using viewing booth. Within the limits of the study, the shade matching scores with handheld lights were significantly better than the results obtained using a viewing booth (P<.01). Using a handheld light with or without a polarizing filter did not influence shade matching results. Mean shade matching scores were significantly better after education and training (P<.01). Light combined with education and training resulted in the greatest increase in shade matching quality. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

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

PubMed

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

2007-09-01

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

Prevalence of Colour Vision Anomalies Amongst Dental Professionals and its Effect on Shade Matching of Teeth.

PubMed

Khosla, Amrit; Maini, Anuj Paul; Wangoo, Anuj; Singh, Sukhman; Mehar, Damanpreet Kaur

2017-01-01

The success of a restoration is dependent on accurate shade matching of teeth leading to studies evaluating the factors affecting the perception of shades. Colour vision anomalies including colour blindness have been found to exist in the population and it has been thought to be a potential factor affecting the colour perception ability. The present study was done to evaluate the prevalence of colour vision anomalies and its effect on matching of shades of teeth. A total of 147 dental professionals were randomly selected for the study and were first tested for visual acuity using the Snellen's Eye Chart so as to carry on the study with only those operators who had a vision of 6/6. Then, the Ishihara's colour charts were used to test the operators for colour vision handicap. In the last stage of the study, test for accuracy of shade selection was done using the Vitapan Classical shade guide. The shade guide tabs were covered to avoid bias. Percentage was used to calculate the prevalence of colour vision handicap and its effect on matching of shades of teeth as compared to normal vision, which was evaluated using Chi square test. Nineteen operators had colour vision anomalies out of hundred operators and only two operators presented with colour blindness. Colour vision anomaly was more prevalent than colour blindness and it was also found that it was more prevalent in males than females. The difference between the accuracy of shade matching between the operators with normal vision and colour vision defect and operators with normal vision and colour blindness was statistically not significant. Colour blindness and colour vision handicap are rare conditions, with the latter being more common in the population. According to our study, it was concluded that no statistically significant difference existed amongst the operators with normal vision and colour vision anomaly or operators with normal vision and colour blindness during the matching of shades of teeth.

Could digital imaging be an alternative for digital colorimeters?

PubMed

Caglar, Alper; Yamanel, Kivanc; Gulsahi, Kamran; Bagis, Bora; Ozcan, Mutlu

2010-12-01

This study evaluated the colour parameters of composite and ceramic shade guides determined using a colorimeter and digital imaging method with illuminants at different colour temperatures. Two different resin composite shade guides, namely Charisma (Heraeus Kulzer) and Premise (Kerr Corporation), and two different ceramic shade guides, Vita Lumin Vacuum (VITA Zahnfabrik) and Noritake (Noritake Co.), were evaluated at three different colour temperatures (2,700 K, 2,700-6,500 K, and 6500 K) of illuminants. Ten shade tabs were selected (A1, A2, A3, A3,5, A4, B1, B2, B3, C2 and C3) from each shade guide. CIE Lab values were obtained using digital imaging and a colorimeter (ShadeEye NCC Dental Chroma Meter, Shofu Inc.). The data were analysed using two-way ANOVA, and Pearson's correlation. While mean L* values of both composite and ceramic shade guides were not affected from the colour temperature, L* values obtained with the colorimeter showed significantly lower values than those of the digital imaging (p < 0.01). At combined 2,700-6500 K colour temperature, the means of a* values obtained from colorimeter and digital imaging did not show significant differences (p > 0.05). For both composite and ceramic shade guides, L* and b* values obtained from colorimeter and digital imaging method presented a high level of correlation. High-level correlations were also acquired for a* values in all shade guides except for the Charisma composite shade guide. Digital imaging method could be an alternative for the colorimeters unless the proper object-camera distance, digital camera settings and suitable illumination conditions could be supplied. However, variations in shade guides, especially for composites, may affect the correlation.

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

Oh, Seon-Hee; Kim, Seok-Gyu

2015-10-01

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

Shading Vita In-ceram YZ substructures: influence on value and chroma, part II.

PubMed

Devigus, A; Lombardi, G

2004-10-01

In this study, the influence of differently shaded substructures made of Y-TZP from different manufacturers (without, with 0.5 mm or 1.0 mm ceramic veneer with Vita VM9 Base Dentin) on the lightness, the saturation, and the color shade (= value, chroma, and hue) was measured and assessed with a spectral photometer (Easy Shade, Vita) on a clinical case in the mouth and on models of different color. Shading substructures made of Y-TZP facilitated adaptation to the basic shade and reduced the layer thickness of the veneer ceramic required to achieve the desired color. This should be done in the future as a matter of routine. In this way, tooth substance can be better conserved when preparing the teeth, and the esthetic result is not diminished. The material used for the production of the working models (plaster or plastic) should be tooth colored and in terms of lightness--analogous to the shading of the substructure--in order to facilitate clinical color measurement and quality control in the laboratory.

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. © The Author(s) 2014.

Effect of cross infection control barriers used on the light-curing device tips on the cure depth of a resin composite

PubMed Central

de Moraes Porto, Isabel Cristina Celerino; Ramos de Brito, Andréia Cristina; Parolia, Abhishek

2013-01-01

Background: Among the advice on prevent cross-infection was included usage of mechanical barriers on tips of photoactivation units. However, questions about the use of protective barriers placed on the light-curing unit's tips and the possibility of interference with the ability of guaranteeing an effective polymerization of composite resins need to be clarified. Aims: The aim of this study was to evaluate the effect of cross infection control barriers used on the light-curing device tips on the cure depth of composite resin. Materials and Methods: Power density measurements from the light-cure unit were recorded with a radiometer on ten separate occasions with different types and placement modes of each barrier (low-density polyethylene and polyvinyl chloride (PVC) film – smooth and folds) and no-barrier (control). Cure depth of TPH™ Spectrum™ resin, A2-A4, was evaluated by the scraping test. Statistical Analysis: The data were analyzed using Student's t-test or ANOVA one-way with Tukey's test (α =0.05). Results: Same type of barrier and different shades (A2, A4) of composite exhibited significant difference in the cure depth among all groups (P < 0.05). Both low-density polyethylene and PVC film folded barriers produced a significant reduction in the light intensity (P < 0.05). Conclusions: Regarding the resin shade, there was a significant reduction in the cure depth of A4 composite resin (dark shade) but this reduction is not enough to cause any adverse effect on the material's clinical performance. Therefore, disposable barriers can be recommended for use over the end of the light guide. PMID:23833455

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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 formore » 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.« less

[In vivo model to evaluate the accuracy of complete-tooth spectrophotometer for dental clinics].

PubMed

Liu, Feng; Yang, Jian; Xu, Tong-Kai; Xu, Ming-Ming; Ma, Yu

2011-02-01

To test ΔE between measured value and right value from the Crystaleye complete-tooth spectrophotometer, and to evaluate the accuracy rate of the spectrophotometer. Twenty prosthodontists participated in the study. Each of them used Vita 3D-Master shadeguide to do the shade matching, and used Crystaleye complete-tooth spectrophotometer (before and after the test training) tested the middle of eight fixed tabs from shadeguide in the dark box. The results of shade matching and spectrophotometer were recorded. The accuracy rate of shade matching and the spectrophotometer before and after training were calculated. The average accuracy rate of shade matching was 49%. The average accuracy rate of the spectrophotometer before and after training was 83% and 99%. The accuracy of the spectrophotometer was significant higher than that in shade matching, and training can improve the accuracy rate.

Cosmetic Dentistry

MedlinePlus

... want a whiter shade. ; Discoloration occurs in the enamel and can be caused by medication, coffee, tea ... on the desired shade you wish to achieve. Whitening in the office may call for one or more 45-minute to one-hour visits to your dentist's ... ; Bonding is tooth-colored material used to fill in gaps or ...

Comparative evaluation of performance measures for shading correction in time-lapse fluorescence microscopy.

PubMed

Liu, L; Kan, A; Leckie, C; Hodgkin, P D

2017-04-01

Time-lapse fluorescence microscopy is a valuable technology in cell biology, but it suffers from the inherent problem of intensity inhomogeneity due to uneven illumination or camera nonlinearity, known as shading artefacts. This will lead to inaccurate estimates of single-cell features such as average and total intensity. Numerous shading correction methods have been proposed to remove this effect. In order to compare the performance of different methods, many quantitative performance measures have been developed. However, there is little discussion about which performance measure should be generally applied for evaluation on real data, where the ground truth is absent. In this paper, the state-of-the-art shading correction methods and performance evaluation methods are reviewed. We implement 10 popular shading correction methods on two artificial datasets and four real ones. In order to make an objective comparison between those methods, we employ a number of quantitative performance measures. Extensive validation demonstrates that the coefficient of joint variation (CJV) is the most applicable measure in time-lapse fluorescence images. Based on this measure, we have proposed a novel shading correction method that performs better compared to well-established methods for a range of real data tested. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

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

PubMed

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

2018-01-01

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

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

NASA Astrophysics Data System (ADS)

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

2017-11-01

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

The Bionomics and Vector Competence of Anopheles Albimanus and Anopheles Vestitipennis in Southern Belize, Central America

DTIC Science & Technology

2000-11-20

can be found in large numbers throughout the Yucatan , southern Mexico and Guatemala (Kumm et at. 1943, Loyola et a1. 1991, Arredondo-Jimenez et a1...material or detritus as a nutritional source as well as plant cover for shade. Anopheles yestitipennis exhibits its highest numbers during the rainy...species appears to require plant material or detritus as a nutritional source as well as plant cover for shade. Both species also have a clear seasonal

Evaluating factors that affect the shade-matching ability of dentists, dental staff members and laypeople.

PubMed

Capa, Nuray; Malkondu, Ozlem; Kazazoglu, Ender; Calikkocaoglu, Senih

2010-01-01

The authors conducted a study to evaluate the influence of dentists' and nondentists' experience, age, sex, eye color and use of eyeglasses or contact lenses on tooth shade-matching ability. The authors included 120 participants in this study conducted in Istanbul (periodontists, oral and maxillofacial surgeons, orthodontists, endodontists, pediatric dentists, prosthodontists, restorative dentists, general dentists in private practice, dental technicians, dental assistants, dental assistant students and laypeople). The authors assigned participants to one of three groups: group 1 was composed of prosthodontists, restorative dentists and dental technicians; group 2 consisted of other dental specialists and general dentists; and group 3 included dental assistants, dental assistant students and laypeople. The authors asked participants to match the shades of three artificial maxillary right central incisors (Vitapan acrylic teeth [shades 2L1.5, 1M2, 2R1.5], Vita Zahnfabrik, Bad Säckingen, Germany) by using a shade guide system (Vita Toothguide 3D-Master, Vita Zahnfabrik). They calculated shade matching for the three color components (value, hue, chroma) and analyzed the results by using a chi(2) test. The rate of success in matching the shade for IM2 was 53.3 percent for participants in group 1, 30 percent for participants in group 2 and 20 percent for participants in group 3 (P = .017). However, there were no significant differences between the three groups for shades 2L1.5 and 2R1.5. Professional experience (P = .003) and age (P = .027) were associated with shade-matching success for tooth shade 2L1.5 only. The results showed no statistically significant differences with respect to sex, eye color or use of eyeglasses or contact lenses. Dental care professionals who routinely performed restorative procedures matched the shades better than did participants in other groups. Professional experience was associated positively with the outcome, while sex, eye color and use of eyeglasses or contact lenses did not have any effect on shade-matching results. To improve shade-matching skills, clinicians should participate in hands-on courses, continuing education classes and other training programs.

[Studies on the shade-endurance capacity of Glycyrrhiza uralensis].

PubMed

Wei, Sheng-li; Wang, Wen-quan; Chen, Xiu-hua; Qin, Shu-ying; Chen, Xiu-tian

2005-01-01

To study the shade-endurance property of Glycyrrhiza uralensis and provide rationale for the practice of inter-cropping G. uralensis with trees. Black shading nets were used to provide five different environments of light intensities (light penetration rates of 100%, 75%, 65%, 50% and 25%, respectively). To assess the shade-endurance capacity of G. uralensis, several aspects were evaluated, including growth characters, physiological and ecological characters, biomass, and chemical contents. G. uralensis is a light-favored plant. The growth indices such as plant height, stem diameter, leaves number, root diameter, biomass, and daily average photosynthetic rate (Pn) are highest when light permeation rate is 100%. All these indices decrease when light intensity decreases. However, G. uralensis possesses shade-endurance capacity to some degree; it adapts to the shading environment by increasing the leaf area and chlorophyll contents. Shading has no obvious effect on the absolute light energy utilization rate (Eu) or Fv/Fm ratio. The influence of shading on the chemical contents of G. uralensis is obvious.

Reliability and accuracy of Crystaleye spectrophotometric system.

PubMed

Chen, Li; Tan, Jian Guo; Zhou, Jian Feng; Yang, Xu; Du, Yang; Wang, Fang Ping

2010-01-01

to develop an in vitro shade-measuring model to evaluate the reliability and accuracy of the Crystaleye spectrophotometric system, a newly developed spectrophotometer. four shade guides, VITA Classical, VITA 3D-Master, Chromascop and Vintage Halo NCC, were measured with the Crystaleye spectrophotometer in a standardised model, ten times for 107 shade tabs. The shade-matching results and the CIE L*a*b* values of the cervical, body and incisal regions for each measurement were automatically analysed using the supporting software. Reliability and accuracy were calculated for each shade tab both in percentage and in colour difference (ΔE). Difference was analysed by one-way ANOVA in the cervical, body and incisal regions. range of reliability was 88.81% to 98.97% and 0.13 to 0.24 ΔE units, and that of accuracy was 44.05% to 91.25% and 1.03 to 1.89 ΔE units. Significant differences in reliability and accuracy were found between the body region and the cervical and incisal regions. Comparisons made among regions and shade guides revealed that evaluation in ΔE was prone to disclose the differences. measurements with the Crystaleye spectrophotometer had similar, high reliability in different shade guides and regions, indicating predictable repeated measurements. Accuracy in the body region was high and less variable compared with the cervical and incisal regions.

Evaluation of accuracy of shade selection using two spectrophotometer systems: Vita Easyshade and Degudent Shadepilot.

PubMed

Kalantari, Mohammad Hassan; Ghoraishian, Seyed Ahmad; Mohaghegh, Mina

2017-01-01

The aim of this in vitro study was to evaluate the accuracy of shade matching using two spectrophotometric devices. Thirteen patients who require a full coverage restoration for one of their maxillary central incisors were selected while the adjacent central incisor was intact. 3 same frameworks were constructed for each tooth using computer-aided design and computer-aided manufacturing technology. Shade matching was performed using Vita Easyshade spectrophotometer, Shadepilot spectrophotometer, and Vitapan classical shade guide for the first, second, and third crown subsequently. After application, firing, and glazing of the porcelain, the color was evaluated and scored by five inspectors. Both spectrophotometric systems showed significantly better results than visual method ( P < 0.05) while there were no significant differences between Vita Easyshade and Shadepilot spectrophotometers ( P < 0.05). Spectrophotometers are a good substitute for visual color selection methods.

Optical properties of paint-on resins for shade modification of crown and bridge resins--light transmittance characteristics--.

PubMed

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

2003-09-01

The purpose of this study was to examine the light transmittance characteristics of the paint-on resins for shade modification. Three shades of paint-on resin, one crown and bridge resin, and human enamel were used. Specimens with four different thicknesses (75-150 microm) were prepared. The light transmittances including its wavelength distribution and diffusion characteristics were measured. The color values and the color differences among thicknesses of specimens were also determined. The light transmittance values of the paint-on resins ranged from 60.3% to 88.3% at 100 microm thickness, which were lower or nearly equal in comparison with the crown and bridge resin and enamel. Although differences in the wavelength distribution of transmittance among materials were found at lower wavelengths, all materials showed similar diffusion characteristics. The thin layer of paint-on resin effectively changed the color of restorative resin. The paint-on resin may be an effective material for the modification of the color appearance matching required.

Lightness, chroma and hue differences on visual shade matching.

PubMed

Pecho, Oscar E; Pérez, María M; Ghinea, Razvan; Della Bona, Alvaro

2016-11-01

To analyze the influence of lightness, chroma and hue differences on visual shade matching performed by dental students. 100 dental students (DS) volunteers with normal vision participated in the study. A spectroradiometer (SP) was used to measure the spectral reflectance of 4 extracted human upper central incisors (UCI 1-4) and shade tabs from Vita Classical (VC) and Vita Toothguide 3D-Master (3D) shade guides. Measurements were performed over a gray background, inside a viewing booth and under D65 illuminant (diffuse/0° geometry). Color parameters (L*, a*, b*, C* and h°) were calculated. DS used VC and 3D to visually select the best shade match for each UCI. CIE metric differences (Δa * ,Δb * ,ΔL ' , ΔC ' and ΔH ' ) and CIEDE2000(2:1:1) lightness (ΔE L ), chroma (ΔE C ) and hue (ΔE H ) differences were obtained from each UCI and the first three shades selected by DS and the first option using CIELAB, CIEDE2000(1:1:1) and CIEDE2000(2:1:1) color difference metrics. The closest CIELAB color-discrimination ellipsoid (from RIT-DuPont visual color-difference data) to each UCI was selected for the analysis of visual shade matching. DS showed a preference for shades with lower chroma (ΔC ' and ΔE C ) and/or hue (ΔH ' and ΔE H ) values instead of shades with lower lightness values (ΔL ' and ΔE L ). Most best visual matches were near the tolerance ellipsoid centered on tooth shade. This study is an attempt to partially explain the inconsistencies between visual and instrumental shade matching and the limitations of shade guides. Visual shade matching was driven by color differences with lower chroma and hue values. Copyright © 2016 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Evaluating relationships among tree growth rate, shade tolerance, and browse tolerance following disturbance in an eastern deciduous forest

Treesearch

Lisa M. Krueger; Chris J. Peterson; Alejandro Royo; Walter P. Carson

2009-01-01

Interspecific differences in shade tolerance among woody species are considered a primary driving force underlying forest succession. However, variation in shade tolerance may be only one of many interspecific differences that cause species turnover. For example, tree species may differ in their sensitivity to herbivory. Nonetheless,...

Masking ability of a zirconia ceramic on composite resin substrate shades.

PubMed

Tabatabaian, Farhad; Shabani, Sima; Namdari, Mahshid; Sadeghpour, Koroush

2017-01-01

Masking ability of a restorative material plays an important role to cover discolored tooth structure; however, this ability has not yet been well understood in zirconia-based restorations. This study assessed the masking ability of a zirconia ceramic on composite resin substrates with different shades. Ten zirconia disc specimens, with 0.5 mm thickness and 10 mm diameter, were fabricated by a computer-aided design/computer-aided manufacturing system. A white substrate (control) and six composite resin substrates with different shades including A1, A2, A3, B2, C2, and D3 were prepared. The substrates had a cylindrical shape with 10 mm diameter and height. The specimens were placed onto the substrates for spectrophotometric evaluation. A spectrophotometer measured the L*, a*, and b* values for the specimens. ΔE values were calculated to determine the color differences between the groups and the control and then were compared with a perceptional threshold (ΔE = 2.6). Repeated measures ANOVA and Bonferroni tests were used for data analysis ( P < 0.05). The mean and standard deviation of ΔE values for A1, A2, A3, B2, C2, and D3 groups were 6.78 ± 1.59, 8.13 ± 1.66, 9.81 ± 2.64, 9.61 ± 1.38, 9.59 ± 2.63, and 8.13 ± 1.89, respectively. A significant difference was found among the groups in the ΔE values ( P = 0.006). The ΔE values were more than the perceptional threshold in all the groups ( P < 0.0001). Within the limitations of this study, it can be concluded that the tested zirconia ceramic could not thoroughly mask different shades of the composite resin substrates. Moreover, color masking of zirconia depends on the shade of substrate.

Mapping Geological Units on Mars by Analyzing the Spectral Properties of the Surface from the Mars-Express High Resolution Stereo Camera (HRSC)

NASA Astrophysics Data System (ADS)

Combe, J.; Adams, J. B.; McCord, T. B.

2006-12-01

Geological units at the surface of Mars can be investigated through the analysis of spatial changes of both its composition and its superficial structural properties. The color images provided by the High Resolution Stereo Camera (HRSC) are a multispectral dataset with an unprecedented high spatial resolution. We focused this study on the western chasmas of Valles Marineris with the neighboring plateau. Using the four-wavelength spectra of HRSC, the two types of surface color units (bright red and dark bluish material) plus a shade/shadow component can explain most of the variations [1]. An objective is to provide maps of the relative abundances that are independent of shade [2]. The spectral shape of the shade spectrum is calculated from the data. Then, Spectral Mixture Analysis of the two main materials and shade is performed. The shade gives us indications about variations in the surface roughness in the context of the mixtures of spectral/mineralogical materials. For mapping the different geological units at the surface at high spatial resolution, a correspondence between the color and the mineralogy is needed, aided by direct and more precise identifications of the composition of Mars. The joint analysis of HRSC and results from the OMEGA imaging spectrometer makes the most of their respective abilities [1]. Ferric oxides are present in bright red materials both in the chasmas and on the plateau [1] and they are often mixed with dark materials identified as basalts containing pyroxenes [4]. In Valles Marineris, salt deposits (bright) have been reported by using OMEGA [3], along with ferric oxides [4, 5] that appear relatively dark. The detailed spatial distribution of these materials is a key to understand the geology. Examples will be presented. [1] McCord T. B., et al. 2006, JGR, submitted. [2] Adams J. B. And Gillespie A. R., 2006, Cambridge University Press, 362 pp. [3] Le Mouelic S. et al., 2006, LPSC #1409. [4] Gendrin et al. (2005), LPSC #1858. [5] Gendrin A. et al., 2005, Science, 307, 1587-1591. [6] Le Deit et al., 2006, LPSC #2115.

[Effects of shading at different phases of grain-filling on wheat grain protein components contents and processing quality].

PubMed

Shi, Yu; Chen, Mao-xue; Yu, Zhen-wen; Xu, Zhen-zhu

2011-10-01

Taking three wheat cultivars Jimai 20 (strong gluten), Taishan 23 (medium gluten), and Ningmai 9 (weak gluten) as test materials, a field experiment was conducted to examine the effects of shading at different phases of grain-filling on the grain protein components contents and processing quality. Four treatments were installed, i. e., no shading (S0), shading at early grain-filling phase (from 0 day after anthesis (DAA) to 11 DAA; S1), shading at medium grain-filling phase (from 12 DAA to 23 DAA; S2), and shading at late grain-filling phase (from 24 DAA to 35 DAA; S3). No significant differences were observed in the grain albumin+globulin contents of the three cultivars among the four treatments. Shading increased the grain HMW-GS, LMW-GS, gluten, glutenin, and total protein contents of Jimai 20 and Taishan 23 significantly, and the increments were higher in treatment S2 than in other shading treatments. Treatments S2 and S3 increased the grain protein components contents of Ningmai 9 significantly. Comparing with the control, shading decreased the grain yield significantly, but increased the dough development time, dough stability time, and sedimentation volume, especially for treatment S2, which suggested that the wheat grain quality had a close relationship with the light intensity at medium phase of grain-filling. Overall, the regulation effect of shading at grain-filling stage on the wheat grain yield, grain protein components contents, and indices values of grain processing quality for the test cultivars was in the order of Jimai 20 > Taishan 23 > Ningmai 9.

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

PubMed

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

2018-04-01

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

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

USDA-ARS?s Scientific Manuscript database

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...

AVIAN RESOURCE USE IN DOMINICAN SHADE COFFEE PLANTATIONS

Treesearch

JOSEPH M. WUNDERLE. JR; STEVEN C. LATTAA

1998-01-01

We quantified foraging behavior of 19 bird species in shade coffee plantations in the Dominican Republic to document and evaluate their use of food resources in the shade overstory relative to the coffee understory. All species were observed foraging in the Znga “era overstory, and 18 of the 19 species had median foraging heights significantly above the median maximum...

Effects of combining ozone and hydrogren peroxide on tooth bleaching: A clinical study.

PubMed

Al-Omiri, Mahmoud K; Hassan, Ra'ed S Abul; AlZarea, Bader K; Lynch, Edward

2016-10-01

The purpose of this study was to evaluate the efficiency of bleaching after combining ozone and 38% H2O2 in comparison to the sole use of 38% H2O2. Consecutive 26 participants (13 males and 13 females) were recruited into this study. They were randomly allocated into 2 groups (n=13 for each group). In group 1 (test group); the participants' upper anterior teeth were treated with 38% H2O2 for 20min then the teeth were exposed to ozone for 60s (healOzone(®) X4, KaVo Dental, Biberach, Germany). In group 2 (controls); the upper anterior teeth were treated with 20min of 38% H2O2 only. The shade of teeth was evaluated by recording the L* a* b* values and Vita Classic shades at study baseline and after bleaching in both groups. The statistically significant changes were set at P≤0.05. Tooth sensitivity and teeth shades were comparable between groups at study baseline (p>0.05). Controls reported more tooth sensitivity following bleaching (p<0.001). Teeth achieved better Vita shades, higher L* values (lighter shades), and lower a* and b* values (lighter shades) after bleaching in both groups (P≤0.05). However, teeth bleached with H2O2 and ozone achieved better Vita shades, higher L* values and lower a* values (lighter shades) than those bleached with H2O2 alone (p<0.001). Changes in b* values were not significantly different between groups. Bleaching with 38% H2O2 for 20min followed by 60s of ozone application would result in teeth with lighter shades than bleaching with 38% H2O2 alone. Copyright © 2016 Elsevier Ltd. All rights reserved.

Color characteristics of low-chroma and high-translucence dental resin composites by different measuring modes.

PubMed

Lee, Y K; Lim, B S; Kim, C W; Powers, J M

2001-01-01

The objective of the described research was the evaluation of the effects of the differences in the color-measuring geometry (SCE, SCI) and the standard illuminant on the color and color change after polymerization and thermocycling of resin composites. White, translucent, and conventional shades of two brands of resin composites were measured before and after polymerization and after thermocycling according to the CIE L*a*b* color scale on a reflection spectrophotometer with SCE and SCI geometry under the standard illuminants A, D65, and C. Under both SCE and SCI modes, the color differences (DeltaE*) of specimens between the values measured under illuminants A and D65 or A and C were larger than those between D65 and C in unpolymerized, polymerized, and thermocycled conditions. With SCE geometry, DeltaE* after polymerization of the white shade group was 8.7-9.8 under D65, and was higher than the conventional shade group (p < 0.05) in both materials. With SCE geometry, DeltaE* between polymerized and thermocycled white, translucent shade was 4.4-7.1 under D65. With SCI geometry, the results were in general agreement with those of SCE mode. After polymerization, DeltaE* measured under illuminant A was generally higher than that under D65 or C (p < 0.01). After thermocycling, the color change was different depending on the color-measuring geometry and standard illuminant. Copyright 2001 John Wiley & Sons, Inc.

[Study on the matching of the shade between beverage and modifying porcelain shade guide].

PubMed

Yao, Jiang-wu; Li, Shui-gen; Lin, Jin-ying

2007-10-01

To evaluate the matching of the shade between beverage and modifying porcelain shade guide according to Munsell color order system, thus to provide the reference basis for selecting modifying porcelain to mimic the stain of natural tooth by technician. The shade of Vita Akzent, Vita Interno, Shofu Vintage & Unibond and Noritake Super Porcelain EX-3 shade tabs as well as 15 kinds of beverage were measured according to Munsell color order system on Color-Eye 7000A spectrophotometer. The difference of the frequency of approximate hue, value, and chroma between shade tabs and beverage were compared by calculating the Fisher exact probabilities. The frequency of approximate hue between 4 kinds of shade tabs and 15 kinds of bev-erage was significant different (P<0.05), while the frequency of approximate value, and chroma was not significant different (P>0.05). Except the hue, the color distribution of 4 kinds of shade tabs was similar to that of 15 kinds of beverage. But the color of beverage also can be approximately matched by any kind of modifying porcelain by mixing porcelain powder of appropriate hue, value, and chroma.

Color-Matching and Blending-Effect of Universal Shade Bulk-Fill-Resin-Composite in Resin-Composite-Models and Natural Teeth.

PubMed

Abdelraouf, Rasha M; Habib, Nour A

2016-01-01

Objectives . To assess visually color-matching and blending-effect (BE) of a universal shade bulk-fill-resin-composite placed in resin-composite-models with different shades and cavity sizes and in natural teeth (extracted and patients' teeth). Materials and Methods . Resin-composite-discs (10 mm × 1 mm) were prepared of universal shade composite and resin-composite of shades: A1, A2, A3, A3.5, and A4. Spectrophotometric-color-measurement was performed to calculate color-difference (Δ E ) between the universal shade and shaded-resin-composites discs and determine their translucency-parameter (TP). Visual assessment was performed by seven normal-color-vision-observers to determine the color-matching between the universal shade and each shade, under Illuminant D65. Color-matching visual scoring (VS) values were expressed numerically (1-5): 1: mismatch/totally unacceptable, 2: Poor-Match/hardly acceptable, 3: Good-Match/acceptable, 4: Close-Match/small-difference, and 5: Exact-Match/no-color-difference. Occlusal cavities of different sizes were prepared in teeth-like resin-composite-models with shades A1, A2, A3, A3.5, and A4. The cavities were filled by the universal shade composite. The same scale was used to score color-matching between the fillings and composite-models. BE was calculated as difference in mean-visual-scores in models and that of discs. Extracted teeth with two different class I-cavity sizes as well as ten patients' lower posterior molars with occlusal caries were prepared, filled by universal shade composite, and assessed similarly. Results . In models, the universal shade composite showed close matching in the different cavity sizes and surrounding shades (4 ≤ VS < 5) (BE = 0.6-2.9 in small cavities and 0.5-2.8 in large cavities). In extracted teeth, there was good-to-close color-matching (VS = 3.7-4.4 in small cavities, BE = 2.5-3.2) (VS = 3-3.5, BE = 1.8-2.3 in large cavities). In patients' molars, the universal shade composite showed good-matching (VS = 3-3.3, BE = -0.9-2.1). Conclusions . Color-matching of universal shade resin-composite was satisfactory rather than perfect in patients' teeth.

Matching the optical properties of direct esthetic dental restorative materials to those of human enamel and dentin

NASA Astrophysics Data System (ADS)

Ragain, James Carlton, Jr.

One of the goals of the restorative dentist is to restore the appearance of the natural dentition. Clinical matching of teeth and restorative materials are seldom accurate and shade selection techniques are subjective. The first specific aim of this research was to characterize the optical absorption and scattering that occurs within enamel, dentin, and composite resin and compomer restorative materials and to relate those phenomena to translucency and color. The second aim was to evaluate small color differences among composite restorative materials which would be detectable by humans. The last aim was to lay the foundation for developing an improved model of specifying layers of dental restorative materials in order to match the translucency and color to those of human enamel. The Kubelka-Munk theory was validated for enamel, dentin, and the restorative materials. These tissues and materials were then characterized in terms of their color parameters. Tooth cores were also characterized in terms of color space parameters. Human subjects were evaluated for their abilities to discriminate small color differences in the dental composite resin materials. The following conclusions were derived from this study: (1) Kubelka-Munk theory accurately predicts the diffuse reflectance spectra of enamel, dentin, and the direct esthetic dental restorative materials studied. (2) Scattering and absorption coefficients of the dental tissues and esthetic restorative materials can be directly calculated from diffuse reflectance measurements of a uniformly thick slab of tissue/material using black and white backings and the appropriate refractive index. (3) For tooth cores, there is a positive correlation between L* and b* and a negative correlation between L* and a*. (4) The range of translucency parameters for the restorative materials studied does not match those of enamel and dentin. (5) None of the shades of the dental composite resin restorative materials studied fit into the dentin color space. (6) For the materials studied, the CMC (1:1) color difference formula gives a better receiver operating characteristic than the CIELAB or CMC (2:1) formulas for acceptance.

Achieving the desired colour in discoloured teeth, using leucite-based CAD-CAM laminate systems.

PubMed

Turgut, Sedanur; Bagis, Bora; Ayaz, Elif Aydogan

2014-01-01

To evaluate the cumulative effect of the abutment tooth and resin cement colour on the resultant optical properties of porcelain laminate veneers (PLVs) fabricated with leucite-based CAD/CAM blocks with different shades and thicknesses. A total of 224 ceramic specimens were prepared from the IPS Empress CAD with four different shades of HT-A1, LT-A1, MT-A1 and Bl-1. Resin composite discs were prepared with shade A3.5. For the cementation, 4 different shades of light-cure resin cements were chosen. L*, a*, and b* values, as well as the chroma (C) and hue (h) values of each cemented ceramic and the A1 shade table, were recorded. L*, Cab* and hab* values of the cemented ceramics were influenced by ceramic shade, ceramic thickness, cement shade, and interaction terms of the three variables. There were significant differences between the 1-mm-thick ceramic veneers that exhibited higher L* and lower Cab* values compared with veneers that were 0.5mm in thickness. Using the Tr shade cement resulted in lower L* and higher Cab* values for all thicknesses and ceramic shades, whereas the WO shade cement resulted in higher values. The selected colour of a laminate restoration is significantly affected by the ceramic shade, ceramic thickness and resin cement shade. Using the WO shade resin cement seems to be more effective in masking the discoloured abutment tooth. Clinicians should also select the translucency level of the ceramic block with the shade when a leucite-based CAD/CAM system is chosen to treat a discoloured tooth. Copyright © 2013 Elsevier Ltd. All rights reserved.

Shading Vita YZ substructures: influence on value and chroma, part I.

PubMed

Devigus, A; Lombardi, G

2004-07-01

All-ceramic restorations should reproduce as well as possible the color of the natural teeth to create a restoration in accordance with the esthetic wishes and ideas of the patient. The basic color of zirconium oxide is white to ivory. The color can be partially adapted by veneering it with ceramic materials. However, it would be better if the substructure could already be adapted to the basic color shade of the neighboring teeth. In this study, the influence of differently shaded frameworks made of Y-TZP by Vita and 3M ESPE and by Enrico Steger (without, with 0.5 mm, or with 1.0 mm ceramic veneer with Base Dentin) on the brightness, saturation, and color shade (= value, chroma, and hue) was measured and assessed with the aid of a spectral photometer (EasyShade, Vita) in a clinical case in the mouth and on the model. By adaptation to the basic shade, the shading of substructures made of Y-TZP can help to reduce the necessary layer thickness of the veneer ceramic to achieve the desired color and should be performed in the future as a matter of routine. In this way, more substance can be conserved when restoring the teeth without having to accept an impairment of the esthetic result.

Evaluation of the Aurora Application Shade Measurement Accuracy

DOE Office of Scientific and Technical Information (OSTI.GOV)

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.

Light quality characterization under climate screens and shade nets for controlled-environment agriculture.

PubMed

Kotilainen, Titta; Robson, T Matthew; Hernández, Ricardo

2018-01-01

Climate screens are typically used inside glass greenhouses to improve control of humidity and temperature, and thus reduce energy expenditure. Shade nets are more appropriate to use, either with or without polyethylene cladding, at locations less-reliant on climate control, but where protection against hail, wind and excessive solar radiation might be needed. In addition, insect screens and nets can be employed to hinder insect pests and other invertebrates entering either type of production environment, and to keep invertebrates used in pest management contained inside. Screens and nets both transmit sunlight in a wavelength-specific manner, giving them the potential to affect plant morphology and physiology. Screens and nets of various colours and nominal shading factors have been described and studied; however, detailed measurements of their spectral characteristics are scarce. We measured solar spectral photon-irradiance and its attenuation by climate screens, shade nets, insect nets, greenhouse glass, and polyethylene covers. Our aim was to elucidate the effects of different patterns, colours, and shading factors, on light quality in production environments. Our measurements reveal that there are large differences both in the fraction of global irradiance attenuated and spectral ratios received under materials that are otherwise superficially similar in terms of their appearance and texture. We suggest that the type of spectral characterization that we performed is required to fully interpret the results of research examining plant responses to different types of screen and net. These data on spectral irradiance would benefit material manufacturers, researchers, growers, and horticultural consultants, enabling material selection to better match the solutions sought by growers and their desired outcomes regarding plant performance.

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

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

PubMed

Hernandes, Daiana Kelly Lopes; Arrais, Cesar Augusto Galvão; Lima, Erick de; Cesar, Paulo Francisco; Rodrigues, José Augusto

2016-01-01

This in vitro study evaluated the effect of two different shades of resin cement (RC- A1 and A3) layer on color change, translucency parameter (TP), and chroma of low (LT) and high (HT) translucent reinforced lithium disilicate ceramic laminates. One dual-cured RC (Variolink II, A1- and A3-shade, Ivoclar Vivadent) was applied to 1-mm thick ceramic discs to create thin RC films (100 µm thick) under the ceramics. The RC was exposed to light from a LED curing unit. Color change (ΔE) of ceramic discs was measured according to CIEL*a*b* system with a standard illuminant D65 in reflectance mode in a spectrophotometer, operating in the light range of 360-740 nm, equipped with an integrating sphere. The color difference between black (B) and white (W) background readings was used for TP analysis, while chroma was calculated by the formula C*ab=(a*2+b*2)½. ΔE of 3.3 was set as the threshold of clinically unacceptable. The results were evaluated by two-way ANOVA followed by Tukey's post hoc test. HT ceramics showed higher ΔE and higher TP than LT ceramics. A3-shade RC promoted higher ΔE than A1-shade cement, regardless of the ceramic translucency. No significant difference in TP was noted between ceramic discs with A1- and those with A3-shade cement. Ceramic with underlying RC showed lower TP than discs without RC. HT ceramics showed lower chroma than LT ceramics, regardless of the resin cement shade. The presence of A3-shade RC resulted in higher chroma than the presence of A1-shade RC. Darker underlying RC layer promoted more pronounced changes in ceramic translucency, chroma, and shade of high translucent ceramic veneers. These differences may not be clinically differentiable.

Effect of ceramic thickness and cement shade on the final shade after bonding using the 3D master system: a laboratory study.

PubMed

Montero, Javier; Gómez-Polo, Cristina

2016-06-01

The final color of a ceramic restoration is influenced by both the ceramic thickness and the cement shade. This study aims to evaluate the color stability according to the 3D Master System of e.max ceramic discs after bonding with different shades of luting agents. A total of 120 e.max.Press 2M1 HT ceramic discs (60 discs of 1-mm thick and 60 discs of 0.5 mm thick) and three different values of Variolink Veneer cement were used (-3, 0, +3) for the cementation process. An Easyshade compact device was used to measure color shade tabs, according to the 3D Master System, on the discs both before and after the cementation protocols. Bivariate and multivariate analyses were carried out with the spss v.21. After bonding with the different luting agents, only 30% remained as 2M1: specifically, 22% of the thinner discs and 37.3% of the thicker discs. In general, the effect of bonding increased the value and the chroma of the shade to a significant extent. Regression analyses revealed that the most significant predictor for all color parameters was cement shade, the thinner disc group bonded with -3 cement being the most unstable subgroup. According to the 3D Master System, the shade of the luting agent was the main predictor of the final color. However, the final color seems to be somewhat unpredictable, at least according to the modulating factors evaluated in the present study.

Effect of radiation light characteristics on surface hardness of paint-on resin for shade modification.

PubMed

Arikawa, Hiroyuki; Kanie, Takahito; Fujii, Koichi; Ban, Seiji

2005-12-01

The purpose of this study was to investigate the effect of radiation light characteristics--of different types of clinical light-curing unit--on polymerization efficiency, as determined by the surface hardness of light-cured paint-on resins. Four shades of paint-on resin for shade modification of restorative resins were used. Materials were cured using one laboratory and three clinical light-curing units with different light sources, namely tungsten-halogen, LED, plasma arc, and xenon flash lamps. Knoop hardness measurements were taken at both the top and bottom surfaces of the specimens to assess the mechanical properties and degree of polymerization. Both LED and plasma arc light units caused significantly poorer surface hardness than the halogen and laboratory xenon lights. In addition, the transparent shade was more sensitive to surface hardness than other chromatic shades. Our results indicated that the polymerization efficiency of paint-on resin was significantly influenced by the radiation light characteristics of clinical light-curing units.

Shading aboveground L-joint and lap-joint tests : comparison of white pine and sugar maple test assemblies

Treesearch

Carol A. Clausen; Daniel L. Lindner

2011-01-01

Five-year performance ratings are presented for two types of untreated, uncoated wood joints (L and lap) in aboveground tests under shaded conditions. The effect of shading on moisture entrapment in pine and maple L and lap joints was evaluated in a moderate decay zone (Madison, Wisconsin). Variations were observed between wood species, visual ratings, joint type,...

Sacramento's parking lot shading ordinance: environmental and economic costs of compliance

Treesearch

E.G. McPherson

2001-01-01

A survey of 15 Sacramento parking lots and computer modeling were used to evaluate parking capacity and compliance with the 1983 ordinance requiring 50% shade of paved areas (PA) 15 years after development. There were 6% more parking spaces than required by ordinance, and 36% were vacant during peak use periods. Current shade was 14% with 44% of this amount provided by...

Evaluating a new shade for feedlot cattle performance and heat stress

USDA-ARS?s Scientific Manuscript database

Heat stress in cattle results in decreased feed intake, lower daily gain and potentially death in susceptible animals under intense conditions. A study was carried out during the summer of 2013 on the USDA-ARS U.S. Meat Animal Research Center feedlot evaluating the impact of shade on environmental c...

Reliability of shade selection using an intraoral spectrophotometer.

PubMed

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

2012-06-01

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

A Study on Possibility of Clinical Application for Color Measurements of Shade Guides Using an Intraoral Digital Scanner.

PubMed

Yoon, Hyung-In; Bae, Ji-Won; Park, Ji-Man; Chun, Youn-Sic; Kim, Mi-Ae; Kim, Minji

2016-11-07

To assess if color measurement with intraoral scanner correlates with digital colorimeter and to evaluate the possibility of application of a digital scanner for shade selection. The L*a*b* values of the five shade tabs (A1, A2, A3, A3.5, and A4) were obtained with an intraoral scanner (TRIOS Pod) and a colorimeter (ShadeEye). Both devices were calibrated according to the manufacturer's instructions before measurements. Color measurement values were compared with paired t-test, and a Pearson's correlation analysis was performed to evaluate the relationship of two methods. The L*a*b* values of the colorimeter were significantly different from those of the digital scanner (p < 0.001). The L* and b* values of both methods were strongly correlated with each other (both p < 0.05). The device repeatability in both methods were reported to be excellent (p < 0.05). Within the limitations of this study, color measurements with digital intraoral scanners and computer-assisted image analysis were in accordance with those of the colorimeter with respect to L* and b* values; however, all the coordinates of shade tabs were significantly different between two methods. The digital intraoral scanner may not be used as the primary method of color selection in clinical practices, considering significant differences in color parameters with colorimeter. The scanner's capability in shade selection should be further evaluated. © 2016 by the American College of Prosthodontists.

Flectofold—a biomimetic compliant shading device for complex free form facades

NASA Astrophysics Data System (ADS)

Körner, A.; Born, L.; Mader, A.; Sachse, R.; Saffarian, S.; Westermeier, A. S.; Poppinga, S.; Bischoff, M.; Gresser, G. T.; Milwich, M.; Speck, T.; Knippers, J.

2018-01-01

Smart and adaptive outer façade shading systems are of high interest in modern architecture. For long lasting and reliable systems, the abandonment of hinges which often fail due to mechanical wear during repetitive use is of particular importance. Drawing inspiration from the hinge-less motion of the underwater snap-trap of the carnivorous waterwheel plant (Aldrovanda vesiculosa), the compliant façade shading device Flectofold was developed. Based on computational simulations of the biological role-model’s elastic and reversible motion, the actuation principle of the plant can be identified. The enclosed geometric motion principle is abstracted into a simplified curved-line folding geometry with distinct flexible hinge-zones. The kinematic behaviour is translated into a quantitative kinetic model, using finite element simulation which allows the detailed analyses of the influence of geometric parameters such as curved-fold line radius and various pneumatically driven actuation principles on the motion behaviour, stress concentrations within the hinge-zones, and actuation forces. The information regarding geometric relations and material gradients gained from those computational models are then used to develop novel material combinations for glass fibre reinforced plastics which enabled the fabrication of physical prototypes of the compliant façade shading device Flectofold.

Influence of the color of composite resin foundation and luting cement on the final color of lithium disilicate ceramic systems.

PubMed

Dede, Doğu Ömür; Sahin, Onur; Özdemir, Oğuz Süleyman; Yilmaz, Burak; Celik, Ersan; Köroğlu, AySegül

2017-01-01

Lithium disilicate restorations are commonly used, particularly in the anterior region. The color of the underlying composite resin foundation (CRF) and luting cement may negatively affect the color of lithium disilicate ceramic restorations. The purpose of this in vitro study was to investigate the effect of CRF and resin cement materials on the color of lithium disilicate ceramics in 2 different translucencies. Twenty disks (11×1.5 mm, shade A2) were fabricated from medium-opacity (mo) (n=10) and high-translucency (ht) (n=10) lithium disilicate (Lds) blocks (IPS e.max Press). Five CRF disks (11×3 mm) were fabricated in 5 different shades (A1, A2, A3, B2, C2) and 30 resin cement disks (11×0.2 mm) in the shades of translucent (Tr), universal (Un=A2), and white-opaque (Wo). Ceramic specimens were placed on each CRF, and the resin cement combination and color was measured with a spectrophotometer. CIELAB color coordinates were recorded, and the color coordinates of both ceramics on the shades of the A2 CRF and resin cement were saved as the control. Color differences (ΔE 00 ) between the control and test groups were calculated. Data were analyzed with 3-way analysis ANOVA and compared with the Tukey HSD test (α=.05). The ΔE 00 values were influenced by the shades of the CRF, resin cement materials, and also their interactions (P<.05). The ΔE 00 values were not affected by the ceramic type. The ΔE 00 values of the Wo cement groups (1.73 to 2.96) were significantly higher than those of the other cement shades (0.88 to 1.29) for each ceramic type and CRF shade (P<.05). Lithium disilicate ceramics in 2 different translucencies were similarly influenced by the color of the underlying cement and CRF. When translucent and universal cement shades were used, the core shade did not affect the final color of the ceramics. White opaque cement caused clinically unacceptable color changes in both ceramics on all shades of CRFs except the C2 CRF and when high translucency ceramic was used on the A2 CRF. These changes were clinically acceptable, but perceptible. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Does gender and experience influence shade matching quality?

PubMed

Haddad, Helene J; Jakstat, Holger A; Arnetzl, Gerwin; Borbely, Judit; Vichi, Alessandro; Dumfahrt, Herbert; Renault, Patrick; Corcodel, Nicoleta; Pohlen, Bostjan; Marada, Gyula; de Parga, Juan A Martinez Vazquez; Reshad, Mamaly; Klinke, Thomas U; Hannak, Wolfgang B; Paravina, Rade D

2009-01-01

To evaluate the influence of gender and level of experience on shade matching quality. A study was simultaneously performed at 15 universities located in 9 countries. A total of 614 color normal participants completed all phases of the experiment. Among them, there were 305 females and 309 males, 319 dental students and 295 dental professionals. A lecture on color matching in dentistry was given to all participants. Initial training was performed using Toothguide Trainer software (TT), while Toothguide Training Box (TTB) was used for both training and testing of participants' shade matching results. The test task was to successively match 15 shade guide tabs with the corresponding shade guide. The shade matching score for each participant was computed as a sum of color differences (SigmaDeltaE(ab)(*) score) between target tabs and selected tabs. Lower scores corresponded to better shade matching results and vice versa. Means and standard deviations were calculated. Mann-Whitney U test was used for statistical analysis of the data (alpha=0.05). The mean shade matching score (S.D.) for all participants was 41 (21). The score for female and male participants was 38 (20) and 44 (21), respectfully (p<0.001). The difference in scores between dental students, 42 (20), and dental professionals, 39 (21), was not statistically significant. Within the limitations of this study, females achieved significantly better shade matching results than males, indicating that gender plays an important role in shade matching. The level of experience was not found to be significant factor in shade matching.

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

PubMed

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

2017-05-01

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

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

PubMed

Xu, Yingxin

2015-10-01

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

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

NASA Astrophysics Data System (ADS)

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

2009-10-01

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

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

NASA Astrophysics Data System (ADS)

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

2018-02-01

Shade intensity is one of the most important requirements for plant growth, affecting growth, development, survival, and crop productivity. This study aims to evaluate the growth and productiom of New Superior Rice Varieties In The shade Intensity. This study was conducted in Balai Pengkajian Teknologi Pertanian, Pagar Merbau, Deli Serdang, North Sumatra. The research used completely randomized design with twofactors. The shade intensity (N) were 25%, 50% and no shade intensity as a control. Whereas new superior rice varieties were V1: Inpara 2, V2: Suluttan Unsrat 2, V3: Inpari Mugibat, V4: Inpari Sidenuk, V5: Mekongga, V6: Ciherang, V7:Inpari 10, V8: Inpari 3, V9: Inpari 4, V10: Inpari 30, dan V11: Cibogo. The result indicated that new superior rice varietiesshowedsignificant effectonthe growth and productionvariablesuch as leaf area, where Inpari Sidenuk variety was the highest among the varieties. Total chorophyll, the highest was found on Inpari variety. Number of tillers and plant height where the highest was found on Ciherang variety. The shade intensity showed significant effect on leaf area, where 25% shade intensity was the highest. Total chlorophyll, the highest was found on 50% shade intensity, number of tillers, the highest was found on no shade intensity.

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

Evaluation of spectral light management on growth of container-grown willow oak, nuttall oak and summer red maple

USDA-ARS?s Scientific Manuscript database

Plant response to blue, red, gray or black shade cloth was evaluated with willow oak (Quercus phellos L.), Nuttall oak (Quercus nuttallii Palmer, Nuttall) and Summer Red maple (Acer rubrum L. ‘Summer Red’) liners. Light transmitted through the colored shade cloth had no influence on germination of ...

Evaluation of translucency of monolithic zirconia and framework zirconia materials

PubMed Central

Tuncel, İlkin; Üşümez, Aslıhan

2016-01-01

PURPOSE The opacity of zirconia is an esthetic disadvantage that hinders achieving natural and shade-matched restorations. The aim of this study was to evaluate the translucency of non-colored and colored framework zirconia and monolithic zirconia. MATERIALS AND METHODS The three groups tested were: non-colored framework zirconia, colored framework zirconia with the A3 shade according to Vita Classic Scale, and monolithic zirconia (n=5). The specimens were fabricated in the dimensions of 15×12×0.5 mm. A spectrophotometer was used to measure the contrast ratio, which is indicative of translucency. Three measurements were made to obtain the contrast ratios of the materials over a white background (L*w) and a black background (L*b). The data were analyzed using the one-way analysis of variance and Tukey HSD tests. One specimen from each group was chosen for scanning electron microscope analysis. The determined areas of the SEM images were divided by the number of grains in order to calculate the mean grain size. RESULTS Statistically significant differences were observed among all groups (P<.05). Non-colored zirconia had the highest translucency with a contrast ratio of 0.75, while monolithic zirconia had the lowest translucency with a contrast ratio of 0.8. The mean grain sizes of the non-colored, colored, and monolithic zirconia were 233, 256, and 361 nm, respectively. CONCLUSION The translucency of the zirconia was affected by the coloring procedure and the grain size. Although monolithic zirconia may not be the best esthetic material for the anterior region, it may serve as an alternative in the posterior region for the bilayered zirconia restorations. PMID:27350851

Comparison of shade matching by visual observation and an intraoral dental colorimeter.

PubMed

Li, Q; Wang, Y N

2007-11-01

The purpose of this study was to compare the applicability of two shade-matching approaches: Vintage Halo shade guide (visual method) and Shofu ShadeEye NCC colorimeter (instrumental method). Twenty participants' maxillary left central incisors were evaluated. Corresponding metal ceramic crowns were fabricated with each shade-matching approach. The colour distributions (L*, a* and b*) of the middle third region of each tooth and corresponding metal ceramic crowns were spectrophotometrically assessed. The colour difference (DeltaE) and colour distributions (DeltaL*, Deltaa* and Deltab*) between the tooth and the corresponding crowns were calculated. We found that the colour differences of both groups fell within the clinical unacceptable range (DeltaE > 2.75). Regarding DeltaE and the three colour distributions, no significant difference was found, expect for a* (P < 0.01). The shade matching difficulty degree was analysed through the agreements of visual shade selection. Within easy matching cases, the instrumental method achieved better results (P = 0.041). In conclusion, it is suggested that the reliability of shade matching can be ensured by neither the colorimeter nor the visual approach. However, the colorimeter can achieve better results within easy matching cases.

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.

Assessment of the influence of gender and skin color on the preference of tooth shade in Saudi population.

PubMed

Labban, Nawaf; Al-Otaibi, Hanan; Alayed, Abdulaziz; Alshankiti, Khaled; Al-Enizy, Mohammad A

2017-07-01

The aim of the study was to evaluate the influence of gender and skin color on the preference of different teeth shades in general population. Two standardized frontal smile photographs of male and female subjects were manipulated using photoshop to represent 4 skin colors [(type II, III, IV, and V) (Fitzpatrick scale)]. The teeth shades under each skin color were digitally manipulated to represent one of 6 teeth shades (BL1, BL2, BL3, BL4, B1 and A1). A questionnaire assessed demographic characteristics (age, nationality, gender, education level, occupation, and income) along with the satisfaction of their smiles. Male and female set of pictures with combination of skin colors and teeth shades were presented and participants were asked to select the most esthetically pleasing teeth shade with regard to gender and skin color. Cross-tabulations and chi-squared tests were used to perform the statistical analyses ( α  = 0.05). Three hundred and thirty-six (60.4% male; 39.6% female) individuals participated in the study. The difference in the preferred teeth shades was significant among the male and female photographs across all skin colors ( p  < 0.05). Lighter teeth shades were preferred among female subjects compared to male subjects with the same skin color. In addition, lighter teeth shades were preferred among subjects with a lighter skin color and vice versa ( p  < 0.05). Gender and skin color influences the perception of teeth shades among general population. Therefore, lighter tooth shades (BL1, BL2) for lighter skin color and comparatively darker tooth shades (BL4, B1, A1) for darker skin individuals should be prescribed as these are perceived as natural among Saudi population.

The effect of various disinfectants on dental shade guides.

PubMed

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

2014-09-01

Dental shade guides are used to evaluate tooth color before prosthodontic procedures and are subjected to disinfection after use. The effect of disinfection on shade guides has not been thoroughly investigated. The purpose of this study was to evaluate the effect of disinfectants on the color of shade tabs. Changes in the color (ΔE) of VITA Classical Shade Guide tabs were measured with a VITA Easyshade spectrophotometer in the CIELAB system and calculated after being subjected to Cavicide, Asepticare TB, Sporicidin, and distilled water (control) over a simulated period of 2 years. Statistical analysis was accomplished by a 2-way analysis of variance followed by the Tukey honestly significant difference (HSD) test (α=.05). A significant difference was noted in the degree of shade tab color change, depending on the type of disinfectant used (F=153.2, P<.001). No significant difference was noted in the amount of shade tab color change that occurred after disinfection among the different shade tabs used (F=0.611, P=.865), nor was a significant interaction noted between the type of disinfectant and the different shade tabs used (F=0.7, P=.919). Asepticare TB showed the least significant amount of change (ΔE=0.401), and Sporicidin (ΔE=0.889) and the control (ΔE=0.969) showed significantly more color change than Asepticare TB but less than Cavicide (ΔE=1.198). The average total CIELAB color difference for 50% human perceptibility is approximately 1 unit (under standardized laboratory conditions). In the oral cavity, however, an average change of 3.7 ΔE units could still allow teeth to be perceived as having the same color. Therefore, although the results are statistically significant, they may not be clinically important. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

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

PubMed

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

2018-05-16

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

Evaluating the accuracy of tooth color measurement by combining the Munsell color system and dental colorimeter.

PubMed

Chang, Jiun-Yao; Chen, Wen-Cheng; Huang, Ta-Ko; Wang, Jen-Chyan; Fu, Po-Sung; Chen, Jeng-Huey; Hung, Chun-Cheng

2012-09-01

As we pay increasing attention to dental aesthetics, tooth color matching has become an important part of daily dental practice. This aim of this study was to develop a method to enhance the accuracy of a tooth color matching machine. The Munsell color tabs in the range of natural human teeth were measured using a tooth color measuring machine (ShadeEye NCC). The machine's accuracy was analyzed using an analysis of variance test and a Tukey post-hoc test. When matching the Munsell color tabs with the ShadeEye NCC colorimeter, settings of Chroma greater than 6 and Value less than 4 showed unacceptable clinical results. When the CIELAB mode was used, the a* value (which represents the red-green axis in the Commission Internationale de l'Eclairage color space) made no significant difference (p=0.84), the L* value (which represents the lightness) resulted in a negative correlation, and the b* value (which represents the yellow-blue axis) resulted in a positive correlation with ΔE. When the Munsell color tabs and the Vitapan were measured in the same mode and compared, the inaccuracies showed that the Vitapan was not a proper tool for evaluating the stability and accuracy of ShadeEye NCC. By knowing the limitations of the machine, we evaluated the data using the Munsell color tabs; shade beyond the acceptable range should be reevaluated using a visual shade matching method, or if measured by another machine, this shade range should be covered to obtain more accurate results. Copyright © 2012. Published by Elsevier B.V.

Evaluating the ability of dental technician students and graduate dentists to match tooth color.

PubMed

Sinmazisik, Gulden; Trakyali, Goksu; Tarcin, Bilge

2014-12-01

The ability of dental technician students to match tooth shade with the Vita 3D-Master shade guide and Toothguide Training Box has not been investigated. The purpose of this study was to evaluate and compare the shade-matching ability of dental technician students and graduate dentists using the Vita 3D-Master shade guide. Twenty-nine dental technician students (DTS group) and 30 graduate dentists (GD group) participated in this study. The Toothguide Training Box (TTB) was used to train the participants and test their shade-matching abilities. Shade-matching ability was evaluated with 3 exercises and a final test, all of which are components of the TTB. The number of mistakes for each participant for value (L), chroma (c), and hue (h) were recorded during the exercises and the final test, and the mistake ratios were calculated. Color difference (ΔE) values for each shade were calculated from the L*, a*, and b* values of the Vita 3D-Master shade guide for each participant in both groups. The Mann-Whitney U test was used to determine statistically significant differences between the L, c, and h mistake ratios of the 2 groups, and the Student t test was used to determine statistically significant differences between the final test scores and the ΔE values of the groups (α=.05). The mistake ratio for L in the GD group was significantly higher than that of the DTS group (P<.05), whereas the mistake ratio for h in the DTS group was higher (P<.001). No significant differences were observed between the groups regarding the mistake ratios for c (P>.05). With regard to the final test scores and the ΔE values, no significant differences were found between the groups (P<.001), and the DTS group received higher scores than the GD group (912 and 851). The mean ΔE values for the DTS and GD groups were 1.72 and 2.92. DTSs made more mistakes in the h parameter than GDs, and GDs made more mistakes in the L parameter than DTSs. With regard to the final test scores and the ΔE values, DTSs were more successful in shade matching than GDs. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Translucency changes of direct esthetic restorative materials after curing, aging and treatment

PubMed Central

2016-01-01

The purpose of this article was to review the changes in translucency of direct esthetic restorative materials after curing, aging and treatment. As a criterion for the evaluation of clinical translucency changes, visual perceptibility threshold in translucency parameter difference (ΔTP) of 2 was used. Translucency changes after curing were perceivable depending on experimental methods and products (largest ΔTP in resin composites = 15.9). Translucency changes after aging were reported as either relatively stable or showed perceivable changes by aging protocols (largest ΔTP in resin composites = -3.8). Translucency changes after curing, aging and treatment were perceivable in several products and experimental methods. Therefore, shade matching of direct esthetic materials should be performed considering these instabilities of translucency in direct esthetic materials. PMID:27847744

Patterns of shading tolerance determined from experimental light reduction studies of seagrasses

EPA Science Inventory

An extensive review of the experimental literature on seagrass shading evaluated the relationship between experimental light reductions, duration of experiment and seagrass response metrics to determine whether there were consistent statistical patterns. There were highly signif...

Evaluating Accuracy of the Sunnova Pro Platform Shade Measurement

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

Self-shading associated with a skylight-blocked approach system for the measurement of water-leaving radiance and its correction.

PubMed

Shang, Zhehai; Lee, Zhongping; Dong, Qiang; Wei, Jianwei

2017-09-01

Self-shading associated with a skylight-blocked approach (SBA) system for the measurement of water-leaving radiance (L w ) and its correction [Appl. Opt.52, 1693 (2013)APOPAI0003-693510.1364/AO.52.001693] is characterized by Monte Carlo simulations, and it is found that this error is in a range of ∼1%-20% under most water properties and solar positions. A model for estimating this shading error is further developed, and eventually a scheme to correct this error based on the shaded measurements is proposed and evaluated. It is found that the shade-corrected value in the visible domain is within 3% of the true value, which thus indicates that we can obtain not only high precision but also high accuracy L w in the field with the SBA scheme.

Influence of Different Enamel Shades and Thickness on Chroma and Value of Dentin Vita Shade: An in vitro Comparative Assessment Study.

PubMed

Hajira, Noor Saira Wajid Najma; Mehta, Deepak; Ashwini, P; Meena, N; Usha, H L

2015-04-01

The aim of the present study is to determine the influence of different enamel shades of various thickness on chroma and value of vita shade of dentin. Three enamel composite resin shades (Enamel white, grey and neutral) and one dentin shade (A 2) from A melogen Plus (Ultradent) was used. Ninety Enamel disk specimens of 0.5, 0.75 and 1 mm thickness and 10 mm in diameter for each shade and 90 dentin disk specimens of 2 mm in thickness and 10 mm in diameter was used for the study. The spectrophotometric values of the dentin shade with and without enamel specimens were recorded and the values were converted to CIEL*a*b values. Statistical analysis was done using Pearson correlation coefficients to verify the effect of thickness on Chroma and value, and the significance was evaluated by one-way ANOVA and Tukey post hoc test. Two way ANOVA and Tukey post hoc was done to verify the variation within the groups. Results revealed a significant positive correlation between thickness and chroma and a negative correlation between thickness and value. There was a statistically significant variation in between the groups. All groups produced a significant increase in chroma with increase in thickness of enamel shade upto a thickness of 0.75 mm after which the behavior of each shade was erratic. Hence, the optimum thickness would be 0.75 mm. All groups produced a significant decrease in value with increase in thickness of enamel shade. Enamel white produced the greatest reduction in value, enamel neutral the least and enamel grey demonstrated an intermediate result. There is a need to have a knowledge of the effect on chroma and value when dentin is layered with different enamel shades, it is also important to understand the effect of these enamel shades at different thicknesses to better control the color and reproduce esthetic simulating natural teeth.

Using Cross-Polarized Photography as a Guide for Selecting Resin Composite Shade.

PubMed

Villavicencio-Espinoza, C A; Narimatsu, M H; Furuse, A Y

The restoration of single discolored maxillary anterior teeth is still a difficult task, as not only shape and surface characterization play an important role in the success of the treatment, but the propagation of light throughout the restorative material does as well. In some cases, small changes in morphology, color, and brightness will be noticeable. These factors are sometimes very tricky, and shade guides alone are difficult to use for color selection. This article proposes a protocol of employing cross-polarization imaging for improving the accuracy of the shade selection of resin composites. The step-by-step technique is presented for the restoration of a single discolored tooth.

Shade matching assisted by digital photography and computer software.

PubMed

Schropp, Lars

2009-04-01

To evaluate the efficacy of digital photographs and graphic computer software for color matching compared to conventional visual matching. The shade of a tab from a shade guide (Vita 3D-Master Guide) placed in a phantom head was matched to a second guide of the same type by nine observers. This was done for twelve selected shade tabs (tests). The shade-matching procedure was performed visually in a simulated clinic environment and with digital photographs, and the time spent for both procedures was recorded. An alternative arrangement of the shade tabs was used in the digital photographs. In addition, a graphic software program was used for color analysis. Hue, chroma, and lightness values of the test tab and all tabs of the second guide were derived from the digital photographs. According to the CIE L*C*h* color system, the color differences between the test tab and tabs of the second guide were calculated. The shade guide tab that deviated least from the test tab was determined to be the match. Shade matching performance by means of graphic software was compared with the two visual methods and tested by Chi-square tests (alpha= 0.05). Eight of twelve test tabs (67%) were matched correctly by the computer software method. This was significantly better (p < 0.02) than the performance of the visual shade matching methods conducted in the simulated clinic (32% correct match) and with photographs (28% correct match). No correlation between time consumption for the visual shade matching methods and frequency of correct match was observed. Shade matching assisted by digital photographs and computer software was significantly more reliable than by conventional visual methods.

Spectrophotometric and computerized evaluation of tooth bleaching employing 10 different home-bleaching procedures: In-vitro study

PubMed Central

Peskersoy, Cem; Tetik, Ayhan; Ozturk, Veli Ozgen; Gokay, Necmi

2014-01-01

Objective: The aim of this in-vitro study was to evaluate the efficacy of bleaching products, determine the applicability and validation of the measurement methods. Materials and Methods: Freshly extracted 110 human incisor teeth were stained with whole blood and hemolysate solution prior to the application of 10 different home-bleaching products. Spectrophotometric measurements of the tooth shades were performed for each specimen before and after bleaching at the 1st, 3rd, 7th, and 14 days. Differences in lightness (Δl), chroma (Δc), hue (Δh) values and shade changes were measured to evaluate process. Computerized digital imaging analyses to determine the color changes were performed with Photoshop CS4 software (Adobe, San Jose, CA, USA). Statistical analyses were performed with analysis of variance, Scheffe and Tukey tests. Results: In all of the test groups regardless of the material used, a significant increase in lightness and hue, and decrease of chroma were observed, as compared to the control group. After recommended bleaching applications, Δl and Δh values respectively increased in group Zaris White and Brite (ZWB) and group Pola Night and Δc values showed significant decrease in groups ZWB and Rembrandt REM3 (P < 0.05). At the end of the procedure both spectrophotometric and digital imaging analysis showed ZWB was the most effective product among the others while Yotuel and Happy Smile were the least (P < 0.05). Conclusions: Home-bleaching systems showed slower but almost permanent bleaching effect likewise office-based methods. Both software and spectrophotometric analyses have advantages such as evaluating the results objectively and numerically, also treatment outcomes could be preserved. PMID:25512738

Optical properties of base dentin ceramics for all-ceramic restorations.

PubMed

Shiraishi, Takanobu; Wood, Duncan J; Shinozaki, Nobuya; van Noort, Richard

2011-02-01

The study was conducted to compare the optical parameters of VM7(®) M-shade base dentin ceramics (VITA, Germany) for all ceramic restorations to the chemical composition across the 3D-MASTER(®) shade system. Three disc samples, 13 mm diameter and 1.4 mm thickness, were produced for each M-shade following the manufacturer's instructions. Each disc was ground and polished to a thickness of 1.0 mm. Spectral light transmittance and reflectance data were recorded in the visible spectrum under the standard illuminant D65 and 2° observer at 10 nm intervals by using a computer-controlled spectrophotometer. Opacity, translucency and opalescence parameters were determined for each sample. (1) Spectral transmittance and reflectance in the short-wavelength range systematically decreased with increasing chroma number (M1, M2, M3) when compared within the same value (lightness) group. (2) Spectral transmittance and reflectance decreased systematically across the whole visible spectrum with increasing value group number when compared within the same chroma group. (3) Analysis of relationship between chemical composition and various optical parameters for all the samples showed the significant contribution of ZrO₂ and Y₂O₃ substances to optical properties of the present material. Systematic variations in optical properties of VM7(®) M-shade base dentin ceramics were observed throughout the 3D-MASTER(®) shade system and were suggested to be caused by the fine structure of the sample which can interfere with shorter wavelengths in the visible spectrum. Copyright © 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Influence of abutment material and luting cements color on the final color of all ceramics.

PubMed

Dede, Dogu Ömür; Armaganci, Arzu; Ceylan, Gözlem; Cankaya, Soner; Celik, Ersan

2013-11-01

The purpose of this study is to evaluate the effects of different abutment materials and luting cements color on the final color of implant-supported all-ceramic restorations. Ten A2 shade IPS e.max Press disc shape all-ceramic specimens were prepared (11 × 1.5 mm). Three different shades (translucent, universal and white opaque) of disc shape luting cement specimens were prepared (11 × 0.2 mm). Three different (zirconium, gold-palladium and titanium) implant abutments and one composite resin disc shape background specimen were prepared at 11 mm diameter and appropriate thicknesses. All ceramic specimens colors were measured with each background and luting cement samples on a teflon mold. A digital spectrophotometer used for measurements and data recorded as CIE L*a*b* color co-ordinates. An optical fluid applied on to the samples to provide a good optical connection and measurements on the composite resin background was saved as the control group. ΔE values were calculated from the ΔL, Δa and Δb values between control and test groups and data were analyzed with one-way variance analysis (ANOVA) and mean values were compared by the Tukey HSD test (α = 0.05). One-way ANOVA of ΔL, Δa, Δb and ΔE values of control and test groups revealed significant differences for backgrounds and seldom for cement color groups (p the 0.05). Only zirconium implant abutment groups and gold palladium abutment with universal shade cement group were found to be clinically acceptable (ΔE ≤ 3.0). Using titanium or gold-palladium abutments for implant supported all ceramics will be esthetically questionable and white opaque cement will be helpful to mask the dark color of titanium abutment.

Color stability of shade guides after autoclave sterilization.

PubMed

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

2014-01-01

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

Modeling shade tree use by beef cattle as a function of black globe temperature and time of day

NASA Astrophysics Data System (ADS)

Foust, Amanda M.; Headlee, William L.

2017-12-01

Increasing temperatures associated with global climate change threaten to disrupt agricultural systems such as beef production, yet relatively little is known about the use of natural tree shade to mitigate the negative effects of heat stress on beef cattle. In this study, we evaluated how temperature and time of day influenced the utilization of tree shade in relation to coloration, orientation, and behavior of beef cattle in a pasture system. Temperatures in shade and direct sunlight were measured using black globe temperature (BGT) data loggers. Time-lapse images from game cameras were used to obtain counts of shade usage, coloration, orientation, and behavior of cattle throughout the daytime hours. In general, we found that shade utilization and most of the predominating orientations and behaviors differed significantly ( P < 0.05) by both time of day (Hour) and BGT in direct sunlight (BGTsun), while interactions between these two effects (Hour × BGTsun) were often nonsignificant. The mean percentage of the herd using shade was highest in mid-morning (87-96%) and early afternoon (97%), but also increased with BGTsun regardless of the time of day; these trends were similar for both dark- and light-colored cattle. Lying down was the dominant behavior exhibited in the shade, while foraging was the most prevalent behavior in the sun. When herd shade usage was lowest in mid- to late-afternoon (<1%) we also observed an increase in the use of heat-mitigating orientations in the sun (37-47%). We discuss some practical implications of these results, including the potential use of temperature thresholds to interpret cattle behaviors and shade usage.

Modeling shade tree use by beef cattle as a function of black globe temperature and time of day.

PubMed

Foust, Amanda M; Headlee, William L

2017-12-01

Increasing temperatures associated with global climate change threaten to disrupt agricultural systems such as beef production, yet relatively little is known about the use of natural tree shade to mitigate the negative effects of heat stress on beef cattle. In this study, we evaluated how temperature and time of day influenced the utilization of tree shade in relation to coloration, orientation, and behavior of beef cattle in a pasture system. Temperatures in shade and direct sunlight were measured using black globe temperature (BGT) data loggers. Time-lapse images from game cameras were used to obtain counts of shade usage, coloration, orientation, and behavior of cattle throughout the daytime hours. In general, we found that shade utilization and most of the predominating orientations and behaviors differed significantly (P < 0.05) by both time of day (Hour) and BGT in direct sunlight (BGT sun ), while interactions between these two effects (Hour × BGT sun ) were often nonsignificant. The mean percentage of the herd using shade was highest in mid-morning (87-96%) and early afternoon (97%), but also increased with BGT sun regardless of the time of day; these trends were similar for both dark- and light-colored cattle. Lying down was the dominant behavior exhibited in the shade, while foraging was the most prevalent behavior in the sun. When herd shade usage was lowest in mid- to late-afternoon (<1%) we also observed an increase in the use of heat-mitigating orientations in the sun (37-47%). We discuss some practical implications of these results, including the potential use of temperature thresholds to interpret cattle behaviors and shade usage.

Colour parameters and shade correspondence of CAD-CAM ceramic systems.

PubMed

Della Bona, Alvaro; Pecho, Oscar E; Ghinea, Razvan; Cardona, Juan C; Pérez, María M

2015-06-01

To evaluate colour differences between (1) CAD-CAM ceramic systems considering shades A1, A2 and A3 and the corresponding nominal shade of VC (Vita Classical shade guide) and (2) shades A1-A2, A2-A3 and A1, A2 and A3 within the same ceramic system. Samples of shades A1, A2 and A3 were fabricated (n=5) from CAD-CAM ceramic blocks (IPS e.max(®) CAD LT and HT, IPS Empress(®) CAD LT and HT, Paradigm™ C, and VITABLOCS(®) Mark II) and polished to 1.0±0.01mm in thickness. Spectral reflectance and colour coordinates were measured using a spectroradiometer inside a viewing booth using the CIE D65 illuminant and the d/0° geometry. Spectral reflectance curves were compared using VAF coefficient and were statistically analyzed using Kruskal-Wallis and the Mann-Whitney U test (α=0.05). Colour coordinates were statistically analyzed using one-way ANOVA, Tukey's test with Bonferroni correction (α=0.001). All colour differences (ΔEab(*) and ΔE00) were analyzed through comparisons with the PT - perceptibility and AT - acceptability thresholds for dental ceramics. ΔE between ceramic systems and its corresponding shade ranged from 6.32 to 13.42 (ΔEab(*)) and 4.48 to 9.30 (ΔE00). ΔE between shades A1-A2, A2-A3 and A1, A2 and A3 ranged, respectively, 1.93-4.82, 1.22-5.59 and 3.63-8.84 (ΔEab(*)); 1.54-3.87, 1.03-3.90 and 2.95-6.51 (ΔE00). Considering the corresponding nominal shade from VC, none of the ceramic systems showed colour differences below the AT. In addition, some ceramic systems showed colour differences below AT (shades A1-A2 and A2-A3) and below PT (shades A2-A3). Careful adjustments should be made to the final shade of CAD-CAM ceramic restorations to reach a clinically acceptable shade match. Copyright © 2015 Elsevier Ltd. All rights reserved.

[Effects of shading on endogenous hormones regulation in kernel development of summer maize in the field].

PubMed

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

2014-05-01

Taking 3 maize hybrids, Zhenjie 2 (ZJ2), Denghai 605 (DH605) and Zhengdan 958 (ZD958) as test materials, the effects of shading on the physiological function of endogenous hormones during grain formation of summer maize were investigated in the field. The ambient sunshine treatment was used as the control (CK) and 3 shading treatments with a shading degree of 60% were designed in growth periods ranging from tasseling to maturity (S1), from jointing to tasseling stage (S2) and whole growing period (S3), respectively. Results showed that the total floret number, filament number and pollination floret number decreased after shading in comparison with CK, and aborted seeds increased accordingly. The kernels per ear showed an order of CK > S2 > S > S3, and those of S1, S2 and S3 were 18.9%, 43.7% and 80.8% lower than that of CK. The IAA, GA and ZR contents of normal grain in the shading treatments were lower than in CK, while the ABA content was opposite. The same hormone change with grain growth in all treatments presented a similar trend. Compared to normal grains, the maximum value of IAA content in aborted grains shifted from the 20th day to the 10th day after pollination, with less IAA accumulation and rapid reduction, and the contents of GA and ZR decreased significantly, while that of ABA was still high at the 20th day after pollination. Therefore, the effects of shading on hormone contents in grains might lead to grain abortion and yield reduction.

[Measurement of chromaticity of five hued zirconia].

PubMed

Wen, Ning; Shao, Long-quan; Yi, Yuan-fu; Deng, Bin; Liu, Hong-chen

2009-05-01

To determine the chroma value of sintered IL1-IL5 zirconia materials in comparison with the Vita In-Ceram YZ color shade. Five types of shading dental zirconia ceramics with color gradient were prepared by adding Fe2O3, CeO2, and Bi2O3 to the zirconia powder, and their chroma values were determined using a spectrophotometer and the color difference was calculated. The chroma value ranges were L: 67.76-77.78, a: -2.19-3.80, and b: 12.13-25.01. Slight deltaE was found between IL1 and LL1, IL2 and LL2, and IL3 and LL3. The deltaE between IL4 and LL4 could be compensated by veneering porcelain, whereas deltaL between IL5 and LL5 could not be compensated in this manner. Shading dental zirconia ceramics can be prepared by addition of metal oxides with color similar to the Vita In-Ceram YZ color shades to match that of the veneering porcelain in clinical practice.

The effect of enamel porcelain thickness on color and the ability of a shade guide to prescribe chroma.

PubMed

Jarad, F D; Moss, B W; Youngson, C C; Russell, M D

2007-04-01

To test the null hypothesis that there is no color change when enamel porcelain thickness is changed and to evaluate the ability of a shade guide to prescribe chroma. Three shades (3M1, 3M2 and 3M3) were selected from a Vitapan 3D master shade guide. Five disk specimens were prepared for each shade, consisting of three layers (opacious dentin, dentin and enamel) at thicknesses of 0.6, 0.8 and 0.6mm, respectively. The color of each disk was measured using a spectrophotometer. Enamel porcelain was reduced in thickness to 0.3mm and porcelain disks were remeasured. Reducing the enamel thickness of porcelain disk specimens significantly increased L) (p<0.05), b*, metric chroma and hue angle (p<0.001). For the three shades studied (3M1, 3M2 and 3M3) L* values were not significantly different (p>0.05) and chroma increased for 3M1 with the lowest chroma to 3M3 with the highest chroma, which is in line with the shade guide specifications. Although statistically significant (p<0.001) changes in hue angle between the three shades were small (less than 3 degrees overall). The difference in chroma between the three shades 3M1, 3M2 and 3M3 was greatest for the thin enamel layer than the thick enamel layer. A change in enamel thickness from 0.6 to 0.3mm resulted in a three-unit change in L* and metric chroma and a 4 degrees change in hue angle. A change in enamel porcelain thickness will have a greater effect on higher chromatic shades than those with lower chroma. The ability of the shade guide to prescribe chroma was demonstrated but this could be offset by an anomalous enamel thickness.

A new methodology for fluorescence analysis of composite resins used in anterior direct restorations.

PubMed

de Lima, Liliane Motta; Abreu, Jessica Dantas; Cohen-Carneiro, Flavia; Regalado, Diego Ferreira; Pontes, Danielson Guedes

2015-01-01

The aim of this study was to use a new methodology to evaluate the fluorescence of composite resins for direct restorations. Microhybrid (group 1, Amelogen; group 2, Opallis; group 3, Filtek Z250) and nanohybrid (group 4, Filtek Z350 XT; group 5, Brilliant NG; group 6, Evolu-X) composite resins were analyzed in this study. A prefabricated matrix was used to prepare 60 specimens of 7.0 × 3.0 mm (n = 10 per group); the composite resin discs were prepared in 2 increments (1.5 mm each) and photocured for 20 seconds. To establish a control group of natural teeth, 10 maxillary central incisor crowns were horizontally sectioned to create 10 discs of dentin and enamel tissues with the same dimensions as the composite resin specimens. The specimens were placed in a box with ultraviolet light, and photographs were taken. Aperture 3.0 software was used to quantify the central portion of the image of each specimen in shades of red (R), green (G), and blue (B) of the RGB color space. The brighter the B shade in the evaluated area of the image, the greater the fluorescence shown by the specimen. One-way analysis of variance revealed significant differences between the groups. The fluorescence achieved in group 1 was statistically similar to that of the control group and significantly different from those of the other groups (Bonferroni test). Groups 3 and 4 had the lowest fluorescence values, which were significantly different from those of the other groups. According to the results of this study, neither the size nor the amount of inorganic particles in the evaluated composite resin materials predicts if the material will exhibit good fluorescence.

Application of a digital technique in evaluating the reliability of shade guides.

PubMed

Cal, E; Sonugelen, M; Guneri, P; Kesercioglu, A; Kose, T

2004-05-01

There appears to be a need for a reliable method for quantification of tooth colour and analysis of shade. Therefore, the primary objective of this study was to show the applicability of graphic software in colour analysis and secondly to investigate the reliability of commercial shade guides produced by the same manufacturer, using this digital technique. After confirming the reliability and reproducibility of the digital method by using self-assessed coloured images, three shade guides of the same manufacturer were photographed in daylight and in studio environments with a digital camera and saved in tagged image file format (TIFF) format. Colour analysis of each photograph was performed using the Adobe Photoshop 4.0 graphic program. Luminosity, and red, green, blue (L and RGB) values of each shade tab of each shade guide were measured and the data were subjected to statistical analysis using the repeated measure Anova test. The L and RGB values of the images taken in daylight differed significantly from those of the images taken in studio environment (P < 0.05). In both environments, the luminosity and red values of the shade tabs were significantly different from each other (P < 0.05). It was concluded that, when the environmental conditions were kept constant, the Adobe Photoshop 4.0 colour analysis program could be used to analyse the colour of images. On the other hand, the results revealed that the accuracy of shade tabs widely being used in colour matching should be readdressed.

Effect of altitude on biochemical composition and quality of green arabica coffee beans can be affected by shade and postharvest processing method.

PubMed

Worku, Mohammed; de Meulenaer, Bruno; Duchateau, Luc; Boeckx, Pascal

2018-03-01

Although various studies have assessed altitude, shade and postharvest processing effects on biochemical content and quality of coffee beans, data on their interactions are scarce. The individual and interactive effects of these factors on the caffeine, chlorogenic acids (CGA) and sucrose contents as well as physical and sensory qualities of green coffee beans from large plantations in southwestern Ethiopia were evaluated. Caffeine and CGA contents decreased with increasing altitude; they respectively declined 0.12 and 1.23gkg -1 100m -1 . Sucrose content increased with altitude; however, the altitude effect was significant for wet-processed beans (3.02gkg -1 100m -1 ), but not for dry-processed beans (0.36g kg -1 100m -1 ). Similarly, sucrose content increased with altitude with much stronger effect for coffee grown without shade (2.11gkg -1 100m -1 ) compared to coffee grown under shade (0.93gkg -1 100m -1 ). Acidity increased with altitude when coffee was grown under shade (0.22 points 100m -1 ), but no significant altitude effect was observed on coffee grown without shade. Beans grown without shade showed a higher physical quality score for dry (37.2) than for wet processing (29.1). These results generally underline the complex interaction effects between altitude and shade or postharvest processing on biochemical composition and quality of green arabica coffee beans. Copyright © 2017. Published by Elsevier Ltd.

[The use of computer-aided colorimeter in porcelain-fused-to-metal (PFM) crowns among patients with special colored teeth].

PubMed

Fu, Yuan-fei; Weng, Wei-min

2004-02-01

To evaluate the roll of ShadeEye-NCC, a computer-aided colorimeter, in Porcelain-Fused-to-Metal crowns among patients with special colored Teeth. The first step was to choose the proper patients. The next was to use the colorimeter to measure the base shade of tooth and fabricate the PFM crowns according to the recipe given by the colorimeter. At last, the effects of the PFM crowns were evaluated subjectively by patients and doctor. The satisfaction rates of patients and doctor were 83.7% and 81.4% respectively, there was no significant difference between the two rates. The computer-aided colorimeter can offer good base shade recipe for fabricating PFM crowns of patients with special colored teeth.

Masking properties of ceramics for veneer restorations.

PubMed

Skyllouriotis, Andreas L; Yamamoto, Hideo L; Nathanson, Dan

2017-10-01

The translucency and opacity of ceramics play a significant role in emulating the natural color of teeth, but studies of the masking properties and limitations of dental ceramics when used as monolayer restorations are lacking. The purpose of this in vitro study was to determine the translucency of 6 materials used for veneer restorations by assessing their translucency parameters (TPs), contrast ratios (CRs), and potential to mask dark tooth colors. Ten square- or disk-shaped specimens (0.5-mm thickness, shade A2) were fabricated from Vitablocks Mark II (VMII; Vita Zahnfabrik), IPS e.max CAD LT (EMXC LT; Ivoclar Vivadent AG), IPS e.max CAD HT (EMXC HT; Ivoclar Vivadent AG), IPS Empress CAD LT (EMP LT; Ivoclar Vivadent AG), IPS e.max Press LT (EMXP LT; Ivoclar Vivadent AG), and CZR (CZR; Kuraray Noritake Dental Inc). Their luminance (Y) values over black and over white tiles were measured, followed by their color (CIELab) over black tiles and white tiles and shaded A2 (control group), A3.5, A4, and B4 acrylic resin blocks. All measurements were performed using a spectrophotometer in 2 different areas on each specimen. Then CRs, TPs, and color differences (over shaded backgrounds) were determined. Data were subjected to 1-way and 2-way ANOVA (α=.05) for analysis. Mean CR values of EMXP LT were significantly higher than those of the other tested materials, whereas VMII and EMXC HT had the lowest values (P<.001). Mean TP values over black and over white backgrounds of VMII and EMXC HT were significantly higher than those of the other tested materials, while EMXP LT and EMXC LT revealed the lowest values (P<.001). Background shade A4 displayed the highest mean effect (expressed in ΔE* values) on the color of the ceramic materials, whereas shade B4 demonstrated the lowest mean background effect (P<.001). Significant differences in translucency among the tested ceramics were revealed (P<.001). The EMXC LT and EMXP LT groups were the least translucent under the conditions of this study (P<.001). All tested ceramics exhibited poor masking properties against the A4 background. The color differences of most tested ceramics were more acceptable when tested against the B4 background (ΔE*≤3.3). Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Rheological properties of veneer trial pastes relevant to clinical success.

PubMed

Chadwick, R G; McCabe, J F; Carrick, T E

2008-03-22

The porcelain veneer is a relatively conservative means of improving the appearance of teeth. As these restorations are usually highly visible it is essential to gain the approval of the patient before final cementation takes place. As a result a variety of trial pastes are available that match the shades of the resins that are used ultimately to finally cement the veneer in place. Such restorations, by virtue of their small size and fragility, are difficult to handle and position. It is therefore important that the application of trial paste does not impede placement and retention upon the tooth surface at try in whilst the patient assesses its appearance. To determine the rheological properties of three makes of trial pastes (Calibra - Dentsply Caulk, USA; Nexus - Kerr, USA; Rely X - 3M Espe, USA) and assess if temperature affected these. Design In vitro rheological measurement. For each product the rheological properties of three shades were determined at both 25 degrees C and 35 degrees C three times. Measurements of both the Initial Yield Stress and Shear Rate Index were undertaken using a controlled stress rheometer (Carri-med, Dorking, UK) in flow mode with a cone-and-plate test configuration. One way analyses of variance of the initial yield and shear rate index for each shade of material at 25 and 35 degrees C demonstrated no significant effects of temperature with the exception of the initial yield of Nexus (P = 0.0024) where the yield stress of the white shade was significantly (P <0.01) higher at 35 degrees C than at 25 degrees C. In all cases the yield stress for Nexus was of the order of ten times higher than the other materials. All materials demonstrated pseudoplastic behaviour. The variation in yield stress displayed by the materials will affect the handling of veneers and offers a potentially useful choice parameter to the clinician as to which paste bests suits their requirements.

[Chromatic study of all-ceramic restorations--influence of abutment tooth color on color tone of copings].

PubMed

Hata, Utako; Yamamura, Osamu; Kawauchi, Daisuke; Fujii, Teruhisa

2006-01-01

Recently, the use of all-ceramic crowns has spread widely in clinical applications to meet the demand for both functional and esthetically-pleasing restorations. In making all-ceramic crowns, it is necessary to reproduce the shape and color near to those of the natural teeth. However, the color shades of abutments might influence the color of the copings which are made of material with high transparency. This study examined the influence of the color shades of the abutments on the final color of copings for three kinds of all-ceramic core materials: Empress, Empress 2 (IVOCLAR VIVADENT), and Procera AllCeram (Nobel Biocare). Copings with 0.5 mm in thickness were fabricated by using Empress (TC1), Empress 2 (100), and Procera AllCeram (white) core materials for an upper-right central incisor. Abutments were made by using six kinds of die materials of the Empress system (ST1, ST2, ST3, ST5, ST8, ST9), gold-silver-palladium alloy, gold alloy, and experimental black body. Copings were inserted in each abutment and the final color of the central part of the buccal surface was measured using a spectrophotometer according to the L*a*b* color system. Regardless of the color shades of the abutments, the chroma values of the copings rose in the order of Empress, Empress 2, and Procera, and the values of lightness rose in the order of Empress, Procera, and Empress 2. When the final color of each coping measured under the wet and dry conditions were compared, the difference in chroma was great. Within the limitations of this study, the results suggest that the influence of the color shades of the abutments on the final color of the three kinds of copings is small in the order of Empress, Procera, and Empress 2. In clinical and dental laboratory operations, it is hoped to observe and measure the color of copings and restorations under the wet condition.

The effect of chemical disinfectants on the color of a porcelain shade guide.

PubMed

ArRejaie, Aws S

2014-07-01

To evaluate the effect of long term utilization of chemical disinfectants on the color of porcelain shade guides. three chemical disinfectants were used in this study: Minuten spray, Lysol ICQuaternary Disinfectant Cleaner (QDC), and Lysol IC Ready to Use Disinfectant Cleaner (RDC). Simulation of disinfecting cycles for one year, two years, and three years were done on Vita 3D master shade guide. Color differences were determined by visual inspection and analyzing ΔE. ΔE values were significantly below the perceptible (ΔE=1) and the clinically acceptable (ΔE=3.7) thresholds. Simulated utilization of Minuten Spray, Lysol IC (QDC), and Lysol (RDC) disinfectants for up to three years didn't cause a clinically significant difference in the color of VITA Toothguide 3D-Master Shade Guide.

Conservative restoration of a traumatically involved central incisor.

PubMed

Bassett, Joyce

2012-04-01

The use of a direct composite material known for excellent polishability, polish retention, and wear resistance is described in this case of a fractured central incisor restoration. The method used enabled the clinician to conserve tooth structure and maintain full control of the outcome while creating an esthetically imperceptible, reliable, and durable restoration for a young male patient. Emphasized in this case are the techniques of layering, contouring, and polishing of a nanocomposite used to maximize esthetics and meet patient expectations. To further ensure imperceptibility, the author recommends first facilitating color shade selection for both body and dentin-especially in two-shade or multiple-shade restorations-by placing the composite in its planned area of the restoration and curing it in its proper thickness to allow a preview and recipe map.

Analysis of Shade Matching in Natural Dentitions Using Intraoral Digital Spectrophotometer in LED and Filtered LED Light Sources.

PubMed

Chitrarsu, Vijai Krishnan; Chidambaranathan, Ahila Singaravel; Balasubramaniam, Muthukumar

2017-10-31

To evaluate the shade matching capabilities in natural dentitions using Vita Toothguide 3D-Master and an intraoral digital spectrophotometer (Vita Easyshade Advance 4.0) in various light sources. Participants between 20 and 40 years old with natural, unrestored right maxillary central incisors, no history of bleaching, orthodontic treatment, or malocclusion and no rotations were included. According to their shades, subjects were randomly selected and grouped into A1, A2, and A3. A total of 100 participants (50 male and 50 female) in each group were chosen for this study. Shade selection was made between 10 am and 2 pm for all light sources. The same examiner selected the shade of natural teeth with Vita Toothguide 3D-Master under natural light within 2 minutes. Once the Vita Toothguide 3D-Masterwas matched with the maxillary right central incisor, the L*, a*, and b* values, chroma, and hue were recorded with Vita Easyshade Advance 4.0 by placing it on the shade tab under the same light source. The values were statistically analyzed using one-way ANOVA and Tukey's HSD post hoc test with SPSS v22.0 software. The mean ∆E* ab values for shades A1, A2, and A3 for groups 1, 2, and 3 were statistically significantly different from each other (p < 0.001). The intraoral digital spectrophotometer showed statistically significant differences in shade matching compared to Vita Toothguide 3D-Master. Incandescent light showed more accurate shade matching than the filtered LED, LED, and daylight. © 2017 by the American College of Prosthodontists.

Comparison of Shade of Ceramic with Three Different Zirconia Substructures using Spectrophotometer.

PubMed

Habib, Syed Rashid; Shiddi, Ibraheem F Al

2015-02-01

This study assessed how changing the Zirconia (Zr) substructure affected the color samples after they have been overlaid by the same shade of veneering ceramic. Three commercial Zr materials were tested in this study: Prettau(®) Zirconia (ZirKonZahn, Italy), Cercon (Dentsply, Germany) and InCoris ZI (Sirona, Germany). For each system, 15 disk-shaped specimens (10 × 1 mm) were fabricated. Three shades of A1, A2 and A3.5 of porcelain (IPS e.MaxCeram, IvoclarVivadent, USA) were used for layering the specimens. Five specimens from each type of Zr were layered with same shade of ceramic. Color measurements were recorderd by a spectrophotometer Color-Eye(®) 7000A (X-Rite, Grand Rapids, MI). Mean values of L, a, b color coordinates and ΔE were recorded and comparisons were made. Differences in the ΔE were recorded for the same porcelain shade with different Zr substructures and affected the color of the specimens (p < 0.01, ANOVA). The maximum difference between the ΔE values for the A1, A2 and A3.5 shades with three types of Zr substructures was found to be 1.59, 1.69 and 1.45 respectively. Multiple comparisons of the ΔE with PostHoc Tukey test revealed a statistically significant difference (p < 0.05) between the three types of Zr, except between Type 2 Zr and Type 3 Zr for the Shade A1. The mean values of L, a, b and ΔE for the Prettau(®) Zirconia substructure were found to be the least among the three types. The brand of Zr used influences the final color of the all ceramic Zr based restorations and this has clinical significance.

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. Implications for future experimental studies are described, some of which are already being implemented in follow-on studies.

Improved tooth bleaching combining ozone and hydrogen peroxide--A blinded study.

PubMed

Al-Omiri, Mahmoud K; Abul Hassan, Ra'ed S; AlZarea, Bader K; Lynch, Edward

2016-03-01

To evaluate the efficacy of tooth bleaching using ozone after hydrogen peroxide (H2O2) in comparison to the use of H2O2 alone. 70 extracted teeth were randomly distributed into two groups. Teeth surfaces in group 1 (n=35) were treated using 38% H2O2 and then were exposed to ozone for 60s and this ozonated peroxide mixture was left on the teeth for 20 min. Meanwhile, teeth in group 2 (n=35) were treated with H2O2 38% for 20 min. The L* a* b* and Vita Classic shade values of teeth were evaluated in both groups at base line, after application of H2O2 and ozone in group 1, and after application of H2O2 and then again after another application of ozone in group 2. The statistically significant changes were set at P ≤ 0.05. Baseline L* a* b* and Vita shade values were comparable between groups (P>0.05). Teeth obtained lighter shades following bleaching with both H2O2 and ozone or with H2O2 alone (P ≤ 0.05). Further bleaching with ozone for teeth already bleached with H2O2 alone showed further improvement of the shades of teeth (P<0.001). Teeth treated with H2O2 and ozone had more shade improvements than those only treated with H2O2 (P<0.001). Also, L* values were increased while b* values were decreased (teeth obtained lighter shades) following bleaching in both groups (P ≤ 0.05). More changes were obtained when both ozone and H2O2 were used (P ≤ 0.05). Bleaching with 38% H2O2 and ozone resulted in teeth with lighter shades than bleaching with 38% H2O2 alone. Copyright © 2016 Elsevier Ltd. All rights reserved.

[Measurement and comparison of the spectral transmittance of cerinate porcelain and human enamel].

PubMed

Chen, Ji-Hua; Zhou, Guo-Feng; Wei, Zhang-Rui; Wang, Hui; Zhao, San-Jun

2006-12-01

To measure the spectral transmittance of Cerinate porcelain veneer and enamel in different color and different thickness. Samples of Cerinate porcelain veneers were prepared in different thickness (0.50 mm, 0.75 mm, 1.00 mm) and different Vita shade (A1, A2, A3). Enamel samples in shade A2 were made with three thickness (0.50 mm, 0.75 mm, 1.00 mm). A spectrophotometer with spectra range (380-800 nm) was employed to measure the spectral transmittance. Spectral transmittance decreased with the increasing in the thickness of specimens and decreasing in the color darkness. The transmittance of Cerinate porcelain veneer material and enamel in the same color and same thickness hadn't significant difference. The key factor to spectral transmittance of porcelain veneer materials is veneer's thickness, and the color of the materials has also some influence on it. Cerinate porcelain veneers can properly recover the transparency of teeth.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deline, Chris; Meydbray, Jenya; Donovan, Matt

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 ofmore » distributed PV power electronics. Also, due to the emergence of new technologies including sub-module embedded power electronics, the shading method has been extended to include power electronics that operate at a finer granularity than the module level. An update to the method is proposed to account for these emerging technologies that respond to shading differently than module-level devices. The partial shading test remains a repeatable test procedure that attempts to simulate shading situations as would be experienced by typical residential or commercial rooftop photovoltaic (PV) systems. Performance data for multiple products tested using this method are discussed, based on equipment from Enphase, Solar Edge, Maxim Integrated and SMA. In general, the annual recovery of shading losses from the module-level electronics evaluated is 25-35%, with the major difference between different trials being related to the number of parallel strings in the test installation rather than differences between the equipment tested. Appendix D data has been added in this update.« less

The IRGen infrared data base modeler

NASA Technical Reports Server (NTRS)

Bernstein, Uri

1993-01-01

IRGen is a modeling system which creates three-dimensional IR data bases for real-time simulation of thermal IR sensors. Starting from a visual data base, IRGen computes the temperature and radiance of every data base surface with a user-specified thermal environment. The predicted gray shade of each surface is then computed from the user specified sensor characteristics. IRGen is based on first-principles models of heat transport and heat flux sources, and it accurately simulates the variations of IR imagery with time of day and with changing environmental conditions. The starting point for creating an IRGen data base is a visual faceted data base, in which every facet has been labeled with a material code. This code is an index into a material data base which contains surface and bulk thermal properties for the material. IRGen uses the material properties to compute the surface temperature at the specified time of day. IRGen also supports image generator features such as texturing and smooth shading, which greatly enhance image realism.

The Effect of Chemical Disinfectants on the Color of a Porcelain Shade Guide

PubMed Central

ArRejaie, Aws S.

2014-01-01

Objective To evaluate the effect of long term utilization of chemical disinfectants on the color of porcelain shade guides. Methodology three chemical disinfectants were used in this study: Minuten spray, Lysol ICQuaternary Disinfectant Cleaner (QDC), and Lysol IC Ready to Use Disinfectant Cleaner (RDC). Simulation of disinfecting cycles for one year, two years, and three years were done on Vita 3D master shade guide. Color differences were determined by visual inspection and analyzing ΔE. Results ΔE values were significantly below the perceptible (ΔE=1) and the clinically acceptable (ΔE=3.7) thresholds. Conclusions Simulated utilization of Minuten Spray, Lysol IC (QDC), and Lysol (RDC) disinfectants for up to three years didn’t cause a clinically significant difference in the color of VITA Toothguide 3D-Master Shade Guide. PMID:25505865

Effects of shade on welfare and meat quality of grazing sheep under high ambient temperature.

PubMed

Liu, H W; Cao, Y; Zhou, D W

2012-12-01

This study was conducted to evaluate the effects of providing shade on growth performance, welfare, and meat quality of grazing sheep under high ambient temperature. A total of 120 healthy male Ujumqin wool sheep (a local breed; BW = 18.7 ± 1.27 kg; 14 wk old) were randomly and equally divided into shaded and unshaded treatments with 3 pens per treatment. Sheep were grazed on an unshaded pastureland from 0600 to 1000 h and 1400 to 1800 h. During other times, sheep were confined in shaded or unshaded pens. Body weight was recorded on d 1 and 42 of the experiment. Rectal temperature and respiration rate were recorded on d 7, 14, 21, 28, 35, and 42. At end of the trial, sheep were blood sampled and slaughtered to collect meat samples. Respiration rate was greater (P < 0.05) in the unshaded sheep than shaded sheep on d 14, 21, 28, 35, and 42 of the trial whereas no significant differences were found on d 7. Moreover, no differences were observed in final BW, ADG, or rectal temperature throughout the trial. The pH at 24 h postmortem (pH(24)) and cooking loss were greater (P < 0.01) in unshaded than shaded sheep. On the contrary, lightness (L*), redness (a*) and yellowness (b*) values at 24 h postmortem were lower (P < 0.05) in unshaded versus shaded sheep. The sheep in the unshaded group had a greater (P < 0.05) cortisol concentration compared with the shaded group. Sheep in the shaded group had lower creatine kinase activity (P < 0.01) as well as observed for glucose (P < 0.05), triiodothyronine (P < 0.01), and thyroxine (P < 0.05) concentrations and white blood cell count (P < 0.05). Compared with the unshaded group, sheep in the shaded group had a greater lymphocytes (LYM) count (P < 0.05). In contrast, the opposite was true for neutrophils (NEU) count (P < 0.01) and NEU:LYM ratio (P < 0.01). In conclusion, the shade cloth, although not enhancing ADG, improved meat quality traits and certain stress parameters in grazing sheep reared under high ambient temperature.

Clinical study of tooth shade lightening from dentist-supervised, patient-applied treatment with two 10% carbamide peroxide gels.

PubMed

Cibirka, R M; Myers, M; Downey, M C; Nelson, S K; Browning, W D; Hawkins, I K; Dickinson, G L

1999-01-01

Prescribed, patient-applied tooth lightening agents, or nightguard vital bleaching, typically utilizes a 10% carbamide peroxide agent applied during nocturnal hours. The purpose of this randomized double-blind study was to compare the amount of tooth color change in two groups of subjects using dentist-supervised, patient-applied 10% carbamide peroxide gel. One group used Opalescence (Ultradent Products Inc., South Jordan, Utah) and the other NiteWhite Excel (Discus Dental, Inc., Los Angeles, California). Evaluation of tooth color for the six maxillary anterior teeth was done using a Vita shade guide at baseline, 1, 2, and 4 weeks. Subjects were instructed to apply the gel nocturnally using a custom-made soft tray 8 hours per day for 2 weeks. The 16 tabs of the shade guide were ranked according to value from darkest to lightest. The number (1-16) that correlated to the shade tab selected as the match for each tooth was the outcome variable. A Kruskal-Wallis one way analysis of variance on ranks was used. The test revealed no statistically significant difference between Opalescence and NiteWhite Excel for lightening the teeth (p = .807). The color change was still significant after 2 weeks without further bleaching activity. The baseline evaluation of the maxillary incisors and canines for all subjects, regardless of group, demonstrated a significant shade difference, with the canines being darker. This difference was not seen after 2 weeks of active bleaching or at the 4-week evaluation. In this study comparing bleaching products, patients using Opalescence and NiteWhite Excel experienced a significant change in the color of their teeth relative to baseline values after 2 weeks of active treatment.

Stratification in anterior teeth using one dentine shade and a predefined thickness of enamel: a new concept in composite layering--Part I.

PubMed

Manauta, J; Salat, A; Putignano, A; Devoto, W; Paolone, G; Hardan, L S

2014-06-01

Restoring an anterior tooth has always been a challenge, regarding the shade matching, the choice of colors, opacities, translucencies of our composites and the final anatomical outcome. This article proposes a new method for color matching and a clinical stratification using a simple and reproducible procedure for anterior restorations. The physical and optical characteristics of enamel and dentine will be studied and applied to our dental materials that we are using to restore anterior teeth.

Effects of polishing on surface roughness, gloss and color of surface reaction type pre-reacted glass-ionomer filled resin composite.

PubMed

Hosoya, Yumiko; Shiraishi, Takanobu; Odatsu, Tetsuro; Miyazaki, Masashi; García-Godoy, Franklin

2011-06-01

To evaluate the effects of polishing on surface roughness, gloss and color of different shades of surface reaction type pre-reacted glass-ionomer (S-PRG) filled nano-hybrid resin composite. Resin disks of 15 mm diameter and 2 mm thickness and final polish with 1000-grit SiC paper, super fine cut diamond (FG) point, silicon (MFR) point and Super-Snap mini-disk red (SNAP) were made with Beautifil II shades: A2, A20, Inc). One week after curing, the surface roughness, gloss and color were measured. Data was analyzed with ANOVA and Fisher's PLSD with alpha= 0.05 For all shades, the order of roughness (Ra) ranked according to groups of 1000-grit SiC > FG > MFR > SNAP with significant differences among all groups. For all shades, the order of gloss ranked according to groups of SNAP > MFR > FG > 1000-grit SiC with significant differences among the groups except for between MFR and FG without significant difference. The influence of the surface roughness on color differed among the polishing groups and shades. However, the values of the color differences (deltaE*ab) between the polishing groups of all shades were imperceptible to the naked eye.

Changing environmental conditions and applying organic fertilizers in Origanum vulgare L.

PubMed Central

Murillo-Amador, Bernardo; Morales-Prado, Luis E.; Troyo-Diéguez, Enrique; Córdoba-Matson, Miguel V.; Hernández-Montiel, Luis G.; Rueda-Puente, Edgar O.; Nieto-Garibay, Alejandra

2015-01-01

Any improvement in agricultural systems that results in higher production should also reduce negative environmental impacts and enhance sustainability. The aim of this research was to investigate the effect of two different production systems, one open-field and the other shade-enclosure with four bocashi doses, in order to find the best environmental option in terms of yield, physiological and morphometric characteristics in one oregano (Origanum vulgare L.) cultivar. In this study a completely randomized block design was used with four replications and evaluated for photosynthetic and transpiration rate, stomatal conductance, chlorophyll, leaf area and temperature, aerial and roots fresh and dry biomass, fresh and dry yield. The results showed that oregano adapted best to the shade-enclosure with increase yield of fresh and dry leaf weight of 165% and 118%, respectively, when compared to open-field. Also, higher doses of bocashi improved yield in both environments but more so in shade-enclosure. Soil moisture retention was higher in shade-enclosure which was reflected in physiological variables for soil matric potential, transpiration, stomatal conductivity, photosynthesis being significantly higher in shade-enclosure compared to open-field, thus improving yield. It seems that oregano plants can be grown and perform better under shade-enclosure than open-field and bocashi is a suitable organic fertilizer. PMID:26257756

Quality and Quantity Evaluations of Shade Grown Forages

Treesearch

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

2003-01-01

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

Comparison of two low sensitivity whiteners.

PubMed

Callan, Richard S; Browning, William D; Downey, Mary C; Brackett, Martha G

2008-02-01

To evaluate two commercially available doctor-supplied, patient-applied, bleaching systems for their ability to whiten the maxillary anterior teeth while at the same time not causing sensitivity. 46 participants were randomly assigned to one of two groups: One group received Rembrandt Xtra-Comfort and the other group Nite White Excel 2Z. Bleaching stents were fabricated and the bleaching systems were used following manufacturers' instructions. Participants recorded tray use and any sensitivity on a daily basis. Participants bleached for 2 weeks followed by 2 weeks of no bleaching. Color was evaluated at the first, second and fourth week following the initial delivery of bleaching trays. Color change was measured using the Vita Classic Shade Guide arranged by value. As a group, participants in the NW2Z group bleached for 302 days with a total of 48 days (16%) of sensitivity recorded. The Rembrandt Xtra Comfort group bleached for 313 total days with 97 days (31%) of sensitivity recorded. The difference in sensitivity between the two products proved to be statistically significant (Chi-square analysis, P < or = 0.0001). The median shade change for both products following 2 weeks of active treatment was six tabs. At the 4-week evaluation, the median shade change was 5.5 and 6.0 tabs respectively for Rembrandt and Nite White. There was no statistical difference between the products in respect to shade change.

Analytic double product integrals for all-frequency relighting.

PubMed

Wang, Rui; Pan, Minghao; Chen, Weifeng; Ren, Zhong; Zhou, Kun; Hua, Wei; Bao, Hujun

2013-07-01

This paper presents a new technique for real-time relighting of static scenes with all-frequency shadows from complex lighting and highly specular reflections from spatially varying BRDFs. The key idea is to depict the boundaries of visible regions using piecewise linear functions, and convert the shading computation into double product integrals—the integral of the product of lighting and BRDF on visible regions. By representing lighting and BRDF with spherical Gaussians and approximating their product using Legendre polynomials locally in visible regions, we show that such double product integrals can be evaluated in an analytic form. Given the precomputed visibility, our technique computes the visibility boundaries on the fly at each shading point, and performs the analytic integral to evaluate the shading color. The result is a real-time all-frequency relighting technique for static scenes with dynamic, spatially varying BRDFs, which can generate more accurate shadows than the state-of-the-art real-time PRT methods.

Clinical comparison of Colgate Platinum Toothwhitening System and Rembrandt Gel Plus.

PubMed

Kowitz, G M; Nathoo, S A; Rustogi, K N; Chmielewski, M B; Liang, L J; Wong, R

1994-01-01

A 2-week, three-cell study was conducted to evaluate the tooth-whitening efficacy of the Colgate Platinum Professional Toothwhitening System vs Rembrandt Gel Plus (a regimen of products consisting of a 10% carbamide peroxide gel, a whitening toothpaste, and a mouthrinse), and a placebo paste. Seventy subjects completed this parallel, single-blind, three-compartment, randomized clinical study. The subjects were balanced into two groups based on a minimal shade of A3 on the Vita shade guide and assigned a product. The duration of product usage was 1 hour twice daily for 2 weeks. Change in tooth color was measured by reflectance spectroscopy using a colorimeter. The readings were taken in the L*, a*, b* color space at the initiation, at 1 week, and at 2 weeks of the study. Calculation of color change (delta E) was performed using the color difference equation established by the Commission Internationale de L'Eclairage. Visual evaluation of shade changes was performed using the Vita shade guide. Results from this clinical study showed that Colgate Platinum was 77.7% more effective at tooth whitening after 1 week and 41.8% more effective after 2 weeks of treatment vs the Rembrandt regimen. Results showed that the Colgate product is significantly superior vs Rembrandt at increasing tooth whiteness (increase in delta E). Shade guide changes showed an overall improvement of 7.08 Vita tabs for the Colgate product and 5.12 Vita tabs for the Rembrandt regimen.

[Effect of thickness and shade of porcelain of ceramometal restorations on color of gingival porcelain].

PubMed

Sun, Jun; Luo, Yun; Chao, Yong-Lie

2005-06-01

The purpose of this study was to evaluate the color changes of gingival porcelain through varying thickness and shade of porcelain of ceramometal restorations. In this study a spectrophotometer (PR-650) was used for color analysis. The color changes of dentin porcelain and gingival porcelain with three varied thickness (0.3 mm, 0.6 mm and 0.9 mm) were investigated. In addition, the color variances of Shofu vintage porcelain shade A2, A3 and B2 were tested. The results showed that decreased L * value of ceramometal restorations and increased a * value were due to the increase of the gingival porcelain thickness, color measurements showed the same trend as the increased dentin porcelain thickness and the opaque and dentin porcelain with different color affected the appearance of gingival porcelain. The color of gingival porcelain would be changed with the differences of thickness and shade of porcelain of ceramometal restorations.

Measurements of the solar UVR protection provided by shade structures in New Zealand primary schools.

PubMed

Gies, Peter; Mackay, Christina

2004-01-01

To reduce ultraviolet radiation (UVR) exposure during childhood, shade structures are being erected in primary schools to provide areas where children can more safely undertake outdoor activities. This study to evaluate the effectiveness of existing and purpose built shade structures in providing solar UVR protection was carried out on 29 such structures in 10 schools in New Zealand. Measurements of the direct and scattered solar UVR doses within the central region of the shade structures were made during the school lunch break period using UVR-sensitive polysulfone film badges. These measurements indicate that many of the structures had UVR protection factors (PF) of 4-8, which was sufficient to provide protection during the school lunch hour. However, of the 29 structures examined, only six would meet the suggested requirements of UVR PF greater than 15 required to provide all-day protection.

Influence of Color Education and Training on Shade Matching Skills.

PubMed

Ristic, Ivan; Stankovic, Sasa; Paravina, Rade D

2016-09-01

To evaluate the influence of education and training on quality of tooth color matching. Dental students (N = 174), matched the color of eight shade tabs in a viewing booth, using VITA Linearguide 3D-Master shade guide. The experimental group had color education and training between the before and after session. The control group did not have any additional information in between two sessions. Color differences between the task tabs and selected tabs were calculated using CIE formulas. The score for the best match (smallest color difference) was 10 points, the 2nd best match 9 points, down to 1 point for the 10th best match. Means and standard deviations were calculated. Differences were analyzed using the Student t-test. Shade matching scores in the experimental group were significantly better after education and training (p < 0.001), with a mean score before and after shade matching sessions of 7.06 (1.19) and 8.43 (0.92), respectively. The percentage of students in the experimental group that selected one of three best matches increased 24.3%. The control group exhibited no significant improvement in the after session. Within the limitations of the study, education and training improved students' shade matching skills. While the vast majority of dental restorations and practically all restorations in the esthetic zone are tooth colored, the profession as a whole is far from perfect when it comes to accurate shade matching. Education and training can improve shade matching ability: enhanced esthetics of dental restorations, increased patient satisfaction, and a reduced number of color corrections are some of the notable benefits and rewards. (J Esthet Restor Dent 00:000-000, 2016) J Esthet Restor Dent 28:287-294, 2016). © 2016 Wiley Periodicals, Inc.

Difference in the color stability of direct and indirect resin composites

PubMed Central

LEE, Yong-Keun; YU, Bin; LIM, Ho-Nam; LIM, Jin Ik

2011-01-01

Indirect resin composites are generally regarded to have better color stability than direct resin composites since they possess higher conversion degree Objective The present study aimed at comparing the changes in color (∆E) and color coordinates (∆L, ∆a and ∆b) of one direct (Estelite Sigma: 16 shades) and 2 indirect resin composites (BelleGlass NG: 16 shades; Sinfony: 26 shades) after thermocycling. Material and Methods Resins were packed into a mold and light cured; post-curing was performed on indirect resins. Changes in color and color coordinates of 1-mm-thick specimens were determined after 5,000 cycles of thermocycling on a spectrophotometer. Results ∆E values were in the range of 0.3 to 1.2 units for direct resins, and 0.3 to 1.5 units for indirect resins, which were clinically acceptable (∆E<3.3). Based on t-test, ∆E values were not significantly different by the type of resins (p>0.05), while ∆L, ∆a and ∆b values were significantly different by the type of resins (p<0.05). For indirect resins, ∆E values were influenced by the brand, shade group and shade designation based on three-way ANOVA (p<0.05). Conclusion Direct and indirect resin composites showed similar color stability after 5,000 cycles of thermocycling; however, their changes in the color coordinates were different. PMID:21552717

Developmental and reproductive performance of a specialist herbivore depend on seasonality of, and light conditions experienced by, the host plant

PubMed Central

Zachariades, Costas; Heshula, Lelethu U.; Hill, Martin P.

2018-01-01

Host plant phenology (as influenced by seasonality) and light-mediated changes in the phenotypic and phytochemical properties of leaves have been hypothesised to equivocally influence insect herbivore performance. Here, we examined the effects of seasonality, through host plant phenology (late growth-season = autumn vs flowering-season = winter) and light environment (shade vs full-sun habitat) on the leaf characteristics of the invasive alien plant, Chromolaena odorata. In addition, the performance of a specialist folivore, Pareuchaetes insulata, feeding on leaves obtained from both shaded and full-sun habitats during autumn and winter, was evaluated over two generations. Foliar nitrogen and magnesium contents were generally higher in shaded plants with much higher levels during winter. Leaf water content was higher in shaded and in autumn plants. Total non-structural carbohydrate (TNC) and phosphorus contents did not differ as a function of season, but were higher in shaded foliage compared to full-sun leaves. Leaf toughness was noticeably higher on plants growing in full-sun during winter. With the exception of shaded leaves in autumn that supported the best performance [fastest development, heaviest pupal mass, and highest growth rate and Host Suitability Index (HSI) score], full-sun foliage in autumn surprisingly also supported an improved performance of the moth compared to shaded or full-sun leaves in winter. Our findings suggest that shaded and autumn foliage are nutritionally more suitable for the growth and reproduction of P. insulata. However, the heavier pupal mass, increased number of eggs and higher HSI score in individuals that fed on full-sun foliage in autumn compared to their counterparts that fed on shaded or full-sun foliage in winter suggest that full-sun foliage during autumn is also a suitable food source for larvae of the moth. In sum, our study demonstrates that seasonal and light-modulated changes in leaf characteristics can affect insect folivore performance in ways that are not linear. PMID:29304104

Developmental and reproductive performance of a specialist herbivore depend on seasonality of, and light conditions experienced by, the host plant.

PubMed

Uyi, Osariyekemwen O; Zachariades, Costas; Heshula, Lelethu U; Hill, Martin P

2018-01-01

Host plant phenology (as influenced by seasonality) and light-mediated changes in the phenotypic and phytochemical properties of leaves have been hypothesised to equivocally influence insect herbivore performance. Here, we examined the effects of seasonality, through host plant phenology (late growth-season = autumn vs flowering-season = winter) and light environment (shade vs full-sun habitat) on the leaf characteristics of the invasive alien plant, Chromolaena odorata. In addition, the performance of a specialist folivore, Pareuchaetes insulata, feeding on leaves obtained from both shaded and full-sun habitats during autumn and winter, was evaluated over two generations. Foliar nitrogen and magnesium contents were generally higher in shaded plants with much higher levels during winter. Leaf water content was higher in shaded and in autumn plants. Total non-structural carbohydrate (TNC) and phosphorus contents did not differ as a function of season, but were higher in shaded foliage compared to full-sun leaves. Leaf toughness was noticeably higher on plants growing in full-sun during winter. With the exception of shaded leaves in autumn that supported the best performance [fastest development, heaviest pupal mass, and highest growth rate and Host Suitability Index (HSI) score], full-sun foliage in autumn surprisingly also supported an improved performance of the moth compared to shaded or full-sun leaves in winter. Our findings suggest that shaded and autumn foliage are nutritionally more suitable for the growth and reproduction of P. insulata. However, the heavier pupal mass, increased number of eggs and higher HSI score in individuals that fed on full-sun foliage in autumn compared to their counterparts that fed on shaded or full-sun foliage in winter suggest that full-sun foliage during autumn is also a suitable food source for larvae of the moth. In sum, our study demonstrates that seasonal and light-modulated changes in leaf characteristics can affect insect folivore performance in ways that are not linear.

The effect of multicolored machinable ceramics on the esthetics of all-ceramic crowns.

PubMed

Reich, Sven; Hornberger, Helga

2002-07-01

Computer-aided design/computer-assisted machining systems offer the possibility of fabricating restorations from one machinable ceramic block. Whether multishaded blocks improve esthetic results and are a viable alternative to individually stained ceramics has not been fully determined. The aim of this investigation was to examine the effect of multishaded blocks on the esthetic appearance of all-ceramic CEREC crowns and compare these crowns with single-shade and stained restorations. Ten subjects were included in this study. For each subject, 6 different crowns were milled with the use of a CEREC machine. One crown was milled from each of the following machinable ceramic materials: CEREC Vitablocs Mark II in classic colors; Vitablocs Mark II in 3D-Master colors; Vitablocs Mark II in either classic or 3D-Master colors, with additional staining; Megadenta Bloxx multishaded; Mark II experimental multilayer; and an experimental multilayer leucite ceramic. Three independent examiners assessed the esthetic appearance of crowns fabricated to match each subject's anterior tooth shade. A scale of 1 to 6 was used to score the shade match and esthetic adaptation of each crown, with 1 representing excellent characteristics and 3.5 serving as the threshold for clinical acceptability. The examiners' scores were averaged, and the mean values were analyzed with the Wilcoxon signed rank test (P

Evaluation of tourists' UV exposure in Paris.

PubMed

Mahé, E; Corrêa, M P; Godin-Beekmann, S; Haeffelin, M; Jégou, F; Saiag, P; Beauchet, A

2013-03-01

Ultraviolet (UV) exposure is one of the most important risk factor for skin cancers. If UV hazard has been evaluated in tropical countries or in some population - children, outdoor activities - little information is available about UV hazard in high latitude towns like Paris, considered as the most 'charismatic city' in the world. To evaluate UV exposure in Paris in spring, in sun and shade, in real life conditions. We evaluated erythemal UV exposure, during four sunny days in May-June in eight Paris touristic sites during peak hours (2 days), and during two walks in touristic downtown of Paris. Measures were performed in sun and shade. UV radiation exposure was evaluated with UV index performed with a 'Solarmeter ultraviolet index (UVI)' and UV dose with 'standard erythema dose' (SED) and 'minimal erythema dose' (MED) calculations. Despite 'average' UVI in sunny conditions, a 4-h sun exposure reaches 13-20 SED and 3-10 MED according to phototype. Clouds were inefficient to protect against UV. Shade of places reduces moderately UVI (50-60%) in forecourts. Exposure during 1-h walk reach at least one MED in real life conditions for skin phototypes I-IV. UV risk for tourist is quite high in spring in Paris. UVI remains high despite high cloud fraction. Shade reduces UVI, but UV protection factor is only 2-3 in large places such as Place Notre Dame and Place Charles de Gaulle. So sun protection campaigns should be proposed, and sun protective strategies could be integrated in urban planning. © 2012 The Authors. Journal of the European Academy of Dermatology and Venereology © 2012 European Academy of Dermatology and Venereology.

Shade matching performance of normal and color vision-deficient dental professionals with standard daylight and tungsten illuminants.

PubMed

Gokce, Hasan Suat; Piskin, Bulent; Ceyhan, Dogan; Gokce, Sila Mermut; Arisan, Volkan

2010-03-01

The lighting conditions of the environment and visual deficiencies such as red-green color vision deficiency affect the clinical shade matching performance of dental professionals. The purpose of this study was to evaluate the shade matching performance of normal and color vision-deficient dental professionals with standard daylight and tungsten illuminants. Two sets of porcelain disc replicas of 16 shade guide tabs (VITA Lumin) were manufactured to exact L*a*b* values by using a colorimeter. Then these twin porcelain discs (13 mm x 2.4 mm) were mixed up and placed into a color-matching cabinet that standardized the lighting conditions for the observation tests. Normal and red-green color vision-deficient dental professionals were asked to match the 32 porcelain discs using standard artificial daylight D65 (high color temperature) and tungsten filament lamp light (T) (low color temperature) illuminants. The results were analyzed by repeated-measures ANOVA and paired and independent samples t tests for the differences between dental professionals and differences between the illuminants (alpha=.05). Regarding the sum of the correct shade match scores of all observations with both illuminants, the difference between normal vision and red-green color vision-deficient dental professional groups was not statistically significant (F=4.132; P=.054). However, the correct shade match scores of each group were significantly different for each illuminant (P<.005). The correct shade matching scores of normal color vision dental professionals were significantly higher with D65 illuminant (t=7.004; P<.001). Color matching scores of red-green color vision-deficient dental professionals (approximately 5.7 more pairs than with D65) were significantly higher with T illuminant (t=5.977; P<.001). CONCLUSIONS.: Within the limitations of this study, the shade matching performance of dental professionals was affected by color vision deficiency and the color temperature of the illuminant. The color vision-deficient group was notably unsuccessful with the D65 illuminant in shade matching. In contrast, there was a significant increase in the shade matching performance of the color vision-deficient group with T illuminant. The lower color temperature illuminant dramatically decreased the normal color vision groups' correct shade matching score. (c) 2010 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Thermal Shock Behavior of Single Crystal Oxide Refractive Concentrators for High Temperatures Solar Thermal Propulsion

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Choi, Sung R.; Jacobson, Nathan S.; Miller, Robert A.

1999-01-01

Single crystal oxides such as yttria-stabilized zirconia (Y2O3-ZrO2), yttrium-aluminum-garnet (Y3Al5O12, or YAG), magnesium oxide (MgO) and sapphire (Al2O3) have been considered as refractive secondary concentrator materials for high temperature solar propulsion applications. However, thermal mechanical reliability of the oxide components in severe thermal environments during space mission sun/shade transitions is of great concern. In this paper, critical mechanical properties of these oxide crystals are determined by the indentation technique. Thermal shock resistance of the oxides is evaluated using a high power CO, laser under high temperature-high thermal gradients. Thermal stress fracture behavior and failure mechanisms of these oxide materials are investigated under various temperature and heating conditions.

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

Evaluating optical hazards from plasma arc cutting.

PubMed

Glassford, Eric; Burr, Gregory

2018-01-01

The Health Hazard Evaluation Program of the National Institute for Occupational Safety and Health evaluated a steel building materials manufacturer. The employer requested the evaluation because of concerns about optical radiation hazards from a plasma arc cutting system and the need to clarify eye protection requirements for plasma operators, other employees, and visitors. The strength of the ultraviolet radiation, visible radiation (light), and infrared radiation generated by the plasma arc cutter was measured at various distances from the source and at different operating amperages. Investigators also observed employees performing the plasma arc cutting. Optical radiation above safe levels for the unprotected eyes in the ultraviolet-C, ultraviolet-B, and visible light ranges were found during plasma arc cutting. In contrast, infrared and ultraviolet-A radiation levels during plasma arc cutting were similar to background levels. The highest non-ionizing radiation exposures occurred when no welding curtains were used. A plasma arc welding curtain in place did not eliminate optical radiation hazards to the plasma arc operator or to nearby employees. In most instances, the measured intensities for visible light, UV-C, and UV-B resulted in welding shade lens numbers that were lower than those stipulated in the OSHA Filter Lenses for Protection Against Radiant Energy table in 29 CFR 1910.133(a)(5). [1] Investigators recommended using a welding curtain that enclosed the plasma arc, posting optical radiation warning signs in the plasma arc cutter area, installing audible or visual warning cues when the plasma arc cutter was operating, and using welding shades that covered the plasma arc cutter operator's face to protect skin from ultraviolet radiation hazards.

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.

Effect of light-curing units, post-cured time and shade of resin cement on knoop hardness.

PubMed

Reges, Rogério Vieira; Costa, Ana Rosa; Correr, Américo Bortolazzo; Piva, Evandro; Puppin-Rontani, Regina Maria; Sinhoreti, Mário Alexandre Coelho; Correr-Sobrinho, Lourenço

2009-01-01

The aim of this study was to evaluate the Knoop hardness after 15 min and 24 h of different shades of a dual-cured resin-based cement after indirect photoactivation (ceramic restoration) with 2 light-curing units (LCUs). The resin cement Variolink II (Ivoclar Vivadent) shade XL, A2, A3 and opaque were mixed with the catalyst paste and inserted into a black Teflon mold (5 mm diameter x 1 mm high). A transparent strip was placed over the mold and a ceramic disc (Duceram Plus, shade A3) was positioned over the resin cement. Light-activation was performed through the ceramic for 40 s using quartz-tungsten-halogen (QTH) (XL 2500; 3M ESPE) or light-emitting diode (LED) (Ultrablue Is, DMC) LCUs with power density of 615 and 610 mW/cm(2), respectively. The Koop hardness was measured using a microhardness tester HMV 2 (Shimadzu) after 15 min or 24 h. Four indentations were made in each specimen. Data were subjected to ANOVA and Tukey's test (alpha=0.05). The QTH LCU provided significantly higher (p<0.05) KHN values than the LED LCU. When the post-cure times were compared for the same shade, QTH and LED at 24 h provided significantly higher (p<0.05) KHN values than at 15 min. It may be concluded that the Knoop hardness was generally dependent on the LCU and post-cure time. The opaque shade of the resin cement showed lower Knoop hardness than the other shades for both LCUs and post-cure times.

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.

Phenotypic plasticity of Neonotonia wightii and Pueraria phaseoloides grown under different light intensities.

PubMed

Santos, Leonardo D T; Da Cruz, Leandro R; Dos Santos, Samuel A; Sant'anna-Santos, Bruno F; Dos Santos, Izabela T; De Oliveira, Ariane M; Barros, Rodrigo E; Santos, Márcia V; Faria, Rodrigo M

2015-03-01

Plants have the ability to undergo morphophysiological changes based on availability of light. The present study evaluated biomass accumulation, leaf morphoanatomy and physiology of Neonotonia wightii and Pueraria phaseoloides grown in full sunlight, as well as in 30% and 50% shade. Two assays were performed, one for each species, using a randomized block design with 10 replicates. A higher accumulation of fresh mass in the shoot of the plants was observed for both species under cultivation in 50% shade, while no differences were detected between the full sunlight and 30% shade. N. wightii and P. phaseoloides showed increase in area and reduction in thickness leaf when cultivated in 50% shade. There were no changes in photosynthetic rate, stomatal conductance, water use efficiency and evapotranspiration of P. phaseoloides plants because growth environment. However, the shade treatments caused alterations in physiological parameters of N. wightii. In both species, structural changes in the mesophyll occurred depending on the availability of light; however, the amount of leaf blade tissue remained unaltered. Despite the influence of light intensity variation on the morphophysiological plasticity of N. wightii and P. phaseoloides, no effects on biomass accumulation were observed in response to light.

Influence of artificial accelerated aging on the color stability and opacity of composites of different shades.

PubMed

Mundim, F M; Da Fonseca Roberti Garcia, L; Silva Sousa, A B; Cruvinel, D R; De Carvalho Panzeri Pires-De-Souza, F

2010-10-01

The aim of this study was to evaluate the influence of artificial accelerated aging on the color stability and opacity of composites of different shades. Four composites for direct use (Heliomolar, 4 Seasons, Tetric EvoCeram; QuiXfil) and one for indirect use (SR Adoro) in two shades were used: light (A2) and dark (C3 for direct, and D4 for indirect composite). QuiXfil was obtained in Universal shade. A Teflon matrix (12 X 2 mm) was used to obtain 54 specimens (N=6), which were submitted to color and opacity analysis (Spectrophotometer PCB 6807, Byk Gardner) before and after artificial accelerated aging for 384 hours. After the statistical analysis (2-way ANOVA - Bonferroni - P<0.05), significant color alteration was observed in the light and dark composites studied (P<0.05), with the exception of QuiXfil. Composite 4 Seasons/C3 showed less color alteration (ΔE=0.91). The opacity alteration (ΔOP) was higher for light composites. Artificial accelerated aging interfered in the optical properties assessed; however, the alterations seemed to be more related to the composites composition than to their shade.

Effect of shade on animal welfare, growth performance, and carcass characteristics in large pens of beef cattle fed a beta agonist in a commercial feedlot.

PubMed

Hagenmaier, J A; Reinhardt, C D; Bartle, S J; Thomson, D U

2016-12-01

Feedlot cattle ( = 1,395; BW = 568 ± 43 kg) were used to evaluate the effects of shade on animal welfare, growth performance, and carcass quality during the summer of 2013 in a Kansas commercial feedlot. Seven lots of predominately black steers and heifers (4 and 3, respectively) visually determined to be approaching the final mo on feed were identified, randomly gate-sorted, and allocated to pens located across the feed alley from each other to receive 1 of 2 treatments: 1) Shade (mean shade area = 1.5 m/ animal) or 2) No shade. Shade was provided using a 13-ounce polyethylene fabric and pens were oriented northwest to southeast. The mean starting date was June 13 and the mean days on feed for lots while on the study was 38 d. Cattle were fed a 77.67% DM steam-flaked corn-based diet and had ad libitum access to water throughout the duration of the trial. Zilpaterol hydrochloride (ZIL) was included in the finishing ration at an inclusion rate of 8.3 mg/kg of DM for the last 20 d on feed with a 3 d withdrawal period. Pen floor temperatures (PFT) were measured using an infrared thermometer and prevalence of cattle open-mouth breathing (OMB) was recorded on a pen basis. In addition to shade treatment, the effect of temperature humidity index (THI) on PFT and OMB was analyzed by classifying days as either "Alert" (THI < 79) or "Danger" (THI > 79). On the day of slaughter, pens within a replicate were kept separate through all stages of the marketing channel from loading at the feedlot until stunning at the plant. Pen served as the experimental unit for all measurements. There was a THI × shade treatment interaction for PFT and OMB ( < 0.001) where days classified as "Danger" increased PFT and prevalence of OMB compared to "Alert" days in unshaded but not shaded cattle. Shaded cattle had greater DMI ( = 0.01); however, unshaded cattle had greater G:F ( = 0.05) and therefore no differences were observed in ADG ( = 0.39). Shaded cattle had greater dressing percentage ( = 0.01), although HCW, LM area, fat thickness, marbling score, and quality grade did not differ between treatments ( > 0.05). Heat stress, a significant animal welfare concern and cause of reduced performance in feedlot cattle during the final phase of the feeding period, was alleviated in shaded cattle and illustrates the importance of shade provision as 1 tool to protect the welfare and increase feed consumption in large pens of feedlot cattle during hot summer months.

Vegetation patches improve the establishment of Salvia mexicana seedlings by modifying microclimatic conditions

NASA Astrophysics Data System (ADS)

Mendoza-Hernández, Pedro E.; Rosete-Rodríguez, Alejandra; Sánchez-Coronado, María E.; Orozco, Susana; Pedrero-López, Luis; Méndez, Ignacio; Orozco-Segovia, Alma

2014-07-01

Human disturbance has disrupted the dynamics of plant communities. To restore these dynamics, we could take advantage of the microclimatic conditions generated by remaining patches of vegetation and plastic mulch. These microclimatic conditions might have great importance in restoring disturbed lava fields located south of Mexico City, where the rock is exposed and the soil is shallow. We evaluated the effects of both the shade projected by vegetation patches and plastic mulch on the mean monthly soil surface temperature ( T ss) and photosynthetic photon flux density (PPFD) and on the survival and growth of Salvia mexicana throughout the year. This species was used as a phytometer of microsite quality. Shade reduced the T ss to a greater extent than mulch did. Both survival and growth were enhanced by shade and mulch, and the PPFD was related with seedling growth. During the dry season, plant biomass was lost, and there was a negative effect of PPFD on plant growth. At micro-meteorological scales, the use of shade projected by patches of vegetation and mulch significantly reduced the mortality of S. mexicana and enhanced its growth. Survival and growth of this plant depended on the environmental quality of microsites on a small scale, which was determined by the environmental heterogeneity of the patches and the landscape. For plant restoration, microsite quality must be evaluated on small scales, but on a large scale it may be enough to take advantage of landscape shade dynamics and the use of mulch to increase plant survival and growth.

Vegetation patches improve the establishment of Salvia mexicana seedlings by modifying microclimatic conditions.

PubMed

Mendoza-Hernández, Pedro E; Rosete-Rodríguez, Alejandra; Sánchez-Coronado, María E; Orozco, Susana; Pedrero-López, Luis; Méndez, Ignacio; Orozco-Segovia, Alma

2014-07-01

Human disturbance has disrupted the dynamics of plant communities. To restore these dynamics, we could take advantage of the microclimatic conditions generated by remaining patches of vegetation and plastic mulch. These microclimatic conditions might have great importance in restoring disturbed lava fields located south of Mexico City, where the rock is exposed and the soil is shallow. We evaluated the effects of both the shade projected by vegetation patches and plastic mulch on the mean monthly soil surface temperature (Tss) and photosynthetic photon flux density (PPFD) and on the survival and growth of Salvia mexicana throughout the year. This species was used as a phytometer of microsite quality. Shade reduced the T ss to a greater extent than mulch did. Both survival and growth were enhanced by shade and mulch, and the PPFD was related with seedling growth. During the dry season, plant biomass was lost, and there was a negative effect of PPFD on plant growth. At micro-meteorological scales, the use of shade projected by patches of vegetation and mulch significantly reduced the mortality of S. mexicana and enhanced its growth. Survival and growth of this plant depended on the environmental quality of microsites on a small scale, which was determined by the environmental heterogeneity of the patches and the landscape. For plant restoration, microsite quality must be evaluated on small scales, but on a large scale it may be enough to take advantage of landscape shade dynamics and the use of mulch to increase plant survival and growth.

Changes in chroma of two indirect composite materials polymerized with different polymerization systems.

PubMed

Ayano, Michiya

2012-01-01

This study evaluated chroma change in two composite materials (Sinfony and Pearleste) polymerized with two different systems. Disk specimens were prepared using a metal halide unit (Hyper LII) and an exposure time of 60 to 180 s. The proprietary polymerization systems (Visio and Pearlcure systems) were used as the reference polymerization modes. After storage at 37°C for 24 h, CIE 1976 L*a*b* values were measured by using a dental chroma meter (ShadeEye NCC) with a gray background. The specimens were then immersed in water or tea. Color change from baseline to 4 weeks was evaluated by measuring ΔL*, Δa*, and Δb*, after which ΔE*(ab) values were calculated. The brightness of Sinfony specimens was reduced by tea immersion. The color of both materials shifted to yellow after tea immersion, although color change in Sinfony specimens was greater than that in Pearleste specimens. For both materials, color change was less after polymerization with the metal halide unit. In conclusion, Sinfony polymerized with the Hyper LII unit, and Pearleste polymerized with either system, were stable against discoloration due to tea immersion.

Influence of implant abutment material on the color of different ceramic crown systems.

PubMed

Dede, Doğu Ömür; Armağanci, Arzu; Ceylan, Gözlem; Celik, Ersan; Cankaya, Soner; Yilmaz, Burak

2016-11-01

Ceramics are widely used for anterior restorations; however, clinical color reproduction still constitutes a challenge particularly when the ceramic crowns are used on titanium implant abutments. The purpose of this in vitro study was to investigate the effect of implant abutment material on the color of different ceramic material systems. Forty disks (11×1.5 mm, shade A2) were fabricated from medium-opacity (mo) and high-translucency (ht) lithium disilicate (IPS e.max) blocks, an aluminous ceramic (VITA In-Ceram Alumina), and a zirconia (Zirkonzahn) ceramic system. Disks were fabricated to represent 3 different implant abutments (zirconia, gold-palladium, and titanium) and dentin (composite resin, A2 shade) as background (11×2 mm). Disk-shaped composite resin specimens in A2 shade were fabricated to represent the cement layer. The color measurements of ceramic specimens were made on composite resin abutment materials using a spectrophotometer. CIELab color coordinates were recorded, and the color coordinates measured on composite resin background served as the control group. Color differences (ΔE 00 ) between the control and test groups were calculated. The data were analyzed with 2-way analysis of variance (ANOVA) and compared with the Tukey HSD test (α=.05). The ceramics system, abutment material, and their interaction were significant for ΔE 00 values (P<.001). Clinically unacceptable results (ΔE 00 >2.25) were observed for lithium disilicate ceramics on titanium abutments (2.46-2.50). The ΔE 00 values of lithium disilicate ceramics for gold-palladium and titanium abutments were significantly higher than for other groups (P<.05). The color results (ΔE 00 >2.25) of an implant-supported lithium disilicate ceramic restoration may be clinically unacceptable if it is fabricated over a titanium abutment. Zirconia may be a more suitable abutment material for implant-supported ceramic restorations. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

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

PubMed

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.

Impact of background on color, transmittance, and fluorescence of leucite based ceramics.

PubMed

Rafael, Caroline Freitas; Güth, Jan-Frederik; Kauling, Ana Elisa Colle; Cesar, Paulo Francisco; Volpato, Claudia Angelo Mazieiro; Liebermann, Anja

2017-07-26

This study evaluated the impact of tooth shade on differences in color (∆E), lightness (∆L), chromaticity coordinates a*/b* (∆a and ∆b), transmittance and the degree of fluorescence of CAD/CAM leucite based ceramic (LBC). Ten disks were fabricated of LBC; Empress CAD, A2, thickness of 1.5 mm and eight disks of resin-nano-ceramic (RNC; Lava Ultimate) in different colors to simulate variations in substrate shade. The associations of LBC disks with different color substrates were analyzed with a spectrophotometer; ∆E, ∆L*, ∆a*, ∆b*, and transmittance were measured and calculated. Fluorescence was evaluated with a fluorescence system (Fluorescence System, Biopdi). All substrate shades influenced the optical properties of LBC, with regard to color, luminosity, coordinate a* and b*, transmittance, and fluorescence (p<0.001). Substrate colors with high saturation (A3.5 and C2) presented highest impact, whereas colors with lowest saturations (BL, B1) showed less impact. Substrate color influenced the optical properties of ceramic restorations.

Direct quantitative evaluation of disease symptoms on living plant leaves growing under natural light.

PubMed

Matsunaga, Tomoko M; Ogawa, Daisuke; Taguchi-Shiobara, Fumio; Ishimoto, Masao; Matsunaga, Sachihiro; Habu, Yoshiki

2017-06-01

Leaf color is an important indicator when evaluating plant growth and responses to biotic/abiotic stress. Acquisition of images by digital cameras allows analysis and long-term storage of the acquired images. However, under field conditions, where light intensity can fluctuate and other factors (shade, reflection, and background, etc.) vary, stable and reproducible measurement and quantification of leaf color are hard to achieve. Digital scanners provide fixed conditions for obtaining image data, allowing stable and reliable comparison among samples, but require detached plant materials to capture images, and the destructive processes involved often induce deformation of plant materials (curled leaves and faded colors, etc.). In this study, by using a lightweight digital scanner connected to a mobile computer, we obtained digital image data from intact plant leaves grown in natural-light greenhouses without detaching the targets. We took images of soybean leaves infected by Xanthomonas campestris pv. glycines , and distinctively quantified two disease symptoms (brown lesions and yellow halos) using freely available image processing software. The image data were amenable to quantitative and statistical analyses, allowing precise and objective evaluation of disease resistance.

Colour stability of denture teeth submitted to different cleaning protocols and accelerated artificial aging.

PubMed

Freire, T S; Aguilar, F G; Garcia, L da Fonseca Roberti; Pires-de-Souza, F de Carvalho Panzeri

2014-03-01

Acrylic resin is widely used for artificial teeth manufacturing due to several important characteristics; however, this material do not present acceptable colour stability over the course of time. This study evaluated the effect of different cleaning protocols and accelerated artificial aging on colour stability of denture teeth made of acrylic resin. Sixty denture teeth in dark and light shades were used, and separated according to the treatment to which they were submitted. Results demonstrated that colour stability of artificial teeth is influenced by the cleaning solution and artificial aging, being dark teeth more susceptible to colour alteration than lighter ones.

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.

Shading correction assisted iterative cone-beam CT reconstruction

NASA Astrophysics Data System (ADS)

Yang, Chunlin; Wu, Pengwei; Gong, Shutao; Wang, Jing; Lyu, Qihui; Tang, Xiangyang; Niu, Tianye

2017-11-01

Recent advances in total variation (TV) technology enable accurate CT image reconstruction from highly under-sampled and noisy projection data. The standard iterative reconstruction algorithms, which work well in conventional CT imaging, fail to perform as expected in cone beam CT (CBCT) applications, wherein the non-ideal physics issues, including scatter and beam hardening, are more severe. These physics issues result in large areas of shading artifacts and cause deterioration to the piecewise constant property assumed in reconstructed images. To overcome this obstacle, we incorporate a shading correction scheme into low-dose CBCT reconstruction and propose a clinically acceptable and stable three-dimensional iterative reconstruction method that is referred to as the shading correction assisted iterative reconstruction. In the proposed method, we modify the TV regularization term by adding a shading compensation image to the reconstructed image to compensate for the shading artifacts while leaving the data fidelity term intact. This compensation image is generated empirically, using image segmentation and low-pass filtering, and updated in the iterative process whenever necessary. When the compensation image is determined, the objective function is minimized using the fast iterative shrinkage-thresholding algorithm accelerated on a graphic processing unit. The proposed method is evaluated using CBCT projection data of the Catphan© 600 phantom and two pelvis patients. Compared with the iterative reconstruction without shading correction, the proposed method reduces the overall CT number error from around 200 HU to be around 25 HU and increases the spatial uniformity by a factor of 20 percent, given the same number of sparsely sampled projections. A clinically acceptable and stable iterative reconstruction algorithm for CBCT is proposed in this paper. Differing from the existing algorithms, this algorithm incorporates a shading correction scheme into the low-dose CBCT reconstruction and achieves more stable optimization path and more clinically acceptable reconstructed image. The method proposed by us does not rely on prior information and thus is practically attractive to the applications of low-dose CBCT imaging in the clinic.

Quality and yield of seven forages grown under partial shading of a simulated silvopastoral system in east Texas

Treesearch

J. Hill; K. Farrish; B. Oswald; L. Young; A. Shadow

2016-01-01

The goal of this project is to evaluate the growth and nutritional characteristics of seven forages, including various warm season native grasses, grown under simulated partial shading (50 percent typical of a loblolly pine silvopastoral system in east Texas. The results are from year two of a three year study. In order to meet the overall objective, individual,...

The repeatability of an intraoral dental colorimeter.

PubMed

Tung, Francis F; Goldstein, Gary R; Jang, Sungkoo; Hittelman, Eugene

2002-12-01

Characterizing and reproducing color remain one of the most challenging aspects of dentistry. A relatively new intraoral colorimeter measures the color of natural teeth and metal-ceramic restorations and prints out a color recipe for the Vintage Halo Porcelain System. The reliability of the colorimeter is unknown. The purpose of this study was to evaluate the reliability of a contact dental colorimeter and to correlate the shade registered by the colorimeter with the shade selected by experienced clinicians. In part I of the study, 2 examiners (A and B) took 2 colorimeter measurements from the maxillary right central incisors of 11 subjects. The examiners were blinded to their own data and those of other investigators. The readings were repeated 3 weeks later with the same protocol. The Cronbach alpha reliability coefficient was used to analyze the collected data. In part II of the study, 2 experienced clinicians (examiners D and E) selected a shade from the classic Vita Lumin Vacuum shade guide for the maxillary right central incisors of the same 11 subjects. The clinicians were blinded to each other's selections and the colorimeter readings. It should be noted that the manufacturer of the colorimeter uses the terms shade, value, and hue to represent chroma, value, and hue, respectively, as defined in the Glossary of Prosthodontic Terms (J Prosthet Dent 1999;81:39-110). The reliability analysis results for each of the combined trials for shade, value, and hue were all >.94. The interexaminer reliability alpha values were >.9 for shade and value and.64 to.74 for hue. The interexaminer alpha represented the value range of each of 4 measurements. The intraexaminer reliability alpha values for shade, value, and hue were.99,.95, and.96 for examiner A and.99,.93, and.97 for examiner B, respectively. In part II of the study, the colorimeter agreed with itself 82% of the time, whereas clinicians agreed with each other on the selected shade 73% of the time. Selections made by the colorimeter and the clinicians matched 55% to 64% of the time. Within the limitations of this study, the colorimeter reliably measured the color of natural teeth.

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 and attractive as a general solution to CT shading correction.

Regulation of tomato fruit ascorbate content is more highly dependent on fruit irradiance than leaf irradiance.

PubMed

Gautier, Hélène; Massot, Capucine; Stevens, Rebecca; Sérino, Sylvie; Génard, Michel

2009-02-01

The mechanisms involving light control of vitamin C content in fruits are not yet fully understood. The present study aimed to evaluate the impact of fruit and leaf shading on ascorbate (AsA) accumulation in tomato fruit and to determine how fruit sugar content (as an AsA precursor) affected AsA content. Cherry tomato plants were grown in a glasshouse. The control treatment (normally irradiated fruits and irradiated leaves) was compared with the whole-plant shading treatment and with leaf or fruit shading treatments in fruits harvested at breaker stage. In a second experiment, the correlation between sugars and AsA was studied during ripening. Fruit shading was the most effective treatment in reducing fruit AsA content. Under normal conditions, AsA and sugar content were correlated and increased with the ripening stage. Reducing fruit irradiance strongly decreased the reduced AsA content (-74 %), without affecting sugars, so that sugar and reduced AsA were no longer correlated. Leaf shading delayed fruit ripening: it increased the accumulation of oxidized AsA in green fruits (+98 %), whereas it decreased the reduced AsA content in orange fruits (-19 %), suggesting that fruit AsA metabolism also depends on leaf irradiance. Under fruit shading only, the absence of a correlation between sugars and reduced AsA content indicated that fruit AsA content was not limited by leaf photosynthesis or sugar substrate, but strongly depended on fruit irradiance. Leaf shading most probably affected fruit AsA content by delaying fruit ripening, and suggested a complex regulation of AsA metabolism which depends on both fruit and leaf irradiance and fruit ripening stage.

Regulation of tomato fruit ascorbate content is more highly dependent on fruit irradiance than leaf irradiance

PubMed Central

Gautier, Hélène; Massot, Capucine; Stevens, Rebecca; Sérino, Sylvie; Génard, Michel

2009-01-01

Background and Aims The mechanisms involving light control of vitamin C content in fruits are not yet fully understood. The present study aimed to evaluate the impact of fruit and leaf shading on ascorbate (AsA) accumulation in tomato fruit and to determine how fruit sugar content (as an AsA precursor) affected AsA content. Methods Cherry tomato plants were grown in a glasshouse. The control treatment (normally irradiated fruits and irradiated leaves) was compared with the whole-plant shading treatment and with leaf or fruit shading treatments in fruits harvested at breaker stage. In a second experiment, the correlation between sugars and AsA was studied during ripening. Key Results Fruit shading was the most effective treatment in reducing fruit AsA content. Under normal conditions, AsA and sugar content were correlated and increased with the ripening stage. Reducing fruit irradiance strongly decreased the reduced AsA content (−74 %), without affecting sugars, so that sugar and reduced AsA were no longer correlated. Leaf shading delayed fruit ripening: it increased the accumulation of oxidized AsA in green fruits (+98 %), whereas it decreased the reduced AsA content in orange fruits (−19 %), suggesting that fruit AsA metabolism also depends on leaf irradiance. Conclusions Under fruit shading only, the absence of a correlation between sugars and reduced AsA content indicated that fruit AsA content was not limited by leaf photosynthesis or sugar substrate, but strongly depended on fruit irradiance. Leaf shading most probably affected fruit AsA content by delaying fruit ripening, and suggested a complex regulation of AsA metabolism which depends on both fruit and leaf irradiance and fruit ripening stage. PMID:19033285

Influence of enamel composite thickness on value, chroma and translucency of a high and a nonhigh refractive index resin composite.

PubMed

Ferraris, Federico; Diamantopoulou, Sofia; Acunzo, Raffaele; Alcidi, Renato

2014-01-01

To evaluate the influence of thickness on the optical properties of two enamel shade composites, one with a high refractive index and one traditional. A medium value enamel shade was selected from the resin composites Enamel Plus HRi (UE2) and Enamel Plus HFO (GE2). Enamel Plus HRi is a high refractive index composite. Samples were fabricated in five different thicknesses: 0.3, 0.5, 1, 1.5 and 2 mm. Three specimens per material and thickness were fabricated. Three measurements per sample, over white, black and dentin composite background were generated with a spectrophotometer (Spectroshade Micro, MHT). Value, chroma, translucency and color differences (ΔE) of the specimens were calculated. RESULTS were analyzed by the Pearson correlation test, ANOVA and a post-hoc Tukey test. Increasing the thickness of the enamel layers decreased the translucency and the chroma of the substrate for both materials tested. For HRi the increase of the thickness resulted in an increase of the value, whereas for HFO it resulted in a reduction of the value. The two composites showed a significant difference in value for each thickness, but not in translucency and chroma. Color difference between them was perceptible in layers equal or higher than 0.5 mm. The high refractive index enamel (HRi) composite exhibits different optical behavior compared to the traditional one (HFO). HRi enamel composite behaves more like natural enamel as by increasing the thickness of the enamel layer, the value also increases.

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 shade colors. The results clearly show the benefit of automatic shade control strategies with integrated lighting control over a condition when shades are closed all day. The main contributor to the total energy savings is from lighting energy savings, followed by cooling energy savings. Shades provide greater benefit in a hot climate and in a moderate climate than in a cold climate. Different control strategies provide savings in the range of 7-35% for annual total space energy with higher savings with light colored shades. Control strategies of shades should be selected and optimized based on climate, orientation, window area, and window/shade properties. High performance glazings, when equipped with shades, show lower energy savings when compared to standard glazings. High transmittance/reflectance shades, such as white shades, perform better than dark shades in most of the cases due to higher lighting energy savings obtained with the automatic electric lighting control and the resulting cooling energy savings from rejection of some solar energy and a reduction in the heat from lights. A South orientation showed the least benefit of automatic control of shades when compare to other orientations due to the large fraction of time shades are required to provide visual comfort. Under automatic shade control, energy savings are higher the more often the shades can be raised. The different automatic control strategies present tradeoffs between energy savings and comfort. With regard to visual quality, daylight quality assessments on view, glare, luminance ratios, and UDI can be used to assess shade control strategies. Automatic shade control can increase the number of view hours while controlling sunlight penetration. With automatic shade control, more daylight hours can be provided within the beneficial range of 100-2000 lux compared to shades that are closed all day. For a person facing the window, discomfort glare is likely to increase the more often the shades are raised. Keeping the shades down ensures an acceptable glare condition, but limits energy savings. Luminance ratios are another metric that can be used to assess shade performance. With white shades, the luminance ratios between the task and proximate surfaces are improved. Dark shades help improve the luminance ratios between the task and distant surfaces. When the shades are left open, even with no direct sunlight in the space, task to window luminance ratios will often exceed 1:10.

Influence of growing altitude, shade and harvest period on quality and biochemical composition of Ethiopian specialty coffee.

PubMed

Tolessa, Kassaye; D'heer, Jolien; Duchateau, Luc; Boeckx, Pascal

2017-07-01

Coffee quality is a key characteristic for the international market, comprising cup quality and chemical bean constituents. In Ethiopia, using total specialty cup scores, coffees are grouped into Q1 (specialty 1) ≥ 85 and Q2 (80-84.75). This classification results in market segmentation and higher prices. Although different studies have evaluated the effects of altitude and shade on bean quality, optimum shade levels along different altitudinal ranges are not clearly indicated. Information on effects of harvest periods on coffee quality is also scanty. The present study examined the influences of these factors and their interactions on Ethiopian coffee quality RESULTS: Coffee from high altitude with open or medium shade and early to middle harvest periods had a superior bean quality. These growing conditions also favoured the production of beans with lower caffeine. An increasing altitude, from mid to high, at approximately 400 m, decreased caffeine content by 10%. At high altitude, dense shade decreased Q1 coffee by 50%. Compared to late harvesting, early harvesting increased the percentage from 27% to 73%. At mid altitude, > 80% is Q2 coffee. Changes of quality scores driven by altitude, shade and harvest period are small, although they may induce dramatic switches in the fraction Q1 versus Q2 coffee. The latter affects both farmers' profits and competitiveness in international markets. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

49 CFR 571.302 - Standard No. 302; Flammability of interior materials.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., head restraints, floor coverings, sun visors, curtains, shades, wheel housing covers, engine... seven to eight smooth, rounded teeth per 25 mm. S5.3Procedure. (a) Mount the specimen so that both sides...

Do sun- versus shade-grown kiwifruits perform differently upon storage? An overview of fruit maturity and nutraceutical properties of whole and fresh-cut produce.

PubMed

Landi, Marco; Tardelli, Francesca; Remorini, Damiano; Massai, Rossano; Guidi, Lucia

2014-05-14

Fresh-cut produce represents a good method to save about 25% of the kiwifruit not useful to meet the fresh fruit-marketing standard due to improper size and shape. For that reason, fresh-cut kiwifruit has been extensively studied. However, the comprehension of the influence of some aspects of cultivation might further increase the shelf life as well as the nutritional values of that fruit. This study explored the hypothesis that kiwifruits grown fully exposed to sunlight or partially shaded differently perform upon storage as whole fruit and as minimally processed produce. Flesh firmness (FF), total solids soluble (SSC), ascorbate (AAT), flavonoids (TFO), and phenols (TF) contents were evaluated in sliced and whole fruit upon 3 days of storage at 4 °C after 75 days of cold chamber storage at 0 °C. The activities of two enzymes related to the softening process, polygalacturonase (PG) and pectinmethylesterase (PME), were evaluated as well. FF and SSC were constitutively higher in sun-exposed fruit, and those characteristics remained higher during the storage as whole fruit. Greater constitutive content of AAT, TFO, and TP was found in sun-exposed whole fruit, although after cutting the reduction in their content was significantly lower in shaded fruits. PME and PG activities were higher only in whole shaded fruits, whereas no relevant differences occurred after cutting. In summary, sun-exposed fruits were more suitable for the fresh-fruit market, whereas the shaded counterpart displayed a good predisposition for use as fresh-cut produce, maintaining similar fruit maturity properties but higher nutraceutical values when sliced than fruit grown under full sun.

Tooth shade measurements under standard and nonstandard illumination and their agreement with skin color.

PubMed

Al-Dwairi, Ziad; Shaweesh, Ashraf; Kamkarfar, Sohrab; Kamkarfar, Shahrzad; Borzabadi-Farahani, Ali; Lynch, Edward

2014-01-01

The purpose of this study was to examine the relationship between skin color (shade) and tooth shade under standard and nonstandard illumination sources. Four hundred Jordanian participants (200 males, 200 females, 20 to 50 years of age) were studied. Skin colors were assessed and categorized using the L'Oreal and Revlon foundation shade guides (light, medium, dark). The Vita Pan Classical Shade Guide (VPCSG; Vident) and digital Vita EasyShade Intraoral Dental Spectrophotometer (VESIDS; Vident) were used to select shades in the middle thirds of maxillary central incisors; tooth shades were classified into four categories (highest, high, medium, low). Significant gender differences were observed for skin colors (P = .000) and tooth shade guide systems (P = .001 and .050 for VPCSG and VESIDS, respectively). The observed agreement was 100% and 93% for skin and tooth shade guides, respectively. The corresponding kappa statistic values were 1.00 and 0.79, respectively (substantial agreement, P < .001). The observed agreement between skin color and tooth shades (VPCSG and VESIDS) was approximately 50%. The digital tooth shade guide system can be a satisfactory substitute for classical tooth shade guides and clinical shade matching. There was only moderate agreement between skin color and tooth shade.

Randomized controlled trial to evaluate tooth stain reduction with nicotine replacement gum during a smoking cessation program.

PubMed

Whelton, Helen; Kingston, Rose; O'Mullane, Denis; Nilsson, Frederick

2012-06-13

In addition to its general and periodontal health effects smoking causes tooth staining. Smoking cessation support interventions with an added stain removal or tooth whitening effect may increase motivation to quit smoking. Oral health professionals are well placed to provide smoking cessation advice and support to patients. The objective of the present study was to evaluate the effect of Nicorette(®) Freshmint Gum used in a smoking cessation programme administered in a dental setting, on extrinsic stain and tooth shade among smokers. An evaluator-blinded, randomized, 12-week parallel-group controlled trial was conducted among 200 daily smokers motivated to quit smoking. Participants were randomised to use either the Nicorette(®) Freshmint Gum or Nicorette(®) Microtab (tablet). Tooth staining and shade were rated using the modified Lobene Stain Index and the Vita(®) Shade Guide at baseline, weeks 2, 6 and 12. To maintain consistency with other whitening studies, the primary end-point was the mean change in stain index between baseline and week 6. Secondary variables included changes in stain measurements and tooth shade at the other time points the number of gums or tablets used per day and throughout the trial period; and the number of cigarettes smoked per day. Treatments were compared using analysis of covariance (ANCOVA), using treatment and nicotine dependence as factors and the corresponding baseline measurement as a covariate. Each comparison (modified intention-to-treat) was tested at the 0.05 level, two-sided. Within-treatment changes from baseline were compared using a paired t-test. At week 6, the gum-group experienced a reduction in mean stain scores whilst the tablet-group experienced an increase with mean changes of -0.14 and +0.12 respectively, (p = 0.005, ANCOVA). The change in mean tooth shade scores was statistically significantly greater in the gum-group than in the tablet group at 2 (p = 0.015), 6 (p = 0.011) and 12 weeks (p = 0.003) with greater lightening in the gum-group at each examination period. These results support the efficacy of the tested nicotine replacement gum in stain reduction and shade lightening. These findings may help dentists to motivate those wishing to quit smoking using a nicotine replacement gum. NCT01440985.

Performative building envelope design correlated to solar radiation and cooling energy consumption

NASA Astrophysics Data System (ADS)

Jacky, Thiodore; Santoni

2017-11-01

Climate change as an ongoing anthropogenic environmental challenge is predominantly caused by an amplification in the amount of greenhouse gases (GHGs), notably carbon dioxide (CO2) in building sector. Global CO2 emissions are emitted from HVAC (Heating, Ventilation, and Air Conditioning) occupation to provide thermal comfort in building. In fact, the amount of energy used for cooling or heating building is implication of building envelope design. Building envelope acts as interface layer of heat transfer between outdoor environment and the interior of a building. It appears as wall, window, roof and external shading device. This paper examines performance of various design strategy on building envelope to limit solar radiation and reduce cooling loads in tropical climate. The design strategies are considering orientation, window to wall ratio, material properties, and external shading device. This research applied simulation method using Autodesk Ecotect to investigate simultaneously between variations of wall and window ratio, shading device composition and the implication to the amount of solar radiation, cooling energy consumption. Comparative analysis on the data will determine logical variation between opening and shading device composition and cooling energy consumption. Optimizing the building envelope design is crucial strategy for reducing CO2 emissions and long-term energy reduction in building sector. Simulation technology as feedback loop will lead to better performative building envelope.

Reduction of shading-derived artifacts in skin chromophore imaging without measurements or assumptions about the shape of the subject

NASA Astrophysics Data System (ADS)

Yoshida, Kenichiro; Nishidate, Izumi; Ojima, Nobutoshi; Iwata, Kayoko

2014-01-01

To quantitatively evaluate skin chromophores over a wide region of curved skin surface, we propose an approach that suppresses the effect of the shading-derived error in the reflectance on the estimation of chromophore concentrations, without sacrificing the accuracy of that estimation. In our method, we use multiple regression analysis, assuming the absorbance spectrum as the response variable and the extinction coefficients of melanin, oxygenated hemoglobin, and deoxygenated hemoglobin as the predictor variables. The concentrations of melanin and total hemoglobin are determined from the multiple regression coefficients using compensation formulae (CF) based on the diffuse reflectance spectra derived from a Monte Carlo simulation. To suppress the shading-derived error, we investigated three different combinations of multiple regression coefficients for the CF. In vivo measurements with the forearm skin demonstrated that the proposed approach can reduce the estimation errors that are due to shading-derived errors in the reflectance. With the best combination of multiple regression coefficients, we estimated that the ratio of the error to the chromophore concentrations is about 10%. The proposed method does not require any measurements or assumptions about the shape of the subjects; this is an advantage over other studies related to the reduction of shading-derived errors.

Efficacy of do-it-yourself whitening as compared to conventional tooth whitening modalities: an in vitro study.

PubMed

Kwon, S R; Meharry, M; Oyoyo, U; Li, Y

2015-01-01

To evaluate the efficacy of do-it-yourself (DIY) whitening as compared to conventional tooth whitening modalities using different shade assessment tools. Extracted human molars (120) were randomly distributed to six groups (n=20). Whitening was performed according to manufacturer's directions for over-the-counter, dentist-dispensed for home use, and in-office whitening. DIY whitening consisted of a strawberry and baking soda mix. Additionally, negative and positive controls were used. Two evaluators used the Vita Classical (VC) and Vita Bleachedguide 3D-Master with interpolated numbers (BGi) for visual assessment at baseline and one-week, one-month, and three-month postwhitening. Instrumental measurements were performed with a spectrophotometer. Kruskal-Wallis procedure was used to assess color changes among groups and intraclass correlation (ICC) to evaluate agreement between evaluators. DIY exhibited lower color change (ΔSGUVC, ΔSGUBGi, ΔE*, where SGU = shade guide unit and E = overall color change) compared to other whitening groups at all time points (p<0.05). ICC demonstrated very good agreement between evaluators with VC and BGi at each time point. Both shade guides were related with each other and strongly related to instrumental measurements (p<0.05). DIY whitening was the least effective whitening modality. Both VC and BGi are related with each other and have good correlation with instrumental measurements.

Deployable Debris Shields For Space Station

NASA Technical Reports Server (NTRS)

Christiansen, Eric L.; Cour-Palais, Burton G.; Crews, Jeanne

1993-01-01

Multilayer shields made of lightweight sheet materials deployed from proposed Space Station Freedom for additional protection against orbiting debris. Deployment mechanism attached at each location on exterior where extra protection needed. Equipment withdraws layer of material from storage in manner similar to unfurling sail or extending window shade. Number of layers deployed depends on required degree of protection, and could be as large as five.

Using microabrasive material to remove fluorosis stains.

PubMed

Allen, Kenneth; Agosta, Claudine; Estafan, Denise

2004-03-01

Increased public access to fluoride has decreased the prevalence of caries and increased the prevalence of fluorosis staining. This article provides a case report involving a conservative method of removing fluorosis stain, as well as describes an in vitro test of the method. A healthy man sought treatment at New York University College of Dentistry for removal of severe, dark brown fluorosis staining on his anterior teeth. To remove the stain, the treating clinician used a microabrasive material, which leaves enamel intact, instead of a tooth-whitening agent, which requires removal of all affected enamel. To demonstrate that enamel structure is not disturbed by the microabrasive material, the authors performed a study using scanning electron microscopy, or SEM. They viewed enamel structure under SEM at x1,000 magnification. They viewed untreated microabraded enamel and compared it with enamel that had been treated for 20 seconds with 37 percent phosphoric acid. An etch pattern was not discernible on the tooth treated with the microabrasive material. The enamel prisms remained intact and the cores were not exposed. Microabrasion removes intrinsic fluorosis stain effectively while protecting enamel. In this case, an enamel shade of brown not in the range of any tooth color shade guide was reduced.

EXAMINING THE PREFERENCE FOR SHADE STRUCTURES IN FARMED GREEN SEA TURTLES (CHELONIA MYDAS) AND SHADE'S EFFECT ON GROWTH AND TEMPERATURES.

PubMed

Keller, Martha; Mustin, Walter

2017-03-01

The Cayman Turtle Farm raises thousands of green sea turtles ( Chelonia mydas ) annually under aquaculture conditions. Historically, the turtles have been raised in tanks without routine access to a shade structure. The purpose of this study was to determine the effects of adding a shade structure on curved carapace length (CCL) and weight gain of green sea turtles. In addition, water and cloacal temperatures were compared across treatment groups and shade cover preferences observed. Ninety turtles were split equally into three treatment groups for this 8-wk study. In the first group turtles were kept in tanks in full sun, the second group in half-shaded tanks, and the third group in tanks completely covered with shade cloth. Time-lapse cameras mounted above half-shaded tanks were used to determine turtle shade structure preferences throughout the day. There were no differences in CCL among treatment groups. Significant increases in weights were noted in turtles kept in full sun and half-shaded tanks versus the fully shaded tanks. Significantly higher water and cloacal turtle temperatures were noted in the full-sun tank compared with the half-shaded or completely shaded tanks. A significantly lower number of turtles was observed in the sun in the half-shaded tanks, indicating a possible preference by turtles for a shade structure. Results suggest that providing shade structures for sea turtles results in a significant decrease in both overall water temperature as well as a reduction in maximum high daily temperatures. Results also suggest that turtles exhibit a preference for shade structures when it is provided as an option. From these results, we recommend that a shade structure be provided when housing green sea turtles in outdoor enclosures.

Optical properties of composite restorations influenced by dissimilar dentin restoratives.

PubMed

Marjanovic, Jovana; Veljovic, Djordje N; Stasic, Jovana N; Savic-Stankovic, Tatjana; Trifkovic, Branka; Miletic, Vesna

2018-05-01

To evaluate optical properties (color and translucency) of 'sandwich' restorations of resin-based composites and esthetically unfavorable dentin restoratives. Cylindrical 'dentin' specimens (8mm in diameter and 2mm thick, N=5/group) were prepared using EverX Posterior (GC), Biodentine (Septodont), experimental hydroxyapatite (HAP) or conventional composites (Gradia Direct Posterior, GC; Filtek Z250 and Filtek Z500, 3M ESPE). Capping 'enamel' layers were prepared using composites (Gradia Direct Posterior, Filtek Z250 or Z550) of A1 or A3 shade and the following thickness: 0.6, 1 or 2mm. Color (ΔE) and translucency parameter (TP) were determined using a spectrophotometer (VITA Easyshade Advance 4.0, VITA Zahnfabrik). Data were statistically analyzed using analysis of variance with Tukey's post-hoc tests (α=0.05). TP was greatly affected by layer thickness, whilst ΔE depended on shade and layer thickness of the capping composite. HAP and Biodentine showed significantly lower TP and higher ΔE (deviation from 'ideal white') than composites (p<0.05). Greater TP was seen in EverX_composite groups than in corresponding control groups of the same shade and thickness. TP of composites combined with Biodentine or HAP was below 2, lower than the corresponding control groups (p<0.05). Within-group differences of ΔE were greatest in HAP_composite groups. EverX_Gradia and EverX_FiltekZ250 combinations showed the most comparable ΔE with the control groups. A 2mm thick layer of composite covering dentin restoratives with unfavorable esthetics is recommended for a final 'sandwich' restoration that is esthetically comparable to a conventional, mono-composite control restoration. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

Rationale, Design, Samples, and Baseline Sun Protection in a Randomized Trial on a Skin Cancer Prevention Intervention in Resort Environments

PubMed Central

Buller, David B.; Andersen, Peter A.; Walkosz, Barbara J.; Scott, Michael D.; Beck, Larry; Cutter, Gary R.

2016-01-01

Introduction Exposure to solar ultraviolet radiation during recreation is a risk factor for skin cancer. A trial evaluating an intervention to promote advanced sun protection (sunscreen pre-application/reapplication; protective hats and clothing; use of shade) during vacations. Materials and Methods Adult visitors to hotels/resorts with outdoor recreation (i.e., vacationers) participated in a group-randomized pretest-posttest controlled quasi-experimental design in 2012–14. Hotels/resorts were pair-matched and randomly assigned to the intervention or untreated control group. Sun protection (e.g., clothing, hats, shade and sunscreen) was measured in cross-sectional samples by observation and a face-to-face intercept survey during two-day visits. Results Initially, 41 hotel/resorts (11%) participated but 4 dropped out before posttest. Hotel/resorts were diverse (employees=30 to 900; latitude=24o 78′ N to 50o 52′ N; elevation=2 ft. to 9,726 ft. above sea level), and had a variety of outdoor venues (beaches/pools, court/lawn games, golf courses, common areas, and chairlifts). At pretest, 4,347 vacationers were observed and 3,531 surveyed. More females were surveyed (61%) than observed (50%). Vacationers were mostly 35–60 years old, highly educated (college education = 68%) and non-Hispanic white (93%), with high-risk skin types (22%). Vacationers reported covering 60% of their skin with clothing. Also, 40% of vacationers used shade; 60% applied sunscreen; and 42% had been sunburned. Conclusions The trial faced challenges recruiting resorts but result show that the large, multi-state sample of vacationers were at high risk for solar UV exposure. PMID:26593781

The Effect of Luting Cement and Titanium Base on the Final Color of Zirconium Oxide Core Material.

PubMed

Capa, Nuray; Tuncel, Ilkin; Tak, Onjen; Usumez, Aslihan

2017-02-01

To evaluate the effects of different types of luting cements and different colors of zirconium cores on the final color of the restoration that simulates implant-supported fixed partial dentures (FPDs) by using a titanium base on the bottom. One hundred and twenty zirconium oxide core plates (Zr-Zahn; 10 mm in width, 5 mm in length, 0.5 mm in height) were prepared in different shades (n = 20; noncolored, A2, A3, B1, C2, D2). The specimens were subdivided into two subgroups for the two types of luting cements (n = 10). The initial color measurements were made on zirconium oxide core plates using a spectrometer. To create the cement thicknesses, stretch strips with holes in the middle (5 mm in diameter, 70 μm in height) were used. The second measurement was done on the zirconium oxide core plates after the application of the resin cement (U-200, A2 Shade) or polycarboxylate cement (Lumicon). The final measurement was done after placing the titanium discs (5 mm in diameter, 3 mm in height) in the bottom. The data were analyzed with two-way ANOVA and Tukey's honestly significant differences (HSD) tests (α = 0.05). The ∆E* ab value was higher in the resin cement-applied group than in the polycarboxylate cement-applied group (p < 0.001). The highest ∆E* ab value was recorded for the zirconium oxide core-resin cement-titanium base, and the lowest was recorded for the polycarboxylate cement-zirconium oxide core (p < 0.001). The luting cement, the presence of titanium, and the color of zirconium are all important factors that determine the final shade of zirconia cores in implant-supported FPDs. © 2015 by the American College of Prosthodontists.

Impacts of Trees on Urban Environment in the Contiguous United States

NASA Astrophysics Data System (ADS)

Wang, C.; Upreti, R.; Wang, Z.; Yang, J.

2017-12-01

Mounting empirical evidence shows that urban trees are effective in mitigating the thermal stress in the built environment, whereas large scale numerical simulations remain scarce. In this study, we evaluated the effects of shade trees on the built environment in terms of radiative cooling, pedestrian thermal comfort, and surface energy balance, carried out over the contiguous United States (CONUS). A coupled Weather Research and Forecasting-urban modeling system was adopted, incorporating exclusively the radiative shading effect of urban trees. Results show that on average the mean 2-m air temperature in urban areas decreases by 3.06 ˚C, and the 2-m relative humidity increases by 13.62% over the entire CONUS with the shading effect. Analysis of pedestrian thermal comfort shows that shade trees help to improve summer thermal comfort level, but could be detrimental in the winter for Northern cities. In addition, it was found that trees alter the surface energy balance by primarily enhancing the radiative cooling, leading to significant re-distribution of the sensible heat while leaving the ground heat storage comparatively intact.

The effect of variations in translucency and background on color differences in CAD/CAM lithium disilicate glass ceramics.

PubMed

Al Ben Ali, Abdulaziz; Kang, Kiho; Finkelman, Matthew D; Zandparsa, Roya; Hirayama, Hiroshi

2014-04-01

The purpose of this study was to compare the effect of variations in translucency and background on color differences (ΔE) for different shades of computer-aided design and computer-aided manufacturing (CAD/CAM) lithium disilicate glass ceramics. A pilot study suggested n = 10 as an appropriate sample size for the number of lithium disilicate glass ceramic cylinders per group. High-transparency (HT) and low-transparency (LT) cylinders (diameter, 12 mm; length, 13 mm) were fabricated in three ceramic shades (BL1, A2, C3) using CAD/CAM technology and were cut into specimen disks (thickness, 1.2 mm; diameter, 12 mm) for placement on Natural Die (ND1 and ND4) backgrounds. Four combinations of translucency and background color were evaluated in terms of color differences for the three ceramic shades: group 1 (HT ND1, reference), group 2 (HT ND4), group 3 (LT ND1), and group 4 (LT ND4). A spectrophotometer was used to measure the color differences. Nonparametric tests (Kruskal-Wallis tests) were used to evaluate the color differences among the tested groups, and Mann-Whitney U tests with Bonferroni correction were used as post hoc tests. Furthermore, for each ceramic shade, the HT groups were compared to the LT groups using the Mann-Whitney U test. Significant differences were present among the tested groups of the same ceramic shade (p < 0.001). The highest ΔE values were observed in the HT ND4 group for BL1, while the lowest ΔE values were found in the LT ND1 group for both A2 and C3. Further, the HT groups and the groups with a darker background (ND4) showed increased ΔE values compared with the other groups (p < 0.001). Within the limitations of this study, the results suggested that the translucency and background color significantly influenced the lithium disilicate glass ceramic color among the BL1, A2, and C3 ceramic shades. Changing the underlying color from a lighter background to a darker background resulted in increased color differences. © 2013 by the American College of Prosthodontists.

Sun shield

NASA Technical Reports Server (NTRS)

Frank, Arthur M. (Inventor); Derespinis, Silvio F. (Inventor); Mockovciak, John, Jr. (Inventor)

1987-01-01

A shading device which is capable of compactly storing a flexible shade on a biased, window shade type spring roller is disclosed. It is controlled to deliver the shade selectively to either its operative shading or compact storage orientation.

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

PubMed

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

2007-02-07

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

WE-G-207-07: Iterative CT Shading Correction Method with No Prior Information

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, P; Mao, T; Niu, T

2015-06-15

Purpose: Shading artifacts are caused by scatter contamination, beam hardening effects and other non-ideal imaging condition. Our Purpose is to propose a novel and general correction framework to eliminate low-frequency shading artifacts in CT imaging (e.g., cone-beam CT, low-kVp CT) without relying on prior information. Methods: Our method applies general knowledge of the relatively uniform CT number distribution in one tissue component. Image segmentation is applied to construct template image where each structure is filled with the same CT number of that specific tissue. By subtracting the ideal template from CT image, the residual from various error sources are generated.more » Since the forward projection is an integration process, the non-continuous low-frequency shading artifacts in the image become continuous and low-frequency signals in the line integral. Residual image is thus forward projected and its line integral is filtered using Savitzky-Golay filter to estimate the error. A compensation map is reconstructed on the error using standard FDK algorithm and added to the original image to obtain the shading corrected one. Since the segmentation is not accurate on shaded CT image, the proposed scheme is iterated until the variation of residual image is minimized. Results: The proposed method is evaluated on a Catphan600 phantom, a pelvic patient and a CT angiography scan for carotid artery assessment. Compared to the one without correction, our method reduces the overall CT number error from >200 HU to be <35 HU and increases the spatial uniformity by a factor of 1.4. Conclusion: We propose an effective iterative algorithm for shading correction in CT imaging. Being different from existing algorithms, our method is only assisted by general anatomical and physical information in CT imaging without relying on prior knowledge. Our method is thus practical and attractive as a general solution to CT shading correction. This work is supported by the National Science Foundation of China (NSFC Grant No. 81201091), National High Technology Research and Development Program of China (863 program, Grant No. 2015AA020917), and Fund Project for Excellent Abroad Scholar Personnel in Science and Technology.« less

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

PubMed

Kvalheim, S F; Øilo, M

2014-03-01

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

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.

Patients' perspective on dental aesthetics in a South-Eastern European community.

PubMed

Dudea, Diana; Lasserre, Jean-François; Alb, Camelia; Culic, Bogdan; Pop Ciutrila, Ioana Sofia; Colosi, Horatiu

2012-07-01

To assess the importance attributed to dental aesthetics by subjects from a Romanian community. In addition, the role played by dental color, the group-distributions based on the self-evaluation of dental color and the previous experience regarding whitening treatments are analysed. A multiple-choice questionnaire was administered to 540 patients in dental offices in Cluj-Napoca, Romania; the subjects were also asked to self-evaluate their dental shade, using a set of images as a comparison. Answers to the questionnaires were statistically analysed using Microsoft Excel and SPSS 13.00 (Pearson's chi-square test, Fisher's exact test, Kendall's tau b). From the participants, 17.96% were motivated by aesthetic reasons to ask for treatment; most of the patients evaluated their smile as "acceptable" (38.51%) or "having some defects" (29.44%) and were self-included in groups of medium and dark shades (33.7% and 33.89%, respectively). Whilst 22.40% of the subjects considered the dental color as being the most evident defect of their dentition, 39.07% indicated a self-perception of "an abnormal dental shade". A strong correlation between darker self-assessed tooth color-groups and the self-perception of an abnormal tooth color was found (Chi square p≪0.001, Kendall's tau-c=0.44, with p≪0.001). Previous whitening treatments were reported by 8.88% of the subjects. Among patients who wanted to improve one of their oral functions, the majority requested changes in aesthetics. Dental shade is one of the aspects recognized as problematic by the participants, but nonetheless the percentage of patients who had previously benefited by whitening treatments was moderate. Copyright © 2012 Elsevier Ltd. All rights reserved.

Influence of illuminants on the color distribution of shade guides.

PubMed

Park, Ji-Hoon; Lee, Yong-Keun; Lim, Bum-Soon

2006-12-01

Although a shade tab in a shade guide is matched to a natural tooth in the order of value, hue, and chroma, there are limited data on the color distribution of currently available shade guides sorted by these 3 parameters. Furthermore, spectrophotometric color measurements of shade tabs differ depending on the standard illuminant employed. The purpose of this study was to determine the color distributions of 2 shade guides in value (CIE L( *)), chroma (C( *)(ab)) and hue angle (h(o)) scale relative to the standard illuminants D(65), A, and F2. Color of shade tabs (n=36) from 2 shade guides (Vita Lumin and Chromascop) were measured, and the distributions for CIE L( *), C( *)(ab) and h(o) values were compared. Color differences of shade tabs depending on the illuminant were calculated. The distributions of the ratios of CIE L( *) and C( *)(ab) values of each shade tab compared with the lowest value tab or the lowest chroma tab were determined. The data for the value, chroma, and hue angle within each shade guide were analyzed with a 2-way ANOVA with the factors of shade designation and type of illuminant (alpha=.05). Color difference caused by change of illuminant was analyzed with a 2-way ANOVA with the factors of shade designation and pair of illuminants compared (alpha=.05). The Scheffe multiple comparison test was performed as a post hoc test. CIE L( *), C( *)(ab) and h(o) values were influenced by shade designation and type of illuminant in both shade guides. Color difference caused by change of the illuminant was influenced by the shade designation and pair of illuminants compared. The order of mean color differences of 16 Vita Lumin shade tabs by pairs of illuminants compared was as follows: DeltaE( *)(ab) (D(65)/F2) = 1.63 3.7). Color distribution of 2 shade guides by the value and chroma was not logical.

Effects of patch size and type of coffee matrix on ithomiine butterfly diversity and dispersal in cloud-forest fragments.

PubMed

Muriel, Sandra B; Kattan, Gustavo H

2009-08-01

Determining the permeability of different types of landscape matrices to animal movement is essential for conserving populations in fragmented landscapes. We evaluated the effects of habitat patch size and matrix type on diversity, isolation, and dispersal of ithomiine butterflies in forest fragments surrounded by coffee agroecosystems in the Colombian Andes. Because ithomiines prefer a shaded understory, we expected the highest diversity and abundance in large fragments surrounded by shade coffee and the lowest in small fragments surrounded by sun coffee. We also thought shade coffee would favor butterfly dispersal and immigration into forest patches. We marked 9675 butterflies of 39 species in 12 forest patches over a year. Microclimate conditions were more similar to the forest interior in the shade-coffee matrix than in the sun-coffee matrix, but patch size and matrix type did not affect species richness and abundance in forest fragments. Furthermore, age structure and temporal recruitment patterns of the butterfly community were similar in all fragments, independent of patch size or matrix type. There were no differences in the numbers of butterflies flying in the matrices at two distances from the forest patch, but their behavior differed. Flight in the sun-coffee matrix was rapid and directional, whereas butterflies in shade-coffee matrix flew slowly. Seven out of 130 recaptured butterflies immigrated into patches in the shade-coffee matrix, and one immigrated into a patch surrounded by sun coffee. Although the shade-coffee matrix facilitated movement in the landscape, sun-coffee matrix was not impermeable to butterflies. Ithomiines exhibited behavioral plasticity in habitat use and high mobility. These traits favor their persistence in heterogeneous landscapes, opening opportunities for their conservation. Understanding the dynamics and resource requirements of different organisms in rural landscapes is critical for identifying management options that address both animals' and farmers' needs.

AVIRIS spectral trajectories for forested areas of the Gifford Pinchot National Forest

NASA Technical Reports Server (NTRS)

Sabol, Donald E., Jr.; Smith, Milton O.; Adams, John B.; Zukin, Janet H.; Tucker, Compton J.; Roberts, Dar A.; Gillespie, Alan R.

1995-01-01

A simple mixing model employing reference endmembers (green vegetation, non-photosynthetic vegetation, soil and shade), and using 180 AVIRIS bands, was used to establish an interpretive framework for a forested area in the Pacific Northwest. A regrowth trend, based on changes in the endmember proportions, was defined for conifers that extends from clearcuts to mature forest, and by implication to old growth. Deciduous species within replanted forest plots caused the fractions to be displaced from the main coniferous regrowth trend and to move toward the green vegetation fraction. The results indicate that the spectral information in AVIRIS can be inverted to estimate approximate stand age and relative proportion of deciduous species in the context of the area studied. Using AVIRIS we measured a 3 to 5 percent increase in woody material in old-growth forest, as distinct from other mature forest. This result is consistent with a predicted increase in NPV in old-growth forest, based on field observations. Previous application of the mixing analysis to a TM image of the same area separated old growth based solely on the shade fraction; however the approach required successful removal of shade introduced by topography. Our new results suggest that with the high spectral resolution and high signal-to-noise of AVIRIS images it may be possible to characterize and map old-growth forests in the Northwest using both the NPV fraction and shade.

[Effects of light intensities after anthesis on the photosynthetic characteristics and chloroplast ultrastructure in mesophyll cell of summer maize (Zea mays L. )].

PubMed

Gao, Jia; Cui, Hai Yan; Shi, Jian Guo; Dong, Shu Ting; Liu, Peng; Zhao, Bin; Zhang, Ji Wang

2018-03-01

We examined the changes of photosynthetic characteristics and chloroplast ultrastructure in mesophyll cell of summer maize in response to different light intensities in the field, with the summer maize hybrid Denghai 605 as experimental material. Two treatments of both shading (S) and increasing light (L) from flowering to physiological maturity stage were designed, with the ambient sunlight treatment as control (CK). Under shading treatment, poorly developed thylakoid structure, blurry lamellar structure, loose granum, large gap between slices and warping granum were the major characteristics in chloroplast. Meanwhile, photosynthetic rate (P n ), transpiration rate, stomatal conductance, chlorophyll content, and actual photo-chemical efficiency (Φ PSII ) decreased, whereas the maximal photochemical efficiency and non-photochemical quenching increased, which resulted in decreases in grain yield under shading treatment. However, a better development was observed in chloroplasts for L treatment, with the number of grana and lamellae increased and lamellae arranged compactly. In addition, P n and Φ PSII increased under L treatment, which increased grain yield. The chloroplast arrangement dispersed in mesophyll cells and chloroplast ultrastructure was destroyed after shading, and then chlorophyll synthesis per unit leaf area and photosynthetic capacity decreased. In contrast, the number of grana and lamellae increased and lamellae arranged compactly after increasing light, which are beneficial for corn yield.

Color management of porcelain veneers: influence of dentin and resin cement colors.

PubMed

Dozic, Alma; Tsagkari, Maria; Khashayar, Ghazal; Aboushelib, Moustafa

2010-01-01

Porcelain veneers have become an interesting treatment option to correct the shape and color of anterior teeth. Because of their limited thickness and high translucency, achieving a good color match is influenced by several variables. The aim of this work was to investigate the influence of natural dentin and resin cement colors on final color match of porcelain veneers. A preselected shade tab (A1) was chosen as the target color for a maxillary central incisor, and its color parameters (L*a*b*) were measured using a digital spectrophotometer (SpectroShade, MHT). Nine natural dentin colors (Natural Die Material, Ivoclar Vivadent) representing a wide range of tooth colors were used to prepare resin replicas of the maxillary central incisor with a standard preparation for porcelain veneers. The prepared porcelain veneers (IPS Empress Esthetic, A1, 0.6 mm thick, Ivoclar Vivadent) were cemented on the resin dies (nine groups of natural dentin colors) using seven shades of resin cement (Variolink Veneers, Ivoclar Vivadent). The L*a*b* values of the cemented veneers were measured, and DE values were calculated against the preselected target color (A1). DE greater than 3.3 was considered as a significant color mismatch detectable by the human eye. The seven shades of resin cement had no significant influence on the final color of the veneers, as the measured DE values were almost identical for every test group. On the other hand, the color of natural dentin was a significant factor that influenced final color match. None of the 63 tested combinations (nine natural dentin colors and seven resin cement colors) produced an acceptable color match. Thin porcelain veneers cannot mask underlying tooth color even when different shades of resin cement are used. Incorporation of opaque porcelain (high chroma) may improve final color match.

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

USGS Publications Warehouse

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

2016-01-01

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

Shade improves survival rate of outplanted 2-0 red fir seedlings

Treesearch

Donald T. Gordon

1970-01-01

Effect of shade on 2-0 red fir seedlings outplanted on the Tahoe National Forest, central California, was studied by comparing five treatments: no shade, low shade for 1 year and for 2 years, and high shade for 1 year and for 2 years. Seedlings benefited from shading-even under apparently excellent survival conditions in the first season. The extra cost of artificial...

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

NASA Astrophysics Data System (ADS)

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

2018-05-01

Upland red rice (Oryza sativa) contains anthocyanin, a phenolic compounds that can act as antioxidants and functional food for human dietary. The content of functional food on upland red rice is influenced by shading condition, but the production is also influenced by environmental condition, especially the availability of light. The study aims is to assess and analyze the effect of shade on the growth and production of upland red rice. The research was conducted using the quantitative method to obtain the optimal shading condition that can increase the rice anthocyanin content and relatively high production. The research was arranged in split plot design, with shade as main plot and the different of cultivar as sub plot with three replications. The shading treatment consist of 4 levels as follows: n1=shade level < 25 %, n2=shade level 25-50%, n3=shade level 50-75% and n4=shade level > 75%. The cultivar tested were (v1) = Labandiri, (v2) = Jangkobembe, (v3) = Ranggohitam, and (v4) = Paedara. The rice planted in between teak wood trees with different age and level of canopy. The research reveals that shades had an effect in decreasing plant production (the higher level of shade, the higher the decrease level of production), but the shades can improve the quality of red rice through the increase of anthocyanin content.

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

PubMed

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

2017-03-01

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

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

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.

Light-scattering properties of a Venetian blind slat used for daylighting applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nilsson, Annica M.; Jonsson, Jacob C.

2010-12-15

The low cost, simplicity, and aesthetic appearance of external and internal shading devices, make them commonly used for daylighting and glare-control applications. Shading devices, such as Venetian blinds, screens, and roller shades, generally exhibit light scattering and/or light redirecting properties. This requires the bi-directional scattering distribution function (BSDF) of the material to be known in order to accurately predict the daylight distribution and energy flow through the fenestration system. Acquiring the complete BSDF is not a straightforward task, and to complete the process it is often required that a model is used to complement the measured data. In this project,more » a Venetian blind slat with a white top surface and a brushed aluminum bottom surface was optically characterized. A goniophotometer and an integrating sphere spectrophotometer were used to determine the angle resolved and hemispherical reflectance of the sample, respectively. The acquired data were fitted to a scattering model providing one Lambertian and one angle dependent description of the surface properties. These were used in combination with raytracing to obtain the complete BSDFs of the Venetian blind system. (author)« less

Responses of legumes and grasses to non-, moderate, and dense shade in Missouri, USA. I. Forage yield and its species-level plasticity

Treesearch

Kejia Pang; J.W. Van Sambeek; Nadia E. Navarrete-Tindall; Chung-Ho Lin; Shibu Jose; H. E. Garrett

2017-01-01

Annual screenings of forage grasses and legumes for shade tolerance were conducted from 1996 to 2001 in the outdoor Shade Tolerance Screening Laboratory at the Horticulture and Agroforestry Research Center, University of Missouri. Forty-three forages were grown under non-shade (100% of full sunlight), moderate shade (45%), and dense shade (20%) without competition for...

Consistency in color parameters of a commonly used shade guide.

PubMed

Tashkandi, Esam

2010-01-01

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

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?

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

PubMed

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

2016-01-01

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

Assessment of microclimate conditions under artificial shades in a ginseng field

PubMed Central

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

2015-01-01

Background Knowledge on microclimate conditions under artificial shades in a ginseng field would facilitate climate-aware management of ginseng production. Methods Weather data were measured under the shade and outside the shade at two fields located in Gochang-gun and Jeongeup-si, Korea, in 2011 and 2012 seasons to assess temperature and humidity conditions under the shade. An empirical approach was developed and validated for the estimation of leaf wetness duration (LWD) using weather measurements outside the shade as inputs to the model. Results Air temperature and relative humidity were similar between under the shade and outside the shade. For example, temperature conditions favorable for ginseng growth, e.g., between 8°C and 27°C, occurred slightly less frequently in hours during night times under the shade (91%) than outside (92%). Humidity conditions favorable for development of a foliar disease, e.g., relative humidity > 70%, occurred slightly more frequently under the shade (84%) than outside (82%). Effectiveness of correction schemes to an empirical LWD model differed by rainfall conditions for the estimation of LWD under the shade using weather measurements outside the shade as inputs to the model. During dew eligible days, a correction scheme to an empirical LWD model was slightly effective (10%) in reducing estimation errors under the shade. However, another correction approach during rainfall eligible days reduced errors of LWD estimation by 17%. Conclusion Weather measurements outside the shade and LWD estimates derived from these measurements would be useful as inputs for decision support systems to predict ginseng growth and disease development. PMID:26843827

Growth, photosynthetic pigments and production of essential oil of long-pepper under different light conditions.

PubMed

Lima, Vandimilli A; Pacheco, Fernanda V; Avelar, Rafaella P; Alvarenga, Ivan C A; Pinto, José Eduardo B P; Alvarenga, Amauri A DE

2017-01-01

Piper hispidinervum C. DC. is popularly known as long-pepper and it owns a commercial value due to the essential oil it produces. Long-pepper oil is rich in safrole and eugenoln components that have insecticidal, fungicidal and bactericidal activity. It has been establish that to medicinal plants light influences not only growth but also essential oil production. The growth, the content of photosynthetic pigments and the essential oil production of Piper hispidinervum at greenhouses with different light conditions was evaluated. The treatments were characterized by cultivation of plants for 180 days under different light conditions, produced by shading greenhouses with 50% and 30% of natural incident irradiance, two colored shading nets red (RN) and blue (BN) both blocking 50% of the incident radiation and one treatment at full-sun (0% of shade). The results showed that the treatments of 50% shade and RN and BN were the ones which stimulated the greater growth. Blue and red light also had the best production of photosynthetic pigments. Essential oil yielded more under full sun therefore this is the most indicated condition to produce seedlings for the chemical and pharmaceutical industry.

Reproductive success in varying light environments: direct and indirect effects of light on plants and pollinators.

PubMed

Kilkenny, Francis F; Galloway, Laura F

2008-03-01

Plant populations often exist in spatially heterogeneous environments. Light level can directly affect plant reproductive success through resource availability or by altering pollinator behavior. It can also indirectly influence reproductive success by determining floral display size which may in turn influence pollinator attraction. We evaluated direct and indirect effects of light availability and measured phenotypic selection on phenological traits that may enhance pollen receipt in the insect-pollinated herb Campanulastrum americanum. In a natural population, plants in the sun had larger displays and received 7 times more visits than plants in the shade. Using experimental arrays to separate the direct effects of irradiance on insects from their response to display size, we found more visits to plants in the sun than in the shade, but no association between number of visits each flower received and display size. Plants in the sun were not pollen limited but pollen-augmented shade flowers produced 50% more seeds than open-pollinated flowers. Phenological traits, which may influence pollen receipt, were not under direct selection in the sun. However, earlier initiation and a longer duration of flowering were favored in the shade, which may enhance visitation in this pollen-limited habitat.

Restoring warped document images through 3D shape modeling.

PubMed

Tan, Chew Lim; Zhang, Li; Zhang, Zheng; Xia, Tao

2006-02-01

Scanning a document page from a thick bound volume often results in two kinds of distortions in the scanned image, i.e., shade along the "spine" of the book and warping in the shade area. In this paper, we propose an efficient restoration method based on the discovery of the 3D shape of a book surface from the shading information in a scanned document image. From a technical point of view, this shape from shading (SFS) problem in real-world environments is characterized by 1) a proximal and moving light source, 2) Lambertian reflection, 3) nonuniform albedo distribution, and 4) document skew. Taking all these factors into account, we first build practical models (consisting of a 3D geometric model and a 3D optical model) for the practical scanning conditions to reconstruct the 3D shape of the book surface. We next restore the scanned document image using this shape based on deshading and dewarping models. Finally, we evaluate the restoration results by comparing our estimated surface shape with the real shape as well as the OCR performance on original and restored document images. The results show that the geometric and photometric distortions are mostly removed and the OCR results are improved markedly.

Shade-induced nuclear localization of PIF7 is regulated by phosphorylation and 14-3-3 proteins in Arabidopsis.

PubMed

Huang, Xu; Zhang, Qian; Jiang, Yupei; Yang, Chuanwei; Wang, Qianyue; Li, Lin

2018-06-21

Shade avoidance syndrome enables shaded plants to grow and compete effectively against their neighbors. In Arabidopsis , the shade-induced de-phosphorylation of the transcription factor PIF7 (PHYTOCHROME-INTERACTING FACTOR 7) is the key event linking light perception to stem elongation. However, the mechanism through which phosphorylation regulates the activity of PIF7 is unclear. Here, we show that shade light induces the de-phosphorylation and nuclear accumulation of PIF7. Phosphorylation-resistant site mutations in PIF7 result in increased nuclear localization and shade-induced gene expression, and consequently augment hypocotyl elongation. PIF7 interacts with 14-3-3 proteins. Blocking the interaction between PIF7 and 14-3-3 proteins or reducing the expression of 14-3-3 proteins accelerates shade-induced nuclear localization and de-phosphorylation of PIF7, and enhances the shade phenotype. By contrast, the 14-3-3 overexpressing line displays an attenuated shade phenotype. These studies demonstrate a phosphorylation-dependent translocation of PIF7 when plants are in shade and a novel mechanism involving 14-3-3 proteins, mediated by the retention of PIF7 in the cytoplasm that suppresses the shade response. © 2018, Huang et al.

Discoloration of the mucosa caused by different restorative materials - a spectrophotometric in vitro study.

PubMed

Ioannidis, Alexis; Cathomen, Elena; Jung, Ronald E; Fehmer, Vincent; Hüsler, Jürg; Thoma, Daniel S

2017-09-01

To evaluate the discoloration of the mucosa caused by different ceramic and metal-based materials. On six pig maxillae, trap-door flaps were prepared bilaterally. Different ceramic and metal-based specimens were placed underneath the flap. To simulate increasing mucosal thicknesses (MC), connective tissue grafts (CTGs) were harvested. Spectrophotometric measurements were performed prior to flap elevation (T BL ) and for each material under the flap alone (1 mm MC) (T MC1 ), with a 1-mm CTG (2-mm MC) (T MC2 ) and with a 2-mm CTG (3-mm MC) (T MC3 ). Tested materials were as follows: Zr1 (zirconia), Zr2 (zirconia + pink ceramic), Zr3 (zirconia), Zr4 (fluorescent zirconia), Zr5 (zirconia), Zr6 (high translucent zirconia), Zr7 (low translucent zirconia) and Zr8 (low translucent zirconia), Gol (gold alloy), Ti1 (titanium alloy), Ti2 (anodized gold-shaded titanium alloy) and Ti3 (anodized pink-shaded titanium alloy). Color differences (ΔE) were calculated comparing the measurement of the native tissue (T BL ) and the measurements with varying mucosal thicknesses (T MC1-3 ). For ceramic materials, the median ΔE values for the different time-point comparison ranged as follows: 3.80 (Zr4) - 7.47 (Zr2) (pooled); 3.15 (Zr4) - 8.13 (Zr2) (T BL -T MC1 ); 3.39 (Zr4) - 7.24 (Zr2) (T BL -T MC2 ); 4.31 (Zr8) - 6.99 (Zr2) (T BL -T MC3 ). For metal-based materials, the median ΔE values were as follows: 4.20 (Gol) - 5.82 (Ti3) (pooled); 3.21 (Gol) - 13.56 (Ti1) (T BL -T CM1 ); 4.0 (Ti1) - 5.27 (Gol) (T BL -T CM2 ); 3.11 (Ti1) - 5.11 (Gol) (T BL -T CM2 ). The comparison of the materials and the time points showed in the nonparametric linear mixed model a significant interaction effect between material and time point (P < 0.001). The side was not a significant main effect, nor as term in an interaction with the other two effects. Reconstructive materials result in an evident discoloration of the mucosal tissue, tending to decrease with increasing mucosal thickness. The use of fluorescent zirconia (ceramic materials) or gold alloy (metal-based materials) lead to the least discoloration. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

A clinical evaluation of bleaching using whitening wraps and strips.

PubMed

Matis, Bruce A; Cochran, Michael; Wang, Ge; Franco, Miguel; Eckert, George J; Carlotti, Ronald J; Bryan, Christopher

2005-01-01

This study evaluated the degree of color change of teeth and the sensitivities of teeth and gums in an in vivo study. Ranir Whitening Wraps (WW2) and Crest Whitestrips Premium (WP2) were used twice a day and Ranir Whitening Wraps (WW1) were used once a day. Color evaluations occurred at baseline, after five and seven-day use of bleaching agent and 14 days post-bleaching. Color change was evaluated objectively and subjectively. Sensitivity evaluations were also accomplished. Seventy-six of the 78 subjects enrolled completed the study. All three products significantly lightened teeth. WW2 lightened more than WP2 and WW1 in L*, a*, b*, E and shade guide value. WP2 lightened more than WW1 in a*, b*, E and shade guide value. There was no difference in tooth sensitivity, but WW1 and WP2 caused less gingival sensitivity than WW2. The mean age of smokers was seven years younger than nonsmokers who qualified.

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.

Comparison of stabilities in translucency, fluorescence and opalescence of direct and indirect composite resins.

PubMed

Yu, Bin; Lee, Young-Keun

2013-01-01

To evaluate translucency, fluorescence and opalescence stabilities of direct and indirect composite resins after aging. One direct (16 shades) and two indirect composite resins (16 and 26 shades) were investigated. Resins were filled in a mold (1 mm thick) and light cured; post-curings were performed for indirect resins. Color was measured before and after 5,000 cycles of thermocycling on a reflection spectrophotometer in reflectance and transmittance modes to calculate parameters for translucency (TP), fluorescence (FL) and opalescence (OP). Differences in the changes of TP, FL and OP after aging by the type of resin were determined by t test, and those were also determined by one-way ANOVA with the factor of the brand or the shade group (P < 0.05). Changes in TP, FL and OP were -1.2 to 0.7, -0.2 to 0.4 and -0.6 to 1.3, respectively, for direct resins; and were -2.0 to 1.8, -0.9 to 0.4 and -2.9 to 3.7, respectively, for indirect resins. Changes in TP were not significantly different by the type of resin, but those in FL and OP were different (P = 0.05). Changes in optical parameters were influenced by the brand or the shade group of the resins (P < 0.05). Stabilities in optical properties of resins varied depending on type, brand or shade group. Aging significantly affected fluorescence and opalescence, but not translucency, of indirect resins compared to those of direct resins.

Shade tree spatial structure and pod production explain frosty pod rot intensity in cacao agroforests, Costa Rica.

PubMed

Gidoin, Cynthia; Avelino, Jacques; Deheuvels, Olivier; Cilas, Christian; Bieng, Marie Ange Ngo

2014-03-01

Vegetation composition and plant spatial structure affect disease intensity through resource and microclimatic variation effects. The aim of this study was to evaluate the independent effect and relative importance of host composition and plant spatial structure variables in explaining disease intensity at the plot scale. For that purpose, frosty pod rot intensity, a disease caused by Moniliophthora roreri on cacao pods, was monitored in 36 cacao agroforests in Costa Rica in order to assess the vegetation composition and spatial structure variables conducive to the disease. Hierarchical partitioning was used to identify the most causal factors. Firstly, pod production, cacao tree density and shade tree spatial structure had significant independent effects on disease intensity. In our case study, the amount of susceptible tissue was the most relevant host composition variable for explaining disease intensity by resource dilution. Indeed, cacao tree density probably affected disease intensity more by the creation of self-shading rather than by host dilution. Lastly, only regularly distributed forest trees, and not aggregated or randomly distributed forest trees, reduced disease intensity in comparison to plots with a low forest tree density. A regular spatial structure is probably crucial to the creation of moderate and uniform shade as recommended for frosty pod rot management. As pod production is an important service expected from these agroforests, shade tree spatial structure may be a lever for integrated management of frosty pod rot in cacao agroforests.

Genotype x shade effects for western hemlock.

Treesearch

G.R. Johnson; C. Cartwright

2005-01-01

Western hemlock (Tsuga heterophylla (Raf.) Sarg.) families were grown under different levels of shade for 2 or 3 years at two nursery sites to determine whether families performed differently relative to one another in the different shade environments. Differences were found both for levels of shade and families, but no family x shade interaction...

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

[Response of photosynthetic characteristics of peanut seedlings leaves to low light].

PubMed

Zhang, Kun; Wan, Yong-shan; Liu, Feng-zhen; Zhang, Er-qun; Wang, Su

2009-12-01

To investigate the effects of shading and light recovery on the photosynthetic characteristics of peanut seedlings leaves, different shading treatments including no shading, 27% shading, 43% shading, and 77% shading were performed with black sunshade net at the seedling stage of two peanut cultivars Fenghua 1 and Fenghua 2, with related parameters determined. It was shown that with the increase of shading degree, the leaf chlorophyll content, actual PSII photochemical efficiency under irradiance (phi(PS II)), and maximum PS II photochemical efficiency (Fv/Fm) of test cultivars increased, while the Chl a/b ratio and photosynthetic rate (Pn) decreased. On the first day after light recovery, the Pn and stomatal conductance (Gs) decreased while the intercellular CO2 concentration (Ci) increased with increasing shading degree when measured under high light, but the Pn increased and the Gs and Ci decreased with increasing shading degree when measured under low light. The ratio of Pn measured under low light to that measured under high light increased significantly. With increasing shading degree, the light compensation point, light saturation point, CO2 compensation point, CO2 saturation point, and carboxylation efficiency decreased, while the apparent quantum yield increased. After the removal of shading, the Pn, phi(PS II), and Fv/Fm under natural light decreased immediately, but increased gradually 3-5 days after. 15 days after light recovery, the Pn, phi(PS II) and Fv/Fm in treatment 27% shading recovered to the level of no shading. As for the other treatments, the restored extent differed with shading degree and test variety. In the same treatments, the leaf chlorophyll content, Pn and phi(PS II) of Fenghua 1 were higher than those of Fenghua 2. The results demonstrated that shading at seedling stage improved the capabilities of test varieties in using low light, but reduced the capabilities in using high light.

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

PubMed

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

2016-01-01

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

[Clinical application of IPS-empress 2 pressable all-ceramic crowns].

PubMed

Wang, Ai-jun; He, Xiao-ming; Liu, Li-xia; Zhang, Chao-biao; Zhang, Min; Shen, Bei-yong

2007-02-01

To evaluate the clinical prosthetic effect of IPS-Empress 2 pressahie ceramic crowns. 198 teeth of 70 patients were restored with IPS-Empress 2 pressahie ceramic crowns. The patients were asked to return in one week and every half year. The clinical prosthetic effect was evaluated. Through follow-up of 3-38 months, the veneer porcelain crowns of 3 teeth were broken. 2 crowns fall off due to teeth fracture, gingivitis occurred in 2 teeth, pulpitis or periapical periodontitis occurred in 3 teeth. The shades of 3 crowns were darkening. The prosthetic effect of 185 teeth was satisfied. The rate of satisfaction was 93.4%. IPS-Empress 2 pressable all-ceramic crown has the advantages of aesthetic effect, good hiocompatihility and simple fabrication. But its strength is not enough for posterior teeth and it can not cover the deep color of non-vital teeth and metal materials.

The effect of shade on the container index and pupal productivity of the mosquitoes Aedes aegypti and Culex pipiens breeding in artificial containers.

PubMed

Vezzani, D; Albicócco, A P

2009-03-01

The aim of this study was to assess whether certain attributes of larval breeding sites are correlated with pupal productivity (i.e. numbers of pupae collected per sampling period), so that these could be used as the focus for control measures to enhance control efficiency. Therefore, the objectives were to identify the months of highest pupal productivity of Aedes aegypti (L.) and Culex pipiens L. (Diptera: Culicidae) in an urban temperate cemetery in Argentina where artificial containers of < 6 L (flower vases) were the predominant breeding habitats, to compare various measures of the productivity of sunlit and shaded containers and to determine whether the composition of the containers affected pupal productivity. Over a period of 9 months, 200 randomly chosen water-filled containers (100 sunlit and 100 shaded), out of approximately 3738 containers present (approximately 54% in shade), were examined each month within a cemetery (5 ha) in Buenos Aires (October 2006 to June 2007). In total, 3440 immatures of Cx pipiens and 1974 of Ae. aegypti were collected. The larvae : pupae ratio was 10 times greater for the former, indicating that larval mortality was greater for Cx pipiens. Both mosquito species showed a higher container index (CI) in shaded than in sunlit containers (Ae. aegypti: 12.8% vs. 6.9% [chi(2) = 17.6, P < 0.001]; Cx pipiens: 6.3% vs. 1.8% [chi(2) = 24, P < 0.001]). However, the number and the density of immatures per infested container and the number of pupae per pupa-positive container did not differ significantly between sunlit and shaded containers for either species. Therefore, the overall relative productivity of pupae per ha of Ae. aegypti and Cx pipiens was 2.3 and 1.8 times greater, respectively, in shaded than in sunlit areas as a result of the greater CIs of containers in shaded areas. Neither the CI nor the number of immatures per infested container differed significantly among container types of different materials in either lighting condition. The maximum CI and total pupal counts occurred in March for Ae. aegypti and in January and February for Cx pipiens. The estimated peak abundance of pupae in the whole cemetery reached a total of approximately 4388 in the middle of March for Ae. aegypti and approximately 1059 in the middle of January for Cx pipiens. Spearman's correlations between monthly total productivity and monthly CI were significant at P < 0.001 for Ae. aegypti (r(s) = 0.975) and P < 0.01 for Cx pipiens (r(s) = 0.869). Our findings indicate that the efficacy of control campaigns against the two most important mosquito vectors in temperate Argentina could be improved by targeting containers in shaded areas, with maximum effort during species-specific times of year when pupal productivity is at its peak.

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.

The Effect of Surface Treatment on the Knoop Hardness of DICOR

DTIC Science & Technology

1990-01-01

during an AFIT- sponsored program in Dental Materials. 17. COSATI CODES 18. SUBJECT TERMS (Continue on reverse if necessary and Identify by block number...state of DICOR and harder than human enamel. Shaded DICOR had a surface hardness comparable to dental porcelain. The internal glass-ceramic material...THE EFFECT OF SURFACE TREATMENT ON THE KNOOP HARDNESS OF DICOR W.Patrick Naylor, DDS, MPH, MS* Lieutenant Colonel, US Air Force Dental Corps Brooks

Impacts of Topographic Shading on Surface Energy Balance of High Mountain Asia Glaciers

NASA Astrophysics Data System (ADS)

Olson, M.; Rupper, S.

2016-12-01

Topographic shading plays an important role in the energy balance of valley glaciers. While previous studies incorporate shading of varying complexity in surface energy balance models, to date, no large-scale studies have explored in depth the effects of topographic shading on glacier surface energy balance, and how these vary geographically within High Mountain Asia (HMA). Here we develop a model to examine the variability in potential insolation during the summer melt season using the ASTER GDEM and multi-hour solar geometry to simulate topographic shading on an idealized glacier. Shading is calculated in simulations utilizing a range of slopes, aspects, and latitudes. We test glacier mass balance sensitivity to these parameters for a suite of glaciers throughout HMA. Our results show that shading impacts on glaciers in HMA are highly variable across different geographic regions, but that they are largely predictable based on topographic characteristics such as slope and aspect. For example, we find in regions with steep topography and high relief that shading frequently dominates in the ablation zone rather than the accumulation zone, contrary to the findings of some previous studies. In these regions, topographic shading may play a more significant role in glacier energy balance. These results will better define the effects of topographic shading on surface energy balance, and improve model accuracy within HMA. Additionally, this topographic shading model provides a framework to quantify how shading effects vary for advancing or retreating glaciers as they respond to fluctuations in climate across HMA.

Shade selection performed by novice dental professionals and colorimeter.

PubMed

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

2006-01-01

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

Shade avoidance components and pathways in adult plants revealed by phenotypic profiling.

PubMed

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

2015-04-01

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.

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

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 Central

Brouwer, Bastiaan; Gardeström, Per; Keech, Olivier

2014-01-01

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. PMID:24604733

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.

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

PubMed Central

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

2016-01-01

Background and Objectives: This in vitro study compared the shade matching abilities of an intraoral spectrophotometer and the conventional visual method using two shade guides. The results of previous investigations between color perceived by human observers and color assessed by instruments have been inconclusive. The objectives were to determine accuracies and interrater agreement of both methods and effectiveness of two shade guides with either method. Methods: In the visual method, 10 examiners with normal color vision matched target control shade tabs taken from the two shade guides (VITAPAN Classical™ and VITAPAN 3D Master™) with other full sets of the respective shade guides. Each tab was matched 3 times to determine repeatability of visual examiners. The spectrophotometric shade matching was performed by two independent examiners using an intraoral spectrophotometer (VITA Easyshade™) with five repetitions for each tab. Results: Results revealed that visual method had greater accuracy than the spectrophotometer. The spectrophotometer; however, exhibited significantly better interrater agreement as compared to the visual method. While VITAPAN Classical shade guide was more accurate with the spectrophotometer, VITAPAN 3D Master shade guide proved better with visual method. Conclusion: This in vitro study clearly delineates the advantages and limitations of both methods. There were significant differences between the methods with the visual method producing more accurate results than the spectrophotometric method. The spectrophotometer showed far better interrater agreement scores irrespective of the shade guide used. Even though visual shade matching is subjective, it is not inferior and should not be underrated. Judicious combination of both techniques is imperative to attain a successful and esthetic outcome. PMID:27746599

Influence of background/surrounding area on accuracy of visual color matching.

PubMed

Dudea, Diana; Gasparik, Cristina; Botos, Alexandra; Alb, Florin; Irimie, Ada; Paravina, Rade D

2016-07-01

Visual shade selection is subjective and influenced by factors that might be operator-dependent or not. The objective was to evaluate influence of observer nonrelated factors (background/surrounding area, and light) and observer-related factors (gender and color competence) on shade-matching quality and to identify the most often mismatched shades in correlation with the background. Ten observers with average or superior color discrimination competence according to ISO TR 28642:2011 were asked to match 48 shade tabs of three VITA Classical shade guides, in a viewing booth under two light sources: D65 and D50. Gray, white, black, red, and light blue background/surrounding area simulated various clinical situations. The results were statistically analyzed using Kruskal-Wallis test and Mann-Whitney U test. Post hoc power analyses and sample size calculations were also conducted. The matching scores ranged between 72.7 % (using blue background) and 85.9 % (using white and black backgrounds). There was a statistically significant difference between matching scores on the five backgrounds (χ (2)(4) = 12.67, p = 0.01). When neutral gray was used as reference, Mann-Whitney U value was statistically significant only for the blue background (U = 107.00, Z = -2.52, p = 0.01). The influence of gender and lighting condition was also assessed, no statistically significance being found, but in both cases, the effect size and the achieved power were small. However, color discrimination competence did influence the results (p < 0.01). Background influenced shade matching results for tabs A3, B3, B4, and D4. Within the limitations of this study, it was concluded that 1. When it comes to the influence of the background/surround area on quality of color matching, no difference among achromatic backgrounds was recorded. Significantly worse results were recorded when the blue background was used. 2. Observers with superior color matching competence performed significantly better than the ones with average competence 3. The most frequently mismatched shade tabs were A3.5, B3, B4, and D4.

A clinical evaluation comparing two H2O2 concentrations used with a light-assisted chairside tooth whitening system.

PubMed

Ward, Marilyn; Felix, Heather

2012-04-01

The purpose of this study was to assess the efficacy of two different BriteSmile hydrogen peroxide (H2O2) gels in a split-arch protocol for whitening teeth in a clinical setting when used in conjunction with a BriteSmile BS4000 lamp. Fifteen subjects were enrolled into a single-center clinical trial. The efficacy of the BriteSmile BS4000 lamp using both 15% H2O2 and 25% H2O2 gel formulations was tested. Study subjects were concurrently exposed to the whitening lamp with the 15% H2O2 gel placed on half of their anterior teeth and the 25% H2O2 gel on the other half for a total light and gel exposure of 60 minutes. The clinical data collected were shade score, gingival health, and dentinal hypersensitivity self-assessment. Changes in tooth shade were better for subjects exposed to the 25% gel and the dental whitening lamp (average 8.0 shade changes) compared to subjects exposed to the 15% gel and dental whitening lamp (average 7.6 shade changes) immediately after treatment. The same held true at the 7-day follow-up (25% gel average 7.4 shade changes versus 15% gel average 7.3 shade changes). However, these differences were not statistically significant. No reports of irritation of gingival soft tissues were documented. The relative changes in mean sensitivity scores were similar for both groups with no significant differences in mean sensitivity scores between the groups. Both concentrations of H2O2 gel and the whitening lamp combined gave study subjects an average of 8.0 (25% gel) and 7.6 (15% gel) shade changes immediately after treatment. The 7-day follow-up examination resulted in a regression of lightest to an average of 7.4 (25% gel) and 7.3 (15% gel). It was concluded that the use of the chairside whitening light and either 15% or 25% hydrogen peroxide gel is safe and effective for whitening teeth in 1 hour.

Increased growth of young citrus trees under reduced radiation load in a semi-arid climate.

PubMed

Raveh, E; Cohen, S; Raz, T; Yakir, D; Grava, A; Goldschmidt, E E

2003-01-01

This study investigated the effects of radiation heat-load reduction by shading on the growth and development of citrus trees in a warm subtropical region. The experiment was conducted from mid-June until late October when daily maximal air temperature averaged 29.3 degrees C. Two-year-old de-fruited Murcott tangor (Citrus reticulata BlancoxCitrus sinensis (L.) Osb.) trees were grown under 30% or 60% shade tunnels, or 60% flat shade (providing midday shade only), using highly reflective aluminized nets. Non-shaded trees were used as the control. Shading reduced direct more than diffuse radiation. Daily radiation was reduced by 35% for the 30% Tunnel and 60% Flat treatments, and by 55% for the 60% Tunnel. Two days of intensive measurement showed that shading increased average sunlit leaf conductance by 44% and photosynthesis by 29%. Shading did not significantly influence root and stem dry weight growth, but it increased the increment in leaf dry weight during the three month period by an average of 28% relative to the control, while final tree height in the 30% Tunnel treatment exceeded the control by 35%. Shoot to root and shoot mass ratios increased and root mass ratio decreased due to shading because of the increase in leaf dry weight. Shading increased starch concentration in leaves while the shadiest treatment, 60% Tunnel, decreased starch concentration in the roots. Carbon isotope ratio (delta(13)C) of exposed leaves that developed under shading was significantly reduced by 1.9 per thousand in the 60% Tunnel, indicating that shading increased CO(2) concentrations at the chloroplasts (C(c)), as would be expected from increased conductance. Substomatal CO(2) concentrations, C(i), computed from leaf net CO(2) assimilation rate and conductance values, also indicate that shading increases internal CO(2) concentrations. Based on tree dry mass, tree height, and total carbohydrates fractions, the 30% Tunnel and the 60% Flat were the optimal shade treatments.

Partial shading of lateral branches affects growth, and foliage nitrogen- and water-use efficiencies in the conifer Cunninghamia lanceolata growing in a warm monsoon climate.

PubMed

Dong, Tingfa; Li, Junyu; Zhang, Yuanbin; Korpelainen, Helena; Niinemets, Ülo; Li, Chunyang

2015-06-01

The degree to which branches are autonomous in their acclimation responses to alteration in light environment is still poorly understood. We investigated the effects of shading of the sapling crown of Cunninghamia lanceolata (Lamb.) Hook on the whole-tree and mid-crown branch growth and current-year foliage structure and physiology. Four treatments providing 0, 50, 75 and 90% shading compared with full daylight (denoted as Treatment(0), Treatment(50%), Treatment(75%) and Treatment(90%), and Shaded(0), Shaded(50%), Shaded(75%) and Shaded(90%) for the shaded branches and Sunlit(0), Sunlit(50%), Sunlit(75%) and Sunlit(90%) for the opposite sunlit branches under natural light conditions, respectively), were applied over two consecutive growing seasons. Shading treatments decreased the growth of basal stem diameter, leaf dry mass per unit leaf area, stomatal conductance, transpiration rate, the ratio of water-soluble to structural leaf nitrogen content, photosynthetic nitrogen-use efficiency and instantaneous and long-term (estimated from carbon isotope composition) water-use efficiency in shaded branches. Differences between shaded and sunlit branches increased with increasing severity and duration of shading. A non-autonomous, partly compensatory behavior of non-shaded branches was observed for most traits, thus reflecting the dependence between the traits of sunlit branches and the severity of shading of the opposite crown half. The results collectively indicated that tree growth and branch and leaf acclimation responses of C. lanceolata are not only affected by the local light environment, but also by relative within-crown light conditions. We argue that such a non-autonomous branch response to changes in light conditions can improve whole-tree resource optimization. These results contribute to better understanding of tree growth and utilization of water and nitrogen under heterogeneous light conditions within tree canopies. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

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

Treesearch

Geoffery H. Donovan; David R. Butry

2009-01-01

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

Determination of the solar transmittance for the translucent shutter with PCM in liquid and solid state

NASA Astrophysics Data System (ADS)

Komerska, Anna; Ksionek, Dariusz; Rosiński, Marian

2017-11-01

This article presents results of the energy performance of an external translucent shading component integrated with a phase change material. A proposed technology is able to accumulate considerable amounts of energy in the latent heat by absorbing solar energy. Due to selective optical properties, much of the visible light is still transmitted through the facade. Experimental measurements were carried out in a laboratory set-up - testing thermal chamber, located in the Faculty of Building Services, Hydro and Environmental Engineering at Warsaw University of Technology. The main result of the experimental study was the evaluation of the average solar transmittance in the whole measured spectrum, as well as in the infrared and visible light. Since the shift in optical properties was observed when the material was undergoing a phase transition, the average spectral transmittances were measured for different states of matter of the PCM material. The tested shutter showed abilities to reduce and modulate daylight and solar heat gains in the indoor environment, which could contribute to considerable energy savings.

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

[Effects of shading in summer and autumn on physiological and biochemical characteristics of 'Huangjinya' in Shandong Province, China].

PubMed

Tian, Yue Yue; Zhang, Li Xia; Zhang, Zheng Qun; Qiao, Ming Ming; Fan, Yan Gen

2017-03-18

In order to ensure the suitable shade model for 'Huangjinya' tea plant in Shandong Province, black or blue shading net at 55%, 70% or 85% shading rates was selected to recover tea garden in summer and autumn, then micro-climate of tea garden, leaf color, chlorophyll fluorescence parameters, growth status and biochemical composition of tea shoots were investigated.The results showed that compared with the control, light intensity and air temperature in tea garden, leaf temperature of tea plants in different shading treatments significantly decreased, while air humidity in tea garden increased. The contents of chlorophyll in the tea leaves were obviously increased with increasing the shading rate, which resulted in the leaf color becoming green. The yellowing characteristics and biochemical quality of 'Huangjinya' tea plants could be well kept in 55% shading treatments. In 70% shading treatments, 'Huangjinya' tea plants had better growth situation and higher yield with no photo-inhibition. Compared with the blue shading treatments, black shading treatments could obviously promote the growth of 'Huangjinya' tea plants, keep yellowing characteristics, and improve the quality. Therefore, the 70% black shading treatment (daily PAR values of 1.2-3.5 ten thousand lx) was appropriate for promoting the growth of 'Huangjinya' tea plants at the seedling stage. For mature tea plants, the 55% black shading treatment (daily PAR values of 1.8-5.5 ten thousand lx) could be used to keep the yellowing characteristics and to improve biochemical quality effectively, so as to give full play to its variety characteristics, to achieve goal of high quality and high yield.

Effects of shading on plant growth, flower quality and photosynthetic capacity of Rosa hybrida

NASA Astrophysics Data System (ADS)

Hou, Wei; Luo, Ya; Wang, Xiaorong; Chen, Qing; Sun, Bo; Wang, Yan; Liu, Zejing; Tang, Haoru; Zhang, Yong

2018-04-01

With the acceleration of the urbanization process, numbers of garden plants are grown in shaded environment. Rose (Rosa hybrida) is one of the most important ornamental plants used in urban green spaces. In the present study, effects of shading on plant growth, flower quality and photosynthetic capacity of R. hybrida were investigated. The results showed that shade not only delayed the initial flowering date, but also prolonged the flowering time. The physiological indices, including flower fresh weight, total anthocyanins and flavonoids contents, were lower in plants grown with shade compared with those grown in sun exposure. Overall, R. hybrida seemed to be a shade adapted plant which could be successfully grown in urban green spaces or understory with slight shade.

Influence of season and microclimate on fertility of dairy cows in a hot-arid environment

NASA Astrophysics Data System (ADS)

Ray, D. E.; Jassim, A. H.; Armstrong, D. V.; Wiersma, F.; Schuh, J. D.

1992-09-01

Records were obtained over a 3 year period from six Holstein dairy farms of 300 to 500 cows each in the Phoenix, Ariz. area. Dairies were selected on the basis of similar management practices, herd size, milk production and facilities (with the exception of cooling systems). Microclimatic modifications (two dairies each) were shade only (approximately 3.7 m2/cow), evaporative-cooled shades and low-pressure water foggers under the shades. Data were categorized by season of calving (spring, Feb. May; summer, June Sept.; and fall, Oct. Jan.). Traits evaluated were calving interval, days open and services/conception. Calving interval was shortest for cows calving in the spring (378 days), intermediate in fall (382 days) and longest in summer (396 days). Similar seasonal trends were observed for days open (103, 103 and 119 days, respectively) and services/conception (1.54, 1.81 and 1.93, respectively). All differences between spring and summer were significant ( P < 0.05). Calving interval and days open were less for evaporative-cooled groups (374 and 98 days, respectively), with no difference between shade only and foggers (391 and 392 days, 112 and 116 days, respectively). Services/conception were similar for all groups (1.72 to 1.79). A significant interaction between microclimate and season for services/conception could be interpreted as (i) smaller season differences for evaporative-cooled groups than for shade or foggers, or (ii) a change in the ranking of control and fogger groups during summer versus fall. Evaporative cooling was more effective than fogging for reducing the detrimental effects of seasonal high temperatures on fertility.

Ensemble composition and activity levels of insectivorous bats in response to management intensification in coffee agroforestry systems.

PubMed

Williams-Guillén, Kimberly; Perfecto, Ivette

2011-01-26

Shade coffee plantations have received attention for their role in biodiversity conservation. Bats are among the most diverse mammalian taxa in these systems; however, previous studies of bats in coffee plantations have focused on the largely herbivorous leaf-nosed bats (Phyllostomidae). In contrast, we have virtually no information on how ensembles of aerial insectivorous bats--nearly half the Neotropical bat species--change in response to habitat modification. To evaluate the effects of agroecosystem management on insectivorous bats, we studied their diversity and activity in southern Chiapas, Mexico, a landscape dominated by coffee agroforestry. We used acoustic monitoring and live captures to characterize the insectivorous bat ensemble in forest fragments and coffee plantations differing in the structural and taxonomic complexity of shade trees. We captured bats of 12 non-phyllostomid species; acoustic monitoring revealed the presence of at least 12 more species of aerial insectivores. Richness of forest bats was the same across all land-use types; in contrast, species richness of open-space bats increased in low shade, intensively managed coffee plantations. Conversely, only forest bats demonstrated significant differences in ensemble structure (as measured by similarity indices) across land-use types. Both overall activity and feeding activity of forest bats declined significantly with increasing management intensity, while the overall activity, but not feeding activity, of open-space bats increased. We conclude that diverse shade coffee plantations in our study area serve as valuable foraging and commuting habitat for aerial insectivorous bats, and several species also commute through or forage in low shade coffee monocultures.

Preliminary design of a solar heat receiver for a Brayton cycle space power system

NASA Technical Reports Server (NTRS)

Cameron, H. M.; Mueller, L. A.; Namkoong, D.

1972-01-01

The preliminary design of a solar heat receiver for use as a heat source for an earth-orbiting 11-kWe Brayton-cycle engine is described. The result was a cavity heat receiver having the shape of a frustum of a cone. The wall of the cone is formed by 48 heat-transfer tubes, each tube containing pockets of lithium fluoride for storing heat for as much as 38 minutes of fullpower operation in the shade. Doors are provided in order to dump excess heat especially during operation in orbits with full sun exposure. The receiver material is predominantly columbium - 1-percent-zironium (Cb-1Zr) alloy. Full-scale testing of three heat-transfer tubes for more than 2000 hours and 1250 sun-shade cycles verified the design concept.

Green vegetation, nonphotosynthetic vegetation, and soils in AVIRIS data

NASA Technical Reports Server (NTRS)

Roberts, D. A.; Smith, M. O.; Adams, J. B.

1993-01-01

The problem of distinguishing between green vegetation, nonphotosynthetic vegetation (NPV, such as dry grass, leaf litter, and woody material), and soils in imaging-spectrometer data is addressed by analyzing an image taken by the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) over the Jasper Ridge Biological Preserve (California) on September 20, 1989, using spectral mixture analysis. Over 98 percent of the spectral variation could be explained by linear mixtures of three endmembers, green vegetation, shade, and soil. NPV, which could not be distinguished from soil when included as an endmember, was discriminated by residual spectra that contained cellulose and lignin absorptions. Distinct communities of green vegetation were distinguished by (1) nonlinear mixing effect caused by transmission and scattering by green leaves, (2) variations in a derived canopy-shade spectrum, and (3) the fraction of NPV.

The Importance of Insects in Energy Transfers Across Riparian Ecotones Along Hong Kong Streams

NASA Astrophysics Data System (ADS)

Chan, E. K.; Dudgeon, D.

2005-05-01

Energy and materials in the form of insects transfer reciprocally between land and water through stream riparian ecotones, and may provide important energy subsidies to aquatic and terrestrial consumers. Variation in the magnitude and extent of this transfer was investigated in 2004-05 in six Hong Kong streams: four shaded and two unshaded. A combination of pan traps and light traps were used to investigate seasonal activity of aquatic and terrestrial insects. Both were more abundant during the wet season (April to September). Over 80% of emerging aquatic insects stayed within 20 m of the stream bank at all sites, suggesting that the water to land subsidy was spatially restricted. Inputs of terrestrial insects into shaded streams were 30% greater than at open sites, and drift-feeding Parazacco spilurus (Cyprinidae) ate more terrestrial insects in shaded (>40% of prey) than unshaded streams (25% of prey). Stable isotope analysis (SIA; C & N) of potential prey and fish tissues confirmed the dietary importance of terrestrial insects. The spider Leucauge celebesiana (Tetragnathidae) builds orb web parallel to the water surface during the main period of aquatic insect emergence, and SIA indicated that aquatic insects were the primary prey of this terrestrial consumer.

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.

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.

Water and coffee: a systems approach to improving coffee harvesting work in Nicaragua.

PubMed

Silverstein, Barbara A; Bao, Stephen S; Russell, Steven; Stewart, Kate

2012-12-01

The aim of this study was to reduce the physical load on coffee-harvesting workers while maintaining productivity. Coffee is second to oil in commodity trading. Water is becoming scarce worldwide. The global virtual water footprint for one cup of coffee is 140 liters. Shade-grown coffee is one approach to reducing the water footprint. A participatory ergonomics approach was used during two Nicaraguan shade-grown coffee harvesting seasons to reduce the physical load on harvesters with the use of a newly designed bag instead of a basket strapped around the waist. Productivity in the mountainous, shade-grown coffee farms was maintained while physical load on the worker was improved somewhat.Among basket users, 84.2% reported pain in at least one body area compared with 78.9% of bag users (ns). Nonetheless, 74% of participants liked the bag "much better" than the basket. Workers identified ways the bag could be improved further with the use of local materials.These suggestions included (a) reducing the horizontal distance of the bag to reduce reach and (b) having waterproof material on the bag between the worker and the bag to reduce moisture and damage to the berries.There was no difference in productivity between using the bag and using the small basket. Workers are extending this participatory approach to how to get the harvested coffee cherries down the mountain other than carrying 40-kg bags on their backs. The ultimate goal is to make the coffee-harvesting bag design available to harvesters around the world.

Effect of ceramic thickness and shade on mechanical properties of a resin luting agent.

PubMed

Passos, Sheila Pestana; Kimpara, Estevão Tomomitsu; Bottino, Marco Antonio; Rizkalla, Amin S; Santos, Gildo Coelho

2014-08-01

This study aimed to investigate the influence of ceramic thickness and shade on the Knoop hardness and dynamic elastic modulus of a dual-cured resin cement. Six ceramic shades (Bleaching, A1, A2, A3, A3.5, B3) and two ceramic thicknesses (1 mm, 3 mm) were evaluated. Disk specimens (diameter: 7 mm; thickness: 2 mm) of the resin cement were light cured under a ceramic block. Light-cured specimens without the ceramic block at distances of 1 and 3 mm were also produced. The Knoop hardness number (KHN), density, and dynamic Young's moduli were determined. Statistical analysis was conducted using ANOVA and a Tukey B rank order test (p = 0.05). The bleaching 1-mm-thick group exhibited significantly higher dynamic Young's modulus. Lower dynamic Young's moduli were observed for the 3-mm-thick ceramic groups compared to bleaching 3-mm-thick group, and no difference was found among the other 3-mm groups. For the KHN, when A3.5 3-mm-thick was used, the KHN was significantly lower than bleaching and A1 1-mm-thick ceramic; however, no difference was exhibited between the thicknesses of the same shade. The dual-cured resin cement studied irradiated through the 1-mm-thick ceramic with the lightest shade (bleaching ceramic) exhibited a better elastic modulus, and there was no effect in KHN of the resin cement when light cured under different ceramic shades and thicknesses (1 and 3 mm), except when the A3.5 3-mm-thick ceramic was used. Variolink II irradiated through ceramic with the lowest chroma exhibited the highest elastic modulus; therefore, the light activation method might not be the same for all clinical situations. © 2014 by the American College of Prosthodontists.

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; ...

2015-05-29

Here, 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 US 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 shadingmore » 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.« less

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Eleanor; Pang, Xiufeng; McNeil, Andrew

Here, 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 US 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 shadingmore » 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.« less

Free range hens use the range more when the outdoor environment is enriched.

PubMed

Nagle, T A D; Glatz, P C

2012-04-01

To evaluate the role of using forage, shade and shelterbelts in attracting birds into the range, three trials were undertaken with free range layers both on a research facility and on commercial farms. Each of the trials on the free range research facility in South Australia used a total of 120 laying hens (Hyline Brown). Birds were housed in an eco-shelter which had 6 internal pens of equal size with a free range area adjoining the shelter. The on-farm trials were undertaken on commercial free range layer farms in the Darling Downs in Southeast Queensland with bird numbers on farms ranging from 2,000-6,800 hens. The first research trial examined the role of shaded areas in the range; the second trial examined the role of forage and the third trial examined the influence of shelterbelts in the range. These treatments were compared to a free range area with no enrichment. Aggressive feather pecking was only observed on a few occasions in all of the trials due to the low bird numbers housed. Enriching the free range environment attracted more birds into the range. Shaded areas were used by 18% of the hens with a tendency (p = 0.07) for more hens to be in the paddock. When forage was provided in paddocks more control birds (55%) were observed in the range in morning than in the afternoon (30%) while for the forage treatments 45% of the birds were in the range both during the morning and afternoon. When shelterbelts were provided there was a significantly (p<0.05) higher % of birds in the range (43% vs. 24%) and greater numbers of birds were observed in areas further away from the poultry house. The results from the on-farm trials mirrored the research trials. Overall 3 times more hens used the shaded areas than the non shaded areas, with slightly more using the shade in the morning than in the afternoon. As the environmental temperature increased the number of birds using the outdoor shade also increased. Overall 17 times more hens used the shelterbelt areas than the control areas, with slightly more using the shelterbelts in the afternoon than in the morning. Approximately 17 times more birds used the forage areas compared to the control area in the corresponding range. There were 8 times more birds using a hay bale enriched area compared to the area with no hay bales. The use of forage sources (including hay bales) were the most successful method on-farm to attract birds into the range followed by shelterbelts and artificial shade. Free range egg farmers are encouraged to provide pasture, shaded areas and shelterbelts to attract birds into the free range.

Intra- and interspecific variability of carbon isotope composition (d13C) and water-use efficiency in 5 deciduous tree species growing a mixed stand in North-Eastern France

NASA Astrophysics Data System (ADS)

Zapater, M.; Breda, N.; Storchi, G.; Granier, A.

2005-12-01

Intra and interspecific variability in leaf gas exchange (net assimilation, stomatal conductance, transpiration, water use efficiency: WUE), in carbon isotope composition (d13C) and leaf characteristics related to photosynthesis was assessed in 5 trees species growing in a young broad-leaved mixed forest in North-Eastern France (Hesse, Lorraine). The studied species belong to contrasted functional groups of light tolerance: European beech (Fagus sylvatica) as shade tolerant species; sessile oak (Quercus petraea) and hornbeam (Carpinus betulus) as semitolerant species; silver birch (Betula pendula) and European aspen (Populus tremula) as shade intolerant species (pioneer species). Gas exchange was measured at leaf level in the upper and the lower canopy layers using a portable system (LI-6200, Licor). d13C signatures were determined in the sun and shade leaves in both bulk material and soluble sugars. Clear differences in bulk leaves and soluble sugars d13C and intrinsic WUEint were found among the investigated species, whatever the leaf location in the canopy. Within each tree species, shade leaves exhibited lower WUEint and more negative d13C than sun leaves. Little variability among trees was found for a given species. The 3 functional groups were separated by their leaf carbon content. Nevertheless each of the variables d13C, leaf mass area and nitrogen content, alone, could not separate the groups. A linear relationship was found between WUEint and d13C at the intraspecific level (r2 = 0.87 for leaves; r2 =0.89 for sugars) and at the interspecific level (r2 = 0.72 for bulk leaves). Nevertheless, this relationship differed from that of Farquhar et al. (1982), due to a different intercept, while the slope was the same. The causes of these variations are discussed. Key words: d13C; deciduous; mixed forest; WUEint; shade tolerance.

Plant Pigment Identification: A Classroom and Outreach Activity

ERIC Educational Resources Information Center

Garber, Kathleen C. A.; Odendaal, Antoinette Y.; Carlson, Erin E.

2013-01-01

Anthocyanins are a class of pigments responsible for the bright colors of many flowers, fruits, and vegetables typically resulting in shades of red, blue, and purple. Students were asked to perform an activity to enable them to identify which anthocyanin was present in one of several possible plant materials through a hands-on activity. Students…

In vivo tooth-color measurement with a new 3D intraoral scanning system in comparison to conventional digital and visual color determination methods.

PubMed

Mehl, Albert; Bosch, Gabriel; Fischer, Carolin; Ender, Andreas

Three-dimensional (3D) intraoral scanning systems allow for the simultaneous acquisition of 3D information about tooth surfaces and a photorealistic view of the patient's tooth colors. The goal of this study was the in vivo comparison of a new 3D scanner with a color acquisition mode and conventional visual and digital color measurements. The colors of 40 teeth of 20 patients were evaluated in seven ways: 1) By dentists using the Vita 3D-Master; 2) By dental technicians using the Vita 3D-Master; 3) With the 3Shape Trios device; 4) With the Vita Easyshade device; 5) With the Vita Easyshade Advance device; 6) With the SpectroShade device; and 7) With the SpectroShade Micro device. Digital measurements of Groups 3 to 7 were repeated three times for each tooth. For all groups, both the CIE Lab values and the Vita 3D-Master values were recorded. The repeatability and relative accuracy of the Vita 3D-Master values were analyzed statistically using Pearson's chi-squared test (α < 0.05). ΔE values were calculated from the CIE Lab values, which served as a basis for performing multidimensional scaling (MDS) and evaluating differences between the groups using the one-way ANOVA with post hoc Tamhane's test (α < 0.05). The results of the ΔE values showed that clinically relevant differences between the evaluation by dentists, dental technicians, and the intraoral scanning device (3Shape) are negligible. The intraoral 3D scanning device (Group 3) and the digital systems (Groups 4 to 7) did not differ significantly in the repeatability of color shade management. The SpectroShade Micro (Group 7) had significantly better relative accuracy than the other devices. The results demonstrate that intraoral scanning systems can be used to measure both tooth color and tooth surface in 3D. Intraoral optical scanning devices allow for the acquisition of accurate 3D surface data. Tooth color can be evaluated simultaneously and can be used to determine the color of restorations without requiring additional conventional color-measurement methods.

Identifying outdoor thermal risk areas and evaluation of future thermal comfort concerning shading orientation in a traditional settlement.

PubMed

Huang, Kuo-Tsang; Yang, Shing-Ru; Matzarakis, Andreas; Lin, Tzu-Ping

2018-06-01

The outdoor thermal environment is expected to be deteriorated under climate change. An approach of risk identification including assessment from aspects of thermal stress effect, people's exposure, and local's vulnerability were adopted to study a hot-and-humid traditional rural community located at Tainan, Taiwan. Layers of each aspect were either constructed by in-situ measurements or simulations. To evaluate the future thermal comfort changes by simulations, the prerequisite hourly climate data of three future time slices were produced. Prognostic simulation model, ENVI-met, in combination with diagnostic model, RayMan, were respectively used for identifying current spatial distribution of thermal stress and for assessing the future thermal comfort changes. High thermal risk area was identified by superimposing layers of hazard, exposure and vulnerability. It revealed that because of the tourists' vulnerability to adapt local climate and the inflexibleness of choosing visiting time, it exhibited a high thermal stress at the Main Courtyard where its thermal comfort conditions will be deteriorated due to climate change. Furthermore, the thermal comfort conditions in various shading orientation were analyzed based on the changing climate in three future time slices, i.e. 2011-2040, 2041-2070, and 2071-2100. The results show the area with shading in the East and West side is more comfort than in the North side. In hot season, shading in the West side contributes less PET increasing, especially in the afternoon period. The severest overheat problem (the physiological equivalent temperature, PET>40°C) at the Main Courtyard will increase from current 10% to 28% in 2071-2100 in terms of overheating occurrence frequency. The results of this study can be used as the guidelines for environment analysis before planning or redesign community. Copyright © 2018 Elsevier B.V. All rights reserved.

In vivo and in vitro assessment of an intraoral dental colorimeter.

PubMed

Karaagaclioglu, Lale; Terzioglu, Hakan; Yilmaz, Burak; Yurdukoru, Bengul

2010-06-01

The purpose of this study was to assess the performance of an intraoral dental colorimeter. In vivo repeatability of an intraoral colorimeter was assessed by performing color measurements of 30 individuals' right maxillary central incisor. Three consecutive measurements from each individual were made. In the in vitro part of the study, 25 metal-ceramic and 25 all-ceramic specimens were prepared. Five shades of metal-ceramic and all-ceramic specimens were selected for color determination. A widely recognized in vitro colorimeter was used as the control group for the in vitro performance assessment of the in vivo colorimeter. The color differentiation capability of two colorimeters was compared with the readings obtained from ceramic specimens. DeltaE values between shade groups of ceramic specimens were calculated and statistically analyzed with Student's t-test. The repeatability of the intraoral instrument was evaluated statistically with Intraclass correlation coefficient. The in vivo evaluation results showed that the overall repeatability coefficient values of L*, a*, and b* notations of the intraoral colorimeter were "excellent." The color differences (DeltaE) calculated between the colorimeters were significant only between shades A(1)-B(1) for metal-ceramic specimens (p= 0.002); however, from 5 of 10 shade couples of all-ceramic specimens, the color differences obtained from the readings of the in vivo colorimeter were significantly different from that of the in vitro colorimeter (p < 0.001). For all specimens, the differences between DeltaE values were within clinically acceptable limits (<3.5). Within the limitations of this study, the intraoral colorimeter exhibited successful in vivo repeatability; however, the color difference detection performance of the device varied depending on the translucency of the specimens.

Numerical study of the vertical shading devices effect on the thermal performance of promotional apartments in hot dry climate of Algeria

NASA Astrophysics Data System (ADS)

Berkouk, Djihed; Bouzir, Tallal Abdel Karim; Mazouz, Said

2018-05-01

The bioclimatic architecture considers the local climatic conditions in order to reconcile maximally the comfort condition of the occupants. Through the several simulations effectuated by the TRNSYS software, this paper shows that the new architecture produced in the south of Algeria following the northern cities tendency is not fully adapted to the hot dry climate of the southern regions, such as the city of Biskra. In these regions, the passive techniques design influence strongly on the thermal architectural space performance. In this regard, diverse of the vertical shading devices size were proposed to evaluate the impact of this passive technique on the thermal performance of the promotional apartments situated in the city of Biskra. The comparative analysis between the simulation results says that the effectiveness of the vertical shading devices on the thermal performance spaces is reducing the indoor air temperature during the summer period. In addition, this analysis shows that promotional apartments are unsuitable for the desert climate.

Evaluation of Cellular Shades in the PNNL Lab Homes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Petersen, Joseph M.; Sullivan, Greg; Cort, Katherine A.

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

SU-D-206-04: Iterative CBCT Scatter Shading Correction Without Prior Information

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bai, Y; Wu, P; Mao, T

2016-06-15

Purpose: To estimate and remove the scatter contamination in the acquired projection of cone-beam CT (CBCT), to suppress the shading artifacts and improve the image quality without prior information. Methods: The uncorrected CBCT images containing shading artifacts are reconstructed by applying the standard FDK algorithm on CBCT raw projections. The uncorrected image is then segmented to generate an initial template image. To estimate scatter signal, the differences are calculated by subtracting the simulated projections of the template image from the raw projections. Since scatter signals are dominantly continuous and low-frequency in the projection domain, they are estimated by low-pass filteringmore » the difference signals and subtracted from the raw CBCT projections to achieve the scatter correction. Finally, the corrected CBCT image is reconstructed from the corrected projection data. Since an accurate template image is not readily segmented from the uncorrected CBCT image, the proposed scheme is iterated until the produced template is not altered. Results: The proposed scheme is evaluated on the Catphan©600 phantom data and CBCT images acquired from a pelvis patient. The result shows that shading artifacts have been effectively suppressed by the proposed method. Using multi-detector CT (MDCT) images as reference, quantitative analysis is operated to measure the quality of corrected images. Compared to images without correction, the method proposed reduces the overall CT number error from over 200 HU to be less than 50 HU and can increase the spatial uniformity. Conclusion: An iterative strategy without relying on the prior information is proposed in this work to remove the shading artifacts due to scatter contamination in the projection domain. The method is evaluated in phantom and patient studies and the result shows that the image quality is remarkably improved. The proposed method is efficient and practical to address the poor image quality issue of CBCT images. This work is supported by the Zhejiang Provincial Natural Science Foundation of China (Grant No. LR16F010001), National High-tech R&D Program for Young Scientists by the Ministry of Science and Technology of China (Grant No. 2015AA020917).« less

External shading devices for energy efficient building

NASA Astrophysics Data System (ADS)

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

2018-02-01

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

Numerical analysis of air-flow and temperature field in a passenger car compartment

NASA Astrophysics Data System (ADS)

Kamar, Haslinda Mohamed; Kamsah, Nazri; Mohammad Nor, Ahmad Miski

2012-06-01

This paper presents a numerical study on the temperature field inside a passenger's compartment of a Proton Wira saloon car using computational fluid dynamics (CFD) method. The main goal is to investigate the effects of different glazing types applied onto the front and rear windscreens of the car on the distribution of air-temperature inside the passenger compartment in the steady-state conditions. The air-flow condition in the passenger's compartment is also investigated. Fluent CFD software was used to develop a three-dimensional symmetrical model of the passenger's compartment. Simplified representations of the driver and one rear passenger were incorporated into the CFD model of the passenger's compartment. Two types of glazing were considered namely clear insulated laminated tint (CIL) with a shading coefficient of 0.78 and green insulated laminate tint (GIL) with a shading coefficient of 0.5. Results of the CFD analysis were compared with those obtained when the windscreens are made up of clear glass having a shading coefficient of 0.86. Results of the CFD analysis show that for a given glazing material, the temperature of the air around the driver is slightly lower than the air around the rear passenger. Also, the use of GIL glazing material on both the front and rear windscreens significantly reduces the air temperature inside the passenger's compartment of the car. This contributes to a better thermal comfort condition to the occupants. Swirling air flow condition occurs in the passenger compartment. The air-flow intensity and velocity are higher along the side wall of the passenger's compartment compared to that along the middle section of the compartment. It was also found that the use of glazing materials on both the front and rear windscreen has no significant effects on the air-flow condition inside the passenger's compartment of the car.

Relationship between natural tooth shade and skin colour.

PubMed

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

2013-06-01

The purpose of this study was to assess the correlation of skin colour and tooth shade. One hundred and twenty six individuals aging between 18 to 25 years participated in this study. Colour of the maxillary central incisors was examined by VITA easy shade. Tooth shades were assigned to four ordinal values. Nivea Beauty Protect Foundation shade sample was used as a guide to assess facial skin colour Shin colours were also assigned to four ordinal values. Spearman test revealed that there was a significant relationship between tooth shade and skin colour Total co-relation factor was 51.6% (p <0 .01). Co-relation factors were 57% for women and 27% for men (p <0 .01). The highest tooth shade prevalence belonged to the second group and the highest skin colour prevalence was also in the second skin colour group.

Measured and estimated performance of a fleet of shaded photovoltaic systems with string and module-level inverters

DOE PAGES

MacAlpine, Sara; Deline, Chris; Dobos, Aron

2017-03-16

Shade obstructions can significantly impact the performance of photovoltaic (PV) systems. Although there are many models for partially shaded PV arrays, there is a lack of information available regarding their accuracy and uncertainty when compared with actual field performance. This work assesses the recorded performance of 46 residential PV systems, equipped with either string-level or module-level inverters, under a variety of shading conditions. We compare their energy production data to annual PV performance predictions, with a focus on the practical models developed here for National Renewable Energy Laboratory's system advisor model software. This includes assessment of shade extent on eachmore » PV system by using traditional onsite surveys and newer 3D obstruction modelling. The electrical impact of shade is modelled by either a nonlinear performance model or assumption of linear impact with shade extent, depending on the inverter type. When applied to the fleet of residential PV systems, performance is predicted with median annual bias errors of 2.5% or less, for systems with up to 20% estimated shading loss. The partial shade models are not found to add appreciable uncertainty to annual predictions of energy production for this fleet of systems but do introduce a monthly root-mean-square error of approximately 4%-9% due to seasonal effects. Here the use of a detailed 3D model results in similar or improved accuracy over site survey methods, indicating that, with proper description of shade obstructions, modelling of partially shaded PV arrays can be done completely remotely, potentially saving time and cost.« less

Conservation in Brazil's Chocolate Forest: The Unlikely Persistence of the Traditional Cocoa Agroecosystem.

PubMed

JOHNS

1999-01-01

/ In southern Bahia, Brazil, the traditional cocoa agroecosystem with a dense shade canopy of native trees is now recognized as a secondary conservation route for highly endangered Atlantic Rainforest species. This "chocolate forest" of the densely shaded farms persists despite a massive 20-year Brazilian government modernization program in which shade was seen as a chief impediment to raising cocoa production. The objective of this study was to determine how this traditional agroecosystem endured. Although dense shade limits cocoa yield, it provides several agroecological benefits: control of insect pests and weeds, microclimate stability, and soil fertility maintenance. A keycomponent of modernization efforts was a shade-tree removal program designed to maximize cocoa production by using low shade and fertilizer while substituting agrochemicals for many beneficial roles of the overhead trees. This research found that many farmers rejected, or only partially accepted, the shade reduction process although it promised much higher cocoa yield and profit. Farmers employing a wide range of shading were interviewed, and it was found that decisions to remove or maintain the shade trees were linked to both agroecological and risk-minimization factors. Farmers' perceptions of the agroecological functions of the shade trees and individual willingness to entertain the economic risk associated with substituting agrochemicals for these were important. A less-profitable, but lower-risk approach of occasional fertilizer and agrochemical use with the traditional shade intact was a rational and widespread choice. Policies designed to maintain the traditional agroecosystem through the current economic crisis should heed the multiple functions of the overhead trees. KEY WORDS: Conservation; Brazil; Atlantic Rainforest; Cocoa; Agroecology; Risk; Agroforestry

Detecting Subtle Shifts in Ecosystem Functioning in a Dynamic Estuarine Environment

PubMed Central

Pratt, Daniel R.; Lohrer, Andrew M.; Thrush, Simon F.; Hewitt, Judi E.; Townsend, Michael; Cartner, Katie; Pilditch, Conrad A.; Harris, Rachel J.; van Colen, Carl; Rodil, Iván F.

2015-01-01

Identifying the effects of stressors before they impact ecosystem functioning can be challenging in dynamic, heterogeneous ‘real-world’ ecosystems. In aquatic systems, for example, reductions in water clarity can limit the light available for photosynthesis, with knock-on consequences for secondary consumers, though in naturally turbid wave-swept estuaries, detecting the effects of elevated turbidity can be difficult. The objective of this study was to investigate the effects of shading on ecosystem functions mediated by sandflat primary producers (microphytobenthos) and deep-dwelling surface-feeding macrofauna (Macomona liliana; Bivalvia, Veneroida, Tellinidae). Shade cloths (which reduced incident light intensity by ~80%) were deployed on an exposed, intertidal sandflat to experimentally stress the microphytobenthic community associated with the sediment surface. After 13 weeks, sediment properties, macrofauna and fluxes of oxygen and inorganic nutrients across the sediment-water interface were measured. A multivariate metric of ecosystem function (MF) was generated by combining flux-based response variables, and distance-based linear models were used to determine shifts in the drivers of ecosystem function between non-shaded and shaded plots. No significant differences in MF or in the constituent ecosystem function variables were detected between the shaded and non-shaded plots. However, shading reduced the total explained variation in MF (from 64% in non-shaded plots to 15% in shaded plots) and affected the relative influence of M. liliana and other explanatory variables on MF. This suggests that although shade stress may shift the drivers of ecosystem functioning (consistent with earlier investigations of shading effects on sandflat interaction networks), ecosystem functions appear to have a degree of resilience to those changes. PMID:26214854

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

USDA-ARS?s Scientific Manuscript database

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 ...

Long-term efficacy of in-office and at-home bleaching: a 2-year double-blind randomized clinical trial.

PubMed

Tay, Lidia Yileng; Kose, Carlos; Herrera, Daniel Rodrigo; Reis, Alessandra; Loguercio, Alessandro Dourado

2012-08-01

This parallel, double-blind randomized clinical trial evaluated the 2-year bleaching efficacy and sensitivity produced by at-home (AH) and in-office (IO) bleaching therapies. 60 participants with tooth color darker than C2, without restorations in the anterior dentition and older than 18 years old, were randomly allocated into two groups to receive either IO with 35% hydrogen peroxide or AH with 16% carbamide peroxide. Color was recorded at baseline (BA); 1-week (1W); end of the treatment (ET); and 2 years (2Y) after bleaching, using the Vita Classical shade guide. The perception of TS was recorded on a 0-4 scale during and 2Y after bleaching. The variation in shade guide units (deltaSGU) from BA vs. 1W was compared to deltaSGU from BA vs. 2Y using paired t-test. The percentage of subjects who reported TS was evaluated by Fisher's exact test. The intensity of TS was evaluated by a Mann-Whitney test (alpha=0.05). Both bleaching techniques demonstrated equivalent and significant tooth color shade lightening. No significant color rebound occurred after 2Y for both techniques (P= 0.77 and 0.87, for AH and IO respectively). The absolute risk of TS was similar for IO and AH (P= 0.12), however the intensity of TS was significantly higher for IO (P= 0.001). No subjects reported sensitivity after 2Y.

Re-Assessment of "Water on the Moon" after LCROSS

NASA Technical Reports Server (NTRS)

Gibson, Everett K.; Pillinger, Colin T.

2010-01-01

The LCROSS Mission has produced information about the possible presence of water in a permanently shaded regions of the Moon. Without the opportunity to have a controlled impact into a sun-lite site on the Moon, the LCROSS information must be carefully evaluated. The Apollo samples have provided a large amount of information on the nature of lunar hydrogen, water and other volatiles and this information must be considered in any interpretation of the observed data from the LCROSS and other lunar missions. Perhaps the volatiles seen by the LRO/LCROSS mission might be identical to lunar volatiles within ordinary lunar equatorial materials. Until the control experiment of having an impactor strike an equatorially site is carried out, caution must be taken when interpreting the results from the LCROSS mission.

Influence of shading on ornamental and physiological characteristics during flower development of groundcover rose (Rosa hybrida L.)

NASA Astrophysics Data System (ADS)

Hou, Wei; Luo, Ya; Wang, Xiaorong; Chen, Qing; Sun, Bo; Wang, Yan; Liu, Zejing; Tang, Haoru; Zhang, Yong

2018-04-01

The objective of the present investigation was to study the effect of shading on flower quality during flower development and photosynthetic capacity of groundcover rose (Rosa hybrida L.). The results showed that shade significantly increased flower diameter, levels of soluble protein and soluble sugar, total carotenoids content and superoxide dismutase (SOD) activity, while contents of malondialdehyde (MDA) and total anthocyanins in shaded flowers were significantly decreased as compared to sun-exposed flowers. However, no significant changes were observed in petal color parameters L*, a*, b* and C* between sun exposure and shade treatment plants at each flower developmental stage. Therefore, groundcover rose seemed to have the capacity to shade condition through auto-regulation. These results could provide us with a theoretical basis for further application of groundcover rose in the greening of urban spaces and an understanding of the mechanisms behind the changes induced by shade.

The effect of shade on chlorophyll and anthocyanin content of upland red rice

NASA Astrophysics Data System (ADS)

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

2018-02-01

Upland red rice (Oryza sativa) is a staple food and contains anthocyanin, which can act as antioxidants, plays an important role both for the plant itself and for human health. Levels of antioxidants in rice can be affected by the availability of light. The results showed that the difference of shade, cultivar, and interaction both significantly affect the content of chlorophyll a, chlorophyll b and total chlorophyll. The results also showed that shade could increase chlorophyll in all cultivars tested. The highest levels of chlorophyll a were present in the moderate shade level (n2), then decreased at the shelter level (n3) and increased again at high levels (n4). While on chlorophyll content b, it appears that shade increased chlorophyll b in all cultivars tested and this increase was linear to the increase of shade. The shade treatment may increase the anthocyanin content and the increase depending on the type of cultivar. Increased levels of anthocyanin highest due to shade occurred on Jangkobembe cultivar. The original level of anthocyanin on Jangkobembe cultivar averaged 0.096 mg g-1 increased to 2.487 mg g-1 or increased 26 fold. It is concluded that the shade had a significant effect on the chlorophyll and anthocyanin content.

The effect of shade and vermicompost application on yield and flavonoid levels of Tempuyung (Sonchus arvensis)

NASA Astrophysics Data System (ADS)

Putri, D. P.; Widyastuti, Y.; Dewi, W. S.; Yunus, A.

2018-03-01

This study aims to determine the effect of shade and vermicompost on yield and level of flavonoids in Tempuyung (Sonchus arvensis). The study was conducted in May- August 2016, in Tegal Gede Village, Kab. Karanganyar. Secondary metabolite content analysis was performed in B2P2TOOT laboratory, Tawangmangu. This study used a Completely Randomized Design (CRD) arranged in a split plot. Treatment consists of shade as main plot and the dose of vermicompost as sub plot. Shade treatments are 0% (without shade), 50% and 75%. The dose of vermicompost are 0 g / polybag (control), 250 g / polybag, 500 g / polybag and 750 g / polybag. Each treatment was repeated 3 times and each in experimental unit consist of 2 sample plants. The results showed that the higher levels of shade tend to decrease vegetative growth of plants. Moreover, vermicompost give significant effect on leaf weight, l number, wet and dry weight. The combination of 0% shade and 750 gram vermicompost gave the highest value (P <0.05) to leaf weight ± 186.68 g, wet weight ± 252.08 g and dry weight ± 30,76 gTempuyung. The combination of 50% shade with 0 g vermicompost and 75% shade with 250 g vermicompost show to increasing the content of flavonoid compounds.

Evaluation of bleaching efficacy of 37.5% hydrogen peroxide on human teeth using different modes of activations: An in vitro study

PubMed Central

Bhutani, Neha; Venigalla, Bhuvan Shome; Patil, Jaya Prakash; Singh, Thakur Veerandar; Jyotsna, Sistla Venkata; Jain, Abhilasha

2016-01-01

Introduction: The aim of this in vitro study is to evaluate the role of light and laser sources in the bleaching ability of 37.5% H2 O2 on extracted human teeth. Materials and Methods: About 30 caries-free single-rooted maxillary central incisors were used for the study. Specimens were prepared by sectioning the crown portion of teeth mesiodistally, and labial surface was used for the study. Specimens were then immersed in coffee solution for staining. Color of each tooth was analyzed using Shadestar, a digital shademeter. Specimens were then divided into three groups of 10 each and were subjected to bleaching with 37.5% H2 O2, 37.5% H2 O2 + light activation, and 37.5% H2 O2 + laser activation, respectively. Postbleaching, the color was analyzed for all the specimens immediately and then after 1, 2, and 3 weeks intervals, respectively. Results: All the statistical analyses were done using SPSS version 17. Intra- and inter-group comparisons were done with Friedman test and Kruskal–Wallis ANOVA, respectively. Statistical analysis concluded with a significant improvement in their shade values from baseline in all the three groups. Halogen light activation and laser-activated groups showed comparatively enhanced bleaching results over no-activation group, though the difference was not statistically significant. Conclusion: The results of the present study show that bleaching assisted with halogen light and laser showed increased lightness than nonlight activated group. Durability of bleaching results obtained postbleaching was maintained throughout the experimental trail period of 3 weeks for both halogen light and laser activation group, whereas no-light activation group presented with shade rebound after 2 weeks postbleaching. PMID:27217641

Evaluation of the Diode laser (810nm, 980 nm) on color change of teeth after external bleaching

PubMed Central

Kiomars, Nazanin; Azarpour, Pouneh; Mirzaei, Mansooreh; Hashemi kamangar, Sedighe Sadat; Kharazifard, Mohammad Javad

2016-01-01

Subject and aim: The aim of this study was to evaluate the efficiency of diode laser-activated bleaching systems for color change of teeth. Materials & Methods: 40 premolars with intact enamel surfaces were selected for five external bleaching protocols (n=8). Two different wavelengths of diode laser (810 and 980 nm) with two different hydrogen peroxide concentrations (30% and 46%) were selected for laser bleaching. Group 1 received bleaching (Heydent- Germany) with a 810 nm diode laser; Group 2 received bleaching (Heydent- Germany) with a 980 nm diode laser; Group 3 received bleaching (laser white*20- Biolase) with a 810 nm diode laser; Group 4 received bleaching (laser white*20- Biolase) with a 980 nm diode laser, with an output power of 1.5 W, in continuous wave (cw) mode for each irradiation. Group 5 as control group received 40% hydrogen peroxide (Opalescence Boost, Ultradent-USA) with no light activation. The color of teeth was scored at baseline and 1 week after bleaching with spectrophotometer. Color change data on the CIEL*a*b* system were analyzed statistically by the one-way ANOVA and Tukey's HSD test. Results: All the bleaching techniques resulted in shade change. According to ΔE values, all techniques were effective to bleach the teeth (ΔE ≥ 3). Statistically significant differences were detected among bleaching protocols (p=0.06). Regarding shade change values expressed as ΔL*, Δa*, Δb*, ΔE*, laser bleached groups were no statistically different with each other (p>0.05). Conclusion: Bleaching with different wavelengths of diode laser resulted in the same results. PMID:28765671

Evaluation of the Diode laser (810nm, 980 nm) on color change of teeth after external bleaching.

PubMed

Kiomars, Nazanin; Azarpour, Pouneh; Mirzaei, Mansooreh; Hashemi Kamangar, Sedighe Sadat; Kharazifard, Mohammad Javad; Chiniforush, Nasim

2016-12-30

Subject and aim: The aim of this study was to evaluate the efficiency of diode laser-activated bleaching systems for color change of teeth. Materials & Methods: 40 premolars with intact enamel surfaces were selected for five external bleaching protocols (n=8). Two different wavelengths of diode laser (810 and 980 nm) with two different hydrogen peroxide concentrations (30% and 46%) were selected for laser bleaching. Group 1 received bleaching (Heydent- Germany) with a 810 nm diode laser; Group 2 received bleaching (Heydent- Germany) with a 980 nm diode laser; Group 3 received bleaching (laser white*20- Biolase) with a 810 nm diode laser; Group 4 received bleaching (laser white*20- Biolase) with a 980 nm diode laser, with an output power of 1.5 W, in continuous wave (cw) mode for each irradiation. Group 5 as control group received 40% hydrogen peroxide (Opalescence Boost, Ultradent-USA) with no light activation. The color of teeth was scored at baseline and 1 week after bleaching with spectrophotometer. Color change data on the CIEL*a*b* system were analyzed statistically by the one-way ANOVA and Tukey's HSD test. Results: All the bleaching techniques resulted in shade change. According to ΔE values, all techniques were effective to bleach the teeth (ΔE ≥ 3). Statistically significant differences were detected among bleaching protocols (p=0.06). Regarding shade change values expressed as ΔL*, Δa*, Δb*, ΔE*, laser bleached groups were no statistically different with each other (p>0.05). Conclusion: Bleaching with different wavelengths of diode laser resulted in the same results.

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.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hoffmann, Sabine; Lee, Eleanor

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.more » 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« less

High tolerance to high-light conditions for the protected species Ariocarpus kotschoubeyanus (Cactaceae)

PubMed Central

Arroyo-Pérez, Erika; González-Salvatierra, Claudia; Matías-Palafox, María L.; Jiménez-Sierra, Cecilia

2017-01-01

Abstract We determined the seasonal ecophysiological performance under perennial plants and under high solar radiation for adult individuals from the ‘living rock’ cactus Ariocarpus kotschoubeyanus, which occurs equally under nurse plants and in open spaces. We evaluated the effective quantum yield of photosystem II (ΦPSII) and the dissipation of thermal energy [non-photochemical quenching (NPQ)] thorough the year. The maximum apparent electron transport rate (ETRmax) and the saturating photosynthetically active photon flux density for PSII (PFDsat) were also determined from rapid light curves. We found that although the ΦPSII was higher in shaded sites under potential nurse plants than in exposed sites, all values were close to the optimal value of 0.83. The high ΦPSII found for A. kotschoubeyanus plants suggests that they use a great proportion of the absorbed light for photosynthesis, under nurse plants as well as in open spaces. We also found higher NPQ values in exposed sites than in shaded ones but only in Autumn, thus reducing the risk of photoinhibition. In addition, the PFDsat was higher in exposed sites than in shaded ones in Spring, Summer and Autumn, but in Winter there were no differences between treatments. We also found high saturating light levels for ETR (PFDsat higher than 1378 μmol m−2 s−1) in all seasons but in winter for shaded and non-shaded plants. Our findings indicate that A. kotschoubeyanus plants use a great proportion of the light that they absorb for photosynthesis. This high tolerance to high-light conditions could explain why A. kotschoubeyanus do not show preferences for protected sites under nurse plants. PMID:28729902

Effect of coping thickness and background type on the masking ability of a zirconia ceramic.

PubMed

Tabatabaian, Farhad; Taghizade, Fateme; Namdari, Mahshid

2018-01-01

The masking ability of zirconia ceramics as copings is unclear. The purpose of this in vitro study was to evaluate the effect of coping thickness and background type on the masking ability of a zirconia ceramic and to determine zirconia coping thickness cut offs for masking the backgrounds investigated. Thirty zirconia disks in 3 thickness groups of 0.4, 0.6, and 0.8 mm were placed on 9 backgrounds to measure CIELab color attributes using a spectrophotometer. The backgrounds included A1, A2, and A3.5 shade composite resin, A3 shade zirconia, nickel-chromium alloy, nonprecious gold-colored alloy, amalgam, black, and white. ΔE values were measured to determine color differences between the specimens on the A2 shade composite resin background and the same specimens on the other backgrounds. The color change (ΔE) values were compared with threshold values for acceptability (ΔE=5.5) and perceptibility (ΔE=2.6). Repeated measures ANOVA, the Bonferroni test, and 1-sample t tests were used to analyze data (α=.05). Mean ΔE values ranged between 1.44 and 7.88. The zirconia coping thickness, the background type, and their interaction affected the CIELab and ΔE values (P<.001). To achieve ideal masking, the minimum thickness of a zirconia coping should be 0.4 mm for A1 and A3.5 shade composite resin, A3 shade zirconia, and nonprecious gold-colored alloy, 0.6 mm for amalgam, and 0.8 mm for nickel-chromium alloy. Copyright © 2017 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Season-dependent and independent responses of Mediterranean scrub to light conditions.

PubMed

Zunzunegui, María; Díaz-Barradas, Mari Cruz; Jáuregui, Juan; Rodríguez, Herminia; Álvarez-Cansino, Leonor

2016-05-01

Semi-arid plant species cope with excess of solar radiation with morphological and physiological adaptations that assure their survival when other abiotic stressors interact. At the leaf level, sun and shade plants may differ in the set of traits that regulate environmental stressors. Here, we evaluated if leaf-level physiological seasonal response of Mediterranean scrub species (Myrtus communis, Halimium halimifolium, Rosmarinus officinalis, and Cistus salvifolius) depended on light availability conditions. We aimed to determine which of these responses prevailed independently of the marked seasonality of Mediterranean climate, to define a leaf-level strategy in the scrub community. Thirty six leaf response variables - involving gas exchange, water status, photosystem II photochemical efficiency, photosynthetic pigments and leaf structure - were seasonally measured in sun exposed and shaded plants under field conditions. Physiological responses showed a common pattern throughout the year, in spite of the marked seasonality of the Mediterranean climate and of species-specific differences in the response to light intensity. Variables related to light use, CO2 assimilation, leaf pigment content, and LMA (leaf mass area) presented differences that were consistent throughout the year, although autumn was the season with greater contrast between sun and shade plants. Our data suggest that in Mediterranean scrub shade plants the lutein pool could have an important role in the photoprotection of the photosynthetic tissues. There was a negative linear correlation between the ratio lutein/total chlorophylls and the majority of leaf level variables. The combined effect of abiotic stress factors (light and drought or light and cold) was variable-specific, in some cases enhancing differences between sun and shade plants, while in others leading to unified strategies in all scrub species. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Changes to Glazed Dental Ceramic Shade, Roughness, and Microhardness after Bleaching and Simulated Brushing.

PubMed

Rodrigues, Carlos Roberto Teixeira; Turssi, Cecilia Pedroso; Amaral, Flávia Lucisano Botelho; Basting, Roberta Tarkany; França, Fabiana Mantovani Gomes

2017-09-05

To evaluate shade stability, surface roughness, microhardness, and compressive strength of a glazed feldspathic ceramic subjected to bleaching and simulated brushing. Eighty-eight glazed feldspathic ceramic specimens were made from microparticulate leucite and divided into eight groups (n = 10). The whitening products used were: Opalescence Trèswhite Supreme (Ultradent), Opalescence®\\ PF 15% (Ultradent), and Oral-B 3D White Whitestrips. All substances for whitening were used for 4 hours/day for a period of 14 days; the control group was not bleached. Next, half of the specimens were individually brushed. Microhardness and surface roughness data were subjected to three-way ANOVA and Tukey test. The diametrical tensile strength data were subjected to two-way ANOVA. The shade change data were analyzed using Kruskal-Wallis, Mann-Whitney, and the Student-Newman-Keuls test. The significance level was set at 5%. Glazed feldspathic ceramic surface microhardness was significantly affected by bleaching agents (p = 0.007). Initially, glazed ceramic microhardness was significantly higher than that observed after contact with the bleaching agents, whether or not brushing was performed. The specimens submitted to bleaching in preloaded trays presented lower surface roughness values after brushing (p = 0.037). The surface roughness was significantly lower in the brushed specimens (p = 0.044). The diametrical tensile strength was not significantly affected by the application of bleaching agents (p = 0.563) or by brushing (p = 0.477). When the specimens were brushed, however, shade change was significantly influenced by the bleaching agent used (p = 0.041). Bleaching agents associated with brushing cycles can alter surface properties and shade stability of glazed feldspathic ceramics, though such findings may not reflect the performance of unglazed feldspathic ceramics. © 2017 by the American College of Prosthodontists.

Influence of season and microclimate on fertility of dairy cows in a hot-arid environment.

PubMed

Ray, D E; Jassim, A H; Armstrong, D V; Wiersma, F; Schuh, J D

1992-08-01

Records were obtained over a 3 year period from six Holstein dairy farms of 300 to 500 cows each in the Phoenix, Ariz. area. Dairies were selected on the basis of similar management practices, herd size, milk production and facilities (with the exception of cooling systems). Microclimatic modifications (two dairies each) were shade only (approximately 3.7 m2/cow), evaporative-cooled shades and low-pressure water foggers under the shades. Data were categorized by season of calving (spring, Feb.-May; summer, June-Sept.; and fall, Oct.-Jan.). Traits evaluated were calving interval, days open and services/conception. Calving interval was shortest for cows calving in the spring (378 days), intermediate in fall (382 days) and longest in summer (396 days). Similar seasonal trends were observed for days open (103, 103 and 119 days, respectively) and services/conception (1.54, 1.81 and 1.93, respectively). All differences between spring and summer were significant (P less than 0.05). Calving interval and days open were less for evaporative-cooled groups (374 and 98 days, respectively), with no difference between shade only and foggers (391 and 392 days, 112 and 116 days, respectively). Services/conception were similar for all groups (1.72 to 1.79). A significant interaction between microclimate and season for services/conception could be interpreted as (i) smaller season differences for evaporative-cooled groups than for shade or foggers, or (ii) a change in the ranking of control and fogger groups during summer versus fall. Evaporative cooling was more effective than fogging for reducing the detrimental effects of seasonal high temperatures on fertility.

Lightness, chroma, and hue distributions of a shade guide as measured by a spectroradiometer.

PubMed

Lee, Yong-Keun; Yu, Bin; Lim, Ho-Nam

2010-09-01

The color attributes of commercially available shade guides have been measured by spectrophotometers (SP), which are designed to measure flat surfaces. However, there is limited information on the color distribution of shade guides as measured by spectroradiometers (SR), which are capable of measuring the color of curved surfaces. The purpose of this study was to determine the distributions of lightness (CIE L*) and chroma (C*(ab)) step intervals between adjacent shade tabs of a shade guide based on the lightness, chroma, and hue attributes measured by an SR. Lightness, chroma, hue angle, and CIE a* and b* values of the shade tabs (n=26) from a shade guide (Vitapan 3D-Master) were measured by an SR under daylight conditions. The distributions of the ratios in lightness and chroma of each tab compared with the lowest lightness tab or the lowest chroma tab were determined. The values for each color parameter were analyzed by a 3-way ANOVA with the factors of lightness, chroma, and hue designations of the shade tabs (alpha=.05). The chroma and CIE a* and b* values were influenced by the lightness, chroma, and hue designations of the shade tabs (P<.001); however, the lightness and hue angle were influenced by the lightness and hue designations, but not by the chroma designation. Distributions for the CIE a* and b* values, in each lightness group, corresponded with the chroma designation. However, the intervals in the lightness and chroma scales between adjacent tabs were not uniform. The intervals in the color parameters between adjacent shade tabs were not uniform based on SR measurements. Therefore, a shade guide in which shade tabs are more equally spaced by the color attributes, based on the values as measured by an SR along with observers' responses with respect to the equality of the intervals, should be devised. Copyright © 2010 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Color distribution of a shade guide in the value, chroma, and hue scale.

PubMed

Ahn, Jin-Soo; Lee, Yong-Keun

2008-07-01

Shade tabs in a shade guide are matched to teeth in the order of value, hue, and chroma; therefore, information on the distribution of shade tabs is essential for clinical application of a shade guide. However, there is limited information on the color distribution as sorted by these 3 parameters of a recently introduced shade guide. The purposes of this study were to determine the color distributions of tabs from a shade guide in the value (CIE L*), chroma (C*(ab)), and hue scale, and to determine the distribution of step intervals between adjacent tabs by value and chroma. The color of shade tabs (n=29) from a shade guide (Vitapan 3D-Master) was measured to determine the distribution of shade tabs by the value, chroma, hue angle, and CIE a* and b* values. The distribution of the ratios of the value and the chroma of each tab, when compared with the lowest value tab or the lowest chroma tab, was also determined. The data for each color parameter were analyzed by a 3-way ANOVA with the factors of value, chroma, and hue designations of the tabs (alpha=.05). The value, chroma, hue angle, and CIE a* and b* values were influenced by the value, chroma, and hue designations of shade tabs (P<.001). The distributions of the chroma of the tabs within the same value group were relatively ordered, but the values of different value groups overlapped in several instances. Distributions for the CIE a* and b* values reflected the chroma designations in each value group. In the same value group, L, M, and R hue designations corresponded with the manufacturer's stated hue, such as a yellow hue for the L designation and a red hue for the R designation. The distance in the value and chroma scales between adjacent tabs was not uniform. The color distribution of the Vitapan 3D-Master shade guide was more ordered than previously reported color distributions of other, traditional shade guides. However, the interval in the color parameters between adjacent tabs was not uniform; therefore, shade tabs spaced equally, according to the color parameters, should be studied based on the observer's response data.

Sprinklers and shade cool cows and reduce insect-avoidance behavior in pasture-based dairy systems.

PubMed

Kendall, P E; Verkerk, G A; Webster, J R; Tucker, C B

2007-08-01

The body temperature of dairy cows in pastoral systems during summer reaches a peak during and following the p.m. milking. Shade and sprinklers can be used separately or in combination at the milking parlor to reduce heat load. Farmers anecdotally report that the use of sprinklers reduces irritation from insects that occurs while cows are waiting for milking. Once daily, we assessed the effectiveness of short-term exposure to shade and sprinklers for cooling cows [via respiration rate and body (vaginal) temperature] and reducing insect-avoidance behaviors before the p.m. milking in a pasture-based dairy system. Head position was measured as an indicator of whether cattle were avoiding water from the sprinklers. Forty-eight Holstein-Friesian dairy cows were divided into 12 groups (4 cows per group, n = 3 groups/treatment) and were exposed to 1 of 4 treatments for 90 min before the p.m. milking: 1) shade, 2) sprinklers, 3) shade and sprinklers, or 4) uncooled control. Respiration rate was reduced by 30% with shade alone compared with controls [54 vs. 78 +/- 2.3 ( +/- SED) breaths/min, respectively]. Sprinklers alone (30 +/- 2.3 breaths/min) and the combined effects of shade and sprinklers (24 +/- 2.3 breaths/min) reduced the respiration rate by 60 and 67%, respectively, compared with controls. Shaded cows had lower body temperatures during the 90-min treatment period compared with controls (shade: 38.6 degrees C; shade and sprinklers: 38.6 degrees C; control: 38.9 +/- 0.09 degrees C). The decrease in body temperature of cows under sprinklers was more marked than for shade alone and remained lower for at least 4 h after milking (sprinklers: 38.7 degrees C; shade and sprinklers: 38.6 degrees C; shade: 38.9 degrees C; control: 39.2 +/- 0.10 degrees C). The sprinkler treatment reduced the number of tail flicks (control: 12.6 vs. sprinklers: 6.6 +/- 2.4 flicks/min) and hoof stamps (control: 4.4 vs. sprinkler: 2.2 +/- 0.5 stamps/min). Cows exposed to sprinklers spent more time with their heads lowered compared with cows in the shaded and control treatments. The reductions in body temperature and respiration rate attributable to shade and sprinklers were greatest when the temperature-humidity index and heat-load index were > or = 69 and 77, respectively, and cows benefited from cooling when these levels were exceeded.

Silviculture's role in managing boreal forests

Treesearch

Russell T. Graham; Theresa B. Jain

1998-01-01

Boreal forests, which are often undeveloped, are a major source of raw materials for many countries. They are circumpolar in extent and occupy a belt to a width of 1000 km in certain regions. Various conifer and hardwood species ranging from true firs to poplars grow in boreal forests. These species exhibit a wide range of shade tolerance and growth characteristics,...

A statistical light use efficiency model explains 85% variations in global GPP

NASA Astrophysics Data System (ADS)

Jiang, C.; Ryu, Y.

2016-12-01

Photosynthesis is a complicated process whose modeling requires different levels of assumptions, simplification, and parameterization. Among models, light use efficiency (LUE) model is highly compact but powerful in monitoring gross primary production (GPP) from satellite data. Most of LUE models adopt a multiplicative from of maximum LUE, absorbed photosynthetically active radiation (APAR), and temperature and water stress functions. However, maximum LUE is a fitting parameter with large spatial variations, but most studies only use several biome dependent constants. In addition, stress functions are empirical and arbitrary in literatures. Moreover, meteorological data used are usually coarse-resolution, e.g., 1°, which could cause large errors. Finally, sunlit and shade canopy have completely different light responses but little considered. Targeting these issues, we derived a new statistical LUE model from a process-based and satellite-driven model, the Breathing Earth System Simulator (BESS). We have already derived a set of global radiation (5-km resolution), carbon and water fluxes (1-km resolution) products from 2000 to 2015 from BESS. By exploring these datasets, we found strong correlation between APAR and GPP for sunlit (R2=0.84) and shade (R2=0.96) canopy, respectively. A simple model, only driven by sunlit and shade APAR, was thus built based on linear relationships. The slopes of the linear function act as effective LUE of global ecosystem, with values of 0.0232 and 0.0128 umol C/umol quanta for sunlit and shade canopy, respectively. When compared with MPI-BGC GPP products, a global proxy of FLUXNET data, BESS-LUE achieved an overall accuracy of R2 = 0.85, whereas original BESS was R2 = 0.83 and MODIS GPP product was R2 = 0.76. We investigated spatiotemporal variations of the effective LUE. Spatially, the ratio of sunlit to shade values ranged from 0.1 (wet tropic) to 4.5 (dry inland). By using maps of sunlit and shade effective LUE the accuracy of BESS-LUE further reached R2 = 0.88. Temporally, both sunlit and shade effective LUE had seasonal peak values in NH summer, and both showed significant increasing trends. Overall, BESS-LUE exhibited promising potential in global GPP mapping. We are going to evaluate it using FLUXNET2015 database and satellite solar Induced Fluorescence (SIF) data.

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 mean values of the Chl fluorescence decrease ratio R Fd of blue-shade and half-shade leaves fit well into the strong linear correlation with the net photosynthetic rates P N of sun and shade leaves, thus unequivocally indicating that the determination of the Chl fluorescence decrease ratio R Fd is a fast and indirect measurement of the photosynthetic activity of leaves. The investigations clearly demonstrate that the photosynthetic capacity and pigment composition of leaves and chloroplasts strongly depend on the amounts and quality of light received by the leaves.

Color difference thresholds in dentistry.

PubMed

Paravina, Rade D; Ghinea, Razvan; Herrera, Luis J; Bona, Alvaro D; Igiel, Christopher; Linninger, Mercedes; Sakai, Maiko; Takahashi, Hidekazu; Tashkandi, Esam; Perez, Maria del Mar

2015-01-01

The aim of this prospective multicenter study was to determine 50:50% perceptibility threshold (PT) and 50:50% acceptability threshold (AT) of dental ceramic under simulated clinical settings. The spectral radiance of 63 monochromatic ceramic specimens was determined using a non-contact spectroradiometer. A total of 60 specimen pairs, divided into 3 sets of 20 specimen pairs (medium to light shades, medium to dark shades, and dark shades), were selected for psychophysical experiment. The coordinating center and seven research sites obtained the Institutional Review Board (IRB) approvals prior the beginning of the experiment. Each research site had 25 observers, divided into five groups of five observers: dentists-D, dental students-S, dental auxiliaries-A, dental technicians-T, and lay persons-L. There were 35 observers per group (five observers per group at each site ×7 sites), for a total of 175 observers. Visual color comparisons were performed using a viewing booth. Takagi-Sugeno-Kang (TSK) fuzzy approximation was used for fitting the data points. The 50:50% PT and 50:50% AT were determined in CIELAB and CIEDE2000. The t-test was used to evaluate the statistical significance in thresholds differences. The CIELAB 50:50% PT was ΔEab  = 1.2, whereas 50:50% AT was ΔEab  = 2.7. Corresponding CIEDE2000 (ΔE00 ) values were 0.8 and 1.8, respectively. 50:50% PT by the observer group revealed differences among groups D, A, T, and L as compared with 50:50% PT for all observers. The 50:50% AT for all observers was statistically different than 50:50% AT in groups T and L. A 50:50% perceptibility and ATs were significantly different. The same is true for differences between two color difference formulas ΔE00 /ΔEab . Observer groups and sites showed high level of statistical difference in all thresholds. Visual color difference thresholds can serve as a quality control tool to guide the selection of esthetic dental materials, evaluate clinical performance, and interpret visual and instrumental findings in clinical dentistry, dental research, and subsequent standardization. The importance of quality control in dentistry is reinforced by increased esthetic demands of patients and dental professionals. © 2015 Wiley Periodicals, Inc.

The least-squares mixing models to generate fraction images derived from remote sensing multispectral data

NASA Technical Reports Server (NTRS)

Shimabukuro, Yosio Edemir; Smith, James A.

1991-01-01

Constrained-least-squares and weighted-least-squares mixing models for generating fraction images derived from remote sensing multispectral data are presented. An experiment considering three components within the pixels-eucalyptus, soil (understory), and shade-was performed. The generated fraction images for shade (shade image) derived from these two methods were compared by considering the performance and computer time. The derived shade images are related to the observed variation in forest structure, i.e., the fraction of inferred shade in the pixel is related to different eucalyptus ages.

Factors affecting establishment success of the endangered Caribbean cactus Harrisia portoricensis (Cactaceae).

PubMed

Rojas-Sandoval, Julissa; Meléndez-Ackerman, Elvia

2012-06-01

Early plant stages may be the most vulnerable within the life cycle of plants especially in arid ecosystems. Interference from exotic species may exacerbate this condition. We evaluated germination, seedling survival and growth in the endangered Caribbean cactus Harrisia portoricensis, as a function of sunlight exposure (i.e., growing under open and shaded areas), different shade providers (i.e., growing under two native shrubs and one exotic grass species), two levels of predation (i.e., exclusion and non-exclusion) and variable microenvironmental conditions (i.e., temperature, PAR, humidity). Field experiments demonstrated that suitable conditions for germination and establishment of H. portoricensis seedling are optimal in shaded areas beneath the canopy of established species, but experiments also demonstrated that the identity of the shade provider can have a significant influence on the outcome of these processes. Harrisia portoricensis seedlings had higher probabilities of survival and grew better (i.e., larger diameters) when they were transplanted beneath the canopy of native shrubs, than beneath the exotic grass species, where temperature and solar radiation values were on average much higher than those obtained under the canopies of native shrubs. We also detected that exclusion from potential predators did not increase seedling survival. Our combined results for H. portoricensis suggested that the modification of microenvironmental conditions by the exotic grass may lower the probability of recruitment and establishment of this endangered cactus species.

Herbivores modify selection on plant functional traits in a temperate rainforest understory.

PubMed

Salgado-Luarte, Cristian; Gianoli, Ernesto

2012-08-01

There is limited evidence regarding the adaptive value of plant functional traits in contrasting light environments. It has been suggested that changes in these traits in response to light availability can increase herbivore susceptibility. We tested the adaptive value of plant functional traits linked with carbon gain in contrasting light environments and also evaluated whether herbivores can modify selection on these traits in each light environment. In a temperate rainforest, we examined phenotypic selection on functional traits in seedlings of the pioneer tree Aristotelia chilensis growing in sun (canopy gap) and shade (forest understory) and subjected to either natural herbivory or herbivore exclusion. We found differential selection on functional traits depending on light environment. In sun, there was positive directional selection on photosynthetic rate and relative growth rate (RGR), indicating that selection favors competitive ability in a high-resource environment. Seedlings with high specific leaf area (SLA) and intermediate RGR were selected in shade, suggesting that light capture and conservative resource use are favored in the understory. Herbivores reduced the strength of positive directional selection acting on SLA in shade. We provide the first demonstration that natural herbivory rates can change the strength of selection on plant ecophysiological traits, that is, attributes whose main function is resource uptake. Research addressing the evolution of shade tolerance should incorporate the selective role of herbivores.

Evaluating the Influence of Postsession Reinforcement on Choice of Reinforcers

ERIC Educational Resources Information Center

Kodak, Tiffany; Lerman, Dorothea C.; Call, Nathan

2007-01-01

Factors that influence reinforcer choice have been examined in a number of applied studies (e.g., Neef, Mace, Shea, & Shade, 1992; Shore, Iwata, DeLeon, Kahng, & Smith, 1997; Tustin, 1994). However, no applied studies have evaluated the effects of postsession reinforcement on choice between concurrently available reinforcers, even though basic…

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.

Characterizing visual asymmetries in contrast perception using shaded stimuli.

PubMed

Chacón, José; Castellanos, Miguel Ángel; Serrano-Pedraza, Ignacio

2015-01-01

Previous research has shown a visual asymmetry in shaded stimuli where the perceived contrast depended on the polarity of their dark and light areas (Chacón, 2004). In particular, circles filled out with a top-dark luminance ramp were perceived with higher contrast than top-light ones although both types of stimuli had the same physical contrast. Here, using shaded stimuli, we conducted four experiments in order to find out if the perceived contrast depends on: (a) the contrast level, (b) the type of shading (continuous vs. discrete) and its degree of perceived three-dimensionality, (c) the orientation of the shading, and (d) the sign of the perceived contrast alterations. In all experiments the observers' tasks were to equate the perceived contrast of two sets of elements (usually shaded with opposite luminance polarity), in order to determine the subjective equality point. Results showed that (a) there is a strong difference in perceived contrast between circles filled out with luminance ramp top-dark and top-light that is similar for different contrast levels; (b) we also found asymmetries in contrast perception with different shaded stimuli, and this asymmetry was not related with the perceived three-dimensionality but with the type of shading, being greater for continuous-shading stimuli; (c) differences in perceived contrast varied with stimulus orientation, showing the maximum difference on vertical axis with a left bias consistent with the bias found in previous studies that used visual-search tasks; and (d) asymmetries are consistent with an attenuation in perceived contrast that is selective for top-light vertically-shaded stimuli.

[A preliminary study on the color effect of IPS Empress all-ceramic veneers].

PubMed

Li, Zhi-yong; Cheng, Xiang-rong; Wang, Yi-ning

2004-09-01

To evaluate the opaquing capacity, color compatibility and stability of IPS Empress all-ceramic veneers. A total of 86 IPS Empress all-ceramic veneers were made for 18 patients. The patients were divided into three groups: Group A was tetracycline teeth, 64 veneers for 5 patients; Group B was non-tetracycline teeth, 22 veneers for 13 patients; Group C was 22 natural vital teeth with normal color as control group. Before and after veneers were inserted, ShadeEye NCC was employed to obtain L * a * b * values of each tooth. The values of cemented veneers used as the baseline, the L * a * b * values of each veneer were measured half a year, 1 year, and 2 years after restoration respectively. All L * a * b * values at different evaluation times were analyzed by SPSS 10.0. Before and after veneers were restored, the L * a * b * values of both Group A and Group B were significantly different, the color difference being 5.01 and 4.15 respectively. The color difference between Group A and selected shade guides was 2.45. Compared with the baseline value, the L * value of Group A significantly decreased 2 years after restoration, but the DeltaE of different evaluation times was not significantly different. The color difference between Group B and Group C was 0.22 and there was no significant color difference after restoration. IPS Empress all-ceramic veneers have excellent opaquing capacity, color compatibility and stability to non-tetracycline teeth. To tetracycline teeth IPS Empress all-ceramic veneers have a certain opaquing capacity, but they cannot completely match with shade guides; the L * value is significantly different after restoration and further studies are needed to evaluate its color effect.

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.

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

[Effects of soil moisture content and light intensity on the plant growth and leaf physiological characteristics of squash].

PubMed

Du, She-ni; Bai, Gang-shuan; Liang, Yin-li

2011-04-01

A pot experiment with artificial shading was conducted to study the effects of soil moisture content and light intensity on the plant growth and leaf physiological characteristics of squash variety "Jingyingyihao". Under all test soil moisture conditions, 30% shading promoted the growth of "Jingyingyihao", with the highest yield at 70% - 80% soil relative moisture contents. 70% shading inhibited plant growth severely, only flowering and not bearing fruits, no economic yield produced. In all treatments, there was a similar water consumption trend, i. e., both the daily and the total water consumption decreased with increasing shading and decreasing soil moisture content. Among all treatments, 30% shading and 70% - 80% soil relative moisture contents had the highest water use efficiency (2.36 kg mm(-1) hm(-2)) and water output rate (1.57 kg mm(-1) hm(-2)). The net photosynthetic rate, transpiration rate, stomatal conductance, and chlorophyll content of squash leaves decreased with increasing shading, whereas the intercellular CO2 concentration was in adverse. The leaf protective enzyme activity and proline content decreased with increasing shading, and the leaf MAD content decreased in the order of 70% shading, natural radiation, and 30% shading. Under the three light intensities, the change characteristics of squash leaf photosynthesis, protective enzyme activity, and proline and MAD contents differed with the increase of soil relative moisture content.

Spectral CT metal artifact reduction with an optimization-based reconstruction algorithm

NASA Astrophysics Data System (ADS)

Gilat Schmidt, Taly; Barber, Rina F.; Sidky, Emil Y.

2017-03-01

Metal objects cause artifacts in computed tomography (CT) images. This work investigated the feasibility of a spectral CT method to reduce metal artifacts. Spectral CT acquisition combined with optimization-based reconstruction is proposed to reduce artifacts by modeling the physical effects that cause metal artifacts and by providing the flexibility to selectively remove corrupted spectral measurements in the spectral-sinogram space. The proposed Constrained `One-Step' Spectral CT Image Reconstruction (cOSSCIR) algorithm directly estimates the basis material maps while enforcing convex constraints. The incorporation of constraints on the reconstructed basis material maps is expected to mitigate undersampling effects that occur when corrupted data is excluded from reconstruction. The feasibility of the cOSSCIR algorithm to reduce metal artifacts was investigated through simulations of a pelvis phantom. The cOSSCIR algorithm was investigated with and without the use of a third basis material representing metal. The effects of excluding data corrupted by metal were also investigated. The results demonstrated that the proposed cOSSCIR algorithm reduced metal artifacts and improved CT number accuracy. For example, CT number error in a bright shading artifact region was reduced from 403 HU in the reference filtered backprojection reconstruction to 33 HU using the proposed algorithm in simulation. In the dark shading regions, the error was reduced from 1141 HU to 25 HU. Of the investigated approaches, decomposing the data into three basis material maps and excluding the corrupted data demonstrated the greatest reduction in metal artifacts.

Stream shading, summer streamflow and maximum water temperature following intense wildfire in headwater streams

Treesearch

Michael Amaranthus; Howard Jubas; David Arthur

1989-01-01

Adjacent headwater streams were monitored for postfire shade, summer streamflow and maximum water temperature following the 40,000 ha Silver Complex fire in southern Oregon. Average postfire shade (30 percent) for the three streams was considerably less than prefire shade (est.>90 percent). Dramatic increases in direct solar radiation resulted in large but variable...

Effects of street tree shade on asphalt concrete pavement performance

Treesearch

E.G. McPherson; J. Muchnick

2005-01-01

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

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

PubMed

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.

Response of Artemisia annua L. to shade and manure fertilizer application in lowland altitude

NASA Astrophysics Data System (ADS)

Permana, H. H.; Widyastuti, Y.; Samanhudi; Yunus, A.

2018-03-01

Artemisia is a plant producing artemisinin substance which is the main compound in the treatment of malaria. Artemisia comes from China, usually grows wild in native habitats in the plains with an altitude of 1,000-1,500 meters above the sea level. Artemisia development efforts in Indonesia hampered by limited land with the required altitude due to their competition with vegetable crops. Based on this reason, this research is conducted to observe the growth of artemisia planted in lowland with the help of shade and manure. This study aims to determine the level of shade and best manure on the growth of Artemisia. Research conducted at the Laboratory of the Faculty of Agriculture UNS Jumantono using nested design with two factors, shade as main factor and manure fertilizer as sub factor. The data analysis used F test with confidence level of 5%, if significant, then continued with DMRT (Duncan Multiple Range Test). The results showed the treatment of shade gave no difference in growth within 50% shade, 75% shade as well as without shade treatment. Goat manure fertilizer gave the highest result and able to increase plant height, number of branches, flower weight and root volume.

The effects of providing portable shade at pasture on dairy cow behavior and physiology.

PubMed

Palacio, S; Bergeron, R; Lachance, S; Vasseur, E

2015-09-01

Access to pasture has advantages for cows such as reduced lameness and improved udder health, but also may expose cows to stressors such as extreme heat. The objective of this study was to understand how portable shade affected physiological and behavioral responses of pastured dairy cows in a Canadian summer. Over 8wk, a total of 24 lactating Holstein cows were separated into 2 treatments, one with access to shade and a control without access to shade. The cows were pastured in groups of 4, with 3 field sections per treatment. Instantaneous scan sampling of behaviors (drinking, lying, grazing, other) performed in the shade or not were recorded every 5min for 3h/d during the hottest part of the day (peak hours: 1130-1530h) 3d/wk. Ambient temperature, humidity, and vaginal temperature were recorded at 10-min intervals. Daily milk production was also recorded. Differences between treatments by week were analyzed using the generalized linear mixed model with group as random effect and treatment as fixed effect. Cows with shade access were observed at the water trough up to 6.42 times less and lying down up to 1.75 times more. Cows with shade access grazed up to 1.5 times more but only when the temperature-humidity index was above their comfort threshold (≥72) during the hottest part of the day (wk 2). Cows sought shade when it was made available, but spent less than half of their time observed (%) in the shade (40.8±4.67) with the exception of wk 2 when most of the time was spent under the shade (74.3±4.77). Daily lying time was highest during peak hours for cows with shade access. However, no overall difference in total lying time between the 2 treatments was observed. No differences were found in vaginal temperature or milk production between treatments with the exception of wk 1 for daily milk production, which was higher for cows in the control treatment. In conclusion, cows sought shade when it was provided at pasture, whereas cows without access to shade seemed to alter their behavior to cope with heat stress, as seen from the lack of physiological differences between treatments. The results indicate that providing cows with access to pasture under a temperate climate does not seem to have any detrimental physiological or production effects and providing them with shade can potentially decrease production costs and help with water conservation strategies as fewer cows were observed at the water when shade was provided. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Spectrophotometric evaluation of optical performances of polarizing technologies for smart window applications

NASA Astrophysics Data System (ADS)

Levati, N.; Vitali, L.; Fustinoni, D.; Niro, A.

2014-11-01

In recent years, window-integrated solar protection systems are used and studied as a promising energy saving technology, both for cold and hot climates. In particular, smart windows, whose optical proprieties in the solar wavelength range can somehow be controlled, show interesting results, especially in reducing the air conditioning power consumption. With the improvement of nanolithography techniques as well as with the possibility of designing polarization intervals, coupled polarizing films show a good potential as a dynamic and wavelength-selective shading technology. In this paper, UV-Vis-NIR spectrophotometric measurements are carried out on two polarizing technologies, Polaroid crystalline polarizer and Wire Grid broadband polarizer, in single- and double- film layout, to evaluate their optical performances, i.e. spectral transmittance, reflectance and absorptivity. The solar radiation glazing factors, according to the standard UNI EN 410, are calculated. The measured data are also analyzed in detail to emphasize the optical peculiarities of the materials under study that do not stand out from the standard parameters, as well as the specific problems that arise in spectrophotometric evaluations of polarizing films.

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 with a better C-balance at low irradiance. Under those conditions tolerance to other stresses is probably more important for the performance of shade-tolerant species. PMID:24550922

Impacts of light shading and nutrient enrichment geo-engineering approaches on the productivity of a stratified, oligotrophic ocean ecosystem.

PubMed

Hardman-Mountford, Nick J; Polimene, Luca; Hirata, Takafumi; Brewin, Robert J W; Aiken, Jim

2013-12-06

Geo-engineering proposals to mitigate global warming have focused either on methods of carbon dioxide removal, particularly nutrient fertilization of plant growth, or on cooling the Earth's surface by reducing incoming solar radiation (shading). Marine phytoplankton contribute half the Earth's biological carbon fixation and carbon export in the ocean is modulated by the actions of microbes and grazing communities in recycling nutrients. Both nutrients and light are essential for photosynthesis, so understanding the relative influence of both these geo-engineering approaches on ocean ecosystem production and processes is critical to the evaluation of their effectiveness. In this paper, we investigate the relationship between light and nutrient availability on productivity in a stratified, oligotrophic subtropical ocean ecosystem using a one-dimensional water column model coupled to a multi-plankton ecosystem model, with the goal of elucidating potential impacts of these geo-engineering approaches on ecosystem production. We find that solar shading approaches can redistribute productivity in the water column but do not change total production. Macronutrient enrichment is able to enhance the export of carbon, although heterotrophic recycling reduces the efficiency of carbon export substantially over time. Our results highlight the requirement for a fuller consideration of marine ecosystem interactions and feedbacks, beyond simply the stimulation of surface blooms, in the evaluation of putative geo-engineering approaches.

Impacts of light shading and nutrient enrichment geo-engineering approaches on the productivity of a stratified, oligotrophic ocean ecosystem

PubMed Central

Hardman-Mountford, Nick J.; Polimene, Luca; Hirata, Takafumi; Brewin, Robert J. W.; Aiken, Jim

2013-01-01

Geo-engineering proposals to mitigate global warming have focused either on methods of carbon dioxide removal, particularly nutrient fertilization of plant growth, or on cooling the Earth's surface by reducing incoming solar radiation (shading). Marine phytoplankton contribute half the Earth's biological carbon fixation and carbon export in the ocean is modulated by the actions of microbes and grazing communities in recycling nutrients. Both nutrients and light are essential for photosynthesis, so understanding the relative influence of both these geo-engineering approaches on ocean ecosystem production and processes is critical to the evaluation of their effectiveness. In this paper, we investigate the relationship between light and nutrient availability on productivity in a stratified, oligotrophic subtropical ocean ecosystem using a one-dimensional water column model coupled to a multi-plankton ecosystem model, with the goal of elucidating potential impacts of these geo-engineering approaches on ecosystem production. We find that solar shading approaches can redistribute productivity in the water column but do not change total production. Macronutrient enrichment is able to enhance the export of carbon, although heterotrophic recycling reduces the efficiency of carbon export substantially over time. Our results highlight the requirement for a fuller consideration of marine ecosystem interactions and feedbacks, beyond simply the stimulation of surface blooms, in the evaluation of putative geo-engineering approaches. PMID:24132201

75 FR 52724 - Procurement List Additions

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-27

...: 8405-00-FAB-0201--Man's, S/S, Air Force Shade 1550, Size 13\\1/ 2\\ NSN: 8405-00-FAB-0202--Man's, S/S, Air Force Shade 1550, Size 14 NSN: 8405-00-FAB-0203--Man's, S/S, Air Force Shade 1550, Size 14 \\1/ 2\\ NSN: 8405-00-FAB-0204--Man's, S/S, Air Force Shade 1550, Size 15 NSN: 8405-00-FAB-0212--Man's, S/S...

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

Treesearch

Jean Lienard; Ionut Florescu; Nikolay Strigul

2015-01-01

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...

Evaluating the Community Land Model in a pine stand with shading manipulations and 13CO 2 labeling

DOE PAGES

Mao, Jiafu; Ricciuto, Daniel M.; Thornton, Peter E.; ...

2016-02-03

Carbon partitioning and flow through ecosystems regulates land surface atmosphere CO 2 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 13CO 2 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 capturingmore » 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. 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 CO 2 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 13CO 2 label from the atmosphere through foliage, phloem, roots or surface soil CO 2 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 of detailed evaluations of CLM4, paired with intensive field manipulations, can help to identify model strengths and weaknesses, model uncertainties, and additional observations necessary for future model development.« less

Material appearance acquisition from a single image

NASA Astrophysics Data System (ADS)

Zhang, Xu; Cui, Shulin; Cui, Hanwen; Yang, Lin; Wu, Tao

2017-01-01

The scope of this paper is to present a method of material appearance acquisition(MAA) from a single image. In this paper, material appearance is represented by spatially varying bidirectional reflectance distribution function(SVBRDF). Therefore, MAA can be reduced to the problem of recovery of each pixel's BRDF parameters from an original input image, which include diffuse coefficient, specular coefficient, normal and glossiness based on the Blinn-Phone model. In our method, the workflow of MAA includes five main phases: highlight removal, estimation of intrinsic images, shape from shading(SFS), initialization of glossiness and refining SVBRDF parameters based on IPOPT. The results indicate that the proposed technique can effectively extract the material appearance from a single image.

The shady side of solar protection.

PubMed

Parsons, P G; Neale, R; Wolski, P; Green, A

1998-04-06

To determine the value of shade in protecting humans from solar ultraviolet (UV) radiation. Measurement with photometers of protection factors for ultraviolet B radiation (UVB) and for total solar radiation for different types of trees and other structures during the summer months (1995-1997) in south-east Queensland. (The protection ratio is the ratio of the intensity of UVB or total solar radiation in direct sunlight to that in shade.) For summer sun at midday, the mean (SD) UV protection ratio for the shade of trees (n = 65) was 4.21 (1.36) on a horizontal surface and 1.33 (0.30) on a vertical surface. In contrast, the mean (SD) protection ratio for total solar energy (primarily infrared) was much higher (12.1 [1.4]). Trees common in recreational areas in Australia (eucalypts: UV protection ratio, 3.52 [0.79]; Norfolk Island pines: UV protection ratio, 3.72 [0.98]) offered reduced protection compared with trees with more dense foliage (UV protection ratio, 5.48 [1.44]). Over a whole day, measurement of shade by trees and other structures showed that the UV protection ratio was lower in the morning and afternoon. Shade from awnings, buildings and hats gave similar results to those for trees. Both at midday and over a whole day satisfactory protection (UV protection ratio > 15) was obtained only in shade which eliminated exposure to the sky as well as to direct sunlight; for example, in thickly wooded areas and under low, widely overhanging structures. Most forms of shade, while useful, offer people insufficient protection from solar UV. A fair-skinned person sheltering under a tree could suffer sunburn after less than one hour. There is a need for appropriate design of structural shade, use of other solar protection measures in conjunction with shade, and research on behavioural responses to shade.

Real-time Supervised Detection of Pink Areas in Dermoscopic Images of Melanoma: Importance of Color Shades, Texture and Location

PubMed Central

Kaur, Ravneet; Albano, Peter P.; Cole, Justin G.; Hagerty, Jason; LeAnder, Robert W.; Moss, Randy H.; Stoecker, William V.

2015-01-01

Background/Purpose Early detection of malignant melanoma is an important public health challenge. In the USA, dermatologists are seeing more melanomas at an early stage, before classic melanoma features have become apparent. Pink color is a feature of these early melanomas. If rapid and accurate automatic detection of pink color in these melanomas could be accomplished, there could be significant public health benefits. Methods Detection of three shades of pink (light pink, dark pink, and orange pink) was accomplished using color analysis techniques in five color planes (red, green, blue, hue and saturation). Color shade analysis was performed using a logistic regression model trained with an image set of 60 dermoscopic images of melanoma that contained pink areas. Detected pink shade areas were further analyzed with regard to the location within the lesion, average color parameters over the detected areas, and histogram texture features. Results Logistic regression analysis of a separate set of 128 melanomas and 128 benign images resulted in up to 87.9% accuracy in discriminating melanoma from benign lesions measured using area under the receiver operating characteristic curve. The accuracy in this model decreased when parameters for individual shades, texture, or shade location within the lesion were omitted. Conclusion Texture, color, and lesion location analysis applied to multiple shades of pink can assist in melanoma detection. When any of these three details: color location, shade analysis, or texture analysis were omitted from the model, accuracy in separating melanoma from benign lesions was lowered. Separation of colors into shades and further details that enhance the characterization of these color shades are needed for optimal discrimination of melanoma from benign lesions. PMID:25809473

Accurate shade image matching by using a smartphone camera.

PubMed

Tam, Weng-Kong; Lee, Hsi-Jian

2017-04-01

Dental shade matching by using digital images may be feasible when suitable color features are properly manipulated. Separating the color features into feature spaces facilitates favorable matching. We propose using support vector machines (SVM), which are outstanding classifiers, in shade classification. A total of 1300 shade tab images were captured using a smartphone camera with auto-mode settings and no flash. The images were shot at angled distances of 14-20cm from a shade guide at a clinic equipped with light tubes that produced a 4000K color temperature. The Group 1 samples comprised 1040 tab images, for which the shade guide was randomly positioned in the clinic, and the Group 2 samples comprised 260 tab images, for which the shade guide had a fixed position in the clinic. Rectangular content was cropped manually on each shade tab image and further divided into 10×2 blocks. The color features extracted from the blocks were described using a feature vector. The feature vectors in each group underwent SVM training and classification by using the "leave-one-out" strategy. The top one and three accuracies of Group 1 were 0.86 and 0.98, respectively, and those of Group 2 were 0.97 and 1.00, respectively. This study provides a feasible technique for dental shade classification that uses the camera of a mobile device. The findings reveal that the proposed SVM classification might outperform the shade-matching results of previous studies that have performed similarity measurements of ΔE levels or used an S, a*, b* feature set. Copyright © 2016 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

Shade tree diversity and aboveground carbon stocks in Theobroma cacao agroforestry systems: implications for REDD+ implementation in a West African cacao landscape.

PubMed

Dawoe, Evans; Asante, Winston; Acheampong, Emmanuel; Bosu, Paul

2016-12-01

The promotion of cacao agroforestry is one of the ways of diversifying farmer income and creating incentives through their inclusion in REDD+ interventions. We estimated the aboveground carbon stocks in cacao and shade trees, determined the floristic diversity of shade trees and explored the possibility of implementing REDD+ interventions in cacao landscapes. Using replicated multi-site transect approach, data were collected from nine 1-ha plots established on 5 km long transects in ten cacao growing districts in Ghana West Africa. Biomass of cacao and shade trees was determined using allometric equations. One thousand four hundred and one (1401) shade trees comprising 109 species from 33 families were recorded. Total number of species ranged from 34 to 49. Newbouldia laevis (Bignoniacea) was the most frequently occurring specie and constituted 43.2 % of all shade trees. The most predominant families were Sterculiaceae and Moraceae (10 species each), followed by Meliaceae and Mimosaceae (8 species each) and Caesalpiniacaea (6 species). Shannon diversity indices (H', H max and J') and species richness were low compared to other similar studies. Shade tree densities ranged from 16.2 ± 3.0 to 22.8 ± 1.7 stems ha -1 and differed significantly between sites. Carbon stocks of shade trees differed between sites but were similar in cacao trees. The average C stock in cacao trees was 7.45 ± 0.41 Mg C ha -1 compared with 8.32 ± 1.15 Mg C ha -1 in the shade trees. Cacao landscapes in Ghana have the potential of contributing to forest carbon stocks enhancement by increasing the stocking density of shade trees to recommended levels.

Real-time supervised detection of pink areas in dermoscopic images of melanoma: importance of color shades, texture and location.

PubMed

Kaur, R; Albano, P P; Cole, J G; Hagerty, J; LeAnder, R W; Moss, R H; Stoecker, W V

2015-11-01

Early detection of malignant melanoma is an important public health challenge. In the USA, dermatologists are seeing more melanomas at an early stage, before classic melanoma features have become apparent. Pink color is a feature of these early melanomas. If rapid and accurate automatic detection of pink color in these melanomas could be accomplished, there could be significant public health benefits. Detection of three shades of pink (light pink, dark pink, and orange pink) was accomplished using color analysis techniques in five color planes (red, green, blue, hue, and saturation). Color shade analysis was performed using a logistic regression model trained with an image set of 60 dermoscopic images of melanoma that contained pink areas. Detected pink shade areas were further analyzed with regard to the location within the lesion, average color parameters over the detected areas, and histogram texture features. Logistic regression analysis of a separate set of 128 melanomas and 128 benign images resulted in up to 87.9% accuracy in discriminating melanoma from benign lesions measured using area under the receiver operating characteristic curve. The accuracy in this model decreased when parameters for individual shades, texture, or shade location within the lesion were omitted. Texture, color, and lesion location analysis applied to multiple shades of pink can assist in melanoma detection. When any of these three details: color location, shade analysis, or texture analysis were omitted from the model, accuracy in separating melanoma from benign lesions was lowered. Separation of colors into shades and further details that enhance the characterization of these color shades are needed for optimal discrimination of melanoma from benign lesions. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Effects of elevated turbidity and nutrients on the net production of a tropical seagrass community

DOE Office of Scientific and Technical Information (OSTI.GOV)

Caldwell, J.W.

1985-01-01

Dredging effects on seagrass communities in the Florida Keys were examined by (1) comparing impacts on net production resulting from dredging and natural weather events, (2) determining changes in community photosynthetic efficiency, (3) evaluating shading and nutrient effects on net production, and (4) developing a systems dynamics model. Net community production was estimated during numerous meteorological and dredging events using the Odum-Hoskins oxygen technique in flow-through field microcosms. In other experiments, shading and nutrients (phosphorus, nitrate, and ammonia) were manipulated to simulate dredge plume conditions. The greatest depression in net community production resulted from severe thunderstorms and dredging events, respectively.more » In field microcosm experiments, significant interaction occurred between shading and nutrient concentration. The model of seagrass production was most sensitive to changes in nutrient-seagrass relationships, seagrass production estimates, and seagrass-light interactions. Recovery of seagrass biomass following numerous dredging events (3.5 years) was longer than that from the estimated total annual thunderstorms encountered (1 year) but shorter than recovery from hurricane events (4.1 years).« less

Thermal-Mechanical Stability of Single Crystal Oxide Refractive Concentrators for High-Temperature Solar Thermal Propulsion

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Jacobson, Nathan S.; Miller, Robert A.

1999-01-01

Single crystal oxides such as yttria-stabilized zirconia (Y2O3-ZrO2), yttrium aluminum garnet (Y3Al5O12, or YAG), magnesium oxide (MgO) and sapphire (Al2O3) are candidate refractive secondary concentrator materials for high temperature solar propulsion applications. However, thermo-mechanical reliability of these components in severe thermal environments during the space mission sun/shade transition is of great concern. Simulated mission tests are important for evaluating these candidate oxide materials under a variety of transient and steady-state heat flux conditions, and thus provide vital information for the component design. In this paper, a controlled heat flux thermal shock test approach is established for the single crystal oxide materials using a 3.0 kW continuous wave CO2 laser, with a wavelength 10.6 micron. Thermal fracture behavior and failure mechanisms of these oxide materials are investigated and critical temperature gradients are determined under various temperature and heating conditions. The test results show that single crystal sapphire is able to sustain the highest temperature gradient and heating-cooling rate, and thus exhibit the best thermal shock resistance, as compared to the yttria-stabilized zirconia, yttrium aluminum garnet and magnesium oxide.

Thermal-Mechanical Stability of Single Crystal Oxide Refractive Concentrators for High-Temperature Solar Thermal Propulsion

NASA Technical Reports Server (NTRS)

Zhu, Dongming; Jacobson, Nathan S.; Miller, Robert A.

1999-01-01

Single crystal oxides such as yttria-stabilized zirconia (Y2O3-ZrO2), yttrium aluminum garnet (Y3Al5O12, or YAG), magnesium oxide (MgO) and sapphire (Al2O3) are candidate refractive secondary concentrator materials for high temperature solar propulsion applications. However, thermo-mechanical reliability of these components in severe thermal environments during the space mission sun/shade transition is of great concern. Simulated mission tests are important for evaluating these candidate oxide materials under a variety of transient and steady-state heat flux conditions, and thus provide vital information for the component design. In this paper, a controlled heat flux thermal shock test approach is established for the single crystal oxide materials using a 3.0 kW continuous wave CO2 laser, with a wavelength 10.6 micron. Thermal fracture behavior and failure mechanisms of these oxide materials are investigated and critical temperature gradients are determined under various temperature and heating conditions. The test results show that single crystal sapphire is able to sustain the highest temperature gradient and heating-cooling rate, and thus exhibit the best thermal shock resistance, as compared to the yttria-stabilized zirconia, yttrium aluminum garnet, and magnesium oxide.

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. © 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.

Influence of dental resin material composition on cross-polarization-optical coherence tomography imaging

PubMed Central

Lammeier, Carmen; Li, YuPing; Lunos, Scott; Fok, Alex; Rudney, Joel

2012-01-01

Abstract. The purpose of this study was to investigate cross-polarization-optical coherence tomography (CP-OCT) signal attenuation through different resin material compositions. Four distinct composite systems were used: Filtek supreme ultra (FSU) (3M ESPE), IPS empress direct (EMD) (Ivoclar Vivadent), estelite sigma quick (SQK) (Tokuyama Dental), and Z100 (3M ESPE). Cross-sectional images of different composite-demineralized phantoms (n=108) were collected using a 1310-nm intraoral cross-polarization swept source OCT (CP-OCT) imaging system. %T quantified the CP-OCT signal attenuation. Scanning electron microscopy, transmission electron microscopy, and energy-dispersive x-ray spectrometer chemical analysis was utilized to determine how different matrix/filler compositions affected attenuation of the near infrared (NIR) signal. CP-OCT imaging of dental resin composites showed enormous variation in signal attenuation. For each of our composite systems, there was not a consistent attenuation difference in the NIR signal for A to D shades. The four composites had similar measured backscattering values but attenuated the overall signal to different degrees. When comparing the A2 shades between the four different composite systems, the order of highest to lowest of %T was EMD>Z100, FSU>SQK (ANOVA, Tukey, p<0.0001). As a result, we demonstrate the importance of understanding how the constituents of composite materials affect CP-OCT signal attenuation. PMID:23224001

Influence of dental resin material composition on cross-polarization-optical coherence tomography imaging

NASA Astrophysics Data System (ADS)

Lammeier, Carmen; Li, YuPing; Lunos, Scott; Fok, Alex; Rudney, Joel; Jones, Robert S.

2012-10-01

The purpose of this study was to investigate cross-polarization-optical coherence tomography (CP-OCT) signal attenuation through different resin material compositions. Four distinct composite systems were used: Filtek supreme ultra (FSU) (3M ESPE), IPS empress direct (EMD) (Ivoclar Vivadent), estelite sigma quick (SQK) (Tokuyama Dental), and Z100 (3M ESPE). Cross-sectional images of different composite-demineralized phantoms (n=108) were collected using a 1310-nm intraoral cross-polarization swept source OCT (CP-OCT) imaging system. %T quantified the CP-OCT signal attenuation. Scanning electron microscopy, transmission electron microscopy, and energy-dispersive x-ray spectrometer chemical analysis was utilized to determine how different matrix/filler compositions affected attenuation of the near infrared (NIR) signal. CP-OCT imaging of dental resin composites showed enormous variation in signal attenuation. For each of our composite systems, there was not a consistent attenuation difference in the NIR signal for A to D shades. The four composites had similar measured backscattering values but attenuated the overall signal to different degrees. When comparing the A2 shades between the four different composite systems, the order of highest to lowest of %T was EMD>Z100, FSU>SQK (ANOVA, Tukey, p<0.0001). As a result, we demonstrate the importance of understanding how the constituents of composite materials affect CP-OCT signal attenuation.

Analysis on energy use in reuse cement silo for campus building

NASA Astrophysics Data System (ADS)

Fidiya Nugrahani, Elita; Winda Murti, Izzati; Arifianti, Qurrotin M. O.

2018-03-01

Semen Gresik, the first cement factory in Indonesia owned by the government was operated since 1957 and stopped the operation around 1997. The owner, PT. Semen Indonesia (Persero) intended to reuse cement factory for the campus building, Universitas Internasional Semen Indonesia (UISI). This research proposed to analyze the future Energy Use Intensity (EUI) and recommendation energy efficiency in renovating silo through simulation. The result of future EUI in existing building was 234 kWh/m2.year. The scenarios created to reduce energy use in six sectors: window shades, window material, infiltration, daylighting, plug load, air-conditioning and operation schedule. The lowest EUI estimated at 98.27 by use 2/3 window shades, triple low emission window glass, lighting efficiency at 3.23 W/m2, maximize daylighting and occupancy control, minimize infiltration to 0.17 ACH, and 12/5 for operation schedule.

VALIDATING the Accuracy of Sighten's Automated Shading Tool

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

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

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

Interior shadings for office indoor visual comfort in humid climate region

NASA Astrophysics Data System (ADS)

Dinapradipta, Asri; Sudarma, Erwin; Defiana, Ima; Erwindi, Collinthia

2018-03-01

As part of the fenestration system, the interior shadings have also a role to control the indoor environment to maintain indoor visual comfort. As the occupants have personal access to control these, their control behavior then, might enhance or even worsen indoor comfort performance. The controlling behavior might not only influence indoor comfort performance but can also indicate the success or failure of interior shading as a control device element. This paper is intended to report control behavior patterns, as represented by the variety of the slats’ openings of two types of interior shading i.e. Venetian and Vertical blinds and to analyze these on the concurrent impacts to indoor office building’s indoor illuminance and luminance distribution. The purpose of this research is to figure out the shading control patterns as well as to examine the effectiveness of these two types of interior shadings to control indoor visual environment. This study is a quantitative research using experimentation on the slats’ opening of two types of shadings at two identical office rooms. The research results suggested that both types of blinds seem unsuitable for gaining proper illumination values at work planes in humid tropics area. However, these shadings demonstrate good performance for luminance distribution except for that of the closed Venetian blinds.

Evaluating poverty grass (Danthonia spicata) for golf courses in the Midwest

Treesearch

Nadia E. Navarrete-Tindall; J.W. Van Sambeek

2010-01-01

Poverty grass (Danthonia spicata (L.) P. beauv. Ex Roem & Schult. ) results presented here are part of ongoing studies to evaluate its adaptation for golf courses as part of low maintenance natural communities at Lincoln University of Missouri. Because its natural adaptation to shade and poor soils, poverty grass could be established in golf...

Minimally Invasive Dentistry: A Conservative Approach to Smile Makeover.

PubMed

Rosenberg, Jeffrey M

2017-01-01

The concept of minimally invasive dentistry is based on preserving tooth structure, especially enamel. A conservative method to treat discolored teeth that have diastemas is a freehand additive technique using composite resin. While selecting the correct shade of resin can be challenging, newer composite resin formulations are being developed with optical properties that enable the material to more effectively blend into the dentition. This case report describes the use of conservative approaches and materials to treat discolored, unevenly spaced teeth and restore harmony and balance to a patient's smile.

The effects of shade on performance, carcass classes and behaviour of heat-stressed feedlot cattle at the finisher phase.

PubMed

Blaine, K L; Nsahlai, Ignatius Verla

2011-03-01

The study aimed to determine the impact of shade on the performance, carcass class and behaviour using 146 crossbred steers and bulls during the finishing phase on a commercial feedlot in February. Treatments were (1) shade and (2) no shade. Average daily gain (ADG), DMI, and feed efficiency were measured, and hot carcass weight (HCW) and grades were collected at slaughter. The proportion of animals within a pen engaged in various behavioural activities (standing, lying, feeding and panting) was recorded. Five randomly selected individual animals per treatment were monitored every 2 min between 0700 and 1600 hours to determine the time spent on each of the above activities. Shade improved the final body weight (P < 0.0001), ADG (P = 0.079), and HCW by 8.33 kg (P < 0.05). Shade increased (P < 0.05) the feeding activity but decreased (P < 0.05) panting behaviour. Shade conferred an economic benefit of R2.03 head(-1)week(-1), and thus would reduce heat stress and increase the feedlot profitability.

Improved color matching of metal ceramic restorations. Part II: Procedures for visual communication.

PubMed

Sorensen, J A; Torres, T J

1987-12-01

Most ceramic restorations are fabricated in a location remote from the dental office. Successful fabrication of matching life-like ceramic restorations necessitates a collaborative effort between the dentist and the ceramist. To meet the demands for visual communication of shade and surface texture, the following steps are recommended. 1. A means of communicating and recording surface texture that facilitates blending the restorations with the natural dentition should be used. 2. The system should use an esthetics prescription form that functions with the Shade Indicator Chart system to relate the shade of opaque, body, and incisal porcelains and their arrangement to the ceramist. 3. An easily made identification mold to form shade tabs is needed. 4. Identification shade tabs should be made to verify and document shade formulations selected with the Shade Indicator Chart system. 5. Methods for precisely mapping and reproducing individual characterization patterns are needed. This information permits the visualization of the end result, allowing the artistic expression of the ceramist to create vital-appearing restorations intrinsically and in harmony with the natural dentition.

Surface composition of Mars: A Viking multispectral view

NASA Technical Reports Server (NTRS)

Adams, John B.; Smith, Milton O.; Arvidson, Raymond E.; Dale-Bannister, Mary; Guinness, Edward A.; Singer, Robert; Adams, John B.

1987-01-01

A new method of analyzing multispectral images takes advantage of the spectral variation from pixel to pixel that is typical for natural planetary surfaces, and treats all pixels as potential mixtures of spectrally distinct materials. For Viking Lander images, mixtures of only three spectral end members (rock, soil, and shade) are sufficient to explain the observed spectral variation to the level of instrumental noise. It was concluded that a large portion of the Martian surface consists of only two spectrally distinct materials, basalt and palgonitic soil. It is emphasized, however, that as viewed through the three broad bandpasses of Viking Orbiter, other materials cannot be distinguished from the mixtures.

Plant Strategies for Enhancing Access to Sunlight.

PubMed

Fiorucci, Anne-Sophie; Fankhauser, Christian

2017-09-11

Light is a vital resource for plants, which compete for it particularly in dense communities. Plants have multiple photosensory receptors to detect the presence of competitors and thereby adjust their growth and developmental strategies accordingly. Broadly speaking, plants fall into two categories depending on their response to shading by leaves: shade tolerant or shade avoiding. Here, we describe the photoperception mechanisms and the growth responses elicited by the neighboring vegetation in shade-avoiding plants, focusing on Arabidopsis thaliana, where these responses are best understood. The type of response depends on plant density, ranging from neighbor detection modulating growth in anticipation of future shading to the response to canopy shade where light resources are limiting. These diverse environments are sensed by various photoreceptors, and we will describe our current understanding of signal integration triggered by distinct light cues in diverse light conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

Color change of composite resins subjected to accelerated artificial aging.

PubMed

Tornavoi, Denise Cremonezzi; Agnelli, José Augusto Marcondes; Panzeri, Heitor; Dos Reis, Andréa Cândido

2013-01-01

The aim of this study was to evaluate the influence of accelerated artificial aging (AAA) on the color change of composite resins used in dentistry. Three composite resins were evaluated: Two microhybrids and one hybrid of higher viscosity, with different amounts and sizes of filler particles, shades C2 and B2. A total of 54 specimens were obtained (18 for each composite resin), made of a Teflon matrix (15 mm in diameter and 2 mm in height). The color measurements were obtained with a Spectrophotometer, (PCB 6807 BYK Gardner) before and after AAA. Data were submitted to the Kolmogorov-Smirnov test (α >0.05), ANOVA and Tukey test (α <0.05). After statistical analysis, the color difference among composite resins with the same shades was analyzed. All composite resins showed unacceptable color changes after AAA (ΔE > 3). Considering the variable ∆E, it was observed that the color tone C2 was already statistically different for the microhybrid composite resin prior to AAA (P < 0.05) and in shade B2 for hybrid of higher viscosity and microhybrid with barium glass fluoride aluminum and silica dioxide (P < 0.01). After this process, a statistically significant difference was observed only for shade B2 between microhybrid composite resins (P < 0.01) and for hybrid of higher viscosity and microhybrid with barium glass fluoride aluminum and silica dioxide (P < 0.05). Regarding the color difference within a same composite resin group, before aging the composite resin hybrid of higher viscosity B2 showed the highest color variation rate and microhybrid with zirconium/silica C2 showed the lowest. All composite resins presented unacceptable color changes after 382 h of aging and different composite resins with same hue, presented different colors before being subjected to the aging process (B2 and C2) and after (B2). It was also observed color difference within a group of the same composite resin and same hue.

Variation of the Phytochemical Constituents and Antioxidant Activities of Zingiber officinale var. rubrum Theilade Associated with Different Drying Methods and Polyphenol Oxidase Activity.

PubMed

Ghasemzadeh, Ali; Jaafar, Hawa Z E; Rahmat, Asmah

2016-06-17

The effects of different drying methods (freeze drying, vacuum oven drying, and shade drying) on the phytochemical constituents associated with the antioxidant activities of Z. officinale var. rubrum Theilade were evaluated to determine the optimal drying process for these rhizomes. Total flavonoid content (TFC), total phenolic content (TPC), and polyphenol oxidase (PPO) activity were measured using the spectrophotometric method. Individual phenolic acids and flavonoids, 6- and 8-gingerol and shogaol were identified by ultra-high performance liquid chromatography method. Ferric reducing antioxidant potential (FRAP) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays were used for the evaluation of antioxidant activities. The highest reduction in moisture content was observed after freeze drying (82.97%), followed by vacuum oven drying (80.43%) and shade drying (72.65%). The highest TPC, TFC, and 6- and 8-shogaol contents were observed in samples dried by the vacuum oven drying method compared to other drying methods. The highest content of 6- and 8-gingerol was observed after freeze drying, followed by vacuum oven drying and shade drying methods. Fresh samples had the highest PPO activity and lowest content of flavonoid and phenolic acid compounds compared to dried samples. Rhizomes dried by the vacuum oven drying method represent the highest DPPH (52.9%) and FRAP activities (566.5 μM of Fe (II)/g DM), followed by freeze drying (48.3% and 527.1 μM of Fe (II)/g DM, respectively) and shade drying methods (37.64% and 471.8 μM of Fe (II)/g DM, respectively) with IC50 values of 27.2, 29.1, and 34.8 μg/mL, respectively. Negative and significant correlations were observed between PPO and antioxidant activity of rhizomes. Vacuum oven dried rhizomes can be utilized as an ingredient for the development of value-added food products as they contain high contents of phytochemicals with valuable antioxidant potential.

A field measure of the shade fraction

NASA Technical Reports Server (NTRS)

Gillespie, Alan R.; Smith, Milton O.; Sabol, Donald E.

1992-01-01

'Shade' has a technical definition peculiar to linear spectral mixture analysis of imaging spectrometer data: it is the reduction in radiance from a surface due to lighting conditions and geometry, and includes topographic shading described by photometric functions as well as shadowing at all scales. 'Shade' is an important constituent of nearly all remotely sensed images, and is one endmember resolved in spectral mixture analysis, where it is represented as a fraction of the measured radiance and a characteristic spectrum. This spectrum is typically the null vector, provided the data have been corrected for atmospheric and instrument effects: i.e., 'shade' is the radiance from an ideal black surface. In topographic shading, irradiance is reduced - typically in proportion to cos(i), where i (incidence angle) is the angle between the sun and the local surface normal vectors. Therefore, the radiance is lowered by a multiplicative factor. Shadowing occurs when i is greater than 90 deg, or when sunlight is blocked by adjacent high terrain; the only irradiance is down-welling skylight and bounce light from adjacent terrain. In spectral mixture analysis, 'shade' is regarded as an additive term. In this regard, it is an accurate description of the proportion of a scene that consists of ideal shadows ('checkerboard mixing'); however, 'shade' represents the multiplicative cos(i) factor as well, as here it should be interpreted as the proportion of shadow that would darken the scene an equivalent amount. In either case, the 'shade' fraction is lessened by adjacency effects, because the scene has a non-zero reflectivity instead of the ideal black surface generally assumed.

Differential responses of double petal and multi petal jasmine to shading: I. Photosynthetic characteristics and chloroplast ultrastructure.

PubMed

Deng, Yanming; Li, Congcong; Shao, Qingsong; Ye, Xiaoqing; She, Jianming

2012-06-01

A double petal (DP) and a multi petal (MP) type jasmine (Jasminum sambac Ait.) growth and flowering was known largely affected by different levels of irradiance. Here, our objective was to determine the effects of shade on photosynthesis related characteristics and chloroplast ultrastructure of these two types. In both types, net photosynthetic rate (Pn), stomatal conductance (g(s)) and transpiration rate increased with decreasing irradiance from 100% to 20%, while both maximum and variable fluorescence showed a steady increase, and photochemical and nonphotochemical quenching indexes declined. At each conducted time, chlorophyll a, b and carotenoids contents in DP type shaded leaves increased whereas those in MP type decreased at 5% irradiance (considered as extreme shade). The maximum photochemical efficiency of photosystem II of DP plants showed subtle changes but that of MP plants declined by shading thereafter 21 days of treatment. Observation of chloroplast ultrastructure showed its best development in the leaves of DP and MP types mostly from 50% to 20% irradiance (considered as weak and moderate shade, respectively). At each shade treatment, Pn, g(s) and water use efficiency of DP-jasmine were always higher than those of MP-jasmine, thus the shade tolerance ability of the former was higher than that of the latter. The results showed that full sunlight and 5% natural irradiance caused photoinhibition and light deficiency of jasmine plants respectively, and modulating chloroplast development by the more numbers of thylakoids and grana to contain more photosynthetic pigments is an important shade tolerance mechanism of DP type. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

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.

Light-attenuating effect of dentin on the polymerization of light-activated restorative resins.

PubMed

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

2004-12-01

The light-attenuating effect of dentin on the mechanical properties of light-activated composite resins was evaluated using a simple experimental filter. The filter was designed to simulate the light transmittance and light diffusion characteristics of 1.0-mm thick dentin. The depth of cure, surface hardness, and flexural strength for 13 shades of three light-activated restorative resins were examined. These resins were cured either using direct irradiation with a light source, or indirect irradiation through the filter. The attenuation of light intensity by 1.0-mm thick dentin reached 85-90% in the 400-550 nm wavelength region. For all materials, the values of depth of cure, surface hardness on the top and bottom surfaces, and flexural strength of specimens irradiated indirectly through the simulated 1.0-mm thick dentin filter decreased by 37-60%, 16-55%, 50-83%, and 44-82% in comparison with those by direct irradiation, respectively. Recovery from mechanical properties' reduction was achieved when materials were irradiated 1.5-4 times longer than the standard irradiation time.

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-tolerant broadleaves. The results of our study suggest that the combinations of plant attributes enhancing growth under high light vary with shade tolerance, but differ between leaf habit groups. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Evaluating visibility of age spot and freckle based on simulated spectral reflectance distribution and facial color image

NASA Astrophysics Data System (ADS)

Hirose, Misa; Toyota, Saori; Tsumura, Norimichi

2018-02-01

In this research, we evaluate the visibility of age spot and freckle with changing the blood volume based on simulated spectral reflectance distribution and the actual facial color images, and compare these results. First, we generate three types of spatial distribution of age spot and freckle in patch-like images based on the simulated spectral reflectance. The spectral reflectance is simulated using Monte Carlo simulation of light transport in multi-layered tissue. Next, we reconstruct the facial color image with changing the blood volume. We acquire the concentration distribution of melanin, hemoglobin and shading components by applying the independent component analysis on a facial color image. We reproduce images using the obtained melanin and shading concentration and the changed hemoglobin concentration. Finally, we evaluate the visibility of pigmentations using simulated spectral reflectance distribution and facial color images. In the result of simulated spectral reflectance distribution, we found that the visibility became lower as the blood volume increases. However, we can see that a specific blood volume reduces the visibility of the actual pigmentations from the result of the facial color images.

Species abundance and potential biological control services in shade vs. sun coffee in Puerto Rico

USGS Publications Warehouse

Borkhataria, Rena R.; Collazo, Jaime A.; Groom, Martha J.

2012-01-01

Birds, lizards and insects were surveyed in three sun and three shade coffee plantations in Puerto Rico to provide a comprehensive comparison of biodiversity between plantations types and to identify potential interrelationships (e.g., biological or natural control services) between members of each taxon and coffee pests. Abundance of avian species, including insectivorous species, was significantly higher in shade coffee. Anolis cristatellus and A. stratulus were significantly more abundant in sun plantations whereas A. gundlachi and A. evermanni were detected more frequently in shade plantations. Insects in the orders Coleoptera, Diptera, Hemiptera, Hymenoptera, Lepidoptera, Neuroptera, and Psocoptera were significantly more abundant in shade coffee, while orthopterans were more abundant in sun. The coffee leaf miner (Leucoptera coffeela) and the flatid planthopper (Petrusa epilepsis) did not differ significantly between plantation types, nor did the abundance of the wasp complex that parasitizes the coffee leaf miner. These findings confirmed that shade plantations harbor a wide array of elements of biodiversity; but sun plantations may also harbor many elements of biodiversity, and in some cases, in higher abundance than in shade plantations.

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. © 2010 Entomological Society of America

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.

Studies of machinable ceramics for dental applications. 1. Color analysis.

PubMed

Taira, M; Wakasa, K; Yamaki, M; Tanaka, N; Shintani, H

1989-12-01

Machinable ceramics that can be cut and even lathed have recently been developed in industry. As a first step in evaluating the feasibility of such ceramics in dentistry, eight machinable ceramics were examined for color using the Vita shade guide and a chroma-meter reflectance instrument. We discovered that the studied machinable ceramics varied significantly from the Vita shade guide by the color difference vector, delta E. These machinable ceramics appeared very white and strongly opaque due to their high brightness (L*) values. For intra-oral applications, we expect that L* values of machinable ceramics will be reduced by modification of their microstructures, including their matrix and dispersed phases, while their excellent machinability due to the cleavage of dispersed crystals should be retained.

Fifty Shades of Unsaid: Women’s Explicit and Implicit Attitudes Towards Sexual Morality

PubMed Central

Lanciano, Tiziana; Soleti, Emanuela; Guglielmi, Francesca; Mangiulli, Ivan; Curci, Antonietta

2016-01-01

The movie Fifty Shades of Grey has created a great deal of controversy which has reignited the debate on unusual and alternative sexual practices such as bondage. Erotophobic individuals have negative affect towards the type of sexual libertinism conveyed by the movie, while erotophilic persons have a positive attitude and emotional feelings towards this kind of sexual emancipation. Using the Implicit Association Test, this study aimed to explore the extent to which there is a difference in women's attitudes towards sexual morality on an explicit and implicit level. Our findings found that erotophobic and erotophilic women differed only on an explicit level of sex guilt and moral evaluation, while no difference in the implicit measure was found. PMID:27872666

Evaluation of the Efficacy and Color Stability of Two Different At-Home Bleaching Systems on Teeth of Different Shades: A Randomized Controlled Clinical Trial.

PubMed

Aka, Betül; Celik, Esra Uzer

2017-09-01

This randomized controlled clinical trial compared the bleaching efficacy of two different at-home bleaching systems on teeth of different shades and their color stability after a 6-month follow-up. Ninety-two patients (777 teeth) were randomly divided into three groups: (a) negative control, (b) patients treated with a custom-made tray containing 10% carbamide peroxide (10% CP/PF) (Opalescence PF), and (c) patients treated with a pre-loaded tray containing 6% hydrogen peroxide (6% HP/Go) (Opalescence Go). Teeth in all groups were divided into three sub-groups according to the VITA Classic Shade Guide: light (A1-C1), medium dark (C2-B3), and dark (A3.5-C4). Bleaching systems were performed in accordance with manufacturers' instructions for 14 days. The color values were measured at the baseline, 10 days and 14 days of bleaching, 2 weeks, and 6 months after bleaching. Three-way ANOVA and Mann-Whitney U tests were used for statistical analysis (α = 0.05). Irrespective of original shade, both bleaching groups showed significantly higher ΔE* values than the control groups, and the ΔE* values were significantly higher in the 10% CP/PF groups than those in the 6% HP/Go groups (p < 0.05). In both bleaching systems, the dark teeth showed higher ΔE* values than the light teeth (p < 0.05). The ΔE* values decreased significantly only in the 10% CP/PF groups after 6 months (p < 0.05). Both bleaching agents produced a bleaching effect, but 10% CP/PF was more effective. A pre-loaded tray system may be used for dental bleaching, but it is still less effective than conventional a 10% carbamide peroxide system, irrespective of the initial shade. (J Esthet Restor Dent 29:325-338, 2017). © 2017 Wiley Periodicals, Inc.

Tree cover at fine and coarse spatial grains interacts with shade tolerance to shape plant species distributions across the Alps

PubMed Central

Nieto-Lugilde, Diego; Lenoir, Jonathan; Abdulhak, Sylvain; Aeschimann, David; Dullinger, Stefan; Gégout, Jean-Claude; Guisan, Antoine; Pauli, Harald; Renaud, Julien; Theurillat, Jean-Paul; Thuiller, Wilfried; Van Es, Jérémie; Vittoz, Pascal; Willner, Wolfgang; Wohlgemuth, Thomas; Zimmermann, Niklaus E.; Svenning, Jens-Christian

2015-01-01

The role of competition for light among plants has long been recognised at local scales, but its importance for plant species distributions at larger spatial scales has generally been ignored. Tree cover modifies the local abiotic conditions below the canopy, notably by reducing light availability, and thus, also the performance of species that are not adapted to low-light conditions. However, this local effect may propagate to coarser spatial grains, by affecting colonisation probabilities and local extinction risks of herbs and shrubs. To assess the effect of tree cover at both the plot- and landscape-grain sizes (approximately 10-m and 1-km), we fit Generalised Linear Models (GLMs) for the plot-level distributions of 960 species of herbs and shrubs using 6,935 vegetation plots across the European Alps. We ran four models with different combinations of variables (climate, soil and tree cover) at both spatial grains for each species. We used partial regressions to evaluate the independent effects of plot- and landscape-grain tree cover on plot-level plant communities. Finally, the effects on species-specific elevational range limits were assessed by simulating a removal experiment comparing the species distributions under high and low tree cover. Accounting for tree cover improved the model performance, with the probability of the presence of shade-tolerant species increasing with increasing tree cover, whereas shade-intolerant species showed the opposite pattern. The tree cover effect occurred consistently at both the plot and landscape spatial grains, albeit most strongly at the former. Importantly, tree cover at the two grain sizes had partially independent effects on plot-level plant communities. With high tree cover, shade-intolerant species exhibited narrower elevational ranges than with low tree cover whereas shade-tolerant species showed wider elevational ranges at both limits. These findings suggest that forecasts of climate-related range shifts for herb and shrub species may be modified by tree cover dynamics. PMID:26290621

Computed gray levels in multislice and cone-beam computed tomography.

PubMed

Azeredo, Fabiane; de Menezes, Luciane Macedo; Enciso, Reyes; Weissheimer, Andre; de Oliveira, Rogério Belle

2013-07-01

Gray level is the range of shades of gray in the pixels, representing the x-ray attenuation coefficient that allows for tissue density assessments in computed tomography (CT). An in-vitro study was performed to investigate the relationship between computed gray levels in 3 cone-beam CT (CBCT) scanners and 1 multislice spiral CT device using 5 software programs. Six materials (air, water, wax, acrylic, plaster, and gutta-percha) were scanned with the CBCT and CT scanners, and the computed gray levels for each material at predetermined points were measured with OsiriX Medical Imaging software (Geneva, Switzerland), OnDemand3D (CyberMed International, Seoul, Korea), E-Film (Merge Healthcare, Milwaukee, Wis), Dolphin Imaging (Dolphin Imaging & Management Solutions, Chatsworth, Calif), and InVivo Dental Software (Anatomage, San Jose, Calif). The repeatability of these measurements was calculated with intraclass correlation coefficients, and the gray levels were averaged to represent each material. Repeated analysis of variance tests were used to assess the differences in gray levels among scanners and materials. There were no differences in mean gray levels with the different software programs. There were significant differences in gray levels between scanners for each material evaluated (P <0.001). The software programs were reliable and had no influence on the CT and CBCT gray level measurements. However, the gray levels might have discrepancies when different CT and CBCT scanners are used. Therefore, caution is essential when interpreting or evaluating CBCT images because of the significant differences in gray levels between different CBCT scanners, and between CBCT and CT values. Copyright © 2013 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

Is shade beneficial for mediterranean shrubs experiencing periods of extreme drought and late-winter frosts?

PubMed

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

2008-12-01

Plants are naturally exposed to multiple, frequently interactive stress factors, most of which are becoming more severe due to global change. Established plants have been reported to facilitate the establishment of juvenile plants, but net effects of plant-plant interactions are difficult to assess due to complex interactions among environmental factors. An investigation was carried out in order to determine how two dominant evergreen shrubs (Quercus ilex and Arctostaphylos uva-ursi) co-occurring in continental, Mediterranean habitats respond to multiple abiotic stresses and whether the shaded understorey conditions ameliorate the negative effects of drought and winter frosts on the physiology of leaves. Microclimate and ecophysiology of sun and shade plants were studied at a continental plateau in central Spain during 2004-2005, with 2005 being one of the driest and hottest years on record; several late-winter frosts also occurred in 2005. Daytime air temperature and vapour pressure deficit were lower in the shade than in the sun, but soil moisture was also lower in the shade during the spring and summer of 2005, and night-time temperatures were higher in the shade. Water potential, photochemical efficiency, light-saturated photosynthesis, stomatal conductance and leaf 13C composition differed between sun and shade individuals throughout the seasons, but differences were species specific. Shade was beneficial for leaf-level physiology in Q. ilex during winter, detrimental during spring for both species, and of little consequence in summer. The results suggest that beneficial effects of shade can be eclipsed by reduced soil moisture during dry years, which are expected to be more frequent in the most likely climate change scenarios for the Mediterranean region.

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

Rationale, design, and baseline data of a cross-national randomized trial on the effect of built shade in public parks for sun protection.

PubMed

Buller, David B; Dobbinson, Suzanne; English, Dallas R; Wakefield, Melanie; Buller, Mary Klein

2017-04-01

Environments can be structured to reduce solar ultraviolet radiation (UV) exposure to prevent skin cancer. A prospective randomized trial is being conducted to test whether introducing shade sails in passive recreation areas (PRAs) in public parks will increase use and decrease UV exposure in the shaded compared to unshaded PRAs. Shade effects will be compared between Melbourne, Australia and Denver, USA. The trial enrolled 145 public parks with PRAs suitable for shade construction and randomized parks to intervention or control in a 1:3 ratio. Use of PRAs and UV levels were recorded at each park by trained observers during 30-minute periods on four weekend days in each of two summers (pretest and posttest). Shade sails were constructed between the summers. Given low numbers of users at pretest, the outcome measure was modified to use of the PRA (use vs. no use) and unit of analysis to the individual observation. Observations (n=580) occurred on average 29days from the summer solstice and 55min from solar noon in warm weather (mean=26.2°C) with some cloud cover but only slight or no wind. Typically, PRAs had benches and picnic tables and were located near playgrounds. PRAs were in use during 13.3% of observations (mean=0.41 users). UV over 30-minutes at the PRA boundary (mean=3.2 standard erythemal dose [SED]) and center (mean=3.3 SED) was high. Shade for skin cancer prevention has been understudied. This study will address this gap by determining whether purpose-built shade structures promote greater use of shaded areas within public parks. Copyright © 2017 Elsevier Inc. All rights reserved.

Light compensation points in shade-grown seedlings of deciduous broadleaf tree species with different successional traits raised under elevated CO2.

PubMed

Kitao, M; Hida, T; Eguchi, N; Tobita, H; Utsugi, H; Uemura, A; Kitaoka, S; Koike, T

2016-01-01

We measured leaf photosynthetic traits in shade-grown seedlings of four tree species native to northern Japan, raised under an elevated CO2 condition, to investigate the effects of elevated CO2 on shade tolerance of deciduous broadleaf tree species with different successional traits. We considered Betula platyphylla var. japonica and Betula maximowicziana as pioneer species, Quercus mongolica var. crispula as a mid-successional species, and Acer mono as a climax species. The plants were grown under shade conditions (10% of full sunlight) in a CO2 -regulated phytotron. Light compensation points (LCPs) decreased in all tree species when grown under elevated CO2 (720 μmol·mol(-1) ), which were accompanied by higher apparent quantum yields but no photosynthetic down-regulation. LCPs in Q. mongolica and A. mono grown under elevated CO2 were lower than those in the two pioneer birch species. The LCP in Q. mongolica seedlings was not different from that of A. mono in each CO2 treatment. However, lower dark respiration rates were observed in A. mono than in Q. mongolica, suggesting higher shade tolerance in A. mono as a climax species in relation to carbon loss at night. Thus, elevated CO2 may have enhanced shade tolerance by lowering LCPs in all species, but the ranking of shade tolerance related to successional traits did not change among species under elevated CO2 , i.e. the highest shade tolerance was observed in the climax species (A. mono), followed by a gap-dependent species (Q. mongolica), while lower shade tolerance was observed in the pioneer species (B. platyphylla and B. maximowicziana). © 2015 German Botanical Society and The Royal Botanical Society of the Netherlands.

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, Martha 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.

Rationale, Design, and Baseline Data of a Cross-national Randomized Trial on the Effect of Built Shade in Public Parks for Sun Protection

PubMed Central

Buller, David B.; Dobbinson, Suzanne; English, Dallas R.; Wakefield, Melanie; Buller, Mary Klein

2017-01-01

Environments can be structured to reduce solar ultraviolet radiation (UV) exposure to prevent skin cancer. A prospective randomized trial is being conducted to test whether introducing shade sales in passive recreation areas (PRAs) in public parks will increase use and decrease UV exposure in the shaded compared to unshaded PRAs. Shade effects will be compared between Melbourne, Australia and Denver, USA. The trial enrolled 144 public parks with PRAs suitable for shade construction and randomized parks to intervention or control in a 1:3 ratio. Use of PRAs and UV levels were recorded at each park by trained observers during 30-minute periods on four weekend days in each of two summers (pretest and posttest). Shade sails were constructed between the summers. Given low numbers of users at pretest, the outcome measure was modified to use of the PRA (use v. no use) and unit of analysis to the individual observation. Observations (n=580) occurred on average 29 days from the summer solstice and 55 minutes from solar noon in warm weather (mean=26.2°C) with some cloud cover but only slight or no wind. Typically, PRAs had benches and picnic tables and were located near playgrounds. PRAs were in use during 13.3% of observations (mean=0.41 users). UV over 30-minutes at the PRA boundary (mean=3.2 standard erythemal dose [SED]) and center (mean=3.3 SED) was high. Shade for skin cancer prevention has been understudied. This study will address this gap by determining whether purpose-built shade structures promote greater use of shaded areas within public parks. PMID:28185996

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.

An evaluation of light intensity functions for determination of shaded reference stream metabolism.

PubMed

Zell, Chris; Hubbart, Jason A

2012-04-30

The performance of three single-station whole stream metabolism models were evaluated within three shaded, seasonally hypoxic, Missouri reference streams using high resolution (15-minute) dissolved oxygen (DO), temperature, and light intensity data collected during the summers (July-September) of 2006-2008. The model incorporating light intensity data consistently achieved a lower root mean square error (median RMSE = 0.20 mg L(-1)) relative to models assuming sinusoidal light intensity functions (median RMSE = 0.28 mg L(-1)) and constant diel temperature (median RMSE = 0.53 mg L(-1)). Incorporation of site-specific light intensity into metabolism models better predicted morning DO concentrations and exposure to hypoxic conditions in shaded study streams. Model choice significantly affected (p < 0.05) rate estimates for daily average photosynthesis. Low reaeration (pooled site mean 1.1 day(-1) at 20 °C) coupled with summer temperatures (pooled site mean = 25.8 °C) and low to moderate community respiration (site median 1.0-3.0 g O(2) m(-2) day(-1)) yielded diel dissolved oxygen concentrations near or below critical aquatic life thresholds in studied reference streams. Quantifying these process combinations in best-available or least-disturbed (i.e., reference) systems advances our understanding of regional dissolved oxygen expectations and informs environmental management policy. Additional research is warranted to better link landscape processes with distributed sources that contribute to community respiration. Copyright © 2011 Elsevier Ltd. All rights reserved.

Using a colorimeter to develop an intrinsic silicone shade guide for facial prostheses.

PubMed

Over, L M; Andres, C J; Moore, B K; Goodacre, C J; Muñoz, C A

1998-12-01

To determine if using CIE L*a*b* color measurements of white facial skin could be correlated to those of silicone shade samples that visually matched the skin. Secondly, to see if a correlation in color measurements could be achieved between the silicone shade samples and duplicated silicone samples made using a shade-guide color formula. A color booth was designed according to ASTM specifications, and painted using a Munsell Value 8 gray. A Minolta colorimeter was used to make facial skin measurements on 15 white adults. The skin color was duplicated using custom-shaded silicone samples. A 7-step wedge silicone shade guide was then fabricated, representing the commonly encountered thicknesses when fabricating facial prostheses. The silicone samples were then measured with the Minolta colorimeter. The readings were compared with the previous L*a*b* readings from the corresponding patient's skin measurements, and the relative color difference was then calculated. Silicone samples were fabricated and analyzed for three of the patients to determine if duplication of the visually matched silicone specimen was possible using the silicone color formula, and if the duplicates were visually and colorimetrically equivalent to each other. The color difference Delta E and chromaticity was calculated, and the data were analyzed using a coefficient-of-variation formula expressed by percent. A Pearson Product Moment Correlation Coefficient was performed to determine if a correlation existed between the skin and the silicone samples at the p < or = .05 level. The highest correlation was found in the b* dimension for silicone thicknesses of 1 to 4 mm. For silicone thicknesses of 6 to 10 mm, the highest correlation was found in the L* dimension. All three dimensions had positive correlations (R2 > 0), but only the 1-mm and 4-mm b* readings were very strong. Patient and silicone L*a*b* measurement results showed very little change in the a* axis, while the L* and b* measurements showed more change in their numbers, with changes in depth for all patient silicone samples. Delta E numbers indicated the lowest Delta E at the 1-mm depth and the highest Delta E at the 10-mm depth. All duplicated samples matched their original silicone samples to a degree that visual evaluation could not distinguish any color differences. Using volumetric measurements, a shade guide was developed for all 15 patients. There was good correlation between the patient's colorimeter measurements and the silicone samples, with the b* color dimension the most reproducible, followed by the L* and the a*. Silicone samples at 6, 8, and 10 mm matched the patient the best, and this study showed that silicone samples can be duplicated successfully if a good patient-silicone match is obtained. Rayon flocking fibers and liquid makeup are effective at matching facial prostheses and can be used to develop a simple shade guide for patient application.

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.

Effects of polishing on surface roughness, gloss, and color of resin composites.

PubMed

Hosoya, Yumiko; Shiraishi, Takanobu; Odatsu, Tetsuro; Nagafuji, Junichi; Kotaku, Mayumi; Miyazaki, Masashi; Powers, John M

2011-09-01

This study evaluated the effects of polishing on surface roughness, gloss, and color of regular, opaque, and enamel shades for each of three resin composites. Two-mm-thick resin disks made with Estelite Σ Quick, Clearfil Majesty, and Beautifil II were final polished with 180-, 1000-, and 3000-grit silicon carbide paper. Surface roughness, gloss, and color were measured one week after curing. Estelite Σ Quick had significantly lower roughness values and significantly higher gloss values as compared with Clearfil Majesty and Beautifil II. The effects of surface roughness and gloss on color (L*a*b*) differed among resin composites and by shade. Correlation coefficients between surface roughness and L*a*b* color factors were generally high for Clearfil Majesty, partially high (i.e., between roughness and L*) for Beautifil II, and low for Estelite Σ Quick. Correlation coefficients between gloss and L*a*b* color parameters were generally high for Beautifil II and low for Estelite Σ Quick and Clearfil Majesty. However, for all resin composites, the values of the color differences between 3000-grit and 180-grit polishing groups for all shades were imperceptible by the naked eye.

Radiometer footprint model to estimate sunlit and shaded components for row crops

USDA-ARS?s Scientific Manuscript database

This paper describes a geometric model for computing the relative proportion of sunlit vegetation, shaded vegetation, sunlit soil, and shaded soil appearing in a circular or elliptical radiometer footprint for row crops, where the crop rows were modeled as continuous ellipses. The model was validate...

Shade effects on growth, flowering, and fruit of apple

USDA-ARS?s Scientific Manuscript database

Light is a critical resource needed by plants for growth and reproduction. A major portion of the apple (Malus xdomestica Borkh.) tree’s canopy is subjected to shade during most daylight hours each day and such shade may affect productivity. The current research determined effects of morning, afte...

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…

Influence of shading on container-grown flowering dogwoods

USDA-ARS?s Scientific Manuscript database

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...

PowerFilm PowerShade Fixed Site Solar System Cost Reduction Plan

DTIC Science & Technology

2014-07-31

2337 230’^ St Ames, lA 50014 JL’Olt^lO:pi𔄁oq7 j pageii Executive summary Power film and its partners have developed a Generation II PowerShade...which meets or exceeds the goals of this development contract, increasing power and improving the ROI of the power shade significantly while improving a...number of the human factors. Comparing the Gen II 1.8 KW PowerShade to the equivalent power Gen I unit (Gen I Medium), The cost has been reduced

Scale model testing of drogues for free drifting buoys

NASA Technical Reports Server (NTRS)

Vachon, W. A.

1973-01-01

Instrumented model drogue tests were conducted in a ship model towing tank. The purpose of the tests was to observe and measure deployment and drag characteristics of such shapes as parachutes, crossed vanes, and window shades which may be employed in conjunction with free drifting buoys. Both Froude and Reynolds scaling laws were applied while scaling to full scale relative velocities of from 0 to 0.2 knots. A weighted window shade drogue is recommended because of its performance, high drag coefficient, simplicity, and low cost. Detailed theoretical performance curves are presented for parachutes, crossed vanes, and window shade drogues. Theoretical estimates of depth locking accuracy and buoy-induced dynamic loads pertinent to window shade drogues are presented as a design aid. An example of a window shade drogue design is presented.

Aircraft geometry verification with enhanced computer generated displays

NASA Technical Reports Server (NTRS)

Cozzolongo, J. V.

1982-01-01

A method for visual verification of aerodynamic geometries using computer generated, color shaded images is described. The mathematical models representing aircraft geometries are created for use in theoretical aerodynamic analyses and in computer aided manufacturing. The aerodynamic shapes are defined using parametric bi-cubic splined patches. This mathematical representation is then used as input to an algorithm that generates a color shaded image of the geometry. A discussion of the techniques used in the mathematical representation of the geometry and in the rendering of the color shaded display is presented. The results include examples of color shaded displays, which are contrasted with wire frame type displays. The examples also show the use of mapped surface pressures in terms of color shaded images of V/STOL fighter/attack aircraft and advanced turboprop aircraft.

Increased light-use efficiency sustains net primary productivity of shaded coffee plants in agroforestry system.

PubMed

Charbonnier, Fabien; Roupsard, Olivier; le Maire, Guerric; Guillemot, Joannès; Casanoves, Fernando; Lacointe, André; Vaast, Philippe; Allinne, Clémentine; Audebert, Louise; Cambou, Aurélie; Clément-Vidal, Anne; Defrenet, Elsa; Duursma, Remko A; Jarri, Laura; Jourdan, Christophe; Khac, Emmanuelle; Leandro, Patricia; Medlyn, Belinda E; Saint-André, Laurent; Thaler, Philippe; Van Den Meersche, Karel; Barquero Aguilar, Alejandra; Lehner, Peter; Dreyer, Erwin

2017-08-01

In agroforestry systems, shade trees strongly affect the physiology of the undergrown crop. However, a major paradigm is that the reduction in absorbed photosynthetically active radiation is, to a certain extent, compensated by an increase in light-use efficiency, thereby reducing the difference in net primary productivity between shaded and non-shaded plants. Due to the large spatial heterogeneity in agroforestry systems and the lack of appropriate tools, the combined effects of such variables have seldom been analysed, even though they may help understand physiological processes underlying yield dynamics. In this study, we monitored net primary productivity, during two years, on scales ranging from individual coffee plants to the entire plot. Absorbed radiation was mapped with a 3D model (MAESPA). Light-use efficiency and net assimilation rate were derived for each coffee plant individually. We found that although irradiance was reduced by 60% below crowns of shade trees, coffee light-use efficiency increased by 50%, leaving net primary productivity fairly stable across all shade levels. Variability of aboveground net primary productivity of coffee plants was caused primarily by the age of the plants and by intraspecific competition among them (drivers usually overlooked in the agroforestry literature) rather than by the presence of shade trees. © 2017 John Wiley & Sons Ltd.

Rewiring of auxin signaling under persistent shade.

PubMed

Pucciariello, Ornella; Legris, Martina; Costigliolo Rojas, Cecilia; Iglesias, María José; Hernando, Carlos Esteban; Dezar, Carlos; Vazquez, Martín; Yanovsky, Marcelo J; Finlayson, Scott A; Prat, Salomé; Casal, Jorge J

2018-05-22

Light cues from neighboring vegetation rapidly initiate plant shade-avoidance responses. Despite our detailed knowledge of the early steps of this response, the molecular events under prolonged shade are largely unclear. Here we show that persistent neighbor cues reinforce growth responses in addition to promoting auxin-responsive gene expression in Arabidopsis and soybean. However, while the elevation of auxin levels is well established as an early event, in Arabidopsis , the response to prolonged shade occurs when auxin levels have declined to the prestimulation values. Remarkably, the sustained low activity of phytochrome B under prolonged shade led to ( i ) decreased levels of PHYTOCHROME INTERACTING FACTOR 4 (PIF4) in the cotyledons (the organs that supply auxin) along with increased levels in the vascular tissues of the stem, ( ii ) elevated expression of the PIF4 targets INDOLE-3-ACETIC ACID 19 ( IAA19 ) and IAA29 , which in turn reduced the expression of the growth-repressive IAA17 regulator, ( iii ) reduced abundance of AUXIN RESPONSE FACTOR 6, ( iv ) reduced expression of MIR393 and increased abundance of its targets, the auxin receptors, and ( v ) elevated auxin signaling as indicated by molecular markers. Mathematical and genetic analyses support the physiological role of this system-level rearrangement. We propose that prolonged shade rewires the connectivity between light and auxin signaling to sustain shade avoidance without enhanced auxin levels.

Assessing the influence of skin color and tooth shade value on perceived smile attractiveness.

PubMed

Sabherwal, Ruchika S; Gonzalez, Juan; Naini, Farhad B

2009-06-01

The authors conducted a study to determine whether variations in skin color would influence perceptions of smile attractiveness for a given tooth shade value. Using a photograph of a woman smiling, the authors altered skin color to consist of four tones (fair, fair/medium, medium/dark and dark) and altered tooth shade value (brightness) to range from 00 (brightest) to 05 (darkest). Two groups of judges (70 dentists, 70 laypeople) completed a questionnaire and rated the images for smile attractiveness. For most tooth shade values (00, 01, 03, 04, 05), multiple mixed linear regression showed that variation in skin color influenced respondents' perceptions of smile attractiveness (P < .001). For images corresponding to tooth shade values 01, 02, 03, 04 and 05, men provided lower ratings than did women (P < .05). Attractiveness ratings increased with the age of participants (P < .05). Dentists rated images higher than did laypeople (P < .05). Variation in skin color for most tooth shade values influenced dentists' and laypeople's perceived smile attractiveness. Dentists and laypeople did not perceive the brightest tooth shade to be the most attractive, and they did not perceive all skin colors to be equally attractive with bright white teeth. Respondents perceived dark skin with bright white teeth and fair skin with dark teeth as relatively unattractive.

[Comparison of the color difference between teeth underwent cold light whitening and two kinds of shade guides].

PubMed

Xu, Y X

2018-06-18

To investigate which shade guide, Vitapan Classical or Vita Bleachedguide 3DMaster, is better matched with the color of teeth in judging whitening effect, by comparing the color difference between shade tabs and corresponding teeth underwent cold light tooth whitening. A total of 60 patients underwent Beyond cold light tooth whitening from May 2014 to April 2016. The patients were divided into two experimental groups according to the shade guide used. Vitapan Classical shade guide was used to judge whitening effect in one group, and Vita Bleachedguide 3DMaster shade guide was used in another. Shade matching was carried out before and after whitening in both the two groups, and the results were recorded by digital photographs. Shade matching procedures were carried out by two doctors independently. If they chose the same tab, it would be seen as the shade matching result; While if they chose different tabs, another doctor would be invited to make a decision. Photographs were taken in preset conditions: intraoral photos of the full dentition in the front, and the proportion of shooting was 1:3; aperture was F22; shutter speed was 1/200; intensity of flash was M/8; ISO value was 200. The photographs were analyzed by Photoshop software. Chromatic values were measured, and color difference values were calculated. Measuring of chromatic values was carried out by three doctors independently, and all the photos were measured twice by each doctor. Six measure results of each photo were recorded, and the maximum and the minimum were excluded, then the mean was seen as the final result. The color difference values were compared by independent-sample t test. Besides, changes of shade tabs after whitening in the two groups were recorded. Color difference value was 5.06±1.71 in Vitapan Classical group, and 3.39±1.36 in Vita Bleachedguide 3D-Master group. There was statistically significant difference between the two groups (t=4.68,P<0.001). Change of shade tabs was 3.63±1.75 in Vitapan Classical group, and 2.23±1.01 in Vita Bleachedguide 3DMaster group. Vita Bleachedguide 3D-Master is better matched with the color of teeth, so it is preferred in judging the effect of cold light tooth whitening.

Quantifying Discretization Effects on Brain Trauma Simulations

DTIC Science & Technology

2016-01-01

arbitrarily formed meshes can propagate error when resolving interactions among the skull , cerebrospinal fluid, and brain. We compared Lagrangian, pure...embedded methods from top to bottom. ......3 Fig. 2 Loading node-set for Eulerian rotational problem. The dark shaded area around the skull is the area to...and top inner edges of the skull . The example shown is a Lagrangian rotational model. The red and green materials represent the brain and skull

Materials for Adaptive Structural Acoustic Control. Volume 1

DTIC Science & Technology

1993-04-06

FOLLOWING PAGE 14. SUBJECT TERMS 15. NUMBER OF PAGES 16. PRICE CODE 17. SECURITY CLASSIFICATION 18. SECURITY CLASSIFICATION 19. SECURITY CLASSIFICATION 20...375 Rubber is a highly nonlinear clastic medium. In the unstressed compliant state, the molecules ate coiled and tangled . but under stress the molecules...one-dimensional system, \\\\here tangle (solid dots) and the oblique (open circle) states are the shaded area represents the level of thermal energy

Compositional changes in 'Bartlett' pear ( Pyrus communis L.) cell wall polysaccharides as affected by sunlight conditions.

PubMed

Raffo, María D; Ponce, Nora M A; Sozzi, Gabriel O; Vicente, Ariel R; Stortz, Carlos A

2011-11-23

Preharvest conditions can have a great impact on fruit quality attributes and postharvest responses. Firmness is an important quality attribute in pear, and excessive softening increases susceptibility to bruising and decay, thus limiting fruit postharvest life. Textural characteristics of fruits are determined at least in part by cell wall structure and disassembly. Few studies have analyzed the influence of fruit preharvest environment in softening, cell wall composition, and degradation. In the current work 'Bartlett' pears grown either facing the sun (S) or in the shade (H) were harvested and stored for 13 days at 20 °C. An evaluation of fruit soluble solids, acidity, color, starch degradation, firmness, cell wall yield, pectin and matrix glycan solubilization, depolymerization, and monosaccharide composition was carried out. Sun-exposed pears showed more advanced color development and similar levels of starch degradation, sugars, and acids than shaded fruit. Sunlight-grown pears were at harvest firmer than shade-grown pears. Both fruit groups softened during storage at 20 °C, but even after ripening, sun-exposed pears remained firmer. Sunlight exposure did not have a great impact on pectin molecular weight. Instead, at harvest a higher proportion of water-solubilized uronic acids and alkali-solubilized neutral sugars and a larger mean molecular size of tightly bound glycans was found in sun-exposed pears. During ripening cell wall catabolism took place in both sun- and shade-grown pears, but pectin solubilization was clearly delayed in sun-exposed fruit. This was associated with decreased removal of RG I-arabinan side chains rather than with reduced depolymerization.

Tradeoffs between income, biodiversity, and ecosystem functioning during tropical rainforest conversion and agroforestry intensification

PubMed Central

Steffan-Dewenter, Ingolf; Kessler, Michael; Barkmann, Jan; Bos, Merijn M.; Buchori, Damayanti; Erasmi, Stefan; Faust, Heiko; Gerold, Gerhard; Glenk, Klaus; Gradstein, S. Robbert; Guhardja, Edi; Harteveld, Marieke; Hertel, Dietrich; Höhn, Patrick; Kappas, Martin; Köhler, Stefan; Leuschner, Christoph; Maertens, Miet; Marggraf, Rainer; Migge-Kleian, Sonja; Mogea, Johanis; Pitopang, Ramadhaniel; Schaefer, Matthias; Schwarze, Stefan; Sporn, Simone G.; Steingrebe, Andrea; Tjitrosoedirdjo, Sri S.; Tjitrosoemito, Soekisman; Twele, André; Weber, Robert; Woltmann, Lars; Zeller, Manfred; Tscharntke, Teja

2007-01-01

Losses of biodiversity and ecosystem functioning due to rainforest destruction and agricultural intensification are prime concerns for science and society alike. Potentially, ecosystems show nonlinear responses to land-use intensification that would open management options with limited ecological losses but satisfying economic gains. However, multidisciplinary studies to quantify ecological losses and socioeconomic tradeoffs under different management options are rare. Here, we evaluate opposing land use strategies in cacao agroforestry in Sulawesi, Indonesia, by using data on species richness of nine plant and animal taxa, six related ecosystem functions, and on socioeconomic drivers of agroforestry expansion. Expansion of cacao cultivation by 230% in the last two decades was triggered not only by economic market mechanisms, but also by rarely considered cultural factors. Transformation from near-primary forest to agroforestry had little effect on overall species richness, but reduced plant biomass and carbon storage by ≈75% and species richness of forest-using species by ≈60%. In contrast, increased land use intensity in cacao agroforestry, coupled with a reduction in shade tree cover from 80% to 40%, caused only minor quantitative changes in biodiversity and maintained high levels of ecosystem functioning while doubling farmers' net income. However, unshaded systems further increased income by ≈40%, implying that current economic incentives and cultural preferences for new intensification practices put shaded systems at risk. We conclude that low-shade agroforestry provides the best available compromise between economic forces and ecological needs. Certification schemes for shade-grown crops may provide a market-based mechanism to slow down current intensification trends. PMID:17360392

Tradeoffs between income, biodiversity, and ecosystem functioning during tropical rainforest conversion and agroforestry intensification.

PubMed

Steffan-Dewenter, Ingolf; Kessler, Michael; Barkmann, Jan; Bos, Merijn M; Buchori, Damayanti; Erasmi, Stefan; Faust, Heiko; Gerold, Gerhard; Glenk, Klaus; Gradstein, S Robbert; Guhardja, Edi; Harteveld, Marieke; Hertel, Dietrich; Höhn, Patrick; Kappas, Martin; Köhler, Stefan; Leuschner, Christoph; Maertens, Miet; Marggraf, Rainer; Migge-Kleian, Sonja; Mogea, Johanis; Pitopang, Ramadhaniel; Schaefer, Matthias; Schwarze, Stefan; Sporn, Simone G; Steingrebe, Andrea; Tjitrosoedirdjo, Sri S; Tjitrosoemito, Soekisman; Twele, André; Weber, Robert; Woltmann, Lars; Zeller, Manfred; Tscharntke, Teja

2007-03-20

Losses of biodiversity and ecosystem functioning due to rainforest destruction and agricultural intensification are prime concerns for science and society alike. Potentially, ecosystems show nonlinear responses to land-use intensification that would open management options with limited ecological losses but satisfying economic gains. However, multidisciplinary studies to quantify ecological losses and socioeconomic tradeoffs under different management options are rare. Here, we evaluate opposing land use strategies in cacao agroforestry in Sulawesi, Indonesia, by using data on species richness of nine plant and animal taxa, six related ecosystem functions, and on socioeconomic drivers of agroforestry expansion. Expansion of cacao cultivation by 230% in the last two decades was triggered not only by economic market mechanisms, but also by rarely considered cultural factors. Transformation from near-primary forest to agroforestry had little effect on overall species richness, but reduced plant biomass and carbon storage by approximately 75% and species richness of forest-using species by approximately 60%. In contrast, increased land use intensity in cacao agroforestry, coupled with a reduction in shade tree cover from 80% to 40%, caused only minor quantitative changes in biodiversity and maintained high levels of ecosystem functioning while doubling farmers' net income. However, unshaded systems further increased income by approximately 40%, implying that current economic incentives and cultural preferences for new intensification practices put shaded systems at risk. We conclude that low-shade agroforestry provides the best available compromise between economic forces and ecological needs. Certification schemes for shade-grown crops may provide a market-based mechanism to slow down current intensification trends.

A conflict-based model of color categorical perception: evidence from a priming study.

PubMed

Hu, Zhonghua; Hanley, J Richard; Zhang, Ruiling; Liu, Qiang; Roberson, Debi

2014-10-01

Categorical perception (CP) of color manifests as faster or more accurate discrimination of two shades of color that straddle a category boundary (e.g., one blue and one green) than of two shades from within the same category (e.g., two different shades of green), even when the differences between the pairs of colors are equated according to some objective metric. The results of two experiments provide new evidence for a conflict-based account of this effect, in which CP is caused by competition between visual and verbal/categorical codes on within-category trials. According to this view, conflict arises because the verbal code indicates that the two colors are the same, whereas the visual code indicates that they are different. In Experiment 1, two shades from the same color category were discriminated significantly faster when the previous trial also comprised a pair of within-category colors than when the previous trial comprised a pair from two different color categories. Under the former circumstances, the CP effect disappeared. According to the conflict-based model, response conflict between visual and categorical codes during discrimination of within-category pairs produced an adjustment of cognitive control that reduced the weight given to the categorical code relative to the visual code on the subsequent trial. Consequently, responses on within-category trials were facilitated, and CP effects were reduced. The effectiveness of this conflict-based account was evaluated in comparison with an alternative view that CP reflects temporary warping of perceptual space at the boundaries between color categories.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takahashi, Ryo, E-mail: inter.takahashi@gmail.com; Todo, Yasuyuki, E-mail: yastodo@k.u-tokyo.ac.jp

In recent years, shade coffee certification programs have attracted increasing attention from forest conservation and development organizations. The certification programs could be expected to promote forest conservation by providing a premium price to shade coffee producers. However, little is known about the significance of the conservation efforts generated by certification programs. In particular, the relationship between the impact of the certification and producer characteristics has yet to be examined. The purpose of this study, which was conducted in Ethiopia, was to examine the impact of a shade coffee certification program on forest conservation and its relationship with the socioeconomic characteristicsmore » of the producers. Remote sensing data of 2005 and 2010 was used to gauge the changes in forest area. Employing a probit model, we found that a forest coffee area being certified increased the probability of forest conservation by 19.3 percentage points relative to forest coffee areas lacking certification. We also found that although economically poor producers tended to engage in forest clearing, the forest coffee certification program had a significant impact on these producers. This result suggests that the certification program significantly affects the behaviors of economically poor producers and motivates these producers to conserve the forest. -- Highlights: • We employed the probit mode to evaluate the impact of the shade coffee certification on forest conservation in Ethiopia. • We estimated how the impact of the certification varied among producers with different characteristics. • The certification increased the probability of conserving forest by 19.3 percentage points. • Certification program motivated the economically poor producers to conserve the forest.« less

Evaluation of polymerization-dependent changes in color and translucency of resin composites using two formulae.

PubMed

Paravina, Rade D; Kimura, Mikio; Powers, John M

2005-09-01

The aim of this study was to evaluate polymerization-dependent changes in the color and translucency parameter (TP) of resin composites and to compare results obtained using two color-difference metric formulae, CIELAB and CIEDE 2000. Twenty-eight shades of commercial resin composites were analyzed. Specimens (n = 5) were made as discs, 11 mm in diameter and 2-mm thick, using cylindrical molds. Data were collected before and after composite polymerization, using a spectrophotometer. In regard to in vitro color changes of composites (DeltaE*) a DeltaE76 of 3.7 or greater was considered to be an unacceptable color change. Data were analyzed by analysis of variance, and Fisher's protected least significant difference (PLSD) intervals for comparison of means were calculated at the 0.05 level of significance. Mean polymerization-dependent differences in color were DeltaE00 = 4.48 (2.11) and DeltaE76 = 5.51 (2.68). The DeltaTP00 range was 2.57, while the DeltaTP76 range was 2.89. Mean polymerization-dependent differences in translucency were DeltaTP00 = 0.84 (0.77) and DeltaTP76 = 0.87 (0.76). Analysis of variance showed significant differences among composites, shades, and their interactions (P < 0.0001; power = 1.0). Regression equations and r values for the two color-difference formulae and all evaluated TP values showed very strong correlation. In conclusion, within the limitations of this study, polymerization-dependent changes in color and translucency were highly varied. The majority of shades showed polymerization-dependent differences in color higher than the DeltaE76 = 3.7. The TP generally increased after light polymerization by light activation. The very strong correlation (r > 0.97) between the two color-difference formulae indicates that the limitations of the CIELAB system do not appear to be a problem when evaluating composites; however, recorded differences between DeltaE76 and DeltaE00 values stress the importance of data conversion.

Crassulacean acid metabolism in the shade. Studies on an epiphytic fern, Pyrrosia longifolia, and other rainforest species from Australia.

PubMed

Winter, K; Osmond, C B; Hubick, K T

1986-01-01

Crassulacean acid metabolism (CAM) was studied in a tropical epiphytic fern, Pyrrosia longifolia, from a fully sun-exposed and from a very shaded site in Northern Queensland, Australia. Measurements of instantaneous net CO 2 exchange showed carbon gain via CO 2 dark fixation with some net CO 2 uptake also occuring during late afternoon, in both sun and shade fronds. Maximum rates of net CO 2 uptake and the nocturnal increase in titratable acidity were lower in shade than in sun fronds. δ 13 C values of sun and shade fronds were not significantly different, and ranged between-14 and-15‰ suggesting that, in the long term, carbon gain was mainly via CO 2 dark fixation. Sun fronds had a higher light compensation point of photosynthesis than shade fronds but the same quantum yield. Yet there was no acclimation of photosynthetic O 2 evolution, (measured at 5% CO 2 ) in sun and shade fronds and photosynthesis saturated at between 200 and 400 μmol quanta m -2 s -1 . Use of higher light intensities for photosynthesis of sun fronds was probably precluded by low nutrient availability. Total nitrogen was less than 1% of dry weight in fully expanded sun and shade fronds. Exposure of shade fronds to full sunlight for 6 h led to a 60% decline in the quantum yield of photosynthesis and to a decline in variable fluorescence measured at room temperature. Photoinhibition by high light was also observed in Hoya nicholsoniae, a rainforest climber growing in deep shade. This species also exhibited CAM as demonstrated by nocturnal net CO 2 uptake, nocturnal acidification and a δ 13 C value of-14‰. Photosynthetic O 2 evolution in this species was saturated at 2.5% of full sunlight. Two species of Dendrobium (Orchidaceae) from sun-exposed sites, one species exhibiting CAM and the other one exhibiting net CO 2 uptake exclusively during daytime via conventional C 3 photosynthesis, showed similar light response curves and the same quantum yield for photosynthetic O 2 evolution.

RIPARIAN SHADE CONTROLS ON STREAM TEMPERATURE NOW AND IN THE FUTURE ACROSS TRIBUTARIES OF THE COLUMBIA RIVER, USA

EPA Science Inventory

Future climates may warm stream temperatures altering aquatic communities and threatening socioeconomically-important species. These impacts will vary across large spatial extents and require special evaluation tools. Statistical stream network models (SSNs) account for spatial a...

Characterization of cocoa production, income diversification and shade tree management along a climate gradient in Ghana.

PubMed

Abdulai, Issaka; Jassogne, Laurence; Graefe, Sophie; Asare, Richard; Van Asten, Piet; Läderach, Peter; Vaast, Philippe

2018-01-01

Reduced climatic suitability due to climate change in cocoa growing regions of Ghana is expected in the coming decades. This threatens farmers' livelihood and the cocoa sector. Climate change adaptation requires an improved understanding of existing cocoa production systems and farmers' coping strategies. This study characterized current cocoa production, income diversification and shade tree management along a climate gradient within the cocoa belt of Ghana. The objectives were to 1) compare existing production and income diversification between dry, mid and wet climatic regions, and 2) identify shade trees in cocoa agroforestry systems and their distribution along the climatic gradient. Our results showed that current mean cocoa yield level of 288kg ha-1yr-1 in the dry region was significantly lower than in the mid and wet regions with mean yields of 712 and 849 kg ha-1 yr-1, respectively. In the dry region, farmers diversified their income sources with non-cocoa crops and off-farm activities while farmers at the mid and wet regions mainly depended on cocoa (over 80% of annual income). Two shade systems classified as medium and low shade cocoa agroforestry systems were identified across the studied regions. The medium shade system was more abundant in the dry region and associated to adaptation to marginal climatic conditions. The low shade system showed significantly higher yield in the wet region but no difference was observed between the mid and dry regions. This study highlights the need for optimum shade level recommendation to be climatic region specific.

Characterization of cocoa production, income diversification and shade tree management along a climate gradient in Ghana

PubMed Central

Jassogne, Laurence; Graefe, Sophie; Asare, Richard; Van Asten, Piet; Läderach, Peter; Vaast, Philippe

2018-01-01

Reduced climatic suitability due to climate change in cocoa growing regions of Ghana is expected in the coming decades. This threatens farmers’ livelihood and the cocoa sector. Climate change adaptation requires an improved understanding of existing cocoa production systems and farmers’ coping strategies. This study characterized current cocoa production, income diversification and shade tree management along a climate gradient within the cocoa belt of Ghana. The objectives were to 1) compare existing production and income diversification between dry, mid and wet climatic regions, and 2) identify shade trees in cocoa agroforestry systems and their distribution along the climatic gradient. Our results showed that current mean cocoa yield level of 288kg ha-1yr-1 in the dry region was significantly lower than in the mid and wet regions with mean yields of 712 and 849 kg ha-1 yr-1, respectively. In the dry region, farmers diversified their income sources with non-cocoa crops and off-farm activities while farmers at the mid and wet regions mainly depended on cocoa (over 80% of annual income). Two shade systems classified as medium and low shade cocoa agroforestry systems were identified across the studied regions. The medium shade system was more abundant in the dry region and associated to adaptation to marginal climatic conditions. The low shade system showed significantly higher yield in the wet region but no difference was observed between the mid and dry regions. This study highlights the need for optimum shade level recommendation to be climatic region specific. PMID:29659629

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

The effects of mechanical stress and spectral shading on the growth and allocation of ten genotypes of a stoloniferous plant.

PubMed

Liu, Yun; Schieving, Feike; Stuefer, Josef F; Anten, Niels P R

2007-01-01

Because plants protect each other from wind, stand density affects both the light climate and the amount of mechanical stress experienced by plants. But the potential interactive effects of mechanical stress and canopy shading on plant growth have rarely been investigated and never in stoloniferous plants which, due to their creeping growth form, can be expected to respond differently to these factors than erect plants. Plants of ten genotypes of the stoloniferous species Potentilla reptans were subjected to two levels of mechanical stress (0 or 40 daily flexures) and two levels of spectral shading (15 % of daylight with a red:far red ratio of 0.3 vs. 50 % daylight and a red:far red ratio of 1.2). Mechanically stressed plants produced more leaves with shorter more flexible petioles, more roots, and more but less massive stolons. Responses to spectral shading were mostly in the opposite direction to thigmomorphogenesis, including the production of thinner, taller petioles made of more rigid tissue. The degree of thigmomorphogenesis was either independent of light climate or stimulated by spectral shading. At the genotypic level there were no clear correlations between responses to shade and mechanical stress. These results suggest that in stoloniferous plants mechanical stress results in clones with a more compact, shorter shoot structure and more roots. This response does not appear to be suppressed by canopy shading, which suggests that wind shielding (reduced mechanical stress) by neighbours in dense vegetation serves as a cue that induces shade avoidance responses such as increased petiole elongation.

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. 780.506 Section 780.506 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION....506 Dependence of exemption on shade-grown tobacco operations. The exemption provided by section 13(a...

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

Code of Federal Regulations, 2010 CFR

2010-07-01

... Employment or Agricultural Employees in Processing Shade-Grown Tobacco; Exemption From Minimum Wage and... 29 Labor 3 2010-07-01 2010-07-01 false Definition of âshade-grown tobacco.â 780.505 Section 780.505 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR...

Douglas-fir in northern California: effects of shade on germination, survival, and growth

Treesearch

Rudolph O. Strothmann

1972-01-01

Effects of four light intensities on germination, survival, and early growth of Douglas-fir (Pseudotsuga menziesii) were studied on south-facing cutblocks in northwestern California. Tested were four shade intensities: 0, 25, 50, and 75 percent. On seeded spots, 50 percent shade resulted in greatest germination and survival, being significantly...

Involvement of abscisic acid in correlative control of flower abscission in soybean

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yarrow, G.L.

1985-01-01

Studies were carried out in three parts: (1) analysis of endogenous abscisic acid (ABA) in abscising and non-abscising flowers, (2) partitioning of radio-labelled ABA and photoassimilates within the soybean raceme, and (3) shading experiments, wherein endogenous levels, metabolism and partitioning of ABA were determined. Endogenous concentrations of ABA failed to show any consistent relationship to abscission of soybean flowers. Partitioning of radiolabelled ABA and photoassimilates displayed consistently higher sink strengths (% DPM) for both /sup 3/H-ABA and /sup 14/C-photoassimilates for non-abscising flowers than for abscising flowers within control racemes. Shading flowers with aluminum foil, 48 hrs prior to sampling, resultedmore » in lowered endogenous ABA concentrations at 12, 17 and 22 days after anthesis (DAA), but not at 0 or 4 DAA. No differences were found in the catabolism of /sup 3/H-ABA between shaded (abscising) and non-shaded (non-abscising) flowers. Reduced partitioning of ABA and photoassimilates to shaded flowers resulted when shades were applied at 0, 4, 12, and 17 DAA, but not at 22 DAA.« less

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

PubMed

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

2007-12-26

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

Woody plant diversity and structure of shade-grown-coffee plantations in northern Chiapas, Mexico.

PubMed

Soto-Pinto, L; Romero-Alvarado, Y; Caballero-Nieto, J; Segura Warnholtz, G

2001-01-01

Shade-grown coffee is an agricultural system that contains some forest-like characteristics. However, structure and diversity are poorly known in shade coffee systems. In 61 coffee-growers' plots of Chiapas, Mexico, structural variables of shade vegetation and coffee yields were measured, recording species and their use. Coffee stands had five vegetation strata. Seventy seven woody species mostly used as wood were found (mean density 371.4 trees per hectare). Ninety percent were native species (40% of the local flora), the remaining were introduced species, mainly fruit trees/shrubs. Diametric distribution resembles that of a secondary forest. Principal Coordinates Analysis grouped plots in four classes by the presence of Inga, however the majority of plots are diverse. There was no difference in equitability among groups or coffee yields. Coffee yield was 835 g clean coffee per shrub, or ca. 1,668 kg ha-1. There is a significant role of shade-grown coffee as diversity refuge for woody plants and presumably associated fauna as well as an opportunity for shade-coffee growers to participate in the new biodiversity-friendly-coffee market.

An application of the MPP to the interactive manipulation of stereo images of digital terrain models

NASA Technical Reports Server (NTRS)

Pol, Sanjay; Mcallister, David; Davis, Edward

1987-01-01

Massively Parallel Processor algorithms were developed for the interactive manipulation of flat shaded digital terrain models defined over grids. The emphasis is on real time manipulation of stereo images. Standard graphics transformations are applied to a 128 x 128 grid of elevations followed by shading and a perspective projection to produce the right eye image. The surface is then rendered using a simple painter's algorithm for hidden surface removal. The left eye image is produced by rotating the surface 6 degs about the viewer's y axis followed by a perspective projection and rendering of the image as described above. The left and right eye images are then presented on a graphics device using standard stereo technology. Performance evaluations and comparisons are presented.

Exterior Space Retrofitting Planning with Possible Effect on Building Thermal Characteristics

NASA Astrophysics Data System (ADS)

Berezin, D. V.

2017-11-01

The problems of mass housing which was serially designed and produced throughout Eastern European and former Soviet cities in the middle of the 20th century, in regard to its solar-related thermal conditions improvement by refurbishing are raised in the paper. The impact of functional zones’ dimensions (based on the dwellers’ domestic actions) on shading properties of balconies and loggias is analyzed. As a result, the ratios of exterior space area (as a complex of shading elements related to balconies/loggias) to the windows area that reflect the frequency of the indoor air overheating are determined which can serve as a simple evaluative thermal comfort-related tool for projected and existing buildings under a real solar activity between the geographic latitudes 55° - 56°.

Multiple Solutions for Reconfiguration to Address Partial Shading Losses in Solar Photovoltaic Arrays

NASA Astrophysics Data System (ADS)

Sharma, Nikesh; Pareek, Smita; Chaturvedi, Nitin; Dahiya, Ratna

2018-03-01

Solar photovoltaic (SPV) systems are steadily rising and considered as the best alternatives to meet the rising demand of energy. In developing countries like India, SPV’s contribution being a clean energy is the most favourable. However, experiences have shown that produced power of these systems is usually affected due to day, night, seasonal variations, insolation, partial shading conditions etc. Among these parameters, partial shading causes a huge reduction in output power of PV systems. This results in lack of confidence for this technology among users. Thus, it is important and a major challenge in PV systems to minimize the effect of partial shading on their energy production. The work in this paper aims to propose solutions for reconfiguration of solar photovoltaic arrays in order to reduce partial shading losses and thus to enhance power generation.

Impact of abutment material on peri-implant soft tissue color. An in vitro study.

PubMed

Sala, Leticia; Bascones-Martínez, Antonio; Carrillo-de-Albornoz, Ana

2017-09-01

The objectives of the present study is to determine the differences in peri-implant soft tissue color with the utilization of titanium, titanium gold-plated, white zirconia, Vita Classical (VC) A4-shaded zirconia, and fluorescent white zirconia abutments and to establish the influence of gingival thickness on the resulting color. Four implants were contralaterally inserted in 19 fresh pig mandibles, and the color of the peri-implant mucosa with the different abutments was spectrophotometrically measured at 1-, 2-, and 3-mm height from the margin. At 1-mm height, titanium significantly differed from all zirconia abutments in lightness (L*), chroma along red axis (a*), and chroma along yellow-blue axis (b*) parameters. At 2 mm, all zirconia abutments differed from titanium in b* but only fluorescent zirconia in a*. At 3 mm, titanium differed from VC A4-shaded and fluorescent zirconia abutments in b*. At soft tissue thicknesses <1 and 1-2 mm, titanium differed from fluorescent zirconia in a* and b* and from VC A4-shaded zirconia in b*; at thickness >2 mm, no differences were found among abutments. All abutments differed from natural teeth in a* and b* at all heights and thicknesses except for fluorescent zirconia at thickness >2 mm. The Euclidean distance (ΔΕ) differed between titanium abutments and gold, VC A4, and fluorescent zirconia at <1- and 1-2-mm thicknesses. The natural gingival color was not reproduced with any abutment at gingival thicknesses <2 mm. The worst color match was with titanium abutments and the best with fluorescent zirconia, followed by VC A4-shaded zirconia. At gingival thicknesses >2 mm, no differences were detected among abutments. This study demonstrates that the type of abutment and the gingival thickness affect the resulting peri-implant gingival color.

Earth Rings for Planetary Environment Control

NASA Astrophysics Data System (ADS)

Pearson, Jerome; Oldson, John; Levin, Eugene; Carroll, Joseph

2002-01-01

For most of its past, large parts of the Earth have experienced subtropical climates, with high sea levels and no polar icecaps. This warmer environment was punctuated 570, 280, and 3 million years ago with periods of glaciation that covered temperate regions with thick ice for millions of years. At the end of the current ice age, a warmer climate could flood coastal cities, even without human-caused global warming. In addition, asteroids bombard the Earth periodically, with impacts large enough to destroy most life on Earth, and the sun is warming inexorably. This paper proposes a concept to solve these problems simultaneously, by creating an artificial planetary ring about the Earth to shade it. Past proposals for space climate control have depended on gigantic engineering structures launched from Earth and placed in Earth orbit or at the Earth-Sun L1 libration point, requiring fabrication, large launch masses and expense, constant control, and repair. Our solution is to begin by using lunar material, and then mine and remove Earth-orbit-crossing asteroids and discard the tailings into Earth orbit, to form a broad, flat ring like those of Saturn. This solution is evaluated and compared with other alternatives. Such ring systems can persist for thousands of years, and can be maintained by shepherding satellites or by continual replenishment from new asteroids to replace the edges of the ring lost by diffusion. An Earth ring at R = 1.3-1.83 RE would shade only the equatorial regions, moderating climate extremes, and could reverse a century of global warming. It could also absorb particles from the radiation belts, making trips to high Earth orbit and GEO safer for humans and for electronics. It would also light the night many times as bright as the full moon. A preliminary design of the ring is developed, including its location, mass, composition, stability, and timescale required. A one-dimensional climate model is used to evaluate the Earth ring performance. Earth, lunar, and asteroidal material sources are evaluated; asteroid retrieval is addressed, along with techniques for processing and forming the ring to the proper thickness and density. The ring could consist of particles, or fabricated satellite structures. Environmental concerns and effects on existing satellites in various Earth orbits are addressed. There are uncertainties in our understanding of climate and its control. But it appears that the Earth ring could control the Earth's temperature and its latitudinal variation, make dangerous asteroids useful, reduce the intensity of the Van Allen radiation belts, provide nighttime illumination without power, and create an artificial ionosphere for radio communication.

Effect of Late Planting and Shading on Cellulose Synthesis during Cotton Fiber Secondary Wall Development

PubMed Central

Chen, Ji; Lv, Fengjuan; Liu, Jingran; Ma, Yina; Wang, Youhua; Chen, Binglin; Meng, Yali; Zhou, Zhiguo; Oosterhuis, Derrick M.

2014-01-01

Cotton-rapeseed or cotton-wheat double cropping systems are popular in the Yangtze River Valley and Yellow River Valley of China. Due to the competition of temperature and light resources during the growing season of double cropping system, cotton is generally late-germinating and late-maturing and has to suffer from the coupling of declining temperature and low light especially in the late growth stage. In this study, late planting (LP) and shading were used to fit the coupling stress, and the coupling effect on fiber cellulose synthesis was investigated. Two cotton (Gossypium hirsutum L.) cultivars were grown in the field in 2010 and 2011 at three planting dates (25 April, 25 May and 10 June) each with three shading levels (normal light, declined 20% and 40% PAR). Mean daily minimum temperature was the primary environmental factor affected by LP. The coupling of LP and shading (decreased cellulose content by 7.8%–25.5%) produced more severe impacts on cellulose synthesis than either stress alone, and the effect of LP (decreased cellulose content by 6.7%–20.9%) was greater than shading (decreased cellulose content by 0.7%–5.6%). The coupling of LP and shading hindered the flux from sucrose to cellulose by affecting the activities of related cellulose synthesis enzymes. Fiber cellulose synthase genes expression were delayed under not only LP but shading, and the coupling of LP and shading markedly postponed and even restrained its expression. The decline of sucrose-phosphate synthase activity and its peak delay may cause cellulose synthesis being more sensitive to the coupling stress during the later stage of fiber secondary wall development (38–45 days post-anthesis). The sensitive difference of cellulose synthesis between two cultivars in response to the coupling of LP and shading may be mainly determined by the sensitiveness of invertase, sucrose-phosphate synthase and cellulose synthase. PMID:25133819

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 predicted that germination mechanisms to detect canopy shade based on temperature cues are widespread in species depending on nurse plants, especially bird-dispersed species. PMID:17259226

The Photochemical Reflectance Index from Directional Cornfield Reflectances: Observations and Simulations

NASA Technical Reports Server (NTRS)

Cheng, Yen-Ben; Middleton, Elizabeth M.; Zhang, Qingyuan; Corp, Lawrence A.; Dandois, Jonathan; Kustas, William P.

2012-01-01

The two-layer Markov chain Analytical Canopy Reflectance Model (ACRM) was linked with in situ hyperspectral leaf optical properties to simulate the Photochemical Reflectance Index (PRI) for a corn crop canopy at three different growth stages. This is an extended study after a successful demonstration of PRI simulations for a cornfield previously conducted at an early vegetative growth stage. Consistent with previous in situ studies, sunlit leaves exhibited lower PRI values than shaded leaves. Since sunlit (shaded) foliage dominates the canopy in the reflectance hotspot (coldspot), the canopy PRI derived from field hyperspectral observations displayed sensitivity to both view zenith angle and relative azimuth angle at all growth stages. Consequently, sunlit and shaded canopy sectors were most differentiated when viewed along the azimuth matching the solar principal plane. These directional PRI responses associated with sunlit/shaded foliage were successfully reproduced by the ACRM. As before, the simulated PRI values from the current study were closer to in situ values when both sunlit and shaded leaves were utilized as model input data in a two-layer mode, instead of a one-layer mode with sunlit leaves only. Model performance as judged by correlation between in situ and simulated values was strongest for the mature corn crop (r = 0.87, RMSE = 0.0048), followed by the early vegetative stage (r = 0.78; RMSE = 0.0051) and the early senescent stage (r = 0.65; RMSE = 0.0104). Since the benefit of including shaded leaves in the scheme varied across different growth stages, a further analysis was conducted to investigate how variable fractions of sunlit/shaded leaves affect the canopy PRI values expected for a cornfield, with implications for 20 remote sensing monitoring options. Simulations of the sunlit to shaded canopy ratio near 50/50 +/- 10 (e.g., 60/40) matching field observations at all growth stages were examined. Our results suggest in the importance of the sunlit/shaded fraction and canopy structure in understanding and interpreting PRI.

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. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

Predicting Stream Temperature After Riparian Vegetation Removal

Treesearch

Bruce J. McGurk

1989-01-01

Removal of stream channel shading during timber harvest operations may raise the stream temperature and adversely affect desirable aquatic populations. Field work in California at one clearcut and one mature fir site demonstrated diurnal water temperature cycles and provided data to evaluate two stream temperature prediction techniques. Larger diurnal temperature...

Commentary: Learner-Based Listening and Technological Authenticity

ERIC Educational Resources Information Center

Robin, Richard

2007-01-01

Language teachers know that even the best technology cannot provide the high degree of interaction required to acquire meaningful proficiency in a foreign language. Even the most polished packages available today cannot evaluate learner input and provide subtle shades of context-based feedback, except in the narrowest of circumstances. In this…

Realtime Hourly Data Table

Science.gov Websites

Tables View the latest hourly text summary CLICK ON UNDERLINED HOUR / SHADED BOX FOR THE LATEST CYCLE 00z Dump Tables View the latest rap text summary CLICK ON UNDERLINED HOUR / SHADED BOX FOR THE LATEST CYCLE Data Dump Tables View the latest model data text summary NAM GFS GDS CLICK ON UNDERLINED HOUR / SHADED

Shade Tolerance of Festuca paradoxa Desv., a Cool-Season Grass Native to North America

Treesearch

Nadia Navarrete-Tindall; Larry Mechlin; J. W. Van Sambeek

2003-01-01

Paradox grass (Festuca paradoxa Desv.) is a native cool-season grass found in prairies and forest openings. Paradox grass has not been included in tree plantings. To determine paradox grass adaptation to shaded environmmts, we established a pot experiment in the shade laboratory at the University of Missouri Horticulture and Agroforestry Research...

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…

Avian response to shade‐layer restoration in coffee plantations in Puerto Rico

USGS Publications Warehouse

Irizarry, Amarilys D.; Collazo, Jaime A.; Pacifici, Krishna; Reich, Brian J.; Battle, Kathryn E.

2018-01-01

Documenting the evolving processes associated with habitat restoration and how long it takes to detect avian demographic responses is crucial to evaluate the success of restoration initiatives and to identify ways to improve their effectiveness. The importance of this endeavor prompted the U.S. Fish and Wildlife Service and the USDA Natural Resources Conservation Service to evaluate their sun‐to‐shade coffee restoration program in Puerto Rico initiated in 2003. We quantified the responses of 12 resident avian species using estimates of local occupancy and extinction probabilities based on surveys conducted in 2015–2017 at 65 restored farms grouped according to time‐since‐initial‐restoration (TSIR): new (2011–2014), intermediate (2007–2010), and old (2003–2006). We also surveyed 40 forest sites, which served as reference sites. Vegetation complexity increased with TSIR, ranging between 35 and 40% forest cover in farms 6–9 years TSIR. Forest specialists (e.g. Loxigilla portoricencis) exhibited highest average occupancy in farms initially classified as intermediate (6–9 years) and old (>10 years), paralleling occupancy in secondary forests. Occupancy of open‐habitat specialists (e.g. Tiaris olivaceus) was more variable, but higher in recently restored farms. Restoring the shade layer has the potential to heighten ecological services derived from forest specialists (e.g. frugivores) without losing the services of many open‐habitat specialists (e.g. insectivores). Annual local extinction probability for forest specialists decreased with increasing habitat complexity, strengthening the potential value of shade restoration as a tool to enhance habitat for avifauna that evolved in forested landscapes.

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

NASA Astrophysics Data System (ADS)

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

2012-06-01

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

Chlorophyll Fluorescence Is a Better Proxy for Sunlit Leaf Than Total Canopy Photosynthesis

NASA Astrophysics Data System (ADS)

Chen, J. M.; Wang, Z.; Zhang, F.; Mo, G.

2015-12-01

Chlorophyll fluorescence (CF) results from non-photochemical quenching during plant photosynthesis under excessive radiation. We explore the relationship between gross primary productivity (GPP) and CF using a process ecosystem model, which separates a vegetation canopy into sunlit and shaded leaf groups and simulates the total canopy GPP as the sum of sunlit and shaded leaf GPP. Using GOME-2 and GOSAT data acquired in 2010 over the global land surface, we found that measured CF signals gridded in 1 degree resolution are well correlated with simulated total GPP and its sunlit and shaded components, but the correlation coefficients (R) are largest for the sunlit GPP and smallest for shaded GPP. The seasonal R2 values vary from 0.57 to 0.74, 0.58 to 0.71, and 0.48 to 0.56 for sunlit, total and shaded GPP, respectively. The significance levels for these correlations are all greater than p<0.01. Averaged over the globe, the total simulated shaded GPP is 39% of the total GPP. Theoretically, CF from vegetation comes mostly from sunlit leaves. The significant correlation between measured canopy-level CF and the shaded GPP is likely due to the correlation between shaded and sunlit GPP as both increase with leaf area index. Our simulation confirms the validity of using canopy-level CF measurements to assess the total GPP as the first approximation, although these measurements are a consistently better indicator of sunlit GPP than total GPP. In previous studies, the R2 values for the correlation between CF and total GPP were found to range from 0.76 to 0.88, 0.56 to 0.78, and 0.57 to 0.77 for MPI-BGC, MODIS and CASA model results, respectively. These values are similar or larger than those for sunlit GPP simulated in our study, but are considerably larger than those for total GPP in our study because the correlation for total GPP is contaminated by the inclusion of shaded GPP. All these three models use canopy total light use efficiency without considering the differences between sunlit and shaded leaves, and therefore they mostly capture spatio-temporal variations in sunlit GPP. We therefore argue that solar-induced CF measured from vegetation is a better proxy of sunlit GPP than the total GPP, and the use of CF data for assessing the terrestrial carbon cycle can be improved when sunlit and shaded GPP are modelled separately.

High-Fidelity Geometric Modeling and Mesh Generation for Mechanics Characterization of Polycrystalline Materials

DTIC Science & Technology

2015-01-07

and anisotropic quadrilateral meshes, which can be used as the control mesh for high-order T- spline surface modeling. Archival publications (published...anisotropic T-meshes for the further T- spline surface construction. Finally, a gradient flow-based method is developed to improve the T-mesh quality...shade-off. Halos are bright or dark thin regions around the boundary of the sample. These false edges around the object make many segmentation

Towards Determination of Visual Requirements for Augmented Reality Displays and Virtual Environments for the Airport Tower

DTIC Science & Technology

2006-06-01

allowing substantial see-around capability. Regions of visual suppression due to binocular rivalry ( luning ) are shown along the shaded flanks of...that the visual suppression of binocular rivalry, luning , (Velger, 1998, p.56-58) associated with the partial overlap conditions did not materially...tags were displayed. Thus, the frequency of conflicting binocular contours was reduced. In any case, luning does not seem to introduce major

The linear shade guide design of Vita 3D-master performs as well as the original design of the Vita 3D-master.

PubMed

Corcodel, N; Rammelsberg, P; Jakstat, H; Moldovan, O; Schwarz, S; Hassel, A J

2010-11-01

Visual tooth colour assessment by use of the Vita 3D-Master(®) (3D; Vita Zahnfabrik, Bad Säckingen, Germany) is well documented. To improve handling, a new linear arrangement of the shade tabs has been introduced (LG; Linearguide 3D-Master(®) ). The purpose of this study was to investigate whether the linear design has an effect on shade matching. Fifty-six students underwent identical, theoretical and practical training, by use of an Internet learning module [Toothguide Training Software(®) (TT)] and a standardised training programme [Toothguide Training Box(®) (TTB)]. Each student then matched 30 randomly chosen shade tabs presented in an intra-oral setting by a standardised device [Toothguide Check Box(®) (TCB)]; 15 matches were made using the 3D and 15 using the LG shade guide system, under a daylight lamp (840 matches for each guide). It was recorded to what extent the presented and selected shade tabs, or the lightness group of the tabs, matched, also the needed time for colour matching. The results showed that 35% of perfect matches were observed for the 3D and 32% for the LG. The lightness group was correct in 59% of cases for 3D and 56% for LG. Mean time needed for matching of tabs and lightness group was no different between groups (no significant difference for any assessment). Within the limitations of the study design, the colour assessment with regard to performance and time needed in shade matching was not different with the LG or the 3D. Therefore, the user should choose which shade tab arrangement is more applicable. © 2010 Blackwell Publishing Ltd.

Phenotypic Plasticity in Reproductive Traits of the Perennial Shrub Ulex europaeus in Response to Shading: A Multi-Year Monitoring of Cultivated Clones.

PubMed

Atlan, Anne; Hornoy, Benjamin; Delerue, Florian; Gonzalez, Maya; Pierre, Jean-Sébastien; Tarayre, Michèle

2015-01-01

Phenotypic plasticity may be advantageous for plants to be able to rapidly cope with new and changing environments associated with climate change or during biological invasions. This is especially true for perennial plants, as they may need a longer period to respond genetically to selective pressures than annuals, and also because they are more likely to experience environmental changes during their lifespan. However, few studies have explored the plasticity of the reproductive life history traits of woody perennial species. This study focuses on a woody shrub, Ulex europaeus (common gorse), and on the response of its reproductive traits to one important environmental factor, shading. The study was performed on clones originating from western France (within the native range of this invasive species) and grown for seven years. We compared traits of plants grown in a shade treatment (with two successive shade levels) vs. full natural light. The traits monitored included flowering onset, pod production and seed predation. All traits studied responded to shading, exhibiting various levels of plasticity. In particular, dense shade induced a radical but reversible decrease in flower and pod production, while moderate shade had little effect on reproductive traits. The magnitude of the response to dense shade depended on the genotype, showing a genetically based polymorphism of plasticity. The level of plasticity also showed substantial variations between years, and the effect of environmental variations was cumulative over time. This suggests that plasticity can influence the lifetime fitness of U. Europaeus and is involved in the capacity of the species to grow under contrasting environmental conditions.

Phenotypic Plasticity in Reproductive Traits of the Perennial Shrub Ulex europaeus in Response to Shading: A Multi-Year Monitoring of Cultivated Clones

PubMed Central

Atlan, Anne; Hornoy, Benjamin; Delerue, Florian; Gonzalez, Maya; Pierre, Jean-Sébastien; Tarayre, Michèle

2015-01-01

Phenotypic plasticity may be advantageous for plants to be able to rapidly cope with new and changing environments associated with climate change or during biological invasions. This is especially true for perennial plants, as they may need a longer period to respond genetically to selective pressures than annuals, and also because they are more likely to experience environmental changes during their lifespan. However, few studies have explored the plasticity of the reproductive life history traits of woody perennial species. This study focuses on a woody shrub, Ulex europaeus (common gorse), and on the response of its reproductive traits to one important environmental factor, shading. The study was performed on clones originating from western France (within the native range of this invasive species) and grown for seven years. We compared traits of plants grown in a shade treatment (with two successive shade levels) vs. full natural light. The traits monitored included flowering onset, pod production and seed predation. All traits studied responded to shading, exhibiting various levels of plasticity. In particular, dense shade induced a radical but reversible decrease in flower and pod production, while moderate shade had little effect on reproductive traits. The magnitude of the response to dense shade depended on the genotype, showing a genetically based polymorphism of plasticity. The level of plasticity also showed substantial variations between years, and the effect of environmental variations was cumulative over time. This suggests that plasticity can influence the lifetime fitness of U. Europaeus and is involved in the capacity of the species to grow under contrasting environmental conditions. PMID:26383627

[Comparative analysis of some factors in tooth color matching].

PubMed

Török, Judit; Mauks, Levente; Márton, Sándor; Hegedűs, Csaba

2014-09-01

Recently (nowadays) to achieve a natural looking restoration is an ever increasing demand from the patients and also from the doctor side. To select the right color of the restoration matching the remaining natural teeth is always a challenging task. A clinical study was performed at the University of Debrecen Faculty of Dentristry with the help of dental students using two different shade guides. The study tested the influence of gender and knowledge of color science on shade matching. 78 students were asked to find the right matching color of the same upper canine to two different shade guides (Vitapan Classic and Vita 3D-Master) under standard condition. After informing the student about the basic principles of color the matching procedure was repeated. Results were analyzed statistically. In our study we found that gender does not influence the color choice. Matching accuracy is not increased by better knowledge of colors. We can conclude that significantly less students matched the proper color with Vitapan Classic shade guide after information of the property of colors without training the shade selection. Within the limitation of the study design it was concluded that not more students selected the proper color even after giving them information about colors, instructions about shade selections. For the same one canine several color were selected by the participants (6 types with Vitapan Classic and 19 types with Vita 3D-Master) which conformed that visual determination is not a reliably consistent way of the tooth shade selection. The Vita Company 1990s developed 3D-Master shade guide is not widely used, although we found the repeatability is more than 70%.

A continent-wide analysis of the shade requirements of red and western grey kangaroos

PubMed Central

Roberts, J. A.; Coulson, G.; Munn, A. J.; Kearney, M. R.

2016-01-01

ABSTRACT Foraging time may be constrained by a suite of phenomena including weather, which can restrict a species' activity and energy intake. This is recognized as pivotal for many species whose distributions are known to correlate with climate, including kangaroos, although such impacts are rarely quantified. We explore how differences in shade seeking, a thermoregulatory behavior, of 2 closely-related kangaroo species, Macropus rufus (red kangaroos) and M. fuliginosus (western grey kangaroos), might reflect differences in their distributions across Australia. We observed foraging and shade-seeking behavior in the field and, together with local weather observations, calculated threshold radiant temperatures (based on solar and infrared radiant heat loads) over which the kangaroos retreated to shade. We apply these calculated tolerance thresholds to hourly microclimatic estimates derived from daily-gridded weather data to predict activity constraints across the Australian continent over a 10-year period. M. fuliginosus spent more time than M. rufus in the shade (7.6 ± 0.7 h versus 6.4 ± 0.9 h) and more time foraging (11.8 ± 0.5 h vs. 10.0 ± 0.6 h), although total time resting was equivalent (∼8.2 h). M. rufus tolerated 19°C higher radiant temperatures than M. fuliginosus (89°C versus 70°C radiant temperature). Across Australia, we predicted M. fuliginosus to be more restricted to shade than M. rufus, with higher absolute shade requirements farther north. These results corroborate previous findings that M. rufus is more adept at dealing with heat than M. fuliginosus and indicate that M. rufus is less dependent on shade on a continental scale. PMID:27857963

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

PubMed

Ishii, Hiroaki; Hamada, Yoko; Utsugi, Hajime

2012-10-01

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

Evaluation of Discoloration Removal by Polishing Resin Composites Submitted to Staining in Different Drink Solutions

PubMed Central

Spina, Denis Roberto Falcão; Grossi, João Ricardo Almeida; Cunali, Rafael Schlögel; Baratto Filho, Flares; da Cunha, Leonardo Fernandes; Gonzaga, Carla Castiglia; Correr, Gisele Maria

2015-01-01

The aim of this study was to evaluate the discoloration effects of water, cola-based soft drink, coffee, and wine on resin composites used in restorative dentistry and the possibility of removing the stain with chair side manual polishing. The A2 shade of three materials was tested. Disc specimens were prepared. A spectrophotometer was used to measure the baseline CIE-Lab color parameters of each material (n=10) 24 hours after sample preparation. Samples were then immersed in a cola-based soft drink, coffee, or wine for 1 hour every day, for 30 days. For the remaining hours, the specimens were stored in distilled water. In the control group, the specimens were immersed in water for the whole period. The color differences (ΔE) were calculated after 7 and 30 days of storage, and after polishing with coarse Sof-Lex discs, and analyzed by two-way ANOVA with repeated measures and Tukey's HSD test (α=0.05). Luna presented higher ΔE values (3.41)a followed by Durafill (2.82)b and Herculite (2.24)c. For the drink solutions, ΔE values were higher for wine (4.40)a followed by coffee (2.59)b and for cola-based soft drink (2.23)c and water (2.13)c which were statistically similar. For time, ΔE values were higher for 30 days (3.97)a and then for 7 days (2.48)b and after polishing (2.04)c. The results indicate that color stability is material dependent. The types of drinks that patients consume also influence the color stability of restorative materials. PMID:27347551

[The fabrication and chroma study of a kind of custom shade guide with metal substrate].

PubMed

Chen, Ling; Liu, Xian; Xu, Li-qiang; Chao, Yong-lie; Liu, Wen-fang; Chen, Xiao-fang

2007-06-01

This study was to explore the chroma of a custom shade guide with metal substrate. A custom shade guide sample was fabricated using the central maxillary incisor as a model,which was corresponding to the colour of VITAPAN shade guide.The colour of each shade tab was measured with PR-650 spectrophotometer when every porcelain was added. From the opaque to glaze, the lightness was decreased and the chroma was increased distinctively; When the body porcelain were baked over their corresponding opaque, the lightness was decreased and the chroma was increased; When the enamel porcelain and the translucent porcelain were added on, the lightness and chroma were decreased slightly; the glaze could increase the lightness. The "add on" porcelain can affect the final color of the restoration, and the effects of each porcelain layer were different from each other.

Differences between the human eye and the spectrophotometer in the shade matching of tooth colour.

PubMed

Gómez-Polo, Cristina; Gómez-Polo, Miguel; Celemin-Viñuela, Alicia; Martínez Vázquez De Parga, Juan Antonio

2014-06-01

The aim of this work was to assess the agreement between instrumental and visual colour matching. Shade selection with the 3DMaster Toothguide (Vita-Zahnfabrik) was performed for 1361 maxillary central incisors and compared with the shade obtained with the EasyShade Compact (Vita-Zahnfabrik) spectrophotometer. We observed a greater correlation between the objective method and the subjective one in the colour dimension of lightness (Kappa 0.6587), followed by hue (Kappa 0.4337) and finally chroma (Kappa 0.3578). The colour dimension in which the greatest agreement is seen between the operator and the spectrophotometer is value or lightness. This study reveals differences between the measurement of colour via spectrophotometry and the visual shade selection method. According to our results, there is better agreement in the value or lightness colour dimension, which is the most important one in the choice of tooth colour. Copyright © 2014 Elsevier Ltd. All rights reserved.

Competition among surface roots in a selectively-logged, semi-deciduous forest in southeastern Mexico - effects on seedlings of two species of contrasting shade tolerance

Treesearch

Matthew Dickinson; D.F. Wigham

2013-01-01

Experimental manipulations of root competition on naturally established seedlings were conducted across canopy openness and soil depth gradients in a selectively-logged, semideciduous forest on limestone-derived soils in southeastern Mexico. We studied the relatively shade intolerant mahogany (Swietenia macrophylla, Meliaceae) and shade tolerant...

Importance of Shading to Visitors Selecting a Campsite at Indian Boundary Campground in Tennessee

Treesearch

George A. James; Harold K. Cordell

1970-01-01

Campers at Indian Boundary Campground in Tenr.essee were interviewed during 1966 and 1967 to determine the amount of shading they preferred. The overstory in this campground was selectively thinned several years earlier. This gave campers a choice of campsites, ranging from those so heavily shaded that little sunlight reached the forest floor to...

Response of naturally regenerated and underplanted white oak (Quercus alba L.) seedlings 6 years following midstory removal

Treesearch

Jared M. Craig; John M. Lhotka; Jeffrey W. Stringer

2013-01-01

Historically, the abundance of red maple and shade-tolerant understory species was limited by fire and other disturbances. In the absence of periodic disturbance, regeneration of oaks with intermediate shade tolerance has been hindered due to inadequate light conditions created by shade-tolerant midstory trees. Research suggests that midstory removal in oak-dominated...

Habitat use by the endangered Karner blue butterfly in oak woodlands: The influence of canopy cover

USGS Publications Warehouse

Grundel, Ralph; Pavlovic, Noel B.; Sulzman, Christina L.

1998-01-01

The Karner blue butterfly Lycaeides melissa samuelis is an endangered species residing in the Great Lakes and northeastern regions of the United States. Increased canopy cover is a major factor implicated in the decline of the Karner blue at many locales. Therefore, we examined how the butterfly's behavior varied with canopy cover. Adult males at Indiana Dunes National Lakeshore used habitat under canopy openings for nearly 90% of their activities; females used openings and shaded areas more equally. The frequency of oviposition on the sole host plant, wild lupine Lupinus perennis, was highest under 30–60% canopy cover even though lupine was more abundant in more open areas. Larvae fed preferentially on larger lupine plants and on lupines in denser patches. However, lupines were generally larger in the shade. Therefore, shade-related trade-offs existed between lupine abundance and distribution of larval feeding and oviposition. Also, heterogeneity of shading by sub-canopy woody vegetation was greater at oviposition sites than at sites where lupine did not grow. Given the importance of shade heterogeneity, a mixture of canopy openings and shade, on a scale similar to daily adult movement range, should be beneficial for this butterfly.

Hydraulic acclimation to shading in boreal conifers of varying shade tolerance.

PubMed

Schoonmaker, Amanda L; Hacke, Uwe G; Landhäusser, Simon M; Lieffers, Victor J; Tyree, Melvin T

2010-03-01

The purpose of this study was to determine how shading affects the hydraulic and wood-anatomical characteristics of four boreal conifers (Pinus banksiana, Pinus contorta, Picea glauca and Picea mariana) that differ in shade tolerance. Plants were grown in an open field and under a deciduous-dominated overstory for 6 years. Sapwood- and leaf-area specific conductivity, vulnerability curves, and anatomical measurements (light and scanning electron microscopy) were made on leading shoots from six to nine trees of each treatment combination. There was no difference in sapwood-area specific conductivity between open-grown and understory conifers, although two of four species had larger tracheid diameters in the open. Shaded conifers appeared to compensate for small diameter tracheids by changes in pit membrane structure. Scanning electron microscopy revealed that understory conifers had thinner margo strands, greater maximum pore size in the margo, and more torus extensions. All of these trends may contribute to inadequate sealing of the torus. This is supported by the fact that all species showed increased vulnerability to cavitation when grown in the understory. Although evaporative demand in an understory environment is low, a rapid change into fully exposed conditions could be detrimental for shaded conifers.

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 Central

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

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.

LED and Halogen Light Transmission through a CAD/CAM Lithium Disilicate Glass-Ceramic.

PubMed

Pereira, Carolina Nemesio de Barros; De Magalhães, Cláudia Silami; Daleprane, Bruno; Peixoto, Rogéli Tibúrcio Ribeiro da Cunha; Ferreira, Raquel da Conceição; Cury, Luiz Alberto; Moreira, Allyson Nogueira

2015-01-01

The effect of thickness, shade and translucency of CAD/CAM lithium disilicate glass-ceramic on light transmission of light-emitting diode (LED) and quartz-tungsten-halogen units (QTH) were evaluated. Ceramic IPS e.max CAD shades A1, A2, A3, A3.5, high (HT) and low (LT) translucency were cut (1, 2, 3, 4 and 5 mm). Light sources emission spectra were determined. Light intensity incident and transmitted through each ceramic sample was measured to determine light transmission percentage (TP). Statistical analysis used a linear regression model. There was significant interaction between light source and ceramic translucency (p=0.008) and strong negative correlation (R=-0.845, p<0.001) between ceramic thickness and TP. Increasing one unit in thickness led to 3.17 reduction in TP. There was no significant difference in TP (p=0.124) between shades A1 (ß1=0) and A2 (ß1=-0.45) but significant reduction occurred for A3 (ß1=-0.83) and A3.5 (ß1=-2.18). The interaction QTH/HT provided higher TP (ß1=0) than LED/HT (ß1=-2.92), QTH/LT (ß1=-3.75) and LED/LT (ß1=-5.58). Light transmission was more effective using halogen source and high-translucency ceramics, decreased as the ceramic thickness increased and was higher for the lighter shades, A1 and A2. From the regression model (R2=0.85), an equation was obtained to estimate TP value using each variable ß1 found. A maximum TP of 25% for QTH and 20% for LED was found, suggesting that ceramic light attenuation could compromise light cured and dual cure resin cements polymerization.

Randomized controlled clinical trial on bleaching sensitivity and whitening efficacy of hydrogen peroxide versus combinations of hydrogen peroxide and ozone.

PubMed

Al-Omiri, Mahmoud K; Al Nazeh, Abdullah A; Kielbassa, Andrej M; Lynch, Edward

2018-02-05

The clinical efficacy regarding bleaching sensitivity and tooth shade lightening using a standard hydrogen peroxide (H 2 O 2 ) bleaching gel was compared with the additional use of ozone either before or after application of H 2 O 2 . Using computer-generated tables, 45 participants were randomly allocated into three groups (n = 15 each) in this investigator-driven, single-centre trial. In Group 1, upper anterior teeth were bleached using ozone (produced via a healOzone X4 device) for 60 seconds, then 38% H 2 O 2 for 20 minutes; in Group 2, 38% H 2 O 2 application (20 min) was followed by ozone (60 s); air produced by the healOzone machine (60 s) followed by 38% H 2 O 2 (20 min) was used in Group 3 (control). Bleaching sensitivity was evaluated via visual analogue scales, and a treatment-blinded reader objectively recorded tooth shades using a colorimeter before and 24 hours after bleaching (at α = 0.05). The H 2 O 2 /ozone combination did not result in pain sensations, while both ozone/H 2 O 2 and H 2 O 2 alone increased bleaching sensitivity (p < 0.001). Teeth achieved lighter shades (higher L*/lower b* values) after bleaching in all groups (p < 0.001), while Ozone boosted lighter tooth shades, irrespective of its use before or after H 2 O 2 (p < 0.05). Due to the complimentary effects, applying ozone after H 2 O 2 seems preferable for bleaching.

Optical properties of pre-colored dental monolithic zirconia ceramics.

PubMed

Kim, Hee-Kyung; Kim, Sung-Hun

2016-12-01

The purposes of this study were to evaluate the optical properties of recently marketed pre-colored monolithic zirconia ceramics and to compare with those of veneered zirconia and lithium disilicate glass ceramics. Various shades of pre-colored monolithic zirconia, veneered zirconia, and lithium disilicate glass ceramic specimens were tested (17.0×17.0×1.5mm, n=5). CIELab color coordinates were obtained against white, black, and grey backgrounds with a spectrophotometer. Color differences of the specimen pairs were calculated by using the CIEDE2000 (ΔE 00 ) formula. The translucency parameter (TP) was derived from ΔE 00 of the specimen against a white and a black background. X-ray diffraction was used to determine the crystalline phases of monolithic zirconia specimens. Data were analyzed with 1-way ANOVA, Scheffé post hoc, and Pearson correlation testing (α=0.05). For different shades of the same ceramic brand, there were significant differences in L * , a * , b * , and TP values in most ceramic brands. With the same nominal shade (A2), statistically significant differences were observed in L * , a * , b * , and TP values among different ceramic brands and systems (P<0.001). The color differences between pre-colored monolithic zirconia and veneered zirconia or lithium disilicate glass ceramics of the corresponding nominal shades ranged beyond the acceptability threshold. Due to the high L * values and low a * and b * values, pre-colored monolithic zirconia ceramics can be used with additional staining to match neighboring restorations or natural teeth. Due to their high value and low chroma, unacceptable color mismatch with adjacent ceramic restorations might be expected. Copyright © 2016 Elsevier Ltd. All rights reserved.

Distinctive effects of allochthonous and autochthonous organic matter on CDOM spectra in a tropical lake

NASA Astrophysics Data System (ADS)

Pena Mello Brandão, Luciana; Silva Brighenti, Ludmila; Staehr, Peter Anton; Asmala, Eero; Massicotte, Philippe; Tonetta, Denise; Antônio Rodrigues Barbosa, Francisco; Pujoni, Diego; Fernandes Bezerra-Neto, José

2018-05-01

Despite the increasing understanding about differences in carbon cycling between temperate and tropical freshwater systems, our knowledge on the importance of organic matter (OM) pools on light absorption properties in tropical lakes is very scarce. We performed a factorial mesocosm experiment in a tropical lake (Minas Gerais, Brazil) to evaluate the effects of increased concentrations of allochthonous and autochthonous OM, and differences in light availability on the light absorption characteristics of chromophoric dissolved organic matter (CDOM). Autochthonous OM deriving from phytoplankton ( ˜ Chl a) was stimulated by addition of nutrients, while OM from degradation of terrestrial leaves increased allochthonous OM, and neutral shading was used to manipulate light availability. Effects of the additions and shading on DOC, Chl a, nutrients, total suspended solid concentrations (TSM) and spectral CDOM absorption were monitored every 3 days. CDOM quality was characterized by spectral indices (S250-450, S275-295, S350-450, SR and SUVA254). Effects of carbon sources and shading on the spectral CDOM absorption was investigated through principal component (PCA) and redundancy (RDA) analyses. The two different OM sources affected CDOM quality very differently and shading had minor effects on OM levels, but significant effects on OM quality, especially in combination with nutrient additions. Spectral indices (S250-450 and SR) were mostly affected by allochthonous OM addition. The PCA showed that enrichment by allochthonous carbon had a strong effect on the CDOM spectra in the range between 300 and 400 nm, while the increase in autochthonous carbon increased absorption at wavelengths below 350 nm. Our study shows that small inputs of allochthonous OM can have large effects on the spectral light absorption compared to large production of autochthonous OM, with important implications for carbon cycling in tropical lakes.

Mixed-conifer forests of central Oregon: effects of logging and fire exclusion vary with environment.

PubMed

Merschel, Andrew G; Spies, Thomas A; Heyerdahl, Emily K

Twentieth-century land management has altered the structure and composition of mixed-conifer forests and decreased their resilience to fire, drought, and insects in many parts of the Interior West. These forests occur across a wide range of environmental settings and historical disturbance regimes, so their response to land management is likely to vary across landscapes and among ecoregions. However, this variation has not been well characterized and hampers the development of appropriate management and restoration plans. We identified mixed-conifer types in central Oregon based on historical structure and composition, and successional trajectories following recent changes in land use, and evaluated how these types were distributed across environmental gradients. We used field data from 171 sites sampled across a range of environmental settings in two subregions: the eastern Cascades and the Ochoco Mountains. We identified four forest types in the eastern Cascades and four analogous types with lower densities in the Ochoco Mountains. All types historically contained ponderosa pine, but differed in the historical and modern proportions of shade-tolerant vs. shade-intolerant tree species. The Persistent Ponderosa Pine and Recent Douglas-fir types occupied relatively hot–dry environments compared to Recent Grand Fir and Persistent Shade Tolerant sites, which occupied warm–moist and cold–wet environments, respectively. Twentieth-century selective harvesting halved the density of large trees, with some variation among forest types. In contrast, the density of small trees doubled or tripled early in the 20th century, probably due to land-use change and a relatively cool, wet climate. Contrary to the common perception that dry ponderosa pine forests are the most highly departed from historical conditions, we found a greater departure in the modern composition of small trees in warm–moist environments than in either hot–dry or cold–wet environments. Furthermore, shade-tolerant trees began infilling earlier in cold–wet than in hot–dry environments and also in topographically shaded sites in the Ochoco Mountains. Our new classification could be used to prioritize management that seeks to restore structure and composition or create resilience in mixed-conifer forests of the region.

Detecting the Benefits of Shade Management in the Thermal Regime of an Upland River Under Positive and Negative Phases of the NAO

NASA Astrophysics Data System (ADS)

Wilby, R.; Johnson, M. F.

2017-12-01

Water temperature is an important determinant of river ecosystem function and health. Hence, there is growing concern about rising surface water temperatures as a consequence of global warming and human modifications to river regimes. Some agencies are advocating riparian shade management as a means of `keeping rivers cool'. As appealing as this policy might seem, there are a host of practical considerations such as which species to plant, where to plant, and how much to plant? Moreover, there can be unintended consequences for groundwater recharge, flood risk and nutrient fluxes through the buffer zone. The thermal benefits of tree-planting may also be hard to detect amidst the integrated, downstream effects of landscape shade and flows from springs. Yet, to truly evaluate shade management as an adaptation to climate change, clear evidence is needed of the costs and benefits of this local intervention. What has this got to do with natural modes of climate variability? Continental scale, hydrological impacts of ENSO, the PDO and NAO have been widely reported - these periodic variations in ocean-atmosphere circulations are often blamed for floods, droughts, wildfire, crop failures, and the like. But there is emerging evidence that such phenomena also drive inter-annual variations in the heat flux of rivers. This matters because the underlying signal can confound field and model experiments intended to test adaptation options. Here, we present evidence of NAO signatures in the water temperature regime of the River Dove, UK. We compare the amplitude of these thermal variations with the expected benefit of tree planting. We demonstrate that the difference in maximum summer water temperature between strongly positive and strongly negative NAO phases can be about 2.5°C. This is equivalent to the thermal benefit of more than 2 km of riparian shade for the river studied. So, whilst modes of climate variability undoubtedly have a global footprint, let us not forget that river management literally begins at the grass-root level.

Phase 1 of the First Solar Small Power System Experiment (experimental System No. 1). Volume 3: Appendix E - N

NASA Technical Reports Server (NTRS)

Clark, T. B. (Editor)

1979-01-01

The design of a solar electric power plant for a small community is reported. Topics covered include: (1) control configurations and interface requirements for the baseline power system; (2) annual small power system output; (3) energy requirements for operation of the collectors and control building; (4) life cycle costs and reliability predictions; (5) thermal conductivities and costs of receiver insulation materials; (6) transient thermal modelling for the baseline receiver/thermal transport system under normal and inclement operating conditions; (7) high temperature use of sodium; (8) shading in a field of parabolic collectors; and (9) buffer storage materials.

Shade changing effectiveness of plasdone and blue covarine-based whitening toothpaste on teeth stained with chlorhexidine and black tea.

PubMed

Bergesch, Vania; Baggio Aguiar, Flávio Henrique; Turssi, Cecilia Pedroso; Gomes França, Fabiana Mantovani; Basting, Roberta Tarkany; Botelho Amaral, Flávia Lucisano

2017-01-01

This study evaluated the effectiveness of toothbrushing with whitening toothpaste in altering the shade of stained human enamel. Thirty fragments of human enamel, stained with chlorhexidine/black tea underwent 1000 and 5000 brushing cycles (BC) with ( n = 10): PLS (Gel Dental Day, Bitufo), Close Up White Now, Unilever (COVB) and regular (Gel Dental Night, Bitufo) toothpaste. Images were taken before staining (baseline), after staining (STN) and following 1000 and 5000 BC and were analyzed using the CIELAB parameters (ΔE, Δb and ΔL). Data were submitted to two-way ANOVA (α = 0.05). ΔE was higher from STN to baseline; 1000 BC to STN and 5000 BC to STN ( P < 0.001). Significant differences in Δb values were found from 1000 BC to STN and 5000 BC to STN. For COVB, greater ΔL was observed from 1000 BC to STN, what differed statistically from the regular toothpaste ( P < 0.05). There was no difference between toothpaste when ΔL was calculated from 5000 CB to STN. Toothpaste containing COVB or PLS in association with 5000 BCs showed similar effectiveness in changing enamel shade; but after the first 1000 toothbrushing cycles, the use of COVB toothpaste promoted higher lightness in stained enamel.

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

Treesearch

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

2018-01-01

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

Salinity stress constrains photosynthesis in Fraxinus ornus more when growing in partial shading than in full sunlight: consequences for the antioxidant defence system

PubMed Central

Fini, Alessio; Guidi, Lucia; Giordano, Cristiana; Baratto, Maria Camilla; Ferrini, Francesco; Brunetti, Cecilia; Calamai, Luca; Tattini, Massimiliano

2014-01-01

Background and Aims A major challenge in plant ecophysiology is understanding the effects of multiple sub-optimal environmental conditions on plant performance. In most Mediterranean areas soil salinity builds up during the summer because of low availability of soil water coupled with hot temperatures. Although sunlight and soil salinity may strongly interact in determining a plant's performance, this has received relatively little attention. Methods Two-year-old seedlings of Fraxinus ornus were grown outdoors in pots during a Mediterranean summer in either 45 % (shaded plants) or 100 % (sun plants) sunlight irradiance and were supplied with either deionized water or deionized water plus 75 mm NaCl. Morpho-anatomical traits, water and ionic relations, gas exchange and photosystem II performance, concentrations of individual carotenoids, activity of antioxidant enzymes, concentrations of ascorbic acid and individual polyphenols were measured in leaves. Leaf oxidative stress and damage were estimated by in vivo analysis of stable free radicals and ultrastructural analyses. Key Results Leaf concentrations of potentially toxic ions did not markedly differ in shaded or sun plants in response to salinity. Leaves of sun plants displayed superior water use efficiency compared with leaves of shaded plants, irrespective of salinity treatment, and had both better stomatal control and higher CO2 carboxylation efficiency than leaves of shaded plants. In the salt-treated groups, the adverse effects of excess midday irradiance were greater in shade than in sun plants. The activity of enzymes responsible for detoxifying hydrogen peroxide decreased in shaded plants and increased in sun plants as a result of salinity stress. In contrast, the activity of guaiacol peroxidase and the concentration of phenylpropanoids increased steeply in response to salinity in shaded plants but were unaffected in sun plants. Conclusions It is concluded that salinity may constrain the performance of plants growing under partial shading more severely than that of plants growing under full sun during summer. The results suggest co-ordination within the antioxidant defence network aimed at detoxifying salt-induced generation of reactive oxygen species. PMID:25006177

The acclimation of Tilia cordata stomatal opening in response to light, and stomatal anatomy to vegetational shade and its components.

PubMed

Aasamaa, Krõõt; Aphalo, Pedro José

2017-02-01

Stomatal anatomical traits and rapid responses to several components of visible light were measured in Tilia cordata Mill. seedlings grown in an open, fully sunlit field (C-set), or under different kinds of shade. The main questions were: (i) stomatal responses to which visible light spectrum regions are modified by growth-environment shade and (ii) which separate component of vegetational shade is most effective in eliciting the acclimation effects of the full vegetational shade. We found that stomatal opening in response to red or green light did not differ between the plants grown in the different environments. Stomatal response to blue light was increased (in comparison with that of C-set) in the leaves grown in full vegetational shade (IABW-set), in attenuated UVAB irradiance (AB-set) or in decreased light intensity (neutral shade) plus attenuated UVAB irradiance (IAB-set). In all sets, the addition of green light-two or four times stronger-into induction light barely changed the rate of the blue-light-stimulated stomatal opening. In the AB-set, stomatal response to blue light equalled the strong IABW-set response. In attenuated UVB-grown leaves, stomatal response fell midway between IABW- and C-set results. Blue light response by neutral shade-grown leaves did not differ from that of the C-set, and the response by the IAB-set did not differ from that of the AB-set. Stomatal size was not modified by growth environments. Stomatal density and index were remarkably decreased only in the IABW- and IAB-sets. It was concluded that differences in white light responses between T. cordata leaves grown in different light environments are caused only by their different blue light response. Differences in stomatal sensitivity are not dependent on altered stomatal anatomy. Attenuated UVAB irradiance is the most efficient component of vegetational shade in stimulating acclimation of stomata, whereas decreased light intensity plays a minor role. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

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

EPA Science Inventory

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

STUDY OF CHARACTERISTICS CONTRIBUTING TO THE EFFECTIVENESS OF VISUAL DEMONSTRATIONS.

ERIC Educational Resources Information Center

BOGUSLAVSKY, GEORGE W.

SLIDES OF SELECTED TEXTBOOK ILLUSTRATIONS, DRAWN TO HIGHLIGHT THE PERTINENT AREAS OF THE ILLUSTRATION BY MEANS OF SHADING AND ILLUMINATION, WERE USED TO EVALUATE THEIR EFFECTIVENESS OVER SELECTED SLIDES OF CONVENTIONAL ILLUSTRATIONS AND DIAGRAMS IN WHICH ALL DETAILS WERE PROMINENTLY DISPLAYED. WHEN THE CONTROL SLIDES WERE PRESENTED, A TEACHER USED…

Component analysis and synthesis of dark circles under the eyes using a spectral image

NASA Astrophysics Data System (ADS)

Akaho, Rina; Hirose, Misa; Ojima, Nobutoshi; Igarashi, Takanori; Tsumura, Norimichi

2017-02-01

This paper proposes to apply nonlinear estimation of chromophore concentrations: melanin, oxy-hemoglobin, deoxyhemoglobin and shading to the real hyperspectral image of skin. Skin reflectance is captured in the wavelengths between 400nm and 700nm by hyperspectral scanner. Five-band wavelengths data are selected from skin reflectance. By using the cubic function which obtained by Monte Carlo simulation of light transport in multi-layered tissue, chromophore concentrations and shading are determined by minimize residual sum of squares of reflectance. When dark circles are appeared under the eyes, the subject looks tired and older. Therefore, woman apply cosmetic cares to remove dark circles. It is not clear about the relationship between color and chromophores distribution in the dark circles. Here, we applied the separation method of the skin four components to hyperspectral image of dark circle, and the separated components are modulated and synthesized. The synthesized images are evaluated to know which components are contributed into the appearance of dark circles. Result of the evaluation shows that the cause of dark circles for the one subject was mainly melanin pigmentation.

Radiant heat loss, an unexploited path for heat stress reduction in shaded cattle.

PubMed

Berman, A; Horovitz, T

2012-06-01

Reducing thermal radiation on shaded animals reduces heat stress independently of other means of stress relief. Radiant heat exchange was estimated as a function of climate, shade structure, and animal density. Body surface portion exposed to radiant sources in shaded environments was determined by geometrical relations to determine angles of view of radiation sources (roof underside, sky, sun-exposed ground, shaded ground) on the animal's surface. The relative representation of environment radiation sources on the body surface was determined. Animal thermal radiation balance was derived from radiant heat gained from radiation sources (including surrounding animals) and that lost from the animal surface. The animal environment was assumed to have different shade dimensions and temperatures. These were summed to the radiant heat balance of the cow. The data formed served to estimate the effect of changes in intensity of radiation sources, roof and shaded surface dimensions, and animal density on radiant heat balance (Rbal) of cattle. Roof height effect was expressed by effect of roof temperature on Rbal. Roof underside temperature (35 to 75°C) effect on Rbal was reduced by roof height. If roof height were 4m, an increase in its underside temperature from 35 to 75°C would increase mean Rbal from -63 to -2 W·m⁻², whereas if roof height were 10 m, Rbal would only increase from -99 to -88 W·m⁻². A hot ground temperature increase from 35 to 65°C reduced mean Rbal heat loss from -45 to 3 W·m⁻². Increasing the surface of the shaded area had only a minor effect on Rbal and on the effect of hot ground on Rbal. Increasing shade roof height reduced the effect of roof temperature on Rbal to minor levels when height was > 8m. Increasing the roof height from 4 to 10 m decreased Rbal from -32 to -94 W·m⁻². Increasing indirect radiation from 100 to 500 W·m⁻² was associated with an increase in Rbal from -135 to +23 W·m⁻². Their combined effects were lower Rbal with increasing roof height and a reduction in rate of decrease with increasing level of indirect radiation. Roof height as an Rbal attenuator declined with increasing indirect radiation level. The latter factor might be reduced by lowering roof surface radiation absorption and through roof heat transfer, as well as by use of shade structure elements to reduce indirect radiation in the shaded area. Radiant heat from the cow body surface may be reduced by lower cow density. Radiant heat attenuation may thus further elevate animal productivity in warm climates, with no associated operation costs. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Considerations Regarding the Optical Properties of the Composite Resin Restorative Materials

PubMed Central

Manolea, H.; Râcă, R.; Coleş, Evantia; Preotu, Gabriela; Mărăşescu, P.

2011-01-01

The purpose of this study has been to investigate the effects of certain substances frequently used in alimentation on the color stability of the composite resin restorative materials. The research hypothesis was that color stability of the composite resin is affected by the type of composite material used and by the polishing procedure. 14 samples of 5X15X2mm have been prepared from seven universal light curing restorative composite resins. The materials have manipulated and cured using LA 500 Blue Light lamp. A first color determination was done before the introduction of the samples in the dyeing agent with the help of an Easy Shade device. The samples have been splited into two lots each with seven samples. The samples from the first lot have been sectioned into three equal segments. The samples from the second lot have also been sectioned into three equal segments, and in addition to the previous group, their exterior surfaces were processed with a diamond burr. For each type of composite we have introduced a sample in one of the three chosen dyes: red alimentary colorant, coffee and red wine. The color of the samples has been determined again using the Vita Easy Shade device. From clinical point of view the results of this study shows that there are three important factors that matter when we talk about durable aesthetic results: the type of composite resin used for the restoration, the finishing and polishing procedures and the pacients’ alimentation habits. The composite resins with a good representation of the anorganic structure are easier to be polished, therefore they have only slight color modifications. Using plastic matrixes for shaping the exterior surface of the restoration is the best solution for obtaining a very smooth surface. The most significant color modifications have been done by the red wine. Coffee and to a smaller extent the red alimentary colorant have modified the color of the restoration material in a smaller degree. PMID:24778835

Negative Density Dependence Regulates Two Tree Species at Later Life Stage in a Temperate Forest

PubMed Central

Piao, Tiefeng; Chun, Jung Hwa; Yang, Hee Moon; Cheon, Kwangil

2014-01-01

Numerous studies have demonstrated that tree survival is influenced by negative density dependence (NDD) and differences among species in shade tolerance could enhance coexistence via resource partitioning, but it is still unclear how NDD affects tree species with different shade-tolerance guilds at later life stages. In this study, we analyzed the spatial patterns for trees with dbh (diameter at breast height) ≥2 cm using the pair-correlation g(r) function to test for NDD in a temperate forest in South Korea after removing the effects of habitat heterogeneity. The analyses were implemented for the most abundant shade-tolerant (Chamaecyparis obtusa) and shade-intolerant (Quercus serrata) species. We found NDD existed for both species at later life stages. We also found Quercus serrata experienced greater NDD compared with Chamaecyparis obtusa. This study indicates that NDD regulates the two abundant tree species at later life stages and it is important to consider variation in species' shade tolerance in NDD study. PMID:25058660

Sexist Attitudes Among Emerging Adult Women Readers of Fifty Shades Fiction.

PubMed

Altenburger, Lauren E; Carotta, Christin L; Bonomi, Amy E; Snyder, Anastasia

2017-02-01

Stereotypical sexist representations of men and women in popular culture reinforce rigid views of masculinity (e.g., males as being strong, in control, masterful, and aggressive) and femininity (e.g., women as being fragile and weak, unassertive, peaceful, irrational, and driven by emotions). The present study examined associations between the fictional series Fifty Shades-one popular culture mechanism that includes pervasive traditional gender role representations-and underlying sexist beliefs among a sample of 715 women ages 18-24 years. Analyses revealed associations between Fifty Shades readership and sexism, as measured through the Ambivalent Sexism Inventory. Namely women who reported reading Fifty Shades had higher levels of ambivalent, benevolent, and hostile sexism. Further, those who interpreted Fifty Shades as "romantic" had higher levels of ambivalent and benevolent sexism. Our findings support prior empirical studies noting associations between interacting with aspects of popular culture, such as television and video games, and individual beliefs and behaviors.

Is shade for horses a comfort resource or a minimum requirement?

PubMed

Holcomb, K E

2017-09-01

Shade or shelter as protection from extremes of weather is required for horses at agricultural research and teaching facilities and is recommended or required by many states, professional organizations, and industry groups. The focus of this paper is the recent research on the responses of horses to hot, sunny weather, which has begun to provide scientific evidence that characterizes how and when shade is used and any benefits shade confers on horses. These behavioral and physiological findings support provision of shade as a resource for thermal comfort and the expression of normal behavior that should be included as a standard of best care practices for healthy adult horses living in the environmental conditions reviewed, rather than an absolute minimum care requirement. Additional research is required for horses living under other environmental conditions, for very young or old horses, horses in very poor body condition, or those with compromised health to determine if their responses to hot, sunny weather differ from those presented here.

Chronic light reduction reduces overall resilience to additional shading stress in the seagrass Halophila ovalis.

PubMed

Yaakub, Siti M; Chen, Eugene; Bouma, Tjeerd J; Erftemeijer, Paul L A; Todd, Peter A

2014-06-30

Seagrasses have substantial capacity to survive long periods of light reduction, but how acclimation to chronic low light environments may influence their ability to cope with additional stress is poorly understood. This study examines the effect of temporal light reduction by adding two levels of shading to Halophila ovalis plants in two meadows with different light histories, one characterized by a low light (turbid) environment and the other by a relatively high light (clear) environment. Additional shading resulted in complete mortality for both shading treatments at the turbid site while the clear site showed a pattern of decreased shoot density and increased photochemical efficiency (Fv/Fm) with increased shading. These contrasting results for the same species in two different locations indicate that acclimation to chronic low light regimes can affect seagrass resilience and highlights the importance of light history in determining the outcome of exposure to further (short-term) stress. Copyright © 2013 Elsevier Ltd. All rights reserved.

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. © 2013 Society for Conservation Biology.

Changes in the Shadow: The Shifting Role of Shaded Leaves in Global Carbon and Water Cycles Under Climate Change

NASA Astrophysics Data System (ADS)

He, Liming; Chen, Jing M.; Gonsamo, Alemu; Luo, Xiangzhong; Wang, Rong; Liu, Yang; Liu, Ronggao

2018-05-01

Globally shaded leaves contribute to more than a half of the total increase in gross primary production (GPP; 7.6 Pg C) for 1982-2016. During 1982-2016, the fraction of shaded GPP increases by 1.1% (p < 0.01) in tropical forests and decreases by 1.4% (p < 0.01) and 1.8% (p < 0.01) in evergreen needleleaf and deciduous needleleaf boreal forests, respectively, suggesting an ecological niche of certain canopy structure for ecosystems to achieve maximum GPP. Unlike transpiration from sunlit leaves that has a turning point in the trend in 2003, global transpiration from shaded leaves steadily increased at the rate of 34 km3/year (p < 0.0001) during 1982-2016. Our study therefore suggests that shaded leaves have an increasing role in buffering the adverse impact of climate change and extremes. Further studies are still needed to reduce the uncertainties in reported trends arisen from climate forcing data, leaf area index, and land cover and land change products.

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

Photosynthesis and Biomass Allocation in Oak Seedlings Grown Under Shade

Treesearch

Shi-Jean S. Sung; Paul P. Kormanik; Stanley J. Zarnoch

1998-01-01

Abstract-Northern red oak (Quercus rubra L.) (NRO) and white oak (Q. alba L.) (WO) acorns were sown into wooden plots and grown under 30 percent shade screen (30 percent S) or 70 percent shade screen (70 percent S). Seedlings grown under full sun were the controls (C). At the end of the first year, the 30 percent S NRO had 30 percent greater seedling dry weight (DW...

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. © 2016 The American Society of Photobiology.

Molecular Profiles of Contrasting Shade Response Strategies in Wild Plants: Differential Control of Immunity and Shoot Elongation.

PubMed

Gommers, Charlotte M M; Keuskamp, Diederik H; Buti, Sara; van Veen, Hans; Koevoets, Iko T; Reinen, Emilie; Voesenek, Laurentius A C J; Pierik, Ronald

2017-02-01

Plants growing at high densities elongate their shoots to reach for light, a response known as the shade avoidance syndrome (SAS). Phytochrome-mediated detection of far-red light reflection from neighboring plants activates growth-promoting molecular pathways leading to SAS However, it is unknown how plants that complete their life cycle in the forest understory and are shade tolerant prevent SAS when exposed to shade. Here, we show how two wild Geranium species from different native light environments regulate contrasting responses to light quality cues. A comparative RNA sequencing approach unveiled the molecular underpinnings of their contrasting growth responses to far-red light enrichment. It also identified differential phytochrome control of plant immunity genes and confirmed that far-red enrichment indeed contrastingly affects resistance against Botrytis cinerea between the two species. Furthermore, we identify a number of candidate regulators of differential shade avoidance. Three of these, the receptor-like kinases FERONIA and THESEUS1 and the non-DNA binding bHLH protein KIDARI, are functionally validated in Arabidopsis thaliana through gene knockout and/or overexpression studies. We propose that these components may be associated with either showing or not showing shade avoidance responses. © 2017 American Society of Plant Biologists. All rights reserved.

Allocation strategies of savanna and forest tree seedlings in response to fire and shading: outcomes of a field experiment

NASA Astrophysics Data System (ADS)

Gignoux, Jacques; Konaté, Souleymane; Lahoreau, Gaëlle; Le Roux, Xavier; Simioni, Guillaume

2016-12-01

The forest-savanna ecotone may be very sharp in fire-prone areas. Fire and competition for light play key roles in its maintenance, as forest and savanna tree seedlings are quickly excluded from the other ecosystem. We hypothesized a tradeoff between seedling traits linked to fire resistance and to competition for light to explain these exclusions. We compared growth- and survival-related traits of two savanna and two forest species in response to shading and fire in a field experiment. To interpret the results, we decomposed our broad hypothesis into elementary tradeoffs linked to three constraints, biomass allocation, plant architecture, and shade tolerance, that characterize both savanna and adjacent forest ecosystems. All seedlings reached similar biomasses, but forest seedlings grew taller. Savanna seedlings better survived fire after topkill and required ten times less biomass than forest seedlings to survive. Finally, only savanna seedlings responded to shading. Although results were consistent with the classification of our species as mostly adapted to shade tolerance, competition for light in the open, and fire tolerance, they raised new questions: how could savanna seedlings survive better with a 10-times lower biomass than forest seedlings? Is their shade intolerance sufficient to exclude them from forest understory?

Communicating risk information: the influence of graphical display format on quantitative information perception-Accuracy, comprehension and preferences.

PubMed

Price, Melanie; Cameron, Rachel; Butow, Phyllis

2007-12-01

Statistical health risk information has proved notoriously confusing and difficult to understand. While past research indicates that presenting risk information in a frequency format is superior to relative risk and probability formats, the optimal characteristics of frequency formats are still unclear. The aim of this study is to determine the features of 1000 person frequency diagrams (pictographs) which result in the greatest speed and accuracy of graphical perception. Participants estimated the difference in chance of survival when taking or not taking Drug A, on a pictograph format, varying by mode (one-graph/two-graph), direction (vertical/horizontal), and shading (shaded/unshaded), and their preferences for the different formats. Their understanding of different components of the 1000 person diagram was assessed. Responses were timed and scored for accuracy. Horizontal pictographs were perceived faster and more accurately than vertical formats. Two-graph pictographs were perceived faster than one-graph formats. Shading reduced response time in two-graph formats, but increased response times in one-graph formats. Shaded and one-graph pictographs were preferred. As shading and one-graph formats were preferred, further clarification as to why shading negatively impacts on response times in the one-graph format is warranted. Horizontal pictographs are optimal.

The role of heterotrophic carbon acquisition by the hemiparasitic plant Rhinanthus alectorolophus in seedling establishment in natural communities: a physiological perspective.

PubMed

Těšitel, Jakub; Lepš, Jan; Vráblová, Martina; Cameron, Duncan D

2011-10-01

• Heterotrophic acquisition of substantial amounts of organic carbon by hemiparasitic plants was clearly demonstrated by numerous studies. Many hemiparasites are, however, also limited by competition for light preventing the establishment of their populations on highly productive sites. • In a growth-chamber experiment, we investigated the effects of competition for light, simulated by shading, on growth and heterotrophic carbon acquisition by the hemiparasite Rhinanthus alectorolophus attached to C(3) and C(4) hosts using analyses of biomass production and stable isotopes of carbon. • Shading had a detrimental effect on biomass production and vertical growth of the hemiparasites shaded from when they were seedlings, while shading imposed later caused only a moderate decrease of biomass production and had no effect on the height. Moreover, shading increased the proportion of host-derived carbon in hemiparasite biomass (up to 50% in shaded seedlings). • These results demonstrate that host-derived carbon can play a crucial role in carbon budget of hemiparasites, especially if they grow in a productive environment with intense competition for light. The heterotrophic carbon acquisition can allow hemiparasite establishment in communities of moderate productivity, helping well-attached hemiparasites to escape from the critical seedling stage. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

Reducing shade avoidance responses in a cereal crop

PubMed Central

Wille, Wibke; Pipper, Christian B; Rosenqvist, Eva; Andersen, Sven B

2017-01-01

Abstract Several researchers have hypothesized that shade avoidance behaviour is favoured by natural selection because it increases the fitness of individuals. Shade avoidance can be disadvantageous for crops, however, because it reduces allocation of resources to reproductive yield, increases the risk of lodging and reduces weed suppression. One approach to develop varieties with reduced shade avoidance and enhanced agronomic performance is by inducing mutations followed by phenotypic screening. We treated spring wheat seeds with ethyl methanesulfonate and screened the seedlings repeatedly under green filters for plants showing reduced elongation of the first leaf sheath and second leaf lamina. The shade avoidance responses of five promising mutant lines were further compared to non-mutated plants in a climate chamber experiment with added far-red light. Two of the selected lines displayed significantly reduced elongation under all light treatments while two lines showed reduced elongation only in added far-red light. The most promising mutant line did not differ in height from the non-mutated cultivar in neutral light, but elongated 20.6% less in strong far-red light. This traditional forward approach of screening mutagenized spring wheat produced plants with reduced shade avoidance responses. These mutants may generate new molecular handles to modify the reaction of plants to changes in light spectral distribution in traditional and novel cultivation systems. PMID:29071064

Control algorithms for dynamic windows for residential buildings

DOE PAGES

Firlag, Szymon; Yazdanian, Mehrangiz; Curcija, Charlie; ...

2015-09-30

This study analyzes the influence of control algorithms for dynamic windows on energy consumption, number of hours of retracted shades during daylight and shade operations. Five different control algorithms - heating/cooling, simple rules, perfect citizen, heat flow and predictive weather were developed and compared. The performance of a typical residential building was modeled with EnergyPlus. The program Widow was used to generate a Bi-Directional Distribution Function (BSDF) for two window configurations. The BSDF was exported to EnergyPlus using the IDF file format. The EMS feature in EnergyPlus was used to develop custom control algorithms. The calculations were made for fourmore » locations with diverse climate. The results showed that: (a) use of automated shading with proposed control algorithms can reduce the site energy in the range of 11.6-13.0%; in regard to source (primary) energy in the range of 20.1-21.6%, (b) the differences between algorithms in regard to energy savings are not high, (c) the differences between algorithms in regard to number of hours of retracted shades are visible, (e) the control algorithms have a strong influence on shade operation and oscillation of shade can occur, (d) additional energy consumption caused by motor, sensors and a small microprocessor in the analyzed case is very small.« less

Perceived color shift of ceramics according to the change of illuminating light with spectroradiometer

PubMed Central

Cha, Hyun-Suk; Yu, Bin

2013-01-01

PURPOSE Perceived color of ceramics changes by the spectral power distribution of ambient light. This study aimed to quantify the amount of shifts in color and color coordinates of clinically simulated seven all-ceramics due to the switch of three ambient light sources using a human vision simulating spectroradiometer. MATERIALS AND METHODS CIE color coordinates, such as L*, a* and b*,of ceramic specimens were measured under three light sources, which simulate the CIE standard illuminant D65 (daylight), A (incandescent lamp), and F9 (fluorescent lamp). Shifts in color and color coordinate by the switch of lights were determined. Influence of the switched light (D65 to A, or D65 to F9), shade of veneer ceramics (A2 or A3), and brand of ceramics on the shifts was analyzed by a three-way ANOVA. RESULTS Shifts in color and color coordinates were influenced by three factors (P<.05). Color shifts by the switch to A were in the range of 5.9 to 7.7 ΔE*abunits, and those by the switch to F9 were 7.7 to 10.2; all of which were unacceptable (ΔE*ab > 5.5). When switched to A, CIE a* increased (Δa*: 5.6 to 7.6), however, CIE b* increased (Δb*: 4.9 to 7.8) when switched to F9. CONCLUSION Clinically simulated ceramics demonstrated clinically unacceptable color shifts according to the switches in ambient lights based on spectroradiometric readings. Therefore, shade matching and compatibility evaluation should be performed considering ambient lighting conditions and should be done under most relevant lighting condition. PMID:24049567

Functional traits and plasticity in response to light in seedlings of four Iberian forest tree species.

PubMed

Sánchez-Gómez, David; Valladares, Fernando; Zavala, Miguel A

2006-11-01

We investigated the differential roles of physiological and morphological features on seedling survivorship along an experimental irradiance gradient in four dominant species of cool temperate-Mediterranean forests (Quercus robur L., Quercus pyrenaica Willd., Pinus sylvestris L. and Pinus pinaster Ait.). The lowest photochemical efficiency (F(v)/F(m) in dark-adapted leaves) was reached in deep shade (1% of full sunlight) in all species except Q. robur, which had the lowest photochemical efficiency in both deep shade and 100% of full sunlight. Species differed significantly in their survival in 1% of full sunlight but exhibited similar survivorship in 6, 20 and 100% of full sunlight. Shade-tolerant oaks had lower leaf area ratios, shoot to root ratios, foliage allocation ratios and higher rates of allocation to structural biomass (stem plus thick roots) than shade-intolerant pines. Overall phenotypic plasticity for each species, estimated as the difference between the minimum and the maximum mean values of the ecophysiological variables studied at the various irradiances divided by the maximum mean value of those variables, was inversely correlated with shade tolerance. Observed morphology, allocation and plasticity conformed to a conservative resource-use strategy, although observed differences in specific leaf area, which was higher in shade-tolerant species, supported a carbon gain maximization strategy. Lack of a congruent suite of traits underlying shade tolerance in the studied species provides evidence of adaptation to multiple selective forces. Although the study was based on only four species, the importance of ecophysiological variables as determinants of interspecific differences in survival in limiting light was demonstrated.

Environmental sun protection and supportive policies and practices: an audit of outdoor recreational settings in NSW coastal towns.

PubMed

Potente, Sofia; Anderson, Caroline; Karim, Muhsin

2011-08-01

The results of a sun protection audit of outdoor recreational environments in three NSW coastal towns. Thirty public swimming pools, beaches, sports grounds and skate parks were visited at two time points before and after summer (October 2009 and April 2010) and audited for the availability of sun protection, supportive polices and signage. There was insufficient shade in more than half (58%) of the observed sites at sports grounds, 49% of areas at beaches and 40% of areas at skate parks with most of these sites relying on natural shade (47-58%). Although pools were more likely to have shade available over most of the observed areas (36%) and permanent shade structures (75%), no shade was observed over any main outdoor pools. Similarly, there was only shade available over one of the main sporting grounds, one main beach and none of the main skate ramps. For other types of sun protection, sunscreen was the most popular product available either for free (nine sites) or for sale (eight sites). All pools had at least one supportive sun protection policy but only two of the total 30 sites had any related signage. This study demonstrates recent findings in relation to the accessibility of sun protection in these settings and the need for health promoting organisations to support and engage councils to invest in more sun protection strategies. The areas of focus should be shade provision particularly at beaches, skate parks and sports grounds; extending the availability of other types of sun protection; and introducing related policies and signage in more sites.

Ecological filtering by a dominant herb selects for shade tolerance in the tree seedling community of coastal dune forest.

PubMed

Tsvuura, Zivanai; Griffiths, Megan E; Gunton, Richard M; Franks, Peter J; Lawes, Michael J

2010-12-01

The regeneration niche is commonly partitioned along a gradient from shade-tolerant to shade-intolerant species to explain plant community assembly in forests. We examined the shade tolerance of tree seedlings in a subtropical coastal forest to determine whether the ecological filtering effect of a dominant, synchronously monocarpic herb (Isoglossa woodii) selects for species at either end of the light response continuum during the herb's vegetative and reproductive phases. Photosynthetic characteristics of seedlings of 20 common tree species and the herb were measured. Seedlings were grown in the greenhouse at 12-14% irradiance, and their light compensation points measured using an open-flow gas exchange system. The light compensation points for the tree species were low, falling within a narrow range from 2.1 ± 0.8 μmol m(-2) s(-1) in Celtis africana to 6.4 ± 0.7 μmol m(-2) s(-1) in Allophylus natalensis, indicating general shade tolerance, consistent with a high and narrow range of apparent quantum yield among species (0.078 ± 0.002 mol CO(2) mol(-1) photon). Rates of dark respiration were significantly lower in a generalist pioneer species (Acacia karroo) than in a forest pioneer (C. africana), or in late successional phase forest species. We argue that the general shade tolerance, and phenotypic clustering of shade tolerance, in many tree species from several families in this system, is a result of ecological filtering by the prevailing low light levels beneath the I. woodii understorey, which excludes most light-demanding species from the seedling community.

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

2016-12-01

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

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.