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Sample records for affecting leaf bronzing

  1. Photosynthesis affects following night leaf conductance in Vicia faba.

    PubMed

    Easlon, Hsien Ming; Richards, James H

    2009-01-01

    Night-time stomatal opening in C(3) plants may result in significant water loss when no carbon gain is possible. The objective of this study was to determine if endogenous patterns of night-time stomatal opening, as reflected in leaf conductance, in Vicia faba are affected by photosynthetic conditions the previous day. Reducing photosynthesis with low light or low CO(2) resulted in reduced night-time stomatal opening the following night, irrespective of the effects on daytime stomatal conductance. Likewise, increasing photosynthesis with enriched CO(2) levels resulted in increased night-time stomatal opening the following night. Reduced night-time stomatal opening was not the result of an inability to regulate stomatal aperture as leaves with reduced night-time stomatal opening were capable of greater night-time opening when exposed to low CO(2). After acclimating plants to long or short days, it was found that night-time leaf conductance was greater in plants acclimated to short days, and associated with greater leaf starch and nitrate accumulation, both of which may affect night-time guard cell osmotic potential. Direct measurement of guard cell contents during endogenous night-time stomatal opening will help identify the mechanism of the effect of daytime photosynthesis on subsequent night-time stomatal regulation. PMID:19076531

  2. Black leaf streak disease affects starch metabolism in banana fruit.

    PubMed

    Saraiva, Lorenzo de Amorim; Castelan, Florence Polegato; Shitakubo, Renata; Hassimotto, Neuza Mariko Aymoto; Purgatto, Eduardo; Chillet, Marc; Cordenunsi, Beatriz Rosana

    2013-06-12

    Black leaf streak disease (BLSD), also known as black sigatoka, represents the main foliar disease in Brazilian banana plantations. In addition to photosynthetic leaf area losses and yield losses, this disease causes an alteration in the pre- and postharvest behavior of the fruit. The aim of this work was to investigate the starch metabolism of fruits during fruit ripening from plants infected with BLSD by evaluating carbohydrate content (i.e., starch, soluble sugars, oligosaccharides, amylose), phenolic compound content, phytohormones, enzymatic activities (i.e., starch phosphorylases, α- and β-amylase), and starch granules. The results indicated that the starch metabolism in banana fruit ripening is affected by BLSD infection. Fruit from infested plots contained unusual amounts of soluble sugars in the green stage and smaller starch granules and showed a different pattern of superficial degradation. Enzymatic activities linked to starch degradation were also altered by the disease. Moreover, the levels of indole-acetic acid and phenolic compounds indicated an advanced fruit physiological age for fruits from infested plots. PMID:23692371

  3. Bronze diabetes.

    PubMed

    L N, Akshatha; Shenoy, Mamatha T; Yadav, Charu; M S, Rukmini; Kamath, Nutan

    2015-04-01

    Thalassemia is a group of disorders characterized by deficient production of the β-globin sub unit of hemoglobin. The mandatory blood transfusions in patients with thalassemia to maintain adequate erythrocyte levels, leads to iron overload. The prevalence of diabetes in patients with thalassemia varies from 6 to 14%. We here by present a known case of thalassemia major in an 18 year old boy. He was diagnosed with thalassemia before the age of one year and is on regular blood transfusion every two weeks since then. The repeated blood transfusion is one of the common causes for haemochromatosis. Iron overload initially leads to glucose abnormalities such as insulin resistance and hyperinsulinemia, which is followed by impaired secretion of insulin. Diagnosed as a case of bronze diabetes, this patient is on insulin therapy for the last two years. Currently the patient is on iron chelation therapy at Kasturba Medical College Hospital, Mangalore, Karnataka, India. PMID:26023548

  4. Does leaf manipulation affect leaf appearance in italian ryegrass (Lolium multiflorum Lam.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mechanical stimuli such as rubbing, shaking, or flexing plants can alter their growth rates and morphologies. Plant response to mechanical stress can result in delayed plant growth, reduced leaf size, shorten and thicken stems, and reduced yields. Repeated measurements, such as leaf counting or me...

  5. Frequent Occurrence of Tomato Leaf Curl New Delhi Virus in Cotton Leaf Curl Disease Affected Cotton in Pakistan

    PubMed Central

    Zaidi, Syed Shan-e-Ali; Shafiq, Muhammad; Amin, Imran; Scheffler, Brian E.; Scheffler, Jodi A.; Briddon, Rob W.; Mansoor, Shahid

    2016-01-01

    Cotton leaf curl disease (CLCuD) is the major biotic constraint to cotton production on the Indian subcontinent, and is caused by monopartite begomoviruses accompanied by a specific DNA satellite, Cotton leaf curl Multan betasatellite (CLCuMB). Since the breakdown of resistance against CLCuD in 2001/2002, only one virus, the “Burewala” strain of Cotton leaf curl Kokhran virus (CLCuKoV-Bur), and a recombinant form of CLCuMB have consistently been identified in cotton across the major cotton growing areas of Pakistan. Unusually a bipartite isolate of the begomovirus Tomato leaf curl virus was identified in CLCuD-affected cotton recently. In the study described here we isolated the bipartite begomovirus Tomato leaf curl New Delhi virus (ToLCNDV) from CLCuD-affected cotton. To assess the frequency and geographic occurrence of ToLCNDV in cotton, CLCuD-symptomatic cotton plants were collected from across the Punjab and Sindh provinces between 2013 and 2015. Analysis of the plants by diagnostic PCR showed the presence of CLCuKoV-Bur in all 31 plants examined and ToLCNDV in 20 of the samples. Additionally, a quantitative real-time PCR analysis of the levels of the two viruses in co-infected plants suggests that coinfection of ToLCNDV with the CLCuKoV-Bur/CLCuMB complex leads to an increase in the levels of CLCuMB, which encodes the major pathogenicity (symptom) determinant of the complex. The significance of these results are discussed. PMID:27213535

  6. Frequent Occurrence of Tomato Leaf Curl New Delhi Virus in Cotton Leaf Curl Disease Affected Cotton in Pakistan.

    PubMed

    Zaidi, Syed Shan-E-Ali; Shafiq, Muhammad; Amin, Imran; Scheffler, Brian E; Scheffler, Jodi A; Briddon, Rob W; Mansoor, Shahid

    2016-01-01

    Cotton leaf curl disease (CLCuD) is the major biotic constraint to cotton production on the Indian subcontinent, and is caused by monopartite begomoviruses accompanied by a specific DNA satellite, Cotton leaf curl Multan betasatellite (CLCuMB). Since the breakdown of resistance against CLCuD in 2001/2002, only one virus, the "Burewala" strain of Cotton leaf curl Kokhran virus (CLCuKoV-Bur), and a recombinant form of CLCuMB have consistently been identified in cotton across the major cotton growing areas of Pakistan. Unusually a bipartite isolate of the begomovirus Tomato leaf curl virus was identified in CLCuD-affected cotton recently. In the study described here we isolated the bipartite begomovirus Tomato leaf curl New Delhi virus (ToLCNDV) from CLCuD-affected cotton. To assess the frequency and geographic occurrence of ToLCNDV in cotton, CLCuD-symptomatic cotton plants were collected from across the Punjab and Sindh provinces between 2013 and 2015. Analysis of the plants by diagnostic PCR showed the presence of CLCuKoV-Bur in all 31 plants examined and ToLCNDV in 20 of the samples. Additionally, a quantitative real-time PCR analysis of the levels of the two viruses in co-infected plants suggests that coinfection of ToLCNDV with the CLCuKoV-Bur/CLCuMB complex leads to an increase in the levels of CLCuMB, which encodes the major pathogenicity (symptom) determinant of the complex. The significance of these results are discussed. PMID:27213535

  7. Benzothiadiazole affects the leaf proteome in arctic bramble (Rubus arcticus).

    PubMed

    Hukkanen, Anne; Kokko, Harri; Buchala, Antony; Häyrinen, Jukka; Kärenlampi, Sirpa

    2008-11-01

    Benzothiadiazole (BTH) induces resistance to the downy mildew pathogen, Peronospora sparsa, in arctic bramble, but the basis for the BTH-induced resistance is unknown. Arctic bramble cv. Mespi was treated with BTH to study the changes in leaf proteome and to identify proteins with a putative role in disease resistance. First, BTH induced strong expression of one PR-1 protein isoform, which was also induced by salicylic acid (SA). The PR-1 was responsive to BTH and exogenous SA despite a high endogenous SA content (20-25 microg/g fresh weight), which increased to an even higher level after treatment with BTH. Secondly, a total of 792 protein spots were detected in two-dimensional gel electrophoresis, eight proteins being detected solely in the BTH-treated plants. BTH caused up- or down-regulation of 72 and 31 proteins, respectively, of which 18 were tentatively identified by mass spectrometry. The up-regulation of flavanone-3-hydroxylase, alanine aminotransferase, 1-aminocyclopropane-1-carboxylate oxidase, PR-1 and PR-10 proteins may partly explain the BTH-induced resistance against P. sparsa. Other proteins with changes in intensity appear to be involved in, for example, energy metabolism and protein processing. The decline in ATP synthase, triosephosphate isomerase, fructose bisphosphate aldolase and glutamine synthetase suggests that BTH causes significant changes in primary metabolism, which provides one possible explanation for the decreased vegetative growth of foliage and rhizome observed in BTH-treated plants. PMID:19019008

  8. Developmental changes in carbon and nitrogen metabolism affect tea quality in different leaf position.

    PubMed

    Li, Zhi-Xin; Yang, Wei-Jun; Ahammed, Golam Jalal; Shen, Chen; Yan, Peng; Li, Xin; Han, Wen-Yan

    2016-09-01

    Leaf position represents a specific developmental stage that influences both photosynthesis and respiration. However, the precise relationships between photosynthesis and respiration in different leaf position that affect tea quality are largely unknown. Here, we show that the effective quantum yield of photosystem II [ΦPSⅡ] as well as total chlorophyll concentration (TChl) of tea leaves increased gradually with leaf maturity. Moreover, respiration rate (RR) together with total nitrogen concentration (TN) decreased persistently, but total carbon remained unchanged during leaf maturation. Analyses of major N-based organic compounds revealed that decrease in TN was attributed to a significant decrease in the concentration of caffeine and amino acids (AA) in mature leaves. Furthermore, soluble sugar (SS) decreased, but starch concentration increased with leaf maturity, indicating that source-sink relationship was altered during tea leaf development. Detailed correlation analysis showed that ΦPSⅡ was negatively correlated with RR, SS, starch, tea polyphenol (TP), total catechins and TN, but positively correlated with TChl; while RR was positively correlated with TN, SS, TP and caffeine, but negatively correlated with TChl and starch concentrations. Our results suggest that biosynthesis of chlorophyll, catechins and polyphenols is closely associated with photosynthesis and respiration in different leaf position that greatly influences the relationship between primary and secondary metabolism in tea plants. PMID:27380366

  9. Leaf optical properties are affected by the location and type of deposited biominerals.

    PubMed

    Klančnik, Katja; Vogel-Mikuš, Katarina; Kelemen, Mitja; Vavpetič, Primož; Pelicon, Primož; Kump, Peter; Jezeršek, David; Gianoncelli, Alessandra; Gaberščik, Alenka

    2014-11-01

    This study aimed to relate the properties of incrusted plant tissues and structures as well as biomineral concentrations and localization with leaf reflectance and transmittance spectra from 280nm to 880nm in the grasses Phragmites australis, Phalaris arundinacea, Molinia caerulea and Deschampsia cespitosa, and the sedge Carex elata. Redundancy analysis revealed that prickle-hair length on adaxial surface and thickness of lower epidermis exerted significant effects in P. australis; prickle-hair density at abaxial leaf surface and thickness of epidermis on adaxial leaf surface in P. arundinacea; thickness of epidermis on adaxial leaf in D. cespitosa; prickle-hair density on adaxial leaf surface and thickness of cuticle in M. caerulea; and prickle-hair density on adaxial leaf surface and cuticle thickness of the lower side in C. elata. Micro-PIXE and LEXRF elemental localization analysis show that all of these structures and tissues are encrusted by Si and/or by Ca. Reflectance spectra were significantly affected by the Ca concentrations, while Si and Mg concentrations and the Ca concentrations significantly affected transmittance spectra. High concentrations of Mg were detected in epidermal vacuoles of P. arundinacea, M. caerulea and D. cespitosa. Al co-localises with Si in the cuticle, epidermis and/or prickle hairs. PMID:25194526

  10. Auxin and LANCEOLATE affect leaf shape in tomato via different developmental processes.

    PubMed

    Ben-Gera, Hadas; Ori, Naomi

    2012-10-01

    Elaboration of a complex leaves depends on the morphogenetic activity of a specific tissue at the leaf margin termed marginal-blastozon (MB). In tomato (Solanum lycopersicym), prolonged activity of the MB leads to the development of compound leaves. The activity of the MB is restricted by the TCP transcription factor LANCEOLATE (LA). Plants harboring the dominant LA mutant allele La-2 have simple leaves with a uniform blade. Conversely, leaves of pFIL > > miR319 are compound and grow indeterminately in their margins due to leaf overexpression of miR319, a negative regulator of LA and additional miR319-sensitive genes. We have recently shown that the auxin-response sensor DR5::VENUS marks and precedes leaflet initiation events in the MB. Mutations in ENTIRE (E), an auxin signal inhibitor from the Aux/IAA family, lead to the expansion of the DR5::VENUS signal to throughout the leaf-primordia margin, and to a simplified leaf phenotype. Here, we examined the interaction between auxin, E, and LA in tomato leaf development. In La-2 leaf primordia, the auxin signal is very weak and is diffused to throughout the leaf margin, suggesting that auxin acts within the developmental-context of MB activity, which is controlled by LA. e La-2 double mutants showed an enhanced simple leaf phenotype and e pFIL > > miR319 leaves initiated less leaflets than wild-type, but their margins showed continuous growth. These results suggest that E and auxin affect leaflet initiation within the context of the extended MB activity, but their influence on the extent of indeterminate growth of the leaf is minor. PMID:22902691

  11. Human brains found in a fire-affected 4000-years old Bronze Age tumulus layer rich in soil alkalines and boron in Kutahya, Western Anatolia.

    PubMed

    Altinoz, M A; Ince, B; Sav, A; Dincer, A; Cengiz, S; Mercan, S; Yazici, Z; Bilgen, M N

    2014-02-01

    Undecomposed human bodies and organs always attracted interest in terms of understanding biological tissue stability and immortality. Amongst these, cases of natural mummification found in glaciers, bog sediments and deserts caused even more attention. In 2010, an archeological excavation of a Bronze Age layer in a tumulus near the Western Anatolia city Kütahya revealed fire affected regions with burnt human skeletons and charred wooden objects. Inside of the cracked skulls, undecomposed brains were discernible. To analyze the burial taphonomy of the rare phenomenon of brain preservation, we analyzed brains, bone, teeth and surrounding soils elements using Inductively Coupled Plasma-Mass Spectrometer (ICP-MS). Adipocere formation or saponification of postmortem tissue fat requires high levels of alkalinity and especially potassium. Indeed, ICP-MS analysis of the brain, teeth and bone and also of the surrounding soil revealed high levels of potassium, magnesium, aluminum and boron, which are compatible with the famous role of Kütahya in tile production with its soil containing high level of alkalines and tile-glazing boron. Fatty acid chromatography revealed simultaneous saturation of fats and protection of fragile unsaturated fatty acids consistent with soil-presence of both pro-oxidant and anti-oxidant trace metals. Computerized tomography revealed protection of diencephalic, metencephalic and occipital tissue in one of the best-preserved specimens. Boron was previously found as an intentional preservative of Tutankhamen and Deir el Bahari mummies. Here, in natural soil with its insect-repellant, anti-bacterial and fire-resistance qualities it may be a factor to preserve heat-affected brains as almost bioporcellain specimens. PMID:24060546

  12. Factors affecting survival of bacteriophage on tomato leaf surfaces.

    PubMed

    Iriarte, F B; Balogh, B; Momol, M T; Smith, L M; Wilson, M; Jones, J B

    2007-03-01

    The ability of bacteriophage to persist in the phyllosphere for extended periods is limited by many factors, including sunlight irradiation, especially in the UV zone, temperature, desiccation, and exposure to copper bactericides. The effects of these factors on persistence of phage and formulated phage (phage mixed with skim milk) were evaluated. In field studies, copper caused significant phage reduction if applied on the day of phage application but not if applied 4 or 7 days in advance. Sunlight UV was evaluated for detrimental effects on phage survival on tomato foliage in the field. Phage was applied in the early morning, midmorning, early afternoon, and late evening, while UVA plus UVB irradiation and phage populations were monitored. The intensity of UV irradiation positively correlated with phage population decline. The protective formulation reduced the UV effect. In order to demonstrate direct effects of UV, phage suspensions were exposed to UV irradiation and assayed for effectiveness against bacterial spot of tomato. UV significantly reduced phage ability to control bacterial spot. Ambient temperature had a pronounced effect on nonformulated phage but not on formulated phages. The effects of desiccation and fluorescent light illumination on phage were investigated. Desiccation caused a significant but only slight reduction in phage populations after 60 days, whereas fluorescent light eliminated phages within 2 weeks. The protective formulation eliminated the reduction caused by both of these factors. Phage persistence was dramatically affected by UV, while the other factors had less pronounced effects. Formulated phage reduced deleterious effects of the studied environmental factors. PMID:17259361

  13. Habitat, food, and climate affecting leaf litter anuran assemblages in an Atlantic Forest remnant

    NASA Astrophysics Data System (ADS)

    Rievers, Camila Rabelo; Pires, Maria Rita Silvério; Eterovick, Paula Cabral

    2014-07-01

    Leaf litter anuran assemblages include both species that have terrestrial development and species that, during the breeding season, aggregate around bodies of water where their tadpoles develop. The resources used by these two groups in the leaf litter are likely to differ, as well as their sampled species richness, abundance and biomass as resource availability changes. We conducted a 12-month survey of leaf litter anuran assemblages at three forest areas in the largest Atlantic Forest remnant in the state of Minas Gerais in southeastern Brazil. Each month we estimated, based on capture rates, anuran species richness, abundance, and biomass as assemblage descriptors. We also measured variables that could potentially affect these descriptors in space and time: invertebrate litter fauna (abundance and richness of taxa), leaf litter biomass, and microclimatic conditions (air humidity, air and soil temperature, soil water content, and rainfall). We tested for differences in these variables among areas. We used general linear models to search for the variables that best explained variation in anuran abundance (based on capture rates) throughout the year. We analyzed species with terrestrial development (TD) and with aquatic larvae (AL) separately. We recorded 326 anurans of 15 species. Sampled anuran abundance (correlated to species richness and biomass) was explained by air humidity and/or invertebrate abundance for species with TD, and by soil water content or air humidity and leaf litter biomass for species with AL. The variability in the results of studies on leaf litter frogs that try to find variables to explain changes in community descriptors may be due to spatial variation of resources among areas and also to the fact that TD and AL species are frequently analyzed together, when in fact they are likely to show different responses to resources present in the leaf litter habitat, reflected on capture rates.

  14. Citrus Leaf Volatiles as Affected by Developmental Stage and Genetic Type

    PubMed Central

    Azam, Muhammad; Jiang, Qian; Zhang, Bo; Xu, Changjie; Chen, Kunsong

    2013-01-01

    Major volatiles from young and mature leaves of different citrus types were analyzed by headspace-solid phase microextraction (HS-SPME)-GC-MS. A total of 123 components were identified form nine citrus cultivars, including nine aldehydes, 19 monoterpene hydrocarbons, 27 oxygenated monoterpenes, 43 sesquiterpene hydrocarbons, eight oxygenated sesquiterpenes, two ketones, six esters and nine miscellaneous. Young leaves produced higher amounts of volatiles than mature leaves in most cultivars. The percentage of aldehyde and monoterpene hydrocarbons increased, whilst oxygenated monoterpenes and sesquiterpenes compounds decreased during leaf development. Linalool was the most abundant compound in young leaves, whereas limonene was the chief component in mature ones. Notably, linalool content decreased, while limonene increased, during leaf development in most cultivars. Leaf volatiles were also affected by genetic types. A most abundant volatile in one or several genotypes can be absent in another one(s), such as limonene in young leaves of lemon vs. Satsuma mandarin and β-terpinene in mature leaves of three genotypes vs. the other four. Compositional data was subjected to multivariate statistical analysis, and variations in leaf volatiles were identified and clustered into six groups. This research determining the relationship between production of major volatiles from different citrus varieties and leaf stages could be of use for industrial and culinary purposes. PMID:23994837

  15. Root cooling strongly affects diel leaf growth dynamics, water and carbohydrate relations in Ricinus communis.

    PubMed

    Poiré, Richard; Schneider, Heike; Thorpe, Michael R; Kuhn, Arnd J; Schurr, Ulrich; Walter, Achim

    2010-03-01

    In laboratory and greenhouse experiments with potted plants, shoots and roots are exposed to temperature regimes throughout a 24 h (diel) cycle that can differ strongly from the regime under which these plants have evolved. In the field, roots are often exposed to lower temperatures than shoots. When the root-zone temperature in Ricinus communis was decreased below a threshold value, leaf growth occurred preferentially at night and was strongly inhibited during the day. Overall, leaf expansion, shoot biomass growth, root elongation and ramification decreased rapidly, carbon fluxes from shoot to root were diminished and carbohydrate contents of both root and shoot increased. Further, transpiration rate was not affected, yet hydrostatic tensions in shoot xylem increased. When root temperature was increased again, xylem tension reduced, leaf growth recovered rapidly, carbon fluxes from shoot to root increased, and carbohydrate pools were depleted. We hypothesize that the decreased uptake of water in cool roots diminishes the growth potential of the entire plant - especially diurnally, when the growing leaf loses water via transpiration. As a consequence, leaf growth and metabolite concentrations can vary enormously, depending on root-zone temperature and its heterogeneity inside pots. PMID:19968824

  16. Tadpoles of Early Breeding Amphibians are Negatively Affected by Leaf Litter From Invasive Chinese Tallow Trees

    NASA Astrophysics Data System (ADS)

    Leonard, N. E.

    2005-05-01

    As wetlands are invaded by Chinese tallow trees (Triadica sebifera), native trees are displaced and detrital inputs to amphibian breeding ponds are altered. I used a mesocosm experiment to examine the effect of Chinese tallow leaf litter on the survival to, size at, and time to metamorphosis of amphibian larvae. Fifty 1000-L cattle watering tanks were treated with 1500 g dry weight of one of five leaf litter treatments: Chinese tallow, laurel oak (Quercus laurifolia), water tupelo (Nyssa aquatica), slash pine (Pinus elliottii), or a 3:1:1:1 mixture. Each tank received 45 tadpoles of Pseudacris feriarum, Bufo terrestris, and Hyla cinerea in sequence according to their natural breeding phonologies. Every Pseudacris feriarum and Bufo terrestris tadpole exposed to Chinese tallow died prior to metamorphosis. Hyla cinerea survival in tanks with tallow-only was significantly lower than that observed for all other leaf treatments. Hyla cinerea tadpoles from tallow-only and mixed-leaf treatments were larger at metamorphosis and transformed faster than those in tanks with native leaves only. These results suggest that Chinese tallow leaf litter may negatively affect tadpoles of early breeding frogs and that Chinese tallow invasion may change the structure of amphibian communities in temporary ponds.

  17. Bronze rainbow hologram mirrors

    NASA Astrophysics Data System (ADS)

    Dawson, P.

    2006-02-01

    This project draws on holographic embossing techniques, ancient artistic conventions of bronze mirror design and modelling and casting processes to accomplish portraiture of reflection. Laser scanning, 3D computer graphics and holographic imaging are employed to enable a permanent 3D static holographic image to appear integrated with the real-time moving reflection of a viewer's face in a polished bronze disc. The disc and the figure which holds it (caryatid) are cast in bronze from a lost wax model, a technique which has been used for millennia to make personal mirrors. The Caryatid form of bronze mirror which went through many permutations in ancient Egyptian, Greece and Rome shows a plethora of expressive figure poses ranging from sleek nudes to highly embellished multifigure arrangements. The prototype of this series was made for Australian choreographer Graeme Murphy, Artistic Director of the Sydney Dance Company. Each subsequent mirror will be unique in figure and holographic imagery as arranged between artist and subject. Conceptually this project references both the modern experience of viewing mirrors retrieved from ancient tombs, which due to deterioration of the surface no longer reflect, and the functioning of Chinese Magic mirrors, which have the ability to project a predetermined image. Inspired by the metaphorical potential of these mirrors, which do not reflect the immediate reality of the viewer, this bronze hologram mirror series enables each viewer to reflect upon himself or herself observing simultaneously the holographic image and their own partially obliterated reflection.

  18. Seasonal Variability May Affect Microbial Decomposers and Leaf Decomposition More Than Warming in Streams.

    PubMed

    Duarte, Sofia; Cássio, Fernanda; Ferreira, Verónica; Canhoto, Cristina; Pascoal, Cláudia

    2016-08-01

    Ongoing climate change is expected to affect the diversity and activity of aquatic microbes, which play a key role in plant litter decomposition in forest streams. We used a before-after control-impact (BACI) design to study the effects of warming on a forest stream reach. The stream reach was divided by a longitudinal barrier, and during 1 year (ambient year) both stream halves were at ambient temperature, while in the second year (warmed year) the temperature in one stream half was increased by ca. 3 °C above ambient temperature (experimental half). Fine-mesh bags containing oak (Quercus robur L.) leaves were immersed in both stream halves for up to 60 days in spring and autumn of the ambient and warmed years. We assessed leaf-associated microbial diversity by denaturing gradient gel electrophoresis and identification of fungal conidial morphotypes and microbial activity by quantifying leaf mass loss and productivity of fungi and bacteria. In the ambient year, no differences were found in leaf decomposition rates and microbial productivities either between seasons or stream halves. In the warmed year, phosphorus concentration in the stream water, leaf decomposition rates, and productivity of bacteria were higher in spring than in autumn. They did not differ between stream halves, except for leaf decomposition, which was higher in the experimental half in spring. Fungal and bacterial communities differed between seasons in both years. Seasonal changes in stream water variables had a greater impact on the activity and diversity of microbial decomposers than a warming regime simulating a predicted global warming scenario. PMID:27193000

  19. Evidence for mild sediment Pb contamination affecting leaf-litter decomposition in a lake.

    PubMed

    Oguma, Andrew Y; Klerks, Paul L

    2015-08-01

    Much work has focused on the effects of metal-contaminated sediment on benthic community structure, but effects on ecosystem functions have received far less attention. Decomposition has been widely used as an integrating metric of ecosystem function in lotic systems, but not for lentic ones. We assessed the relationship between low-level sediment lead (Pb) contamination and leaf-litter decomposition in a lentic system. We measured 30-day weight loss in 30 litter-bags that were deployed along a Pb-contamination gradient in a cypress-forested lake. At each deployment site we also quantified macrobenthos abundance, dissolved oxygen, water depth, sediment organic content, sediment silt/clay content, and both total sediment and porewater concentrations of Cd, Cu, Ni, Pb and Zn. Principal components (PC) analysis revealed a negative relationship between Pb concentration and benthic macroinvertebrate abundance, and this covariation dominated the first PC axis (PC1). Subsequent correlation analyses revealed a negative relationship between PC1 and percent leaf-litter loss. Our results indicate that leaf-litter decomposition was related to sediment Pb and benthic macroinvertebrate abundance. They also showed that ecosystem function may be affected even where sediment Pb concentrations are mostly below threshold-effects sediment quality guidelines--a finding with potential implications for sediment risk assessment. Additionally, the litter-bag technique used in this study showed promise as a tool in risk assessments of metal-contaminated sediments in lentic systems. PMID:26115904

  20. Increasing shrub abundance and N addition in Arctic tundra affect leaf and root litter decomposition differently

    NASA Astrophysics Data System (ADS)

    McLaren, J.; van de Weg, M. J.; Shaver, G. R.; Gough, L.

    2013-12-01

    Changes in global climate have resulted in a ';greening' of the Arctic as the abundance of deciduous shrub species increases. Consequently, not only the living plant community, but also the litter composition changes, which in turn can affect carbon turnover patterns in the Arctic. We examined effects of changing litter composition (both root and leaf litter) on decomposition rates with a litter bag study, and specifically focused on the impact of deciduous shrub Betula nana litter on litter decomposition from two evergreen shrubs (Ledum palustre, and Vaccinium vitis-idaea) and one graminoid (Eriophorum vaginatum) species. Additionally, we investigated how decomposition was affected by nutrient availability by placing the litterbags in an ambient and a fertilized moist acidic tundra environment. Measurements were carried out seasonally over 2 years (after snow melt, mid-growing season, end growing season). We measured litter mass loss over time, as well as the respiration rates (standardized for temperature and moisture) and temperature sensitivity of litter respiration at the time of harvesting the litter bags. For leaves, Betula litter decomposed faster than the other three species, with Eriophorum leaves decomposing the slowest. This pattern was observed for both mass loss and litter respiration rates, although the differences in respiration became smaller over time. Surprisingly, combining Betula with any other species resulted in slower overall weight loss rates than would be predicted based on monoculture weight loss rates. This contrasted with litter respiration at the time of sampling, which showed a positive mixing effect of adding Betula leaf liter to the other species. Apparently, during the first winter months (September - May) Betula litter decomposition is negatively affected by mixing the species and this legacy can still be observed in the total mass loss results later in the year. For root litter there were fewer effects of species identity on root

  1. Frequent Occurrence of Tomato Leaf Curl New Delhi Virus in Cotton Leaf Curl Disease Affected Cotton in Pakistan

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cotton leaf curl disease (CLCuD) in the Indian subcontinent is associated with several distinct monopartite begomoviruses and DNA satellites. However, only a single begomovirus was associated with breakdown of resistance against CLCuD in previously resistant cotton varieties. The monopartite begomov...

  2. Does Initial Leaf Chemistry Affect the Contribution of Insects, Fungi, and Bacteria to Leaf Breakdown in a Lowland Tropical Stream?

    NASA Astrophysics Data System (ADS)

    Ardon, M.; Pringle, C. M.

    2005-05-01

    We examined effects of initial leaf chemistry of six common riparian species on the relative contribution of fungi, bacteria, and invertebrates to leaf breakdown in a lowland stream in Costa Rica. We hypothesized that fungi and bacteria would contribute more to the breakdown of species with low concentrations of secondary (tannins and phenolics) and structural (cellulose and lignin) compounds, while invertebrates would be more important in the processing of species with high concentrations of secondary and structural compounds. We incubated single species leaf bags of six common riparian species, representing a range in secondary and structural compounds, in a third-order stream at La Selva Biological Station, Costa Rica. We measured leaf chemistry during the breakdown process. We determined fungal biomass using ergosterol methods, bacteria using DAPI counts, and invertebrate biomass using length-weight regressions. We then used biomass estimates for each group to determine their contribution to the overall breakdown process. Breakdown rates ranged from very fast (Trema integerima, k = 0.23 day-1) to slow (Zygia longifolia , k = 0.011 day-1). While analyses are still under way, preliminary results support our initial hypothesis that fungi contribute more to the break down of leaves from tree species with low concentrations of secondary and structural compounds.

  3. Diversity and Composition of the Leaf Mycobiome of Beech (Fagus sylvatica) Are Affected by Local Habitat Conditions and Leaf Biochemistry

    PubMed Central

    Unterseher, Martin; Siddique, Abu Bakar; Brachmann, Andreas; Peršoh, Derek

    2016-01-01

    Comparative investigations of plant-associated fungal communities (mycobiomes) in distinct habitats and under distinct climate regimes have been rarely conducted in the past. Nowadays, high-throughput sequencing allows routine examination of mycobiome responses to environmental changes and results at an unprecedented level of detail. In the present study, we analysed Illumina-generated fungal ITS1 sequences from European beech (Fagus sylvatica) originating from natural habitats at two different altitudes in the German Alps and from a managed tree nursery in northern Germany. In general, leaf-inhabiting mycobiome diversity and composition correlated significantly with the origin of the trees. Under natural condition the mycobiome was more diverse at lower than at higher elevation, whereas fungal diversity was lowest in the artificial habitat of the tree nursery. We further identified significant correlation of leaf chlorophylls and flavonoids with both habitat parameters and mycobiome biodiversity. The present results clearly point towards a pronounced importance of local stand conditions for the structure of beech leaf mycobiomes and for a close interrelation of phyllosphere fungi and leaf physiology. PMID:27078859

  4. Diversity and Composition of the Leaf Mycobiome of Beech (Fagus sylvatica) Are Affected by Local Habitat Conditions and Leaf Biochemistry.

    PubMed

    Unterseher, Martin; Siddique, Abu Bakar; Brachmann, Andreas; Peršoh, Derek

    2016-01-01

    Comparative investigations of plant-associated fungal communities (mycobiomes) in distinct habitats and under distinct climate regimes have been rarely conducted in the past. Nowadays, high-throughput sequencing allows routine examination of mycobiome responses to environmental changes and results at an unprecedented level of detail. In the present study, we analysed Illumina-generated fungal ITS1 sequences from European beech (Fagus sylvatica) originating from natural habitats at two different altitudes in the German Alps and from a managed tree nursery in northern Germany. In general, leaf-inhabiting mycobiome diversity and composition correlated significantly with the origin of the trees. Under natural condition the mycobiome was more diverse at lower than at higher elevation, whereas fungal diversity was lowest in the artificial habitat of the tree nursery. We further identified significant correlation of leaf chlorophylls and flavonoids with both habitat parameters and mycobiome biodiversity. The present results clearly point towards a pronounced importance of local stand conditions for the structure of beech leaf mycobiomes and for a close interrelation of phyllosphere fungi and leaf physiology. PMID:27078859

  5. Do variations in leaf phenology affect radial growth variations in Fagus sylvatica?

    NASA Astrophysics Data System (ADS)

    Čufar, Katarina; De Luis, Martin; Prislan, Peter; Gričar, Jožica; Črepinšek, Zalika; Merela, Maks; Kajfež-Bogataj, Lučka

    2015-08-01

    We used a dendrochronological and leaf phenology network of European beech ( Fagus sylvatica) in Slovenia, a transitional area between Mediterranean, Alpine and continental climatic regimes, for the period 1955-2007 to test whether year to year variations in leaf unfolding and canopy duration (i.e. time between leaf unfolding and colouring) influence radial growth (annual xylem production and tree ring widths) and if such influences are more pronounced at higher altitudes. We showed that variability in leaf phenology has no significant effect on variations in radial growth. The results are consistent in the entire region, irrespective of the climatic regime or altitude, although previous studies have shown that leaf phenology and tree ring variation depend on altitude. The lack of relationship between year to year variability in leaf phenology and radial growth may suggest that earlier leaf unfolding—as observed in a previous study—probably does not cause increased tree growth rates in beech in Slovenia.

  6. Prior Hydrologic Disturbance Affects Competition between Aedes Mosquitoes via Changes in Leaf Litter

    PubMed Central

    Smith, Cassandra D.; Freed, T. Zachary; Leisnham, Paul T.

    2015-01-01

    Allochthonous leaf litter is often the main resource base for invertebrate communities in ephemeral water-filled containers, and detritus quality can be affected by hydrologic conditions. The invasive mosquito Aedes albopictus utilizes container habitats for its development where it competes as larvae for detritus and associated microorganisms with the native Aedes triseriatus. Different hydrologic conditions that containers are exposed to prior to mosquito utilization affect litter decay and associated water quality. We tested the hypothesis that larval competition between A. albopictus and A. triseriatus would be differentially affected by prior hydrologic conditions. Experimental microcosms provisioned with Quercus alba L. litter were subjected to one of three different hydrologic treatments prior to the addition of water and mosquito larvae: dry, flooded, and a wet/dry cycle. Interspecific competition between A. albopictus and A. triseriatus was mediated by hydrologic treatment, and was strongest in the dry treatment vs. the flooded or wet/dry treatments. Aedes triseriatus estimated rate of population change (λ') was lowest in the dry treatment. Aedes albopictus λ' was unaffected by hydrologic treatment, and was on average always increasing (i.e., > 1). Aedes triseriatus λ' was affected by the interaction of hydrologic treatment with interspecific competition, and was on average declining (i.e., < 1.0), at the highest interspecific densities in the dry treatment. Dry treatment litter had the slowest decay rate and leached the highest concentration of tannin-lignin, but supported more total bacteria than the other treatments. These results suggest that dry conditions negatively impact A. triseriatus population performance and may result in the competitive exclusion of A. triseriatus by A. albopictus, possibly by reducing microbial taxa that Aedes species browse. Changing rainfall patterns with climate change are likely to affect competition between A

  7. Prior Hydrologic Disturbance Affects Competition between Aedes Mosquitoes via Changes in Leaf Litter.

    PubMed

    Smith, Cassandra D; Freed, T Zachary; Leisnham, Paul T

    2015-01-01

    Allochthonous leaf litter is often the main resource base for invertebrate communities in ephemeral water-filled containers, and detritus quality can be affected by hydrologic conditions. The invasive mosquito Aedes albopictus utilizes container habitats for its development where it competes as larvae for detritus and associated microorganisms with the native Aedes triseriatus. Different hydrologic conditions that containers are exposed to prior to mosquito utilization affect litter decay and associated water quality. We tested the hypothesis that larval competition between A. albopictus and A. triseriatus would be differentially affected by prior hydrologic conditions. Experimental microcosms provisioned with Quercus alba L. litter were subjected to one of three different hydrologic treatments prior to the addition of water and mosquito larvae: dry, flooded, and a wet/dry cycle. Interspecific competition between A. albopictus and A. triseriatus was mediated by hydrologic treatment, and was strongest in the dry treatment vs. the flooded or wet/dry treatments. Aedes triseriatus estimated rate of population change (λ') was lowest in the dry treatment. Aedes albopictus λ' was unaffected by hydrologic treatment, and was on average always increasing (i.e., > 1). Aedes triseriatus λ' was affected by the interaction of hydrologic treatment with interspecific competition, and was on average declining (i.e., < 1.0), at the highest interspecific densities in the dry treatment. Dry treatment litter had the slowest decay rate and leached the highest concentration of tannin-lignin, but supported more total bacteria than the other treatments. These results suggest that dry conditions negatively impact A. triseriatus population performance and may result in the competitive exclusion of A. triseriatus by A. albopictus, possibly by reducing microbial taxa that Aedes species browse. Changing rainfall patterns with climate change are likely to affect competition between A

  8. Epigenetic Mutation of RAV6 Affects Leaf Angle and Seed Size in Rice.

    PubMed

    Zhang, Xiangqian; Sun, Jing; Cao, Xiaofeng; Song, Xianwei

    2015-11-01

    Heritable epigenetic variants of genes, termed epialleles, can broaden genetic and phenotypic diversity in eukaryotes. Epialleles may also provide a new source of beneficial traits for crop breeding, but very few epialleles related to agricultural traits have been identified in crops. Here, we identified Epi-rav6, a gain-of-function epiallele of rice (Oryza sativa) RELATED TO ABSCISIC ACID INSENSITIVE3 (ABI3)/VIVIPAROUS1 (VP1) 6 (RAV6), which encodes a B3 DNA-binding domain-containing protein. The Epi-rav6 plants show larger lamina inclination and smaller grain size; these agronomically important phenotypes are inherited in a semidominant manner. We did not find nucleotide sequence variation of RAV6. Instead, we found hypomethylation in the promoter region of RAV6, which caused ectopic expression of RAV6 in Epi-rav6 plants. Bisulfite analysis revealed that cytosine methylation of four CG and two CNG loci within a continuous 96-bp region plays essential roles in regulating RAV6 expression; this region contains a conserved miniature inverted repeat transposable element transposon insertion in cultivated rice genomes. Overexpression of RAV6 in the wild type phenocopied the Epi-rav6 phenotype. The brassinosteroid (BR) receptor BR INSENSITIVE1 and BR biosynthetic genes EBISU DWARF, DWARF11, and BR-DEFICIENT DWARF1 were ectopically expressed in Epi-rav6 plants. Also, treatment with a BR biosynthesis inhibitor restored the leaf angle defects of Epi-rav6 plants. This indicates that RAV6 affects rice leaf angle by modulating BR homeostasis and demonstrates an essential regulatory role of epigenetic modification on a key gene controlling important agricultural traits. Thus, our work identifies a unique rice epiallele, which may represent a common phenomenon in complex crop genomes. PMID:26351308

  9. Alterations in lignin content and phenylpropanoids pathway in date palm (Phoenix dactylifera L.) tissues affected by brittle leaf disease.

    PubMed

    Saidi, Mohammed Najib; Bouaziz, Donia; Hammami, Ines; Namsi, Ahmed; Drira, Noureddine; Gargouri-Bouzid, Radhia

    2013-10-01

    Brittle leaf disease or Maladie de la Feuille Cassante (MFC) is a lethal disorder of date palm that has assumed epidemic proportions in the oases of Tunisia and Algeria. No pathogen could ever be associated with the disease, while leaflets of affected palms have been previously shown to be deficient in manganese. The work reported here aims to understand the biochemical basis of the date palm response to this disorder. Since the typical disease symptom is the leaf fragility, we have investigated lignin content in leaves and roots. Strong decrease in total lignin content was observed in affected leaves, while lignin content increased in affected roots. Histochemical analyses showed hyperlignification thicker suberin layer in roots cortical cells. The phenylpropanoids pathway was also disrupted in leaves and roots, cinnamoyl-CoA reductase and cinnamyl-alcohol dehydrogenase gene expression was affected by the disease which severely affects the cell wall integrity. PMID:23987806

  10. The ASYMMETRIC LEAVES Complex Employs Multiple Modes of Regulation to Affect Adaxial-Abaxial Patterning and Leaf Complexity[OPEN

    PubMed Central

    Husbands, Aman Y.; Benkovics, Anna H.; Nogueira, Fabio T.S.; Lodha, Mukesh; Timmermans, Marja C.P.

    2015-01-01

    Flattened leaf architecture is not a default state but depends on positional information to precisely coordinate patterns of cell division in the growing primordium. This information is provided, in part, by the boundary between the adaxial (top) and abaxial (bottom) domains of the leaf, which are specified via an intricate gene regulatory network whose precise circuitry remains poorly defined. Here, we examined the contribution of the ASYMMETRIC LEAVES (AS) pathway to adaxial-abaxial patterning in Arabidopsis thaliana and demonstrate that AS1-AS2 affects this process via multiple, distinct regulatory mechanisms. AS1-AS2 uses Polycomb-dependent and -independent mechanisms to directly repress the abaxial determinants MIR166A, YABBY5, and AUXIN RESPONSE FACTOR3 (ARF3), as well as a nonrepressive mechanism in the regulation of the adaxial determinant TAS3A. These regulatory interactions, together with data from prior studies, lead to a model in which the sequential polarization of determinants, including AS1-AS2, explains the establishment and maintenance of adaxial-abaxial leaf polarity. Moreover, our analyses show that the shared repression of ARF3 by the AS and trans-acting small interfering RNA (ta-siRNA) pathways intersects with additional AS1-AS2 targets to affect multiple nodes in leaf development, impacting polarity as well as leaf complexity. These data illustrate the surprisingly multifaceted contribution of AS1-AS2 to leaf development showing that, in conjunction with the ta-siRNA pathway, AS1-AS2 keeps the Arabidopsis leaf both flat and simple. PMID:26589551

  11. Degradation of monumental bronzes

    NASA Astrophysics Data System (ADS)

    Meakin, John D.; Ames, David L.; Dolske, Donald A.

    Under the United States National Acid Precipitation Assessment Program a metallurgical and corrosion study has been made of sample of the 50 bronze replicas of the Hiker statue cast by the Gorham Foundry, Providence, Rhode Island, between 1906 and 1966. To study corrosion damage on a microscopic scale a technique was developed to take molds of selected features on the statue. The molds were examined by optical and scanning electron microscopy and surface profilometry. The overall approach has the potential for quantitatively monitoring the local corrosion at selected sites over a period of years and also characterizing the impact of conservation procedures. In a parallel research program, run-off samples were taken from selected Brigade Markers in a series of bronze tablets in the Gettysburg National Military Park; parallel rainwater samples were collected. Analysis for pH, metal content and various ion species in the run off yields information on the total rate of corrosion as a function of dry and wet precipitation.

  12. 75 FR 14257 - Pricing for Bronze Medals

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-24

    .... ACTION: Notice. SUMMARY: The United States Mint is announcing the price of the 1\\5/16\\- inch bronze medals, 1\\1/2\\-inch bronze medals and three-inch bronze medals. Beginning March 25, 2010, the 1\\5/16\\-inch bronze medals will be priced at $5.50 each; 1\\1/2\\-inch bronze medals will be priced at $6.00...

  13. Leaf Associated Microbial Activities in a Stream Affected by Acid Mine Drainage

    NASA Astrophysics Data System (ADS)

    Schlief, Jeanette

    2004-11-01

    Microbial activity was assessed on birch leaves and plastic strips during 140 days of exposure at three sites in an acidic stream of the Lusatian post-mining landscape, Germany. The sites differed in their degrees of ochre deposition and acidification. The aim of the study was (1) to follow the microbial activities during leaf colonization, (2) to compare the effect of different environmental conditions on leaf associated microbial activities, and (3) to test the microbial availability of leaf litter in acidic mining waters. The activity peaked after 49 days and subsequently decreased gradually at all sites. A formation of iron plaques on leaf surfaces influenced associated microbial activity. It seemed that these plaques inhibit the microbial availability of leaf litter and serve as a microbial habitat by itself. (

  14. Rolling-leaf14 is a 2OG-Fe (II) oxygenase family protein that modulates rice leaf rolling by affecting secondary cell wall formation in leaves.

    PubMed

    Fang, Likui; Zhao, Fangming; Cong, Yunfei; Sang, Xianchun; Du, Qing; Wang, Dezhong; Li, Yunfeng; Ling, Yinghua; Yang, Zhenglin; He, Guanghua

    2012-06-01

    As an important agronomic trait, leaf rolling in rice (Oryza sativa L.) has attracted much attention from plant biologists and breeders. Moderate leaf rolling increases the amount of photosynthesis in cultivars and hence raises grain yield. Here, we describe the map-based cloning of the gene RL14, which was found to encode a 2OG-Fe (II) oxygenase of unknown function. rl14 mutant plants had incurved leaves because of the shrinkage of bulliform cells on the adaxial side. In addition, rl14 mutant plants displayed smaller stomatal complexes and decreased transpiration rates, as compared with the wild type. Defective development could be rescued functionally by the expression of wild-type RL14. RL14 was transcribed in sclerenchymatous cells in leaves that remained wrapped inside the sheath. In mature leaves, RL14 accumulated mainly in the mesophyll cells that surround the vasculature. Expression of genes related to secondary cell wall formation was affected in rl14-1 mutants, and cellulose and lignin content were altered in rl14-1 leaves. These results reveal that the RL14 gene affects water transport in leaves by affecting the composition of the secondary cell wall. This change in water transport results in water deficiency, which is the major reason for the abnormal shape of the bulliform cells. PMID:22329407

  15. Leaf biomechanical properties in Arabidopsis thaliana polysaccharide mutants affect drought survival.

    PubMed

    Balsamo, Ronald; Boak, Merewyn; Nagle, Kayla; Peethambaran, Bela; Layton, Bradley

    2015-11-26

    Individual sugars are the building blocks of cell wall polysaccharides, which in turn comprise a plant׳s overall architectural structure. But which sugars play the most prominent role in maintaining a plant׳s mechanical stability during large cellular deformations induced by drought? We investigated the individual contributions of several genes that are involved in the synthesis of monosaccharides which are important for cell wall structure. We then measured drought tolerance and mechanical integrity during simulated drought in Arabidopsis thaliana. To assess mechanical properties, we designed a small-scale tensile tester for measuring failure strain, ultimate tensile stress, work to failure, toughness, and elastic modulus of 6-week-old leaves in both hydrated and drought-simulated states. Col-0 mutants used in this study include those deficient in lignin, cellulose, components of hemicellulose such as xylose and fucose, the pectic components arabinose and rhamnose, as well as mutants with enhanced arabinose and total pectin content. We found that drought tolerance is correlated to the mechanical and architectural stability of leaves as they experience dehydration. Of the mutants, S096418 with mutations for reduced xylose and galactose was the least drought tolerant, while the arabinose-altered CS8578 mutants were the least affected by water loss. There were also notable correlations between drought tolerance and mechanical properties in the diminished rhamnose mutant, CS8575 and the dehydrogenase-disrupted S120106. Our findings suggest that components of hemicellulose and pectins affect leaf biomechanical properties and may play an important role in the ability of this model system to survive drought. PMID:26520913

  16. Herbivore-induced maize leaf volatiles affect attraction and feeding behavior of Spodoptera littoralis caterpillars.

    PubMed

    von Mérey, Georg E; Veyrat, Nathalie; D'Alessandro, Marco; Turlings, Ted C J

    2013-01-01

    Plants under herbivore attack emit volatile organic compounds (VOCs) that can serve as foraging cues for natural enemies. Adult females of Lepidoptera, when foraging for host plants to deposit eggs, are commonly repelled by herbivore-induced VOCs, probably to avoid competition and natural enemies. Their larval stages, on the other hand, have been shown to be attracted to inducible VOCs. We speculate that this contradicting behavior of lepidopteran larvae is due to a need to quickly find a new suitable host plant if they have fallen to the ground. However, once they are on a plant they might avoid the sites with fresh damage to limit competition and risk of cannibalism by conspecifics, as well as exposure to natural enemies. To test this we studied the effect of herbivore-induced VOCs on the attraction of larvae of the moth Spodoptera littoralis and on their feeding behavior. The experiments further considered the importance of previous feeding experience on the responses of the larvae. It was confirmed that herbivore-induced VOCs emitted by maize plants are attractive to the larvae, but exposure to the volatiles decreased the growth rate of caterpillars at early developmental stages. Larvae that had fed on maize previously were more attracted by VOCs of induced maize than larvae that had fed on artificial diet. At relatively high concentrations synthetic green leaf volatiles, indicative of fresh damage, also negatively affected the growth rate of caterpillars, but not at low concentrations. In all cases, feeding by the later stages of the larvae was not affected by the VOCs. The results are discussed in the context of larval foraging behavior under natural conditions, where there may be a trade-off between using available host plant signals and avoiding competitors and natural enemies. PMID:23825475

  17. Corrosion and Preservation of Bronze Artifacts.

    ERIC Educational Resources Information Center

    Walker, Robert

    1980-01-01

    Reviews chemical information relating to the corrosion of bronze artifacts. Properties of copper alloys are reviewed, with a thorough discussion of the specialized properties of bronze. Techniques to reduce or eliminate corrosion are listed. (CS)

  18. 21 CFR 73.1646 - Bronze powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Bronze powder. 73.1646 Section 73.1646 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1646 Bronze powder. (a) Identity. (1) The color additive bronze powder is a very fine metallic powder prepared from alloys consisting principally of...

  19. 21 CFR 73.1646 - Bronze powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Bronze powder. 73.1646 Section 73.1646 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1646 Bronze powder. (a) Identity. (1) The color additive bronze powder is a very fine metallic...

  20. 21 CFR 73.1646 - Bronze powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Bronze powder. 73.1646 Section 73.1646 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL LISTING OF COLOR ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1646 Bronze powder. (a) Identity. (1) The color additive bronze powder is a very fine metallic...

  1. 21 CFR 73.1646 - Bronze powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Bronze powder. 73.1646 Section 73.1646 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1646 Bronze powder. (a) Identity. (1) The color additive bronze powder is a very fine metallic powder prepared from alloys consisting principally of...

  2. 21 CFR 73.1646 - Bronze powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Bronze powder. 73.1646 Section 73.1646 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1646 Bronze powder. (a) Identity. (1) The color additive bronze powder is a very fine metallic powder prepared from alloys consisting principally of...

  3. 21 CFR 73.2646 - Bronze powder.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Bronze powder. 73.2646 Section 73.2646 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2646 Bronze powder. (a) Identity and specifications. The color additive bronze powder shall conform in identity and specifications to the requirements of §...

  4. 21 CFR 73.2646 - Bronze powder.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Bronze powder. 73.2646 Section 73.2646 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2646 Bronze powder. (a) Identity and specifications. The color additive bronze powder shall conform in identity and specifications to the requirements of §...

  5. Dynamic spatial patterns of leaf traits affect total respiration on the crown scale

    NASA Astrophysics Data System (ADS)

    Wang, Xiaolin; Zhou, Hongxuan; Han, Fengsen; Li, Yuanzheng; Hu, Dan

    2016-05-01

    Temporal and spatial variations of leaf traits caused conflicting conclusions and great estimating errors of total carbon budget on crown scales. However, there is no effective method to quantitatively describe and study heterogeneous patterns of crowns yet. In this study, dynamic spatial patterns of typical ecological factors on crown scales were investigated during two sky conditions, and CEZs (crown ecological zones) method was developed for spatial crown zoning, within which leaf traits were statistically unchanged. The influencing factors on hourly and spatial variations of leaf dark respiration (Rd) were analysed, and total crown respiration (Rt) was estimated based on patterns of CEZs. The results showed that dynamic spatial patterns of air temperature and light intensity changed significantly by CEZs in special periods and positions, but not continuously. The contributions of influencing factors on variations of Rd changed with crown depth and sky conditions, and total contributions of leaf structural and chemical traits were higher during sunny days than ecological factors, but lower during cloudy days. The estimated errors of Rt may be obviously reduced with CEZs. These results provided some references for scaling from leaves to crown, and technical foundations for expanding lab-control experiments to open field ones.

  6. Dynamic spatial patterns of leaf traits affect total respiration on the crown scale

    PubMed Central

    Wang, Xiaolin; Zhou, Hongxuan; Han, Fengsen; Li, Yuanzheng; Hu, Dan

    2016-01-01

    Temporal and spatial variations of leaf traits caused conflicting conclusions and great estimating errors of total carbon budget on crown scales. However, there is no effective method to quantitatively describe and study heterogeneous patterns of crowns yet. In this study, dynamic spatial patterns of typical ecological factors on crown scales were investigated during two sky conditions, and CEZs (crown ecological zones) method was developed for spatial crown zoning, within which leaf traits were statistically unchanged. The influencing factors on hourly and spatial variations of leaf dark respiration (Rd) were analysed, and total crown respiration (Rt) was estimated based on patterns of CEZs. The results showed that dynamic spatial patterns of air temperature and light intensity changed significantly by CEZs in special periods and positions, but not continuously. The contributions of influencing factors on variations of Rd changed with crown depth and sky conditions, and total contributions of leaf structural and chemical traits were higher during sunny days than ecological factors, but lower during cloudy days. The estimated errors of Rt may be obviously reduced with CEZs. These results provided some references for scaling from leaves to crown, and technical foundations for expanding lab-control experiments to open field ones. PMID:27225586

  7. Dynamic spatial patterns of leaf traits affect total respiration on the crown scale.

    PubMed

    Wang, Xiaolin; Zhou, Hongxuan; Han, Fengsen; Li, Yuanzheng; Hu, Dan

    2016-01-01

    Temporal and spatial variations of leaf traits caused conflicting conclusions and great estimating errors of total carbon budget on crown scales. However, there is no effective method to quantitatively describe and study heterogeneous patterns of crowns yet. In this study, dynamic spatial patterns of typical ecological factors on crown scales were investigated during two sky conditions, and CEZs (crown ecological zones) method was developed for spatial crown zoning, within which leaf traits were statistically unchanged. The influencing factors on hourly and spatial variations of leaf dark respiration (Rd) were analysed, and total crown respiration (Rt) was estimated based on patterns of CEZs. The results showed that dynamic spatial patterns of air temperature and light intensity changed significantly by CEZs in special periods and positions, but not continuously. The contributions of influencing factors on variations of Rd changed with crown depth and sky conditions, and total contributions of leaf structural and chemical traits were higher during sunny days than ecological factors, but lower during cloudy days. The estimated errors of Rt may be obviously reduced with CEZs. These results provided some references for scaling from leaves to crown, and technical foundations for expanding lab-control experiments to open field ones. PMID:27225586

  8. The Liguleless narrow mutation affects proximal distal signaling and leaf growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    How cells acquire competence to differentiate according to position is an essential question in developmental biology. Maize leaves provide a unique opportunity to study positional information. In the developing leaf primordium, a line is drawn across a field of seemingly identical cells. Above the ...

  9. KINETICS OF LEAF TEMPERATURE FLUCTUATION AFFECT ISOPRENE EMISSION FROM RED OAK (QUERCUS RUBRA) LEAVES

    EPA Science Inventory

    Because the rate of isoprene (2-methyl-1,3-butadiene) emission from plants is highly temperature-dependent, we investigated the natural fluctuations on leaf temperature and the effects of rapid temperature change on isoprene emission of red oak (Quercus rubra L.) leaves at the to...

  10. Genome-wide association study of maize identifies genes affecting leaf architecture

    Technology Transfer Automated Retrieval System (TEKTRAN)

    U.S. maize yield has increased eightfold in the past 80 years with half of the improvement attributed to genetics. Changes in maize leaf angle and size provided a basis for more efficient light capture as plant densities increased. Through a genome wide association study (GWAS) of the maize nested a...

  11. Leaf litter quality affects aquatic insect emergence: contrasting patterns from two foundation trees.

    PubMed

    Compson, Zacchaeus G; Adams, Kenneth J; Edwards, Joeseph A; Maestas, Jesse M; Whitham, Thomas G; Marks, Jane C

    2013-10-01

    Reciprocal subsidies between rivers and terrestrial habitats are common where terrestrial leaf litter provides energy to aquatic invertebrates while emerging aquatic insects provide energy to terrestrial predators (e.g., birds, lizards, spiders). We examined how aquatic insect emergence changed seasonally with litter from two foundation riparian trees, whose litter often dominates riparian streams of the southwestern United States: Fremont (Populus fremontii) and narrowleaf (Populus angustifolia) cottonwood. P. fremontii litter is fast-decomposing and lower in defensive phytochemicals (i.e., condensed tannins, lignin) relative to P. angustifolia. We experimentally manipulated leaf litter from these two species by placing them in leaf enclosures with emergence traps attached in order to determine how leaf type influenced insect emergence. Contrary to our initial predictions, we found that packs with slow-decomposing leaves tended to support more emergent insects relative to packs with fast-decomposing leaves. Three findings emerged. Firstly, abundance (number of emerging insects m(-2) day(-1)) was 25% higher on narrowleaf compared to Fremont leaves for the spring but did not differ in the fall, demonstrating that leaf quality from two dominant trees of the same genus yielded different emergence patterns and that these patterns changed seasonally. Secondly, functional feeding groups of emerging insects differed between treatments and seasons. Specifically, in the spring collector-gatherer abundance and biomass were higher on narrowleaf leaves, whereas collector-filterer abundance and biomass were higher on Fremont leaves. Shredder abundance and biomass were higher on narrowleaf leaves in the fall. Thirdly, diversity (Shannon's H') was higher on Fremont leaves in the spring, but no differences were found in the fall, showing that fast-decomposing leaves can support a more diverse, complex emergent insect assemblage during certain times of the year. Collectively, these

  12. Hormonal activity in detached lettuce leaves as affected by leaf water content.

    PubMed

    Aharoni, N; Blumenfeld, A; Richmond, A E

    1977-06-01

    The interrelationship between water deficiency and hormonal makeup in plants was investigated in detached leaves of romaine lettuce (Lactuca sativa L. cv. ;Hazera Yellow'). Water stress was imposed by desiccating the leaves for several hours in light or darkness at different air temperatures and relative humidity. In the course of desiccation, a rise in abscisic acid content and a decline in gibberellin and cytokinin activity were observed by gas-liquid chromatography, by both the barley endosperm bioassay and radioimmunoassay and by the soybean callus bioassay. Gibberellin activity began to decline in the stressed leaves before the rise in abscisic acid, the rate of this decline being positively correlated with the rate of increase in leaf water saturation deficit. Recovery from water stress was effected by immersing the leaf petioles in water while exposing the blades to high relative humidity. This resulted in a decrease in leaf water saturation deficit, a reduction in abscisic acid content, and an increase in gibberellin and cytokinin activity.Application of abscisic acid to the leaves caused partial stomatal closure in turgid lettuce leaves, whereas treatment with gibberellic acid and kinetin of such leaves had no effect on the stomatal aperture. In desiccating leaves, however, gibberellic acid and kinetin treatment considerably retarded stomatal closure, thus enhancing the increase in leaf water saturation deficit. These results suggest that the effect of desiccation in changing leaf hormonal make-up, i.e. a rapid increase in abscisic acid and a decrease in both cytokinin and gibberellin activity, is related to a mechanism designed to curtail water loss under conditions inducing water deficiency. PMID:16660015

  13. Leaf surface chemicals fromNicotiana affecting germination ofPeronospora tabacina (adam) sporangia.

    PubMed

    Kennedy, B S; Nielsen, M T; Severson, R F; Sisson, V A; Stephenson, M K; Jackson, D M

    1992-09-01

    A bioassay was used to evaluate the effects of cuticular leaf components, isolated fromN. tabacum, N. glutinosa (accessions 24 and 24a), and 23other Nicotiana species, on germinationof P. tabacina (blue mold). The leaf surface compounds includedα- andβ-4,8,13,-duvatriene-l,3-diols (DVT-diols), (13-E)-labda-13-ene-8α-,15-diol (labdenediol), (12-Z)-labda-12,14-diene-8α-ol (cis-abienol), (13-R)-labda-8,14-diene-13-ol (manool), 2-hydroxymanool, a mixture of (13-R)-labda-14-ene-8α,13-diol (sclareol), and (13-S)-labda-14-ene-8α,13-diol (episclareol), and various glucose and/or sucrose ester isolates. The above in acetone were applied onto leaf disks of the blue moldsusceptibleN. tabacum cv. TI 1406, which was then inoculated with blue mold sporangia. Estimated IC50 values (inhibitory concentration) were 3.0μg/cm(2) forα-DVT-diol, 2.9μ/cm(2) forβ-DVT-diol, 0.4μg/cm(2) for labdenediol and 4.7μg/cm(2) for the sclareol mixture. Manool, 2-hydroxymanool, andcis-abienol at application rates up to 30μg/cm(2) had little or no effect on sporangium germination. Glucose and/or sucrose ester isolates from the cuticular leaf extracts of 23Nicotiana species and three different fractions fromN. bigelovii were also evaluated for antimicrobial activity at a concentration of 30μg/cm(2). Germination was inhibited by >20% when exposed to sugar esters isolated fromN. acuminata, N. benthamiana, N. attenuata, N. clevelandii, andN. miersii, and accessions 10 and 12 ofN. bigelovii. These results imply that a number of compounds may influence resistance to blue mold in tobacco. PMID:24254279

  14. Leaf damage and gender but not flower damage affect female fitness in Nemophila menziesii (Hydrophyllaceae).

    PubMed

    McCall, Andrew C

    2007-03-01

    Researchers can answer questions about the evolution or maintenance of separate sexes using dioecious plant systems. Because females in these species typically put more resources into reproductive effort than male plants, researchers have hypothesized that females may be less tolerant of the stresses found in marginal habitats. Herbivory can act as a biotic stressor that reduces resources in plants much like a marginal habitat can. Females may be limited by resources, and may thus be less tolerant to herbivory than males. Here, I explore the relationships between florivory, leaf herbivory, and gender in a gynodioecious, annual plant, Nemophila menziesii (Hydrophyllaceae, senso lato). I performed a crossed design experiment examining the main effects and interactions of plant gender, artificial leaf damage, and artificial flower damage on components of female plant fitness. Leaf damage decreased fruit set and females made significantly more fruit than hermaphrodites. However, contrary to theory, I found little evidence for a gender by damage interaction for either type of artificial herbivory. Based on these results, I propose more work exploring the effects of both source and sink damage in dioecious species to help elucidate where and when different sexual morphs are favored by natural selection. PMID:21636414

  15. How environmental conditions affect canopy leaf-level photosynthesis in four deciduous tree species

    SciTech Connect

    Bassow, S.L.; Bazzaz, F.A.

    1998-12-01

    Species composition of temperate forests vary with successional age and seems likely to change in response to significant global climate change. Because photosynthesis rates in co-occurring tree species can differ in their sensitivity to environmental conditions, these changes in species composition are likely to alter the carbon dynamics of temperate forests. To help improve their understanding of such atmosphere-biosphere interactions, the authors explored changes in leaf-level photosynthesis in a 60--70 yr old temperate mixed-deciduous forest in Petersham, Massachusetts (USA). Diurnally and seasonally varying environmental conditions differentially influenced in situ leaf-level photosynthesis rates in the canopies of four mature temperate deciduous tree species: red oak (Quercus rubra), red maple (Acer rubrum), white birch (Betula papyrifera), and yellow birch (Betula alleghaniensis). The authors measured in situ photosynthesis at two heights within the canopies through a diurnal time course on 7 d over two growing seasons. They simultaneously measured a suite of environmental conditions surrounding the leaf at the time of each measurement. The authors used path analysis to examine the influence of environmental factors on in situ photosynthesis in the tree canopies.

  16. Gold, Silver and Bronze Citations.

    ERIC Educational Resources Information Center

    American School & University, 2003

    2003-01-01

    Presents the gold, silver, and bronze winners of a competition, which judged the most outstanding learning environments at educational institutions nationwide. Jurors spent two days reviewing projects, focusing on concepts and ideas that made them exceptional. For each citation, the article offers information on the firm, client, total area, total…

  17. Ancient Chinese Bronzes: Teacher's Packet.

    ERIC Educational Resources Information Center

    Smithsonian Institution, Washington, DC. Arthur M. Sackler Gallery.

    The focus of this teacher's packet is the bronze vessels made for the kings and great families of the early Chinese dynasties between 1700 B.C. and 200 A.D. The materials in the guide are intended for use by teachers and students visiting the exhibition, "The Arts of China," at the Arthur M. Sackler Gallery of the Smithsonian Institution in…

  18. Oral administration of leaf extracts of Momordica charantia affect reproductive hormones of adult female Wistar rats

    PubMed Central

    Adewale, Osonuga Odusoga; Oduyemi, Osonuga Ifabunmi; Ayokunle, Osonuga

    2014-01-01

    Objective To determine the effect of graded doses of aqueous leaf extracts of Momordica charantia on fertility hormones of female albino rats. Methods Twenty adult, healthy, female Wistar rats were divided into four groups: low dose (LD), moderate dose (MD) and high dose (HD) groups which received 12.5 g, 25.0 g, 50.0 g of the leaf extract respectively and control group that was given with water ad libatum. Result Estrogen levels reduced by 6.40 nmol/L, 10.80 nmol/L and 28.00 nmol/L in the LD, MD and HD groups respectively while plasma progesterone of rats in the LD, MD and HD groups reduced by 24.20 nmol/L, 40.8 nmol/L and 59.20 nmol/L respectively. Conclusion Our study has shown that the antifertility effect of Momordica charantia is achieved in a dose dependent manner. Hence, cautious use of such medication should be advocated especially when managing couples for infertility. PMID:25183143

  19. Phragmites australis and Quercus robur leaf extracts affect antioxidative system and photosynthesis of Ceratophyllum demersum.

    PubMed

    Kamara, Sheku; Pflugmacher, Stephan

    2007-06-01

    During senescence, leaves are deposited on aquatic bodies and decay under water releasing chemical substances that might exert physiological stress to aquatic organisms. Leaf litter alone contributes 30% of the total dissolved organic carbon (DOC) in streams. We investigated the impact of leaves extract from Phragmites australis and Quercus robur on the antioxidative system and photosynthetic rate of the aquatic macrophyte Ceratophyllum demersum exposed for 24h. Rate of photosynthetic oxygen release and antioxidant enzyme activity (glutathione S-transferases, glutathione reductases and peroxidases) as well as lipid peroxidation in C. demersum were measured. Significant (P<0.01) elevations of antioxidative enzyme activity in C. demersum which tends to plateau at high DOC concentrations were observed. There was no detectable effect on lipid peroxidation. A significant dose-dependent reduction in photosynthetic oxygen production was measured. PMID:16996134

  20. Neutron Imaging of Archaeological Bronzes

    SciTech Connect

    Ryzewski, Krysta; Herringer, Susan; Bilheux, Hassina Z; Walker, Lakeisha MH; Sheldon, Brian; Voisin, Sophie; Bilheux, Jean-Christophe; Finocchiaro, Vincenzo

    2013-01-01

    This article presents the initial results of 2-D and 3-D neutron imaging of bronze artifacts using the CG-1D prototype beamline at the High Flux Isotope Reactor (HFIR) located at the Oak Ridge National Laboratory (ORNL). Neutron imaging is a non-destructive technique capable of producing unprecedented three-dimensional information on archaeomaterials, including qualitative, quantitative, and visual data on impurities, composition change, voids, and c

  1. Differences in the sensitivity of fungi and bacteria to season and invertebrates affect leaf litter decomposition in a Mediterranean stream.

    PubMed

    Mora-Gómez, Juanita; Elosegi, Arturo; Duarte, Sofia; Cássio, Fernanda; Pascoal, Cláudia; Romaní, Anna M

    2016-08-01

    Microorganisms are key drivers of leaf litter decomposition; however, the mechanisms underlying the dynamics of different microbial groups are poorly understood. We investigated the effects of seasonal variation and invertebrates on fungal and bacterial dynamics, and on leaf litter decomposition. We followed the decomposition of Populus nigra litter in a Mediterranean stream through an annual cycle, using fine and coarse mesh bags. Irrespective of the season, microbial decomposition followed two stages. Initially, bacterial contribution to total microbial biomass was higher compared to later stages, and it was related to disaccharide and lignin degradation; in a later stage, bacteria were less important and were associated with hemicellulose and cellulose degradation, while fungi were related to lignin decomposition. The relevance of microbial groups in decomposition differed among seasons: fungi were more important in spring, whereas in summer, water quality changes seemed to favour bacteria and slowed down lignin and hemicellulose degradation. Invertebrates influenced litter-associated microbial assemblages (especially bacteria), stimulated enzyme efficiencies and reduced fungal biomass. We conclude that bacterial and fungal assemblages play distinctive roles in microbial decomposition and differ in their sensitivity to environmental changes, ultimately affecting litter decomposition, which might be particularly relevant in highly seasonal ecosystems, such as intermittent streams. PMID:27288197

  2. Vertical Chlorophyll Canopy Structure Affects the Remote Sensing Based Predictability of LAI, Chlorophyll and Leaf Nitrogen in Agricultural Fields

    NASA Astrophysics Data System (ADS)

    Boegh, E.; Houborg, R.; Bienkowski, J.; Braban, C. F.; Dalgaard, T.; van Dijk, N.; Dragosits, U.; Holmes, E.; Magliulo, V.; Schelde, K.; Di Tommasi, P.; Vitale, L.; Theobald, M.; Cellier, P.; Sutton, M.

    2012-12-01

    SVIs require field data for empirical model building, the REGFLEC model was applied without calibration. LAI and SPAD meter data were measured in 93 fields representing 10 crop types of the five European landscapes. SPAD meter data were measured at five canopy height levels and converted to CHL and N using laboratory calibration. The data showed strong vertical leaf chlorophyll gradient profiles in 20 % of fields. This affected the predictability of SVIs and REGFLEC. However, selecting only homogeneous canopies with uniform CHL distributions as reference data for statistical evaluation, significant predictions were achieved for all landscapes, by all methods, with the best overall results given by REGFLEC. Predictabilities of SVIs and REGFLEC simulations improved when constrained to single land use categories across the European landscapes, reflecting sensitivity to canopy structures, and predictabilities further improved when constrained to local (10 x 10 km2) landscapes, thereby reflecting sensitivity to local environmental conditions. The Enhanced Vegetation Index-2 tended to be the best method in landscapes with high vegetation densities, REGFLEC worked best in a landscape with large contrasts in vegetation density, and the Simple Ratio worked best in a landscape characterized by low vegetation density.

  3. Oleuropein-Enriched Olive Leaf Extract Affects Calcium Dynamics and Impairs Viability of Malignant Mesothelioma Cells.

    PubMed

    Marchetti, Carla; Clericuzio, Marco; Borghesi, Barbara; Cornara, Laura; Ribulla, Stefania; Gosetti, Fabio; Marengo, Emilio; Burlando, Bruno

    2015-01-01

    Malignant mesothelioma is a poor prognosis cancer in urgent need of alternative therapies. Oleuropein, the major phenolic of olive tree (Olea europaea L.), is believed to have therapeutic potentials for various diseases, including tumors. We obtained an oleuropein-enriched fraction, consisting of 60% w/w oleuropein, from olive leaves, and assessed its effects on intracellular Ca(2+) and cell viability in mesothelioma cells. Effects of the oleuropein-enriched fraction on Ca(2+) dynamics and cell viability were studied in the REN mesothelioma cell line, using fura-2 microspectrofluorimetry and MTT assay, respectively. Fura-2-loaded cells, transiently exposed to the oleuropein-enriched fraction, showed dose-dependent transient elevations of cytosolic Ca(2+) concentration ([Ca(2+)]i). Application of standard oleuropein and hydroxytyrosol, and of the inhibitor of low-voltage T-type Ca(2+) channels NNC-55-0396, suggested that the effect is mainly due to oleuropein acting through its hydroxytyrosol moiety on T-type Ca(2+) channels. The oleuropein-enriched fraction and standard oleuropein displayed a significant antiproliferative effect, as measured on REN cells by MTT cell viability assay, with IC50 of 22 μg/mL oleuropein. Data suggest that our oleuropein-enriched fraction from olive leaf extract could have pharmacological application in malignant mesothelioma anticancer therapy, possibly by targeting T-type Ca(2+) channels and thereby dysregulating intracellular Ca(2+) dynamics. PMID:26693247

  4. Oleuropein-Enriched Olive Leaf Extract Affects Calcium Dynamics and Impairs Viability of Malignant Mesothelioma Cells

    PubMed Central

    Marchetti, Carla; Clericuzio, Marco; Borghesi, Barbara; Cornara, Laura; Ribulla, Stefania; Gosetti, Fabio; Marengo, Emilio; Burlando, Bruno

    2015-01-01

    Malignant mesothelioma is a poor prognosis cancer in urgent need of alternative therapies. Oleuropein, the major phenolic of olive tree (Olea europaea L.), is believed to have therapeutic potentials for various diseases, including tumors. We obtained an oleuropein-enriched fraction, consisting of 60% w/w oleuropein, from olive leaves, and assessed its effects on intracellular Ca2+ and cell viability in mesothelioma cells. Effects of the oleuropein-enriched fraction on Ca2+ dynamics and cell viability were studied in the REN mesothelioma cell line, using fura-2 microspectrofluorimetry and MTT assay, respectively. Fura-2-loaded cells, transiently exposed to the oleuropein-enriched fraction, showed dose-dependent transient elevations of cytosolic Ca2+ concentration ([Ca2+]i). Application of standard oleuropein and hydroxytyrosol, and of the inhibitor of low-voltage T-type Ca2+ channels NNC-55-0396, suggested that the effect is mainly due to oleuropein acting through its hydroxytyrosol moiety on T-type Ca2+ channels. The oleuropein-enriched fraction and standard oleuropein displayed a significant antiproliferative effect, as measured on REN cells by MTT cell viability assay, with IC50 of 22 μg/mL oleuropein. Data suggest that our oleuropein-enriched fraction from olive leaf extract could have pharmacological application in malignant mesothelioma anticancer therapy, possibly by targeting T-type Ca2+ channels and thereby dysregulating intracellular Ca2+ dynamics. PMID:26693247

  5. The bacterial pathogen Xylella fastidiosa affects the leaf ionome of plant hosts during infection.

    PubMed

    De La Fuente, Leonardo; Parker, Jennifer K; Oliver, Jonathan E; Granger, Shea; Brannen, Phillip M; van Santen, Edzard; Cobine, Paul A

    2013-01-01

    Xylella fastidiosa is a plant pathogenic bacterium that lives inside the host xylem vessels, where it forms biofilm believed to be responsible for disrupting the passage of water and nutrients. Here, Nicotiana tabacum was infected with X. fastidiosa, and the spatial and temporal changes in the whole-leaf ionome (i.e. the mineral and trace element composition) were measured as the host plant transitioned from healthy to diseased physiological status. The elemental composition of leaves was used as an indicator of the physiological changes in the host at a specific time and relative position during plant development. Bacterial infection was found to cause significant increases in concentrations of calcium prior to the appearance of symptoms and decreases in concentrations of phosphorous after symptoms appeared. Field-collected leaves from multiple varieties of grape, blueberry, and pecan plants grown in different locations over a four-year period in the Southeastern US showed the same alterations in Ca and P. This descriptive ionomics approach characterizes the existence of a mineral element-based response to X. fastidiosa using a model system suitable for further manipulation to uncover additional details of the role of mineral elements during plant-pathogen interactions. This is the first report on the dynamics of changes in the ionome of the host plant throughout the process of infection by a pathogen. PMID:23667547

  6. A mutation, tl2, in pea (Pisum sativum L.) affects leaf development only in the heterozygous state.

    PubMed

    Berdnikov, V A; Gorel, F L

    2005-04-01

    After gamma irradiation of pea seeds, a mutation designated as tendril-less2 (tl2) was induced. In the heterozygous state, it transforms tendrils into very narrow leaflets that resemble the heterozygote phenotype of the classic tl mutation. The tendrils of the double heterozygote tl2/+, tl/+ are converted into oval leaflets. Unlike tl, the novel mutation in the homozygous state does not affect tendrils. The leaf phenotype of homozygotes tl2/tl2 and Tl2/Tl2 do not differ in the tl/+ background. However, the anthocyanin pigmentation is strongly suppressed in petals of tl2/tl2 plants. Some hypotheses to explain the unusual phenotypic manifestation of tl2 are suggested. PMID:15714325

  7. Heat-induced electrical signals affect cytoplasmic and apoplastic pH as well as photosynthesis during propagation through the maize leaf.

    PubMed

    Grams, Thorsten E E; Lautner, Silke; Felle, Hubert H; Matyssek, Rainer; Fromm, Jörg

    2009-04-01

    Combining measurements of electric potential and pH with such of chlorophyll fluorescence and leaf gas exchange showed heat stimulation to evoke an electrical signal (propagation speed: 3-5 mm s(-1)) that travelled through the leaf while reducing the net CO(2) uptake rate and the photochemical quantum yield of both photosystems (PS). Two-dimensional imaging analysis of the chlorophyll fluorescence signal of PS II revealed that the yield reduction spread basipetally via the veins through the leaf at a speed of 1.6 +/- 0.3 mm s(-1) while the propagation speed in the intervein region was c. 50 times slower. Propagation of the signal through the veins was confirmed because PS I, which is present in the bundle sheath cells around the leaf vessels, was affected first. Hence, spreading of the signal along the veins represents a path with higher travelling speed than within the intervein region of the leaf lamina. Upon the electrical signal, cytoplasmic pH decreased transiently from 7.0 to 6.4, while apoplastic pH increased transiently from 4.5 to 5.2. Moreover, photochemical quantum yield of isolated chloroplasts was strongly affected by pH changes in the surrounding medium, indicating a putative direct influence of electrical signalling via changes of cytosolic pH on leaf photosynthesis. PMID:19054346

  8. Tree Species Composition and Harvest Intensity Affect Herbivore Density and Leaf Damage on Beech, Fagus sylvatica, in Different Landscape Contexts.

    PubMed

    Mangels, Jule; Blüthgen, Nico; Frank, Kevin; Grassein, Fabrice; Hilpert, Andrea; Mody, Karsten

    2015-01-01

    Most forests are exposed to anthropogenic management activities that affect tree species composition and natural ecosystem processes. Changes in ecosystem processes such as herbivory depend on management intensity, and on regional environmental conditions and species pools. Whereas influences of specific forest management measures have already been addressed for different herbivore taxa on a local scale, studies considering effects of different aspects of forest management across different regions are rare. We assessed the influence of tree species composition and intensity of harvesting activities on arthropod herbivores and herbivore-related damage to beech trees, Fagus sylvatica, in 48 forest plots in three regions of Germany. We found that herbivore abundance and damage to beech trees differed between regions and that - despite the regional differences - density of tree-associated arthropod taxa and herbivore damage were consistently affected by tree species composition and harvest intensity. Specifically, overall herbivore damage to beech trees increased with increasing dominance of beech trees - suggesting the action of associational resistance processes - and decreased with harvest intensity. The density of leaf chewers and mines was positively related to leaf damage, and several arthropod groups responded to beech dominance and harvest intensity. The distribution of damage patterns was consistent with a vertical shift of herbivores to higher crown layers during the season and with higher beech dominance. By linking quantitative data on arthropod herbivore abundance and herbivory with tree species composition and harvesting activity in a wide variety of beech forests, our study helps to better understand the influence of forest management on interactions between a naturally dominant deciduous forest tree and arthropod herbivores. PMID:25938417

  9. Tree Species Composition and Harvest Intensity Affect Herbivore Density and Leaf Damage on Beech, Fagus sylvatica, in Different Landscape Contexts

    PubMed Central

    Mangels, Jule; Blüthgen, Nico; Frank, Kevin; Grassein, Fabrice; Hilpert, Andrea; Mody, Karsten

    2015-01-01

    Most forests are exposed to anthropogenic management activities that affect tree species composition and natural ecosystem processes. Changes in ecosystem processes such as herbivory depend on management intensity, and on regional environmental conditions and species pools. Whereas influences of specific forest management measures have already been addressed for different herbivore taxa on a local scale, studies considering effects of different aspects of forest management across different regions are rare. We assessed the influence of tree species composition and intensity of harvesting activities on arthropod herbivores and herbivore-related damage to beech trees, Fagus sylvatica, in 48 forest plots in three regions of Germany. We found that herbivore abundance and damage to beech trees differed between regions and that – despite the regional differences - density of tree-associated arthropod taxa and herbivore damage were consistently affected by tree species composition and harvest intensity. Specifically, overall herbivore damage to beech trees increased with increasing dominance of beech trees – suggesting the action of associational resistance processes – and decreased with harvest intensity. The density of leaf chewers and mines was positively related to leaf damage, and several arthropod groups responded to beech dominance and harvest intensity. The distribution of damage patterns was consistent with a vertical shift of herbivores to higher crown layers during the season and with higher beech dominance. By linking quantitative data on arthropod herbivore abundance and herbivory with tree species composition and harvesting activity in a wide variety of beech forests, our study helps to better understand the influence of forest management on interactions between a naturally dominant deciduous forest tree and arthropod herbivores. PMID:25938417

  10. TCP14 and TCP15 affect internode length and leaf shape in Arabidopsis

    PubMed Central

    Kieffer, Martin; Master, Vera; Waites, Richard; Davies, Brendan

    2011-01-01

    TCP transcription factors constitute a small family of plant-specific bHLH-containing, DNA-binding proteins that have been implicated in the control of cell proliferation in plants. Despite the significant role that is likely to be played by genes that control cell division in the elaboration of plant architecture, functional analysis of this family by forward and reverse genetics has been hampered by genetic redundancy. Here we show that mutants in two related class I TCP genes display a range of growth-related phenotypes, consistent with their dynamic expression patterns; these phenotypes are enhanced in the double mutant. Together, the two genes influence plant stature by promoting cell division in young internodes. Reporter gene analysis and use of SRDX fusions suggested that TCP14 and TCP15 modulate cell proliferation in the developing leaf blade and specific floral tissues; a role that was not apparent in our phenotypic analysis of single or double mutants. However, when the relevant mutants were subjected to computer-aided morphological analysis of the leaves, the consequences of loss of either or both genes became obvious. The effects on cell proliferation of perturbing the function of TCP14 and TCP15 vary with tissue, as has been suggested for other TCP factors. These findings indicate that the precise elaboration of plant form is dependent on the cumulative influence of many TCP factors acting in a context-dependent fashion. The study highlights the need for advanced methods of phenotypic analysis in order to characterize phenotypes and to construct a dynamic model for TCP gene function. PMID:21668538

  11. 21 CFR 73.2646 - Bronze powder.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2646 Bronze powder. (a) Identity and specifications. The....1646 (a)(1) and (b). (b) Uses and restrictions. Bronze powder may be safely used in coloring cosmetics generally, including cosmetics intended for use in the area of the eye, in amounts consistent with...

  12. 21 CFR 73.2646 - Bronze powder.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2646 Bronze powder. (a) Identity and specifications. The....1646 (a)(1) and (b). (b) Uses and restrictions. Bronze powder may be safely used in coloring cosmetics generally, including cosmetics intended for use in the area of the eye, in amounts consistent with...

  13. 21 CFR 73.2646 - Bronze powder.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2646 Bronze powder. (a) Identity and specifications. The....1646 (a)(1) and (b). (b) Uses and restrictions. Bronze powder may be safely used in coloring cosmetics generally, including cosmetics intended for use in the area of the eye, in amounts consistent with...

  14. Satellite based remote sensing technique as a tool for real time monitoring of leaf retention in natural rubber plantations affected by abnormal leaf fall disease

    NASA Astrophysics Data System (ADS)

    Pradeep, B.; Meti, S.; James, J.

    2014-11-01

    Most parts of the traditional natural rubber growing regions of India, extending from Kanyakumari district of Tamil Nadu in the South to Kasaragod district of Kerala in the North received excess and prolonged rains during 2013. This led to severe incidence of Abnormal Leaf Fall (ALF) disease caused by the fungus, Phytophthora sp. The present study demonstrated the first time use of satellite remote sensing technique to monitor ALF disease by estimating Leaf Area Index (LAI) in natural rubber holdings in near real time. Leaf retention was monitored in between April and December 2012 and 2013 by estimating LAI using MODIS 15A2 product covering rubber holdings spread across all districts in the traditional rubber growing region of the country that was mapped using Resourcesat LISS III 2012 and 2013 data. It was found that as the monsoon advanced, LAI decreased substantially in both years, but the reduction was much more substantial and prolonged in many districts during 2013 than 2012 reflecting increased leaf fall due to ALF disease in 2013. The decline was more pronounced in central and northern Kerala than in the South. Kanyakumari district of Tamil Nadu is generally known to be free from ALF disease, but there was considerable leaf loss due to ALF in June 2012 and June and July 2013 even as the monsoon was unusually severe in 2013. Weighted mean LAI during for the entire period of April to December was estimated as a weighted average of LAI and per cent of total area under rubber in each district in the study area for the two years. This was markedly less in 2013 than 2012. The implications of poor leaf retention for biomass production (net primary productivity), carbon sequestration and rubber yield are discussed.

  15. Edge type affects leaf-level water relations and estimated transpiration of Eucalyptus arenacea.

    PubMed

    Wright, Thomas E; Tausz, Michael; Kasel, Sabine; Volkova, Liubov; Merchant, Andrew; Bennett, Lauren T

    2012-03-01

    While edge effects on tree water relations are well described for closed forests, they remain under-examined in more open forest types. Similarly, there has been minimal evaluation of the effects of contrasting land uses on the water relations of open forest types in highly fragmented landscapes. We examined edge effects on the water relations and gas exchange of a dominant tree (Eucalyptus arenacea Marginson & Ladiges) in an open forest type (temperate woodland) of south-eastern Australia. Edge effects in replicate woodlands adjoined by cleared agricultural land (pasture edges) were compared with those adjoined by 7- to 9-year-old eucalypt plantation with a 25m fire break (plantation edges). Consistent with studies in closed forest types, edge effects were pronounced at pasture edges where photosynthesis, transpiration and stomatal conductance were greater for edge trees than interior trees (75m into woodlands), and were related to greater light availability and significantly higher branch water potentials at woodland edges than interiors. Nonetheless, gas exchange values were only ∼50% greater for edge than interior trees, compared with ∼200% previously found in closed forest types. In contrast to woodlands adjoined by pasture, gas exchange in winter was significantly lower for edge than interior trees in woodlands adjoined by plantations, consistent with shading and buffering effects of plantations on edge microclimate. Plantation edge effects were less pronounced in summer, although higher water use efficiency of edge than interior woodland trees indicated possible competition for water between plantation trees and woodland edge trees in the drier months (an effect that might have been more pronounced were there no firebreak between the two land uses). Scaling up of leaf-level water relations to stand transpiration using a Jarvis-type phenomenological model indicated similar differences between edge types. That is, transpiration was greater at pasture than

  16. Solar UV-B radiation affects leaf quality and insect herbivory in the southern beech tree Nothofagus antarctica.

    PubMed

    Rousseaux, M Cecilia; Julkunen-Tiitto, Riitta; Searles, Peter S; Scopel, Ana L; Aphalo, Pedro J; Ballaré, Carlos L

    2004-03-01

    We examined the effects of solar ultraviolet-B (UV-B) radiation on plant-insect interactions in Tierra del Fuego (55 degrees S), Argentina, an area strongly affected by ozone depletion because of its proximity to Antarctica. Solar UV-B under Nothofagus antarctica branches was manipulated using a polyester plastic film to attenuate UV-B (uvb-) and an Aclar film to provide near-ambient UV-B (uvb+). The plastic films were placed on both north-facing (i.e., high solar radiation in the Southern Hemisphere) and south-facing branches. Insects consumed 40% less leaf area from north- than from south-facing branches, and at least 30% less area from uvb+ branches than from uvb- branches. The reduced herbivory on leaves from uvb+ branches occurred for both branch orientations. Leaf mass per area increased and relative water content decreased on north- versus south-facing branches, while no differences were apparent between the UV-B treatments. Solar UV-B did lead to lower gallic acid concentration and higher flavonoid aglycone concentration in uvb+ leaves relative to uvb- leaves. Both the flavonoid aglycone and quercetin-3-arabinopyranoside were higher on north-facing branches. In laboratory preference experiments, larvae of the dominant insect in the natural community, Geometridae "Brown" (Lepidoptera), consumed less area from field-grown uvb+ leaves than from uvb- leaves in 1996-97, but not in 1997-98. Correlation analyses suggested that the reduction in insect herbivory in the field under solar UV-B may be mediated in part by the UV-B effects on gallic acid and flavonoid aglycone. PMID:14740287

  17. Laser fusing of HVOF thermal sprayed alloy 625 on nickel-aluminum bronze

    SciTech Connect

    Brenna, R.T.; Pugh, J.L.; Denney, P.E.

    1994-12-31

    A preliminary study has been conducted to determine the feasibility of laser fusing alloy 625 onto nickel-aluminum-bronze base metal. Laser fusing was performed by melting a pre-coated surface of alloy 625 that had been applied by the high velocity oxyfuel (HVOF) thermal spray process. The laser fusing was successful in producing a metallurigical bond between alloy 625 and the substrate. Minor modification to the heat-affected zone of the base metal was observed by microhardness measurements, and defect-free interfaces were produced between alloy 625 and nickel-aluminum-bronze by the process. The laser is a high energy density source that can be used for precise thermal processing of materials including surface modification. Laser fusing is the full or partial melting of a coating material that has been previously applied in some fashion to the substrate. Thermal spray coating of nickel-aluminum-bronze material with alloy 625 was conducted at the David Taylor Research Center. Nickel-aluminum-bronze specimens 2 x 3-in. by 1/2-in. thick were coated with alloy 25 utilizing the HVOF equipment. Coating thicknesses of approximately 0.014-in. (0.3 mm) were produced for subsequent laser fusing experiments. A preliminary study has been conducted to determine the feasibility of laser fusing a HVOF thermal sprayed alloy 625 coating onto nickel-aluminum-bronze base metal. Conclusions of this investigation were as follows: (1) Laser fusing was successful in producing a metallurgical bond between HVOF thermal sprayed alloy 625 and the nickel-aluminum-bronze. (2) Only minor microstructural modification to the heat-affected zone of the base metal ws observed by microhardness measurements. (3) Defect-free interfaces were produced between thermal sprayed alloy 625 and nickel-aluminum-bronze by laser fusing.

  18. Natural enemies of Atta vollenweideri (Hymenoptera: Formicidae) leaf-cutter ants negatively affected by synthetic pesticides, chlorpyrifos and fipronil.

    PubMed

    Guillade, Andrea C; Folgarait, Patricia J

    2014-02-01

    In southern South America, Ada vollenweideri Forel (Hymenoptera: Formicidae) is a significant pest of several crops and forestry, also considered to reduce the carrying capacity of pastures. The most usual control method used in Latin America is the application of synthetic pesticides, mainly chlorpyrifos and fipronil. However, no studies have assessed the effects of these agrochemicals on natural enemies of ants. We aimed to evaluate the efficiency of these pesticides on leaf-cutter ants' control and to test their effect on phorid fly parasitoids. Chlorpyrifos failed to exert complete control over ant colonies in the field and was gravely detrimental to specific parasitoids, reducing their percentage of parasitism, pupal survivorship, and adult longevity. Fipronil, however, exerted complete control over the treated colonies. Laboratory tests using both pesticides, either on ants from foraging trails or on pupariae, showed that chlorpyrifos and fipronil decreased larval and pupal survivorship, as well as adult longevity of parasitoids, in comparison to controls. In conclusion, these pesticides will likely affect parasitoids with regard to their reproductive capacity, leading to the decreased levels of natural parasitism observed in the field after treatments. We discuss why neither pesticide should be taken into account for integrated pest management programs. PMID:24665691

  19. A high proportion of blue light increases the photosynthesis capacity and leaf formation rate of Rosa × hybrida but does not affect time to flower opening.

    PubMed

    Terfa, Meseret Tesema; Solhaug, Knut Asbjørn; Gislerød, Hans Ragnar; Olsen, Jorunn Elisabeth; Torre, Sissel

    2013-05-01

    Alterations in light quality affect plant morphogenesis and photosynthetic responses but the effects vary significantly between species. Roses exhibit an irradiance-dependent flowering control but knowledge on light quality responses is scarce. In this study we analyzed, the responses in morphology, photosynthesis and flowering of Rosa × hybrida to different blue (B) light proportions provided by light-emitting diodes (LED, high B 20%) and high pressure sodium (HPS, low B 5%) lamps. There was a strong morphological and growth effect of the light sources but no significant difference in total dry matter production and flowering. HPS-grown plants had significantly higher leaf area and plant height, yet a higher dry weight proportion was allocated to leaves than stems under LED. LED plants showed 20% higher photosynthetic capacity (Amax ) and higher levels of soluble carbohydrates. The increase in Amax correlated with an increase in leaf mass per unit leaf area, higher stomata conductance and CO2 exchange, total chlorophyll (Chl) content per area and Chl a/b ratio. LED-grown leaves also displayed a more sun-type leaf anatomy with more and longer palisade cells and a higher stomata frequency. Although floral initiation occurred at a higher leaf number in LED, the time to open flowers was the same under both light conditions. Thereby the study shows that a higher portion of B light is efficient in increasing photosynthesis performance per unit leaf area, enhancing growth and morphological changes in roses but does not affect the total Dry Matter (DM) production or time to open flower. PMID:23020549

  20. Population genomics of Bronze Age Eurasia.

    PubMed

    Allentoft, Morten E; Sikora, Martin; Sjögren, Karl-Göran; Rasmussen, Simon; Rasmussen, Morten; Stenderup, Jesper; Damgaard, Peter B; Schroeder, Hannes; Ahlström, Torbjörn; Vinner, Lasse; Malaspinas, Anna-Sapfo; Margaryan, Ashot; Higham, Tom; Chivall, David; Lynnerup, Niels; Harvig, Lise; Baron, Justyna; Della Casa, Philippe; Dąbrowski, Paweł; Duffy, Paul R; Ebel, Alexander V; Epimakhov, Andrey; Frei, Karin; Furmanek, Mirosław; Gralak, Tomasz; Gromov, Andrey; Gronkiewicz, Stanisław; Grupe, Gisela; Hajdu, Tamás; Jarysz, Radosław; Khartanovich, Valeri; Khokhlov, Alexandr; Kiss, Viktória; Kolář, Jan; Kriiska, Aivar; Lasak, Irena; Longhi, Cristina; McGlynn, George; Merkevicius, Algimantas; Merkyte, Inga; Metspalu, Mait; Mkrtchyan, Ruzan; Moiseyev, Vyacheslav; Paja, László; Pálfi, György; Pokutta, Dalia; Pospieszny, Łukasz; Price, T Douglas; Saag, Lehti; Sablin, Mikhail; Shishlina, Natalia; Smrčka, Václav; Soenov, Vasilii I; Szeverényi, Vajk; Tóth, Gusztáv; Trifanova, Synaru V; Varul, Liivi; Vicze, Magdolna; Yepiskoposyan, Levon; Zhitenev, Vladislav; Orlando, Ludovic; Sicheritz-Pontén, Thomas; Brunak, Søren; Nielsen, Rasmus; Kristiansen, Kristian; Willerslev, Eske

    2015-06-11

    The Bronze Age of Eurasia (around 3000-1000 BC) was a period of major cultural changes. However, there is debate about whether these changes resulted from the circulation of ideas or from human migrations, potentially also facilitating the spread of languages and certain phenotypic traits. We investigated this by using new, improved methods to sequence low-coverage genomes from 101 ancient humans from across Eurasia. We show that the Bronze Age was a highly dynamic period involving large-scale population migrations and replacements, responsible for shaping major parts of present-day demographic structure in both Europe and Asia. Our findings are consistent with the hypothesized spread of Indo-European languages during the Early Bronze Age. We also demonstrate that light skin pigmentation in Europeans was already present at high frequency in the Bronze Age, but not lactose tolerance, indicating a more recent onset of positive selection on lactose tolerance than previously thought. PMID:26062507

  1. Molecular genetics of growth and development in Populus (Salicaceae). V. Mapping quantitative trait loci affecting leaf variation

    SciTech Connect

    Wu, R.; Bradshaw, H.D. Jr.; Stettler, R.F.

    1997-02-01

    The genetic variation of leaf morphology and development was studied in the 2-yr-old replicated plantation of an interspecific hybrid pedigree of Populus trichocarpa T. & G. and P. deltoides Marsh. via both molecular and quantitative genetic methods. Leaf traits chosen showed pronounced differences between the original parents, including leaf size, shape, orientation, color, structure, petiole size, and petiole cross section. In the F{sub 2} generation, leaf traits were all significantly different among genotypes, but with significant effects due to genotype X crown-position interaction. Variation in leaf pigmentation, petiole length, and petiole length proportion appeared to be under the control of few quantitative trait loci (QTLs). More QTLs were associated with single leaf area, leaf shape, lamina angle, abaxial color, and petiole flatness, and in these traits the number of QTLs varied among crown positions. In general the estimates of QTL numbers from Wright`s biometric method were close to those derived from molecular markers. For those traits with few underlying QTLs, a single marker interval could explain from 30-60% of the observed phenotypic variance. For multigenic traits, certain markers contributed more substantially to the observed variation than others. Genetic cluster analysis showed developmentally related traits to be more strongly associated with each other than with unrelated traits. This finding was also supported by the QTL mapping. For example, the same chromosomal segment of linkage group L seemed to account for 20% of the phenotypic variation of all dimension-related traits, leaf size, petiole length, and midrib angle. In both traits, the P. deltoides alleles had positive effects and were dominant to the P. trichocarpa alleles. Similar relationships were also found for lamina angle, abaxial greenness, and petiole flatness. 72 refs., 3 figs., 2 tabs.

  2. Antiphase Light and Temperature Cycles Affect PHYTOCHROME B-Controlled Ethylene Sensitivity and Biosynthesis, Limiting Leaf Movement and Growth of Arabidopsis1[C][W

    PubMed Central

    Bours, Ralph; van Zanten, Martijn; Pierik, Ronald; Bouwmeester, Harro; van der Krol, Alexander

    2013-01-01

    In the natural environment, days are generally warmer than the night, resulting in a positive day/night temperature difference (+DIF). Plants have adapted to these conditions, and when exposed to antiphase light and temperature cycles (cold photoperiod/warm night [−DIF]), most species exhibit reduced elongation growth. To study the physiological mechanism of how light and temperature cycles affect plant growth, we used infrared imaging to dissect growth dynamics under +DIF and −DIF in the model plant Arabidopsis (Arabidopsis thaliana). We found that −DIF altered leaf growth patterns, decreasing the amplitude and delaying the phase of leaf movement. Ethylene application restored leaf growth in −DIF conditions, and constitutive ethylene signaling mutants maintain robust leaf movement amplitudes under −DIF, indicating that ethylene signaling becomes limiting under these conditions. In response to −DIF, the phase of ethylene emission advanced 2 h, but total ethylene emission was not reduced. However, expression analysis on members of the 1-aminocyclopropane-1-carboxylic acid (ACC) synthase ethylene biosynthesis gene family showed that ACS2 activity is specifically suppressed in the petiole region under −DIF conditions. Indeed, petioles of plants under −DIF had reduced ACC content, and application of ACC to the petiole restored leaf growth patterns. Moreover, acs2 mutants displayed reduced leaf movement under +DIF, similar to wild-type plants under −DIF. In addition, we demonstrate that the photoreceptor PHYTOCHROME B restricts ethylene biosynthesis and constrains the −DIF-induced phase shift in rhythmic growth. Our findings provide a mechanistic insight into how fluctuating temperature cycles regulate plant growth. PMID:23979970

  3. Factors affecting the abundance of leaf-litter arthropods in unburned and thrice-burned seasonally-dry Amazonian forests.

    PubMed

    Silveira, Juliana M; Barlow, Jos; Louzada, Julio; Moutinho, Paulo

    2010-01-01

    Fire is frequently used as a land management tool for cattle ranching and annual crops in the Amazon. However, these maintenance fires often escape into surrounding forests, with potentially severe impacts for forest biodiversity. We examined the effect of experimental fires on leaf-litter arthropod abundance in a seasonally-dry forest in the Brazilian Amazon. The study plots (50 ha each) included a thrice-burned forest and an unburned control forest. Pitfall-trap samples were collected at 160 randomly selected points in both plots, with sampling stratified across four intra-annual replicates across the dry and wet seasons, corresponding to 6, 8, 10 and 12 months after the most recent fire. Arthropods were identified to the level of order (separating Formicidae). In order to better understand the processes that determine arthropod abundance in thrice-burned forests, we measured canopy openness, understory density and litter depth. All arthropod taxa were significantly affected by fire and season. In addition, the interactions between burn treatment and season were highly significant for all taxa but Isoptera. The burned plot was characterized by a more open canopy, lower understory density and shallower litter depth. Hierarchical partitioning revealed that canopy openness was the most important factor explaining arthropod order abundances in the thrice-burned plot, whereas all three environmental variables were significant in the unburned control plot. These results reveal the marked impact of recurrent wildfires and seasonality on litter arthropods in this transitional forest, and demonstrate the overwhelming importance of canopy-openness in driving post-fire arthropod abundance. PMID:20877720

  4. Factors Affecting the Abundance of Leaf-Litter Arthropods in Unburned and Thrice-Burned Seasonally-Dry Amazonian Forests

    PubMed Central

    Silveira, Juliana M.; Barlow, Jos; Louzada, Julio; Moutinho, Paulo

    2010-01-01

    Fire is frequently used as a land management tool for cattle ranching and annual crops in the Amazon. However, these maintenance fires often escape into surrounding forests, with potentially severe impacts for forest biodiversity. We examined the effect of experimental fires on leaf-litter arthropod abundance in a seasonally-dry forest in the Brazilian Amazon. The study plots (50 ha each) included a thrice-burned forest and an unburned control forest. Pitfall-trap samples were collected at 160 randomly selected points in both plots, with sampling stratified across four intra-annual replicates across the dry and wet seasons, corresponding to 6, 8, 10 and 12 months after the most recent fire. Arthropods were identified to the level of order (separating Formicidae). In order to better understand the processes that determine arthropod abundance in thrice-burned forests, we measured canopy openness, understory density and litter depth. All arthropod taxa were significantly affected by fire and season. In addition, the interactions between burn treatment and season were highly significant for all taxa but Isoptera. The burned plot was characterized by a more open canopy, lower understory density and shallower litter depth. Hierarchical partitioning revealed that canopy openness was the most important factor explaining arthropod order abundances in the thrice-burned plot, whereas all three environmental variables were significant in the unburned control plot. These results reveal the marked impact of recurrent wildfires and seasonality on litter arthropods in this transitional forest, and demonstrate the overwhelming importance of canopy-openness in driving post-fire arthropod abundance. PMID:20877720

  5. Standard methods for chemical analysis of special brasses and bronzes

    SciTech Connect

    Not Available

    1980-01-01

    These methods cover procedures for the chemical analysis of the commercial alloys known as copper-base alloy ingots for sand castings, forging rods, bars, and shapes; aluminum brass; manganese bronze; phosphor bronze; copper-silicon alloys; and similar alloys.

  6. BRASS FOUNDRY MACHINE ROOM USED TO MACHINE CAST BRONZE PIECES ...

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

    BRASS FOUNDRY MACHINE ROOM USED TO MACHINE CAST BRONZE PIECES FOR VALVES AND PREPARE BRONZE VALVE BODIES FOR ASSEMBLY. - Stockham Pipe & Fittings Company, Brass Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  7. Magnitude and Timing of Leaf Damage Affect Seed Production in a Natural Population of Arabidopsis thaliana (Brassicaceae)

    PubMed Central

    Akiyama, Reiko; Ågren, Jon

    2012-01-01

    Background The effect of herbivory on plant fitness varies widely. Understanding the causes of this variation is of considerable interest because of its implications for plant population dynamics and trait evolution. We experimentally defoliated the annual herb Arabidopsis thaliana in a natural population in Sweden to test the hypotheses that (a) plant fitness decreases with increasing damage, (b) tolerance to defoliation is lower before flowering than during flowering, and (c) defoliation before flowering reduces number of seeds more strongly than defoliation during flowering, but the opposite is true for effects on seed size. Methodology/Principal Findings In a first experiment, between 0 and 75% of the leaf area was removed in May from plants that flowered or were about to start flowering. In a second experiment, 0, 25%, or 50% of the leaf area was removed from plants on one of two occasions, in mid April when plants were either in the vegetative rosette or bolting stage, or in mid May when plants were flowering. In the first experiment, seed production was negatively related to leaf area removed, and at the highest damage level, also mean seed size was reduced. In the second experiment, removal of 50% of the leaf area reduced seed production by 60% among plants defoliated early in the season at the vegetative rosettes, and by 22% among plants defoliated early in the season at the bolting stage, but did not reduce seed output of plants defoliated one month later. No seasonal shift in the effect of defoliation on seed size was detected. Conclusions/Significance The results show that leaf damage may reduce the fitness of A. thaliana, and suggest that in this population leaf herbivores feeding on plants before flowering should exert stronger selection on defence traits than those feeding on plants during flowering, given similar damage levels. PMID:22276140

  8. EPIDEMIOLOGY OF ALMOND LEAF SCORCH DISEASE IN THE SAN JOAQUIN VALLEY OF CALIFORNIA: FACTORS AFFECTING PATHOGEN DISTRIBUTION AND MOVEMENT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Almond leaf scorch disease (ALSD) has recently reemerged as a serious threat to almond production areas throughout California’s San Joaquin Valley. This disease, which is caused by the xylem-limited bacterium Xylella fastidiousa, is vectored by xylophagous insects including sharpshooter leafhoppers ...

  9. RNAi-mediated downregulation of poplar plasma membrane intrinsic proteins (PIPs) changes plasma membrane proteome composition and affects leaf physiology.

    PubMed

    Bi, Zhen; Merl-Pham, Juliane; Uehlein, Norbert; Zimmer, Ina; Mühlhans, Stefanie; Aichler, Michaela; Walch, Axel Karl; Kaldenhoff, Ralf; Palme, Klaus; Schnitzler, Jörg-Peter; Block, Katja

    2015-10-14

    Plasma membrane intrinsic proteins (PIPs) are one subfamily of aquaporins that mediate the transmembrane transport of water. To reveal their function in poplar, we generated transgenic poplar plants in which the translation of PIP genes was downregulated by RNA interference investigated these plants with a comprehensive leaf plasma membrane proteome and physiome analysis. First, inhibition of PIP synthesis strongly altered the leaf plasma membrane protein composition. Strikingly, several signaling components and transporters involved in the regulation of stomatal movement were differentially regulated in transgenic poplars. Furthermore, hormonal crosstalk related to abscisic acid, auxin and brassinosteroids was altered, in addition to cell wall biosynthesis/cutinization, the organization of cellular structures and membrane trafficking. A physiological analysis confirmed the proteomic results. The leaves had wider opened stomata and higher net CO2 assimilation and transpiration rates as well as greater mesophyll conductance for CO2 (gm) and leaf hydraulic conductance (Kleaf). Based on these results, we conclude that PIP proteins not only play essential roles in whole leaf water and CO2 flux but have important roles in the regulation of stomatal movement. PMID:26248320

  10. Upper limit for magnetoresistance in silicon bronze and phosphor bronze wire

    NASA Technical Reports Server (NTRS)

    Feldman, R.; Talley, L.; Rojeski, M.; Vold, T.; Woollam, J. A.

    1977-01-01

    The electrical resistivity of silicon bronze and phosphor bronze was measured in magnetic fields from 0 to 14 T and at temperatures between 2 and 300 K. At any fixed temperature, the change in resistivity to 14 T was less than a few parts in 100,000. Thus, these bronzes are excellent for use in high magnetic fields where constant resistance is required. Welding leads to the sample was found to be superior to soldering. The soldered contacts were subject to spurious resistivity changes that resulted from superconducting transitions in the solder.

  11. Crystal chemistry of the natural vanadium bronzes

    USGS Publications Warehouse

    Evans, H.T., Jr.; Hughes, J.M.

    1990-01-01

    The crystal chemistry of the natural vanadium bronze minerals is reviewed on the basis of published information and new studies (mainly by X-ray powder-diffraction methods) using type material wherever possible. The known V bronze minerals are divided into three categories: 1) the hewettite group, 2) the straczekite group, 3) other structure types including navajoite, schubnelite, fervanite, shcherbinaite, bannermanite, and melanovanadite. All known structures associated with the fibrous V bronzes (fiber spacing 3.6 A??) can be considered as various lateral linkages (into sheets or networks) of only two types of polyvanadate chains: 1) a divanadate chain (V2O6)n consisting of alternating square pyramids, and 2) a tetravanadate chain (V4O12)n consisting of four highly condensed single octahedral chains. -from Authors

  12. Scrotal asymmetry, varicocoele and the Riace Bronzes.

    PubMed

    Bonafini, B; Pozzilli, P

    2012-04-01

    In 1972, a pair of remarkably attractive Greek statues, later named Riace Bronzes, were found along the Mediterranean coast in the province of Reggio Calabria, Italy. We analyse the Riace Bronzes in the context of previous research on scrotal asymmetry in Greek statues. By examining their testis, one can define a more exact time of their dating by placing them beside previous observations of scrotal asymmetry, and possibly by taking a pathological condition, varicocoele, as an influencing factor in determining the appearance of the testis. In statue A of the Riace Bronzes, the left testicle is remarkably lower compared with the right one; it also appears as it looks when under physical examination varicocoele is suspected. Being located on the left testicle (as in 90% of cases) and by sight, we feel sufficiently confident to affirm that varicocoele might be diagnosed. PMID:22288773

  13. Clay Corner: Recreating Chinese Bronze Vessels.

    ERIC Educational Resources Information Center

    Gamble, Harriet

    1998-01-01

    Presents a lesson where students make faux Chinese bronze vessels through slab or coil clay construction after they learn about the history, function, and design of these vessels. Utilizes a variety of glaze finishes in order to give the vessels an aged look. Gives detailed guidelines for creating the vessels. (CMK)

  14. Viroid-like RNAs from cherry trees affected by leaf scorch disease: further data supporting their association with mycoviral double-stranded RNAs.

    PubMed

    Minoia, S; Navarro, B; Covelli, L; Barone, M; García-Becedas, M T; Ragozzino, A; Alioto, D; Flores, R; Di Serio, F

    2014-03-01

    Cherry trees from Spain affected by cherry leaf scorch (CLS), a fungal disease proposed to be caused by Apiognomonia erythrostoma, show symptoms (translucent-chlorotic leaf spots evolving into rusty areas) very similar to those of cherry chlorotic rusty spot disease (CCRS) and Amasya cherry disease, reported in Italy and Turkey, respectively. The three maladies are closely associated with 10-12 double-stranded viral RNAs, and CCRS is additionally associated with two cherry small circular RNAs (cscRNA1 and cscRNA2). Here, we report that a small viroid-like RNA similar to the CCRS-associated cscRNA1 is also present in CLS-affected trees, thus extending the link between the two diseases. Both CLS and CCRS cscRNA1 elements have common features, including sequence identity (88%), a predicted quasi rod-like conformation with short bifurcations at both termini, and the presence of hammerhead ribozymes in the strands of both polarities. However, cscRNA2, apparently derived from cscRNA1 by deletion of a short hairpin, was not detected in CLS-affected material. Although the biological nature of cscRNAs is unknown, the identification of at least cscRNA1 in different cherry cultivars and in two distinct geographic areas (Spain and Italy), always in close association with the same mycoviral dsRNAs, supports that these viroid-like RNAs could be satellite RNAs. PMID:24077656

  15. Viroid-like RNAs from cherry trees affected by leaf scorch disease: further data supporting their association with mycoviral double-stranded RNAs.

    PubMed

    Minoia, S; Navarro, B; Covelli, L; Barone, M; García-Becedas, M T; Ragozzino, A; Alioto, D; Flores, R; Di Serio, F

    2014-03-01

    Cherry trees from Spain affected by cherry leaf scorch (CLS), a fungal disease proposed to be caused by Apiognomonia erythrostoma, show symptoms (translucent-chlorotic leaf spots evolving into rusty areas) very similar to those of cherry chlorotic rusty spot disease (CCRS) and Amasya cherry disease, reported in Italy and Turkey, respectively. The three maladies are closely associated with 10-12 double-stranded viral RNAs, and CCRS is additionally associated with two cherry small circular RNAs (cscRNA1 and cscRNA2). Here, we report that a small viroid-like RNA similar to the CCRS-associated cscRNA1 is also present in CLS-affected trees, thus extending the link between the two diseases. Both CLS and CCRS cscRNA1 elements have common features, including sequence identity (88 %), a predicted quasi rod-like conformation with short bifurcations at both termini, and the presence of hammerhead ribozymes in the strands of both polarities. However, cscRNA2, apparently derived from cscRNA1 by deletion of a short hairpin, was not detected in CLS-affected material. Although the biological nature of cscRNAs is unknown, the identification of at least cscRNA1 in different cherry cultivars and in two distinct geographic areas (Spain and Italy), always in close association with the same mycoviral dsRNAs, supports that these viroid-like RNAs could be satellite RNAs. PMID:24757711

  16. The Umm Al Binni Structure and Bronze Age Catastrophes

    NASA Astrophysics Data System (ADS)

    Hamacher, Duane W.

    Archaeological excavations of sites dating from 2200 BCE and 1200 BCE in the Middle East, Asia Minor, and southeast Europe provide evidence that a large scale disaster affected Bronze Age civilizations. There are numerous debates as to whether this was caused by warfare, a large-scale natural disaster, or some other factor. In 2001, Sharad Master used satellite images to discover a possible Holocene impact structure in the Al 'Amarah marshes of southern Iraq, known as Umm al Binni lake. With an estimated age of < 5000 years and a diameter of ~3.4 km, this structure may help explain this disaster. Using numerical models and scaling equations for a cosmic impact, I show that although destructive forces would have damaged Sumerian cities within a few hundred km of the coast, it is unlikely that this single impact would have caused the large-scale destruction seen over the larger region. The impact origin of the structure is unconfirmed and any connection to Bronze Age catastrophes remains speculative. Errata: Table 4 provides a list of impact sites, three of which are associated with nickel-iron impactors and therefore cannot be from a "fragmented comet".

  17. Elevated CO(2) concentration affects leaf photosynthesis-nitrogen relationships in Pinus taeda over nine years in FACE.

    PubMed

    Crous, Kristine Y; Walters, Michael B; Ellsworth, David S

    2008-04-01

    To investigate whether long-term elevated carbon dioxide concentration ([CO(2)]) causes declines in photosynthetic enhancement and leaf nitrogen (N) owing to limited soil fertility, we measured photosynthesis, carboxylation capacity and area-based leaf nitrogen concentration (N(a)) in Pinus taeda L. growing in a long-term free-air CO(2) enrichment (FACE) facility at an N-limited site. We also determined how maximum rates of carboxylation (V(cmax)) and electron transport (J(max)) varied with N(a) under elevated [CO(2)]. In trees exposed to elevated [CO(2)] for 5 to 9 years, the slope of the relationship between leaf photosynthetic capacity (A(net-Ca)) and N(a) was significantly reduced by 37% in 1-year-old needles, whereas it was unaffected in current-year needles. The slope of the relationships of both V(cmax) and J(max) with N(a) decreased in 1-year-old needles after up to 9 years of growth in elevated [CO(2)], which was accompanied by a 15% reduction in N allocation to the carboxylating enzyme. Nitrogen fertilization (110 kg N ha(-1)) in the ninth year of exposure to elevated [CO(2)] restored the slopes of the relationships of V(cmax) and J(max) with N(a) to those of control trees (i.e., in ambient [CO(2)]). The J(max):V(cmax) ratio was unaffected by either [CO(2)] or N fertilization. Changes in the apparent allocation of N to photosynthetic components may be an important adjustment in pines exposed to elevated [CO(2)] on low-fertility sites. We conclude that fundamental relationships between photosynthesis or its component processes with N(a) may be altered in aging pine needles after more than 5 years of exposure to elevated atmospheric [CO(2)]. PMID:18244946

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

    PubMed

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

    2014-06-01

    We explored the impact of canopy position on leaf respiration (R) and associated traits in tree and shrub species growing in a lowland tropical rainforest in Far North Queensland, Australia. The range of traits quantified included: leaf R in darkness (RD) and in the light (RL; estimated using the Kok method); the temperature (T)-sensitivity of RD; light-saturated photosynthesis (Asat); leaf dry mass per unit area (LMA); and concentrations of leaf nitrogen (N), phosphorus (P), soluble sugars and starch. We found that LMA, and area-based N, P, sugars and starch concentrations were all higher in sun-exposed/upper canopy leaves, compared with their shaded/lower canopy and deep-shade/understory counterparts; similarly, area-based rates of RD, RL and Asat (at 28 °C) were all higher in the upper canopy leaves, indicating higher metabolic capacity in the upper canopy. The extent to which light inhibited R did not differ significantly between upper and lower canopy leaves, with the overall average inhibition being 32% across both canopy levels. Log-log RD-Asat relationships differed between upper and lower canopy leaves, with upper canopy leaves exhibiting higher rates of RD for a given Asat (both on an area and mass basis), as well as higher mass-based rates of RD for a given [N] and [P]. Over the 25-45 °C range, the T-sensitivity of RD was similar in upper and lower canopy leaves, with both canopy positions exhibiting Q10 values near 2.0 (i.e., doubling for every 10 °C rise in T) and Tmax values near 60 °C (i.e., T where RD reached maximal values). Thus, while rates of RD at 28 °C decreased with increasing depth in the canopy, the T-dependence of RD remained constant; these findings have important implications for vegetation-climate models that seek to predict carbon fluxes between tropical lowland rainforests and the atmosphere. PMID:24722001

  19. Corrosion investigation of fire-gilded bronze involving high surface resolution spectroscopic imaging

    NASA Astrophysics Data System (ADS)

    Masi, G.; Chiavari, C.; Avila, J.; Esvan, J.; Raffo, S.; Bignozzi, M. C.; Asensio, M. C.; Robbiola, L.; Martini, C.

    2016-03-01

    Gilded bronzes are often affected by severe corrosion, due to defects in the Au layer and Au/Cu alloy galvanic coupling, stimulated by large cathodic area of the gilded layer. Galvanic corrosion, triggered by gilding defects, leads to products growth at the Au/bronze interface, inducing blistering or break-up of the Au layer. In this context, fire-gilded bronze replicas prepared by ancient methods (use of spreadable Au-Hg paste) was specifically characterised by compiling complementary spectroscopic and imaging information before/after accelerated ageing with synthetic rain. Fire-gilded bronze samples were chemically imaged in cross-section at nano-metric scale (<200 nm) using high energy and lateral resolution synchrotron radiation photoemission (HR-SRPES) of core levels and valence band after conventional characterisation of the samples by Glow Discharge optical Emission Spectroscopy (GD-OES) and conventional X-ray photoelectron spectroscopy (XPS). We have found a net surface enrichment in Zn and Sn after fire-gilding and presence of metallic Hg, Pb and Cu within the Au layer. Moreover, the composition distribution of the elements together with their oxidation has been determined. It was also revealed that metallic phases including Hg and Pb remain in the gilding after corrosion. Moreover, selective dissolution of Zn and Cu occurs in the crater due to galvanic coupling, which locally induces relative Sn species enrichment (decuprification). The feasibility advantages and disadvantages of chemical imaging using HR-SRPES to study artworks have been investigated on representative replicas.

  20. Protection of bronze artefacts through polymeric coatings based on nanocarriers filled with corrosion inhibitors

    NASA Astrophysics Data System (ADS)

    de Luna, Martina Salzano; Buonocore, Giovanna; Di Carlo, Gabriella; Giuliani, Chiara; Ingo, Gabriel M.; Lavorgna, Marino

    2016-05-01

    Protective coatings based on polymers synthesized from renewable sources (chitosan or an amorphous vinyl alcohol based polymer) have been prepared for the protection of bronze artifacts from corrosion. Besides acting as an effective barrier against corrosive species present in the environment, the efficiency of the coatings has been improved by adding corrosion inhibitor compounds (benzotriazole or mercaptobenzothiazole) to the formulations. The liquid medium of the formulations has been carefully selected looking at maximizing the wettability on the bronze substrate and optimizing the solvent evaporation rate. The minimum amount of inhibitor compounds has been optimized by performing accelerated corrosion tests on coated bronze substrates. The inhibitors have been directly dissolved in the coating-forming solutions and/or introduced by means of nanocarriers, which allow to control the release kinetics. The free dissolved inhibitor molecules immediately provide a sufficient protection against corrosion. On the other hand, the inhibitor molecules contained in the nanocarriers serve as long-term reservoir, which can be activated by external corrosion-related stimuli in case of particularly severe conditions. Particular attention has been paid to other features which affect the coating performances. Specifically, the adhesion of the protective polymer layer to the bronze substrate has been assessed, as well as its permeability properties and transparency, the latter being a fundamental feature of protective coating for cultural heritages. Finally, the protective efficiency of the produced smart coatings has been assessed through accelerated corrosion tests.

  1. PGL, encoding chlorophyllide a oxygenase 1, impacts leaf senescence and indirectly affects grain yield and quality in rice.

    PubMed

    Yang, Yaolong; Xu, Jie; Huang, Lichao; Leng, Yujia; Dai, Liping; Rao, Yuchun; Chen, Long; Wang, Yuqiong; Tu, Zhengjun; Hu, Jiang; Ren, Deyong; Zhang, Guangheng; Zhu, Li; Guo, Longbiao; Qian, Qian; Zeng, Dali

    2016-03-01

    Chlorophyll (Chl) b is a ubiquitous accessory pigment in land plants, green algae, and prochlorophytes. This pigment is synthesized from Chl a by chlorophyllide a oxygenase and plays a key role in adaptation to various environments. This study characterizes a rice mutant, pale green leaf (pgl), and isolates the gene PGL by using a map-based cloning approach. PGL, encoding chlorophyllide a oxygenase 1, is mainly expressed in the chlorenchyma and activated in the light-dependent Chl synthesis process. Compared with wild-type plants, pgl exhibits a lower Chl content with a reduced and disorderly thylakoid ultrastructure, which decreases the photosynthesis rate and results in reduced grain yield and quality. In addition, pgl exhibits premature senescence in both natural and dark-induced conditions and more severe Chl degradation and reactive oxygen species accumulation than does the wild-type. Moreover, pgl is sensitive to heat stress. PMID:26709310

  2. PGL, encoding chlorophyllide a oxygenase 1, impacts leaf senescence and indirectly affects grain yield and quality in rice

    PubMed Central

    Yang, Yaolong; Xu, Jie; Huang, Lichao; Leng, Yujia; Dai, Liping; Rao, Yuchun; Chen, Long; Wang, Yuqiong; Tu, Zhengjun; Hu, Jiang; Ren, Deyong; Zhang, Guangheng; Zhu, Li; Guo, Longbiao; Qian, Qian; Zeng, Dali

    2016-01-01

    Chlorophyll (Chl) b is a ubiquitous accessory pigment in land plants, green algae, and prochlorophytes. This pigment is synthesized from Chl a by chlorophyllide a oxygenase and plays a key role in adaptation to various environments. This study characterizes a rice mutant, pale green leaf (pgl), and isolates the gene PGL by using a map-based cloning approach. PGL, encoding chlorophyllide a oxygenase 1, is mainly expressed in the chlorenchyma and activated in the light-dependent Chl synthesis process. Compared with wild-type plants, pgl exhibits a lower Chl content with a reduced and disorderly thylakoid ultrastructure, which decreases the photosynthesis rate and results in reduced grain yield and quality. In addition, pgl exhibits premature senescence in both natural and dark-induced conditions and more severe Chl degradation and reactive oxygen species accumulation than does the wild-type. Moreover, pgl is sensitive to heat stress. PMID:26709310

  3. Leaf biochemistry of Lycopersicon esculentum Mill. at different stages of plant development as affected by mercury treatment.

    PubMed

    Gauba, Nidhi; Mahmooduzzafar; Siddiqi, T O; Umar, S; Iqbal, Muhammad

    2007-04-01

    The effect of mercury (Hg) on the biochemical parameters of Lycopersicon esculentum Mill leaf was studied. Application of mercuric chloride in varying concentrations (0.5, 1.0, 1.5 and 2.0 mM HgCl2 kg(-1) sand) caused significant reduction that went up to 89% and 72% chlorophyll a and chlorophyll b contents respectively (at flowering stage), 69% in carotenoid content, 64% in total soluble protein content and 91% in nitrate reductase activity (all at post-flowering stage). The amounts of nitrate and proline increased maximally (151% and 143% respectively) at the flowering stage, whereas total soluble sugar enhanced by 57% at the post-flowering stage. Changes observed in most of the parameters, were concentration dependent. Such studies seem to be able to discover suitable bioindicators of heavy metal pollution. PMID:17915770

  4. Hydrothermal synthesis of potassium molybdenum oxide bronzes: structure-inheriting solid-state route to blue bronze and dissolution/deposition route to red bronze

    SciTech Connect

    Eda, Kazuo . E-mail: eda@kobe-u.ac.jp; Chin, Kin; Sotani, Noriyuki; Stanley Whittingham, M.

    2005-01-15

    The hydrothermal syntheses of the alkali metal molybdenum bronzes from starting solids (H{sub x}MoO{sub 3}) with structural affinities to the desired products were investigated. Single-phase potassium blue and red bronzes were prepared by the hydrothermal treatments at around 430K, and characterized by powder X-ray diffraction, IR spectroscopy, and SEM. The formation processes of these two bronzes during the hydrothermal treatments were found to differ. The blue bronze was formed by a structure-inheriting solid-state route from H{sub x}MoO{sub 3} with x<0.3, whereas the red bronze was formed for x>0.3 through a solution dissolution/deposition route via the formation of MoO{sub 3}+MoO{sub 2}.

  5. Proteins associated with heat-induced leaf senescence in creeping bentgrass as affected by foliar application of nitrogen, cytokinins, and an ethylene inhibitor.

    PubMed

    Jespersen, David; Huang, Bingru

    2015-02-01

    Heat stress causes premature leaf senescence in cool-season grass species. The objective of this study was to identify proteins regulated by nitrogen, cytokinins, and ethylene inhibitor in relation to heat-induced leaf senescence in creeping bentgrass (Agrostis stolonifera). Plants (cv. Penncross) were foliar sprayed with 18 mM carbonyldiamide (N source), 25 μM aminoethoxyvinylglycine (AVG, ethylene inhibitor), 25 μM zeatin riboside (ZR, cytokinin), or a water control, and then exposed to 20/15°C (day/night) or 35/30°C (heat stress) in growth chambers. All treatments suppressed heat-induced leaf senescence, as shown by higher turf quality and chlorophyll content, and lower electrolyte leakage in treated plants compared to the untreated control. A total of 49 proteins were responsive to N, AVG, or ZR under heat stress. The abundance of proteins in photosynthesis increased, with ribulose-1,5-bisphosphate carboxylase/oxygenase affected by all three treatments, chlorophyll a/b-binding protein by AVG and N or Rubisco activase by AVG. Proteins for amino acid metabolism were upregulated, including alanine aminotransferase by three treatments and ferredoxin-dependent glutamate synthase by AVG and N. Upregulated proteins also included catalase by AVG and N and heat shock protein by ZR. Exogenous applications of AVG, ZR, or N downregulated proteins in respiration (enolase, glyceraldehyde 3-phosphate dehydrogenase, and succinate dehygrogenase) under heat stress. Alleviation of heat-induced senescence by N, AVG, or ZR was associated with enhanced protein abundance in photosynthesis and amino acid metabolism and stress defense systems (heat shock protection and antioxidants), as well as suppression of those imparting respiration metabolism. PMID:25407697

  6. Knockdown of WHIRLY1 Affects Drought Stress-Induced Leaf Senescence and Histone Modifications of the Senescence-Associated Gene HvS40.

    PubMed

    Janack, Bianka; Sosoi, Paula; Krupinska, Karin; Humbeck, Klaus

    2016-01-01

    The plastid-nucleus located protein WHIRLY1 has been described as an upstream regulator of leaf senescence, binding to the promoter of senescence-associated genes like HvS40. To investigate the impact of WHIRLY1 on drought stress-induced, premature senescence, transgenic barley plants with an RNAi-mediated knockdown of the HvWHIRLY1 gene were grown under normal and drought stress conditions. The course of leaf senescence in these lines was monitored by physiological parameters and studies on the expression of senescence- and drought stress-related genes. Drought treatment accelerated leaf senescence in WT plants, whereas WHIRLY 1 knockdown lines (RNAi-W1) showed a stay-green phenotype. Expression of both senescence-associated and drought stress-responsive genes, was delayed in the transgenic plants. Notably, expression of transcription factors of the WRKY and NAC families, which are known to function in senescence- and stress-related signaling pathways, was affected in plants with impaired accumulation of WHIRLY1, indicating that WHIRLY1 acts as an upstream regulator of drought stress-induced senescence. To reveal the epigenetic indexing of HvS40 at the onset of drought-induced senescence in WT and RNAi-W1 lines, stress-responsive loading with histone modifications of promoter and coding sequences of HvS40 was analyzed by chromatin immunoprecipitation and quantified by qRT-PCR. In the wildtype, the euchromatic mark H3K9ac of the HvS40 gene was low under control conditions and was established in response to drought treatment, indicating the action of epigenetic mechanisms in response to drought stress. However, drought stress caused no significant increase in H3K9ac in plants impaired in accumulation of WHIRLY1. The results show that WHIRLY1 knockdown sets in motion a delay in senescence that involves all aspects of gene expression, including changes in chromatin structure. PMID:27608048

  7. Microstructure and wear property of spray formed high leaded bronze

    NASA Astrophysics Data System (ADS)

    Yan, Pengfei; Wang, Deping; Yan, Biao

    2015-03-01

    In this research, Cu-9Pb high leaded bronze were prepared by spray forming. The microstructure and wear properties of this bronze alloy were systematically investigated. The results show that although the hardness of spray formed alloy was not increased comparing with the cast alloy, it still presented a lower wear rate and a lower friction coefficient in dry sliding wear tests as shallower grooves and more lubricating films were observed in the spray formed bronze (BSF14). Spray forming also refined the lead phase microstructure of Cu-9Pb bronze and improved its wear properties.

  8. Enzymatic activities in different strains isolated from healthy and brittle leaf disease affected date palm leaves: study of amylase production conditions.

    PubMed

    Mouna, Jrad; Imen, Fendri; Choba Ines, Ben; Nourredine, Drira; Adel, Kadri; Néji, Gharsallah

    2015-02-01

    The present study aimed to investigate and compare the enzymatic production of endophytic bacteria isolated from healthy and brittle leaf disease affected date palm leaves (pectinase, cellulase, lipase, and amylase). The findings revealed that the enzymatic products from the bacterial isolates of healthy date palm leaves were primarily 33% amylolytic enzyme, 33 % cellulase, 25 % pectinase, and 25 % lipase. The isolates from brittle leaf disease date palm leaves, on the other hand, were noted to produce 16 % amylolytic enzyme, 20 % cellulose, 50 % pectinase, and 50 % lipase. The effects of temperature and pH on amylase, pectinase, and cellulose activities were investigated. The Bacillus subtilis JN934392 strain isolated from healthy date palm leaves produced higher levels of amylase activity at pH 7. A Box Behnken Design (BBD) was employed to optimize amylase extraction. Maximal activity was observed at pH and temperature ranges of pH 6-6.5 and 37-39 °C, respectively. Under those conditions, amylase activity was noted to be attained 9.37 U/ml. The results showed that the enzyme was able to maintain more than 50 % of its activity over a temperature range of 50-80 °C, with an optimum at 70 °C. This bacterial amylase showed high activity compared to other bacteria, which provides support for its promising candidacy for future industrial application. PMID:25432343

  9. Transmission of Tomato Yellow Leaf Curl Virus by Bemisia tabaci as Affected by Whitefly Sex and Biotype

    PubMed Central

    Ning, Wenxi; Shi, Xiaobin; Liu, Baiming; Pan, Huipeng; Wei, Wanting; Zeng, Yang; Sun, Xinpei; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Cheng, Jiaxu; Peng, Zhengke; Zhang, Youjun

    2015-01-01

    Bemisia tabaci is a serious pest of vegetables and other crops worldwide. The most damaging and predominant B. tabaci biotypes are B and Q, and both are vectors of tomato yellow leaf curl virus (TYLCV). Previous research has shown that Q outperforms B in many respects but comparative research is lacking on the ability of B and Q to transmit viruses. In the present study, we tested the hypothesis that B and Q differ in their ability to transmit TYLCV and that this difference helps explain TYLCV outbreaks. We compared the acquisition, retention, and transmission of TYLCV by B and Q females and males. We found that Q females are more efficient than Q males, B females, and B males at TYLCV acquisition and transmission. Although TYLCV acquisition and transmission tended to be greater for B females than B males, the differences were not statistically significant. Based on electrical penetration graphs determination of phloem sap ingestion parameters, females fed better than males, and Q females fed better than Q males, B females, or B males. These results are consistent with the occurrences of TYLCV outbreaks in China, which have been associated with the spread of Q rather than B. PMID:26021483

  10. Transmission of Tomato Yellow Leaf Curl Virus by Bemisia tabaci as Affected by Whitefly Sex and Biotype.

    PubMed

    Ning, Wenxi; Shi, Xiaobin; Liu, Baiming; Pan, Huipeng; Wei, Wanting; Zeng, Yang; Sun, Xinpei; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Cheng, Jiaxu; Peng, Zhengke; Zhang, Youjun

    2015-01-01

    Bemisia tabaci is a serious pest of vegetables and other crops worldwide. The most damaging and predominant B. tabaci biotypes are B and Q, and both are vectors of tomato yellow leaf curl virus (TYLCV). Previous research has shown that Q outperforms B in many respects but comparative research is lacking on the ability of B and Q to transmit viruses. In the present study, we tested the hypothesis that B and Q differ in their ability to transmit TYLCV and that this difference helps explain TYLCV outbreaks. We compared the acquisition, retention, and transmission of TYLCV by B and Q females and males. We found that Q females are more efficient than Q males, B females, and B males at TYLCV acquisition and transmission. Although TYLCV acquisition and transmission tended to be greater for B females than B males, the differences were not statistically significant. Based on electrical penetration graphs determination of phloem sap ingestion parameters, females fed better than males, and Q females fed better than Q males, B females, or B males. These results are consistent with the occurrences of TYLCV outbreaks in China, which have been associated with the spread of Q rather than B. PMID:26021483

  11. Rosmarinus officinalis L. leaf extract improves memory impairment and affects acetylcholinesterase and butyrylcholinesterase activities in rat brain.

    PubMed

    Ozarowski, Marcin; Mikolajczak, Przemyslaw L; Bogacz, Anna; Gryszczynska, Agnieszka; Kujawska, Malgorzata; Jodynis-Liebert, Jadwiga; Piasecka, Anna; Napieczynska, Hanna; Szulc, Michał; Kujawski, Radoslaw; Bartkowiak-Wieczorek, Joanna; Cichocka, Joanna; Bobkiewicz-Kozlowska, Teresa; Czerny, Boguslaw; Mrozikiewicz, Przemyslaw M

    2013-12-01

    Rosmarinus officinalis L. leaf as part of a diet and medication can be a valuable proposal for the prevention and treatment of dementia. The aim of the study was to assess the effects of subchronic (28-fold) administration of a plant extract (RE) (200 mg/kg, p.o.) on behavioral and cognitive responses of rats linked with acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activity and their mRNA expression level in the hippocampus and frontal cortex. The passive avoidance test results showed that RE improved long-term memory in scopolamine-induced rats. The extract inhibited the AChE activity and showed a stimulatory effect on BuChE in both parts of rat brain. Moreover, RE produced a lower mRNA BuChE expression in the cortex and simultaneously an increase in the hippocampus. The study suggests that RE led to improved long-term memory in rats, which can be partially explained by its inhibition of AChE activity in rat brain. PMID:24080468

  12. Solanum tuberosum and Lycopersicon esculentum Leaf Extracts and Single Metabolites Affect Development and Reproduction of Drosophila melanogaster.

    PubMed

    Ventrella, Emanuela; Adamski, Zbigniew; Chudzińska, Ewa; Miądowicz-Kobielska, Mariola; Marciniak, Paweł; Büyükgüzel, Ender; Büyükgüzel, Kemal; Erdem, Meltem; Falabella, Patrizia; Scrano, Laura; Bufo, Sabino Aurelio

    2016-01-01

    Glycoalkaloids are secondary metabolites commonly found in Solanaceae plants. They have anti-bacterial, anti-fungal and insecticidal activities. In the present study we examine the effects of potato and tomato leaf extracts and their main components, the glycoalkaloids α-solanine, α-chaconine and α-tomatine, on development and reproduction of Drosophila melanogaster wild-type flies at different stages. Parental generation was exposed to five different concentrations of tested substances. The effects were examined also on the next, non-exposed generation. In the first (exposed) generation, addition of each extract reduced the number of organisms reaching the pupal and imaginal stages. Parent insects exposed to extracts and metabolites individually applied showed faster development. However, the effect was weaker in case of single metabolites than in case of exposure to extracts. An increase of developmental rate was also observed in the next, non-exposed generation. The imagoes of both generations exposed to extracts and pure metabolites showed some anomalies in body size and malformations, such as deformed wings and abdomens, smaller black abdominal zone. Our results further support the current idea that Solanaceae can be an impressive source of molecules, which could efficaciously be used in crop protection, as natural extract or in formulation of single pure metabolites in sustainable agriculture. PMID:27213896

  13. Solanum tuberosum and Lycopersicon esculentum Leaf Extracts and Single Metabolites Affect Development and Reproduction of Drosophila melanogaster

    PubMed Central

    Ventrella, Emanuela; Adamski, Zbigniew; Chudzińska, Ewa; Miądowicz-Kobielska, Mariola; Marciniak, Paweł; Büyükgüzel, Ender; Büyükgüzel, Kemal; Erdem, Meltem; Falabella, Patrizia; Scrano, Laura; Bufo, Sabino Aurelio

    2016-01-01

    Glycoalkaloids are secondary metabolites commonly found in Solanaceae plants. They have anti-bacterial, anti-fungal and insecticidal activities. In the present study we examine the effects of potato and tomato leaf extracts and their main components, the glycoalkaloids α-solanine, α-chaconine and α-tomatine, on development and reproduction of Drosophila melanogaster wild-type flies at different stages. Parental generation was exposed to five different concentrations of tested substances. The effects were examined also on the next, non-exposed generation. In the first (exposed) generation, addition of each extract reduced the number of organisms reaching the pupal and imaginal stages. Parent insects exposed to extracts and metabolites individually applied showed faster development. However, the effect was weaker in case of single metabolites than in case of exposure to extracts. An increase of developmental rate was also observed in the next, non-exposed generation. The imagoes of both generations exposed to extracts and pure metabolites showed some anomalies in body size and malformations, such as deformed wings and abdomens, smaller black abdominal zone. Our results further support the current idea that Solanaceae can be an impressive source of molecules, which could efficaciously be used in crop protection, as natural extract or in formulation of single pure metabolites in sustainable agriculture. PMID:27213896

  14. Factors affecting population dynamics of leaf beetles in a subarctic region: The interplay between climate warming and pollution decline.

    PubMed

    Zvereva, Elena L; Hunter, Mark D; Zverev, Vitali; Kozlov, Mikhail V

    2016-10-01

    Understanding the mechanisms by which abiotic drivers, such as climate and pollution, influence population dynamics of animals is important for our ability to predict the population trajectories of individual species under different global change scenarios. We monitored four leaf beetle species (Coleoptera: Chrysomelidae) feeding on willows (Salix spp.) in 13 sites along a pollution gradient in subarctic forests of north-western Russia from 1993 to 2014. During a subset of years, we also measured the impacts of natural enemies and host plant quality on the performance of one of these species, Chrysomela lapponica. Spring and fall temperatures increased by 2.5-3°C during the 21-year observation period, while emissions of sulfur dioxide and heavy metals from the nickel-copper smelter at Monchegorsk decreased fivefold. However, contrary to predictions of increasing herbivory with climate warming, and in spite of discovered increase in host plant quality with increase in temperatures, none of the beetle species became more abundant during the past 20years. No directional trends were observed in densities of either Phratora vitellinae or Plagiodera versicolora, whereas densities of both C. lapponica and Gonioctena pallida showed a simultaneous rapid 20-fold decline in the early 2000s, remaining at very low levels thereafter. Time series analysis and model selection indicated that these abrupt population declines were associated with decreases in aerial emissions from the smelter. Observed declines in the population densities of C. lapponica can be explained by increases in mortality from natural enemies due to the combined action of climate warming and declining pollution. This pattern suggests that at least in some tri-trophic systems, top-down factors override bottom-up effects and govern the impacts of environmental changes on insect herbivores. PMID:27266523

  15. Thermal and Electrical Conductivity Measurements of CDA 510 Phosphor Bronze

    NASA Technical Reports Server (NTRS)

    Tuttle, James E.; Canavan, Edgar; DiPirro, Michael

    2009-01-01

    Many cryogenic systems use electrical cables containing phosphor bronze wire. While phosphor bronze's electrical and thermal conductivity values have been published, there is significant variation among different phosphor bronze formulations. The James Webb Space Telescope (JWST) will use several phosphor bronze wire harnesses containing a specific formulation (CDA 510, annealed temper). The heat conducted into the JWST instrument stage is dominated by these harnesses, and approximately half of the harness conductance is due to the phosphor bronze wires. Since the JWST radiators are expected to just keep the instruments at their operating temperature with limited cooling margin, it is important to know the thermal conductivity of the actual alloy being used. We describe an experiment which measured the electrical and thermal conductivity of this material between 4 and 295 Kelvin.

  16. 77 FR 14600 - Pricing for 2012 Kennedy Half-Dollar Bags and Rolls, Bronze Medals, the First Spouse Bronze Medal...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-12

    ... United States Mint Pricing for 2012 Kennedy Half-Dollar Bags and Rolls, Bronze Medals, the First Spouse Bronze Medal Set and the Birth Set AGENCY: United States Mint, Department of the Treasury. ACTION: Notice. SUMMARY: The United States Mint is announcing 2012 pricing for Kennedy Half-Dollar bags and rolls,...

  17. [Sound duration and sound pattern affect the recovery cycles of inferior collicular neurons in leaf-nosed bat, Hipposideros armiger].

    PubMed

    Tang, Jia; Fu, Zi-Ying; Wu, Fei-Jian

    2010-10-25

    The effects of sound duration and sound pattern on the recovery cycles of inferior collicular (IC) neurons in constant frequency-frequency modulation (CF-FM) bats were explored in this study. Five leaf-nosed bats, Hipposideros armiger (4 males, 1 female, 43-50 g body weight), were used as subjects. The extracellular responses of IC neurons to paired sound stimuli with different duration and patterns were recorded, and the recovery was counted as the ratio of the second response to the first response. Totally, 169 sound-sensitive IC neurons were recorded in the experiment. According to the interpulse interval (IPI) of paired sounds when neurons reached 50% recovery (50% IPI), the recovery cycles of these IC neurons were classified into 3 types: fast recovery (F, the 50% IPI was less than 15 ms), short recovery (S, the 50% IPI was between 15.1 and 30 ms) and long recovery (L, the 50% IPI was more than 30 ms). When paired CF stimuli with 2 ms duration was used, the ratio of F neurons was 32.3%, and it decreased to 18.1% and 18.2% respectively when 5 and 7 ms CF stimuli were used. The ratios of S and L neurons were 41.5%, 33.7%, 29.1% and 26.2%, 48.2%, 52.7% respectively when 2, 5 and 7 ms CF stimuli were used. The average 50% IPI determined after stimulation with paired 2 ms, 5 ms and 7 ms CF sounds were (30.2 ± 27.6), (39.9 ± 29.1) and (49.4 ± 34.7) ms, respectively, and the difference among them was significant (P< 0.01). When the stimuli of paired 2 ms CF sounds were shifted to paired 2 ms FM sounds, the proportion of F, S and L neurons changed from 32.3%, 41.5%, 26.2% to 47.7%, 24.6%, 27.7%, respectively, and the average 50% IPI decreased from (30.2 ± 27.6) to (23.9 ± 19.0) ms (P< 0.05, n = 65). When paired 5+2 ms CF-FM pulses were used instead of 7 ms CF sounds, the proportion of F, S and L neurons changed from 18.2%, 29.1%, 52.7% to 29.1%, 27.3%, 43.6%, respectively, and the average 50% IPI decreased from (49.4 ± 34.7) to (36.3 ± 29.4) ms (P< 0.05, n = 55

  18. Summer (subarctic) versus winter (subtropic) production affects spinach (Spinacia oleracea L.) leaf bionutrients: vitamins (C, E, Folate, K1, provitamin A), lutein, phenolics, and antioxidants.

    PubMed

    Lester, Gene E; Makus, Donald J; Hodges, D Mark; Jifon, John L

    2013-07-24

    Comparison of spinach (Spinacia oleracea L.) cultivars Lazio and Samish grown during the summer solstice in the subarctic versus the winter solstice in the subtropics provided insight into interactions between production environment (light intensity), cultivar, and leaf age/maturity/position affecting bionutrient concentrations of vitamins (C, E, folate, K1, provitamin A), lutein, phenolics, and antioxidants. Growing spinach during the winter solstice in the subtropics resulted in increased leaf dry matter %, oxidized (dehydro) ascorbic acid (AsA), α- and γ-tocopherol, and total phenols but lower reduced (free) AsA, α-carotene, folate, and antioxidant capacity compared to summer solstice-grown spinach in the subarctic. Both cultivars had similar bionutrients, except for higher dehydroAsA, and lower α- and γ-tocopherol in 'Samish' compared to 'Lazio'. For most bionutrients measured, there was a linear, and sometimes quadratic, increase in concentrations from bottom to top canopy leaves. However, total phenolics and antioxidant capacity increased basipetally. The current study has thus demonstrated that dehydroAsA, α-tocopherol, and γ-tocopherol were substantially lower in subarctic compared to subtropical-grown spinach, whereas the opposite relationship was found for antioxidant capacity, α-carotene, and folates (vitamin B9). The observations are consistent with previously reported isolated effects of growth environment on bionutrient status of crops. The current results clearly highlight the effect of production environment (predominantly radiation capture), interacting with genetics and plant phenology to alter the bionutrient status of crops. While reflecting the effects of changing growing conditions, these results also indicate potential alterations in the nutritive value of foods with anticipated shifts in global climatic conditions. PMID:23834651

  19. Waterlogging in late dormancy and the early growth phase affected root and leaf morphology in Betula pendula and Betula pubescens seedlings.

    PubMed

    Wang, Ai-Fang; Roitto, Marja; Sutinen, Sirkka; Lehto, Tarja; Heinonen, Jaakko; Zhang, Gang; Repo, Tapani

    2016-01-01

    The warmer winters of the future will increase snow-melt frequency and rainfall, thereby increasing the risk of soil waterlogging and its effects on trees in winter and spring at northern latitudes. We studied the morphology of roots and leaves of 1-year-old silver birch (Betula pendula Roth) and pubescent birch (Betula pubescens Ehrh.) seedlings exposed to waterlogging during dormancy or at the beginning of the growing season in a growth-chamber experiment. The experiment included 4-week dormancy (Weeks 1-4), a 4-week early growing season (Weeks 5-8) and a 4-week late growing season (Weeks 9-12). The treatments were: (i) no waterlogging, throughout the experiment ('NW'); (ii) 4-week waterlogging during dormancy (dormancy waterlogging 'DW'); (iii) 4-week waterlogging during the early growing season (growth waterlogging 'GW'); and (iv) 4-week DW followed by 4-week GW during the early growing season ('DWGW'). Dormancy waterlogging affected the roots of silver birch and GW the roots and leaf characteristics of both species. Leaf area was reduced in both species by GW and DWGW. In pubescent birch, temporarily increased formation of thin roots was seen in root systems of GW seedlings, which suggests an adaptive mechanism with respect to excess soil water. Additionally, the high density of non-glandular trichomes and their increase in DWGW leaves were considered possible morphological adaptations to excess water in the soil, as was the constant density of stem lenticels during stem-diameter growth. The higher density in glandular trichomes of DWGW silver birch suggests morphological acclimation in that species. The naturally low density of non-glandular trichomes, low density of stem lenticels in waterlogged seedlings and decrease in root growth seen in DWGW and DW silver birch seedlings explain, at least partly, why silver birch grows more poorly relative to pubescent birch in wet soils. PMID:26420790

  20. Endocarp thickness affects seed removal speed by small rodents in a warm-temperate broad-leafed deciduous forest, China

    NASA Astrophysics Data System (ADS)

    Zhang, Hongmao; Zhang, Zhibin

    2008-11-01

    Seed traits are important factors affecting seed predation by rodents and thereby the success of recruitment. Seeds of many tree species have hard hulls. These are thought to confer mechanical protection, but the effect of endocarp thickness on seed predation by rodents has not been well investigated. Wild apricot ( Prunus armeniaca), wild peach ( Amygdalus davidiana), cultivated walnut ( Juglans regia), wild walnut ( Juglans mandshurica Maxim) and Liaodong oak ( Quercus liaotungensis) are very common tree species in northwestern Beijing city, China. Their seeds vary greatly in size, endocarp thickness, caloric value and tannin content. This paper aims to study the effects of seed traits on seed removal speed of these five tree species by small rodents in a temperate deciduous forest, with emphasis on the effect of endocarp thickness. The results indicated that speed of removal of seeds released at stations in the field decreased significantly with increasing endocarp thickness. We found no significant correlations between seed removal speed and other seed traits such as seed size, caloric value and tannin content. In seed selection experiments in small cages, Père David's rock squirrel ( Sciurotamias davidianus), a large-bodied, strong-jawed rodent, selected all of the five seed species, and the selection order among the five seed species was determined by endocarp thickness and the ratio of endocarp mass/seed mass. In contrast, the Korean field mouse ( Apodemus peninsulae) and Chinese white-bellied rat ( Niviventer confucianus), with relatively small bodies and weak jaws, preferred to select small seeds like acorns of Q. liaotungensis and seeds of P. armeniaca, indicating that rodent body size is also an important factor affecting food selection based on seed size. These results suggest endocarp thickness significantly reduces seed removal speed by rodents and then negatively affects dispersal fitness of seeds before seed removal of tree species in the study

  1. Silencing of the tomato sugar partitioning affecting protein (SPA) modifies sink strength through a shift in leaf sugar metabolism.

    PubMed

    Bermúdez, Luisa; de Godoy, Fabiana; Baldet, Pierre; Demarco, Diego; Osorio, Sonia; Quadrana, Leandro; Almeida, Juliana; Asis, Ramón; Gibon, Yves; Fernie, Alisdair R; Rossi, Magdalena; Carrari, Fernando

    2014-03-01

    Limitations in our understanding about the mechanisms that underlie source-sink assimilate partitioning are increasingly becoming a major hurdle for crop yield enhancement via metabolic engineering. By means of a comprehensive approach, this work reports the functional characterization of a DnaJ chaperone related-protein (named as SPA; sugar partition-affecting) that is involved in assimilate partitioning in tomato plants. SPA protein was found to be targeted to the chloroplast thylakoid membranes. SPA-RNAi tomato plants produced more and heavier fruits compared with controls, thus resulting in a considerable increment in harvest index. The transgenic plants also displayed increased pigment levels and reduced sucrose, glucose and fructose contents in leaves. Detailed metabolic and enzymatic activities analyses showed that sugar phosphate intermediates were increased while the activity of phosphoglucomutase, sugar kinases and invertases was reduced in the photosynthetic organs of the silenced plants. These changes would be anticipated to promote carbon export from foliar tissues. The combined results suggested that the tomato SPA protein plays an important role in plastid metabolism and mediates the source-sink relationships by affecting the rate of carbon translocation to fruits. PMID:24372694

  2. Acclimations to light quality on plant and leaf level affect the vulnerability of pepper (Capsicum annuum L.) to water deficit.

    PubMed

    Hoffmann, Anna M; Noga, Georg; Hunsche, Mauricio

    2015-03-01

    We investigated the influence of light quality on the vulnerability of pepper plants to water deficit. For this purpose plants were cultivated either under compact fluorescence lamps (CFL) or light-emitting diodes (LED) providing similar photon fluence rates (95 µmol m(-2) s(-1)) but distinct light quality. CFL emit a wide-band spectrum with dominant peaks in the green and red spectral region, whereas LEDs offer narrow band spectra with dominant peaks at blue (445 nm) and red (665 nm) regions. After one-week acclimation to light conditions plants were exposed to water deficit by withholding irrigation; this period was followed by a one-week regeneration period and a second water deficit cycle. In general, plants grown under CFL suffered more from water deficit than plants grown under LED modules, as indicated by the impairment of the photosynthetic efficiency of PSII, resulting in less biomass accumulation compared to respective control plants. As affected by water shortage, plants grown under CFL had a stronger decrease in the electron transport rate (ETR) and more pronounced increase in heat dissipation (NPQ). The higher amount of blue light suppressed plant growth and biomass formation, and consequently reduced the water demand of plants grown under LEDs. Moreover, pepper plants exposed to high blue light underwent adjustments at chloroplast level (e.g., higher Chl a/Chl b ratio), increasing the photosynthetic performance under the LED spectrum. Differently than expected, stomatal conductance was comparable for water-deficit and control plants in both light conditions during the stress and recovery phases, indicating only minor adjustments at the stomatal level. Our results highlight the potential of the target-use of light quality to induce structural and functional acclimations improving plant performance under stress situations. PMID:25626402

  3. Investigation on a "tentacle-like" corrosion feature on Bronze Age tin-bronze objects

    NASA Astrophysics Data System (ADS)

    Piccardo, Paolo; Mödlinger, Marianne; Ghiara, Giorgia; Campodonico, Serena; Bongiorno, Valeria

    2013-12-01

    Studying the micro-structure of Austrian, Bosnian and Croatian Bronze Age objects made of tin bronze, a rare kind of corrosion feature, called in the following "tentacle-like" according to its specific way of penetrating the metallic matrix, was noted and investigated. Differing from the more classical intergranular, pitting, or crevice corrosion features, the "tentacle-like" corrosion is not following the grain boundaries, nor precisely positioned under the etching area, but penetrates mainly the crystal matrix without any apparent order. This paper discusses the first results achieved and the following hypotheses formulated in respect of the typology of this corrosion. The analyses were carried out by optical microscopy, Raman microspectroscopy, and scanning electron microscopy equipped with EDX spectroscopy for quantitative analyses.

  4. 52. photocopy of bronze eagle which later was mounted on ...

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

    52. photocopy of bronze eagle which later was mounted on Tower. Photograph taken at Tacony Iron and Metal Co. works, c. 1892. PCA - The New Public Buildings, Penn Square, Broad & Market Streets, Philadelphia, Philadelphia County, PA

  5. Detail of bronze door on south side of unused section ...

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

    Detail of bronze door on south side of unused section of main lobby. Door accessed stairway leading to Federal Street entrance - Stamford Post Office, 421 Atlantic Street, Stamford, Fairfield County, CT

  6. Limestone and bronze "Mississippi River Crossing" Bridge plaque located at ...

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

    Limestone and bronze "Mississippi River Crossing" Bridge plaque located at North corner of Administration Building site - Huey P. Long Bridge, Administration Building, 5100 Jefferson Highway, Jefferson, Jefferson Parish, LA

  7. Detail view of the bronze gates, lit from behind by ...

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

    Detail view of the bronze gates, lit from behind by the sun - United States Department of Commerce, Bounded by Fourteenth, Fifteenth, and E streets and Constitution Avenue, Washington, District of Columbia, DC

  8. 45. VIEW OF BRONZE BUILDERS PLATE LOCATED ON NORTH SIDE ...

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

    45. VIEW OF BRONZE BUILDERS PLATE LOCATED ON NORTH SIDE AT OUTERMOST END OF WESTERN APPROACH WALL - Tomlinson Bridge, Spanning Quinnipiac River at Forbes Street (U.S. Route 1), New Haven, New Haven County, CT

  9. 25. INTERIOR, FIRST FLOOR, SOUTH ENTRANCE, LOBBY, DETAIL OF BRONZE ...

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

    25. INTERIOR, FIRST FLOOR, SOUTH ENTRANCE, LOBBY, DETAIL OF BRONZE AND GLASS DOORS (4' x 5' negative; 8' x 10' print) - U.S. Department of the Interior, Eighteenth & C Streets Northwest, Washington, District of Columbia, DC

  10. 18. Photocopy of drawing of bronze dedication plaque, circa 1903 ...

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

    18. Photocopy of drawing of bronze dedication plaque, circa 1903 (original drawing in possession of City Engineer's Office Grand Rapids, Michigan) DEDICATION PLAQUE. - Bridge Street Bridge, Spanning Grand River, Michigan & Bridge Streets, Grand Rapids, MI

  11. 30. Bronze plaque located on southern inner wall at east ...

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

    30. Bronze plaque located on southern inner wall at east end of south pier taken looking southeast - Duluth Ship Canal, South Pier, North end of Minnesota Point & Canal Park, Duluth, St. Louis County, MN

  12. Interior view, detail to show the ornate bronze doors to ...

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

    Interior view, detail to show the ornate bronze doors to the entrance lobby elevators - United States Department of Commerce, Bounded by Fourteenth, Fifteenth, and E streets and Constitution Avenue, Washington, District of Columbia, DC

  13. VIEW TO THE SOUTHEAST. MEMORIAL WITH BRONZE PLAQUE IN HONOR ...

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

    VIEW TO THE SOUTHEAST. MEMORIAL WITH BRONZE PLAQUE IN HONOR OF KELLER, MARKS THE CENTER OF THE BRIDGE. - Keller Memorial Bridge, Spanning Tennessee River at U.S. Highway 31, Decatur, Morgan County, AL

  14. 14. DETAIL VIEW OF BRONZE ROLLER GATE GAUGE, LOOKING SOUTHEAST ...

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

    14. DETAIL VIEW OF BRONZE ROLLER GATE GAUGE, LOOKING SOUTHEAST INSIDE ROLLER GATE OPERATING MACHINERY HOUSE - Upper Mississippi River Nine-Foot Channel Project, Lock & Dam No. 25, Cap au Gris, Lincoln County, MO

  15. 12. DETAIL VIEW OF CIRCULAR BRONZE ROLLER GATE POSITION GAUGE, ...

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

    12. DETAIL VIEW OF CIRCULAR BRONZE ROLLER GATE POSITION GAUGE, ROLLER GATE PIER HOUSE, TYPE 2A, DAM - Mississippi River 9-Foot Channel Project, Lock & Dam No. 11, Upper Mississippi River, Dubuque, Dubuque County, IA

  16. 9. Bronze slide expansion plate at Pier 3, on right, ...

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

    9. Bronze slide expansion plate at Pier 3, on right, fixed end left. - Monongahela Connecting Railroad Company, Hot Metal Bridge, Spanning Monongahela River at mile post 3.1, Pittsburgh, Allegheny County, PA

  17. Detail view of bronze door. Note oak branches with acorns ...

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

    Detail view of bronze door. Note oak branches with acorns in the left panels and olive branches with olives in right. - Flanders Field American Cemetery & Memorial, Chapel, Wortegemseweg 117, Waregem, West Flanders (Belgium)

  18. Preparation and evaluation of thin-film sodium tungsten bronzes

    NASA Technical Reports Server (NTRS)

    Kautz, H. E.; Fielder, W. L.; Singer, J.; Fordyce, J. S.

    1974-01-01

    Thin films of sodium tungsten bronze (NaxWO3) were investigated as reversible sodium ion electrodes for solid electrolytes. The films were made by electron beam evaporation of the three phases, W metal, Na2WO4, and WO3, followed by sintering. The substrates were sodium beta alumina disks and glass slides. X-ray diffraction analyses of the films showed that sintering in dry nitrogen with prior exposure to air lead to mixed phases. Sintering in vacuum with no air exposure produced tetragonal I bronze with a nominal composition of Na0.31WO3, single phase within the limits of X-ray diffraction detectability. The films were uniform and adherent on sodium beta alumina substrates. The ac and dc conductivities of the beta alumina were measured with the sodium tungsten bronze films as electrodes. These experiments indicated that the tetragonal I bronze electrodes were not completely reversible. This may have resulted from sodium ion blocking within the bronze film or at the bronze beta alumina interface. Methods for attempting to make more completely reversible electrodes are suggested.

  19. The Decreased apical dominance1/Petunia hybrida CAROTENOID CLEAVAGE DIOXYGENASE8 Gene Affects Branch Production and Plays a Role in Leaf Senescence, Root Growth, and Flower Development

    PubMed Central

    Snowden, Kimberley C.; Simkin, Andrew J.; Janssen, Bart J.; Templeton, Kerry R.; Loucas, Holly M.; Simons, Joanne L.; Karunairetnam, Sakuntala; Gleave, Andrew P.; Clark, David G.; Klee, Harry J.

    2005-01-01

    Carotenoids and carotenoid cleavage products play an important and integral role in plant development. The Decreased apical dominance1 (Dad1)/PhCCD8 gene of petunia (Petunia hybrida) encodes a hypothetical carotenoid cleavage dioxygenase (CCD) and ortholog of the MORE AXILLARY GROWTH4 (MAX4)/AtCCD8 gene. The dad1-1 mutant allele was inactivated by insertion of an unusual transposon (Dad-one transposon), and the dad1-3 allele is a revertant allele of dad1-1. Consistent with its role in producing a graft-transmissible compound that can alter branching, the Dad1/PhCCD8 gene is expressed in root and shoot tissue. This expression is upregulated in the stems of the dad1-1, dad2, and dad3 increased branching mutants, indicating feedback regulation of the gene in this tissue. However, this feedback regulation does not affect the root expression of Dad1/PhCCD8. Overexpression of Dad1/PhCCD8 in the dad1-1 mutant complemented the mutant phenotype, and RNA interference in the wild type resulted in an increased branching phenotype. Other differences in phenotype associated with the loss of Dad1/PhCCD8 function included altered timing of axillary meristem development, delayed leaf senescence, smaller flowers, reduced internode length, and reduced root growth. These data indicate that the substrate(s) and/or product(s) of the Dad1/PhCCD8 enzyme are mobile signal molecules with diverse roles in plant development. PMID:15705953

  20. The effect of uric acid on outdoor copper and bronze.

    PubMed

    Bernardi, E; Bowden, D J; Brimblecombe, P; Kenneally, H; Morselli, L

    2009-03-15

    Bird droppings are often quoted as a decay agent for outdoor goods, in particular buildings and statues. Undoubtedly, they represent one of the major causes of aesthetic damage on outdoor materials, but the real chemical damage they are able to induce, in particular on metals, is not so well studied. This work focused on the short term role of uric acid, the main constituent of bird urine, with respect to copper, which make such an important contribution to architectural elements of buildings and outdoor sculpture. Preliminary results of laboratory tests and analyses on real exposed samples showed that uric acid chemically affects copper and bronzes: the surface of the metal is modified and copper urates formed. Also natural patina, formed on statues and roof, react with uric acid, even if it seems to afford some protection toward bird droppings. In general, experimental results confirm that the potential chemical damage by bird droppings is significant when considering external cultural heritage such as statues, metal monuments and buildings with historic copper roofs. PMID:19157513

  1. European Bronze Age Sheet Metal Objects: 3,000 Years of High-Level Bronze Manufacture

    NASA Astrophysics Data System (ADS)

    Mödlinger, Marianne; El Morr, Ziad

    2014-01-01

    This article focuses on the manufacture and usage of selected sheet metal objects from helmets, a vessel, and two shields from the European Bronze Age and Early Iron Age, which date from the thirteenth to seventh centuries BC. Manufacturing traces on the surface, as well as metallographic investigations and the analyses of the alloy composition with scanning electron microscope-energy-dispersive x-ray spectroscopy, provided an insight into the manufacturing techniques and the production of valuable, high-status objects, and highlighted the potential changes in manufacturing techniques and alloys used during different time periods.

  2. Does leaf position within a canopy affect acclimation of photosynthesis to elevated CO{sub 2}? Analysis of a wheat crop under free-air CO{sub 2} enrichment

    SciTech Connect

    Osborne, C.P.; LaRoche, J.; Hendrey, G.R.; Garcia, R.L.; Kimball, B.A.; Wall, G.W.; Pinter, P.J. Jr.; LaMorte, R.L.; Long, S.P. |

    1998-07-01

    Previous studies of photosynthetic acclimation to elevated CO{sub 2} have focused on the most recently expanded, sunlit leaves in the canopy. The authors examined acclimation in a vertical profile of leaves through a canopy of wheat (Triticum aestivum L.). The crop was grown at an elevated CO{sub 2} partial pressure of 55 Pa within a replicated field experiment using free-air CO{sub 2} enrichment. Gas exchange was used to estimate in vivo carboxylation capacity and the maximum rate of ribulose-1,5-bisphosphate-limited photosynthesis. Net photosynthetic CO{sub 2} uptake was measured for leaves in situ within the canopy. Leaf contents of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), light-harvesting-complex (LHC) proteins, and total N were determined. Elevated CO{sub 2} did not affect carboxylation capacity in the most recently expanded leaves but led to a decrease in lower, shaded leaves during grain development. Despite this acclimation, in situ photosynthetic CO{sub 2} uptake remained higher under elevated CO{sub 2}. Acclimation at elevated CO{sub 2} was accompanied by decreases in both Rubisco and total leaf N contents and an increase in LHC content. Elevated CO{sub 2} led to a larger increase in LHC/Rubisco in lower canopy leaves than in the uppermost leaf. Acclimation of leaf photosynthesis to elevated CO{sub 2} therefore depended on both vertical position within the canopy and the developmental stage.

  3. Release of copper from sintered tungsten-bronze shot under different pH conditions and its potential toxicity to aquatic organisms.

    PubMed

    Thomas, Vernon G; Santore, Robert C; McGill, Ian

    2007-03-01

    Sintered tungsten-bronze is a new substitute for lead shot, and is about to be deposited in and around the wetlands of North America. This material contains copper in the alloyed form of bronze. This in vitro study was performed according to U.S. Fish and Wildlife Service criteria to determine the dissolution rate of copper from the shot, and to assess the toxic risk that it may present to aquatic organisms. The dissolution of copper from tungsten-bronze shot, pure copper shot, and glass beads was measured in a buffered, moderately hard, synthetic water of pH 5.5, 6.6, and 7.8 over a 28-day period. The dissolution of copper from both the control copper shot and the tungsten-bronze shot was affected significantly by the pH of the water and the duration of dissolution (all p values<0.000). The rate of copper release from tungsten bronze shot was 30 to 50 times lower than that from the copper shot, depending on pH (p<0.0000). The observed expected environmental concentration of copper released from tungsten-bronze shot after 28 days was 0.02 microg/L at pH 7.8, and 0.4 microg/L at pH 5.6, using a loading and exposure scenario specific in a U.S. Fish and Wildlife Service protocol. Ratio Quotient values derived from the highest EEC observed in this study (0.4 microg/L), and the copper toxic effect levels for all aquatic species listed in the U.S. Environmental Protection Agency ambient water quality criteria database, were all far less than the 0.1 criterion value. Given the conditions stipulated by the U.S. Fish and Wildlife Service and the U.S. Environmental Protection Agency, heavy loading from discharged tungsten-bronze shot would not pose a toxic risk to potable water, or to soil. Consequently, it would appear that no toxic risks to aquatic organisms will attend the use of tungsten-bronze shot of the approved composition. Given the likelihood that sintered tungsten-bronze of the same formula will be used for fishing weights, bullets, and wheel balance weights, it

  4. Emptying and filling a tunnel bronze

    SciTech Connect

    Marley, Peter M.; Abtew, Tesfaye A.; Farley, Katie E.; Horrocks, Gregory A.; Dennis, Robert V.; Zhang, Peihong; Banerjee, Sarbajit

    2015-01-13

    The classical orthorhombic layered phase of V2O5 has long been regarded as the thermodynamic sink for binary vanadium oxides and has found great practical utility as a result of its open framework and easily accessible redox states. Herein, we exploit a cation-exchange mechanism to synthesize a new stable tunnel-structured polymorph of V2O5 (ζ-V2O5) and demonstrate the subsequent ability of this framework to accommodate Li and Mg ions. The facile extraction and insertion of cations and stabilization of the novel tunnel framework is facilitated by the nanometer-sized dimensions of the materials, which leads to accommodation of strain without amorphization. The topotactic approach demonstrated here indicates not just novel intercalation chemistry accessible at nanoscale dimensions but also suggests a facile synthetic route to ternary vanadium oxide bronzes (MxV2O5) exhibiting intriguing physical properties that range from electronic phase transitions to charge ordering and superconductivity.

  5. Emptying and filling a tunnel bronze

    DOE PAGESBeta

    Marley, Peter M.; Abtew, Tesfaye A.; Farley, Katie E.; Horrocks, Gregory A.; Dennis, Robert V.; Zhang, Peihong; Banerjee, Sarbajit

    2015-01-13

    The classical orthorhombic layered phase of V2O5 has long been regarded as the thermodynamic sink for binary vanadium oxides and has found great practical utility as a result of its open framework and easily accessible redox states. Herein, we exploit a cation-exchange mechanism to synthesize a new stable tunnel-structured polymorph of V2O5 (ζ-V2O5) and demonstrate the subsequent ability of this framework to accommodate Li and Mg ions. The facile extraction and insertion of cations and stabilization of the novel tunnel framework is facilitated by the nanometer-sized dimensions of the materials, which leads to accommodation of strain without amorphization. The topotacticmore » approach demonstrated here indicates not just novel intercalation chemistry accessible at nanoscale dimensions but also suggests a facile synthetic route to ternary vanadium oxide bronzes (MxV2O5) exhibiting intriguing physical properties that range from electronic phase transitions to charge ordering and superconductivity.« less

  6. Preparation of hydrated potassium molybdenum bronzes and their thermal decomposition

    SciTech Connect

    Sotani, Noriyuki; Suzuki, Takashi; Eda, Kazuo

    1997-09-01

    Three kinds of hydrated potassium bronze, K{sub 0.23}(H{sub 2}O){sub 0.65} MoO{sub 3.00} (HyK-AD), K{sub 0.23}(H{sub 2}O){sub 0.43}MoO{sub 3.00}(HyK-H2), and K{sub 0.23}(H{sub 2}O){sub 0.27}MoO{sub 3.00}(HyK-H1), were obtained from hydrated sodium bronzes by cation exchange. Hydrated potassium bronzes dried under vacuum are of two types. The first, HyK-H2 belongs to the six-coordination type and the second, HyK-H1, belongs to the eight-coordination type. When hydrated bronzes were heated in nitrogen, they turned into a mixture of the blue potassium bronze, K{sub 0.3}MoO{sub 3}, and MoO{sub 3}. In contrast, those heated in air decomposed to K{sub 2}Mo{sub 4}O{sub 13} and MoO{sub 3}.

  7. Setup of Galvanic Sensors for the Monitoring of Gilded Bronzes

    PubMed Central

    Goidanich, Sara; Gulotta, Davide; Brambilla, Laura; Beltrami, Ruben; Fermo, Paola; Toniolo, Lucia

    2014-01-01

    Traditional electrochemical techniques, such as linear polarization resistance (Rp), and electrochemical impedance spectroscopy (EIS), cannot be applied to gilded bronzes, as it may not be possible to interpret the results obtained due to the bimetallic nature of the studied material. The measurement of the macrocouple current generated by the gold/bronze galvanic couple can be used as an indicator of degradation processes. Nevertheless, this measurement cannot be performed directly on the original artifacts due to the systematic presence of short-circuits between the two metals. In the present work the use of galvanic sensors is proposed as a possible solution for the monitoring of gilded bronze artefacts. The sensors have been designed to simulate real gilded bronze surfaces in terms of composition and stratigraphy and have proved to be a reliable diagnostic tool for the in situ monitoring of the rates of deterioration of gilded bronze surfaces and to test new conservation treatments. Their set-up and application is reported and their performances discussed. PMID:24759110

  8. 76 FR 40402 - Matthews International Corporation, Bronze Division, Kingwood, WV; Notice of Negative...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-07-08

    ..., 2011 (76 FR 7584). Workers were engaged in the production of cast bronze memorial products. The initial... Employment and Training Administration TA-W-72,953 Matthews International Corporation, Bronze Division... former workers of Matthews International Corporation, Bronze ] Division, Kingwood, West Virginia...

  9. Octahedral tilting in the tungsten bronzes.

    PubMed

    Whittle, Thomas A; Schmid, Siegbert; Howard, Christopher J

    2015-06-01

    Possibilities for 'simple' octahedral tilting in the hexagonal and tetragonal tungsten bronzes (HTB and TTB) have been examined, making use of group theory as implemented in the computer program ISOTROPY. For HTB, there is one obvious tilting pattern, leading to a structure in space group P6₃/mmc. This differs from the space group P6₃/mcm frequently quoted from X-ray studies – these studies have in effect detected only displacements of the W cations from the centres of the WO6 octahedra. The correct space group, taking account of both W ion displacement and the octahedral tilting, is P6₃22 – structures in this space group and matching this description have been reported. A second acceptable tilting pattern has been found, leading to a structure in P6/mmm but on a larger '2 × 2 × 2' unit cell – however, no observations of this structure have been reported. For TTB, a search at the special points of the Brillouin zones revealed only one comparable tilting pattern, in a structure with space-group symmetry I4/m on a '2(1/2) × 2(1/2) by 2' unit cell. Given several literature reports of larger unit cells for TTB, we conducted a limited search along the lines of symmetry and found structures with acceptable tilt patterns in Bbmm on a '2(1/2)2 × 2(1/2) × 2' unit cell. A non-centrosymmetric version has been reported in niobates, in Bbm2 on the same unit cell. PMID:26027010

  10. Leaf Development

    PubMed Central

    2013-01-01

    Leaves are the most important organs for plants. Without leaves, plants cannot capture light energy or synthesize organic compounds via photosynthesis. Without leaves, plants would be unable perceive diverse environmental conditions, particularly those relating to light quality/quantity. Without leaves, plants would not be able to flower because all floral organs are modified leaves. Arabidopsis thaliana is a good model system for analyzing mechanisms of eudicotyledonous, simple-leaf development. The first section of this review provides a brief history of studies on development in Arabidopsis leaves. This history largely coincides with a general history of advancement in understanding of the genetic mechanisms operating during simple-leaf development in angiosperms. In the second section, I outline events in Arabidopsis leaf development, with emphasis on genetic controls. Current knowledge of six important components in these developmental events is summarized in detail, followed by concluding remarks and perspectives. PMID:23864837

  11. Early Bronze Age Dolmens in Jordan and their orientations

    NASA Astrophysics Data System (ADS)

    Polcaro, A.; Polcaro, F.

    This work presents the results of a survey of dolmen fields of the Early Bronze I in Jordan, in the Wadi Zarqa Valley, started in October 2004 and still in progress. Our data show, with a very high statistical significance, that in many sites of the Early Bronze IA a large majority of dolmens were built oriented along the N-S direction. A first interpretative hypothesis of these results, based on the astronomical contents of the mythology of the nearby civilizations culturally connected to the Palestinian area, is suggested.

  12. Electronic band structure and charge density wave transition in quasi-2D KMo6O17 purple bronze

    NASA Astrophysics Data System (ADS)

    Valbuena, M. A.; Avila, J.; Vyalikh, D. V.; Guyot, H.; Laubschat, C.; Molodtsov, S. L.; Asensio, M. C.

    2008-03-01

    High resolution angle-resolved photoemission of quasi-2D KMo6O17 purple bronze has been performed in the range from room temperature to 130 K, slightly above the charge density wave (CDW) transition (Tc = 110 K), and down to 35 K (well below Tc). In this paper we report a detailed study of how electronic band structure is affected by this transition driven by the hidden nesting scenario. The expected spectroscopic fingerprints of the CDW phase transition have been found and discussed according to the hidden one dimension and the development of a quasi-commensurate CDW. The excellent agreement between theory and our experimental results makes of potassium purple bronze a reference system for studying this type of instabilities.

  13. Effect of herbivore damage on broad leaf motion in wind

    NASA Astrophysics Data System (ADS)

    Burnett, Nicholas; Kothari, Adit

    2015-11-01

    Terrestrial plants regularly experience wind that imposes aerodynamic forces on the plants' leaves. Passive leaf motion (e.g. fluttering) and reconfiguration (e.g. rolling into a cone shape) in wind can affect the drag on the leaf. In the study of passive leaf motion in wind, little attention has been given to the effect of herbivory. Herbivores may alter leaf motion in wind by making holes in the leaf. Also, a small herbivore (e.g. snail) on a leaf can act as a point mass, thereby affecting the leaf's motion in wind. Conversely, accelerations imposed on an herbivore sitting on a leaf by the moving leaf may serve as a defense by dislodging the herbivore. In the present study, we investigated how point masses (>1 g) and holes in leaves of the tuliptree affected passive leaf motion in turbulent winds of 1 and 5 m s-1. Leaf motion was unaffected by holes in the leaf surface (about 10% of leaf area), but an herbivore's mass significantly damped the accelerations of fluttering leaves. These results suggest that an herbivore's mass, but not the damage it inflicts, can affect leaf motion in the wind. Furthermore, the damping of leaf fluttering from an herbivore's mass may prevent passive leaf motions from being an effective herbivore defense.

  14. Origin of the mysterious Yin-Shang bronzes in China indicated by lead isotopes

    PubMed Central

    Sun, Wei-dong; Zhang, Li-peng; Guo, Jia; Li, Cong-ying; Jiang, Yu-hang; Zartman, Robert E.; Zhang, Zhao-feng

    2016-01-01

    Fine Yin-Shang bronzes containing lead with puzzlingly highly radiogenic isotopic compositions appeared suddenly in the alluvial plain of the Yellow River around 1400 BC. The Tongkuangyu copper deposit in central China is known to have lead isotopic compositions even more radiogenic and scattered than those of the Yin-Shang bronzes. Most of the Yin-Shang bronzes are tin-copper alloys with high lead contents. The low lead and tin concentrations, together with the less radiogenic lead isotopes of bronzes in an ancient smelting site nearby, however, exclude Tongkuangyu as the sole supplier of the Yin-Shang bronzes. Interestingly, tin ingots/prills and bronzes found in Africa also have highly radiogenic lead isotopes, but it remains mysterious as to how such African bronzes may have been transported to China. Nevertheless, these African bronzes are the only bronzes outside China so far reported that have lead isotopes similar to those of the Yin-Shang bronzes. All these radiogenic lead isotopes plot along ~2.0–2.5 Ga isochron lines, implying that deposits around Archean cratons are the most likely candidates for the sources. African cratons along the Nile and even micro-cratons in the Sahara desert may have similar lead signatures. These places were probably accessible by ancient civilizations, and thus are the most favorable suppliers of the bronzes. PMID:26988425

  15. Origin of the mysterious Yin-Shang bronzes in China indicated by lead isotopes.

    PubMed

    Sun, Wei-Dong; Zhang, Li-Peng; Guo, Jia; Li, Cong-Ying; Jiang, Yu-Hang; Zartman, Robert E; Zhang, Zhao-Feng

    2016-01-01

    Fine Yin-Shang bronzes containing lead with puzzlingly highly radiogenic isotopic compositions appeared suddenly in the alluvial plain of the Yellow River around 1400 BC. The Tongkuangyu copper deposit in central China is known to have lead isotopic compositions even more radiogenic and scattered than those of the Yin-Shang bronzes. Most of the Yin-Shang bronzes are tin-copper alloys with high lead contents. The low lead and tin concentrations, together with the less radiogenic lead isotopes of bronzes in an ancient smelting site nearby, however, exclude Tongkuangyu as the sole supplier of the Yin-Shang bronzes. Interestingly, tin ingots/prills and bronzes found in Africa also have highly radiogenic lead isotopes, but it remains mysterious as to how such African bronzes may have been transported to China. Nevertheless, these African bronzes are the only bronzes outside China so far reported that have lead isotopes similar to those of the Yin-Shang bronzes. All these radiogenic lead isotopes plot along ~2.0-2.5 Ga isochron lines, implying that deposits around Archean cratons are the most likely candidates for the sources. African cratons along the Nile and even micro-cratons in the Sahara desert may have similar lead signatures. These places were probably accessible by ancient civilizations, and thus are the most favorable suppliers of the bronzes. PMID:26988425

  16. Origin of the mysterious Yin-Shang bronzes in China indicated by lead isotopes

    NASA Astrophysics Data System (ADS)

    Sun, Wei-Dong; Zhang, Li-Peng; Guo, Jia; Li, Cong-Ying; Jiang, Yu-Hang; Zartman, Robert E.; Zhang, Zhao-Feng

    2016-03-01

    Fine Yin-Shang bronzes containing lead with puzzlingly highly radiogenic isotopic compositions appeared suddenly in the alluvial plain of the Yellow River around 1400 BC. The Tongkuangyu copper deposit in central China is known to have lead isotopic compositions even more radiogenic and scattered than those of the Yin-Shang bronzes. Most of the Yin-Shang bronzes are tin-copper alloys with high lead contents. The low lead and tin concentrations, together with the less radiogenic lead isotopes of bronzes in an ancient smelting site nearby, however, exclude Tongkuangyu as the sole supplier of the Yin-Shang bronzes. Interestingly, tin ingots/prills and bronzes found in Africa also have highly radiogenic lead isotopes, but it remains mysterious as to how such African bronzes may have been transported to China. Nevertheless, these African bronzes are the only bronzes outside China so far reported that have lead isotopes similar to those of the Yin-Shang bronzes. All these radiogenic lead isotopes plot along ~2.0–2.5 Ga isochron lines, implying that deposits around Archean cratons are the most likely candidates for the sources. African cratons along the Nile and even micro-cratons in the Sahara desert may have similar lead signatures. These places were probably accessible by ancient civilizations, and thus are the most favorable suppliers of the bronzes.

  17. SPAD-based leaf nitrogen estimation is impacted by environmental factors and crop leaf characteristics

    PubMed Central

    Xiong, Dongliang; Chen, Jia; Yu, Tingting; Gao, Wanlin; Ling, Xiaoxia; Li, Yong; Peng, Shaobing; Huang, Jianliang

    2015-01-01

    Chlorophyll meters are widely used to guide nitrogen (N) management by monitoring leaf N status in agricultural systems, but the effects of environmental factors and leaf characteristics on leaf N estimations are still unclear. In the present study, we estimated the relationships among SPAD readings, chlorophyll content and leaf N content per leaf area for seven species grown in multiple environments. There were similar relationships between SPAD readings and chlorophyll content per leaf area for the species groups, but the relationship between chlorophyll content and leaf N content per leaf area, and the relationship between SPAD readings and leaf N content per leaf area varied widely among the species groups. A significant impact of light-dependent chloroplast movement on SPAD readings was observed under low leaf N supplementation in both rice and soybean but not under high N supplementation. Furthermore, the allocation of leaf N to chlorophyll was strongly influenced by short-term changes in growth light. We demonstrate that the relationship between SPAD readings and leaf N content per leaf area is profoundly affected by environmental factors and leaf features of crop species, which should be accounted for when using a chlorophyll meter to guide N management in agricultural systems. PMID:26303807

  18. INTERIOR DETAIL, EASTERN HEMICYCLE, SALOON. WILLIAM HAMILTON PLACED BRONZE AND ...

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

    INTERIOR DETAIL, EASTERN HEMICYCLE, SALOON. WILLIAM HAMILTON PLACED BRONZE AND MARBLE SCULPTURE IN SOME OF THE HEMICYCLE NICHES. ONE OF THE NICHES HOUSED A “CANNON STOVE” FOR HEATING THE ROOM IN THE COLDER MONTHS - The Woodlands, 4000 Woodlands Avenue, Philadelphia, Philadelphia County, PA

  19. DETAIL OF ORIGINAL PHOSPHOR BRONZE PLATE PLACED OVER A BULLSEYE ...

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

    DETAIL OF ORIGINAL PHOSPHOR BRONZE PLATE PLACED OVER A BULLSEYE REFLECTOR THAT WAS AIMED AT ONCOMING TRAFFIC. THE TOP OF A CIRCULAR VOID CAN BE SEEN BELOW THE PLATE WHERE THE REFLECTOR WAS REMOVED. VIEW FACING SOUTHWEST. - Waikele Canal Bridge and Highway Overpass, Farrington Highway and Waikele Stream, Waipahu, Honolulu County, HI

  20. Detail view to show the bronze gates hanging in the ...

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

    Detail view to show the bronze gates hanging in the driveway portals; the open grille is foliated and crowned with patriotic eagle emblems - United States Department of Commerce, Bounded by Fourteenth, Fifteenth, and E streets and Constitution Avenue, Washington, District of Columbia, DC

  1. BRONZE FOUNDRY SCRAP STORED IN THE BINS TO THE RIGHT ...

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

    BRONZE FOUNDRY SCRAP STORED IN THE BINS TO THE RIGHT ARE LOADED INTO THE BOTTOM DROPPING CHARGE BUCKET IN THE BACKGROUND BEFORE BEING CHARGED INTO ONE OF THE ELECTRIC ARC FURNACES. - Stockham Pipe & Fittings Company, Brass Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  2. VIEW OF A BRONZE PLAQUE LOCATED AT THE FRONT OF ...

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

    VIEW OF A BRONZE PLAQUE LOCATED AT THE FRONT OF BUILDING 708. PLAQUE IS MOUNTED ON THE WALL JUST TO THE RIGHT SIDE OF THE CHAPEL'S ENTRANCE. - U.S. Naval Base, Pearl Harbor, Chapel, Corner of Oakley & Nimitz Street, Pearl City, Honolulu County, HI

  3. TILTING ELECTRIC ARC FURNACE USED TO MELT BRONZE IN THE ...

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

    TILTING ELECTRIC ARC FURNACE USED TO MELT BRONZE IN THE BRASS FOUNDRY BY MEANS OF AN ARC CREATED BETWEEN TWO HORIZONTAL ELECTRODES. WHEN MELTED, THE FURNACE TILTS, FILLING MOBILE LADLES FROM THE SPOUT. - Stockham Pipe & Fittings Company, Brass Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  4. Formation of tetragonal hydrogen tungsten bronze by reactive mechanical alloying

    SciTech Connect

    Urretavizcaya, G. Tonus, F.; Gaudin, E.; Bobet, J.-L.; Castro, F.J.

    2007-10-15

    Hydrogen tungsten bronzes have been synthesized by reactive mechanical alloying monoclinic tungsten (VI) oxide under hydrogen atmosphere. Two milling devices with different energy ranges were used. Regardless of the distinct reaction times, a similar phase evolution was observed with both apparatus. The characterization of the materials was performed by XRD, SEM, DSC and total hydrogen content determination. The final product obtained was a mixture of tetragonal H{sub 0.33}WO{sub 3} and H{sub 0.23}WO{sub 3} bronzes. - Graphical abstract: Hydrogen tungsten bronzes have been synthesized by reactive mechanical alloying (RMA) monoclinic WO{sub 3} under H{sub 2} atmosphere. By using two milling devices with different energy ranges a similar phase evolution with distinct reaction times was observed. The materials were characterized by XRD, SEM, DSC and total hydrogen content determination. The final product obtained was a mixture of tetragonal H{sub 0.33}WO{sub 3} and H{sub 0.23}WO{sub 3} bronzes. Display Omitted.

  5. Going for the Bronze: A Study of Frederic Remington's Sculptures.

    ERIC Educational Resources Information Center

    Turner, Dianne

    2002-01-01

    Provides background information on the artist Frederic Remington who was fascinated with the Old West in the United States. Discusses how students can learn about Remington, his art, and the Old West. Presents an art lesson where students create their own bronze horse sculptures in the style of Remington. (CMK)

  6. 17. DETAIL OF THE BRONZE INSCRIPTION PLACQUE, LOCATED IN A ...

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

    17. DETAIL OF THE BRONZE INSCRIPTION PLACQUE, LOCATED IN A NEWEL ON THE SOUTH END OF THE BRIDGE. ALTHOUGH THE DATE ON THE PLACQUE IS 1929, THE BRIDGE WAS NOT DEDICATED UNTIL 1930. - County Line Bridge, Spanning St. Joseph River at State Route 219, 0.6 mile south of U.S. Route 20, Osceola, St. Joseph County, IN

  7. 26. A PHOTOGRAPH OF ONE OF THE TWO BRONZE, LOWRELIEF ...

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

    26. A PHOTOGRAPH OF ONE OF THE TWO BRONZE, LOW-RELIEF COMMEMORATIVE PLACQUES WHICH ARE MOUNTED ON PEDESTALS AT THE NORTHEAST AND SOUTHWEST ENDS OF THE BRIDGE. NOTE THE PRONOUNCED PEBBLE-DASH FINISH ON THE CONCRETE WHICH WAS CREATED, IN PART, BY WASHING THE DAMP CASTINGS. - Main Street Bridge, Spanning East Fork Whitewater River, Richmond, Wayne County, IN

  8. BRASS FOUNDRY BUILDING WHERE STOCKHAM MANUFACTURED ITS BRONZE VALVES AND ...

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

    BRASS FOUNDRY BUILDING WHERE STOCKHAM MANUFACTURED ITS BRONZE VALVES AND VALVE PARTS. ALTHOUGH THE COMPANY DID NOT PRODUCE BRASS CASTINGS, ITS EQUIPMENT WAS SIMILAR TO THAT USED IN BRASS FOUNDRIES AND MAY HAVE BEEN PART OF LONG RANGE PLAN TO CAST BRASS. - Stockham Pipe & Fittings Company, Brass Foundry, 4000 Tenth Avenue North, Birmingham, Jefferson County, AL

  9. BRONZE WILT AS A CAUSE OF YIELD STAGNATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cultivars and breeding lines submitted for the 2000 Uniform Variety Trials were inoculated with Agrobacterium tumefaciens isolate 25A, grown in the greenhouse, and observed for plant development, yield, seed quality, bronze wilt, root necrosis, and bacterial concentration in roots. Losses from bron...

  10. Reporting Casting Bronze Plaque Becomes Advisers Class Project

    ERIC Educational Resources Information Center

    Ross, Charlie

    1977-01-01

    Describes an advisers' class project (at the University of Oklahoma) which consisted of reporting on the casting of a bronze plaque bearing the names of the first school newspaper, "The Students Gazette," and its editor, Samuel M. Fox, for presentation in Philadelphia to commemorate scholastic journalism's Bicentennial. (MB)

  11. Community Geothermal Technology Program: Silica bronze project. Final report

    SciTech Connect

    Bianchini, H.

    1989-10-01

    Objective was to incorporate waste silica from the HGP-A geothermal well in Pohoiki with other refractory materials for investment casting of bronze sculpture. The best composition for casting is about 50% silica, 25% red cinders, and 25% brick dust; remaining ingredient is a binder, such as plaster and water.

  12. Alterations of the gut microbiome of largemouth bronze gudgeon (Coreius guichenoti) suffering from furunculosis

    PubMed Central

    Li, Tongtong; Long, Meng; Ji, Cheng; Shen, Zhixin; Gatesoupe, François-Joël; Zhang, Xujie; Zhang, Qianqian; Zhang, Lanli; Zhao, Yuanli; Liu, Xinhua; Li, Aihua

    2016-01-01

    High-throughput sequencing was applied to compare the intestinal microbiota in largemouth bronze gudgeon either healthy or affected by furunculosis. Proteobacteria, Actinobacteria, Tenericutes, Firmicutes and Bacteroidetes were detected as the predominant bacterial phyla in the gut of both diseased and healthy fish. The abundance of Proteobacteria differed significantly between the two groups of fish, mainly due to the overwhelming prevalence of Aeromonas in the diseased fish (81% ± 17%), while the genus was unevenly spread among the apparently healthy fish (33% ± 33%). The bacterial diversity in the intestine of diseased fish was markedly lower than in healthy fish. Analysis revealed the significant dissimilarity between the gut microbiota of diseased and healthy fish. The bacterial profiles in the gut were further characterized with the 28 phylotypes that were shared by the two groups. In diseased fish, two shared OTUs (OTU0001 and OTU0013) were closely related to Aeromonas salmonicida, their total proportion exceeding 70% of the sequences in diseased fish, while averaging 5.2% ± 4.6% in the healthy fish. This result suggested the presence of healthy carriers of pathogenic A. salmonicida among the farmed fish, and the gut appeared as a probable infection source for furunculosis in largemouth bronze gudgeon. PMID:27465687

  13. Alterations of the gut microbiome of largemouth bronze gudgeon (Coreius guichenoti) suffering from furunculosis.

    PubMed

    Li, Tongtong; Long, Meng; Ji, Cheng; Shen, Zhixin; Gatesoupe, François-Joël; Zhang, Xujie; Zhang, Qianqian; Zhang, Lanli; Zhao, Yuanli; Liu, Xinhua; Li, Aihua

    2016-01-01

    High-throughput sequencing was applied to compare the intestinal microbiota in largemouth bronze gudgeon either healthy or affected by furunculosis. Proteobacteria, Actinobacteria, Tenericutes, Firmicutes and Bacteroidetes were detected as the predominant bacterial phyla in the gut of both diseased and healthy fish. The abundance of Proteobacteria differed significantly between the two groups of fish, mainly due to the overwhelming prevalence of Aeromonas in the diseased fish (81% ± 17%), while the genus was unevenly spread among the apparently healthy fish (33% ± 33%). The bacterial diversity in the intestine of diseased fish was markedly lower than in healthy fish. Analysis revealed the significant dissimilarity between the gut microbiota of diseased and healthy fish. The bacterial profiles in the gut were further characterized with the 28 phylotypes that were shared by the two groups. In diseased fish, two shared OTUs (OTU0001 and OTU0013) were closely related to Aeromonas salmonicida, their total proportion exceeding 70% of the sequences in diseased fish, while averaging 5.2% ± 4.6% in the healthy fish. This result suggested the presence of healthy carriers of pathogenic A. salmonicida among the farmed fish, and the gut appeared as a probable infection source for furunculosis in largemouth bronze gudgeon. PMID:27465687

  14. Prehistoric contacts over the Straits of Gibraltar indicated by genetic analysis of Iberian Bronze Age cattle

    PubMed Central

    Anderung, Cecilia; Bouwman, Abigail; Persson, Per; Carretero, José Miguel; Ortega, Ana Isabel; Elburg, Rengert; Smith, Colin; Arsuaga, Juan Luis; Ellegren, Hans; Götherström, Anders

    2005-01-01

    The geographic situation of the Iberian Peninsula makes it a natural link between Europe and North Africa. However, it is a matter of debate to what extent African influences via the Straits Gibraltar have affected Iberia's prehistoric development. Because early African pastoralist communities were dedicated to cattle breeding, a possible means to detect prehistoric African–Iberian contacts might be to analyze the origin of cattle breeds on the Iberian Peninsula. Some contemporary Iberian cattle breeds show a mtDNA haplotype, T1, that is characteristic to African breeds, generally explained as being the result of the Muslim expansion of the 8th century A.D., and of modern imports. To test a possible earlier African influence, we analyzed mtDNA of Bronze Age cattle from the Portalón cave at the Atapuerca site in northern Spain. Although the majority of samples showed the haplotype T3 that dominates among European breeds of today, the T1 haplotype was found in one specimen radiocarbon dated 1800 calibrated years B.C. Accepting T1 as being of African origin, this result indicates prehistoric African–Iberian contacts and lends support to archaeological finds linking early African and Iberian cultures. We also found a wild ox haplotype in the Iberian Bronze Age sample, reflecting local hybridization or backcrossing or that aurochs were hunted by these farming cultures. PMID:15941827

  15. LeafJ: an ImageJ plugin for semi-automated leaf shape measurement.

    PubMed

    Maloof, Julin N; Nozue, Kazunari; Mumbach, Maxwell R; Palmer, Christine M

    2013-01-01

    High throughput phenotyping (phenomics) is a powerful tool for linking genes to their functions (see review and recent examples). Leaves are the primary photosynthetic organ, and their size and shape vary developmentally and environmentally within a plant. For these reasons studies on leaf morphology require measurement of multiple parameters from numerous leaves, which is best done by semi-automated phenomics tools. Canopy shade is an important environmental cue that affects plant architecture and life history; the suite of responses is collectively called the shade avoidance syndrome (SAS). Among SAS responses, shade induced leaf petiole elongation and changes in blade area are particularly useful as indices. To date, leaf shape programs (e.g. SHAPE, LAMINA, LeafAnalyzer, LEAFPROCESSOR) can measure leaf outlines and categorize leaf shapes, but can not output petiole length. Lack of large-scale measurement systems of leaf petioles has inhibited phenomics approaches to SAS research. In this paper, we describe a newly developed ImageJ plugin, called LeafJ, which can rapidly measure petiole length and leaf blade parameters of the model plant Arabidopsis thaliana. For the occasional leaf that required manual correction of the petiole/leaf blade boundary we used a touch-screen tablet. Further, leaf cell shape and leaf cell numbers are important determinants of leaf size. Separate from LeafJ we also present a protocol for using a touch-screen tablet for measuring cell shape, area, and size. Our leaf trait measurement system is not limited to shade-avoidance research and will accelerate leaf phenotyping of many mutants and screening plants by leaf phenotyping. PMID:23380664

  16. Identification of Plants That Inhibit Lipid Droplet Formation in Liver Cells: Rubus suavissimus Leaf Extract Protects Mice from High-Fat Diet-Induced Fatty Liver by Directly Affecting Liver Cells

    PubMed Central

    Takahashi, Tomohiro; Sugawara, Wataru; Takiguchi, Yuya; Takizawa, Kento; Nakabayashi, Ami; Nakamura, Mitsuo; Nagano-Ito, Michiyo; Ichikawa, Shinichi

    2016-01-01

    Fatty liver disease is a condition in which abnormally large numbers of lipid droplets accumulate in liver cells. Fatty liver disease induces inflammation under conditions of oxidative stress and may result in cancer. To identify plants that protect against fatty liver disease, we examined the inhibitory effects of plant extracts on lipid droplet formation in mouse hepatoma cells. A screen of 98 water extracts of plants revealed 4 extracts with inhibitory effects. One of these extracts, Rubus suavissimus S. Lee (Tien-cha or Chinese sweet tea) leaf extract, which showed strong inhibitory effects, was tested in a mouse fatty liver model. In these mouse experiments, intake of the plant extract significantly protected mice against fatty liver disease without affecting body weight gain. Our results suggest that RSE directly affects liver cells and protects them from fatty liver disease. PMID:27429636

  17. Identification of Plants That Inhibit Lipid Droplet Formation in Liver Cells: Rubus suavissimus Leaf Extract Protects Mice from High-Fat Diet-Induced Fatty Liver by Directly Affecting Liver Cells.

    PubMed

    Takahashi, Tomohiro; Sugawara, Wataru; Takiguchi, Yuya; Takizawa, Kento; Nakabayashi, Ami; Nakamura, Mitsuo; Nagano-Ito, Michiyo; Ichikawa, Shinichi

    2016-01-01

    Fatty liver disease is a condition in which abnormally large numbers of lipid droplets accumulate in liver cells. Fatty liver disease induces inflammation under conditions of oxidative stress and may result in cancer. To identify plants that protect against fatty liver disease, we examined the inhibitory effects of plant extracts on lipid droplet formation in mouse hepatoma cells. A screen of 98 water extracts of plants revealed 4 extracts with inhibitory effects. One of these extracts, Rubus suavissimus S. Lee (Tien-cha or Chinese sweet tea) leaf extract, which showed strong inhibitory effects, was tested in a mouse fatty liver model. In these mouse experiments, intake of the plant extract significantly protected mice against fatty liver disease without affecting body weight gain. Our results suggest that RSE directly affects liver cells and protects them from fatty liver disease. PMID:27429636

  18. Rewriting the Central European Early Bronze Age Chronology: Evidence from Large-Scale Radiocarbon Dating

    PubMed Central

    Knipper, Corina; Friedrich, Ronny; Kromer, Bernd; Lindauer, Susanne; Radosavljević, Jelena; Wittenborn, Fabian; Krause, Johannes

    2015-01-01

    The transition from the Neolithic to the Early Bronze Age in Central Europe has often been considered as a supra-regional uniform process, which led to the growing mastery of the new bronze technology. Since the 1920s, archaeologists have divided the Early Bronze Age into two chronological phases (Bronze A1 and A2), which were also seen as stages of technical progress. On the basis of the early radiocarbon dates from the cemetery of Singen, southern Germany, the beginning of the Early Bronze Age in Central Europe was originally dated around 2300/2200 BC and the transition to more complex casting techniques (i.e., Bronze A2) around 2000 BC. On the basis of 140 newly radiocarbon dated human remains from Final Neolithic, Early and Middle Bronze Age cemeteries south of Augsburg (Bavaria) and a re-dating of ten graves from the cemetery of Singen, we propose a significantly different dating range, which forces us to re-think the traditional relative and absolute chronologies as well as the narrative of technical development. We are now able to date the beginning of the Early Bronze Age to around 2150 BC and its end to around 1700 BC. Moreover, there is no transition between Bronze (Bz) A1 and Bronze (Bz) A2, but a complete overlap between the type objects of the two phases from 1900–1700 BC. We thus present a revised chronology of the assumed diagnostic type objects of the Early Bronze Age and recommend a radiocarbon-based view on the development of the material culture. Finally, we propose that the traditional phases Bz A1 and Bz A2 do not represent a chronological sequence, but regionally different social phenomena connected to the willingness of local actors to appropriate the new bronze technology. PMID:26488413

  19. Rewriting the Central European Early Bronze Age Chronology: Evidence from Large-Scale Radiocarbon Dating.

    PubMed

    Stockhammer, Philipp W; Massy, Ken; Knipper, Corina; Friedrich, Ronny; Kromer, Bernd; Lindauer, Susanne; Radosavljević, Jelena; Wittenborn, Fabian; Krause, Johannes

    2015-01-01

    The transition from the Neolithic to the Early Bronze Age in Central Europe has often been considered as a supra-regional uniform process, which led to the growing mastery of the new bronze technology. Since the 1920s, archaeologists have divided the Early Bronze Age into two chronological phases (Bronze A1 and A2), which were also seen as stages of technical progress. On the basis of the early radiocarbon dates from the cemetery of Singen, southern Germany, the beginning of the Early Bronze Age in Central Europe was originally dated around 2300/2200 BC and the transition to more complex casting techniques (i.e., Bronze A2) around 2000 BC. On the basis of 140 newly radiocarbon dated human remains from Final Neolithic, Early and Middle Bronze Age cemeteries south of Augsburg (Bavaria) and a re-dating of ten graves from the cemetery of Singen, we propose a significantly different dating range, which forces us to re-think the traditional relative and absolute chronologies as well as the narrative of technical development. We are now able to date the beginning of the Early Bronze Age to around 2150 BC and its end to around 1700 BC. Moreover, there is no transition between Bronze (Bz) A1 and Bronze (Bz) A2, but a complete overlap between the type objects of the two phases from 1900-1700 BC. We thus present a revised chronology of the assumed diagnostic type objects of the Early Bronze Age and recommend a radiocarbon-based view on the development of the material culture. Finally, we propose that the traditional phases Bz A1 and Bz A2 do not represent a chronological sequence, but regionally different social phenomena connected to the willingness of local actors to appropriate the new bronze technology. PMID:26488413

  20. Effectiveness of copper and bronze for zinc capture

    SciTech Connect

    Korinko, P. S.

    2012-10-15

    A series of experiments was conducted to determine the efficacy of using copper and bronze sheet and screen under high vacuum conditions to capture zinc vapor. The experiments were conducted in a parametric manner using a fixed zinc vaporization temperature (350°C) but varying the filter temperature from ambient to 550°C. Consistent with previous work, metallic zinc was deposited at low temperatures, but the deposit was non-adherent. At an intermediate temperature range (350-450°C), the deposit formed an alloy with both copper and bronze materials. At higher temperatures (> 500°C) the zinc did not deposit on the surfaces likely due to its high vapor pressure. Additional testing to optimize the zinc 'getter' chemistry and surface condition is warranted.

  1. Casting Simulation of an Austrian Bronze Age Sword Hilt

    NASA Astrophysics Data System (ADS)

    Pola, Annalisa; Mödlinger, Marianne; Piccardo, Paolo; Montesano, Lorenzo

    2015-07-01

    Bronze Age swords with a metal hilt can be considered the peak of Bronze Age casting technologies. To reconstruct the casting techniques used more than 3000 years ago, a metal hilted sword of the Schalenknauf type from Lower Austria was studied with the aid of macroscopic analyses and simulation of mold filling and casting solidification. A three-dimensional model of the hilt was created based on optical scanner measurements performed on a hilt recently discovered during archaeological excavations. Three different configurations of the gating system were considered, two on the pommel disk and one on the knob, and the effect of its location on the formation of casting defects was investigated. Three-dimensional computed tomography was used to detect internal defects, such as gas and shrinkage porosity, which were then compared with those calculated by simulation. The best match between actual and predicted hilt quality demonstrated the location of the gating system, which turned out to be on the pommel disk.

  2. Nettle as a distinct Bronze Age textile plant

    PubMed Central

    Bergfjord, C.; Mannering, U.; Frei, K. M.; Gleba, M.; Scharff, A. B.; Skals, I.; Heinemeier, J.; Nosch, M. -L; Holst, B.

    2012-01-01

    It is generally assumed that the production of plant fibre textiles in ancient Europe, especially woven textiles for clothing, was closely linked to the development of agriculture through the use of cultivated textile plants (flax, hemp). Here we present a new investigation of the 2800 year old Lusehøj Bronze Age Textile from Voldtofte, Denmark, which challenges this assumption. We show that the textile is made of imported nettle, most probably from the Kärnten-Steiermark region, an area which at the time had an otherwise established flax production. Our results thus suggest that the production of woven plant fibre textiles in Bronze Age Europe was based not only on cultivated textile plants but also on the targeted exploitation of wild plants. The Lusehøj find points to a hitherto unrecognized role of nettle as an important textile plant and suggests the need for a re-evaluation of textile production resource management in prehistoric Europe. PMID:23024858

  3. Hormonal regulation of leaf senescence in Lilium.

    PubMed

    Arrom, Laia; Munné-Bosch, Sergi

    2012-10-15

    In addition to floral senescence and longevity, the control of leaf senescence is a major factor determining the quality of several cut flowers, including Lilium, in the commercial market. To better understand the physiological process underlying leaf senescence in this species, we evaluated: (i) endogenous variation in the levels of phytohormones during leaf senescence, (ii) the effects of leaf darkening in senescence and associated changes in phytohormones, and (iii) the effects of spray applications of abscisic acid (ABA) and pyrabactin on leaf senescence. Results showed that while gibberellin 4 (GA(4)) and salicylic acid (SA) contents decreased, that of ABA increased during the progression of leaf senescence. However, dark-induced senescence increased ABA levels, but did not affect GA(4) and SA levels, which appeared to correlate more with changes in air temperature and/or photoperiod than with the induction of leaf senescence. Furthermore, spray applications of pyrabactin delayed the progression of leaf senescence in cut flowers. Thus, we conclude that (i) ABA plays a major role in the regulation of leaf senescence in Lilium, (ii) darkness promotes leaf senescence and increases ABA levels, and (iii) exogenous applications of pyrabactin inhibit leaf senescence in Lilium, therefore suggesting that it acts as an antagonist of ABA in senescing leaves of cut lily flowers. PMID:22854182

  4. Possible toxic metal exposure of prehistoric bronze workers.

    PubMed Central

    Harper, M

    1987-01-01

    An attempt has been made to assess the possible occupational exposure to arsenic, lead, and mercury during the Bronze Age. Archaeological, metallurgical, and historical evidence is combined to form a picture of the potential toxic hazards. In the case of arsenic a definite picture emerges of the effect of toxicity as a useful material is abandoned for health reasons on discovery of an acceptable alternative. Images PMID:3314977

  5. Effect of alloying elements on the physicomechanical properties of copper and tin bronze

    NASA Astrophysics Data System (ADS)

    Ri, Kh.; Komkov, V. G.; Ri, E. Kh.

    2014-09-01

    The effect of alloying elements (Al, Si, Mn, Zn, Ni, As) on the physicomechanical properties of copper and tin bronze (6 wt % Sn) is studied. These alloying elements are found to increase the hardness and the microhardness of the structural constituents of Cu- X alloys due to hardening the α solid solution and eutectoid, and this effect of alloying elements is most effective in tin bronze. Alloyed copper and tin bronze have a lower thermal conductivity and corrosion resistance as compared to plain copper and tin bronze.

  6. Tamil Chola Bronzes and Swamimalai Legacy: Metal Sources and Archaeotechnology

    NASA Astrophysics Data System (ADS)

    Srinivasan, Sharada

    2016-05-01

    This review explores the great copper alloy image casting traditions of southern India from archaeometallurgical and ethnometallurgical perspectives. The usefulness of lead isotope ratio and compositional analysis in the finger-printing and art historical study of more than 130 early historic, Pallava, Chola, later Chola, and Vijayanagara sculptures (fifth-eighteenth centuries) is highlighted, including Nataraja, Buddha, Parvati, and Rama images made of copper, leaded bronze, brass, and gilt copper. Image casting traditions at Swamimalai in Tamil Nadu are compared with artistic treatises and with the technical examination of medieval bronzes, throwing light on continuities and changes in foundry practices. Western Indian sources could be pinpointed for a couple of medieval images from lead isotope analysis. Slag and archaeometallurgical investigations suggest the exploitation of some copper and lead-silver sources in the Andhra and Karnataka regions in the early historic Satavahana period and point to probable copper sources for the medieval images in Karnataka, Tamil Nadu, and Andhra Pradesh. The general lower iron content in southern Indian bronzes perhaps renders the proximal copper-magnetite reserves of Seruvila in Sri Lanka as a less likely source. Given the lack of lead deposits in Sri Lanka, however, the match of the lead isotope signatures of a well-known Ceylonese Buddhist Tara in British Museum with a Buddha image from Nagapattinam in Tamil Nadu may underscore ties between the island nation and the southern Indian Tamil regions.

  7. Lithium vanadium bronze thin films for electrochromic applications

    SciTech Connect

    Green, M.; Pita, K.

    1997-04-01

    Thin films of fine grained polycrystalline stoichiometric vanadium pentoxide (85{percent} of bulk density) have been prepared by vacuum evaporation. These films have been made into lithium vanadium bronze, Li{sub x}V{sub 2}O{sub 5}, by inserting lithium, either electrochemically or chemically. In addition, lithium vanadium bronze thin films have been prepared by co-evaporation of Li and V{sub 2}O{sub 5}. The optical properties, absorption and refractive index, have been measured from 2000 to about 200 nm. Strong absorption arises from indirect transitions across the main gap and is {approx}2.2 eV for x=0. The variation of the energy gap up to an x value of 2 has been obtained from the absorption data and the importance of irreversible phase changes noted. High x value bronze is useful as a counter electrode material in glazings, having an energy gap of about 3 eV. There is a considerable, technologically significant, band tail in the absorption spectrum thought to arise from polaronic-type states, perhaps modified by the presence of guest species ions. The optical behavior upon lithium electrochemical insertion has also been examined. It is found that nonstoichiometry gives rise to an overall reduction in optical change per guest atom inserted. These effects are fast compared with electrochemical insertion times. {copyright} {ital 1997 American Institute of Physics.}

  8. Portable EDXRF investigation of the patinas on the Riace Bronzes

    NASA Astrophysics Data System (ADS)

    Buccolieri, Giovanni; Buccolieri, Alessandro; Donati, Paola; Marabelli, Maurizio; Castellano, Alfredo

    2015-01-01

    This paper summarizes the experimental results concerning the Energy Dispersive X-ray Fluorescence (EDXRF) analysis of patinas on two Riace Bronzes, kept in the National Archaeological Museum of Reggio Calabria (Calabria, Southern Italy). The two large Greek sculptures, famous nude bearded warriors both dated in the fifth century BC, are without a doubt, two masterpieces of inestimable historic and artistic value. EDXRF survey had the aim to determinate the chemical composition of the surface of these two bronze statues and to discriminate their different patinas. In particular, the concentration of sulphur, chlorine, tin, manganese, iron, copper, zinc and lead was determined by using a portable apparatus. Multivariate statistical analysis was carried out in order to identify possible correlations and/or differences of elemental composition among the patinas of these two statues. The information obtained made it possible to improve knowledge about the patinas of the Riace Bronzes, and this may help further studies and subsequent methods of restoration and/or of preservation of the two celebrated Greek sculptures.

  9. Effect of Thermally Softened Bronze Matrix on the Fracturing Behavior of Diamond Particles in Hybrid Sprayed Bronze/Diamond Composite

    NASA Astrophysics Data System (ADS)

    Na, Hyuntaek; Bae, Gyuyeol; Kang, Kicheol; Kim, Hyungjun; Kim, Jay-Jung; Lee, Changhee

    2010-09-01

    In our previous study (Na et al., Compos Sci Technol 69:463-468, 2009), optimized thickness of protective nickel film was proposed for smaller diamond feedstock to obtain reduced impact stress and uniform flight behavior of particles during kinetic (or cold) spraying. However, in this study, nickel-coated diamond particles were severely fractured with increasing particle size due to high kinetic energy. Hence, an innovative hybrid spraying technique (a combination of kinetic and thermal spraying) was introduced to embed relatively large diamond particles into the bronze matrix. Size distributions of the diamond particles in the composite coatings were analyzed by scanning electron microscopy, an electron probe micro analyzer, and image analysis methods. In addition, impact behaviors of diamond particles in kinetic and hybrid gas flows were simulated through finite element analysis (ABAQUS/Explicit 6.7-2). Diamond fracturing was significantly minimized by the reduced impact energy afforded by the thermally softened bronze matrix through hybrid spraying.

  10. Resource quality affects weapon and testis size and the ability of these traits to respond to selection in the leaf-footed cactus bug, Narnia femorata.

    PubMed

    Sasson, Daniel A; Munoz, Patricio R; Gezan, Salvador A; Miller, Christine W

    2016-04-01

    The size of weapons and testes can be central to male reproductive success. Yet, the expression of these traits is often extremely variable. Studies are needed that take a more complete organism perspective, investigating the sources of variation in both traits simultaneously and using developmental conditions that mimic those in nature. In this study, we investigated the components of variation in weapon and testis sizes using the leaf-footed cactus bug, Narnia femorata (Hemiptera: Coreidae) on three natural developmental diets. We show that the developmental diet has profound effects on both weapon and testis expression and scaling. Intriguingly, males in the medium-quality diet express large weapons but have relatively tiny testes, suggesting complex allocation decisions. We also find that heritability, evolvability, and additive genetic variation are highest in the high-quality diet for testis and body mass. This result suggests that these traits may have an enhanced ability to respond to selection during a small window of time each year when this diet is available. Taken together, these results illustrate that normal, seasonal fluctuations in the nutritional environment may play a large role in the expression of sexually selected traits and the ability of these traits to respond to selection. PMID:27066225

  11. Climate change conditions (elevated CO2 and temperature) and UV-B radiation affect grapevine (Vitis vinifera cv. Tempranillo) leaf carbon assimilation, altering fruit ripening rates.

    PubMed

    Martínez-Lüscher, J; Morales, F; Sánchez-Díaz, M; Delrot, S; Aguirreolea, J; Gomès, E; Pascual, I

    2015-07-01

    The increase in grape berry ripening rates associated to climate change is a growing concern for wine makers as it rises the alcohol content of the wine. The present work studied the combined effects of elevated CO2, temperature and UV-B radiation on leaf physiology and berry ripening rates. Three doses of UV-B: 0, 5.98, 9.66 kJm(-2)d(-1), and two CO2-temperature regimes: ambient CO2-24/14 °C (day/night) (current situation) and 700 ppm CO2-28/18 °C (climate change) were imposed to grapevine fruit-bearing cuttings from fruit set to maturity under greenhouse-controlled conditions. Photosynthetic performance was always higher under climate change conditions. High levels of UV-B radiation down regulated carbon fixation rates. A transient recovery took place at veraison, through the accumulation of flavonols and the increase of antioxidant enzyme activities. Interacting effects between UV-B and CO2-temperature regimes were observed for the lipid peroxidation, which suggests that UV-B may contribute to palliate the signs of oxidative damage induced under elevated CO2-temperature. Photosynthetic and ripening rates were correlated. Thereby, the hastening effect of climate change conditions on ripening, associated to higher rates of carbon fixation, was attenuated by UV-B radiation. PMID:26025530

  12. Extraction of bioactive compounds and free radical scavenging activity of purple basil (Ocimum basilicum L.) leaf extracts as affected by temperature and time.

    PubMed

    Pedro, Alessandra C; Moreira, Fernanda; Granato, Daniel; Rosso, Neiva D

    2016-05-13

    In the current study, response surface methodology (RSM) was used to assess the effects of extraction time and temperature on the content of bioactive compounds and antioxidant activity of purple basil leaf (Ocimum basilicum L.) extracts. The stability of anthocyanins in relation to temperature, light and copigmentation was also studied. The highest anthocyanin content was 67.40 mg/100 g extracted at 30 °C and 60 min. The degradation of anthocyanins with varying temperatures and in the presence of light followed a first-order kinetics and the activation energy was 44.95 kJ/mol. All the extracts exposed to light showed similar half-lives. The extracts protected from light, in the presence of copigments, showed an increase in half-life from 152.67 h for the control to 856.49 and 923.17 h for extract in the presence of gallic acid and phytic acid, respectively. These results clearly indicate that purple basil is a potential source of stable bioactive compounds. PMID:27192193

  13. Mutation of the Light-Induced Yellow Leaf 1 Gene, Which Encodes a Geranylgeranyl Reductase, Affects Chlorophyll Biosynthesis and Light Sensitivity in Rice

    PubMed Central

    Yuan, Yuan; Zhu, Jinyan; Wang, Man; Yuan, Fuhai; Wu, Shujun; Wang, Zhiqin; Yi, Chuandeng; Xu, Tinghua; Ryom, MyongChol; Gu, Minghong; Liang, Guohua

    2013-01-01

    Chlorophylls (Chls) are crucial for capturing light energy for photosynthesis. Although several genes responsible for Chl biosynthesis were characterized in rice (Oryza sativa), the genetic properties of the hydrogenating enzyme involved in the final step of Chl synthesis remain unknown. In this study, we characterized a rice light-induced yellow leaf 1-1 (lyl1-1) mutant that is hypersensitive to high-light and defective in the Chl synthesis. Light-shading experiment suggested that the yellowing of lyl1-1 is light-induced. Map-based cloning of LYL1 revealed that it encodes a geranylgeranyl reductase. The mutation of LYL1 led to the majority of Chl molecules are conjugated with an unsaturated geranylgeraniol side chain. LYL1 is the firstly defined gene involved in the reduction step from Chl-geranylgeranylated (ChlGG) and geranylgeranyl pyrophosphate (GGPP) to Chl-phytol (ChlPhy) and phytyl pyrophosphate (PPP) in rice. LYL1 can be induced by light and suppressed by darkness which is consistent with its potential biological functions. Additionally, the lyl1-1 mutant suffered from severe photooxidative damage and displayed a drastic reduction in the levels of α-tocopherol and photosynthetic proteins. We concluded that LYL1 also plays an important role in response to high-light in rice. PMID:24058671

  14. Association of tomato leaf curl Sudan virus with leaf curl disease of tomato in Jeddah, Saudi Arabia.

    PubMed

    Sohrab, Sayed Sartaj; Yasir, Muhammad; El-Kafrawy, Sherif Ali; Abbas, Ayman T; Mousa, Magdi Ali Ahmed; Bakhashwain, Ahmed A

    2016-06-01

    Tomato is an important vegetable crop and its production is adversely affected by leaf curl disease caused by begomovirus. Leaf curl disease is a serious concern for tomato crops caused by begomovirus in Jeddah, Kingdom of Saudi Arabia. Tomato leaf curl disease has been shown to be mainly caused either by tomato leaf curl Sudan virus or tomato yellow leaf curl virus as well as tomato leaf curl Oman virus. Many tomato plants infected with monopartite begomoviruses were also found to harbor a symptom enhancing betasatellites. Here we report the association of tomato leaf curl Sudan virus causing leaf curl disease of tomato in Jeddah, Kingdom of Saudi Arabia. The complete genome sequence analysis showed highest (99.9 %) identity with tomato leaf curl Sudan virus causing leaf curl disease in Arabian Peninsula. In phylogenetic relationships analysis, the identified virus formed closest cluster with tomato leaf curl Sudan virus. In recombination analysis study, the major parent was identified as tomato leaf curl Sudan virus. Findings of this study strongly supports the associated virus is a variant of tomato leaf curl Sudan virus causing disease in Sudan, Yemen and Arabian Peninsula. The betasatellites sequence analysis showed highest identity (99.8 %) with tomato leaf curl betasatellites-Amaranthus-Jeddah. The phylogenetic analysis result based on betasatellites formed closed cluster with tomato yellow leaf curl Oman betasatellites. The importance of these findings and occurrence of begomovirus in new geographic regions causing leaf curl disease of tomato in Jeddah, Kingdom of Saudi Arabia are discussed. PMID:27366765

  15. Earthquake and the Catastrophic End of the Late Bronze Age in the Eastern Mediterranean

    NASA Astrophysics Data System (ADS)

    Nur, A.

    2009-04-01

    The reasons for the catastrophic and wide spread political as well as physical collapse in the Aegean and Eastern Mediterranean areas that define the end of the Bronze age ca. 1225 BC to 1175 BC remain a major enigma. It has been attributed by historian to attacks by outsiders with the most favored group being the (enigmatic) so-called sea people. Unfortunately there is no real evidence for this. However combined geological, geophysical and archaeological evidence suggests that earthquakes may have played a key role in this extraordinary collapse during the late 13th and early 12th centuries . Based on the instrumentally recorded earthquakes occurring in the Aegean and Eastern Mediterranean region during the 20th century, several events that have clear historical information, and the geography of seismically active faults it is obvious that numerous earthquakes of magnitude 6·5 or greater (enough to destroy modern buildings, let alone those of antiquity) occurred here frequently in the past. Furthermore major earthquakes often occur in this region in groups, known as ‘‘sequences'' or ‘‘storms'', in which one large quake is followed days, months, or a few years later by others elsewhere on the plate boundary fault lines. When a map of the areas in the Aegean and Eastern Mediterranean region shaken by 20th century  earthquakes of magnitude 6·5 and greater and with an intensity of VII or greater is overlaid on Robert Drews' map of sites destroyed in these same regions during the so-called ‘‘Catastrophe'' near the end of the Late Bronze Age, it is readily apparent that virtually all of these LBA sites lie within the affected (‘‘high-shaking'') areas. This would suggest that a major ‘‘earthquake storm'' may have occurred in the Late Bronze Age Aegean and Eastern Mediterranean during the years 1225-1175 . This ‘‘storm'' may have interacted with societal, political and economic forces at work in these areas c. 1200  and

  16. 48 CFR 252.216-7000 - Economic price adjustment-basic steel, aluminum, brass, bronze, or copper mill products.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...-basic steel, aluminum, brass, bronze, or copper mill products. 252.216-7000 Section 252.216-7000 Federal... adjustment—basic steel, aluminum, brass, bronze, or copper mill products. As prescribed in 216.203-4-70(a), use the following clause: Economic Price Adjustment—Basic Steel, Aluminum, Brass, Bronze, or...

  17. 48 CFR 252.216-7000 - Economic price adjustment-basic steel, aluminum, brass, bronze, or copper mill products.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...-basic steel, aluminum, brass, bronze, or copper mill products. 252.216-7000 Section 252.216-7000 Federal... adjustment—basic steel, aluminum, brass, bronze, or copper mill products. As prescribed in 216.203-4-70(a), use the following clause: Economic Price Adjustment—Basic Steel, Aluminum, Brass, Bronze, or...

  18. 48 CFR 252.216-7007 - Economic price adjustment-basic steel, aluminum, brass, bronze, or copper mill products...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...-basic steel, aluminum, brass, bronze, or copper mill products-representation. 252.216-7007 Section 252....216-7007 Economic price adjustment—basic steel, aluminum, brass, bronze, or copper mill products... Steel, Aluminum, Brass, Bronze, or Copper Mill Products—Representation (MAR 2012) (a) Definitions....

  19. 48 CFR 252.216-7007 - Economic price adjustment-basic steel, aluminum, brass, bronze, or copper mill products...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...-basic steel, aluminum, brass, bronze, or copper mill products-representation. 252.216-7007 Section 252....216-7007 Economic price adjustment—basic steel, aluminum, brass, bronze, or copper mill products... Steel, Aluminum, Brass, Bronze, or Copper Mill Products—Representation (MAR 2012) (a) Definitions....

  20. 48 CFR 252.216-7000 - Economic price adjustment-basic steel, aluminum, brass, bronze, or copper mill products.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...-basic steel, aluminum, brass, bronze, or copper mill products. 252.216-7000 Section 252.216-7000 Federal... adjustment—basic steel, aluminum, brass, bronze, or copper mill products. As prescribed in 216.203-4-70(a)(1), use the following clause: Economic Price Adjustment—Basic Steel, Aluminum, Brass, Bronze, or...

  1. 48 CFR 252.216-7007 - Economic price adjustment-basic steel, aluminum, brass, bronze, or copper mill products...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...-basic steel, aluminum, brass, bronze, or copper mill products-representation. 252.216-7007 Section 252....216-7007 Economic price adjustment—basic steel, aluminum, brass, bronze, or copper mill products... Steel, Aluminum, Brass, Bronze, or Copper Mill Products—Representation (MAR 2012) (a) Definitions....

  2. 48 CFR 252.216-7000 - Economic price adjustment-basic steel, aluminum, brass, bronze, or copper mill products.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...-basic steel, aluminum, brass, bronze, or copper mill products. 252.216-7000 Section 252.216-7000 Federal... adjustment—basic steel, aluminum, brass, bronze, or copper mill products. As prescribed in 216.203-4-70(a)(1), use the following clause: Economic Price Adjustment—Basic Steel, Aluminum, Brass, Bronze, or...

  3. 48 CFR 252.216-7000 - Economic price adjustment-basic steel, aluminum, brass, bronze, or copper mill products.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...-basic steel, aluminum, brass, bronze, or copper mill products. 252.216-7000 Section 252.216-7000 Federal... adjustment—basic steel, aluminum, brass, bronze, or copper mill products. As prescribed in 216.203-4-70(a)(1), use the following clause: Economic Price Adjustment—Basic Steel, Aluminum, Brass, Bronze, or...

  4. 7 CFR 51.1814 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false U.S. No. 1 Bronze. 51.1814 Section 51.1814 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Florida Tangerines Grades § 51.1814 U.S. No. 1 Bronze. The requirements for...

  5. 7 CFR 51.684 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false U.S. No. 1 Bronze. 51.684 Section 51.684 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing..., California, and Arizona) Grades § 51.684 U.S. No. 1 Bronze. The requirements for this grade are the same...

  6. 7 CFR 51.684 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false U.S. No. 1 Bronze. 51.684 Section 51.684 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing....684 U.S. No. 1 Bronze. The requirements for this grade are the same as for U.S. No 1 except that...

  7. 7 CFR 51.754 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false U.S. No. 1 Bronze. 51.754 Section 51.754 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Florida Grapefruit Grades § 51.754 U.S. No. 1 Bronze. The requirements for...

  8. 7 CFR 51.754 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false U.S. No. 1 Bronze. 51.754 Section 51.754 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing.... 1 Bronze. The requirements for this grade are the same as for U.S. No. 1 except that at least...

  9. 7 CFR 51.684 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false U.S. No. 1 Bronze. 51.684 Section 51.684 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing....684 U.S. No. 1 Bronze. The requirements for this grade are the same as for U.S. No 1 except that...

  10. 7 CFR 51.623 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false U.S. No. 1 Bronze. 51.623 Section 51.623 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... § 51.623 U.S. No. 1 Bronze. The requirements for this grade are the same as for U.S. No. 1 except...

  11. 7 CFR 51.1814 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false U.S. No. 1 Bronze. 51.1814 Section 51.1814 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Florida Tangerines Grades § 51.1814 U.S. No. 1 Bronze. The requirements for...

  12. 7 CFR 51.684 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false U.S. No. 1 Bronze. 51.684 Section 51.684 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing....684 U.S. No. 1 Bronze. The requirements for this grade are the same as for U.S. No 1 except that...

  13. 7 CFR 51.623 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false U.S. No. 1 Bronze. 51.623 Section 51.623 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... § 51.623 U.S. No. 1 Bronze. The requirements for this grade are the same as for U.S. No. 1 except...

  14. 7 CFR 51.623 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false U.S. No. 1 Bronze. 51.623 Section 51.623 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Florida, California, and Arizona) Grades § 51.623 U.S. No. 1 Bronze. The requirements for this grade...

  15. 7 CFR 51.623 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false U.S. No. 1 Bronze. 51.623 Section 51.623 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... § 51.623 U.S. No. 1 Bronze. The requirements for this grade are the same as for U.S. No. 1 except...

  16. 7 CFR 51.1145 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false U.S. No. 1 Bronze. 51.1145 Section 51.1145 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing....1145 U.S. No. 1 Bronze. The requirements for this grade are the same as for U.S. No. 1 except at...

  17. 7 CFR 51.623 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false U.S. No. 1 Bronze. 51.623 Section 51.623 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Florida, California, and Arizona) Grades § 51.623 U.S. No. 1 Bronze. The requirements for this grade...

  18. 7 CFR 51.1145 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false U.S. No. 1 Bronze. 51.1145 Section 51.1145 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing....1145 U.S. No. 1 Bronze. The requirements for this grade are the same as for U.S. No. 1 except at...

  19. 7 CFR 51.1145 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false U.S. No. 1 Bronze. 51.1145 Section 51.1145 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Florida Oranges and Tangelos Grades § 51.1145 U.S. No. 1 Bronze. The...

  20. 7 CFR 51.1814 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false U.S. No. 1 Bronze. 51.1814 Section 51.1814 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Florida Tangerines Grades § 51.1814 U.S. No. 1 Bronze. The requirements for...

  1. 7 CFR 51.1814 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 2 2014-01-01 2014-01-01 false U.S. No. 1 Bronze. 51.1814 Section 51.1814 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing.... 1 Bronze. The requirements for this grade are the same as for U.S. No. 1 except that at least...

  2. 7 CFR 51.754 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false U.S. No. 1 Bronze. 51.754 Section 51.754 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Florida Grapefruit Grades § 51.754 U.S. No. 1 Bronze. The requirements for...

  3. 7 CFR 51.754 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false U.S. No. 1 Bronze. 51.754 Section 51.754 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing.... 1 Bronze. The requirements for this grade are the same as for U.S. No. 1 except that at least...

  4. 7 CFR 51.754 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 2 2012-01-01 2012-01-01 false U.S. No. 1 Bronze. 51.754 Section 51.754 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Florida Grapefruit Grades § 51.754 U.S. No. 1 Bronze. The requirements for...

  5. 7 CFR 51.684 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false U.S. No. 1 Bronze. 51.684 Section 51.684 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing..., California, and Arizona) Grades § 51.684 U.S. No. 1 Bronze. The requirements for this grade are the same...

  6. 7 CFR 51.1814 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 2 2013-01-01 2013-01-01 false U.S. No. 1 Bronze. 51.1814 Section 51.1814 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing.... 1 Bronze. The requirements for this grade are the same as for U.S. No. 1 except that at least...

  7. 7 CFR 51.1145 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false U.S. No. 1 Bronze. 51.1145 Section 51.1145 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Florida Oranges and Tangelos Grades § 51.1145 U.S. No. 1 Bronze. The...

  8. 7 CFR 51.1145 - U.S. No. 1 Bronze.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false U.S. No. 1 Bronze. 51.1145 Section 51.1145 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Standards for Grades of Florida Oranges and Tangelos Grades § 51.1145 U.S. No. 1 Bronze. The...

  9. Metallography and microstructure interpretation of some archaeological tin bronze vessels from Iran

    SciTech Connect

    Oudbashi, Omid; Davami, Parviz

    2014-11-15

    Archaeological excavations in western Iran have recently revealed a significant Luristan Bronzes collection from Sangtarashan archaeological site. The site and its bronze collection are dated to Iron Age II/III of western Iran (10th–7th century BC) according to archaeological research. Alloy composition, microstructure and manufacturing technique of some sheet metal vessels are determined to reveal metallurgical processes in western Iran in the first millennium BC. Experimental analyses were carried out using Scanning Electron Microscopy–Energy Dispersive X-ray Spectroscopy and Optical Microscopy/Metallography methods. The results allowed reconstructing the manufacturing process of bronze vessels in Luristan. It proved that the samples have been manufactured with a binary copper–tin alloy with a variable tin content that may relates to the application of an uncontrolled procedure to make bronze alloy (e.g. co-smelting or cementation). The presence of elongated copper sulphide inclusions showed probable use of copper sulphide ores for metal production and smelting. Based on metallographic studies, a cycle of cold working and annealing was used to shape the bronze vessels. - Highlights: • Sangtarashan vessels are made by variable Cu-Sn alloys with some impurities. • Various compositions occurred due to applying uncontrolled smelting methods. • The microstructure represents thermo-mechanical process to shape bronze vessels. • In one case, the annealing didn’t remove the eutectoid remaining from casting. • The characteristics of the bronzes are similar to other Iron Age Luristan Bronzes.

  10. Factors affecting adventitious regeneration from in vitro leaf explants of 'Improved French' plum, the most important dried plum cultivar in the USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An adventitious shoot regeneration protocol from leaves of the most important dried plum cultivar in the U.S., 'Improved French', has been established. Factors affecting regeneration were studied, and relatively high percentages have been obtained. The proliferation medium were shoots, used as the...

  11. Metallurgical and Chemical Characterization of Bronze Remains Found at the Houhe Site in Shanxi Province, China

    NASA Astrophysics Data System (ADS)

    Mu, D.; Nan, P. H.; Wang, J. Y.; Song, G. D.; Luo, W. G.

    2015-07-01

    This study attempts to determine the metallurgical and chemical characteristics of Chinese bronze artifacts from the early Iron Age by taking the bronze artifacts from the Houhe site as an example. The bronze artifacts included vessels, buckles, mirrors, and bells. Elemental compositions of 10 Chinese bronze artifacts from the Houhe site were determined by an x-ray fluorescence system. Microstructures were observed by a polarizing microscope. Most of the artifacts were cast and lacked external evidence of secondary processing. The copper content of the vessels is higher than the other samples, and the copper content of buckles is the lowest. High tin content is a distinctive characteristic of the mirrors. Through comparisons, bells show a decline in the content of copper from the Western Zhou dynasty to the early Han dynasty, and the content of lead increased over time. Combined with historical studies, the findings show that there may have been industrial standards for bronze production during the Han dynasty.

  12. The study of bronze statuettes with the help of neutron-imaging techniques.

    PubMed

    Van Langh, R; Lehmann, E; Hartmann, S; Kaestner, A; Scholten, F

    2009-12-01

    Until recently fabrication techniques of Renaissance bronzes have been studied only with the naked eye, microscopically, videoscopically and with X-radiography. These techniques provide information on production techniques, yet much important detail remains unclear. As part of an interdisciplinary study of Renaissance bronzes undertaken by the Rijksmuseum Amsterdam, neutron-imaging techniques have been applied with the aim of obtaining a better understanding of bronze workmanship during the Renaissance period. Therefore, an explanation of the fabrication techniques is given to better understand the data collected by these neutron-imaging techniques. The data was used for tomography studies, which reveal hidden aspects that could not at all or scarcely be seen using X-radiography. For this specific study, the representative bronze 'Hercules Pomarius' of Willem van Tetrode (ca 1520-1588) has been examined, along with 20 other Renaissance bronzes from the Rijksmuseum collection. PMID:19756545

  13. Unified approach for determining tetragonal tungsten bronze crystal structures.

    PubMed

    Smirnov, M; Saint-Grégoire, P

    2014-05-01

    Tetragonal tungsten bronze (TTB) oxides are one of the most important classes of ferroelectrics. Many of these framework structures undergo ferroelastic transformations related to octahedron tilting deformations. Such tilting deformations are closely related to the rigid unit modes (RUMs). This paper discusses the whole set of RUMs in an ideal TTB lattice and possible crystal structures which can emerge owing to the condensation of some of them. Analysis of available experimental data for the TTB-like niobates lends credence to the obtained theoretical predictions. PMID:24815976

  14. Investigation of laser cleaning on bronze cultural relics

    NASA Astrophysics Data System (ADS)

    Ling, Xiulan; Wang, Gao; Zhang, Chen

    2016-05-01

    The effects of laser cleaning on the corrosion layers of bronze cultural relics were studied using a pulsed fiber laser. The laser cleaning threshold value of the corrosion layers was obtained. It was found that the corrosion layer was removed successfully by employing a laser fluence value of 0.32 J cm-2 and scanning for three times. To obtain experimental evidence, laser con-focal scanning microscopy, scanning electron microscopy (SEM), energy dispersive x-ray spectroscopy (EDS), laser induced breakdown spectroscopy (LIBS) and laser Raman spectroscopy were employed to investigate the cleaning efficiency of corrosion layers on specimens.

  15. Late Bronze Age glass production at Qantir-Piramesses, Egypt.

    PubMed

    Rehren, Thilo; Pusch, Edgar B

    2005-06-17

    It has been uncertain whether the glass produced during the Late Bronze Age (LBA) originated in Egypt or Mesopotamia. Here we present evidence for the production of glass from its raw materials in the eastern Nile Delta during the LBA. Glass was made in workshops that were separate from where the production of objects took place. The initial melting of the raw materials to semi-finished glass was done at temperatures of 900 degrees to 950 degrees C, followed by coloration and ingot production at 1000 degrees to 1100 degrees C. PMID:15961663

  16. Analysis of selective laser cleaning of patina on bronze coins

    NASA Astrophysics Data System (ADS)

    Buccolieri, G.; Nassisi, V.; Torrisi, L.; Buccolieri, A.; Castellano, A.; Di Giulio, M.; Giuffreda, E.; Delle Side, D.; Velardi, L.

    2014-04-01

    The patina, is the result of a large number of chemical, electrochemical and physical processes which occur spontaneously during interaction of metal surfaces with the environment. In this work we want to analyze and remove the patina in artefacts, exposed to atmosphere for various decades. Here, experimental results about the laser cleaning of bronze coins by KrF (248 nm) and Nd:YAG (532 nm) lasers are reported. Both laser wavelengths were efficient to reduce the chlorine concentration on the surface of the coins more than 80 %, as demonstrated by Energy Dispersive X-Ray Fluorescence analyses.

  17. Leaf litter decomposition in three Adirondack lakes

    SciTech Connect

    Francis, A.J.; Quinby, H.L.; Hendrey, G.R.; Hoogendyk, C.G.

    1983-04-01

    Decomposition of terrestrial leaf litter in three Adirondack lakes with water pH values approximately 5, 6, and 7 was studied. Litter bags containing leaves of American beech, sugar maple, red maple, leather leaf, and red spruce were placed in the lakes. Samples were removed periodically over a 3-year period and analyzed for loss in weight, changes in leaf surface area, carbon, nitrogen, and bacterial populations. The rate of decomposition of litter depended on the leaf species tested as well as on the lake water in which they were incubated. Of the five leaf species tested, red maple decomposed much faster and red spruce more slowly, i.e., red maple > sugar maple > beech > leather leaf > red spruce. Further, the data indicated that the rate of decomposition of the leaves differed among the lakes in the order Woods (pH approx. 5) < Sagamore (pH approx. 6) < Panther (pH approx. 7), and that the microbial colonization of some leaf species was affected. Accumulations of leaf litter in acid lakes due to reduction in microbial decomposition may affect nutrient recycling in lake ecosystems. 8 references, 4 tables.

  18. Environmental roots of the late bronze age crisis.

    PubMed

    Kaniewski, David; Van Campo, Elise; Guiot, Joël; Le Burel, Sabine; Otto, Thierry; Baeteman, Cecile

    2013-01-01

    The Late Bronze Age world of the Eastern Mediterranean, a rich linkage of Aegean, Egyptian, Syro-Palestinian, and Hittite civilizations, collapsed famously 3200 years ago and has remained one of the mysteries of the ancient world since the event's retrieval began in the late 19(th) century AD/CE. Iconic Egyptian bas-reliefs and graphic hieroglyphic and cuneiform texts portray the proximate cause of the collapse as the invasions of the "Peoples-of-the-Sea" at the Nile Delta, the Turkish coast, and down into the heartlands of Syria and Palestine where armies clashed, famine-ravaged cities abandoned, and countrysides depopulated. Here we report palaeoclimate data from Cyprus for the Late Bronze Age crisis, alongside a radiocarbon-based chronology integrating both archaeological and palaeoclimate proxies, which reveal the effects of abrupt climate change-driven famine and causal linkage with the Sea People invasions in Cyprus and Syria. The statistical analysis of proximate and ultimate features of the sequential collapse reveals the relationships of climate-driven famine, sea-borne-invasion, region-wide warfare, and politico-economic collapse, in whose wake new societies and new ideologies were created. PMID:23967146

  19. Environmental Roots of the Late Bronze Age Crisis

    PubMed Central

    Kaniewski, David; Van Campo, Elise; Guiot, Joël; Le Burel, Sabine; Otto, Thierry; Baeteman, Cecile

    2013-01-01

    The Late Bronze Age world of the Eastern Mediterranean, a rich linkage of Aegean, Egyptian, Syro-Palestinian, and Hittite civilizations, collapsed famously 3200 years ago and has remained one of the mysteries of the ancient world since the event’s retrieval began in the late 19th century AD/CE. Iconic Egyptian bas-reliefs and graphic hieroglyphic and cuneiform texts portray the proximate cause of the collapse as the invasions of the “Peoples-of-the-Sea” at the Nile Delta, the Turkish coast, and down into the heartlands of Syria and Palestine where armies clashed, famine-ravaged cities abandoned, and countrysides depopulated. Here we report palaeoclimate data from Cyprus for the Late Bronze Age crisis, alongside a radiocarbon-based chronology integrating both archaeological and palaeoclimate proxies, which reveal the effects of abrupt climate change-driven famine and causal linkage with the Sea People invasions in Cyprus and Syria. The statistical analysis of proximate and ultimate features of the sequential collapse reveals the relationships of climate-driven famine, sea-borne-invasion, region-wide warfare, and politico-economic collapse, in whose wake new societies and new ideologies were created. PMID:23967146

  20. Manual HVOF thermal spray repair of nickel aluminum bronze castings

    SciTech Connect

    Brenna, R.T.; McCaw, R.L.; Pugh, J.L.

    1994-12-31

    Manual high velocity oxyfuel (HVOF) thermal spray repairs were accomplished on a large nickel aluminum bronze propeller castings. The repairs were done on three different configurations of surface defects of up to 100 square inches and as deep as 90 mils. Nickel aluminum bronze alloy powder, sieve sized for the HVOF process, was sprayed. High quality, high coating density, repairs were achieved even on porous areas of the castings. Prior to performance of the repairs, a procedure was qualified in accordance with MIL-STD-1687 and a mock-up simulating the repair was produced. After HVOF spraying of the mock-up, the sprayed surface was sanded, milled, and drilled to determine how finishing of the actual castings would be done. After successful procedure qualification, the HVOF equipment was moved to the job site, metal masking was devised for the spray areas and grit blasting and manual HVOF spraying was done. Results of HVOF coating chemical analyses, bend tests, coating tensile bond strength tests, coating microscopic examinations, and mock-up evaluations are reported along with the spray procedures and techniques used in the repairs.

  1. Chromatic instabilities in cesium-doped tungsten bronze nanoparticles

    SciTech Connect

    Adachi, Kenji Ota, Yosuke; Tanaka, Hiroyuki; Okada, Mika; Oshimura, Nobumitsu; Tofuku, Atsushi

    2013-11-21

    Nanoparticles of alkali-doped tungsten bronzes are an excellent near-infrared shielding material, but exhibit slight chromatic instabilities typically upon applications of strong ultra-violet light or heating in humid environment, which acts detrimentally to long-life commercial applications. Origin of the chromatic instabilities in cesium-doped tungsten bronze has been investigated, and it has been found that the coloration and bleaching processes comprised electronic exchanges which accelerate or depress the polaron excitation and the localized surface plasmon resonance. Coloration on UV illumination is evidenced by electron diffraction as due to the formation of H{sub x}WO{sub 3}, which is considered to take place in the surface Cs-deficient WO{sub 3} region via the double charge injection mechanism. On the other hand, bleaching on heating in air and in humid environment is shown to accompany the extraction of Cs and electrons from Cs{sub 0.33}WO{sub 3} by X-ray photoelectron spectroscopy and X-ray diffraction analysis and is concluded to be an oxidation of Cs{sub 0.33}WO{sub 3} on the particle surface.

  2. Adult nutrition, but not inbreeding, affects male primary sexual traits in the leaf-footed cactus bug Narnia femorata (Hemiptera: Coreidae).

    PubMed

    Joseph, Paul N; Sasson, Daniel A; Allen, Pablo E; Somjee, Ummat; Miller, Christine W

    2016-07-01

    Adverse conditions may be the norm rather than the exception in natural populations. Many populations experience poor nutrition on a seasonal basis. Further, brief interludes of inbreeding can be common as population density fluctuates and because of habitat fragmentation. Here, we investigated the effects of poor nutrition and inbreeding on traits that can be very important to reproductive success and fitness in males: testes mass, sperm concentration, and sperm viability. Our study species was Narnia femorata, a species introduced to north-central Florida in the 1950s. This species encounters regular, seasonal changes in diet that can have profound phenotypic effects on morphology and behavior. We generated inbred and outbred individuals through a single generation of full-sibling mating or outcrossing, respectively. All juveniles were provided a natural, high-quality diet of Opuntia humifusa cactus cladode with fruit until they reached adulthood. New adult males were put on a high- or low-quality diet for at least 21 days before measurements were taken. As expected, the low-quality diet led to significantly decreased testes mass in both inbred and outbred males, although there were surprisingly no detectable effects on sperm traits. We did not find evidence that inbreeding affected testes mass, sperm concentration, and sperm viability. Our results highlight the immediate and overwhelming effects of nutrition on testes mass, while suggesting that a single generation of inbreeding might not be detrimental for primary sexual traits in this particular population. PMID:27547313

  3. History of a Bronze Age tell and its environment

    NASA Astrophysics Data System (ADS)

    Kovács, Gabriella; Füleky, György; Vicze, Magdolna

    2016-04-01

    Százhalombatta-Földvár is the most excessively researched Bronze Age tell site in Hungary. Parallel to the investigation of the settlement structure and activity patterns the changes of the landscape and the effect of human alteration is also studied. Significant changes of the landscape can be detected from the Bronze Age until the recent natural and cultural heritage protection of the area. Archaeological, soil analytical and thin section soil micromorphological methods are used to reconstruct the past 4000 years of the tell and its immediate surroundings. Prior to the Bronze Age the area was covered by forest vegetation, so the initial settling could only be realised after deforestation (2000 BC). The result of the soil corings and the prepared soil thin sections are solid proves of this action. It also became evident that at some areas - so far it seems that at locales where house floors were laid for the very first time - even the topsoil was removed so intensively that only the B horizon of the relict forest soil can be found. This observation needs to be further tested outside the habitation area to define the horizontal extension of the forest clearance and the topsoil removal. The northern side of the settlement is bordered by a natural erosion gully. At 2000 BC it was just a natural depression, but by 1500 BC it was deepened to serve as a fortification ditch. Around 1200 BC the ditch started to be filled in and by 1000 BC it was refilled to such an extent that its surface was utilised again. At about 600 BC (Late Iron Age) a smaller inner rampart was erected on the southern side of the ditch for inner separation. Not much is known about the Roman period of this area (200 AD) but the remnants of a watchtower indicate their presence. During the 18th century AD the area was used for grape cultivation and later for hobby gardens up until the protection of the area in the late 20th century. Since then species of the original vegetation started to grow back

  4. Effect of Hydrogen Plasma on Model Corrosion Layers of Bronze

    NASA Astrophysics Data System (ADS)

    Fojtíková, P.; Sázavská, V.; Mika, F.; Krčma, F.

    2016-05-01

    Our work is about plasmachemical reduction of model corrosion layers. The model corrosion layers were produced on bronze samples with size of 10 × 10 × 5 mm3, containing Cu and Sn. Concentrated hydrochloric acid was used as a corrosive environment. The application of reduction process in low-pressure low-temperature hydrogen plasma followed. A quartz cylindrical reactor with two outer copper electrodes was used. Plasma discharge was generated in pure hydrogen by a RF generator. Each corroded sample was treated in different conditions (supplied power and a continual or pulsed regime with a variable duty cycle mode). Process monitoring was ensured by optical emission spectroscopy. After treatment, samples were analyzed by SEM and EDX.

  5. Microstructure characterization of hypereutectoid aluminium bronze composite coating

    NASA Astrophysics Data System (ADS)

    Kucita, P.; Wang, S. C.; Li, W. S.; Cook, R. B.; Starink, M. J.

    2015-10-01

    Hypereutectoid aluminium bronze coating was deposited onto an E.N. 10503 steel substrate using plasma transferred arc welding (PTA). Microstructure characterisation of the coating and a section near the steel substrate joint was carried out using SEM, EBSD, EDS in conjunction with XRD and depth-sensing nano-indentation. The constituent phases in the coating were identified as: martensitic Cu3Al β1' phase, solid solution of Al in Cu α phase and the intermetallic Fe3Al κ1 phase. The region near the steel substrate was characterised by high hardness, large grains and presence of Cu precipitates. No cracks were observed in this region. The coating has high hardness of 4.9GPa and Young's modulus of 121.7GPa. This is attributed to homogeneous distribution of sub microns size Fe3Al intermetallic phase. The implications of the coating to the engineering application of sheet metal forming are discussed.

  6. Coloration and structure of Taiwanese bronze scarab (Anomala expansa)

    NASA Astrophysics Data System (ADS)

    Wu, Min-Nan; Chen, Chien-Yen; Pan, Wei

    2015-12-01

    The structure and optical properties of the elytra of Taiwanese bronze scarabs (Anomala expansa) were investigated. The elytron is composed by a scale-like texture on the surface and a repeated bi-layers underneath. The reflectivity spectrum shows iridescence that the peaks shifts from yellow to green color regions as long as the incident angle (θ) increases. A shoulder peak at 600 nm (θ = 20o) is absent after gently scraping the surface, which indicates that the yellow color is contributed by the scale-like texture. The remaining peak at 550 nm (θ = 20o) in the spectrum resembles the simulated spectrum by assuming the refractive index of n = 1.54 and n = 1 for the adjacent bi-layered structure. This implies that the multi-layered structure contributes to the green coloration as well as the iridescent effect.

  7. LAMQS analysis applied to ancient Egyptian bronze coins

    NASA Astrophysics Data System (ADS)

    Torrisi, L.; Caridi, F.; Giuffrida, L.; Torrisi, A.; Mondio, G.; Serafino, T.; Caltabiano, M.; Castrizio, E. D.; Paniz, E.; Salici, A.

    2010-05-01

    Some Egyptian bronze coins, dated VI-VII sec A.D. are analyzed through different physical techniques in order to compare their composition and morphology and to identify their origin and the type of manufacture. The investigations have been performed by using micro-invasive analysis, such as Laser Ablation and Mass Quadrupole Spectrometry (LAMQS), X-ray Fluorescence (XRF), Laser Induced Breakdown Spectroscopy (LIBS), Electronic (SEM) and Optical Microscopy, Surface Profile Analysis (SPA) and density measurements. Results indicate that the coins have a similar bulk composition but significant differences have been evidenced due to different constituents of the patina, bulk alloy composition, isotopic ratios, density and surface morphology. The results are in agreement with the archaeological expectations, indicating that the coins have been produced in two different Egypt sites: Alexandria and Antinoupolis. A group of fake coins produced in Alexandria in the same historical period is also identified.

  8. Microcrystalline sodium tungsten bronze nanowire bundles as efficient visible light-responsive photocatalysts.

    PubMed

    Wang, Lei; Zhan, Jinhua; Fan, Weiliu; Cui, Guanwei; Sun, Honggang; Zhuo, Linhai; Zhao, Xian; Tang, Bo

    2010-12-14

    Microcrystalline sodium tungsten bronze nanowire bundles were obtained via a facile hydrothermal synthesis, and were applied in water purification as visible-light-driven photocatalysts for the first time. PMID:20953497

  9. 46. VIEW OF BRONZE ENGINEERS/INSPECTORS PLAQUE LOCATED ON SOUTH SIDE ...

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

    46. VIEW OF BRONZE ENGINEERS/INSPECTORS PLAQUE LOCATED ON SOUTH SIDE OF WESTERN APPROACH WALL - Tomlinson Bridge, Spanning Quinnipiac River at Forbes Street (U.S. Route 1), New Haven, New Haven County, CT

  10. Growth and ion distribution is affected by irrigation with saline water in selected landscape species grown in two consecutive growing seasons: Spring - Summer and Fall – Winter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Landscape irrigation is the second largest user of reclaimed water in industrialized countries; however its high concentration of soluble salts, especially Na+ and Cl-, may induce growth reduction and leaf necrosis or bronzing in ornamental species. The present study was conducted to determine the g...

  11. [Using Raman spectrum analysis to research corrosive productions occurring in alloy of ancient bronze wares].

    PubMed

    Jia, La-jiang; Jin, Pu-jun

    2015-01-01

    The present paper analyzes the interior rust that occurred in bronze alloy sample from 24 pieces of Early Qin bronze wares. Firstly, samples were processed by grinding, polishing and ultrasonic cleaning-to make a mirror surface. Then, a confocal micro-Raman spectrometer was employed to carry out spectroscopic study on the inclusions in samples. The conclusion indicated that corrosive phases are PbCO3 , PbO and Cu2O, which are common rusting production on bronze alloy. The light-colored circular or massive irregular areas in metallographic structure of samples are proved as Cu2O, showing that bronze wares are not only easy to be covered with red Cu2O rusting layer, but also their alloy is easy to be eroded by atomic oxygen. In other words, the rust Cu2O takes place in both the interior and exterior parts of the bronze alloy. In addition, Raman spectrum analysis shows that the dark grey materials are lead corrosive products--PbCO3 and PbO, showing the corroding process of lead element as Pb -->PbO-->PbCO3. In the texture of cast state of bronze alloy, lead is usually distributed as independent particles between the different alloy phases. The lead particles in bronze alloy would have oxidation reaction and generate PbO when buried in the soil, and then have chemical reaction with CO3(2-) dissolved in the underground water to generate PbCO3, which is a rather stable lead corrosive production. A conclusion can be drawn that the external corrosive factors (water, dissolved oxygen and carbonate, etc) can enter the bronze ware interior through the passageway between different phases and make the alloy to corrode gradually. PMID:25993834

  12. Superplasticity in an ultrahigh carbon steel-aluminum bronze laminated composite

    SciTech Connect

    Tsai, H.C.; Higashi, K.; Sherby, O.D.

    1993-12-31

    Metal laminated composites based on ultrahigh carbon steel (UHCS) and aluminum bronze can be readily prepared by solid state bonding procedures at relatively low temperatures (670 to 700{degree}C). This is attributed to the fine grain size present in each component. No apparent interdiffusion occurs between the UHCS and aluminum bronze layers either during the solid state bonding steps or during superplastic flow below the transformation temperature of UHCS (770{degree}C). Interdiffusion does occur between the UHCS and aluminum bronze layers when the laminated composite is heated above 770{degree}C as a result of the dissolution of the iron carbides to form austenite. It is shown that a high strain-rate-sensitivity exponent (m = 0.5) can be achieved in the UHCS/bronze laminated composite at elevated temperatures (750 to 850{degree}C) and at low strain rates. High elongations are observed in the laminated composite under these conditions, with a maximum elongation of 650% noted at 750{degree}C. The UHCS/bronze laminated composite shows different mechanical characteristics from a UHCS/brass laminated composite. Brass readily cracks at elevated temperature and prevents the achievement of high elongations in a UHCS/brass composite even when the strain-rate-sensitivity is high. The aluminum bronze is fine-grained and does not form cracks during elevated temperature deformation.

  13. Investigating Early/Middle Bronze Age copper and bronze axes by micro X-ray fluorescence spectrometry and neutron imaging techniques

    NASA Astrophysics Data System (ADS)

    Figueiredo, Elin; Pereira, Marco A. Stanojev; Lopes, Filipa; Marques, José G.; Santos, Joana P.; Araújo, M. Fátima; Silva, Rui J. C.; Senna-Martinez, João C.

    2016-08-01

    Micro X-ray fluorescence (micro-XRF) analysis and neutron imaging techniques, namely 2D radiography and 3D tomography, have been applied for the study of four metal axes from the Early/Middle Bronze Age in Western Iberia, a period characterized by a metallurgical change in the use of copper to bronze. Micro-XRF analysis has shown that one of the axes was produced in copper with some arsenic while the other three were produced in a copper-tin alloy (bronze) with variable tin contents and some arsenic and lead. Neutron radiography and tomography were applied to study internal heterogeneities of the axes in a non-invasive way since the specificities of neutron interaction with matter allow a suitable penetration of these relatively thick copper-based objects when compared to the use of a conventional X-ray radiography. Neutron imaging allowed the visualization of internal fissures and pores and the evaluation of their distribution, size and shape. Relevant information for the reconstruction of ancient manufacturing techniques was gathered, revealing that one ax was produced with the mold in an angle of ≈ 25°, probably to facilitate gas escape during metal pouring. Also, information regarding physical weaknesses of the axes was collected, providing relevant data for their conservation. The combination of these non-destructive techniques allowed the evaluation of the metal composition and the internal structure of the axes. Micro-XRF allowed the distinction among copper and bronze axes, and provided data about the composition of early bronzes for which data is scarce. The neutron imaging study allowed for the first time the visualization of internal heterogeneities in early bronze axes, namely pores and large voids, providing relevant information for the reconstruction of ancient manufacturing techniques and raising pertinent information regarding physical weaknesses of these types of objects.

  14. Assessing soybean leaf area and leaf biomass by spectral measurements

    NASA Technical Reports Server (NTRS)

    Holben, B. N.; Tucker, C. J.; Fan, C. J.

    1979-01-01

    Red and photographic infrared spectral radiances were correlated with soybean total leaf area index, green leaf area index, chlorotic leaf area index, green leaf biomass, chlorotic leaf biomass, and total biomass. The most significant correlations were found to exist between the IR/red radiance ratio data and green leaf area index and/or green leaf biomass (r squared equals 0.85 and 0.86, respectively). These findings demonstrate that remote sensing data can supply information basic to soybean canopy growth, development, and status by nondestructive determination of the green leaf area or green leaf biomass.

  15. Holes in teeth - Dental caries in Neolithic and Early Bronze Age populations in Central Germany.

    PubMed

    Nicklisch, Nicole; Ganslmeier, Robert; Siebert, Angelina; Friederich, Susanne; Meller, Harald; Alt, Kurt W

    2016-01-01

    This study provides diachronic insight into the epidemiology of carious defects in teeth of Neolithic and Early Bronze Age populations in Central Germany over a period of 4000 years. The data were retrieved from skeletal remains uncovered at 21 sites throughout the Middle Elbe-Saale region (MES), comprising a total of 494 individuals with preserved teeth. The data generated were examined for age- and sex-related differences in order to gain information about the dietary habits and socio-economic structures of the period with the goal of identifying potential diachronic changes. The results indicated that dietary habits changed over the course of the Neolithic period: the prevalence of caries significantly decreased between the Early and Late Neolithic. The adults from the Early Neolithic sample, particularly those from the LBK bore the highest rate of caries. This highlights the essential importance of cereals in the diet of the early farmers in the Middle Elbe-Saale region. As time went on, meat and dairy products became more and more important, which had a positive impact on dental health. The data also show sex-specific differences: women were more often affected by caries than men and female jaws also generally exhibited greater numbers of carious teeth than their male counterparts. Dental health is a reflection of both biological factors and of economic and sociocultural structures. PMID:25765291

  16. Physiological Characteristics of Fe Accumulation in the `Bronze' Mutant of Pisum sativum L., cv `Sparkle' E107 (brz brz) 1

    PubMed Central

    Welch, Ross M.; LaRue, Thomas A.

    1990-01-01

    The pea (Pisum sativum L.) mutant, E107 (brz, brz) accumulated extremely high concentrations of Fe in its older leaves when grown in light rooms in either defined nutrient media or potting mix, or outdoors in soil. Leaf symptoms (bronze color and necrosis) were correlated with very high Fe concentrations. When E107 plants were grown in nutrient solutions supplied 10 μm Fe, as the Fe(III)-N,N′-ethylenebis[2-(2-hydroxyphenyl)glycine] chelate, their roots released higher concentrations of Fe(III) reducing substances to the nutrient media than did roots of the normal parent cv, `Sparkle.' Reciprocal grafting experiments demonstrated that the high concentrations of Fe in the shoot was controlled by the genotype of the root. In short-term 59Fe uptake studies, 15-day-old E107 seedlings exhibited higher rates of Fe absorption than did `Sparkle' seedlings under Fe-adequate growth conditions. Iron deficiency induced accelerated short-term Fe absorption rates in both mutant and normal genotypes. Iron-treated E107 roots also released larger amounts of both protons and Fe(III) reductants into their nutrient media than did iron-treated `Sparkle' roots. Furthermore, the mutant translocated proportionately more Fe to its shoot than did the parent regardless of Fe status. PMID:16667529

  17. Coming of leaf age: control of growth by hydraulics and metabolics during leaf ontogeny.

    PubMed

    Pantin, Florent; Simonneau, Thierry; Muller, Bertrand

    2012-10-01

    Leaf growth is the central process facilitating energy capture and plant performance. This is also one of the most sensitive processes to a wide range of abiotic stresses. Because hydraulics and metabolics are two major determinants of expansive growth (volumetric increase) and structural growth (dry matter increase), we review the interaction nodes between water and carbon. We detail the crosstalks between water and carbon transports, including the dual role of stomata and aquaporins in regulating water and carbon fluxes, the coupling between phloem and xylem, the interactions between leaf water relations and photosynthetic capacity, the links between Lockhart's hydromechanical model and carbon metabolism, and the central regulatory role of abscisic acid. Then, we argue that during leaf ontogeny, these interactions change dramatically because of uncoupled modifications between several anatomical and physiological features of the leaf. We conclude that the control of leaf growth switches from a metabolic to a hydromechanical limitation during the course of leaf ontogeny. Finally, we illustrate how taking leaf ontogeny into account provides insights into the mechanisms underlying leaf growth responses to abiotic stresses that affect water and carbon relations, such as elevated CO2, low light, high temperature and drought. PMID:22924516

  18. Diel leaf growth of soybean: a novel method to analyze two-dimensional leaf expansion in high temporal resolution based on a marker tracking approach (Martrack Leaf)

    PubMed Central

    2013-01-01

    Background We present a novel method for quantitative analysis of dicot leaf expansion at high temporal resolution. Image sequences of growing leaves were assessed using a marker tracking algorithm. An important feature of the method is the attachment of dark beads that serve as artificial landmarks to the leaf margin. The beads are mechanically constricted to the focal plane of a camera. Leaf expansion is approximated by the increase in area of the polygon defined by the centers of mass of the beads surrounding the leaf. Fluctuating illumination conditions often pose serious problems for tracking natural structures of a leaf; this problem is circumvented here by the use of the beads. Results The new method has been used to assess leaf growth in environmental situations with different illumination conditions that are typical in agricultural and biological experiments: Constant illumination via fluorescent light tubes in a climate chamber, a mix of natural and artificial illumination in a greenhouse and natural illumination of the situation on typical summer days in the field. Typical features of diel (24h) soybean leaf growth patterns were revealed in all three conditions, thereby demonstrating the general applicability of the method. Algorithms are provided to the entire community interested in using such approaches. Conclusions The implementation Martrack Leaf presented here is a robust method to investigate diel leaf growth rhythms both under natural and artificial illumination conditions. It will be beneficial for the further elucidation of genotype x environment x management interactions affecting leaf growth processes. PMID:23883317

  19. Effect of the severe plastic deformation and aging temperature on the strengthening, structure, and wear resistance of a beryllium bronze

    NASA Astrophysics Data System (ADS)

    Korshunov, L. G.; Korznikov, A. V.; Chernenko, N. L.

    2011-04-01

    The effect of the aging temperature, severe plastic deformation by equal-channel angular (ECA) pressing at 400°C, and subsequent aging on the rate of wear, friction coefficient, and microhardness of a commercial beryllium bronze Br.B2 quenched from 800°C has been investigated. The bronze structure before and after tribological tests has been studied with the help of metallographic and electron-microscopic methods of analysis. It has been shown that tempering (aging) of the bronze at 250-400°C for 3 h leading to a sharp growth of the hardness substantially increases the wear rate of the bronze in pair with the steel 45 under the conditions of both dry and boundary sliding friction. The cause of this is a decrease in the toughness of the surface layer of the bronze due to the precipitation of particles of the strengthening γ' phase (CuBe) from the α solid solution. Severe plastic deformation (ECA pressing) markedly enhances the wear resistance of the bronze subjected to subsequent aging at 250-400°C. This is because ECA pressing favors the formation of an extremely dispersed nanocrystalline structure with α-phase crystals 40-50 nm in size at the wear surface of the bronze; whereas in the friction zone of the quenched bronze or the quenched and aged bronze, there arises a significantly less dispersed structure with matrix crystals to 300 nm in size. It has been assumed that under conditions of the rotational mechanism of plastic deformation operating upon sliding friction in the near-surface layer of the bronze, the increase in dispersity of its structure attained by using ECA pressing enhances the toughness and, correspondingly, wear resistance of the aged bronze.

  20. Tracing the dynamic life story of a Bronze Age Female

    NASA Astrophysics Data System (ADS)

    Margarita Frei, Karin; Mannering, Ulla; Kristiansen, Kristian; Allentoft, Morten E.; Wilson, Andrew S.; Skals, Irene; Tridico, Silvana; Louise Nosch, Marie; Willerslev, Eske; Clarke, Leon; Frei, Robert

    2015-05-01

    Ancient human mobility at the individual level is conventionally studied by the diverse application of suitable techniques (e.g. aDNA, radiogenic strontium isotopes, as well as oxygen and lead isotopes) to either hard and/or soft tissues. However, the limited preservation of coexisting hard and soft human tissues hampers the possibilities of investigating high-resolution diachronic mobility periods in the life of a single individual. Here, we present the results of a multidisciplinary study of an exceptionally well preserved circa 3.400-year old Danish Bronze Age female find, known as the Egtved Girl. We applied biomolecular, biochemical and geochemical analyses to reconstruct her mobility and diet. We demonstrate that she originated from a place outside present day Denmark (the island of Bornholm excluded), and that she travelled back and forth over large distances during the final months of her life, while consuming a terrestrial diet with intervals of reduced protein intake. We also provide evidence that all her garments were made of non-locally produced wool. Our study advocates the huge potential of combining biomolecular and biogeochemical provenance tracer analyses to hard and soft tissues of a single ancient individual for the reconstruction of high-resolution human mobility.

  1. Tracing the dynamic life story of a Bronze Age Female

    PubMed Central

    Margarita Frei, Karin; Mannering, Ulla; Kristiansen, Kristian; Allentoft, Morten E.; Wilson, Andrew S.; Skals, Irene; Tridico, Silvana; Louise Nosch, Marie; Willerslev, Eske; Clarke, Leon; Frei, Robert

    2015-01-01

    Ancient human mobility at the individual level is conventionally studied by the diverse application of suitable techniques (e.g. aDNA, radiogenic strontium isotopes, as well as oxygen and lead isotopes) to either hard and/or soft tissues. However, the limited preservation of coexisting hard and soft human tissues hampers the possibilities of investigating high-resolution diachronic mobility periods in the life of a single individual. Here, we present the results of a multidisciplinary study of an exceptionally well preserved circa 3.400-year old Danish Bronze Age female find, known as the Egtved Girl. We applied biomolecular, biochemical and geochemical analyses to reconstruct her mobility and diet. We demonstrate that she originated from a place outside present day Denmark (the island of Bornholm excluded), and that she travelled back and forth over large distances during the final months of her life, while consuming a terrestrial diet with intervals of reduced protein intake. We also provide evidence that all her garments were made of non-locally produced wool. Our study advocates the huge potential of combining biomolecular and biogeochemical provenance tracer analyses to hard and soft tissues of a single ancient individual for the reconstruction of high-resolution human mobility. PMID:25994525

  2. Exploring the bronzing effect at the surface of ink layers

    NASA Astrophysics Data System (ADS)

    Hébert, Mathieu; Mallet, Maxime; Deboos, Alexis; Chavel, Pierre; Kuang, Deng-Feng; Hugonin, Jean-Paul; Besbes, Mondher; Cazier, Anthony

    2015-03-01

    We investigate the optical phenomenon responsible for the colored shine that sometimes appears at the surface of ink layers in the specular direction, often called bronzing or gloss differential. It seems to come from the wavelength-dependent refractive index of the ink, which induces a wavelength-dependent reflectance of the ink-air interface. Our experiments on cyan and magenta inkjet inks confirm this theory. Complex refractive indices can be obtained from measurements of the spectral reflectance and transmittance of a transparency film coated with the ink. We propose a correction of the classical Clapper-Yule model in order to include the colored gloss in the prediction of the spectral reflectance of an inked paper. We also explored effects of scattering by the micrometric or nanometric roughness of the ink surface. The micrometric roughness, easy to model with a geometrical optics model, can predict the spreading of the colored gloss over a large cone. Electromagnetic models accounting for the effect of the nanometric roughness of the surface also predict the attenuation of short wavelengths observed under collimated illumination.

  3. Laser recleaning of a Bronze Age prehistoric dolmen

    NASA Astrophysics Data System (ADS)

    Daurelio, G.; Andriani, S. E.; Catalano, I. M.; Albanese, A.

    2007-05-01

    Dolmen La Chianca (XVI-XV century B.C.) is one of the most important megalithic buildings in Europe for its state of conservation and for the great number of findings that were discovered there (human remains, ceramic vases, pendants, bronze objects, obsidian and silica blades etc.). The building was defaced by many writings made using different markers (permanent black, correction ink pen, ballpoint pen, pencil, water-based coloured markers). The writings were removed by using a Nd-YAG laser source (λ 1064 nm with pulse duration; t 8 ns ; f 2 to 20 Hz ; energy per impulse up to 280 mJ). Degradation mapping and laser cleaning with photographs, taken before, during and after the process in situ, were carried out, then different laser parameters and techniques were used to remove different ink types. A first laser cleaning was operated on the same building in 1999 by Daurelio, but vandals defaced newly the monument, then a new restoration became necessary.

  4. LAMQS and XRF analyses of ancient Egyptian bronze coins

    NASA Astrophysics Data System (ADS)

    Torrisi, L.; Caridi, F.; Borrielli, A.; Giuffrida, L.; Torrisi, A.; Mondio, G.; Mezzasalma, A.; Serafino, T.; Caltabiano, M.; Castrizio, E. D.; Paniz, E.; Romeo, M.; Salici, A.

    2010-10-01

    A set of Egyptian bronze coins, dating back to the sixth or seventh century AD, has been studied by different experimental techniques in order to compare their composition and surface morphology, the process of coinage and, possibly, to also identify the place of production. The measurements have been performed by laser ablation with mass quadrupole spectrometry and energy dispersed X-ray fluorescence. Both analyses are non-invasive and can be safely used according to the integrity requirements of the analyzed pieces. Owing to the poor number of available samples, this work, more than to solve a numismatic question, has been carried out in order to test the validity of the above experimental techniques in view of further analyses on the same coins, based on better quality statistics. The preliminary results, presented in this paper, indicate significant differences in the chemistry of the coins' patina, i.e. composition and isotopic species content. This seems to support, in agreement with the archaeological expectations, the hypothesis of the existence of a local mint in Antinoopolis, never before considered in Egyptian numismatics.

  5. Gold and gold working in Late Bronze Age Northern Greece.

    PubMed

    Vavelidis, M; Andreou, S

    2008-04-01

    Numerous objects of gold displaying an impressive variety of types and manufacturing techniques are known from the Late Bronze Age (LBA) contexts of Mycenaean Greece, but very little is known about the origin and processing of gold during the second millennium B.C: . Ancient literature and recent research indicate that northern Greece is probably the richest gold-bearing region in Greece, and yet, very little evidence exists regarding the exploitation of its deposits and the production as well as use of gold in the area during prehistory. The unusual find of a group of small stone crucibles at the prehistoric settlement of Thessaloniki Toumba, one with visible traces of gold melting, proves local production and offers a rare opportunity to examine the process of on-site gold working. Furthermore, the comparison of the chemical composition of prehistoric artefacts from two settlements with those of gold deposits in their immediate areas supports the local extraction of gold and opens up the prospect for some of the Mycenaean gold to have originated in northern Greece. The scarcity of gold items in northern Greek LBA contexts may not represent the actual amount of gold produced and consumed, but could be a result of the local social attitudes towards the circulation and deposition of artefacts from precious metals. PMID:18087685

  6. Tracing the dynamic life story of a Bronze Age Female.

    PubMed

    Frei, Karin Margarita; Mannering, Ulla; Kristiansen, Kristian; Allentoft, Morten E; Wilson, Andrew S; Skals, Irene; Tridico, Silvana; Nosch, Marie Louise; Willerslev, Eske; Clarke, Leon; Frei, Robert

    2015-01-01

    Ancient human mobility at the individual level is conventionally studied by the diverse application of suitable techniques (e.g. aDNA, radiogenic strontium isotopes, as well as oxygen and lead isotopes) to either hard and/or soft tissues. However, the limited preservation of coexisting hard and soft human tissues hampers the possibilities of investigating high-resolution diachronic mobility periods in the life of a single individual. Here, we present the results of a multidisciplinary study of an exceptionally well preserved circa 3.400-year old Danish Bronze Age female find, known as the Egtved Girl. We applied biomolecular, biochemical and geochemical analyses to reconstruct her mobility and diet. We demonstrate that she originated from a place outside present day Denmark (the island of Bornholm excluded), and that she travelled back and forth over large distances during the final months of her life, while consuming a terrestrial diet with intervals of reduced protein intake. We also provide evidence that all her garments were made of non-locally produced wool. Our study advocates the huge potential of combining biomolecular and biogeochemical provenance tracer analyses to hard and soft tissues of a single ancient individual for the reconstruction of high-resolution human mobility. PMID:25994525

  7. Composition and corrosion phases of Etruscan Bronzes from Villanovan Age

    NASA Astrophysics Data System (ADS)

    Festa, G.; Caroppi, P. A.; Filabozzi, A.; Andreani, C.; Arancio, M. L.; Triolo, R.; Lo Celso, F.; Benfante, V.; Imberti, S.

    2008-03-01

    A neutron diffraction (ND) and neutron tomography (NT) study of laminated ancient bronzes was performed at the ISIS (Rutherford Appleton Laboratory, UK) neutron source and at the BENSC reactor (Hahn-Meitner Institut, Germany). The samples are part of an 8th century BC Etruscan collection discovered in the necropolises of Osteria-Poggio Mengarelli and Cavalupo in the Vulci area (Viterbo, Italy). The study allowed us to derive—in a totally non-destructive manner—information related to the main composition of the objects, possible presence of alterations and their nature, crusts and inclusions, as well as structure of the bulk. The presence of some components is linked to a variety of questions such as the correct determination of the historical and cultural timeframe, place and method of production, technologies adopted and conditions for restoration and preservation. Moreover, the data analysis of corrosion products provides information about the past environments and the physical/chemical events that transformed the objects into a partially corroded matrix.

  8. A case of bronze turkey twins developing from hatching.

    PubMed

    Damaziak, K; Michalczuk, M; Zdanowska-Sąsiadek, Ż; Niemiec, J

    2015-04-01

    A double-yolked egg that was laid by an 11-month-old bronze turkey hen on 2 April, 2013 was reported. The presented case of developing turkey twin embryos is the first ever described case for this species. The egg weighed 125 g and had 74.6 mm in length and 53.0 mm in width. The embryos died between the 23rd and 24th day of incubation. Both twin 1 and twin 2 were fully developed with body weights of: 37.7 g and 40.3 g, respectively. The likely causes of death include inappropriate arrangement of embryos and insufficient gas exchange in the last period of incubation. The embryos were arranged along the long axis of the egg, one underneath the other, and were closely adhering to one another. The twins were different in plumage pigmentation. In twin 1, a spontaneous mutation of plumage pigmentation (B) was observed, whereas twin 2 showed appropriate pigmentation (b+) in respect to parents. PMID:25537764

  9. Yellow leaf blotch

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Yellow leaf blotch occurs worldwide in temperate climates. The disease is reported from countries in Asia, Australasia, Oceania, Europe, North America, Central America, the West Indies, and South America. In the northern Great Plains of North America, it is often the major leaf disease on alfalfa....

  10. Fabricating Aluminum Bronze Rotating Band for Large-Caliber Projectiles by High Velocity Arc Spraying

    NASA Astrophysics Data System (ADS)

    Wu, Bin; Fang, Ling-hui; Chen, Xiao-lei; Zou, Zhi-qiang; Yu, Xu-hua; Chen, Gang

    2014-02-01

    The necessity of finding new rotating band materials and developing corresponding joining technologies for large-caliber projectiles has been revealed by the recent increase in the ballistic performance of high loads. In this paper, aluminum bronze coatings were fabricated by the high velocity arc spraying (HVAS) technique. Microstructure and microhardness of the prepared coatings were investigated. Ring-on-disk dry sliding wear tests were conducted in an ambient condition to examine the tribological behavior of the coatings. Quasi-static engraving processes of rotating bands made of as-sprayed aluminum bronze coating and bulk copper were studied using rate-controlled push test methodology on an MTS 810 Material Testing System. The results show that the as-sprayed aluminum bronze coatings have a dense microstructure with porosity of about 1.6%. Meanwhile, the as-sprayed coating presents a higher microhardness than pure copper. The friction coefficient of coatings is about 0.2-0.3 in the steady state. Tribological mechanisms of the as-sprayed coatings were discussed. The engraving test results show that the aluminum bronze rotating band presents high bonding strength and good plasticity. The HVAS aluminum bronze coating should be a possible substitute for the state-of-the-art copper rotating band.

  11. 14C dating of the Early to Late Bronze Age stratigraphic sequence of Aegina Kolonna, Greece

    NASA Astrophysics Data System (ADS)

    Wild, E. M.; Gauß, W.; Forstenpointner, G.; Lindblom, M.; Smetana, R.; Steier, P.; Thanheiser, U.; Weninger, F.

    2010-04-01

    Aegina Kolonna, located in the center of the Saronic Gulf in the Aegean Mediterranean (Greece), is one of the major archaeological sites of the Aegean Bronze Age with a continuous stratigraphic settlement sequence from the Late Neolithic to the Late Bronze Age. Due to its position next to the maritime cross roads between central mainland Greece, the northeast Peloponnese, the Cyclades and Crete, the island played an important role in the trade between these regions. In the course of new excavations, which focused on the exploration of the Early, Middle and Late Bronze Age at Kolonna, several short lived samples from different settlement phases have been 14C-dated with the AMS method at the VERA laboratory. Bayesian sequencing of the 14C data according to the stratigraphic position of the samples in the profile was performed to enable estimates of the transition time between the cultural phases. The Aegina Kolonna 14C sequence is one of the longest existing so far for the Aegean Bronze Age, and therefore of major importance for the absolute Bronze Age chronology in this region. Preliminary results indicate that the Middle Helladic period seems to have started earlier and lasted longer than traditionally assumed. Further, at the present stage of our investigation we can give also a very tentative time frame for the Santorini volcanic eruption which seems to be in agreement with the science derived VDL date.

  12. Resonance enhanced multiphoton ionization/secondary neutral mass spectrometry and cesium attachment secondary ion mass spectrometry of bronze : a comparison.

    SciTech Connect

    McCann, M. P.; Calaway, W. F.; Pellin, M. J.; Veryovkin, I. V.; Constantinides, I.; Adriaens, A.; Adams, F.; Materials Science Division; Sam Houston State Univ.; Univ. of Antwerp

    2002-05-01

    Archaeologists have considerable interests in ancient bronzes. They want to know how these alloys were produced and how they corroded with time. Modern bronzes, with compositions very close to that of some ancient bronzes, have been produced and two methods were examined to characterize one of these modern bronzes. Analysis of this modern bronze using resonance enhanced multiphoton ionization/secondary neutral mass spectrometry (REMPI/SNMS) is examined in detail and compared to cesium attachment secondary ion mass spectrometry (CsAMS) results. Both REMPI/SNMS and CsAMS were used to quantify the composition of Fe, Ni and Mn in a modern quaternary bronze designed to serve as a certified reference material for an ancient bronze. Both methods exhibit reduced matrix effects when compared to secondary ion mass spectrometry (SIMS) and thus quantification should be simplified. It was found that when relative sensitivity factors obtained from a standard bronze material are used to calibrate the instruments, the REMPI/SNMS measurements yield results that were more sensitive and more accurate.

  13. Summer (sub-arctic) versus winter (sub-tropical) production affects on spinach leaf bio-nutrients: Vitamins (C, E, Folate, K1, provitamin A), lutein, phenolics, and antioxidants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Comparison of spinach (Spinacia oleracea L.) cultivars Lazio and Samish grown during the summer solstice in the sub-arctic versus the winter solstice in the sub-tropics provided insight into interactions between plant environment (day length, light intensity, ambient temperatures), cultivar and leaf...

  14. How do leaf veins influence the worldwide leaf economic spectrum? Review and synthesis.

    PubMed

    Sack, Lawren; Scoffoni, Christine; John, Grace P; Poorter, Hendrik; Mason, Chase M; Mendez-Alonzo, Rodrigo; Donovan, Lisa A

    2013-10-01

    Leaf vein traits are implicated in the determination of gas exchange rates and plant performance. These traits are increasingly considered as causal factors affecting the 'leaf economic spectrum' (LES), which includes the light-saturated rate of photosynthesis, dark respiration, foliar nitrogen concentration, leaf dry mass per area (LMA) and leaf longevity. This article reviews the support for two contrasting hypotheses regarding a key vein trait, vein length per unit leaf area (VLA). Recently, Blonder et al. (2011, 2013) proposed that vein traits, including VLA, can be described as the 'origin' of the LES by structurally determining LMA and leaf thickness, and thereby vein traits would predict LES traits according to specific equations. Careful re-examination of leaf anatomy, published datasets, and a newly compiled global database for diverse species did not support the 'vein origin' hypothesis, and moreover showed that the apparent power of those equations to predict LES traits arose from circularity. This review provides a 'flux trait network' hypothesis for the effects of vein traits on the LES and on plant performance, based on a synthesis of the previous literature. According to this hypothesis, VLA, while virtually independent of LMA, strongly influences hydraulic conductance, and thus stomatal conductance and photosynthetic rate. We also review (i) the specific physiological roles of VLA; (ii) the role of leaf major veins in influencing LES traits; and (iii) the role of VLA in determining photosynthetic rate per leaf dry mass and plant relative growth rate. A clear understanding of leaf vein traits provides a new perspective on plant function independently of the LES and can enhance the ability to explain and predict whole plant performance under dynamic conditions, with applications towards breeding improved crop varieties. PMID:24123455

  15. The huastec region: a second locus for the production of bronze alloys in ancient mesoamerica.

    PubMed

    Hosler, D; Stresser-Pean, G

    1992-08-28

    Chemical analyses of 51 metal artifacts, one ingot, and two pieces of intermediate processed material from two Late Post Classic archeological sites in the Huastec area of Eastern Mesoamerica point to a second production locus for copper-arsenic-tin alloys, copper-arsenic-tin artifacts, and probably copper-tin and copper-arsenic bronze artifacts. Earlier evidence had indicated that these bronze alloys were produced exclusively in West Mexico. West Mexico was the region where metallurgy first developed in Mesoamerica, although major elements of that technology had been introduced from the metallurgies of Central and South America. The bronze working component of Huastec metallurgy was transmitted from the metalworking regions of West Mexico, most likely through market systems that distributed Aztec goods. PMID:17742754

  16. Corrosion of 85-5-5-5 bronze in natural and synthetic acid rain

    NASA Astrophysics Data System (ADS)

    Morselli, L.; Bernardi, E.; Chiavari, C.; Brunoro, G.

    In order to investigate the decay of bronzes exposed to acid wet depositions, a comparative study has been performed by following the corrosion behaviour of different sets of bronze specimens exposed either to natural rain or to a similar solution, without organic compounds, artificially reproduced in laboratory. The as cast G85 bronze specimens were exposed to aggressive solutions for different periods through a wet-dry technique. The pH trend of the solutions and the amount of metals transferred into the solutions were periodically monitored. OM, SEM, XRD, RAMAN analyses and ac electrochemical measurements were performed on the artificially weathered specimens. Preliminary results, showing the difference between the ageing in natural and synthetic rain, suggest the influence of the organic components on the corrosion process. In particular, the growth of a more uniform protective layer of corrosion products on the metal surface exposed to the natural rain could be attributed to these components.

  17. Boiling heat transfer on single phosphor bronze and copper mesh microstructures

    NASA Astrophysics Data System (ADS)

    Orman, Łukasz J.

    2014-03-01

    The paper presents experimental results of boiling heat transfer of distilled water and ethyl alcohol on surfaces covered with single layers of wire mesh structures made of phosphor bronze and copper. For each material two kinds of structures have been considered (higher and lower) in order to determine the impact of the height of the structure on boiling heat transfer. The wire diameter of the copper meshes was 0,25 mm and 0,32 mm, while of the bronze meshes: 0,20 mm and 0,25 mm. The structures had the same mesh aperture (distance between the wires - 0,50 mm for copper and 0,40 for bronze) but different wire diameter and, consequently, different height of the layers. The tests have been performed under ambient pressure in the pool boiling mode. The obtained results indicate a visible impact of the layer height on the boiling heat transfer performance of the analysed microstructures.

  18. Bronze and Iron Age Finds from Romuald's Cave, Istria: 2014 Excavation Season.

    PubMed

    Janković, Ivor; Ahern, James C M; Mihelić, Sanjin; Premuzić, Zrinka

    2015-12-01

    Archaeological excavations in Romuald's Cave (Lim Channel, Istria, Croatia) have yielded evidence of human activity stretching back to the Middle Palaeolithic. This paper reports on recent Bronze Age/Early Iron Age discoveries uncovered during excavations as part of the Croatian National Science Foundation funded project: "Archaeological Investigations into the Late Pleistocene and Early Holocene of the Lim Channel, Istria". Fragmentary skeletal remains from at least two individuals were excavated, and a direct radiocarbon date from one of the remains is commensurate with a Bronze Age attribution. The recovered ceramics confirm this age attribution, although they range from the Middle Bronze Age to incipient Iron Age in character. Furthermore, the ceramics indicate that the human activities in Romuald's Cave were associated with the nearby settlements of Gradina and St. Martin. PMID:26987164

  19. Spinal arthritis and physical stress at Bronze Age Harappa.

    PubMed

    Lovell, N C

    1994-02-01

    This study examines joint changes in the vertebral skeleton in human remains excavated in 1987 and 1988 at Bronze Age Harappa, an urban center of the Indus Valley civilization. The sample consists of 23 complete skeletons from primary burial context, the partial remains of more than 69 other individuals, and hundreds of skeletal elements from secondary context, totalling 3,084 vertebral joint margins and articular surfaces. Marginal bone proliferation, pitting of articular surfaces, eburnation, and ankylosis were scored macroscopically for vertebral body margins and surfaces and posterior apophyseal facet joints. Marginal lipping is far more prevalent on the vertebral bodies than on the apophyseal facets and surface pitting is also more frequent on vertebral bodies although its expression is relatively low overall. Cervical vertebrae in this sample exhibit the same amount of marginal new bone and much more surface pitting of the vertebral bodies than do either thoracic or lumbar vertebrae; the cervical segment also exhibits the most severe expressions of both types of lesions. In addition, although the frequencies of cervical and lumbar posterior facet involvement are similar, the cervical facets exhibit much more severe lipping as well as the only cases of eburnation and ankylosis. Pitting of the posterior facets is most common in the lumbar segment, but the cervical examples are the only severe cases. It is proposed that the severe joint changes in the cervical spine result from trauma, perhaps accumulated microtrauma from activity stresses. There are no age or sex associated patterns in the frequency of arthritis although this result may be influenced by the small proportions of the total sample for which age and sex could be determined. PMID:8147433

  20. Leaf growth is conformal.

    PubMed

    Alim, Karen; Armon, Shahaf; Shraiman, Boris I; Boudaoud, Arezki

    2016-01-01

    Growth pattern dynamics lie at the heart of morphogenesis. Here, we investigate the growth of plant leaves. We compute the conformal transformation that maps the contour of a leaf at a given stage onto the contour of the same leaf at a later stage. Based on the mapping we predict the local displacement field in the leaf blade and find it to agree with the experimentally measured displacement field to 92%. This approach is applicable to any two-dimensional system with locally isotropic growth, enabling the deduction of the whole growth field just from observation of the tissue contour. PMID:27597439

  1. Processing and characterization of in-situ aluminum bronze titanium carbide composites

    NASA Astrophysics Data System (ADS)

    Pillai, Balathandan S.

    The present study was carried out to develop a process for manufacturing in-situ aluminum bronze titanium carbide (TiC) friction drums using the centrifugal casting method and to characterize the material under optimum performance. The in-situ method of manufacturing is based on the reactive gas injection technique (RGI). The gas used in this study is high purity methane (CH 4). It was found that the methane gas injection time into the molten bath of aluminum bronze alloyed with titanium promotes the formation of titanium carbide (TiC) in the bronze matrix. The maximum amount of TiC incorporated in the matrix was 3.1 wt.%. This lead to 11.5 wt.% incorporation of TiC in the inner diameter of centrifugal castings as carbide particles drifted towards this region due to the centrifugal forces and their relatively low density. The hardness and strength of these composites when compared with the as cast condition was improved by heat treatment. However, the alloy ductility was decreased at the expense of the strength. It was found that the wear resistance properties of the composites were superior to those of pure cast and heat treated aluminum bronze currently in use. Optical and Scanning Electron Microscopy indicated that the composite surfaces did not scratch deeply when wearing against a hardened 4340 steel. The wear resistance of the as cast aluminum bronze was inferior to that of heat treated one. Moreover, the heat treated aluminum bronze showed a lack of high abrasion resistance. The frictional coefficient was relatively low for the as cast aluminum bronze as a result of adhesive wear behavior for the load and speed chosen in this present investigation. The corrosion studies showed that these composites do not lead to improved corrosion resistance in marine water environments. Apparently, there is a galvanic corrosion of TiC to bronze. In addition, pitting was observed on the corroded surfaces and increased with the volume fraction of TiC. Model validation was

  2. Neutron Imaging of Archaeological Bronzes at the Oak Ridge National Laboratory

    NASA Astrophysics Data System (ADS)

    Ryzewski, K.; Herringer, S.; Bilheux, H.; Walker, L.; Sheldon, B.; Voisin, S.; Bilheux, J.-C.; Finocchiaro, V.

    This article presents the initial results of 2-D and 3-D neutron imaging of bronze artifacts using the CG-1D prototype beamline at the High Flux Isotope Reactor (HFIR) located at the Oak Ridge National Laboratory (ORNL). Neutron imaging is a non-destructive technique capable of producing unprecedented three-dimensional information on archaeomaterials, including qualitative, quantitative, and visual data on impurities, composition change, voids, and structure at macro-scale levels. The initial results presented in this publication highlight how information from neutron imaging can provide otherwise inaccessible details about the methods and materials that ancient craftspeople used in creating bronze objects.

  3. Symbolic Metal Bit and Saddlebag Fastenings in a Middle Bronze Age Donkey Burial

    PubMed Central

    Bar-Oz, Guy; Nahshoni, Pirhiya; Motro, Hadas; Oren, Eliezer D.

    2013-01-01

    Here we report the unprecedented discovery of the skeleton of a ritually interred donkey with a metal horse bit in association with its teeth and saddlebag fastenings on its back. This discovery in the Middle Bronze Age III sacred precinct (1700/1650-1550 BCE) at Tel Haror, Israel, presents a unique combination of evidence for the early employment of equid harnessing equipment, both for chariot bridling (horse bit) and pack animals (saddlebags). The ritually deposited donkey with its unique accoutrements advances our understanding of the broad social and religious significance of equids in the Levantine Bronze Age, previously known mainly from textual and iconographical sources. PMID:23484046

  4. Surface characterization of a corroded bronze-leaded alloy in a salt spray cabinet

    NASA Astrophysics Data System (ADS)

    de Figueiredo Junior, João Cura D.'Ars; de Freitas Cunha Lins, Vanessa; De Bellis, Vito Modesto

    2007-06-01

    The corrosion products of a TM 23 bronze-leaded alloy (Cu 72%, Pb 15%, Zn 8% and Sn 5%) were obtained in a salt spray cabinet after exposition during 120 h and 1000 h. The products obtained were studied using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. The major products of bronze-leaded corrosion were oxides and basic salts of Cu, CuCl 2·3Cu(OH) 2, and Pb, Pb(OH)Cl. The results can be attributed to a kinetic control of the corrosion reactions.

  5. Leaf Tissue Senescence

    PubMed Central

    Manos, Peter J.; Goldthwaite, Jonathan

    1975-01-01

    During winter, excised leaf tissue from Rumex obtusifolius degrades chlorophyll at twice the summer rate but the plant hormones, gibberellic acid and zeatin, inhibit the senescence rate by a constant percentage, regardless of season. PMID:16659225

  6. Effects of Shading on Cerospora Leaf Spot in Bigleaf Hydrangea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shading densities significantly affected disease severities of Cercospora leaf spot on bigleaf hydrangeas. In general, lower disease severities were associated with higher shading densities. However, significantly differences in disease severities among cultivars could not be detected in higher sha...

  7. Effects of Shading on Cercospora Leaf Spot in Bigleaf Hydrangea

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shading densities significantly affected severity of Cercospora leaf spot on bigleaf hydrangeas. In general, lower disease severities were associated with higher shading densities. However, significantly differences in disease severities among cultivars could not be detected in higher shading densi...

  8. Deer predation on leaf miners via leaf abscission

    NASA Astrophysics Data System (ADS)

    Yamazaki, Kazuo; Sugiura, Shinji

    2008-03-01

    The evergreen oak Quercus gilva Blume sheds leaves containing mines of the leaf miner Stigmella sp. (Lepidoptera: Nepticulidae) earlier than leaves with no mines in early spring in Nara, central Japan. The eclosion rates of the leaf miner in abscised and retained leaves were compared in the laboratory to clarify the effects of leaf abscission on leaf miner survival in the absence of deer. The leaf miner eclosed successfully from both fallen leaves and leaves retained on trees. However, sika deer ( Cervus nippon centralis Kishida) feed on the fallen mined leaves. Field observations showed that deer consume many fallen leaves under Q. gilva trees, suggesting considerable mortality of leaf miners due to deer predation via leaf abscission. This is a previously unreported relationship between a leaf miner and a mammalian herbivore via leaf abscission.

  9. Celestial Symbolism in Central European Later Prehistory - Case Studies from the Bronze Age Carpathian Basin

    NASA Astrophysics Data System (ADS)

    Pásztor, Emília

    It is commonly held that the sun played a particularly important cultural role in later prehistoric Europe. The rise of a general European sun cult has even been suggested for the Bronze Age. During this period, the increasing use of special symbols assumed to represent the sun is easily discernible on different types of archaeological finds.

  10. Cold Spraying of Cu-Al-Bronze for Cavitation Protection in Marine Environments

    NASA Astrophysics Data System (ADS)

    Krebs, S.; Gärtner, F.; Klassen, T.

    2015-01-01

    Traveling at high speeds, ships have to face the problem of rudder cavitation-erosion. At present, the problem is countered by fluid dynamically optimized rudders, synthetic, and weld-cladded coatings on steel basis. Nevertheless, docking and repair is required after certain intervals. Bulk Cu-Al-bronzes are in use at ships propellers to withstand corrosion and cavitation. Deposited as coatings with bulk-like properties, such bronzes could also enhance rudder life times. The present study investigates the coating formation by cold spraying CuAl10Fe5Ni5 bronze powders. By calculations of the impact conditions, the range of optimum spray parameters was preselected in terms of the coating quality parameter η on steel substrates with different temperatures. As-atomized and annealed powders were compared to optimize cavitation resistance of the coatings. Results provide insights about the interplay between the mechanical properties of powder and substrate for coating formation. Single particle impact morphologies visualize the deformation behavior. Coating performance was assessed by analyzing microstructures, bond strength, and cavitation resistance. These first results demonstrate that cold-sprayed bronze coatings have a high potential for ensuring a good performances in rudder protection. With further optimization, such coatings could evolve towards a competitive alternative to existing anti-cavitation procedures.

  11. 75 FR 15764 - Culturally Significant Objects Imported for Exhibition Determinations: “Gods of Angkor: Bronzes...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-30

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF STATE Culturally Significant Objects Imported for Exhibition Determinations: ``Gods of Angkor: Bronzes From the... 15, 2003 , I hereby determine that the objects to be included in the exhibition ``Gods of...

  12. Randomised controlled trials of staged teaching for basic life support. 1. Skill acquisition at bronze stage.

    PubMed

    Assar, D; Chamberlain, D; Colquhoun, M; Donnelly, P; Handley, A J; Leaves, S; Kern, K B

    2000-06-01

    We have investigated a method of teaching community CPR in three stages instead of in a single session. These have been designated bronze, silver, and gold stages. The first involves only opening of the airway and chest compression with back blows for choking, the second adds ventilation in a ratio of compressions to breaths of 50:5, and the third is a conversion to conventional CPR. In a controlled randomised trial of 495 trainees we compared the performance in tests immediately after instruction of those who had received a conventional course and those who had had the simpler bronze level tuition. The tests were based on video recordings of simulated resuscitation scenarios and the readouts from recording manikins. Differences occurred as a direct consequence of ventilation being required in one group and not the other, some variation probably followed from unforeseen minor changes in the way that instruction was given, whilst others may have followed from the greater simplicity in the new method of training. A careful approach was followed by slightly more trainees in the conventional group whilst appreciably more in the bronze group remembered to shout for help (44% vs. 71%). A clear advantage was also seen for bronze level training in terms of those who opened the airway as taught (35% vs. 56%), for checking breathing (66% vs. 88%), and for mentioning the need to phone for an ambulance (21% vs. 32%). Little difference was observed in correct or acceptable hand position between the conventional group who were given detailed guidance and the bronze group who were instructed only to push on the centre of the chest. The biggest differences related to the number of compressions given. The mean delay to first compression was 63 s and 34 s, and the mean duration of pauses between compressions was 16 s and 9 s, respectively. Average performed rates were similar in the two groups, but more in the conventional group compressed too slowly whereas more in the bronze group

  13. A Rapid Ultrasonic Method for Nondestructive Thickness Mapping of Bronze Liner in Steel-Backed Bearing Sleeves

    SciTech Connect

    Fei Dong; Rebinsky, Douglas A.

    2004-02-26

    In this paper a nondestructive, automatic, ultrasonic scanning method was developed to permit rapid thickness mapping of the bronze liner in a steel-backed bearing sleeve. Because the sound velocity in bronze was unknown, an indirect two-step approach was used: the first step utilized a simultaneous velocity and thickness mapping method to measure the total wall thickness while the second step measured the thickness of the steel backing. The difference of the two obtained thickness maps yielded the thickness map of the bronze liner. Comparison to destructive examination results showed a measurement accuracy of approximately 20 {mu}m or 2%.

  14. A Rapid Ultrasonic Method for Nondestructive Thickness Mapping of Bronze Liner in Steel-Backed Bearing Sleeves

    NASA Astrophysics Data System (ADS)

    Fei, Dong; Rebinsky, Douglas A.

    2004-02-01

    In this paper a nondestructive, automatic, ultrasonic scanning method was developed to permit rapid thickness mapping of the bronze liner in a steel-backed bearing sleeve. Because the sound velocity in bronze was unknown, an indirect two-step approach was used: the first step utilized a simultaneous velocity and thickness mapping method to measure the total wall thickness while the second step measured the thickness of the steel backing. The difference of the two obtained thickness maps yielded the thickness map of the bronze liner. Comparison to destructive examination results showed a measurement accuracy of approximately 20 μm or 2%.

  15. Quantitative trait locus analysis of leaf dissection in tomato using Lycopersicon pennellii segmental introgression lines.

    PubMed Central

    Holtan, Hans E E; Hake, Sarah

    2003-01-01

    Leaves are one of the most conspicuous and important organs of all seed plants. A fundamental source of morphological diversity in leaves is the degree to which the leaf is dissected by lobes and leaflets. We used publicly available segmental introgression lines to describe the quantitative trait loci (QTL) controlling the difference in leaf dissection seen between two tomato species, Lycopersicon esculentum and L. pennellii. We define eight morphological characteristics that comprise the mature tomato leaf and describe loci that affect each of these characters. We found 30 QTL that contribute one or more of these characters. Of these 30 QTL, 22 primarily affect leaf dissection and 8 primarily affect leaf size. On the basis of which characters are affected, four classes of loci emerge that affect leaf dissection. The majority of the QTL produce phenotypes intermediate to the two parent lines, while 5 QTL result in transgression with drastically increased dissection relative to both parent lines. PMID:14668401

  16. Mobility in Central European Late Eneolithic and Early Bronze Age: femoral cross-sectional geometry.

    PubMed

    Sládek, Vladimír; Berner, Margit; Sailer, Robert

    2006-07-01

    Some scholars explain the absence of settlements in the Bohemian and Moravian Late Eneolithic (Corded Ware archaeological culture) as a consequence of pastoral subsistence with a high degree of mobility. However, recent archaeological studies argued that the archaeological record of the Late Eneolithic in Central Europe exhibits evidence for sedentary subsistence with mixed agriculture, similar to the subsequent Early Bronze Age. Because the archaeological data do not allow us to address unambiguously the mobility pattern in these periods, we used cross-sectional analysis of the femoral midshaft to test mobility directly on the human skeletal record. The results of femoral midshaft geometry do not support a high degree of mobility in the Late Eneolithic in Central Europe. This conclusion is supported mainly by no significant differences in male groups between the Late Eneolithic and Early Bronze Age in mechanical robusticity and shape of the femoral midshaft, although Corded Ware males still exhibit the highest absolute mean values of the diaphyseal shape (I(A-P)/I(M-L)) ratio and antero-posterior second moment of area. However, Late Eneolithic females have significantly higher torsional and overall bending rigidity because of a significantly higher medio-lateral second moment of area. This finding cannot be directly linked with a higher degree of long-distance mobility for these females. A significant difference was also found in overall decrease of size parameters of the femoral midshaft cross section for one of the Early Bronze Age samples, the Wieselburger females. Since the decrease of size and mechanical robusticity for Wieselburger females does not correspond with the parameters of Early Bronze Age females, we can expect a mosaic pattern of changes during the Late Eneolithic and Early Bronze Age period, instead of a simple unidirectional (diachronic) change of the mechanical environment. PMID:16402366

  17. Chemical bath deposition and characterization of electrochromic thin films of sodium vanadium bronzes

    SciTech Connect

    Najdoski, Metodija; Koleva, Violeta; Demiri, Sani

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer We report a new chemical bath method for the deposition of vanadium bronze thin films. Black-Right-Pointing-Pointer The films are phase mixture of NaV{sub 6}O{sub 15} and Na{sub 1.1}V{sub 3}O{sub 7.9} with 10.58% lattice water. Black-Right-Pointing-Pointer The as-deposited vanadium bronze films exhibit two-step electrochromism. Black-Right-Pointing-Pointer They change their yellow-orange color to green and then from green to blue color. Black-Right-Pointing-Pointer The method allows the preparation of films on substrates with low melting point. -- Abstract: Thin yellow-orange films of sodium vanadium oxide bronzes have been prepared from a sodium-vanadium solution (1:1) at 75 Degree-Sign C and pH = 3. The composition, structure and morphology of the films have been studied by XRD, IR spectroscopy, TG and SEM-EDX analyses. It has been established that the prepared films are a phase mixture of hydrated NaV{sub 6}O{sub 15} (predominant component) and Na{sub 1.1}V{sub 3}O{sub 7.9} with total water content of 10.58%. The sodium vanadium bronze thin films exhibit two-step electrochromism followed by color change from yellow-orange to green, and then from green to blue. The cyclic voltammetry measurements on the as-deposited and annealed vanadium bronze films reveal the existence of different oxidation/reduction vanadium sites which make these films suitable for electrochromic devices. The annealing of the films at 400 Degree-Sign C changes the composition, optical and electrochemical properties.

  18. Damped leaf flexure hinge

    NASA Astrophysics Data System (ADS)

    Chen, Zhong; Chen, Guisheng; Zhang, Xianmin

    2015-05-01

    Flexure-based mechanism like compliant actuation system embeds complex dynamics that will reduce the control bandwidth and limits their dynamic positioning precision. This paper presents a theoretical model of a leaf flexure hinge with damping layers using strain energy method and Kelvin damping model. The modified loss factor of the damped leaf flexure hinge is derived, and the equivalent viscous damping coefficient of the damped leaf hinge is obtained, which could be used to improve the pseudo-rigid-model. The free vibration signals of the hinge in three different damping configurations are measured. The experimental modal analysis also is performed on the three kinds of damped leaf flexure hinges in order to evaluate their 1st order bending natural frequency and vibration-suppressing effects. The evaluation of modified loss factor model also is performed. The experimental results indicate that the constrained layer damping can enhance the structure damping of the hinge even if only single damping layer each side, the modified loss factor model can get good predicts of a damped leaf flexure hinge in the frequency range below 1st order natural frequency, and it is necessary that the dimensional parameters of the damping layers and basic layer of the hinge should be optimized for simplification at the mechanism's design stage.

  19. Damped leaf flexure hinge.

    PubMed

    Chen, Zhong; Chen, Guisheng; Zhang, Xianmin

    2015-05-01

    Flexure-based mechanism like compliant actuation system embeds complex dynamics that will reduce the control bandwidth and limits their dynamic positioning precision. This paper presents a theoretical model of a leaf flexure hinge with damping layers using strain energy method and Kelvin damping model. The modified loss factor of the damped leaf flexure hinge is derived, and the equivalent viscous damping coefficient of the damped leaf hinge is obtained, which could be used to improve the pseudo-rigid-model. The free vibration signals of the hinge in three different damping configurations are measured. The experimental modal analysis also is performed on the three kinds of damped leaf flexure hinges in order to evaluate their 1st order bending natural frequency and vibration-suppressing effects. The evaluation of modified loss factor model also is performed. The experimental results indicate that the constrained layer damping can enhance the structure damping of the hinge even if only single damping layer each side, the modified loss factor model can get good predicts of a damped leaf flexure hinge in the frequency range below 1st order natural frequency, and it is necessary that the dimensional parameters of the damping layers and basic layer of the hinge should be optimized for simplification at the mechanism's design stage. PMID:26026549

  20. Stable isotopes of a subfossil Tamarix tree from the Dead Sea region, Israel, and their implications for the Intermediate Bronze Age environmental crisis

    NASA Astrophysics Data System (ADS)

    Frumkin, Amos

    2009-05-01

    Trees growing on the Mt. Sedom salt diapir, at the southern Dead Sea shore, were swept by runoff into salt caves and subsequently deposited therein, sheltered from surface weathering. A subfossil Tamarix tree trunk, found in a remote section of Sedom Cave is radiocarbon dated to between ˜ 2265 and 1930 BCE. It was sampled in 109 points across the tree rings for carbon and nitrogen isotopes. The Sedom Tamarix demonstrates a few hundred years of 13C and 15N isotopic enrichment, culminating in extremely high δ 13C and δ 15N values. Calibration using modern Tamarix stable isotopes in various climatic settings in Israel shows direct relationship between isotopic enrichment and climate deterioration, particularly rainfall decrease. The subfossil Tamarix probably reflects an environmental crisis during the Intermediate Bronze Age, which subsequently killed the tree ˜ 1930 BCE. This period coincides with the largest historic fall of the Dead Sea level, as well as the demise of the large regional urban center of the 3rd millennium BCE. The environmental crisis may thus explain the archaeological evidence of a shift from urban to pastoral culture during the Intermediate Bronze Age. This was apparently the most severe long-term historical drought that affected the region in the mid-late Holocene.

  1. Effects of combination of leaf resources on competition in container mosquito larvae.

    PubMed

    Reiskind, M H; Zarrabi, A A; Lounibos, L P

    2012-08-01

    Resource diversity is critical to fitness in many insect species, and may determine the coexistence of competitive species and the function of ecosystems. Plant material provides the nutritional base for numerous aquatic systems, yet the consequences of diversity of plant material have not been studied in aquatic container systems important for the production of mosquitoes. To address how diversity in leaf detritus affects container-inhabiting mosquitoes, we examined how leaf species affect competition between two container inhabiting mosquito larvae, Aedes aegypti and Aedes albopictus, that co-occur in many parts of the world. We tested the hypotheses that leaf species changes the outcome of intra- and interspecific competition between these mosquito species, and that combinations of leaf species affect competition in a manner not predictable based upon the response to each leaf species alone (i.e. the response to leaf combinations is non-additive). We find support for our first hypothesis that leaf species can affect competition, evidence that, in general, leaf combination alters competitive interactions, and no support that leaf combination impacts interspecific competition differently than intraspecific competition. We conclude that combinations of leaves increase mosquito production non-additively such that combinations of leaves act synergistically, in general, and result in higher total yield of adult mosquitoes in most cases, although certain leaf combinations for A. albopictus are antagonistic. We also conclude that leaf diversity does not have a different effect on interspecific competition between A. aegypti and A. albopictus, relative to intraspecific competition for each mosquito. PMID:22314102

  2. Synchrotron radiation-based x-ray analysis of bronze artifacts from an Iron Age site in the Judean hills.

    SciTech Connect

    Friedman, E. S.; Brody, A. J.; Young, M. L.; Almer, J. D.; Serge, C. U.; Mini, S. M.; IIT; Pacific School of Religion; Northwestern Univ.; Northern Illinois Univ.

    2008-07-01

    Seven bronze bangles from Tell en-Nasbeh, northern Judah, were investigated to understand the phase composition and manufacturing process of the artifacts, and possibly suggest a provenance for their origin. Synchrotron x-ray radiation diffraction (XRD) and fluorescence (XRF) were used in the analysis to avoid any destructive sampling and at the same time penetrate through the surface into the core metal. These techniques enabled us to determine that the bangles were not just tin bronze, but leaded tin bronze. Based on excavation reports, it is unlikely that the metal objects were manufactured locally at Tell en-Nasbeh; rather, preliminary XRD and XRF data point towards the neighboring region of Edom as their origin. Despite their political enmity during the Iron Age II, the data suggest that Judahite social demands for bronze may have fostered a strong economic relationship between these two polities.

  3. Plasticity of vulnerability to leaf hydraulic dysfunction during acclimation to drought in grapevines: an osmotic-mediated process.

    PubMed

    Martorell, Sebastian; Medrano, Hipolito; Tomàs, Magdalena; Escalona, José M; Flexas, Jaume; Diaz-Espejo, Antonio

    2015-03-01

    Previous studies have reported correlation of leaf hydraulic vulnerability with pressure-volume parameters related to cell turgor. This link has been explained on the basis of the effects of turgor on connectivity among cells and tissue structural integrity, which affect leaf water transport. In this study, we tested the hypothesis that osmotic adjustment to water stress would shift the leaf vulnerability curve toward more negative water potential (Ψ leaf ) by increasing turgor at low Ψ leaf . We measured leaf hydraulic conductance (K leaf ), K leaf vulnerability [50 and 80% loss of K leaf (P50 and P80 ); |Ψ leaf | at 50 and 80% loss of K leaf , respectively), bulk leaf water relations, leaf gas exchange and sap flow in two Vitis vinifera cultivars (Tempranillo and Grenache), under two water treatments. We found that P50 , P80 and maximum K leaf decreased seasonally by more than 20% in both cultivars and watering treatments. However, K leaf at 2 MPa increased threefold, while osmotic potential at full turgor and turgor loss point decreased. Our results indicate that leaf resistance to hydraulic dysfunction is seasonally plastic, and this plasticity may be mediated by osmotic adjustment. PMID:25132228

  4. Raspberry leaf curl virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Raspberry leaf curl virus (RLCV) is limited to hosts in the genus Rubus and is transmitted persistently by the small raspberry aphid, Aphis rubicola Oestlund. It is found only in North America, principally in the northeastern United States and southeastern Canada and in the Rocky Mountain regions of...

  5. Maple Leaf Outdoor Centre.

    ERIC Educational Resources Information Center

    Maguire, Molly; Gunton, Ric

    2000-01-01

    Maple Leaf Outdoor Centre (Ontario) has added year-round outdoor education facilities and programs to help support its summer camp for disadvantaged children. Schools, youth centers, religious groups, and athletic teams conduct their own programs, collaborate with staff, or use staff-developed programs emphasizing adventure education and personal…

  6. Bacterial leaf spot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bacterial leaf spot has been reported in Australia (Queensland), Egypt, El Salvador, India, Japan, Nicaragua, Sudan, and the United States (Florida, Iowa, Kansas, Maryland, and Wisconsin). It occasionally causes locally severe defoliation and post-emergence damping-off and stunting. The disease is...

  7. Preparation of La{sub x}V{sub 2}O{sub 5} bronze by magnetron sputtering

    SciTech Connect

    Chesnis, A.; Oginskis, A.K.; Vesene, T.

    1995-01-01

    Lanthanide vanadium bronzes Ln{sub x}V{sub 2}O{sub 5} are of interest as new materials for producing ionometric electrodes sensitive to the corresponding constituent rare-earth ions present in solution. Synthesis of these materials is, however, fairly complex and laborious. First attempts at preparing these bronzes (namely, La{sub x}V{sub 2}O{sub 5}) involved treatment conventionally used in the synthesis of vanadium bronzes: high-temperature annealing (1020 K, 24 h) of a mixture of La{sub 2}O{sub 3}, VO and V{sub 2}O{sub 5} powders in evacuated quartz tubes. Later, however, this preparation procedure was reported to yield a three-phase product containing a rare-earth orthovanadate and two vanadium oxides. Only upon annealing at high pressure (7.7-9.0 GPa), was this mixture converted to a hexagonal bronze. Here, the authors report an attempt at preparing lanthanum vanadium bronze by magnetron sputtering in an inert atmosphere from starting reagents commonly used in the synthesis of this bronze.

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

    PubMed

    Yang, Hu; Li, Jinwen; Yang, Jingping; Wang, Hua; Zou, Junliang; He, Junjun

    2014-01-01

    A Soil-Plant Analysis Development (SPAD) chlorophyll meter can be used as a simple tool for evaluating N concentration of the leaf and investigating the combined effects of nitrogen rate and leaf age on N distribution. We conducted experiments in a paddy field over two consecutive years (2008-2009) using rice plants treated with six different N application levels. N distribution pattern was determined by SPAD readings based on the temporal dynamics of N concentrations in individual leaves. At 62 days after transplantation (DAT) in 2008 and DAT 60 in 2009, leaf SPAD readings increased from the upper to lower in the rice canopy that received N levels of 150 to 375 kg ha(-1)The differences in SPAD readings between the upper and lower leaf were larger under higher N application rates. However, as plants grew, this atypical distribution of SPAD readings in canopy leaf quickly reversed to the general order. In addition, temporal dynamics of the leaf SPAD readings (N concentrations) were fitted to a piecewise function. In our model, changes in leaf SPAD readings were divided into three stages: growth, functioning, and senescence periods. The leaf growth period lasted approximately 6 days, and cumulative growing days were not affected by N application rates. The leaf functioning period was represented with a relatively stable SPAD reading related to N application rate, and cumulative growing days were extended with increasing N application rates. A quadratic equation was utilized to describe the relationship between SPAD readings and leaf age during the leaf senescence period. The rate of decrease in SPAD readings increased with the age of leaves, but the rate was slowed by N application. As leaves in the lower canopy were physiologically older than leaves in the upper canopy, the rate of decrease in SPAD readings was faster in the lower leaves. PMID:24520386

  9. Effects of Nitrogen Application Rate and Leaf Age on the Distribution Pattern of Leaf SPAD Readings in the Rice Canopy

    PubMed Central

    Yang, Jingping; Wang, Hua; Zou, Junliang; He, Junjun

    2014-01-01

    A Soil-Plant Analysis Development (SPAD) chlorophyll meter can be used as a simple tool for evaluating N concentration of the leaf and investigating the combined effects of nitrogen rate and leaf age on N distribution. We conducted experiments in a paddy field over two consecutive years (2008–2009) using rice plants treated with six different N application levels. N distribution pattern was determined by SPAD readings based on the temporal dynamics of N concentrations in individual leaves. At 62 days after transplantation (DAT) in 2008 and DAT 60 in 2009, leaf SPAD readings increased from the upper to lower in the rice canopy that received N levels of 150 to 375 kg ha−1The differences in SPAD readings between the upper and lower leaf were larger under higher N application rates. However, as plants grew, this atypical distribution of SPAD readings in canopy leaf quickly reversed to the general order. In addition, temporal dynamics of the leaf SPAD readings (N concentrations) were fitted to a piecewise function. In our model, changes in leaf SPAD readings were divided into three stages: growth, functioning, and senescence periods. The leaf growth period lasted approximately 6 days, and cumulative growing days were not affected by N application rates. The leaf functioning period was represented with a relatively stable SPAD reading related to N application rate, and cumulative growing days were extended with increasing N application rates. A quadratic equation was utilized to describe the relationship between SPAD readings and leaf age during the leaf senescence period. The rate of decrease in SPAD readings increased with the age of leaves, but the rate was slowed by N application. As leaves in the lower canopy were physiologically older than leaves in the upper canopy, the rate of decrease in SPAD readings was faster in the lower leaves. PMID:24520386

  10. Senescent leaf exudate increases mosquito survival and microbial activity

    PubMed Central

    PELZ-STELINSKI, K. S.; WALKER, E. D.; KAUFMAN, M. G.

    2010-01-01

    We conducted experiments to evaluate the effects of soluble components in senescent leaf material on the growth and development of the eastern tree hole mosquito, Aedes triseriatus (Say). Oak leaves that were either leached for three days to remove the labile nutrient fraction, or were not leached, served as basal nutrient inputs in each experiment. Mosquito performance in microcosms containing leachate only was significantly worse compared with microcosms containing leaf material in combination with either leachate or water, indicating the importance of leaf substrates to mosquito production. Adult mosquito biomass, emergence, and development time were significantly higher in microcosms containing unleached leaves compared with leached leaf material. Additions of leachate to leached leaf treatments enhanced adult production, but not to the level observed in unleached leaf treatments. Filtered and unfiltered leachate added substantial nitrogen and phosphorus to microcosms and significantly affected mosquito growth responses. Bacterial productivity and abundance were also significantly affected by leachate additions and filtering. Taken together, these results suggest that while leaves decline with respect to nutritional value during decomposition, they remain important components of the habitat as substrates for microbial growth and mosquito feeding, particularly when nutrients (here, leachate) enter the system. Our results also illustrate the importance of soluble leaf material, which enhances mosquito production through effects on microbial community dynamics. PMID:21113430

  11. Chronology for the Aegean Late Bronze Age 1700-1400 B.C.

    PubMed

    Manning, Sturt W; Ramsey, Christopher Bronk; Kutschera, Walter; Higham, Thomas; Kromer, Bernd; Steier, Peter; Wild, Eva M

    2006-04-28

    Radiocarbon (carbon-14) data from the Aegean Bronze Age 1700-1400 B.C. show that the Santorini (Thera) eruption must have occurred in the late 17th century B.C. By using carbon-14 dates from the surrounding region, cultural phases, and Bayesian statistical analysis, we established a chronology for the initial Aegean Late Bronze Age cultural phases (Late Minoan IA, IB, and II). This chronology contrasts with conventional archaeological dates and cultural synthesis: stretching out the Late Minoan IA, IB, and II phases by approximately 100 years and requiring reassessment of standard interpretations of associations between the Egyptian and Near Eastern historical dates and phases and those in the Aegean and Cyprus in the mid-second millennium B.C. PMID:16645092

  12. Laser beam treatment effect on AMPCO M4 bronze cavitation erosion resistance

    NASA Astrophysics Data System (ADS)

    Bordeasu, I.; Popoviciu, M. O.; Micu, L. M.; Oanca, O. V.; Bordeasu, D.; Pugna, A.; Bordeasu, C.

    2015-06-01

    Ship propellers must resist simultaneously to ocean water corrosion and cavitation erosion. Until now, the best material used is the bronze with great copper content. These materials are expensive and there is the tendency to reduce the copper content while maintaining good properties. Such a material is AMPCO M4 used for manufacturing details for aircraft retractable landing assemblies. As a consequence we undertake cavitation erosion tests upon this bronze. In natural state (cast or even extruded) the cavitation resistance is not acceptable so, we improved the specimens by treating them with laser beams at three different impulse powers (160, 180 and 220 W). The cavitation erosion resistance was tested in the Cavitation Laboratory of Timisoara “Politehnica” University using a vibratory device respecting the conditions imposed by ASTM G32-2010 Standard. The comparisons with the genuine material (without any treatments) show that the applied procedure increased the hardness of the melted layer as well as the cavitation erosion behavior.

  13. Atomic Structure and Charge Density Waves of Blue Bronze by Variable Temperature Scanning Tunneling Microscopy

    SciTech Connect

    Nikiforov,M.; Isakovic, A.; Bonnell, D.

    2007-01-01

    Blue bronze (K{sub 0.3}MoO{sub 3}) has been the focus of a number of scattering, transport, scanning tunneling microscopy (STM), and theoretical studies that have provided insight into the relation between atomic structure and charge-density wave (CDW) formation. However, the full extent of a relation of the CDWs to the atomic lattice and the microscopic origin of CDW pinning are still not completely resolved. In this study STM is used to distinguish the atomic structure and CDWs at the (20{bar 1}) surface. Within the STM's spatial resolution, the CDWs are incommensurate with the lattice at midrange temperatures and approach commensurability at low temperatures. Incommensurate CDWs are present on the surface and the degree of the incommensurability between blue bronze lattice and CDW lattice agree well with those determined from bulk scattering techniques.

  14. The influence of modification by superdispersed powders on the lead-tin-base bronze structure

    NASA Astrophysics Data System (ADS)

    Semenkov, I. V.; Martyushev, N. V.; Popelyukh, A. I.; Alpeisov, A. T.; Drozdov, Yu Yu; Zykova, A. P.

    2016-04-01

    The paper presents data on the influence of additives of the pre-treated aluminium oxide powder on the structure of cast lead-tin-based bronzes. Different quantities of the modifier, based on the superdispersed aluminum oxide powder, were added to the bronze melt. The studies have shown that addition of a small amount of aluminum oxide powder (0.07... 0.25 %) allows modifying the micro structure of the obtained castings. This modification includes grain refinement, reduction of the matrix dendrites size of tin solid solution in copper, as well as formation of spherical inclusions of the low-melting phase - lead. In this case, the addition of such modifier influences weakly the morphology and the quantity of solid eutectoid inclusions based on electron compound Cu31 Sn8.

  15. Studies on bronze pre-monetary signs found in Dobroudja using XRF and micro-PIXE

    NASA Astrophysics Data System (ADS)

    Constantinescu, B.; Cristea-Stan, D.; Talmatchi, G.; Ceccato, D.

    2016-03-01

    We performed compositional analyses on 180 Scythian-type arrowheads and pre-monetary signs using XRF method and on 60 small fragments of such items (approx. 100 microns diameter), sampling being performed on previously corrosion-cleaned areas on their surface, using micro-PIXE. The items are found in Dobroudja, Istros-Histria region. The most relevant for numismatists result is that for each finding place the same type of alloy was used both for fighting arrowheads and for pre-monetary signs. Our analyses revealed three types of alloys: Cu-Sn-Pb ("normal" bronze), Cu-Sn-Mn-Pb and Cu-Sn-Sb-Pb. The presence of antimony suggests the use of fahlore-type poly-metals deposits, most probably from Caucasus Mountains. The problem of ancient bronze containing manganese is more complicated; an explanation could be the use of manganese oxides as flux necessary to smelt oxidized ores.

  16. Biological affinities and adaptations of Bronze Age Bactrians: III. An initial craniometric assessment.

    PubMed

    Hemphill, B E

    1998-07-01

    Discovery of a previously unknown Bronze Age civilization (Oxus Civilization) centered on the oases of Central Asia immediately raised questions concerning the origin and interregional impacts of this civilization. Fifteen craniometric variables from 12 Bronze Age samples--encompassing 544 adults from Central Asia, Iran, the Indus Valley, and Anatolia--are compared to test which, if any, of the current hypotheses offered by archaeologists are best supported by the pattern of phenetic affinities possessed by the Oxus Civilization inhabitants of the north Bactrian oasis. Craniometric differences between samples are compared with Mahalanobis generalized distance, and patterns of phenetic affinity are assessed with two types of cluster analysis (WPGMA, neighbor-joining method), multidimensional scaling, and principal coordinates analysis. Results obtained by this analysis indicate that current hypotheses for both the origin and interregional impacts of Oxus Civilization populations are incomplete. PMID:9696149

  17. Comparative modeling of Bronze Age land use in the Malatya Plain (Turkey)

    NASA Astrophysics Data System (ADS)

    Arıkan, Bülent; Restelli, Francesca Balossi; Masi, Alessia

    2016-03-01

    Computational modeling in archeology has proven to be a useful tool in quantifying changes in the paleoenvironment. This especially useful method combines data from diverse disciplines to answer questions focusing on the complex and non-linear aspects of human-environment interactions. The research presented here uses various proxy records to compare the changes in climate during the Bronze Age in the Malatya Plain in eastern Anatolia, which is situated at the northern extremity of northern Mesopotamia. Extensive agropastoral land use modeling was applied to three sites of different size and function in the Malatya Plain during the Early Bronze Age I period to simulate the varying scale and intensity of human impacts in relation to changes in the level of social organization, demography, and temporal length. The results suggest that even in land use types subjected to a light footprint, the scale and intensity of anthropogenic impacts change significantly in relation to the level of social organization.

  18. Antibacterial drugs as corrosion inhibitors for bronze surfaces in acidic solutions

    NASA Astrophysics Data System (ADS)

    Rotaru, Ileana; Varvara, Simona; Gaina, Luiza; Muresan, Liana Maria

    2014-12-01

    The present study is aiming to investigate the effect of four antibiotics (amoxicillin, ciprofloxacin, doxycycline and streptomycin,) belonging to different classes of antibacterial drugs on bronze corrosion in a solution simulating an acid rain (pH 4). Due to their ability to form protective films on the metal surface, the tested antibiotics act as corrosion inhibitors for bronze. The antibiotics were tested at various concentrations in order to determine the optimal concentration range for the best corrosion inhibiting effect. In evaluating the inhibition efficiency, polarization curves, electrochemical impedance spectroscopy, SEM and XPS measurements were used. Moreover, a correlation between the inhibition efficiency of some antibacterial drugs and certain molecular parameters was determined by quantum chemical computations. Parameters like energies EHOMO and ELUMO and HOMO-LUMO energy gap were used for correlation with the corrosion data.

  19. Coca Leaf and Cocaine Addiction: Some Historical Notes

    PubMed Central

    Blejer-Prieto, H.

    1965-01-01

    Coca-leaf habituation has affected millions of Andean natives for over 400 years. In the last half-century it has also involved millions more Malayans. Coca leaf, from which cocaine and extracts for some commercial carbonated soft drinks are obtained, remains relatively unknown by the medical and allied professions elsewhere. A review of the original medical, historical and other pertinent literature of the last 350 years illustrates the origins of the use of coca leaf, its spread, the isolation of cocaine and its first uses, as well as some of the euphoric and other effects of both substances. PMID:5318484

  20. Neolithic and Bronze Age migration to Ireland and establishment of the insular Atlantic genome.

    PubMed

    Cassidy, Lara M; Martiniano, Rui; Murphy, Eileen M; Teasdale, Matthew D; Mallory, James; Hartwell, Barrie; Bradley, Daniel G

    2016-01-12

    The Neolithic and Bronze Age transitions were profound cultural shifts catalyzed in parts of Europe by migrations, first of early farmers from the Near East and then Bronze Age herders from the Pontic Steppe. However, a decades-long, unresolved controversy is whether population change or cultural adoption occurred at the Atlantic edge, within the British Isles. We address this issue by using the first whole genome data from prehistoric Irish individuals. A Neolithic woman (3343-3020 cal BC) from a megalithic burial (10.3× coverage) possessed a genome of predominantly Near Eastern origin. She had some hunter-gatherer ancestry but belonged to a population of large effective size, suggesting a substantial influx of early farmers to the island. Three Bronze Age individuals from Rathlin Island (2026-1534 cal BC), including one high coverage (10.5×) genome, showed substantial Steppe genetic heritage indicating that the European population upheavals of the third millennium manifested all of the way from southern Siberia to the western ocean. This turnover invites the possibility of accompanying introduction of Indo-European, perhaps early Celtic, language. Irish Bronze Age haplotypic similarity is strongest within modern Irish, Scottish, and Welsh populations, and several important genetic variants that today show maximal or very high frequencies in Ireland appear at this horizon. These include those coding for lactase persistence, blue eye color, Y chromosome R1b haplotypes, and the hemochromatosis C282Y allele; to our knowledge, the first detection of a known Mendelian disease variant in prehistory. These findings together suggest the establishment of central attributes of the Irish genome 4,000 y ago. PMID:26712024

  1. Colossal Above-Room-Temperature Metal—Insulator Switching of a Wadsley-type Tunnel Bronze

    SciTech Connect

    C Patridge; T Wu; G Sambandamurthy; S Banerjee

    2011-12-31

    We show evidence of the manifestation of enormous metal-insulator switching ranging up to almost six orders of magnitude in individual nanowires of {beta}'-Cu{sub x}V{sub 2}O{sub 5}. The magnitude and temperature of the phase transition is in strong contrast to data reported over several decades for other Wadsley-type mixed valence tunnel bronze structures.

  2. [Lead poisoning hazard in pewter manufacturing industry and in art bronze foundries (author's transl)].

    PubMed

    Carnevale, F; D'andrea, F; Grazioli, D

    1976-07-01

    Two manufacturing processes are reported by the authors, which proved to be sources of lead poisoning hazard, due to the presently employed row materials. The results of a survey performed in 50 pewter manufacturing workers, as well as in 16 workmen involved in artistic bronze melting, are also reported. The inspection of the manufacturing processes made it possible to find out the poison sources in both the above mentioned types of industry. PMID:1018573

  3. Neolithic and Bronze Age migration to Ireland and establishment of the insular Atlantic genome

    PubMed Central

    Cassidy, Lara M.; Martiniano, Rui; Murphy, Eileen M.; Teasdale, Matthew D.; Mallory, James; Hartwell, Barrie; Bradley, Daniel G.

    2016-01-01

    The Neolithic and Bronze Age transitions were profound cultural shifts catalyzed in parts of Europe by migrations, first of early farmers from the Near East and then Bronze Age herders from the Pontic Steppe. However, a decades-long, unresolved controversy is whether population change or cultural adoption occurred at the Atlantic edge, within the British Isles. We address this issue by using the first whole genome data from prehistoric Irish individuals. A Neolithic woman (3343–3020 cal BC) from a megalithic burial (10.3× coverage) possessed a genome of predominantly Near Eastern origin. She had some hunter–gatherer ancestry but belonged to a population of large effective size, suggesting a substantial influx of early farmers to the island. Three Bronze Age individuals from Rathlin Island (2026–1534 cal BC), including one high coverage (10.5×) genome, showed substantial Steppe genetic heritage indicating that the European population upheavals of the third millennium manifested all of the way from southern Siberia to the western ocean. This turnover invites the possibility of accompanying introduction of Indo-European, perhaps early Celtic, language. Irish Bronze Age haplotypic similarity is strongest within modern Irish, Scottish, and Welsh populations, and several important genetic variants that today show maximal or very high frequencies in Ireland appear at this horizon. These include those coding for lactase persistence, blue eye color, Y chromosome R1b haplotypes, and the hemochromatosis C282Y allele; to our knowledge, the first detection of a known Mendelian disease variant in prehistory. These findings together suggest the establishment of central attributes of the Irish genome 4,000 y ago. PMID:26712024

  4. New insight into the nature and properties of pale green surfaces of outdoor bronze monuments

    NASA Astrophysics Data System (ADS)

    Robbiola, L.; Rahmouni, K.; Chiavari, C.; Martini, C.; Prandstraller, D.; Texier, A.; Takenouti, H.; Vermaut, P.

    2008-07-01

    The present study concerns the chemical physical and electrochemical characterisations of the pale green surfaces formed on outdoor bronzes exposed in urban conditions. In the first part, results from investigations performed on the equestrian statue of the French king Louis XIV exposed in the Palace of Versailles (France) are given. Analyses by energy-dispersive spectrometry and Raman spectroscopy, coupled with scanning electron microscopy, show that the external layer is characterised by a marked selective dissolution of copper and zinc of the alloy leading to an important relative enrichment in tin compounds. The same phenomenon with the same magnitude, determined from dissolution factors fCu and fZn, has also been evidenced on other bronze monuments used for comparison. Proportionality between the amount of dissolved copper and zinc cations to their respective initial content in the alloy is evidenced independently of the tin content. The pale green patina appears to be a complex mixture of copper and tin compounds whose structure still needs to be more precisely characterised. In the second part, the electrochemical reactivity of tin compound enriched patina was investigated by cyclic voltammetry from a Cu10Sn electrode in sulfate solution at pH=2 and 5.6. This patina is stable at pH 5.6 but reactive at pH 2 in relation to the modification of properties of tin species in the patina. Mott Schottky application in pH 5.6 solution revealed that the bronze patina exhibits two types of semiconducting properties according to the potential domains, similar to what has been observed for pure tin in aqueous solutions. The destabilisation of bronze patinas in outdoor conditions and consequently the cyclic erosion due to rainfall have been attributed to the modification of tin species properties rather than to the transformation of copper compounds.

  5. Multifilamentary Nb{sub 3}Sn superconductors on the base of high-tin alloyed bronzes for high-field magnets

    SciTech Connect

    Sverdlov, V.Y.; Tikhonovsky, M.A.; Tikhinsky, G.F.; Kondratov, A.A.; Rudycheva, T.Y.; Klimenko, E.Y.; Novikov, S.I.

    1996-07-01

    Multifilamentary Nb{sub 3}Sn superconductors have been fabricated due to the worked out technology of deformed bronze with increased content of tin (16...18wt%) production. Studies have been made of the effects of bronze composition and thermal treatment conditions on the overall critical current density of multifilamentary Nb{sub 3}Sn superconductors. It is shown, that the use of the bronze with increased content of tin as well as bronze alloying with titanium improves the superconducting properties of composites, especially in high magnetic fields.

  6. Effect of Size Refinement and Distribution of the Lubricating Lead Phases in the Spray Forming High-Leaded Tin Bronze on Wear Rates

    NASA Astrophysics Data System (ADS)

    Yan, Pengfei; Wang, Deping; Yan, Biao; Mo, Fan

    2013-07-01

    Recently, the wear properties of high-leaded tin bronze were greatly concerned. In this work, the effect of size refinement and distribution of the lubricating lead phases in the spray forming (SF) high-leaded tin bronze on wear rates was studied by using scanning electron microscopy and sliding adhesive wear tests. It was observed that compared to the conventional casting bronze, the SF bronze features finer and more dispersed lead phases that formed more lubricating films in microstructure, which leads to the less wear rates.

  7. Band structure of the quasi two-dimensional purple molybdenum bronze

    NASA Astrophysics Data System (ADS)

    Guyot, H.; Balaska, H.; Perrier, P.; Marcus, J.

    2006-09-01

    The molybdenum purple bronze KMo 6O 17 is quasi two-dimensional (2D) metallic oxide that shows a Peierls transition towards a metallic charge density wave state. Since this specific transition is directly related to the electron properties of the normal state, we have investigated the electronic structure of this bronze at room temperature. The shape of the Mo K1s absorption edge reveals the presence of distorted MoO 6 octahedra in the crystallographic structure. Photoemission experiments evidence a large conduction band, with a bandwidth of 800 meV and confirm the metallic character of this bronze. A wide depleted zone separates the conduction band from the valence band that exhibits a fourfold structure, directly connected to the octahedral symmetry of the Mo sites. The band structure is determined by ARUPS in two main directions of the (0 0 1) Brillouin zone. It exhibits some unpredicted features but corroborates the earlier theoretical band structure and Fermi surface. It confirms the hidden one-dimensionality of KMo 6O 17 that has been proposed to explain the origin of the Peierls transition in this 2D compound.

  8. Properties and performance of fine-filament bronze-process Nb3Sn conductors

    NASA Technical Reports Server (NTRS)

    Walker, M. S.; Cutro, J. M.; Zeitlin, B. A.; Ozeryansky, G. M.; Schwall, R. E.; Oberly, C. E.; Ho, J. C.; Woollam, J. A.

    1979-01-01

    Fine-filament bronze-process Nb3Sn superconductors were fabricated to fulfill stringent requirements on critical current under tension in a one-inch bend diameter, current density, stability, and conductor losses. A large fraction of niobium filaments was incorporated in a bronze matrix, and a cable containing 4453 2-micron diameter filaments in each of six strands provided a current density of 85,000 A/sq cm at 10 to the -11th ohm-cm, 10 T, and 4.2 K. The next step was to incorporate copper stabilizer in a conductor with 20,538 filaments. These conductors, fabricated so that bend strains of about 1% would be experienced by the filaments in the one-inch bend, stably carried currents in the 200-500 A range. A quench current of 540 A in a 5-cm bend corresponds to 158,000 A/sq cm in the bronze and filament area, believed to be the highest critical current density reported for multifilamentary Nb3Sn.

  9. Improvement of critical current density of bronze processed Nb{sub 3}Sn superconducting wire

    SciTech Connect

    Miyazaki, T.; Fukumoto, Y.; Matsukura, N.

    1997-06-01

    Effects of tantalum addition to niobium filaments and tin contents in bronze matrix on the critical current density (J{sub c}) of Nb{sub 3}Sn superconducting wires manufactured by the bronze process were investigated in order to improve the J{sub c} in the high magnetic fields. In the results using the bronze composition of Cu-13wt.%Sn-0.3wt.%Ti, the J{sub c} shows a peak for 1 wt.% of tantalum content in the niobium filament. On the other hand, J{sub c} of samples with Cu-14wt.%Sn-0.3wt.%Ti is almost 1.7 times higher than that with Cu-13wt.%Sn-0.3wt.%Ti. From these findings, the authors manufactured a multifilamentary prototype (Nb,Ti,Ta){sub 3}Sn conductor made of Nb-1.0wt.%Ta and Cu-14wt.%Sn.0.3wt.%Ti. The non Cu J{sub c} of the conductor was 701 A/mm{sup 2} at 12 T and 51 A/mm{sup 2} at 21 T for the heat treatment temperature of 650{degrees} C.

  10. Evaluation of the inhibitive effect of benzotriazole on archeological bronze in acidic medium

    NASA Astrophysics Data System (ADS)

    Hassairi, Hèla; Bousselmi, Latifa; Khosrof, Slim; Triki, Ezzeddine

    2013-12-01

    An archaeological bronze artefact was a Punic coin excavated from the north east of Tunisia in 2001. The composition of the copper alloy revealed a content of 3.5 % of tin and 1.4 % of lead with the presence of some sulphur heterogeneity. The surface presents some roughnesses and cracks and is covered by a corrosion layer of 20-40 μm thickness. The use of benzotriazole (BTA) as an inhibitor has become a standard element for the preservation of cuprous-based metals. In order to investigate the behaviour of BTA in an acidic medium, an Electrochemical Impedance Spectroscopy (EIS) investigation was performed to characterize the electrochemical behaviour of the interface of the archaeological bronze sample/acidic medium without and with BTA addition. Impedance diagrams obtained at different immersion times show that the presence of the inhibitor prevents the diffusional process observed in the absence of BTA. The inhibition of the pre-polarized bronze surface revealed that the mechanism of action of the benzotriazole molecule in an acidic medium is governed by the chemisorption process.

  11. Density-functional studies of tungsten trioxide, tungsten bronzes, and related systems

    NASA Astrophysics Data System (ADS)

    Ingham, B.; Hendy, S. C.; Chong, S. V.; Tallon, J. L.

    2005-08-01

    Tungsten trioxide adopts a variety of structures which can be intercalated with charged species to alter the electronic properties, thus forming “tungsten bronzes.” Similar effects are observed upon removing oxygen from WO3 . We present a computational study of cubic and hexagonal alkali bronzes and examine the effects on cell size and band structure as the size of the intercalated ion is increased. With the exception of hydrogen (which is predicted to be unstable as an intercalate), the behavior of the bronzes are relatively consistent. NaWO3 is the most stable of the cubic systems, although in the hexagonal system the larger ions are more stable. The band structures are identical, with the intercalated atom donating its single electron to the tungsten 5d valence band. A study of fractional doping in the NaxWO3 system (0⩽x⩽1) showed a linear variation in cell parameter and a systematic shift in the Fermi level into the conduction band. In the oxygen-deficient WO3-x system the Fermi level undergoes a sudden jump into the conduction band at around x=0.2 . Lastly, three compounds of a layered WO4•α,ω -diaminoalkane hybrid series were studied and found to be insulating, with features in the band structure similar to those of the parent WO3 compound that relate well to experimental UV-visible spectroscopy results.

  12. Leaf absorbance and photosynthesis

    NASA Technical Reports Server (NTRS)

    Schurer, Kees

    1994-01-01

    The absorption spectrum of a leaf is often thought to contain some clues to the photosynthetic action spectrum of chlorophyll. Of course, absorption of photons is needed for photosynthesis, but the reverse, photosynthesis when there is absorption, is not necessarily true. As a check on the existence of absorption limits we measured spectra for a few different leaves. Two techniques for measuring absorption have been used, viz. the separate determination of the diffuse reflectance and the diffuse transmittance with the leaf at a port of an integrating sphere and the direct determination of the non-absorbed fraction with the leaf in the sphere. In a cross-check both methods yielded the same results for the absorption spectrum. The spectrum of a Fuchsia leaf, covering the short-wave region from 350 to 2500 nm, shows a high absorption in UV, blue and red, the well known dip in the green and a steep fall-off at 700 nm. Absorption drops to virtually zero in the near infrared, with subsequent absorptions, corresponding to the water absorption bands. In more detailed spectra, taken at 5 nm intervals with a 5 nm bandwidth, differences in chlorophyll content show in the different depths of the dip around 550 nm and in a small shift of the absorption edge at 700 nm. Spectra for Geranium (Pelargonium zonale) and Hibiscus (with a higher chlorophyll content) show that the upper limit for photosynthesis can not be much above 700 nm. No evidence, however, is to be seen of a lower limit for photosynthesis and, in fact, some experiments down to 300 nm still did not show a decrease of the absorption although it is well recognized that no photosynthesis results with 300 nm wavelengths.

  13. Elevated CO{sub 2} and leaf shape: Are dandelions getting toothier?

    SciTech Connect

    Thomas, S.C.; Bazzaz, F.A.

    1996-01-01

    Heteroblastic leaf development in Taraxacum officinale is compared between plants grown under ambient (350 ppm) vs. elevated (700 ppm) CO{sub 2} levels. Leaves of elevated CO{sub 2} plants exhibited more deeply incised leaf margins and relatively more slender leaf laminae than leaves of ambient CO{sub 2} plants. These differences were found to be significant in allometric analyses that controlled for differences in leaf size, as well as analyses that controlled for leaf development order. The effects of elevated CO{sub 2} on leaf shape were most pronounced when plants were grown individually, but detectable differences were also found in plants grown at high density. Although less dramatic than in Taraxacum, significant effects of elevated CO{sub 2} on leaf shape were also found in two other weedy rosette species, Plantago major and Rumex crispus. These observations support the long-standing hypothesis that leaf carbohydrate level plays an important role in regulating heteroblastic leaf development, though elevated CO{sub 2} may also affect leaf development through direct hormonal interactions or increased leaf water potential. In Taraxacum, pronounced modifications of leaf shape were found at CO{sub 2} levels predicted to occur within the next century. 33 refs., 5 figs.

  14. Autumn leaf subsidies influence spring dynamics of freshwater plankton communities.

    PubMed

    Fey, Samuel B; Mertens, Andrew N; Cottingham, Kathryn L

    2015-07-01

    While ecologists primarily focus on the immediate impact of ecological subsidies, understanding the importance of ecological subsidies requires quantifying the long-term temporal dynamics of subsidies on recipient ecosystems. Deciduous leaf litter transferred from terrestrial to aquatic ecosystems exerts both immediate and lasting effects on stream food webs. Recently, deciduous leaf additions have also been shown to be important subsidies for planktonic food webs in ponds during autumn; however, the inter-seasonal effects of autumn leaf subsidies on planktonic food webs have not been studied. We hypothesized that autumn leaf drop will affect the spring dynamics of freshwater pond food webs by altering the availability of resources, water transparency, and the metabolic state of ponds. We created leaf-added and no-leaf-added field mesocosms in autumn 2012, allowed mesocosms to ice-over for the winter, and began sampling the physical, chemical, and biological properties of mesocosms immediately following ice-off in spring 2013. At ice-off, leaf additions reduced dissolved oxygen, elevated total phosphorus concentrations and dissolved materials, and did not alter temperature or total nitrogen. These initial abiotic effects contributed to higher bacterial densities and lower chlorophyll concentrations, but by the end of spring, the abiotic environment, chlorophyll and bacterial densities converged. By contrast, zooplankton densities diverged between treatments during the spring, with leaf additions stimulating copepods but inhibiting cladocerans. We hypothesized that these differences between zooplankton orders resulted from resource shifts following leaf additions. These results suggest that leaf subsidies can alter both the short- and long-term dynamics of planktonic food webs, and highlight the importance of fully understanding how ecological subsidies are integrated into recipient food webs. PMID:25761444

  15. Genetic variability of Cotton leaf curl betasatellite in Northern India

    PubMed Central

    Sohrab, Sayed Sartaj; Azhar, Esam I.; Kamal, Mohammad A.; Bhattacharya, P.S.; Rana, D.

    2014-01-01

    Cotton is an important crop and its production is affected by various disease pathogens. Monopartite begomovirus associated betasatellites cause Cotton leaf curl disease (CLCuD) in Northern India. In order to access the occurrence and genetic variability of Cotton leaf curl betasatellites, an extensive field survey was conducted in states of Rajasthan, Punjab and Haryana. We selected the betasatellite sequence for analysis as they are reported as important for disease severity and sequence variability. Based on the field observations, the disease incidence ranged from 30% to 80% during the survey. Full genome and DNA β were amplified from various samples while no amplicon was obtained in some samples. The nucleotide sequence homology ranged from 90.0% to 98.7% with Cotton leaf curl virus (CLCuV), 55.2–55.5% with Bhendi yellow vein mosaic virus, 55.8% with Okra leaf curl virus and 51.70% with Tomato leaf curl virus isolates. The lowest similarity (47.8%) was found in CLCuV-Sudan isolate. Phylogenetic analysis showed that analyzed isolates formed a close cluster with various CLCuV isolates reported earlier. The analysis results show sequence variation in Cotton leaf curl betasatellite which could be the result of recombination. The results obtained by genome amplification and sequence variability indicate that some new variants are circulating and causing leaf curl disease in Rajasthan, Punjab and Haryana. PMID:25473373

  16. Genetic variability of Cotton leaf curl betasatellite in Northern India.

    PubMed

    Sohrab, Sayed Sartaj; Azhar, Esam I; Kamal, Mohammad A; Bhattacharya, P S; Rana, D

    2014-12-01

    Cotton is an important crop and its production is affected by various disease pathogens. Monopartite begomovirus associated betasatellites cause Cotton leaf curl disease (CLCuD) in Northern India. In order to access the occurrence and genetic variability of Cotton leaf curl betasatellites, an extensive field survey was conducted in states of Rajasthan, Punjab and Haryana. We selected the betasatellite sequence for analysis as they are reported as important for disease severity and sequence variability. Based on the field observations, the disease incidence ranged from 30% to 80% during the survey. Full genome and DNA β were amplified from various samples while no amplicon was obtained in some samples. The nucleotide sequence homology ranged from 90.0% to 98.7% with Cotton leaf curl virus (CLCuV), 55.2-55.5% with Bhendi yellow vein mosaic virus, 55.8% with Okra leaf curl virus and 51.70% with Tomato leaf curl virus isolates. The lowest similarity (47.8%) was found in CLCuV-Sudan isolate. Phylogenetic analysis showed that analyzed isolates formed a close cluster with various CLCuV isolates reported earlier. The analysis results show sequence variation in Cotton leaf curl betasatellite which could be the result of recombination. The results obtained by genome amplification and sequence variability indicate that some new variants are circulating and causing leaf curl disease in Rajasthan, Punjab and Haryana. PMID:25473373

  17. Simulations of Seasonal and Latitudinal Variations in Leaf Inclination Angle Distribution: Implications for Remote Sensing

    NASA Technical Reports Server (NTRS)

    Huemmrich, Karl F.

    2013-01-01

    The leaf inclination angle distribution (LAD) is an important characteristic of vegetation canopy structure affecting light interception within the canopy. However, LADs are difficult and time consuming to measure. To examine possible global patterns of LAD and their implications in remote sensing, a model was developed to predict leaf angles within canopies. Canopies were simulated using the SAIL radiative transfer model combined with a simple photosynthesis model. This model calculated leaf inclination angles for horizontal layers of leaves within the canopy by choosing the leaf inclination angle that maximized production over a day in each layer. LADs were calculated for five latitude bands for spring and summer solar declinations. Three distinct LAD types emerged: tropical, boreal, and an intermediate temperate distribution. In tropical LAD, the upper layers have a leaf angle around 35 with the lower layers having horizontal inclination angles. While the boreal LAD has vertical leaf inclination angles throughout the canopy. The latitude bands where each LAD type occurred changed with the seasons. The different LADs affected the fraction of absorbed photosynthetically active radiation (fAPAR) and Normalized Difference Vegetation Index (NDVI) with similar relationships between fAPAR and leaf area index (LAI), but different relationships between NDVI and LAI for the different LAD types. These differences resulted in significantly different relationships between NDVI and fAPAR for each LAD type. Since leaf inclination angles affect light interception, variations in LAD also affect the estimation of leaf area based on transmittance of light or lidar returns.

  18. Effects of leaf age within growth stages of pepper and sorghum plants on leaf thickness, water, chlorophyll, and light reflectance. [in spectral vegetation discrimination

    NASA Technical Reports Server (NTRS)

    Gausman, H. W.; Cardenas, R.; Berumen, A.

    1974-01-01

    Pepper and sorghum plants (characterized by porous and compact leaf mesophylls, respectively) were used to study the influence of leaf age on light reflectance. Measurements were limited to the upper five nodal positions within each growth stage, since upper leaves make up most of the reflectance surfaces remotely sensed. The increase in leaf thickness and water content with increasing leaf age was taken into consideration, since each of these factors affects the reflectance as well as the selection of spectral wavelength intervals for optimum discrimination of vegetation.

  19. Leaf development: a cellular perspective

    PubMed Central

    Kalve, Shweta; De Vos, Dirk; Beemster, Gerrit T. S.

    2014-01-01

    Through its photosynthetic capacity the leaf provides the basis for growth of the whole plant. In order to improve crops for higher productivity and resistance for future climate scenarios, it is important to obtain a mechanistic understanding of leaf growth and development and the effect of genetic and environmental factors on the process. Cells are both the basic building blocks of the leaf and the regulatory units that integrate genetic and environmental information into the developmental program. Therefore, to fundamentally understand leaf development, one needs to be able to reconstruct the developmental pathway of individual cells (and their progeny) from the stem cell niche to their final position in the mature leaf. To build the basis for such understanding, we review current knowledge on the spatial and temporal regulation mechanisms operating on cells, contributing to the formation of a leaf. We focus on the molecular networks that control exit from stem cell fate, leaf initiation, polarity, cytoplasmic growth, cell division, endoreduplication, transition between division and expansion, expansion and differentiation and their regulation by intercellular signaling molecules, including plant hormones, sugars, peptides, proteins, and microRNAs. We discuss to what extent the knowledge available in the literature is suitable to be applied in systems biology approaches to model the process of leaf growth, in order to better understand and predict leaf growth starting with the model species Arabidopsis thaliana. PMID:25132838

  20. 7 CFR 29.2528 - Leaf.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2528 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided unit of a whole leaf. ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.2528 Section 29.2528 Agriculture...

  1. Optimal Leaf Positions for SPAD Meter Measurement in Rice

    PubMed Central

    Yuan, Zhaofeng; Cao, Qiang; Zhang, Ke; Ata-Ul-Karim, Syed Tahir; Tian, Yongchao; Zhu, Yan; Cao, Weixing; Liu, Xiaojun

    2016-01-01

    The Soil Plant Analysis Development (SPAD) chlorophyll meter is one of the most commonly used diagnostic tools to measure crop nitrogen status. However, the measurement method of the meter could significantly affect the accuracy of the final estimation. Thus, this research was undertaken to develop a new methodology to optimize SPAD meter measurements in rice (Oryza sativa L.). A flatbed color scanner was used to map the dynamic chlorophyll distribution and irregular leaf shapes. Calculus algorithm was adopted to estimate the potential positions for SPAD meter measurement along the leaf blade. Data generated by the flatbed color scanner and SPAD meter were analyzed simultaneously. The results suggested that a position 2/3 of the distance from the leaf base to the apex (2/3 position) could represent the chlorophyll content of the entire leaf blade, as indicated by the relatively low variance of measurements at that position. SPAD values based on di-positional leaves and the extracted chlorophyll a and b contents were compared. This comparison showed that the 2/3 position on the lower leaves tended to be more sensitive to changes in chlorophyll content. Finally, the 2/3 position and average SPAD values of the fourth fully expanded leaf from the top were compared with leaf nitrogen concentration. The results showed the 2/3 position on that leaf was most suitable for predicting the nitrogen status of rice. Based on these results, we recommend making SPAD measurements at the 2/3 position on the fourth fully expanded leaf from the top. The coupling of dynamic chlorophyll distribution and irregular leaf shapes information can provide a promising approach for the calibration of SPAD meter measurement, which can further benefit the in situ nitrogen management by providing reliable estimation of crops nitrogen nutrition status. PMID:27303416

  2. Optimal Leaf Positions for SPAD Meter Measurement in Rice.

    PubMed

    Yuan, Zhaofeng; Cao, Qiang; Zhang, Ke; Ata-Ul-Karim, Syed Tahir; Tian, Yongchao; Zhu, Yan; Cao, Weixing; Liu, Xiaojun

    2016-01-01

    The Soil Plant Analysis Development (SPAD) chlorophyll meter is one of the most commonly used diagnostic tools to measure crop nitrogen status. However, the measurement method of the meter could significantly affect the accuracy of the final estimation. Thus, this research was undertaken to develop a new methodology to optimize SPAD meter measurements in rice (Oryza sativa L.). A flatbed color scanner was used to map the dynamic chlorophyll distribution and irregular leaf shapes. Calculus algorithm was adopted to estimate the potential positions for SPAD meter measurement along the leaf blade. Data generated by the flatbed color scanner and SPAD meter were analyzed simultaneously. The results suggested that a position 2/3 of the distance from the leaf base to the apex (2/3 position) could represent the chlorophyll content of the entire leaf blade, as indicated by the relatively low variance of measurements at that position. SPAD values based on di-positional leaves and the extracted chlorophyll a and b contents were compared. This comparison showed that the 2/3 position on the lower leaves tended to be more sensitive to changes in chlorophyll content. Finally, the 2/3 position and average SPAD values of the fourth fully expanded leaf from the top were compared with leaf nitrogen concentration. The results showed the 2/3 position on that leaf was most suitable for predicting the nitrogen status of rice. Based on these results, we recommend making SPAD measurements at the 2/3 position on the fourth fully expanded leaf from the top. The coupling of dynamic chlorophyll distribution and irregular leaf shapes information can provide a promising approach for the calibration of SPAD meter measurement, which can further benefit the in situ nitrogen management by providing reliable estimation of crops nitrogen nutrition status. PMID:27303416

  3. Plasticity in sunflower leaf and cell growth under high salinity.

    PubMed

    Céccoli, G; Bustos, D; Ortega, L I; Senn, M E; Vegetti, A; Taleisnik, E

    2015-01-01

    A group of sunflower lines that exhibit a range of leaf Na(+) concentrations under high salinity was used to explore whether the responses to the osmotic and ionic components of salinity can be distinguished in leaf expansion kinetics analysis. It was expected that at the initial stages of the salt treatment, leaf expansion kinetics changes would be dominated by responses to the osmotic component of salinity, and that later on, ion inclusion would impose further kinetics changes. It was also expected that differential leaf Na(+) accumulation would be reflected in specific changes in cell division and expansion rates. Plants of four sunflower lines were gradually treated with a relatively high (130 mm NaCl) salt treatment. Leaf expansion kinetics curves were compared in leaves that were formed before, during and after the initiation of the salt treatment. Leaf areas were smaller in salt-treated plants, but the analysis of growth curves did not reveal differences that could be attributed to differential Na(+) accumulation, since similar changes in leaf expansion kinetics were observed in lines with different magnitudes of salt accumulation. Nevertheless, in a high leaf Na(+) -including line, cell divisions were affected earlier, resulting in leaves with proportionally fewer cells than in a Na(+) -excluding line. A distinct change in leaf epidermal pavement shape caused by salinity is reported for the first time. Mature pavement cells in leaves of control plants exhibited typical lobed, jigsaw-puzzle shape, whereas in treated plants, they tended to retain closer-to-circular shapes and a lower number of lobes. PMID:24942979

  4. Selective dissolution in copper-tin alloys: Formation of corrosion- resistant patina on ancient Chinese bronze mirrors

    SciTech Connect

    Taube, M. |; Davenport, A.J.; King, A.H.; Chase, T. III

    1996-07-01

    Many ancient Chinese bronze mirrors have survived with a patina that leaves the delicate relief surface decorations intact. The microstructure of these ancient mirrors is two-phase and consists of acicular {alpha}-phase (Cu-rich) regions encased in a {delta}-phase (Sn-rich) matrix. At the surface, there is evidence of selective dissolution of the ct phase; the cc-phase regions are replaced pseudomorphically by a mineral product with the {delta} phase remaining metallic. Electrochemical polarization has been used to drive the copper dealloying process in modem, cast bronze. Synchrotron x-ray diffraction was employed to compare the ancient samples with those that were prepared potentiostatically. Poorly crystallized tin oxide (SnO{sub 2}) was found in the {alpha} replacement products of both sample types. The corrosion-resistance of the potentiostatically-treated bronze samples was tested by atmospheric exposure. Comparison with exposed, untreated samples indicated that the treatment was protective.

  5. A green route for microwave synthesis of sodium tungsten bronzes Na xWO 3 (0< x<1)

    NASA Astrophysics Data System (ADS)

    Guo, Juan; Dong, Cheng; Yang, Lihong; Fu, Guangcai

    2005-01-01

    A green route has been developed for microwave synthesis of sodium tungsten bronzes Na xWO 3 (0< x<1) from Na 2WO 4, WO 3 and tungsten powder. The hybrid microwave synthesis was carried out in argon atmosphere using CuO powder as the heating medium. Tungsten powder is used as the reducing agent instead of the alkali metal iodides previously used for the microwave synthesis of oxide bronzes. The prepared samples were characterized by powder X-ray diffraction, energy-dispersive X-ray analysis and scanning electron microscopy, and their phase constitutions, crystal structures and morphologies are in consistence with that in the literature. This synthesis method is simple, green and atom economic, and promising for preparation of other oxide bronzes and related compounds.

  6. The artificial leaf.

    PubMed

    Nocera, Daniel G

    2012-05-15

    To convert the energy of sunlight into chemical energy, the leaf splits water via the photosynthetic process to produce molecular oxygen and hydrogen, which is in a form of separated protons and electrons. The primary steps of natural photosynthesis involve the absorption of sunlight and its conversion into spatially separated electron-hole pairs. The holes of this wireless current are captured by the oxygen evolving complex (OEC) of photosystem II (PSII) to oxidize water to oxygen. The electrons and protons produced as a byproduct of the OEC reaction are captured by ferrodoxin of photosystem I. With the aid of ferrodoxin-NADP(+) reductase, they are used to produce hydrogen in the form of NADPH. For a synthetic material to realize the solar energy conversion function of the leaf, the light-absorbing material must capture a solar photon to generate a wireless current that is harnessed by catalysts, which drive the four electron/hole fuel-forming water-splitting reaction under benign conditions and under 1 sun (100 mW/cm(2)) illumination. This Account describes the construction of an artificial leaf comprising earth-abundant elements by interfacing a triple junction, amorphous silicon photovoltaic with hydrogen- and oxygen-evolving catalysts made from a ternary alloy (NiMoZn) and a cobalt-phosphate cluster (Co-OEC), respectively. The latter captures the structural and functional attributes of the PSII-OEC. Similar to the PSII-OEC, the Co-OEC self-assembles upon oxidation of an earth-abundant metal ion from 2+ to 3+, may operate in natural water at room temperature, and is self-healing. The Co-OEC also activates H(2)O by a proton-coupled electron transfer mechanism in which the Co-OEC is increased by four hole equivalents akin to the S-state pumping of the Kok cycle of PSII. X-ray absorption spectroscopy studies have established that the Co-OEC is a structural relative of Mn(3)CaO(4)-Mn cubane of the PSII-OEC, where Co replaces Mn and the cubane is extended in a

  7. Influence of heating rates on in situ resistance measurements of a bronze route Nb Sn Cu Ta multifilamentary conductor

    NASA Astrophysics Data System (ADS)

    Tan, K. S.; Hopkins, S. C.; Glowacki, B. A.

    2004-11-01

    The superconducting properties of a bronze process multifilamentary conductor are controlled by the structure, dimensions and composition of the intermetallic layers, which are strongly influenced by the details of the heat treatments applied to the conductor. It has previously been reported that the electrical resistivity of a Vacuumschmelze bronze process conductor varies during heat treatment, and that analysis of the conductor as a set of parallel resistors allows the features of the resistivity variation to be assigned to the progress of Nb 3Sn intermetallic phase formation. The behaviour of NSP2 Nb-Sn-Cu-Ta bronze process multifilamentary conductors (Imperial Metal Industries) is now reported as a function of the heating rate, in preparation for more complex non-isothermal heat treatment procedures. It is shown that the resistance of the wire measured in situ by an alternating current (AC) technique can be used to observe the progress of the formation of Nb 3Sn, and that the comparison of resistometric measurements at different heating rates can give an indication of other processes (such as recovery and recrystallisation) occurring at lower temperatures during the heating up process prior to isothermal annealing. In addition, this wire containing only about 1% of copper was carefully chosen because of the broken tantalum barriers around individual copper filaments. Therefore, the resistometric measurements were used to attempt to detect the diffusion of tin from the bronze matrix into the copper filaments at lower temperatures without noticeable influence on Nb 3Sn phase formation. Treating the NSP2 wire as a set of parallel resistors also permits estimates to be made of the intermetallic layer thicknesses from resistometric measurements, and these are shown to be in good agreement with estimates from scanning electron microscopy. The difference in critical temperature, Tc, between wires heated at different rates, with the presence of the bronze matrix and

  8. Nanoscale building blocks in a novel lithium arsenotungsten bronze: Synthesis and characterization

    SciTech Connect

    Zhao, Pei; Mangir Murshed, M.; Huq, Ashfia; Grossmann, Henrike K.; Mädler, Lutz; Alekseev, Evgeny V.; Gesing, Thorsten M.

    2015-03-15

    We report on a novel compound Li{sub 3}AsW{sub 7}O{sub 25} obtained by solid-state reaction and characterized by diffraction and spectroscopic methods. The bronze-type compound crystallizes in the orthorhombic space group Pbca with a=724.38(3) pm, b=1008.15(4) pm, c=4906.16(17) pm and Z=8. The structure is built up by chains of WO{sub 6} octahedra interconnected by AsO{sub 4} tetrahedra and WO{sub 6} octahedra forming a polyhedral arrangement as seen in intergrowth tungsten bronzes. The X-ray single crystal structure refinement allows solving the complex arsenotungstate framework. The powder neutron diffraction data analysis locates the lithium atoms. Thermal analysis showed that Li{sub 3}AsW{sub 7}O{sub 25} is stable up to its melting at 1135(3) K followed by a decomposition at 1182(5) K. The Kubelka–Munk treatment of the UV–vis spectrum revealed a wide band gap in the range of 2.84–3.40 eV depending on the presumed electron transition type. - Graphical abstract: Crystal structure of Li{sub 3}AsW{sub 7}O{sub 25} showing different schematic components. - Highlights: • A report on a novel compound Li{sub 3}AsW{sub 7}O{sub 25} obtained by solid-state reaction. • Chains and nano-blocks of WO{sub 6} octahedra and AsO{sub 4} tetrahedra formed a structure like intergrowth tungsten bronzes. • X-ray diffraction allowed solving the complex arsenotungstate framework. • Powder neutron diffraction data analysis locates the lithium atoms. • UV–vis spectrum revealed the band-gap.

  9. Exserohilum Leaf Spot on Tigergrass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tigergrass (Thysanolaena maxima (Roxb.) Kuntze ) is a popular ornamental grass grown throughout landscapes in South Florida. In the summer of 2006, a leaf spot was observed on tigergrass in the landscape and a commercial nursery in Homestead, FL. The causal agent of the leaf spot was isolated, cha...

  10. How to pattern a leaf

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf development presents a tremendous resource for tackling the question of patterning in biology. Leaves can be simple or highly dissected. They may have elaborated parts such as the tendrils of a pea leaf or the rolled blade of a carnivorous pitcher plant. Despite the variation in size, shape, an...

  11. Erosion of phosphor bronze under cavitation attack in a mineral oil

    NASA Technical Reports Server (NTRS)

    Rao, B. C. S.; Buckley, D. H.

    1986-01-01

    Experimental investigations on erosion of a copper alloy, phosphor bronze, under cavitation attack in a viscous mineral oil are presented. The details of pit formation and erosion were studied using scanning electron microscopy. The mean depth of penetration, the variations in surface roughness, and the changes in erosion pit size were studied. Cavitation pits formed initially over the grain boundaries while the surface grains were plastically deformed. Erosion of surface grains occurred largely by ductile fracture involving microcracking and removal in layers. The ratio h/a of the depth h to half width a of cavitation pits increased with test duration from 0.047 to 0.55.

  12. Tests of Lead-bronze Bearings in the DVL Bearing-testing Machine

    NASA Technical Reports Server (NTRS)

    Fischer, G

    1940-01-01

    The lead-bronze bearings tested in the DVL machine have proven themselves very sensitive to load changes as in comparison with bearings of light metal. In order to prevent surface injuries and consequently running interruptions, the increase of the load has to be made in small steps with sufficient run-in time between steps. The absence of lead in the running surface, impurities in the alloy (especially iron) and surface irregularities (pores) decreases the load-carrying capacity of the bearing to two or three times that of the static load.

  13. Failure analysis of nickel-aluminium-bronze sleeve valve in seawater effluent line

    SciTech Connect

    Islam, M.; Al-Hashem, A.; Carew, J. |

    1998-12-31

    Failure analysis of a Nickel-Aluminum-Bronze (NAB) sleeve valve in seawater effluent line of one of the refineries in Kuwait was conducted. Microscopic examination of the failed components, chemical analysis of valve material, identification of corrosion products, microstructural examination, microhardness tests and morphological examinations by the scanning electron microscope (SEM) were conducted to determine the cause of failure. Analysis of results indicated that the causes of failure can be attributed to a combination of erosion and cavitation corrosion as well as preferential phase corrosion of the alloy material. Cavitation corrosion resulted from operating the valve at or slightly below the critical cavitation index.

  14. Wear resistance of composite material made of eutectic steel and bronze powders

    SciTech Connect

    Mikulyak, O.V.; Shurin, A.K.

    1994-07-01

    The tribological properties of a hardened steel U8-composite pair in contact in which bronze is used as the matrix and eutectic alloy powder (steel 30 Kh13 with 15 wt.% VC of eutectic structure) is used as a filler are studied under conditions of reciprocal sliding friction without lubrication. Composite and counterbody wear is not uniform and depends on the amount of filler within the range 20-80%. A composite with 80% filler has good tribological properties and satisfactory lathe machining.

  15. PULSED EDDY CURRENT THICKNESS MEASUREMENT OF SELECTIVE PHASE CORROSION ON NICKEL ALUMINUM BRONZE VALVES

    SciTech Connect

    Krause, T. W.; Harlley, D.; Babbar, V. K.; Wannamaker, K.

    2010-02-22

    Nickel Aluminum Bronze (NAB) is a material with marine environment applications that under certain conditions can undergo selective phase corrosion (SPC). SPC involves the removal of minority elements while leaving behind a copper matrix. Pulsed eddy current (PEC) was evaluated for determination of SPC thickness on a NAB valve section with access from the surface corroded side. A primarily linear response of PEC amplitude, up to the maximum available SPC thickness of 4 mm was observed. The combination of reduced conductivity and permeability in the SPC phase relative to the base NAB was used to explain the observed sensitivity of PEC to SPC thickness variations.

  16. UV radiation is the primary factor driving the variation in leaf phenolics across Chinese grasslands.

    PubMed

    Chen, Litong; Niu, Kechang; Wu, Yi; Geng, Yan; Mi, Zhaorong; Flynn, Dan Fb; He, Jin-Sheng

    2013-11-01

    Due to the role leaf phenolics in defending against ultraviolet B (UVB) under previously controlled conditions, we hypothesize that ultraviolet radiation (UVR) could be a primary factor driving the variation in leaf phenolics in plants over a large geographic scale. We measured leaf total phenolics, ultraviolet-absorbing compounds (UVAC), and corresponding leaf N, P, and specific leaf area (SLA) in 151 common species. These species were from 84 sites across the Tibetan Plateau and Inner Mongolian grasslands of China with contrasting UVR (354 vs. 161 mW/cm(2) on average). Overall, leaf phenolics and UVAC were all significantly higher on the Tibetan Plateau than in the Inner Mongolian grasslands, independent of phylogenetic relationships between species. Regression analyses showed that the variation in leaf phenolics was strongly affected by climatic factors, particularly UVR, and soil attributes across all sites. Structural equation modeling (SEM) identified the primary role of UVR in determining leaf phenolic concentrations, after accounting for colinearities with altitude, climatic, and edaphic factors. In addition, phenolics correlated positively with UVAC and SLA, and negatively with leaf N and N: P. These relationships were steeper in the lower-elevation Inner Mongolian than on the Tibetan Plateau grasslands. Our data support that the variation in leaf phenolics is controlled mainly by UV radiation, implying high leaf phenolics facilitates the adaptation of plants to strong irradiation via its UV-screening and/or antioxidation functions, particularly on the Tibetan Plateau. Importantly, our results also suggest that leaf phenolics may influence on vegetation attributes and indirectly affect ecosystem processes by covarying with leaf functional traits. PMID:24363898

  17. UV radiation is the primary factor driving the variation in leaf phenolics across Chinese grasslands

    PubMed Central

    Chen, Litong; Niu, Kechang; Wu, Yi; Geng, Yan; Mi, Zhaorong; Flynn, Dan FB; He, Jin-Sheng

    2013-01-01

    Due to the role leaf phenolics in defending against ultraviolet B (UVB) under previously controlled conditions, we hypothesize that ultraviolet radiation (UVR) could be a primary factor driving the variation in leaf phenolics in plants over a large geographic scale. We measured leaf total phenolics, ultraviolet-absorbing compounds (UVAC), and corresponding leaf N, P, and specific leaf area (SLA) in 151 common species. These species were from 84 sites across the Tibetan Plateau and Inner Mongolian grasslands of China with contrasting UVR (354 vs. 161 mW/cm2 on average). Overall, leaf phenolics and UVAC were all significantly higher on the Tibetan Plateau than in the Inner Mongolian grasslands, independent of phylogenetic relationships between species. Regression analyses showed that the variation in leaf phenolics was strongly affected by climatic factors, particularly UVR, and soil attributes across all sites. Structural equation modeling (SEM) identified the primary role of UVR in determining leaf phenolic concentrations, after accounting for colinearities with altitude, climatic, and edaphic factors. In addition, phenolics correlated positively with UVAC and SLA, and negatively with leaf N and N: P. These relationships were steeper in the lower-elevation Inner Mongolian than on the Tibetan Plateau grasslands. Our data support that the variation in leaf phenolics is controlled mainly by UV radiation, implying high leaf phenolics facilitates the adaptation of plants to strong irradiation via its UV-screening and/or antioxidation functions, particularly on the Tibetan Plateau. Importantly, our results also suggest that leaf phenolics may influence on vegetation attributes and indirectly affect ecosystem processes by covarying with leaf functional traits. PMID:24363898

  18. Influence of temperature gradients on leaf water potential.

    PubMed

    Wiebe, H H; Prosser, R J

    1977-02-01

    Water potential was monitored at nine locations along single maize (Zea mays L.) leaf blades with aluminum block in situ thermocouple hygrometers. Water potential showed a continuous decrease toward the tip, with a 2- to 4-bar difference between leaf base and tip under both moist and dry soil conditions. The water potential difference between the soil and the leaf base was about 4 bars. Water potentials decreased during the day and during a drying cycle, and increased at night and after irrigation. Heating a band of a leaf to 40 C or cooling it to 7 C had no influence on the water potential of the affected portion when this was corrected for hygrometer output over standard calibrating solutions at the respective temperatures. Heating or cooling a portion of a leaf had neither short nor long term effects on water potential of more distal leaf portions continuously monitored by hygrometers in dew point readout. Water potential fluctuated with an amplitude of about 1.5 bars and an irregular period of 10 to 30 minutes. Measurements with silver foil in situ psychrometers gave similar results. PMID:16659828

  19. Influence of Temperature Gradients on Leaf Water Potential 1

    PubMed Central

    Wiebe, Herman H.; Prosser, Rex J.

    1977-01-01

    Water potential was monitored at nine locations along single maize (Zea mays L.) leaf blades with aluminum block in situ thermocouple hygrometers. Water potential showed a continuous decrease toward the tip, with a 2- to 4-bar difference between leaf base and tip under both moist and dry soil conditions. The water potential difference between the soil and the leaf base was about 4 bars. Water potentials decreased during the day and during a drying cycle, and increased at night and after irrigation. Heating a band of a leaf to 40 C or cooling it to 7 C had no influence on the water potential of the affected portion when this was corrected for hygrometer output over standard calibrating solutions at the respective temperatures. Heating or cooling a portion of a leaf had neither short nor long term effects on water potential of more distal leaf portions continuously monitored by hygrometers in dew point readout. Water potential fluctuated with an amplitude of about 1.5 bars and an irregular period of 10 to 30 minutes. Measurements with silver foil in situ psychrometers gave similar results. PMID:16659828

  20. Leaf hydraulics II: vascularized tissues.

    PubMed

    Rockwell, Fulton E; Holbrook, N Michele; Stroock, Abraham D

    2014-01-01

    Current models of leaf hydration employ an Ohm's law analogy of the leaf as an ideal capacitor, neglecting the resistance to flow between cells, or treat the leaf as a plane sheet with a source of water at fixed potential filling the mid-plane, neglecting the discrete placement of veins as well as their resistance. We develop a model of leaf hydration that considers the average conductance of the vascular network to a representative areole (region bounded by the vascular network), and represent the volume of tissue within the areole as a poroelastic composite of cells and air spaces. Solutions to the 3D flow problem are found by numerical simulation, and these results are then compared to 1D models with exact solutions for a range of leaf geometries, based on a survey of temperate woody plants. We then show that the hydration times given by these solutions are well approximated by a sum of the ideal capacitor and plane sheet times, representing the time for transport through the vasculature and tissue respectively. We then develop scaling factors relating this approximate solution to the 3D model, and examine the dependence of these scaling factors on leaf geometry. Finally, we apply a similar strategy to reduce the dimensions of the steady state problem, in the context of peristomatal transpiration, and consider the relation of transpirational gradients to equilibrium leaf water potential measurements. PMID:24012489

  1. Nanoscale building blocks in a novel lithium arsenotungsten bronze: Synthesis and characterization

    NASA Astrophysics Data System (ADS)

    Zhao, Pei; Mangir Murshed, M.; Huq, Ashfia; Grossmann, Henrike K.; Mädler, Lutz; Alekseev, Evgeny V.; Gesing, Thorsten M.

    2015-03-01

    We report on a novel compound Li3AsW7O25 obtained by solid-state reaction and characterized by diffraction and spectroscopic methods. The bronze-type compound crystallizes in the orthorhombic space group Pbca with a=724.38(3) pm, b=1008.15(4) pm, c=4906.16(17) pm and Z=8. The structure is built up by chains of WO6 octahedra interconnected by AsO4 tetrahedra and WO6 octahedra forming a polyhedral arrangement as seen in intergrowth tungsten bronzes. The X-ray single crystal structure refinement allows solving the complex arsenotungstate framework. The powder neutron diffraction data analysis locates the lithium atoms. Thermal analysis showed that Li3AsW7O25 is stable up to its melting at 1135(3) K followed by a decomposition at 1182(5) K. The Kubelka-Munk treatment of the UV-vis spectrum revealed a wide band gap in the range of 2.84-3.40 eV depending on the presumed electron transition type.

  2. Nanoscale building blocks in a novel lithium arsenotungsten bronze: Synthesis and characterization

    DOE PAGESBeta

    Zhao, Pei; Mangir Murshed, M.; Huq, Ashfia; Grossmann, Henrike K.; Mädler, Lutz; Alekseev, Evgeny V.; Gesing, Thorsten M.

    2015-02-19

    Here we report on a novel compound Li3AsW7O25 obtained by solid-state reaction and characterized by diffraction and spectroscopic methods. The bronze-type compound crystallizes in the orthorhombic space group Pbca with a=724.38(3) pm, b=1008.15(4) pm, c=4906.16(17) pm and Z=8. The structure is built up by chains of WO6 octahedra interconnected by AsO4 tetrahedra and WO6 octahedra forming a polyhedral arrangement as seen in intergrowth tungsten bronzes. The X-ray single crystal structure refinement allows solving the complex arsenotungstate framework. The powder neutron diffraction data analysis locates the lithium atoms. Thermal analysis showed that Li3AsW7O25 is stable up to its melting at 1135(3)more » K followed by a decomposition at 1182(5) K. Finally, the Kubelka-Munk treatment of the UV-vis spectrum revealed a wide band gap in the range of 2.84-3.40 eV depending on the presumed electron transition type.« less

  3. Magnetic properties of linear trimers in fluoride analogs of tetragonal tungsten bronze

    SciTech Connect

    Hong, Yaw-Shun; Boo, William O.J.; Mattern, Daniell L.

    2010-08-15

    The compounds KZnTiF{sub 6}, KZnVF{sub 6}, KVScF{sub 6}, KCrScF{sub 6}, and KMnScF{sub 6} are fluoride analogs of Tetragonal Tungsten Bronze. M{sup 2+}-M{sup 3+} ionic ordering in these fluorides provided systems which contained linear trinuclear complexes of their respective paramagnetic ions. Magnetic coupling within these linear trimers occurred below 100 K in each of the five systems. Derived magnetic susceptibility equations were fitted to observed magnetic susceptibilities for each of the possible spin systems: KZnTiF{sub 6} (S=1/2), J/k=-114 K; KZnVF{sub 6} (S=1), J/k=-39 K; KVScF{sub 6} (S=3/2), J/k=-16 K; KCrScF{sub 6} (S=2), J/k=-4 K; and KMnScF{sub 6} (S=5/2), J/k=-7.5 K. - Graphical abstract: Five fluoride analogs of Tetragonal Tungsten Bronze (KZnTiF{sub 6}, KZnVF{sub 6}, KVScF{sub 6}, KCrScF{sub 6}, and KMnScF{sub 6}) underwent M{sup 2+}-M{sup 3+} ionic ordering below 100 K, providing linear trinuclear complexes of their respective paramagnetic ions.

  4. The bronze shields found at the Ayanis fortress (Van region, Turkey): manufacturing techniques and corrosion phenomena

    NASA Astrophysics Data System (ADS)

    Ingo, G. M.; Çilingiroğlu, A.; Faraldi, F.; Riccucci, C.; Casaletto, M. P.; Erdem, A.; Batmaz, A.

    2010-09-01

    The manufacturing techniques, chemical composition and corrosion products grown on archaeological bronze shields found during the excavation of the Ayanis fortress (Lake Van region, Eastern Anatolia, Turkey) were studied by means of the combined use of scanning electron microscopy combined with energy dispersive spectrometry (SEM-EDS), X-ray diffraction (XRD) and optical microscopy (OM) techniques. The shields are dated back to 673-645 BC and in some cases are decorated with cuneiform inscriptions and ornaments representing various animals, such as lions and bulls. The micro-chemical and structural results show the presence of corrosion products constituted by copper carbonates (azurite and malachite), cuprite and dangerous chlorine-based compounds (nantokite, atacamite, clinoatacamite and paratacamite) due to the Cl-enriched soil of Ayanis. Furthermore, the results show that the bronze shields are coated with a Sn-enriched thin layer, likely due to an intentional tinning process carried out in ancient times to achieve a silver-like finish. Analytical data show an inter-granular corrosion phenomenon that heavily corroded the boundaries of the large equiassic grains inducing mechanical weakness. This latter phenomenon was induced by the repeated cycles of mechanical work and annealing thermal treatments carried out to restore the ductility and malleability of the alloy. Such processing caused the crystallisation and growth of the flattened grains, as well as impurities segregation phenomena along grain boundaries, thus enhancing the inter-granular long-term corrosion.

  5. A Roman bronze statuette with gilded silver mask from Sardinia: an EDXRF study

    NASA Astrophysics Data System (ADS)

    Cesareo, Roberto; Brunetti, Antonio; D'Oriano, Rubens; Canu, Alba; Demontis, Gonaria Mattia; Celauro, Angela

    2013-12-01

    A Roman bronze statuette from the 2nd Century BC was recovered from a nuragic sanctuary close to Florinas, in the north of Sardinia. The facial portion of the statuette is covered by a silver mask, partially gilded and attached to the bronze by tin-lead welding. The silver mask was carefully analyzed by portable energy-dispersive X-ray fluorescence (EDXRF), a non-destructive and non-invasive method. The aim of the analysis was to reconstruct the layered structure of the silver gilt mask, and to determine homogeneity and thickness of the gold, silver and lead-tin sheets. This is possible by using the internal ratio of the X-ray lines, i.e. starting from the surface, Au (L α/L β), Ag (K α/K β), Au-L α/Ag-K α and Pb (L α/L β).The results were compared with those obtained with simulated X-ray spectra, obtained both experimentally and by using the Monte Carlo simulation technique.

  6. Thermal conductance at millikelvin temperatures of woven ribbon cable with phosphor-bronze clad superconducting wires

    NASA Astrophysics Data System (ADS)

    Woodcraft, Adam L.; Ventura, Guglielmo; Martelli, Valentina; Holland, Wayne S.

    2010-08-01

    Woven Nomex® ribbon cables made up with superconducting niobium-titanium wire are used at millikelvin temperatures in many large cryogenic instruments. It is important to know how much heat in transmitted down such cables. However, the conductivity of the materials used is not well known. Another problem is that the wires are normally clad with alloys which exhibit some magnetism. This is a potential problem for instruments employing superconducting detectors. A safe non-magnetic alternative to the usual materials is phosphor-bronze clad niobium-titanium wiring. However, there is little experience with such wires. We have therefore measured the conductance of a ribbon cable made up with these wires. The measured values are in good agreement with our predictions, suggesting that the values we have used to model the cable are sufficiently accurate, and could therefore be used to predict the performance of ribbon cables using other cladding materials, so long as the conductivity of the cladding is reasonably well known. As part of our analysis, we consider the likely variation in thermal conductivity values for C51000 phosphor bronze caused by legitimate variations in composition.

  7. Comparing Compositions of Modern Cast Bronze Sculptures: Optical Emission Spectroscopy Versus x-Ray Fluorescence Spectroscopy

    NASA Astrophysics Data System (ADS)

    Young, M. L.; Dunand, D. C.

    2015-07-01

    Bulk elemental compositions of 74 modern cast bronze sculptures from the collection at the Art Institute of Chicago, the Philadelphia Museum of Art, and the Rodin Museum (Philadelphia, PA) were determined using inductively coupled plasma-optical emission spectroscopy (ICP-OES) and a handheld x-ray fluorescence (XRF) spectrometer. The elemental compositions of the cast sculptures as measured previously by ICP-OES and presently by XRF are compared: A good match is found between the two methods for the base metal (Cu) and the two majority alloying elements (Zn and Sn). For both ICP-OES and XRF data, when the Zn composition is plotted versus the Sn composition, three discernable clusters are found that are related to the artist, foundry, casting date, and casting method; they consist of (A) high-zinc brass, (B) low-zinc, low-tin brass, and (C) low-zinc, tin bronze. Thus, our study confirms that the relatively fast, nondestructive XRF spectrometry can be used effectively over slower and invasive, but more accurate, ICP-OES to help determine a sculpture's artist, foundry, date of creation, date of casting, and casting method.

  8. Nanoscale building blocks in a novel lithium arsenotungsten bronze: Synthesis and characterization

    SciTech Connect

    Zhao, Pei; Mangir Murshed, M.; Huq, Ashfia; Grossmann, Henrike K.; Mädler, Lutz; Alekseev, Evgeny V.; Gesing, Thorsten M.

    2015-02-19

    Here we report on a novel compound Li3AsW7O25 obtained by solid-state reaction and characterized by diffraction and spectroscopic methods. The bronze-type compound crystallizes in the orthorhombic space group Pbca with a=724.38(3) pm, b=1008.15(4) pm, c=4906.16(17) pm and Z=8. The structure is built up by chains of WO6 octahedra interconnected by AsO4 tetrahedra and WO6 octahedra forming a polyhedral arrangement as seen in intergrowth tungsten bronzes. The X-ray single crystal structure refinement allows solving the complex arsenotungstate framework. The powder neutron diffraction data analysis locates the lithium atoms. Thermal analysis showed that Li3AsW7O25 is stable up to its melting at 1135(3) K followed by a decomposition at 1182(5) K. Finally, the Kubelka-Munk treatment of the UV-vis spectrum revealed a wide band gap in the range of 2.84-3.40 eV depending on the presumed electron transition type.

  9. Vegetation development in the Middle Euphrates and Upper Jazirah (Syria/Turkey) during the Bronze Age

    NASA Astrophysics Data System (ADS)

    Deckers, Katleen; Pessin, Hugues

    2010-09-01

    Vegetation changes are reconstructed based on more than 51,000 charcoal fragments of more than 380 samples from nine Bronze Age sites in northern Syria and southern Turkey. In addition to fragment proportions, special attention was paid to the frequency of Pistacia relative to Quercus and Populus/ Salix relative to Tamarix, fruit-tree ubiquity, and riverine diversity in order to gain an improved understanding of the human versus climatic impact on the vegetation. The results indicate that human impacts first took place within the riverine forest. This phase was followed by land clearing within the woodland steppe, especially in the northern portion of the study area. In the south near Emar, the woodland steppe probably disappeared by the Late Bronze Age. It is uncertain whether this was caused by aridification and/or human clearing. The northward shift of the Pistacia-woodland steppe is very likely a result of climatic drying that occurred throughout the entire period under investigation. Although increased deforestation is evident through time, the small proportions of imported wood indicate that local resources were still available.

  10. Comparison of phosphor bronze metal sheet produced by twin roll casting and horizontal continuous casting

    NASA Astrophysics Data System (ADS)

    Hwang, J. D.; Li, B. J.; Hwang, W. S.; Hu, C. T.

    1998-08-01

    Much effort recently has been expended to study the strip casting process used to produce thin metal strip with a near final thickness. This process eliminates the need for hot rolling, consumes less energy, and offers a feasible method of producing various hard-to-shape alloys. The finer microstructure that results from the high cooling rate used during the casting process enhances mechanical properties. In this study, strips of phosphor bronzes (Cu-Sn-P) metal were produced using a twin roll strip casting process as well as a conventional horizontal continuous casting (HCC) process. The microstructures, macrosegregations, textures, and mechanical properties of the as-cast and as-rolled metal sheet produced by these two methods were examined carefully for comparative purposes. The results indicate that cast strip produced by a twin roll caster exhibit significantly less inverse segregation of tin compared to that produced by the HCC process. The mechanical properties including tensile strength, elongation, and microhardness of the products produced by the twin roll strip casting process are comparable to those of the HCC processed sheet. These properties meet specifications JIS H3110 and ASTM B 103M for commercial phosphor bronze sheet. The texture of the as-rolled sheet from these two processes, as measured from XRD pole figures, were found to be virtually the same, even though a significant difference exists between them in the as-cast condition.

  11. Structure and thermal expansion of the tungsten bronze Pb₂KNb₅O₁₅.

    PubMed

    Lin, Kun; Wu, Hui; Wang, Fangfang; Rong, Yangchun; Chen, Jun; Deng, Jinxia; Yu, Ranbo; Fang, Liang; Huang, Qingzhen; Xing, Xianran

    2014-05-21

    The structure and thermal expansion behavior of the tetragonal tungsten bronze oxide Pb2KNb5O15 were investigated by neutron powder diffraction and high-temperature X-ray diffraction. Below the Curie temperature, T(C) (orthorhombic phase, T(C) ≈ 460 °C), the cell parameters a and c increase with temperature, while b decreases. The thermal expansion coefficients are α(a) = 1.29 × 10(-5) °C(-1), α(b) = -1.56 × 10(-5) °C(-1), and α(c) = 1.62 × 10(-5) °C(-1). Temperature-dependent second harmonic generation (SHG), dielectric, and polarization-electrical field (P-E) hysteresis loop measurements were performed to study the symmetry and electric properties. We show that the distortion and cooperative rotation of NbO6 octahedrons are directly responsible for the negative thermal expansion coefficient along the polar b axis. It is suggested that Pb-O covalency, especially in the large and asymmetric pentagonal prisms, may be related to orthorhombic distortion and abnormal spontaneous polarization along the b axis. This study shows that tungsten bronze families are possible candidates for exploring negative thermal expansion materials. PMID:24622650

  12. The atmospheric corrosion of quaternary bronzes: An evaluation of the dissolution rate of the alloying elements

    NASA Astrophysics Data System (ADS)

    Bernardi, E.; Chiavari, C.; Martini, C.; Morselli, L.

    2008-07-01

    A comparative evaluation of the corrosion behaviour of a G85 bronze in acid rain solutions was performed. As weathering technique, a wet dry device was used to simulate a cyclic exposure to stagnant rain. The weathering solutions were a collected natural rain and an artificial solution reproducing the natural rain. The solutions were periodically monitored as concerns pH and metallic ion concentrations. On the aged specimens, surface studies were performed through OM, SEM and Raman analyses. At the end of weathering tests (40 days), weight loss measurements were carried out. The aim of this work was to examine the reproducibility in laboratory of the corrosive conditions determined by a natural acid rain. The final goal of this research is to investigate the dissolution of a quaternary alloy exposed to acid rains. The results showed slightly different corrosion behaviours as a consequence of the exposure to natural or synthetic rain. Concerning the mechanism of corrosion of G85 bronze, the innovative approach adopted in this study allowed one to point out the contribution of each alloying element to the general corrosion. Actually, while Cu and Pb progressively form insoluble corrosion compounds, Zn continuously dissolves, without forming detectable insoluble products. The absence of dissolved tin is remarkable.

  13. Leaf Relative Water Content Estimated from Leaf Reflectance and Transmittance

    NASA Technical Reports Server (NTRS)

    Vanderbilt, Vern; Daughtry, Craig; Dahlgren, Robert

    2016-01-01

    Remotely sensing the water status of plants and the water content of canopies remain long term goals of remote sensing research. In the research we report here, we used optical polarization techniques to monitor the light reflected from the leaf interior, R, as well as the leaf transmittance, T, as the relative water content (RWC) of corn (Zea mays) leaves decreased. Our results show that R and T both change nonlinearly. The result show that the nonlinearities cancel in the ratio R/T, which appears linearly related to RWC for RWC less than 90%. The results suggest that potentially leaf water status and perhaps even canopy water status could be monitored starting from leaf and canopy optical measurements.

  14. Regulation of Compound Leaf Development

    PubMed Central

    Wang, Yuan; Chen, Rujin

    2013-01-01

    Leaf morphology is one of the most variable, yet inheritable, traits in the plant kingdom. How plants develop a variety of forms and shapes is a major biological question. Here, we discuss some recent progress in understanding the development of compound or dissected leaves in model species, such as tomato (Solanum lycopersicum), Cardamine hirsuta and Medicago truncatula, with an emphasis on recent discoveries in legumes. We also discuss progress in gene regulations and hormonal actions in compound leaf development. These studies facilitate our understanding of the underlying regulatory mechanisms and put forward a prospective in compound leaf studies. PMID:27135488

  15. Investigation on corrosion stratigraphy and morphology in some Iron Age bronze alloys vessels by OM, XRD and SEM-EDS methods

    NASA Astrophysics Data System (ADS)

    Oudbashi, Omid; Hasanpour, Ata; Davami, Parviz

    2016-04-01

    The recently study of the corrosion in some bronze artefacts from the Sangtarashan Iron Age site, western Iran, was established to identify corrosion morphology and mechanism in these objects. The corrosion layers in 22 samples were studied by optical microscopy, scanning electron microscopy-energy-dispersive X-ray spectroscopy and X-ray diffraction methods. The results showed that a thin corrosion crust has formed on the surface of bronzes with a triple-layer structure, including two internal and one external corrosion layers. The formation of these layers is due to copper leaching from the bronze surface. The internal corrosion part has been a compact, tin-rich corrosion/oxidation product (noble patina) with some evidences from original metallurgical aspects of the bronze as well as a very thin layer beneath the tin-rich layer. External corrosion products have been identified as basic copper carbonates, malachite and azurite. Based on the results, the corrosion morphology in the Sangtarashan Iron Age bronzes is due to long-term burial in an appropriate environment in a moderately corrosive soil. Although it is the first time to investigate Iron Age bronzes from Iran, this corrosion morphology is partially similar to type I corrosion morphology observed in archaeological bronze objects; nevertheless, some deviations are visible in comparison with previously established patterns.

  16. Auxin Is Required for Leaf Vein Pattern in Arabidopsis1

    PubMed Central

    Sieburth, Leslie E.

    1999-01-01

    To investigate possible roles of polar auxin transport in vein patterning, cotyledon and leaf vein patterns were compared for plants grown in medium containing polar auxin transport inhibitors (N-1-naphthylphthalamic acid, 9-hydroxyfluorene-9-carboxylic acid, and 2,3,5-triiodobenzoic acid) and in medium containing a less well-characterized inhibitor of auxin-mediated processes, 2-(p-chlorophynoxy)-2-methylpropionic acid. Cotyledon vein pattern was not affected by any inhibitor treatments, although vein morphology was altered. In contrast, leaf vein pattern was affected by inhibitor treatments. Growth in polar auxin transport inhibitors resulted in leaves that lacked vascular continuity through the petiole and had broad, loosely organized midveins, an increased number of secondary veins, and a dense band of misshapen tracheary elements adjacent to the leaf margin. Analysis of leaf vein pattern developmental time courses suggested that the primary vein did not develop in polar auxin transport inhibitor-grown plants, and that the broad midvein observed in these seedlings resulted from the coalescence of proximal regions of secondary veins. Possible models for leaf vein patterning that could account for these observations are discussed. PMID:10594105

  17. Auxin is required for leaf vein pattern in Arabidopsis.

    PubMed

    Sieburth, L E

    1999-12-01

    To investigate possible roles of polar auxin transport in vein patterning, cotyledon and leaf vein patterns were compared for plants grown in medium containing polar auxin transport inhibitors (N-1-naphthylphthalamic acid, 9-hydroxyfluorene-9-carboxylic acid, and 2,3,5-triiodobenzoic acid) and in medium containing a less well-characterized inhibitor of auxin-mediated processes, 2-(p-chlorophynoxy)-2-methylpropionic acid. Cotyledon vein pattern was not affected by any inhibitor treatments, although vein morphology was altered. In contrast, leaf vein pattern was affected by inhibitor treatments. Growth in polar auxin transport inhibitors resulted in leaves that lacked vascular continuity through the petiole and had broad, loosely organized midveins, an increased number of secondary veins, and a dense band of misshapen tracheary elements adjacent to the leaf margin. Analysis of leaf vein pattern developmental time courses suggested that the primary vein did not develop in polar auxin transport inhibitor-grown plants, and that the broad midvein observed in these seedlings resulted from the coalescence of proximal regions of secondary veins. Possible models for leaf vein patterning that could account for these observations are discussed. PMID:10594105

  18. Peach leaf responses to soil and cement dust pollution.

    PubMed

    Maletsika, Persefoni A; Nanos, George D; Stavroulakis, George G

    2015-10-01

    Dust pollution can negatively affect plant productivity in hot, dry and with high irradiance areas during summer. Soil or cement dust were applied on peach trees growing in a Mediterranean area with the above climatic characteristics. Soil and cement dust accumulation onto the leaves decreased the photosynthetically active radiation (PAR) available to the leaves without causing any shade effect. Soil and mainly cement dust deposition onto the leaves decreased stomatal conductance, photosynthetic and transpiration rates, and water use efficiency due possibly to stomatal blockage and other leaf cellular effects. In early autumn, rain events removed soil dust and leaf functions partly recovered, while cement dust created a crust partially remaining onto the leaves and causing more permanent stress. Leaf characteristics were differentially affected by the two dusts studied due to their different hydraulic properties. Leaf total chlorophyll decreased and total phenol content increased with dust accumulation late in the summer compared to control leaves due to intense oxidative stress. The two dusts did not cause serious metal imbalances to the leaves, except of lower leaf K content. PMID:26054460

  19. Analyzing Lead Content in Ancient Bronze Coins by Flame Atomic Absorption Spectroscopy: An Archaeometry Laboratory with Nonscience Majors

    ERIC Educational Resources Information Center

    Donais, Mary Kate; Whissel, Greg; Dumas, Ashley; Golden, Kathleen

    2009-01-01

    A unique, interdisciplinary collaboration between chemistry and classics has led to the development of an experiment for nonscience majors. This instrumental analysis experiment was designed for use in an archaeology course to quantify the amount of lead in ancient bronze coins. The coins were corroded beyond visual identification, so provenance…

  20. Anomalously deep and fast failure of copper and bronze under the action of the corrosion products existing on them

    NASA Astrophysics Data System (ADS)

    Pozhidaeva, S. D.; Eliseeva, A. Yu.; Ivanov, A. M.

    2015-12-01

    When the corrosion products on copper and bronze are in close contact with a diluted aqueous solution of hydrochloric acid and atmospheric oxygen, they rapidly transform into effective metal (alloy) oxidizers, which provide rapid and deep metal consumption. The metal can be almost fully consumed in a reasonable technological time provided the accumulated solid phase of the products is periodically removed.

  1. Effect of transverse stress on the critical current of bronze-process and internal-tin Nb sub 3 Sn

    SciTech Connect

    Ekin, J.W.; Bray, S.L.; Bahn, W.L. )

    1991-04-15

    The effect of transverse stress on the critical current of two substantially different Nb{sub 3}Sn superconductors, a bronze-process conductor and an internal-tin conductor, has been measured. Photomicrographs of the two conductors reveal a basic difference in their microstructure. The bronze-process conductor exhibits columnar grains that are radially oriented within the Nb{sub 3}Sn filaments, while the grains of the internal-tin conductor are more equiaxed and randomly oriented. The radial orientation of the bronze-process grains defines an anisotropy between the axial and transverse directions that might account for the greater sensitivity of the critical current to transverse stress reported previously. The effect of transverse stress measured on the internal-tin conductor, however, is comparable to that of the bronze-process conductor. Thus, these data indicate that the transverse stress effect is not highly dependent on either grain morphology or fabrication process. From an engineering standpoint the similarity of the transverse stress effect for these two types of Nb{sub 3}Sn superconductors represents an important simplification for setting first-order quantitative limits on the mechanical design of large superconducting magnets.

  2. Transverse stress effect on the critical current of internal tin and bronze process Nb{sub 3}Sn superconductors

    SciTech Connect

    Ekin, J.W.; Bray, S.L.; Danielson, P.; Smathers, D.; Sabatini, R.L.; Suenaga, M.

    1989-12-31

    The effect of transverse stress on the critical current density, J{sub c}, has been shown to be significant in bronze process Nb{sub 3}Sn, with the onset of significant degradation at about 50 Mpa. In an applied field of 10 T, the magnitude of the effect is about seven times larger for transverse stress than for axial tensile stress. In a subsequent study, similar results were observed in another bronze process Nb{sub 3}Sn conductor made by a different manufacturer. The mechanism accounting for the transverse stress effect and its large magnitude compared with the axial tensile effect is still the subject of speculation. In an attempt to better understand the nature of the effect, The authors have undertaken a series of experiments to determine whether the transverse stress effect depends on the grain morphology of the Nb{sub 3}Sn reaction layer in the superconductor. To do this, the authors have measured the effect in an internal tin conductor with excess tin, which yields a more equiaxed Nb{sub 3}Sn grain morphology than for bronze process Nb{sub 3}Sn, where the grains are more columnar. The results for the effect of transverse compression on the J{sub c} of a round bronze process Nb{sub 3}Sn wire are given. The data are probably applicable to a wide variety of Nb{sub 3}Sn conductors for magnet engineering.

  3. Copper and tin isotopic analysis of ancient bronzes for archaeological investigation: development and validation of a suitable analytical methodology.

    PubMed

    Balliana, Eleonora; Aramendía, Maite; Resano, Martin; Barbante, Carlo; Vanhaecke, Frank

    2013-03-01

    Although in many cases Pb isotopic analysis can be relied on for provenance determination of ancient bronzes, sometimes the use of "non-traditional" isotopic systems, such as those of Cu and Sn, is required. The work reported on in this paper aimed at revising the methodology for Cu and Sn isotope ratio measurements in archaeological bronzes via optimization of the analytical procedures in terms of sample pre-treatment, measurement protocol, precision, and analytical uncertainty. For Cu isotopic analysis, both Zn and Ni were investigated for their merit as internal standard (IS) relied on for mass bias correction. The use of Ni as IS seems to be the most robust approach as Ni is less prone to contamination, has a lower abundance in bronzes and an ionization potential similar to that of Cu, and provides slightly better reproducibility values when applied to NIST SRM 976 Cu isotopic reference material. The possibility of carrying out direct isotopic analysis without prior Cu isolation (with AG-MP-1 anion exchange resin) was investigated by analysis of CRM IARM 91D bronze reference material, synthetic solutions, and archaeological bronzes. Both procedures (Cu isolation/no Cu isolation) provide similar δ (65)Cu results with similar uncertainty budgets in all cases (±0.02-0.04 per mil in delta units, k = 2, n = 4). Direct isotopic analysis of Cu therefore seems feasible, without evidence of spectral interference or matrix-induced effect on the extent of mass bias. For Sn, a separation protocol relying on TRU-Spec anion exchange resin was optimized, providing a recovery close to 100 % without on-column fractionation. Cu was recovered quantitatively together with the bronze matrix with this isolation protocol. Isotopic analysis of this Cu fraction provides δ (65)Cu results similar to those obtained upon isolation using AG-MP-1 resin. This means that Cu and Sn isotopic analysis of bronze alloys can therefore be carried out after a single chromatographic

  4. 7 CFR 29.3036 - Leaf surface.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf surface. 29.3036 Section 29.3036 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Leaf surface. The smoothness or roughness of the web or lamina of a tobacco leaf. Leaf surface...

  5. 7 CFR 29.3525 - Leaf.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Type 95) § 29.3525 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.3525 Section 29.3525 Agriculture Regulations... Practices), DEPARTMENT OF AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS...

  6. 7 CFR 29.1028 - Leaf.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Type 92) § 29.1028 Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.1028 Section 29.1028 Agriculture Regulations... Practices), DEPARTMENT OF AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS...

  7. 7 CFR 29.3033 - Leaf.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Leaf. Whole, unstemmed leaf. Leaf, when applied to tobacco in strip form, shall describe the divided... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf. 29.3033 Section 29.3033 Agriculture Regulations... Practices), DEPARTMENT OF AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS...

  8. 7 CFR 29.3036 - Leaf surface.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 2 2011-01-01 2011-01-01 false Leaf surface. 29.3036 Section 29.3036 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... Leaf surface. The smoothness or roughness of the web or lamina of a tobacco leaf. Leaf surface...

  9. Do we Underestimate the Importance of Leaf Size in Plant Economics? Disproportional Scaling of Support Costs Within the Spectrum of Leaf Physiognomy

    PubMed Central

    Niinemets, Ülo; Portsmuth, Angelika; Tena, David; Tobias, Mari; Matesanz, Silvia; Valladares, Fernando

    2007-01-01

    Background Broad scaling relationships between leaf size and function do not take into account that leaves of different size may contain different fractions of support in petiole and mid-rib. Methods The fractions of leaf biomass in petiole, mid-rib and lamina, and the differences in chemistry and structure among mid-ribs, petioles and laminas were investigated in 122 species of contrasting leaf size, life form and climatic distribution to determine the extent to which differences in support modify whole-lamina and whole-leaf structural and chemical characteristics, and the extent to which size-dependent support investments are affected by plant life form and site climate. Key Results For the entire data set, leaf fresh mass varied over five orders of magnitude. The percentage of dry mass in mid-rib increased strongly with lamina size, reaching more than 40 % in the largest laminas. The whole-leaf percentage of mid-rib and petiole increased with leaf size, and the overall support investment was more than 60 % in the largest leaves. Fractional support investments were generally larger in herbaceous than in woody species and tended to be lower in Mediterranean than in cool temperate and tropical plants. Mid-ribs and petioles had lower N and C percentages, and lower dry to fresh mass ratio, but greater density (mass per unit volume) than laminas. N percentage of lamina without mid-rib was up to 40 % higher in the largest leaves than the total-lamina (lamina and mid-rib) N percentage, and up to 60 % higher than whole-leaf N percentage, while lamina density calculated without mid-rib was up to 80 % less than that with the mid-rib. For all leaf compartments, N percentage was negatively associated with density and dry to fresh mass ratio, while C percentage was positively linked to these characteristics, reflecting the overall inverse scaling between structural and physiological characteristics. However, the correlations between N and C percentages and structural

  10. Near infrared leaf reflectance modeling

    NASA Technical Reports Server (NTRS)

    Parrish, J. B.

    1985-01-01

    Near infrared leaf reflectance modeling using Fresnel's equation (Kumar and Silva, 1973) and Snell's Law successfully approximated the spectral curve for a 0.25-mm turgid oak leaf lying on a Halon background. Calculations were made for ten interfaces, air-wax, wax-cellulose, cellulose-water, cellulose-air, air-water, and their inverses. A water path of 0.5 mm yielded acceptable results, and it was found that assignment of more weight to those interfaces involving air versus water or cellulose, and less to those involving wax, decreased the standard deviation of the error for all wavelengths. Data suggest that the air-cell interface is not the only important contributor to the overall reflectance of a leaf. Results also argue against the assertion that the near infrared plateau is a function of cell structure within the leaf.

  11. Increasing leaf hydraulic conductance with transpiration rate minimizes the water potential drawdown from stem to leaf

    PubMed Central

    Simonin, Kevin A.; Burns, Emily; Choat, Brendan; Barbour, Margaret M.; Dawson, Todd E.; Franks, Peter J.

    2015-01-01

    Leaf hydraulic conductance (k leaf) is a central element in the regulation of leaf water balance but the properties of k leaf remain uncertain. Here, the evidence for the following two models for k leaf in well-hydrated plants is evaluated: (i) k leaf is constant or (ii) k leaf increases as transpiration rate (E) increases. The difference between stem and leaf water potential (ΔΨstem–leaf), stomatal conductance (g s), k leaf, and E over a diurnal cycle for three angiosperm and gymnosperm tree species growing in a common garden, and for Helianthus annuus plants grown under sub-ambient, ambient, and elevated atmospheric CO2 concentration were evaluated. Results show that for well-watered plants k leaf is positively dependent on E. Here, this property is termed the dynamic conductance, k leaf(E), which incorporates the inherent k leaf at zero E, which is distinguished as the static conductance, k leaf(0). Growth under different CO2 concentrations maintained the same relationship between k leaf and E, resulting in similar k leaf(0), while operating along different regions of the curve owing to the influence of CO2 on g s. The positive relationship between k leaf and E minimized variation in ΔΨstem–leaf. This enables leaves to minimize variation in Ψleaf and maximize g s and CO2 assimilation rate over the diurnal course of evaporative demand. PMID:25547915

  12. Increasing leaf hydraulic conductance with transpiration rate minimizes the water potential drawdown from stem to leaf.

    PubMed

    Simonin, Kevin A; Burns, Emily; Choat, Brendan; Barbour, Margaret M; Dawson, Todd E; Franks, Peter J

    2015-03-01

    Leaf hydraulic conductance (k leaf) is a central element in the regulation of leaf water balance but the properties of k leaf remain uncertain. Here, the evidence for the following two models for k leaf in well-hydrated plants is evaluated: (i) k leaf is constant or (ii) k leaf increases as transpiration rate (E) increases. The difference between stem and leaf water potential (ΔΨstem-leaf), stomatal conductance (g s), k leaf, and E over a diurnal cycle for three angiosperm and gymnosperm tree species growing in a common garden, and for Helianthus annuus plants grown under sub-ambient, ambient, and elevated atmospheric CO₂ concentration were evaluated. Results show that for well-watered plants k leaf is positively dependent on E. Here, this property is termed the dynamic conductance, k leaf(E), which incorporates the inherent k leaf at zero E, which is distinguished as the static conductance, k leaf(0). Growth under different CO₂ concentrations maintained the same relationship between k leaf and E, resulting in similar k leaf(0), while operating along different regions of the curve owing to the influence of CO₂ on g s. The positive relationship between k leaf and E minimized variation in ΔΨstem-leaf. This enables leaves to minimize variation in Ψleaf and maximize g s and CO₂ assimilation rate over the diurnal course of evaporative demand. PMID:25547915

  13. Leaf life span spectrum of tropical woody seedlings: effects of light and ontogeny and consequences for survival

    PubMed Central

    Kitajima, Kaoru; Cordero, Roberto A.; Wright, S. Joseph

    2013-01-01

    Background and Aims Leaf life span is widely recognized as a key life history trait associated with herbivory resistance, but rigorous comparative data are rare for seedlings. The goal of this study was to examine how light environment affects leaf life span, and how ontogenetic development during the first year may influence leaf fracture toughness, lamina density and stem density that are relevant for herbivory resistance, leaf life span and seedling survival. Methods Data from three experiments encompassing 104 neotropical woody species were combined. Leaf life span, lamina and vein fracture toughness, leaf and stem tissue density and seedling survival were quantified for the first-year seedlings at standardized ontogenetic stages in shade houses and common gardens established in gaps and shaded understorey in a moist tropical forest in Panama. Mortality of naturally recruited seedlings till 1 year later was quantified in 800 1-m2 plots from 1994 to 2011. Key Results Median leaf life span ranged widely among species, always greater in shade (ranging from 151 to >1790 d in the understorey and shade houses) than in gaps (115–867 d), but with strong correlation between gaps and shade. Leaf and stem tissue density increased with seedling age, whereas leaf fracture toughness showed only a weak increase. All these traits were positively correlated with leaf life span. Leaf life span and stem density were negatively correlated with seedling mortality in shade, while gap mortality showed no correlation with these traits. Conclusions The wide spectrum of leaf life span and associated functional traits reflects variation in shade tolerance of first-year seedlings among coexisting trees, shrubs and lianas in this neotropical forest. High leaf tissue density is important in enhancing leaf toughness, a known physical defence, and leaf life span. Both seedling leaf life span and stem density should be considered as key functional traits that contribute to seedling survival

  14. Differential responses of ammonia/ammonium-oxidizing microorganisms in mangrove sediment to amendment of acetate and leaf litter.

    PubMed

    Wang, Yong-Feng; Li, Xiao-Yan; Gu, Ji-Dong

    2014-04-01

    The effects of acetate and leaf litter powder on ammonia/ammonium-oxidizing microorganisms (AOMs) in mangrove sediment were investigated in a laboratory incubation study for a period of 60 days. The results showed that different AOMs responded differently to the addition of acetate and leaf litter. A higher diversity of anaerobic ammonium-oxidizing (anammox) bacteria was observed when acetate or leaf litter was added than the control. However, acetate and leaf litter generally inhibited the growth of anammox bacteria despite that leaf litter promoted their growth in the first 5 days. The inhibitory effects on anammox bacteria were more pronounced by acetate than by leaf litter. Neither acetate nor leaf litter affected ammonia-oxidizing archaea (AOA) community structures, but promoted their growth. For ammonia-oxidizing bacteria (AOB), the addition of acetate or leaf litter resulted in changes of community structures and promoted their growth in the early phase of the incubation. In addition, the promoting effects by leaf litter on AOB growth were more obvious than acetate. These results indicated that organic substances affect AOM community structures and abundances. The study suggests that leaf litter has an important influence on the community structures and abundances of AOMs in mangrove sediment and affects the nitrogen cycle in such ecosystem. PMID:24169949

  15. Settlement and landscape history of the Northern Franconian Jura during the Bronze and Iron Ages

    NASA Astrophysics Data System (ADS)

    Kothieringer, Katja; Lambers, Karsten; Seregély, Timo; Schäfer, Andreas

    2014-05-01

    This paper describes the results of initial archaeological and geoarchaeological fieldwork in the Northern Franconian Jura between the cities of Bayreuth and Bamberg. Our research aims at the reconstruction of settlement patterns and strategies of land use during the Metal Ages (Bronze Age and Iron Age) in the catchment area of the river Weismain. The project is designed as a case study for research into the settlement and landscape history of a rural region of the Central German Uplands during the last two millennia before our era. During the Bronze Age and Iron Age (about 2.100 BC to 30 BC), the Northern Franconian Jura must have been densely populated, as evidenced by numerous burial monuments, prominent hillforts like the Staffelberg, and ritual places on the Jurassic plateau. However, little is known about small rural settlements and hamlets which would have accounted for most of the settlement activity in the region. Thus, we lack the most important element for understanding the cultural history and development of the region as well as the consequences of human impact on the landscape. This impact must have induced changes in vegetation and subsequent erosion processes, leading to the formation of geoarchives like colluvial layers. During our initial fieldwork we identified such colluvial layers in depressions on the Jurassic plateau or at footslope positions. As radiocarbon datings of charcoal fragments showed, some of them date from the Metal Ages. The type is wood of these charcoal fragments is oak, which recently only occurs sporadically in mixed forests with beeches. The quantification of the shift of sediments from the plateau to the valleys will be the next important step of geoarchaeological research. Thus, investigations both on the plateau and in the river valleys will accompany archaeological survey. Apart from landscape reconstruction, they will also provide information on the state of preservation and the conditions for identifying archaeological

  16. GPR Surveys for Archaeological Investigation in a Bronze Age site from NW Portugal

    NASA Astrophysics Data System (ADS)

    Gonçalves, L.; Sampaio, H. A.; Bettencourt, A. M. S.; Alves, M. I. C.

    2012-04-01

    This work describes the use of Ground-penetrating Radar (GPR) surveys in the identification and mapping of subtle cultural remains, from Pego Late Bronze Age settlement, located near the city of Braga, in NW Portugal. Bronze Age settlements from NW Portugal are characterized by the presence archaeological structures such as storage pits, postholes and trenches. These subtle structures have a very low dielectric contrast, making them quite difficult to detect in GPR surveys. In the case of Pego Site, previous investigations using conventional archaeological techniques, during a rescue excavation, partially revealed a residential area, a necropolis, and a stockade foundation trench that encircle the whole settlement. Different GPR prospection approaches were performed using GSSI Sir 3000 System, with 400 MHz antennae, with the objective of identify and define the borders between the different areas of human occupation inside the settlement. For the GPR survey, a grid-based approach with closely spaced parallels transects was defined, covering different areas inside the site. A first survey was conducted with a pseudo-3D methodology, with 50 cm profile separation, followed by a second survey with a dense data acquisition methodology, with 10 cm profile separation. Processed two-dimensional GPR profiles and constructed amplituded-slice maps were produced and analysed. Wave velocities were determined by reflected wave methods and by Hyperbola-Fitting method. The background analysis of the archaeological and geological features of the site, integrated with the preliminary interpretation of GPR data (profiles and amplitude slice-maps) suggest the presence of flat graves, in the west part of the site, and storage pits, post holes and some small trenches, in the centre and north area of the settlement. This interpretation indicates that the settlement is individualized in two different areas, a necropolis and a residential area, such as the first archaeological study

  17. Interpreting chlorophyll fluorescence signals: the effects of leaf age

    NASA Astrophysics Data System (ADS)

    Albert, L.; Vergeli, P.; Martins, G.; Saleska, S. R.; Huxman, T. E.

    2015-12-01

    Remote sensing of sun-induced chlorophyll fluorescence (SIF) promises robust estimation of carbon uptake across landscapes, as studies of plant physiology have shown that fluorescence emission is directly linked to photosynthesis at the leaf level. Yet most leaf-level studies demonstrating the link between chlorophyll fluorescence and photosynthesis have studied leaves in their prime: leaves that recently finished expansion and have yet to senesce. By contrast, remote sensing of landscapes involves observing leaves of different ages. For example, broadleaf deciduous forests and annual plant communities in temperate regions have leaves that develop and then senesce over the course of a growing season. In this experiment, we explored how leaf age and moisture availability affect steady-state fluoresence (Fs) at the leaf level. We simultaneously measured net photosynthesis (Anet) and Fs for leaves of known ages on greenhouse-grown dwarf Helianthus Annuus (sunflowers) from two watering treatments. To monitor plant water status, we measured pre-dawn water potential, and, for a subset of leaves, osmotic potential. Fully expanded or near-fully expanded leaves (~8 to ~23 days old) had higher Anet at saturating light than young, expanding leaves (less than 8 days old) or old leaves nearing senescence (>23 days old). We found a positive relationship between Fs and Anet, suggesting that the link between fluorescence emission and photosynthesis is robust across leaves of different ages. However, leaf age had marked effects on the light response curve of photosynthesis and fluorescence metrics. These results suggest that leaf age distribution, and changes in leaf age distribution due to phenology, should be considered when interpreting SIF at the landscape level.

  18. Dielectric properties of tetragonal tungsten bronze films deposited by RF magnetron sputtering

    NASA Astrophysics Data System (ADS)

    Bodeux, Romain; Michau, Dominique; Josse, Michaël; Maglione, Mario

    2014-12-01

    Tetragonal tungsten bronze (TTB) films have been synthesised on Pt(111)/TiO2/SiO2/Si substrates from Ba2LnFeNb4O15 ceramics (Ln = La, Nd, Eu) by RF magnetron sputtering. X-ray diffraction measurements evidenced the multi-oriented nature of films with some degrees of preferential orientation along (111). The dependence of the dielectric properties on temperature and frequency has been investigated. The dielectric properties of the films are similar to those of the bulk, i.e., ɛ ˜150 and σ ˜10-6 Ω-1 cm-1 at 1 MHz and room temperature. The films exhibit two dielectric anomalies which are attributed to Maxwell Wagner polarization mechanism and relaxor behaviour. Both anomalies are sensitive to post-annealing under oxygen atmosphere and their activation energies are similar Ea ˜0.30 eV. They are explained in terms of electrically heterogeneous contributions in the films.

  19. Towards novel multiferroic and magnetoelectric materials: dipole stability in tetragonal tungsten bronzes

    PubMed Central

    Rotaru, Andrei; Miller, Andrew J.; Arnold, Donna C.; Morrison, Finlay D.

    2014-01-01

    We discuss the strategy for development of novel functional materials with the tetragonal tungsten bronze structure. From the starting composition Ba6GaNb9O30, the effect of A- and B-site substitutions on the dielectric properties is used to develop an understanding of the origin and stability of the dipolar response in these compounds. Both tetragonal strain induced by large B-site cations and local strain variations created by isovalent A-site substitutions enhance dipole stability but result in a dilute, weakly correlated dipolar response and canonical relaxor behaviour. Decreasing cation size at the perovskite A2-site increases the dipolar displacements in the surrounding octahedra, but insufficiently to result in dipole ordering. Mechanisms introducing small A-site lanthanide cations and incorporation of A-site vacancies to induce ferroelectricity and magnetism are presented. PMID:24421377

  20. Electronic Structures of Purple Bronze KMo6O17 Studied by X-Ray Photoemission Spectra

    NASA Astrophysics Data System (ADS)

    Qin, Xiaokui; Wei, Junyin; Shi, Jing; Tian, Mingliang; Chen, Hong; Tian, Decheng

    X-ray photoemission spectroscopy study has been performed for the purple bronze KMo6O17. The structures of conduction band and valence band are analogous to the results of ultraviolet photoemission spectra and are also consistent with the model of Travaglini et al., but the gap between conduction and valence band is insignificant. The shape of asymmetric and broadening line of O-1s is due to unresolved contributions from the many inequivalent oxygen sites in this crystal structure. Mo 3d core-level spectrum reveals that there are two kinds of valence states of Molybdenum (Mo+5 and Mo+6). The calculated average valence state is about +5.6, which is consistent with the expectation value from the composition of this material. The tail of Mo-3d spectrum toward higher binding energy is the consequence of the excitation of electron-hole pairs with singularity index of 0.21.

  1. Investigation on Deformation Behavior of Nickel Aluminum Bronze by Neutron Diffraction and Transmission Electron Microscopy

    NASA Astrophysics Data System (ADS)

    Xu, Xiaoyan; Wang, Hong; Lv, Yuting; Lu, Weijie; Sun, Guangai

    2016-05-01

    The deformation behavior, deformation microstructures, and generated inter-phase stresses of nickel aluminum bronze were investigated by in situ neutron diffraction instrument and transmission electron microscopy in this paper. Lattice strains calculated by both peak shifting and broadening by Gaussian fitting of α and κ phase neutron diffraction peak profiles at both holding stress conditions and unloaded stress conditions were compared. Twining and stacking faults in α matrix were observed after deformed by different tensile stresses. Compressive internal/residual stress in α matrix and tensile internal stress in κ phase in elasto-plastic region were calculated based on neutron diffraction analysis. The piled-up dislocations around hard κ phases increase with increasing the deformation degree, which raise the stress concentration near α/ κ interface and increase the internal stresses.

  2. Qualitative and quantitative laser-induced breakdown spectroscopy of bronze objects

    NASA Astrophysics Data System (ADS)

    Tankova, V.; Blagoev, K.; Grozeva, M.; Malcheva, G.; Penkova, P.

    2016-03-01

    Laser-induced breakdown spectroscopy (LIBS) is an analytical technique for qualitative and quantitative elemental analysis of solids, liquids and gases. In this work, the method was applied for investigation of archaeological bronze objects. The analytical information obtained by LIBS was used for qualitative determination of the elements in the material used for manufacturing of the objects under study. Quantitative chemical analysis was also performed after generating calibration curves with standard samples of similar matrix composition. Quantitative estimation of the elemental concentration of the bulk of the samples was performed, together with investigation of the surface layer of the objects. The results of the quantitative analyses gave indications about the manufacturing process of the investigated objects.

  3. Evaluation of copper, aluminum bronze, and copper-nickel for YMP [Yucca Mountain Project] container material

    SciTech Connect

    Kass, J.N.

    1989-05-01

    In this presentation, I will discuss our evaluation of the materials copper, 7% aluminum bronze, and 70/30 copper-nickel. These are three of the six materials currently under consideration as potential waste-packaging materials. I should mention that we are also considering alternatives to these six materials. This work is part of the Yucca Mountain Project (YMP), formerly known as the Nevada Nuclear Waste Storage Investigations (NNWSI) Project. The expected-case environment in our proposed vault is quite different from that encountered at the WIPP site or that expected in a Canadian vault. Our proposed site is under a desert mountain, Yucca Mountain, in southern Nevada. The repository itself will be located approximately 700 feet above the water table and 300 to 1200 feet below the surface of the mountain. The variations in these numbers are due to the variations in mountain topography.

  4. Rapid climate change did not cause population collapse at the end of the European Bronze Age

    PubMed Central

    Armit, Ian; Swindles, Graeme T.; Becker, Katharina; Plunkett, Gill; Blaauw, Maarten

    2014-01-01

    The impact of rapid climate change on contemporary human populations is of global concern. To contextualize our understanding of human responses to rapid climate change it is necessary to examine the archeological record during past climate transitions. One episode of abrupt climate change has been correlated with societal collapse at the end of the northwestern European Bronze Age. We apply new methods to interrogate archeological and paleoclimate data for this transition in Ireland at a higher level of precision than has previously been possible. We analyze archeological 14C dates to demonstrate dramatic population collapse and present high-precision proxy climate data, analyzed through Bayesian methods, to provide evidence for a rapid climatic transition at ca. 750 calibrated years B.C. Our results demonstrate that this climatic downturn did not initiate population collapse and highlight the nondeterministic nature of human responses to past climate change. PMID:25404290

  5. Evidence for bronze age cannibalism in El Mirador Cave (Sierra de Atapuerca, Burgos, Spain).

    PubMed

    Cáceres, Isabel; Lozano, Marina; Saladié, Palmira

    2007-07-01

    During excavations of the Bronze Age levels at El Mirador Cave, a hole containing human remains was found. Taphonomic analysis revealed the existence of cutmarks, human toothmarks, cooking damage, and deliberate breakage in most of the remains recovered, suggesting a clear case of gastronomic cannibalism. The piled distribution of the remains, the uneven skeletal representation, and the chronological difference between the pit and the remains suggest that these bones were subsequently buried by a human group that inhabited into the cave later in time. Evidence of gastronomic cannibalism has already been documented in Gran Dolina, another site in the Sierra de Atapuerca, on remains of Homo antecessor with an age of 800 ky (Fernández-Jalvo et al.: Science 271 (1996) 277-278; Fernández-Jalvo et al.: J Hum Evol 37 (1999) 591-622). PMID:17492670

  6. Rapid climate change did not cause population collapse at the end of the European Bronze Age.

    PubMed

    Armit, Ian; Swindles, Graeme T; Becker, Katharina; Plunkett, Gill; Blaauw, Maarten

    2014-12-01

    The impact of rapid climate change on contemporary human populations is of global concern. To contextualize our understanding of human responses to rapid climate change it is necessary to examine the archeological record during past climate transitions. One episode of abrupt climate change has been correlated with societal collapse at the end of the northwestern European Bronze Age. We apply new methods to interrogate archeological and paleoclimate data for this transition in Ireland at a higher level of precision than has previously been possible. We analyze archeological (14)C dates to demonstrate dramatic population collapse and present high-precision proxy climate data, analyzed through Bayesian methods, to provide evidence for a rapid climatic transition at ca. 750 calibrated years B.C. Our results demonstrate that this climatic downturn did not initiate population collapse and highlight the nondeterministic nature of human responses to past climate change. PMID:25404290

  7. BaiKhao (rice leaf) app: a mobile device-based application in analyzing the color level of the rice leaf for nitrogen estimation

    NASA Astrophysics Data System (ADS)

    Intaravanne, Yuttana; Sumriddetchkajorn, Sarun

    2012-11-01

    As the color level of the rice leaf corresponds to the nitrogen status of rice in the field, farmers use a leaf color chart (LCC) to identify the color level of the rice leaf in order to estimate the amount of N fertilizer needed for the rice field. However, the ability of the farmers and degeneration of the LCC color affect the accuracy in reading the rice leaf color level. In this paper, we propose a mobile device-based rice leaf color analyzer called "BaiKhao" (means rice leaf in Thai). Our key idea is to simultaneously capture and process the two-dimensional (2-D) data scattered and reflected from the rice leaf and its surrounding reference, thus eliminating expensive external components and alleviating the environmental fluctuation but yet achieving a high accuracy. Our field tests using an Android-based mobile phone show that all important leaf color levels of 1, 2, 3, and 4 can be correctly identified. Additional key features include low cost and ease of implementation with highly efficient distribution through the internet.

  8. Are leaf chemistry signatures preserved at the canopy level?

    SciTech Connect

    Borel, C.C.; Gerstl, S.A.W.

    1994-05-01

    Imaging spectrometers have the potential to be very useful in remote sensing of canopy chemistry constituents such as nitrogen and lignin. In this study under the HIRIS project the question of how leaf chemical composition which is reflected in leaf spectral features in the reflectance and transmittance is affected by canopy architecture was investigated. Several plants were modeled with high fidelity and a radiosity model was used to compute the canopy spectral signature over the visible and near infrared. We found that chemical constituent specific signatures such as absorptions are preserved and in the case of low absorption are actually enhanced. For moderately dense canopies the amount of a constituent depends also on the total leaf area.

  9. Erosion of tungsten and its brazed joints with bronze irradiated by pulsed deuterium plasma flows

    NASA Astrophysics Data System (ADS)

    Yakushin, V.; Polsky, V.; Kalin, B.; Dzhumaev, P.; Polyansky, A.; Sevryukov, O.; Suchkov, A.; Fedotov, V.

    2013-11-01

    This work presents results on erosion of mono- and polycrystalline tungsten and its brazed joints with bronze substrates under irradiation by high-temperature pulsed (τp ˜ 20 μs) deuterium plasma flows, with a power density q = 19-66 GW/m2 and pulses numbering from 2 to 10, simulating the expected plasma disruptions and ELMs in fusion reactors. The surface erosion and heat resistance of tungsten and brazed joints were investigated by scanning electron microscopy, and erosion coefficients were determined by target mass loss. It is found that for both types of tungsten the surface starts to significantly crack even under relatively weak irradiation regimes (q = 19 GW/m2, N = 2), at which point surface melting is not observed. Local melting becomes visible with an increase of q up to 25 GW/m2. In addition, there is formation of blisters with a typical size of 1-2 μm on the surface of monocrystalline samples and craters up to 2 μm in diameter on polycrystalline samples. In addition, craters ˜10-30 μm in diameter are formed on defects similar to those observed under unipolar arcs. At that point, the erosion coefficients change to within ranges of 0.2-0.7 × 10-5 kg/J m2. It is found that at q = 50 GW/m2, the brazed joints of monocrystalline tungsten with bronze of Cu-0.6% Cr-0.08% Zr have the highest heat resistance.

  10. Strain Rate Dependency of Bronze Metal Matrix Composite Mechanical Properties as a Function of Casting Technique

    NASA Astrophysics Data System (ADS)

    Brown, Lloyd; Joyce, Peter; Radice, Joshua; Gregorian, Dro; Gobble, Michael

    2012-07-01

    Strain rate dependency of mechanical properties of tungsten carbide (WC)-filled bronze castings fabricated by centrifugal and sedimentation-casting techniques are examined, in this study. Both casting techniques are an attempt to produce a functionally graded material with high wear resistance at a chosen surface. Potential applications of such materials include shaft bushings, electrical contact surfaces, and brake rotors. Knowledge of strain rate-dependent mechanical properties is recommended for predicting component response due to dynamic loading or impact events. A brief overview of the casting techniques for the materials considered in this study is followed by an explanation of the test matrix and testing techniques. Hardness testing, density measurement, and determination of the volume fraction of WC particles are performed throughout the castings using both image analysis and optical microscopy. The effects of particle filling on mechanical properties are first evaluated through a microhardness survey of the castings. The volume fraction of WC particles is validated using a thorough density survey and a rule-of-mixtures model. Split Hopkinson Pressure Bar (SHPB) testing of various volume fraction specimens is conducted to determine strain dependence of mechanical properties and to compare the process-property relationships between the two casting techniques. The baseline performances of C95400 bronze are provided for comparison. The results show that the addition of WC particles improves microhardness significantly for the centrifugally cast specimens, and, to a lesser extent, in the sedimentation-cast specimens, largely because the WC particles are more concentrated as a result of the centrifugal-casting process. Both metal matrix composites (MMCs) demonstrate strain rate dependency, with sedimentation casting having a greater, but variable, effects on material response. This difference is attributed to legacy effects from the casting process, namely

  11. Biological affinities and adaptations of Bronze Age Bactrians: IV. A craniometric investigation of Bactrian origins.

    PubMed

    Hemphill, B E

    1999-02-01

    Discovery of a previously unknown Bronze Age civilization (Oxus civilization) centered on the oases of Central Asia revealed the presence of large, preplanned urban centers immediately above sterile soil. Given the absence of local antecedents, the sudden appearance and proliferation of these Oxus civilization urban centers in the oases of Bactria and Margiana immediately raised the issue of where the inhabitants of these urban centers came from. Three hypotheses have been offered by archaeologists to account for the origins of Oxus civilization populations. These include the early influence model, the late colonization model, and the trichotomy model. Eleven craniometric variables from 12 Aeneolithic and Bronze Age samples, encompassing 657 adults from Central Asia, Iran, and the Indus Valley, are compared to test which if any of these hypotheses are supported by the pattern of phenetic affinities possessed by the Oxus civilization inhabitants of the north Bactrian oasis. Craniometric differences between samples are compared with Mahalanobis generalized distance (d2), and patterns of phenetic affinity are assessed with two types of cluster analysis (WPGMA, neighbor-joining method), multidimensional scaling, and principal coordinates analysis. Results of this analysis provide no support for either the late colonization model or the trichotomy model but do offer some support for the early influence model. Nevertheless, it is clear that the early influence model fails to account for a shift in interregional contacts, perhaps from western China to the north around 2000 BC, that appears to have played a major role in the origins of the Oxus civilization inhabitants of the north Bactrian oasis. PMID:9988380

  12. Bronze age cosmology and rock art images. Solar ships, deer and charts

    NASA Astrophysics Data System (ADS)

    Dimitriadis, G.

    Bronze Age societies were technologically complex. The impressive production of metal artefacts embodies clearly their astronomical culture and cosmological viewpoint. Same ascertainment is valid also for rock art. In fact, around the European landscape were discovered several cliffs engraved with solar ships, deer and charts. How one could be interpret them? Which is the hidden mentality? From the end of 3rd millennium-early 2nd millennium B. C. deep technological transformations are made by metals. New inventions such metal extraction for weapon production, horse pulling chariot used for war and the bull pulling one used for trade may shorten the culture and material distances between Central Europe and South Mediterranean area. Indeed, taphonomic studies indicate a specific modification of the human body mortuary traditional disposition (orientated to significant astronomical targets) below a substantial transformation of mortuary apparatus with spot evidence of weapons (halberds, swords, knifes) and ornaments (double spiral, lunar shape pectorals). The famous Trundhold Solar chart, the 2nd millennium terracotta chart form Dupljaja, the solar boats petroglyph in Bohusland and the horse rider carved on Philippi's cliffs were conceived by the same mentality: communion with the divinity. Culture expressions as communicate manifestation attested in rock art were produced by the same mentality presented in Bronze Age art-crafts such as, 1. Culture epidemiologic patterns dispersion took place through out iconographic motives, and, 2. Animals can play a double face function inside an analogical-mythological system: a. animal-reflex; b. animal-agent. The question is: Could such petroglyphs help us to "read" archaeoastronomical properly in an archaeological site?

  13. Functional relationships of leafing intensity to plant height, growth form and leaf habit

    NASA Astrophysics Data System (ADS)

    Yan, En-Rong; Milla, Rubén; Aarssen, Lonnie W.; Wang, Xi-Hua

    2012-05-01

    Leafing intensity, i.e. the number of leaves per unit of stem volume or mass, is a common developmental correlate of leaf size. However, the ecological significance and the functional implications of variation in leafing intensity, other than its relation to leaf size, are unknown. Here, we explore its relationships with plant height, growth form, leaf size, and leaf habit to test a series of corollaries derived from the leafing intensity premium hypothesis. Volume-based leafing intensities and plant heights were recorded for 109 woody species from the subtropical evergreen broadleaf forests of eastern China. In addition, we compiled leafing intensity data from published literature, and combined it with our data to form a 398 species dataset, to test for differences of leafing intensity between plant growth forms (i.e. herbaceous and woody) and leaf habits (i.e. deciduous and evergreens). Leafing intensity was negatively correlated with plant height and individual leaf mass. Volume-based leafing intensities were significantly higher in herbaceous species than in woody species, and also higher in deciduous than in evergreen woody species. In conclusion, leafing intensity relates strongly to plant height, growth form, leaf size, and leaf habit in directions generally in accordance to the leafing intensity premium hypothesis. These results can be interpreted in terms of the evolution of adaptive strategies involving response to herbivory, competitive ability for light and reproductive economy.

  14. How to pattern a leaf.

    PubMed

    Bolduc, N; O'Connor, D; Moon, J; Lewis, M; Hake, S

    2012-01-01

    Leaf development presents a tremendous resource for tackling the question of patterning in biology. Leaves can be simple or highly dissected. They may have elaborated parts such as the tendrils of a pea leaf or the rolled blade of a carnivorous pitcher plant. Despite the variation in size, shape, and function, all leaves initiate in the same manner: from the flanks of a meristem. The maize leaf is useful for analysis of patterning due to the wealth of mutants and the distinct tissues along the proximal distal axis. The blade is distal, the sheath is proximal, and the ligule forms at the blade/sheath boundary. Establishment of this boundary involves the transcription factors LIGULELESS1 and LIGULELESS2 and the kinase LIGULELESS NARROW. The meristem-specific protein KNOTTED1 (KN1) binds and modulates the lg2 gene. Given the localization of KN1 at the proximal end of the leaf from the time of inception, we hypothesize that KN1 has a role in establishing the very proximal end of the leaf, whereas an auxin maximum guides the growing distal tip. PMID:23174765

  15. Factors Affecting Survival of Bacteriophage on Tomato Leaf Surfaces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The ability of bacteriophage to persist in the phyllosphere for extended periods is limited by many factors, including sunlight irradiation, especially in the UV zone, temperature, desiccation, and exposure to copper bactericides. The effects of these factors on persistence of phage and formulated p...

  16. Intra- and inter-community variation in leaf water repellency along a 4000 m elevation transect in the Peruvian Andes

    NASA Astrophysics Data System (ADS)

    Goldsmith, G. R.; Doughty, C.; Bentley, L. P.; Shenkin, A.; Castro-Ccoscco, R. M.; Salinas, N.; Malhi, Y.

    2014-12-01

    Leaf water repellency is a measure of the hydrophobicity, or wettability, of leaf surfaces. At the scale of the plant, leaf water repellency can affect gas exchange, nutrient exchange, and pathogen growth. At the scale of the ecosystem, it can affect canopy water storage, throughfall, and evaporation. To date, very few studies have measured intra- and inter- community variation in leaf water repellency of tropical forest ecosystems. In the context of a broad survey of plant functional traits, we measured leaf water repellency in nine forest plots occurring across a 4000 m elevation gradient in the eastern Andes of Peru. Observed angles of incidence (63 ± 13°) indicate high leaf wettability, with no significant difference between sun and shade leaves. In contrast with previous research along elevation gradients, we find no strong evidence for variation across sites, but rather find high variation within a given site. Finally, we find that leaf water repellency may be predicted using sunlit leaf spectra with a low RMSE (<25% of the mean), indicating that future research on leaf water repellency could be carried out using high resolution hyperspectral remote sensing. As the climate of tropical ecosystems changes, the resultant changes in leaf water repellency will impact plants, communities and ecosystems. Our results inform our understanding of where and to what extent these impacts are most likely to occur.

  17. Leafing out phenology in woody plants of the Northern Hempisphere show phylogenetic, ecological and anatomical patterns

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leafing out phenology affects a wide variety of ecosystem processes and ecological interactions, and it affects how natural and artificial ecosystems respond to different weather conditions in the spring. There is, however, relatively little information available on the factors affecting species dif...

  18. Biophysical control of leaf temperature

    NASA Astrophysics Data System (ADS)

    Dong, N.; Prentice, I. C.; Wright, I. J.

    2014-12-01

    In principle sunlit leaves can maintain their temperatures within a narrower range than ambient temperatures. This is an important and long-known (but now overlooked) prediction of energy balance theory. Net radiation at leaf surface in steady state (which is reached rapidly) must be equal to the combination of sensible and latent heat exchanges with surrounding air, the former being proportional to leaf-to-air temperature difference (ΔT), the latter to the transpiration rate. We present field measurements of ΔT which confirm the existence of a 'crossover temperature' in the 25-30˚C range for species in a tropical savanna and a tropical rainforest environment. This finding is consistent with a simple representation of transpiration as a function of net radiation and temperature (Priestley-Taylor relationship) assuming an entrainment factor (ω) somewhat greater than the canonical value of 0.26. The fact that leaves in tropical forests are typically cooler than surrounding air, often already by solar noon, is consistent with a recently published comparison of MODIS day-time land-surface temperatures with air temperatures. Theory further predicts a strong dependence of leaf size (which is inversely related to leaf boundary-layer conductance, and therefore to absolute magnitude of ΔT) on moisture availability. Theoretically, leaf size should be determined by either night-time constraints (risk of frost damage to active leaves) or day-time constraints (risk of heat stress damage),with the former likely to predominate - thereby restricting the occurrence of large leaves - at high latitudes. In low latitudes, daytime maximum leaf size is predicted to increase with temperature, provided that water is plentiful. If water is restricted, however, transpiration cannot proceed at the Priestley-Taylor rate, and it quickly becomes advantageous for plants to have small leaves, which do not heat up much above the temperature of their surroundings. The difference between leaf

  19. Dynamic secondary ion mass spectrometry and X-ray photoelectron spectroscopy on artistic bronze and copper artificial patinas

    NASA Astrophysics Data System (ADS)

    Balta, I. Z.; Pederzoli, S.; Iacob, E.; Bersani, M.

    2009-04-01

    To prevent the natural processes of decay and to develop and improve the treatments of conservation and restoration of artistic bronzes meaning statues and sculptures, it is important understanding the patination processes and the knowledge of artificially corroded surfaces. Chemical and physical characterization of artificial patinas obtained on artistic bronzes and coppers by using the 19th century Western traditional patination techniques and recipes by means of SEM-EDS, light microscopy and ATR/FT-IR has been done in previous studies [I.Z. Balta, L. Robbiola, Characterization of artificial black patinas on artistic cast bronze and pure copper by using SEM-EDS and light microscopy, in: Proceedings of the 13th European Microscopy Congress, 22-27 August 2004, Antwerp, Belgium, EMC 2004 CD-Rom Conference Preprints; I.Z. Balta, L. Robbiola, Traditional artificial artistic bronze and copper patinas—an investigation by SEM-EDS and ATR/FT-IR, in: Proceedings of the 8th International Conference on Non Destructive Investigations and Microanalysis for the Diagnostics and Conservation of the Cultural and Environmental Heritage, 15-19 May 2005, Lecce, Italy, ART'05 CD-Rom Conference Preprints]. Differences in morphology (structure, thickness, porosity, adherence, compactity, uniformity, homogeneity) and also in composition, on both artistic cast bronze and pure copper patinas, were clearly evidenced. Further in-depth investigation is required to be carried out in order to better understand the patinas mechanisms of formation and the layers kinetics of growth. The elemental and chemical analysis, either on a surface monolayer or in a depth profile, by using the Secondary Ion Mass Spectrometry (SIMS) and X-ray Photoelectron Spectroscopy (XPS) techniques, can provide this kind of information, unique at trace-level sensitivity. SIMS has proved to be a suitable analytical technique for analyzing small amounts of material with high atomic sensitivity (ppm or even ppb) and high

  20. Influence of various surface pretreatments on adherence of sputtered molybdenum disulfide to silver, gold, copper, and bronze

    NASA Technical Reports Server (NTRS)

    Spalvins, T.

    1973-01-01

    Solid film lubricants of radio frequency sputtered molybdenum disulfide (MoS2) were applied to silver, gold, copper, and bronze surfaces that had various pretreatments (mechanical polishing, sputter etching, oxidation, and sulfurization). Optical and electron transmission micrographs and electron diffraction patterns were used to interpret the film formation characteristics and to evaluate the sputtering conditions in regard to the film and substrate compatibility. Sputtered MoS2 films flaked and peeled on silver, copper, and bronze surfaces except when the surfaces had been specially oxidized. The flaking and peeling was a result of sulfide compound formation and the corresponding grain growth of the sulfide film. Sputtered MoS2 films showed no peeling and flaking on gold surfaces regardless of surface pretreatment.

  1. The analysis of bronze alloys from the equestrian statue of Marco Aurelio by means of a thin sample XRF technique

    NASA Astrophysics Data System (ADS)

    Ferretti, M.; Cesareo, R.; Marabelli, M.; Guida, G.

    1989-02-01

    The choice of the methods that can be employed in the elemental characterization of archaeological alloys strongly depends on the type, state of conservation and dimensions of the object. The present article describes the analytical approach used for the bronze equestrian statue of Marco Aurelio, for which "in loco" nondestructive analyses could not be performed. The technique is based on the XRF analysis of samples that were previously cored from the statue in small quantities (200 mg), dissolved and deposited on a support in the form of a thin layer. The article also shows some of the results concerned with the analysis of approximately 100 samples; such results were found to be in good agreement with the typical compositions of ancient bronzes.

  2. Short-Term Effect of Nutrient Availability and Rainfall Distribution on Biomass Production and Leaf Nutrient Content of Savanna Tree Species

    PubMed Central

    Barbosa, Eduardo R. M.; Tomlinson, Kyle W.; Carvalheiro, Luísa G.; Kirkman, Kevin; de Bie, Steven; Prins, Herbert H. T.; van Langevelde, Frank

    2014-01-01

    Changes in land use may lead to increased soil nutrient levels in many ecosystems (e.g. due to intensification of agricultural fertilizer use). Plant species differ widely in their response to differences in soil nutrients, and for savannas it is uncertain how this nutrient enrichment will affect plant community dynamics. We set up a large controlled short-term experiment in a semi-arid savanna to test how water supply (even water supply vs. natural rainfall) and nutrient availability (no fertilisation vs. fertilisation) affects seedlings’ above-ground biomass production and leaf-nutrient concentrations (N, P and K) of broad-leafed and fine-leafed tree species. Contrary to expectations, neither changes in water supply nor changes in soil nutrient level affected biomass production of the studied species. By contrast, leaf-nutrient concentration did change significantly. Under regular water supply, soil nutrient addition increased the leaf phosphorus concentration of both fine-leafed and broad-leafed species. However, under uneven water supply, leaf nitrogen and phosphorus concentration declined with soil nutrient supply, this effect being more accentuated in broad-leafed species. Leaf potassium concentration of broad-leafed species was lower when growing under constant water supply, especially when no NPK fertilizer was applied. We found that changes in environmental factors can affect leaf quality, indicating a potential interactive effect between land-use changes and environmental changes on savanna vegetation: under more uneven rainfall patterns within the growing season, leaf quality of tree seedlings for a number of species can change as a response to changes in nutrient levels, even if overall plant biomass does not change. Such changes might affect herbivore pressure on trees and thus savanna plant community dynamics. Although longer term experiments would be essential to test such potential effects of eutrophication via changes in leaf nutrient

  3. Short-term effect of nutrient availability and rainfall distribution on biomass production and leaf nutrient content of savanna tree species.

    PubMed

    Barbosa, Eduardo R M; Tomlinson, Kyle W; Carvalheiro, Luísa G; Kirkman, Kevin; de Bie, Steven; Prins, Herbert H T; van Langevelde, Frank

    2014-01-01

    Changes in land use may lead to increased soil nutrient levels in many ecosystems (e.g. due to intensification of agricultural fertilizer use). Plant species differ widely in their response to differences in soil nutrients, and for savannas it is uncertain how this nutrient enrichment will affect plant community dynamics. We set up a large controlled short-term experiment in a semi-arid savanna to test how water supply (even water supply vs. natural rainfall) and nutrient availability (no fertilisation vs. fertilisation) affects seedlings' above-ground biomass production and leaf-nutrient concentrations (N, P and K) of broad-leafed and fine-leafed tree species. Contrary to expectations, neither changes in water supply nor changes in soil nutrient level affected biomass production of the studied species. By contrast, leaf-nutrient concentration did change significantly. Under regular water supply, soil nutrient addition increased the leaf phosphorus concentration of both fine-leafed and broad-leafed species. However, under uneven water supply, leaf nitrogen and phosphorus concentration declined with soil nutrient supply, this effect being more accentuated in broad-leafed species. Leaf potassium concentration of broad-leafed species was lower when growing under constant water supply, especially when no NPK fertilizer was applied. We found that changes in environmental factors can affect leaf quality, indicating a potential interactive effect between land-use changes and environmental changes on savanna vegetation: under more uneven rainfall patterns within the growing season, leaf quality of tree seedlings for a number of species can change as a response to changes in nutrient levels, even if overall plant biomass does not change. Such changes might affect herbivore pressure on trees and thus savanna plant community dynamics. Although longer term experiments would be essential to test such potential effects of eutrophication via changes in leaf nutrient concentration

  4. [Physiological and growth responses of Sabina vulgaris to disturbance of leaf removal].

    PubMed

    He, W

    2001-04-01

    To examine the physiological and growth responses to Sabina vulgaris to natural disturbance, a field experiment to simulate the grazing and pest disturbance was conducted in Maowusu sandy land through artificially removing leaves. The disturbance of leaf removal could modify the species' diurnal physiological dynamics through changing the timing of extreme values, and moreover, change the average daily values of physiological indexes significantly. Leaf removal could affect the growth traits, but not biomass allocation significantly. The consequences of the disturbance were confined by its means and intensity, and there existed significant differences in sensitivity of different physiological and growth characteristics e.g., net photosynthesis rate and transpiration rate to leaf removal. The disturbance of leaf removal, especially that of old leaf removal, had compensation effects. Therefore, moderately removing the leaves on the shoots with less than 2 years old could enhance the growth and the biomass accumulation of current-year shoots. PMID:11757356

  5. Alloy characterization of a 7th Century BC archeological bronze vase - Overcoming patina constraints using Monte Carlo simulations

    NASA Astrophysics Data System (ADS)

    Manso, M.; Schiavon, N.; Queralt, I.; Arruda, A. M.; Sampaio, J. M.; Brunetti, A.

    2015-05-01

    In this work we evaluate the composition of a bronze alloy using X-ray fluorescence spectrometry (XRF) and Monte Carlo (MC) simulations. For this purpose, a 7th Century BC archeological vase from the SW Iberian Peninsula, displaying a well formed corrosion patina was analyzed by means of a portable X-ray fluorescence spectrometer. Realistic MC simulations of the experimental setup were performed with the XRMC code package which is based on an intensive use of variance-reduction techniques and uses XRAYLIB a constantly updated X-ray library of atomic data. A single layer model was applied for simulating XRF of polished/pristine bronze whereas a two-or-three-layer model was developed for bronze covered respectively by a corrosion patina alone or coupled with a superficial soil derived crust. These simulations took into account corrosion (cerussite (PbCO3), cuprite (Cu2O), malachite (Cu2CO3(OH)2), litharge (PbO)) and soil derived products (goethite (FeO(OH)) and quartz (SiO2)) identified by means of X-ray diffraction and Raman micro analytical techniques. Results confirm previous research indicating that the XRF/Monte Carlo protocol is well suited when a two-layered model is considered, whereas in areas where the patina + soil derived products' crust is too thick, X-rays from the alloy substrate are not able to exit the sample. Quantitative results based on MC simulations indicate that the vase is made of a lead-bronze alloy: Mn (0.2%), Fe (1.0%), Cu (81.8%), As (0.5%), Ag (0.6%), Sn (8.0%) and Pb (8.0%).

  6. Behavior of Leaf Meristems and Their Modification

    PubMed Central

    Ichihashi, Yasunori; Tsukaya, Hirokazu

    2015-01-01

    A major source of diversity in flowering plant form is the extensive variability of leaf shape and size. Leaf formation is initiated by recruitment of a handful of cells flanking the shoot apical meristem (SAM) to develop into a complex three-dimensional structure. Leaf organogenesis depends on activities of several distinct meristems that are established and spatiotemporally differentiated after the initiation of leaf primordia. Here, we review recent findings in the gene regulatory networks that orchestrate leaf meristem activities in a model plant Arabidopsis thaliana. We then discuss recent key studies investigating the natural variation in leaf morphology to understand how the gene regulatory networks modulate leaf meristems to yield a substantial diversity of leaf forms during the course of evolution. PMID:26648955

  7. Paleopathological Description and Diagnosis of Metastatic Carcinoma in an Early Bronze Age (4588+34 Cal. BP) Forager from the Cis-Baikal Region of Eastern Siberia

    PubMed Central

    Lieverse, Angela R.; Temple, Daniel H.; Bazaliiskii, Vladimir I.

    2014-01-01

    Extensive osteolytic and osteoblastic lesions were observed on the skeletal remains of an adult male excavated from an Early Bronze Age cemetery dated to 4556+32 years BP, located in the Cis-Baikal region of Siberia (Russian Federation). Lytic lesions ranged in size from several mm to over 60 mm in diameter and had irregular, moth-eaten borders. Many of these lesions destroyed trabecular bone, though a hollowed shell of cortical bone often remained observable. Radiographic analysis revealed numerous lytic lesions within trabecular bone that had not yet affected the cortex. Blastic lesions were identified as spiculated lines, bands, or nodules of mostly immature (woven) bone formed at irregular intervals. Anatomical elements with the greatest involvement included those of the axial skeleton (skull, vertebrae, sacrum, ribs, and sternum) as well as proximal appendicular elements (ossa coxae, proximal femora, clavicles, scapulae, and proximal humeri). Osteocoalescence of destructive foci was observed on the ilium and frontal bone, with the largest lesion found on the right ilium. Differential diagnoses include metastatic carcinoma, mycotic infections, tuberculosis, Langerhan's cell histiocytosis, and multiple myeloma. Based on lesion appearance and distribution, age and sex of the individual, as well as pathogen endemism, the most likely diagnostic option for this set of lesions is metastatic carcinoma. The age and sex of this individual and appearance of the lesions may reflect carcinoma of the lung or, possibly, prostate. This represents one of the earliest cases of metastatic carcinoma worldwide and the oldest case documented thus far from Northeast Asia. PMID:25470373

  8. Expression and RNA splicing of the maize glutathione S-transferase Bronze2 gene is regulated by cadmium and other stresses.

    PubMed Central

    Marrs, K A; Walbot, V

    1997-01-01

    The Bronze2 (Bz2) gene in maize (Zea mays) encodes a glutathione S-transferase that performs the last genetically defined step in anthocyanin biosynthesis--tagging anthocyanin precursors with glutathione, allowing for recognition and entry of anthocyanins into the vacuole. Here we show that Bz2 gene expression is highly induced by heavy metals such as cadmium. Treatment of maize seedlings with cadmium results in a 20-fold increase in Bz2 message accumulation and a 50-fold increase in the presence of the unspliced, intron-containing transcript. The increase in message levels during cadmium stress appears to result, at least in part, from activation of an alternative mRNA start site approximately 200 nucleotides upstream of the normal start site; this site is not used in unstressed or heat-stressed tissues. The effect of cadmium on the RNA splicing of Bz2 seems to be specific: splicing of other intron-containing maize genes, including a maize actin gene under the control of the cadmium-inducible Bz2 promoter, is unaffected by cadmium stress. Conversely, Bz2 intron splicing is not affected by other stress conditions that induce Bz2 gene expression, such as abscisic acid, auxin, or cold stress. Surprisingly, the increase in Bz2 mRNA during cadmium stress does not result in an increase in Bz2 glutathione S-transferase activity. We propose that an alternative protein may be encoded by Bz2 that has a role during responses to heavy metals. PMID:9008391

  9. Paleopathological description and diagnosis of metastatic carcinoma in an Early Bronze Age (4588+34 Cal. BP) forager from the Cis-Baikal region of Eastern Siberia.

    PubMed

    Lieverse, Angela R; Temple, Daniel H; Bazaliiskii, Vladimir I

    2014-01-01

    Extensive osteolytic and osteoblastic lesions were observed on the skeletal remains of an adult male excavated from an Early Bronze Age cemetery dated to 4556+32 years BP, located in the Cis-Baikal region of Siberia (Russian Federation). Lytic lesions ranged in size from several mm to over 60 mm in diameter and had irregular, moth-eaten borders. Many of these lesions destroyed trabecular bone, though a hollowed shell of cortical bone often remained observable. Radiographic analysis revealed numerous lytic lesions within trabecular bone that had not yet affected the cortex. Blastic lesions were identified as spiculated lines, bands, or nodules of mostly immature (woven) bone formed at irregular intervals. Anatomical elements with the greatest involvement included those of the axial skeleton (skull, vertebrae, sacrum, ribs, and sternum) as well as proximal appendicular elements (ossa coxae, proximal femora, clavicles, scapulae, and proximal humeri). Osteocoalescence of destructive foci was observed on the ilium and frontal bone, with the largest lesion found on the right ilium. Differential diagnoses include metastatic carcinoma, mycotic infections, tuberculosis, Langerhan's cell histiocytosis, and multiple myeloma. Based on lesion appearance and distribution, age and sex of the individual, as well as pathogen endemism, the most likely diagnostic option for this set of lesions is metastatic carcinoma. The age and sex of this individual and appearance of the lesions may reflect carcinoma of the lung or, possibly, prostate. This represents one of the earliest cases of metastatic carcinoma worldwide and the oldest case documented thus far from Northeast Asia. PMID:25470373

  10. Isotopic Evidence For The Primary Production, Provenance And Trade Of Late Bronze Age Glass In The Mediterranean.

    NASA Astrophysics Data System (ADS)

    Henderson, J.; Evans, J.; Nikita, K.

    The earliest known man made glass comes from Mesopotamia and dates to the 23rd century BC. By the 16th century BC the first glass vessels appear in Mesopotamia, but the earliest evidence for the fusion of glass from raw materials has been found at the 13th century BC Egyptian site of Qantir. Chemical analyses of this elite Late Bronze Age material have produced compositional distinctions between glasses found in Mesopotamia and Egypt. It is however debatable whether trace element concentrations provide a (geological) provenance for the glasses. By using neodymium and strontium isotopes to fingerprint well-dated chemically analysed 15th to 11th century BC glass samples, we show that independent primary production probably occurred in both Egypt and Mesopotamia in the 14th century BC, and that both of these areas exported glass to Greece. We also discuss the technological implications for glass manufacture and colouring that these new data provide. The results add significant new scientific evidence for glass trade between Late Bronze Age palatial societies. Moreover, it is the first time that this methodology has been used to investigate Bronze Age glass.

  11. Multipeak self-biased magnetoelectric coupling characteristics in four-phase Metglas/Terfenol-D/Be-bronze/PMN-PT structure

    NASA Astrophysics Data System (ADS)

    Huang, Dongyan; Lu, Caijiang; Bing, Han

    2015-04-01

    This letter develops a self-biased magnetoelectric (ME) structure Metglas/Terfenol-D/Be-bronze/PMN-PT (MTBP) consisting of a magnetization-graded Metglas/Terfenol-D layer, a elastic Be-bronze plate, and a piezoelectric 0.67Pb(Mg1/3Nb2/3)O3-0.33PbTiO3 (PMN-PT) plate. By using the magnetization-graded Metglas/Terfenol-D layer and the elastic Be-bronze plate, multi-peak self-biased ME responses are obtained in MTBP structure. The experimental results show that the MTBP structure with two layers of Metglas foil has maximum zero-biased ME voltage coefficient (MEVC). As frequency increases from 0.5 to 90 kHz, eleven large peaks of MEVC with magnitudes of 0.75-33 V/(cm Oe) are observed at zero-biased magnetic field. The results demonstrate that the proposed multi-peak self-biased ME structure may be useful for multifunctional devices such as multi-frequency energy harvesters or low-frequency ac magnetic field sensors.

  12. A New Chronology for the Bronze Age of Northeastern Thailand and Its Implications for Southeast Asian Prehistory

    PubMed Central

    Higham, Charles F. W.

    2015-01-01

    There are two models for the origins and timing of the Bronze Age in Southeast Asia. The first centres on the sites of Ban Chiang and Non Nok Tha in Northeast Thailand. It places the first evidence for bronze technology in about 2000 B.C., and identifies the origin by means of direct contact with specialists of the Seima Turbino metallurgical tradition of Central Eurasia. The second is based on the site of Ban Non Wat, 280 km southwest of Ban Chiang, where extensive radiocarbon dating places the transition into the Bronze Age in the 11th century B.C. with likely origins in a southward expansion of technological expertise rooted in the early states of the Yellow and Yangtze valleys, China. We have redated Ban Chiang and Non Nok Tha, as well as the sites of Ban Na Di and Ban Lum Khao, and here present 105 radiocarbon determinations that strongly support the latter model. The statistical analysis of the results using a Bayesian approach allows us to examine the data at a regional level, elucidate the timing of arrival of copper base technology in Southeast Asia and consider its social impact. PMID:26384011

  13. A New Chronology for the Bronze Age of Northeastern Thailand and Its Implications for Southeast Asian Prehistory.

    PubMed

    Higham, Charles F W; Douka, Katerina; Higham, Thomas F G

    2015-01-01

    There are two models for the origins and timing of the Bronze Age in Southeast Asia. The first centres on the sites of Ban Chiang and Non Nok Tha in Northeast Thailand. It places the first evidence for bronze technology in about 2000 B.C., and identifies the origin by means of direct contact with specialists of the Seima Turbino metallurgical tradition of Central Eurasia. The second is based on the site of Ban Non Wat, 280 km southwest of Ban Chiang, where extensive radiocarbon dating places the transition into the Bronze Age in the 11th century B.C. with likely origins in a southward expansion of technological expertise rooted in the early states of the Yellow and Yangtze valleys, China. We have redated Ban Chiang and Non Nok Tha, as well as the sites of Ban Na Di and Ban Lum Khao, and here present 105 radiocarbon determinations that strongly support the latter model. The statistical analysis of the results using a Bayesian approach allows us to examine the data at a regional level, elucidate the timing of arrival of copper base technology in Southeast Asia and consider its social impact. PMID:26384011

  14. Bronze Age pottery from the Aeolian Islands: definition of Temper Compositional Reference Units by an integrated mineralogical and microchemical approach

    NASA Astrophysics Data System (ADS)

    Brunelli, D.; Levi, S. T.; Fragnoli, P.; Renzulli, A.; Santi, P.; Paganelli, E.; Martinelli, M. C.

    2013-12-01

    An integrated microchemical-petrographic approach is here proposed to discriminate the provenance of archaeological pottery artefacts from distinct production centres. Our study focuses on a statistically significant sampling ( n=186) of volcanic temper-bearing potteries representative of the manufacturing and dispersion among the islands of the Aeolian Archipelago during the Bronze Age. The widespread establishment of new settlements and the abundant recovery of Aeolian-made ceramic in southern Italy attest for the increased vitality of the Archipelago during the Capo Graziano culture (Early Bronze Age-Middle Bronze Age 2; 2300-1430 BC). Potteries from three of the main known ancient communities (Lipari, Filicudi and Stromboli) have been studied integrating old collections and newly excavated material. Volcanic tempers have been first investigated through multivariate analyses of relative abundances of mineral and rock clasts along with petrographic characters. In addition, we performed in-situ mineral chemistry microanalyses by Electron Microprobe and Laser Ablation—Inductively Coupled Plasma Mass Spectrometry to assess major and trace element composition of the most common mineral phases. Four Temper Compositional Reference Units have been recognised based on compositional trends. Two units (AI and AX) are unequivocally distinct by their peculiar trace element enrichment and petrographic composition; they mostly contain samples from the sites of Lipari and Stromboli, respectively. Units AIV and AVIII, restricted to the sites of Filicudi and Stromboli, show distinct petrographic characters but overlapped geochemical fingerprints.

  15. Relationships between sugarcane leaf hyperspectral reflectance, leaf nitrogen content, and yield components

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf spectral reflectance has been used to estimate crop leaf chemical composition and other physiological characters. Leaf reflectance of sugarcane (Saccharum spp.) may be of use in evaluating genotypes. The objectives of this study were: (1) to identify sugarcane genotypic variation in leaf hypers...

  16. Analysis of Circadian Leaf Movements.

    PubMed

    Müller, Niels A; Jiménez-Gómez, José M

    2016-01-01

    The circadian clock is a molecular timekeeper that controls a wide variety of biological processes. In plants, clock outputs range from the molecular level, with rhythmic gene expression and metabolite content, to physiological processes such as stomatal conductance or leaf movements. Any of these outputs can be used as markers to monitor the state of the circadian clock. In the model plant Arabidopsis thaliana, much of the current knowledge about the clock has been gained from time course experiments profiling expression of endogenous genes or reporter constructs regulated by the circadian clock. Since these methods require labor-intensive sample preparation or transformation, monitoring leaf movements is an interesting alternative, especially in non-model species and for natural variation studies. Technological improvements both in digital photography and image analysis allow cheap and easy monitoring of circadian leaf movements. In this chapter we present a protocol that uses an autonomous point and shoot camera and free software to monitor circadian leaf movements in tomato. PMID:26867616

  17. Exobasidium leaf and fruit spot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During the past five or so years blueberry growers in south Mississippi have discovered the disease Exobasidium leaf and fruit spot on some of their blueberry plants. In the past this disease was considered to be of minor importance occurring infrequently on isolated farms. But in recent years it ...

  18. Analysis and modelling of effects of leaf rust and Septoria tritici blotch on wheat growth.

    PubMed

    Robert, Corinne; Bancal, Marie-Odile; Nicolas, Pierre; Lannou, Christian; Ney, Bertrand

    2004-05-01

    A model to predict Septoria tritici blotch (STB) and leaf rust effects on wheat growth was constructed and evaluated in two steps. At the leaf scale, Bastiaans' approach that predicts the relative photosynthesis of a wheat leaf infected with a single disease, was extended to the case of two diseases, one biotrophic and one necrotrophic by considering the leaf rust-STB complex. A glasshouse experiment with flag leaves inoculated either singly with one disease or with two diseases combined was performed to check the leaf damage model. No interaction of the two diseases on photosynthesis loss was observed when they occurred simultaneously on the same leaf. In a second step, the single-leaf model was extended to the canopy scale to model the effects of the leaf rust-STB complex on the growth of a wheat crop. The model predicts the effects of disease on the growth of an affected crop relative to the growth of a healthy crop. The canopy model accounted for different contributions to photosynthetic activity of leaf layers, derived from their position in the canopy and their natural leaf senescence. Treatments differing in nitrogen fertilization, microclimatic conditions, and wheat cultivars were implemented in a field experiment to evaluate the model. The model accurately estimated the effect of disease on crop growth for each cultivar, with differences from experimental values lower than 10%, which suggests that this model is well suited to aid an understanding of disease effects on plant growth. A reduction in green leaf area was the main effect of disease in these field experiments and STB accounted for more than 70% of the reduction in plant growth. Simulations suggested that the production of rust spores may result in a loss of biomass from diseased crops and that stem photosynthesis may need to be considered in modelling diseased crop growth. PMID:15073221

  19. 7 CFR 29.6023 - Leaf structure.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.6023 Section 29.6023 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing... INSPECTION Standards Definitions § 29.6023 Leaf structure. The cell development of a leaf as indicated by...

  20. 7 CFR 29.3035 - Leaf structure.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Leaf structure. The cell development of a leaf as indicated by its porosity or solidity. (See Elements... 7 Agriculture 2 2011-01-01 2011-01-01 false Leaf structure. 29.3035 Section 29.3035 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  1. 7 CFR 29.6023 - Leaf structure.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... INSPECTION Standards Definitions § 29.6023 Leaf structure. The cell development of a leaf as indicated by its... 7 Agriculture 2 2012-01-01 2012-01-01 false Leaf structure. 29.6023 Section 29.6023 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  2. 7 CFR 29.1030 - Leaf structure.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Type 92) § 29.1030 Leaf structure. The cell development of a leaf as indicated by its porosity. (See... 7 Agriculture 2 2011-01-01 2011-01-01 false Leaf structure. 29.1030 Section 29.1030 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  3. 7 CFR 29.1030 - Leaf structure.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Type 92) § 29.1030 Leaf structure. The cell development of a leaf as indicated by its porosity. (See... 7 Agriculture 2 2013-01-01 2013-01-01 false Leaf structure. 29.1030 Section 29.1030 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  4. 7 CFR 29.6023 - Leaf structure.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... INSPECTION Standards Definitions § 29.6023 Leaf structure. The cell development of a leaf as indicated by its... 7 Agriculture 2 2011-01-01 2011-01-01 false Leaf structure. 29.6023 Section 29.6023 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  5. 7 CFR 29.3527 - Leaf structure.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Type 95) § 29.3527 Leaf structure. The cell development of a leaf as indicated by its porosity. (See... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.3527 Section 29.3527 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  6. 7 CFR 29.3035 - Leaf structure.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Leaf structure. The cell development of a leaf as indicated by its porosity or solidity. (See Elements... 7 Agriculture 2 2012-01-01 2012-01-01 false Leaf structure. 29.3035 Section 29.3035 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  7. 7 CFR 29.1030 - Leaf structure.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Type 92) § 29.1030 Leaf structure. The cell development of a leaf as indicated by its porosity. (See... 7 Agriculture 2 2012-01-01 2012-01-01 false Leaf structure. 29.1030 Section 29.1030 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  8. 7 CFR 29.6023 - Leaf structure.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... INSPECTION Standards Definitions § 29.6023 Leaf structure. The cell development of a leaf as indicated by its... 7 Agriculture 2 2013-01-01 2013-01-01 false Leaf structure. 29.6023 Section 29.6023 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  9. 7 CFR 29.3527 - Leaf structure.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Type 95) § 29.3527 Leaf structure. The cell development of a leaf as indicated by its porosity. (See... 7 Agriculture 2 2013-01-01 2013-01-01 false Leaf structure. 29.3527 Section 29.3527 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  10. 7 CFR 29.3035 - Leaf structure.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Leaf structure. The cell development of a leaf as indicated by its porosity or solidity. (See Elements... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf structure. 29.3035 Section 29.3035 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  11. 7 CFR 29.3527 - Leaf structure.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Type 95) § 29.3527 Leaf structure. The cell development of a leaf as indicated by its porosity. (See... 7 Agriculture 2 2012-01-01 2012-01-01 false Leaf structure. 29.3527 Section 29.3527 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  12. 7 CFR 29.3527 - Leaf structure.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Type 95) § 29.3527 Leaf structure. The cell development of a leaf as indicated by its porosity. (See... 7 Agriculture 2 2011-01-01 2011-01-01 false Leaf structure. 29.3527 Section 29.3527 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  13. 7 CFR 29.3035 - Leaf structure.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Leaf structure. The cell development of a leaf as indicated by its porosity or solidity. (See Elements... 7 Agriculture 2 2013-01-01 2013-01-01 false Leaf structure. 29.3035 Section 29.3035 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections,...

  14. Tree branch angle: maximizing effective leaf area.

    PubMed

    Honda, H; Fisher, J B

    1978-02-24

    In a computer simulation of branching pattern and leaf cluster in Terminalia catappa, right and left branch angles were varied, and the effective leaf surface areas were calculated. Theoretical branch angles that result in maximum effective leaf area are close to the values observed in nature. PMID:17757590

  15. 7 CFR 29.3034 - Leaf scrap.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Leaf scrap. A by-product of unstemmed tobacco. Leaf scrap results from handling unstemmed tobacco and... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.3034 Section 29.3034 Agriculture... Practices), DEPARTMENT OF AGRICULTURE COMMODITY STANDARDS AND STANDARD CONTAINER REGULATIONS...

  16. 7 CFR 29.3526 - Leaf scrap.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Type 95) § 29.3526 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap results from handling unstemmed tobacco and consists of loose and tangled whole or broken leaves. ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.3526 Section 29.3526...

  17. 7 CFR 29.2529 - Leaf scrap.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...-Cured Tobacco (u.s. Types 22, 23, and Foreign Type 96) § 29.2529 Leaf scrap. A byproduct of unstemmed tobacco. Leaf scrap results from handling unstemmed tobacco and consists of loose and tangled whole or... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.2529 Section 29.2529...

  18. 7 CFR 29.6022 - Leaf scrap.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... INSPECTION Standards Definitions § 29.6022 Leaf scrap. A byproduct of unstemmed tobacco Leaf scrap results from handling unstemmed tobacco and consists of loose and tangled whole or broken leaves. ... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.6022 Section 29.6022...

  19. 7 CFR 29.2277 - Leaf scrap.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... INSPECTION Standards Official Standard Grades for Virginia Fire-Cured Tobacco (u.s. Type 21) § 29.2277 Leaf scrap. A byproduct of unstemmed tobacco. Leaf scrap results from handling unstemmed tobacco and consists... 7 Agriculture 2 2010-01-01 2010-01-01 false Leaf scrap. 29.2277 Section 29.2277...

  20. The triple isotopic composition of oxygen in leaf water

    NASA Astrophysics Data System (ADS)

    Landais, A.; Barkan, E.; Yakir, D.; Luz, B.

    2006-08-01

    The isotopic composition of atmospheric O 2 depends on the rates of oxygen cycling in photosynthesis, respiration, photochemical reactions in the stratosphere and on δ17O and δ18O of ocean and leaf water. While most of the factors affecting δ17O and δ18O of air O 2 have been studied extensively in recent years, δ17O of leaf water—the substrate for all terrestrial photosynthesis—remained unknown. In order to understand the isotopic composition of atmospheric O 2 at present and in fossil air in ice cores, we studied leaf water in field experiments in Israel and in a European survey. We measured the difference in δ17O and δ18O between stem and leaf water, which is the result of isotope enrichment during transpiration. We calculated the slopes of the lines linking the isotopic compositions of stem and leaf water. The obtained slopes in ln( δ17O + 1) vs. ln( δ18O + 1) plots are characterized by very high precision (˜0.001) despite of relatively large differences between duplicates in both δ17O and δ18O (0.02-0.05‰). This is so because the errors in δ18O and δ17O are mass-dependent. The slope of the leaf transpiration process varied between 0.5111 ± 0.0013 and 0.5204 ± 0.0005, which is considerably smaller than the slope linking liquid water and vapor at equilibrium (0.529). We further found that the slope of the transpiration process decreases with atmospheric relative humidity ( h) as 0.522-0.008 × h, for h in the range 0.3-1. This slope is neither influenced by the plant species, nor by the environmental conditions where plants grow nor does it show strong variations along long leaves.

  1. Comparison of half and full-leaf shape feature extraction for leaf classification

    NASA Astrophysics Data System (ADS)

    Sainin, Mohd Shamrie; Ahmad, Faudziah; Alfred, Rayner

    2016-08-01

    Shape is the main information for leaf feature that most of the current literatures in leaf identification utilize the whole leaf for feature extraction and to be used in the leaf identification process. In this paper, study of half-leaf features extraction for leaf identification is carried out and the results are compared with the results obtained from the leaf identification based on a full-leaf features extraction. Identification and classification is based on shape features that are represented as cosines and sinus angles. Six single classifiers obtained from WEKA and seven ensemble methods are used to compare their performance accuracies over this data. The classifiers were trained using 65 leaves in order to classify 5 different species of preliminary collection of Malaysian medicinal plants. The result shows that half-leaf features extraction can be used for leaf identification without decreasing the predictive accuracy.

  2. First Report of Bacterial Leaf Blight on Broccoli and Cabbage Caused by Pseudomonas syringae pv. alisalensis in South Carolina

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In May 2009, leaf spot and leaf blight symptoms were observed on broccoli (B. oleracea var. italica) and cabbage (Brassica oleracea var. capitata) on several farms in Lexington County, the major brassica-growing region of South Carolina. Affected areas ranged from scattered disease foci within fiel...

  3. Modeling development and quantitative trait mapping reveal independent genetic modules for leaf size and shape.

    PubMed

    Baker, Robert L; Leong, Wen Fung; Brock, Marcus T; Markelz, R J Cody; Covington, Michael F; Devisetty, Upendra K; Edwards, Christine E; Maloof, Julin; Welch, Stephen; Weinig, Cynthia

    2015-10-01

    Improved predictions of fitness and yield may be obtained by characterizing the genetic controls and environmental dependencies of organismal ontogeny. Elucidating the shape of growth curves may reveal novel genetic controls that single-time-point (STP) analyses do not because, in theory, infinite numbers of growth curves can result in the same final measurement. We measured leaf lengths and widths in Brassica rapa recombinant inbred lines (RILs) throughout ontogeny. We modeled leaf growth and allometry as function valued traits (FVT), and examined genetic correlations between these traits and aspects of phenology, physiology, circadian rhythms and fitness. We used RNA-seq to construct a SNP linkage map and mapped trait quantitative trait loci (QTL). We found genetic trade-offs between leaf size and growth rate FVT and uncovered differences in genotypic and QTL correlations involving FVT vs STPs. We identified leaf shape (allometry) as a genetic module independent of length and width and identified selection on FVT parameters of development. Leaf shape is associated with venation features that affect desiccation resistance. The genetic independence of leaf shape from other leaf traits may therefore enable crop optimization in leaf shape without negative effects on traits such as size, growth rate, duration or gas exchange. PMID:26083847

  4. Root-to-shoot signalling when soil moisture is heterogeneous: increasing the proportion of root biomass in drying soil inhibits leaf growth and increases leaf abscisic acid concentration.

    PubMed

    Martin-Vertedor, Ana Isabel; Dodd, Ian C

    2011-07-01

    To determine whether root-to-shoot signalling of soil moisture heterogeneity depended on root distribution, wild-type (WT) and abscisic acid (ABA)-deficient (Az34) barley (Hordeum vulgare) plants were grown in split pots into which different numbers of seminal roots were inserted. After establishment, all plants received the same irrigation volumes, with one pot watered (w) and the other allowed to dry the soil (d), imposing three treatments (1 d: 3 w, 2 d: 2 w, 3 d: 1 w) that differed in the number of seminal roots exposed to drying soil. Root distribution did not affect leaf water relations and had no sustained effect on plant evapotranspiration (ET). In both genotypes, leaf elongation was less and leaf ABA concentrations were higher in plants with more roots in drying soil, with leaf ABA concentrations and water potentials 30% and 0.2 MPa higher, respectively, in WT plants. Whole-pot soil drying increased xylem ABA concentrations, but maximum values obtained when leaf growth had virtually ceased (100 nm in Az34, 330 nm in WT) had minimal effects (<40% leaf growth inhibition) when xylem supplied to detached shoots. Although ABA may not regulate leaf growth in vivo, genetic variation in foliar ABA concentration in the field may indicate different root distributions between upper (drier) and lower (wetter) soil layers. PMID:21410712

  5. 7 CFR 29.3648 - Thin Leaf (C Group).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... specifications, and tolerances C1L Choice Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth... injury tolerance. C2L Fine Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth, oily... tolerance. C4L Fair Quality Light-brown Thin Leaf. Mature, thin, close leaf structure, rough, lean in...

  6. 7 CFR 29.3648 - Thin Leaf (C Group).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... specifications, and tolerances C1L Choice Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth... injury tolerance. C2L Fine Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth, oily... tolerance. C4L Fair Quality Light-brown Thin Leaf. Mature, thin, close leaf structure, rough, lean in...

  7. 7 CFR 29.3648 - Thin Leaf (C Group).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... specifications, and tolerances C1L Choice Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth... injury tolerance. C2L Fine Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth, oily... tolerance. C4L Fair Quality Light-brown Thin Leaf. Mature, thin, close leaf structure, rough, lean in...

  8. 7 CFR 29.3648 - Thin Leaf (C Group).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... specifications, and tolerances C1L Choice Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth... injury tolerance. C2L Fine Quality Light-brown Thin Leaf. Ripe, thin, open leaf structure, smooth, oily... tolerance. C4L Fair Quality Light-brown Thin Leaf. Mature, thin, close leaf structure, rough, lean in...

  9. 7 CFR 29.3648 - Thin Leaf (C Group).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... tolerance. C4L Fair Quality Light-brown Thin Leaf. Mature, thin, close leaf structure, rough, lean in oil... tolerance. C5L Low Quality Light-brown Thin Leaf Underripe, thin, close leaf structure, rough, lean in oil... tolerance. C4F Fair Quality Medium-brown Thin Leaf. Mature, thin, close leaf structure, rough, lean in...

  10. 7 CFR 29.1162 - Leaf (B Group).

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Specifications, and Tolerances B1L—Choice Quality Lemon Leaf Ripe, firm leaf structure, medium body, rich in oil... percent. B2L—Fine Quality Lemon Leaf Ripe, firm leaf structure, medium body, rich in oil, deep color.... B3L—Good Quality Lemon Leaf Ripe, firm leaf structure, medium body, oily, strong color...

  11. 7 CFR 29.1162 - Leaf (B Group).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Specifications, and Tolerances B1L—Choice Quality Lemon Leaf Ripe, firm leaf structure, medium body, rich in oil... percent. B2L—Fine Quality Lemon Leaf Ripe, firm leaf structure, medium body, rich in oil, deep color.... B3L—Good Quality Lemon Leaf Ripe, firm leaf structure, medium body, oily, strong color...

  12. 7 CFR 29.1162 - Leaf (B Group).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Specifications, and Tolerances B1L—Choice Quality Lemon Leaf Ripe, firm leaf structure, medium body, rich in oil... percent. B2L—Fine Quality Lemon Leaf Ripe, firm leaf structure, medium body, rich in oil, deep color.... B3L—Good Quality Lemon Leaf Ripe, firm leaf structure, medium body, oily, strong color...

  13. 7 CFR 29.1162 - Leaf (B Group).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Specifications, and Tolerances B1L—Choice Quality Lemon Leaf Ripe, firm leaf structure, medium body, rich in oil... percent. B2L—Fine Quality Lemon Leaf Ripe, firm leaf structure, medium body, rich in oil, deep color.... B3L—Good Quality Lemon Leaf Ripe, firm leaf structure, medium body, oily, strong color...

  14. 7 CFR 29.1162 - Leaf (B Group).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Specifications, and Tolerances B1L—Choice Quality Lemon Leaf Ripe, firm leaf structure, medium body, rich in oil... percent. B2L—Fine Quality Lemon Leaf Ripe, firm leaf structure, medium body, rich in oil, deep color.... B3L—Good Quality Lemon Leaf Ripe, firm leaf structure, medium body, oily, strong color...

  15. A family of rare earth molybdenum bronzes: Oxides consisting of periodic arrays of interacting magnetic units

    SciTech Connect

    Schneemeyer, L.F.; Siegrist, T.; Besara, T.; Lundberg, M.; Sun, J.; Singh, D.J.

    2015-07-15

    The family of rare earth molybdenum bronzes, reduced ternary molybdates of composition LnMo{sub 16}O{sub 44,} was synthesized and a detailed structural study carried out. Bond valence sum (BVS) calculations clearly show that the molybdenum ions in tetrahedral coordination are hexavalent while the electron count in the primitive unit cell is odd. Yet, measurements show that the phases are semiconductors. The temperature dependence of the magnetic susceptibility of samples containing several different rare earth elements was measured. These measurements verified the presence of a 6.5 K magnetic phase transition not arising from the rare earth constituent, but likely associated with the unique isolated ReO{sub 3}-type Mo{sub 8}O{sub 36} structural subunits in this phase. To better understand the behavior of these materials, electronic structure calculations were performed within density functional theory. Results suggest a magnetic state in which these structural moieties have an internal ferromagnetic arrangement, with small ~1/8 μ{sub B} moments on each Mo. We suggest that the Mo{sub 8}O{sub 36} units behave like pseudoatoms with spin 1/2 derived from a single hole distributed over the eight Mo atoms that are strongly hybridized with the O atoms of the subunit. Interestingly, while the compound is antiferromagnetic, our calculations suggest that a field-stabilized ferromagnetic state, if achievable, will be a narrow band half-metal. - Graphical abstract: LnMo{sub 16}O{sub 44} phases comprise corner sharing tetrahedral and octahedral molybdenum ions. The MoO{sub 6} octahedra form Mo{sub 8}O{sub 36} units that are well separated and act like pseudo-atoms, accommodating 11 electrons each. - Highlights: • Single crystal X-ray diffraction refinements of LnMo{sub 16}O{sub 44} single crystals for Ln=Ce, Pr, Nd, Tb, Dy and Ho. • DFT calculations based on LaMo{sub 16}O{sub 44}. • [Mo{sub 8}O{sub 36}] units behaving as superatoms with a net magnetic moment of 1 µ

  16. Relative sea-level change in the central Cyclades (Greece) since the Early Bronze Age

    NASA Astrophysics Data System (ADS)

    Draganits, E.

    2012-04-01

    The Aegean is a focus of important cultural achievements in Europe since the Neolithic period. The resulting abundance of archaeological remains, many of them below sea-level represent an advantageous area for the study of local relative sea-level change. We have carried out detailed mapping of Despotiko Island (SW of Antiparos) and its surrounding. Despotiko is situated almost exactly in the center of the Cyclades (as defined nowadays), more so than Delos, and therefore is very well suited for sea-level studies of the Cyclades. This beneficial location, combined with a spacious and protected bay, additionally may explain its former importance as stepping-stone in the Aegean Sea. The island is uninhabited at present, but Early Bronze Age settlement sites and graveyards as well as a large Archaic sanctuary proof its former importance. The sanctuary is situated on a gently northeast dipping slope in the northeast part of Despotiko, in range of sight of the Órmos Despotiko. Since 1997 large parts of this important sanctuary have been excavated during several excavation campaigns. Tectonically, Despotiko, Antiparos and Paros, belong to the Attic-Cycladic Crystalline of the Central Hellenides, a stack of metamorphic tectonic nappes, mainly comprising variable types of gneiss, schist, marble and amphibolite, and tectonic slices of unmetamorphosed sediments on top, separated by low-angle normal faults from the metamorphic units below. Submerged archaeological structures at the sea bottom of the Órmos Despotiko, a Classical marble inscription from the sanctuary and partly submerged agriculture trenches at the east coast Despotiko, indicate that the relative sea-level in this area was some 3 m lower during the Early Bronze Age and still more than 1 m lower during Classical time. These values of relative sea-level rise indicate a subsidence component additional to the global sea-level rise in the investigated time period. Neglecting possible vertical tectonic movements and

  17. The Effects of Leaf Roughness, Surface Free Energy and Work of Adhesion on Leaf Water Drop Adhesion

    PubMed Central

    Wang, Huixia; Shi, Hui; Li, Yangyang; Wang, Yanhui

    2014-01-01

    The adhesion of water droplets to leaves is important in controlling rainfall interception, and affects a variety of hydrological processes. Leaf water drop adhesion (hereinafter, adhesion) depends not only on droplet formulation and parameters but also on the physical (leaf roughness) and physico-chemical (surface free energy, its components, and work-of-adhesion) properties of the leaf surface. We selected 60 plant species from Shaanxi Province, NW China, as experimental materials with the goal of gaining insight into leaf physical and physico-chemical properties in relation to the adhesion of water droplets on leaves. Adhesion covered a wide range of area, from 4.09 to 88.87 g/m2 on adaxial surfaces and 0.72 to 93.35 g/m2 on abaxial surfaces. Distinct patterns of adhesion were observed among species, between adaxial and abaxial surfaces, and between leaves with wax films and wax crystals. Adhesion decreased as leaf roughness increased (r =  −0.615, p = 0.000), but there were some outliers, such as Salix psammophila and Populus simonii with low roughness and low adhesion, and the abaxial surface of Hyoscyamus pusillus and the adaxial surface of Vitex negundo with high roughness and high adhesion. Meanwhile, adhesion was positively correlated with surface free energy (r = 0.535, p = 0.000), its dispersive component (r = 0.526, p = 0.000), and work of adhesion for water (r = 0.698, p = 0.000). However, a significant power correlation was observed between adhesion and the polar component of surface free energy (p = 0.000). These results indicated that leaf roughness, surface free energy, its components, and work-of-adhesion for water played important roles in hydrological characteristics, especially work-of-adhesion for water. PMID:25198355

  18. The effects of leaf roughness, surface free energy and work of adhesion on leaf water drop adhesion.

    PubMed

    Wang, Huixia; Shi, Hui; Li, Yangyang; Wang, Yanhui

    2014-01-01

    The adhesion of water droplets to leaves is important in controlling rainfall interception, and affects a variety of hydrological processes. Leaf water drop adhesion (hereinafter, adhesion) depends not only on droplet formulation and parameters but also on the physical (leaf roughness) and physico-chemical (surface free energy, its components, and work-of-adhesion) properties of the leaf surface. We selected 60 plant species from Shaanxi Province, NW China, as experimental materials with the goal of gaining insight into leaf physical and physico-chemical properties in relation to the adhesion of water droplets on leaves. Adhesion covered a wide range of area, from 4.09 to 88.87 g/m(2) on adaxial surfaces and 0.72 to 93.35 g/m(2) on abaxial surfaces. Distinct patterns of adhesion were observed among species, between adaxial and abaxial surfaces, and between leaves with wax films and wax crystals. Adhesion decreased as leaf roughness increased (r =  -0.615, p = 0.000), but there were some outliers, such as Salix psammophila and Populus simonii with low roughness and low adhesion, and the abaxial surface of Hyoscyamus pusillus and the adaxial surface of Vitex negundo with high roughness and high adhesion. Meanwhile, adhesion was positively correlated with surface free energy (r = 0.535, p = 0.000), its dispersive component (r = 0.526, p = 0.000), and work of adhesion for water (r = 0.698, p = 0.000). However, a significant power correlation was observed between adhesion and the polar component of surface free energy (p = 0.000). These results indicated that leaf roughness, surface free energy, its components, and work-of-adhesion for water played important roles in hydrological characteristics, especially work-of-adhesion for water. PMID:25198355

  19. Decreased Toxicity of Bacillus thuringiensis subsp. israelensis to Mosquito Larvae after Contact with Leaf Litter

    PubMed Central

    Stalinski, Renaud; Kersusan, Dylann; Veyrenc, Sylvie; David, Jean-Philippe; Reynaud, Stéphane; Després, Laurence

    2012-01-01

    Bacillus thuringiensis subsp. israelensis is a bacterium producing crystals containing Cry and Cyt proteins, which are toxic for mosquito larvae. Nothing is known about the interaction between crystal toxins and decaying leaf litter, which is a major component of several mosquito breeding sites and represents an important food source. In the present work, we investigated the behavior of B. thuringiensis subsp. israelensis toxic crystals sprayed on leaf litter. In the presence of leaf litter, a 60% decrease in the amount of Cyt toxin detectable by immunology (enzyme-linked immunosorbent assays [ELISAs]) was observed, while the respective proportions of Cry toxins were not affected. The toxicity of Cry toxins toward Aedes aegypti larvae was not affected by leaf litter, while the synergistic effect of Cyt toxins on all B. thuringiensis subsp. israelensis Cry toxins was decreased by about 20% when mixed with leaf litter. The toxicity of two commercial B. thuringiensis subsp. israelensis strains (VectoBac WG and VectoBac 12AS) and a laboratory-produced B. thuringiensis subsp. israelensis strain decreased by about 70% when mixed with leaf litter. Taken together, these results suggest that Cyt toxins interact with leaf litter, resulting in a decreased toxicity of B. thuringiensis subsp. israelensis in litter-rich environments and thereby dramatically reducing the efficiency of mosquitocidal treatments. PMID:22610426

  20. Leaf physiognomy and climate: A multivariate analysis

    NASA Astrophysics Data System (ADS)

    Davis, J. M.; Taylor, S. E.

    1980-11-01

    Research has demonstrated that leaf physiognomy is representative of the local or microclimate conditions under which plants grow. The physiognomy of leaf samples from Oregon, Michigan, Missouri, Tennessee, and the Panama Canal Zone has been related to the microclimate using Walter diagrams and Thornthwaite water-budget data. A technique to aid paleoclimatologists in identifying the nature of the microclimate from leaf physiognomy utilizes statistical procedures to classify leaf samples into one of six microclimate regimes based on leaf physiognomy information available from fossilized samples.

  1. Plant structure predicts leaf litter capture in the tropical montane bromeliad Tillandsia turneri.

    PubMed

    Ospina-Bautista, F; Estévez Varón, J V

    2016-05-01

    Leaves intercepted by bromeliads become an important energy and matter resource for invertebrate communities, bacteria, fungi, and the plant itself. The relationship between bromeliad structure, defined as its size and complexity, and accumulated leaf litter was studied in 55 bromeliads of Tillandsia turneri through multiple regression and the Akaike information criterion. Leaf litter accumulation in bromeliads was best explained by size and complexity variables such as plant cover, sheath length, and leaf number. In conclusion, plant structure determines the amount of litter that enters bromeliads, and changes in its structure could affect important processes within ecosystem functioning or species richness. PMID:27143067

  2. Leaf herbivory and nutrients increase nectar alkaloids.

    PubMed

    Adler, Lynn S; Wink, Michael; Distl, Melanie; Lentz, Amanda J

    2006-08-01

    Correlations between traits may constrain ecological and evolutionary responses to multispecies interactions. Many plants produce defensive compounds in nectar and leaves that could influence interactions with pollinators and herbivores, but the relationship between nectar and leaf defences is entirely unexplored. Correlations between leaf and nectar traits may be mediated by resources and prior damage. We determined the effect of nutrients and leaf herbivory by Manduca sexta on Nicotiana tabacum nectar and leaf alkaloids, floral traits and moth oviposition. We found a positive phenotypic correlation between nectar and leaf alkaloids. Herbivory induced alkaloids in nectar but not in leaves, while nutrients increased alkaloids in both tissues. Moths laid the most eggs on damaged, fertilized plants, suggesting a preference for high alkaloids. Induced nectar alkaloids via leaf herbivory indicate that species interactions involving leaf and floral tissues are linked and should not be treated as independent phenomena in plant ecology or evolution. PMID:16913940

  3. Sliding Wear Response of a Bronze Bushing: Influence of Applied Load and Test Environment

    NASA Astrophysics Data System (ADS)

    Prasad, B. K.

    2012-10-01

    This investigation pertains to the examination of the sliding wear behavior of a leaded-tin bronze bushing under the conditions of varying applied loads and test environments against a steel shaft. The test environment was changed by adding 5% of solid lubricants like talc and lead to an oil lubricant separately as well as in combination; the fraction of the two (solid) lubricants within the solid lubricant mixture was varied in the range of 25-75% in the latter case. The wear performance of the bushing was characterized in terms of the wear rate, frictional heating, and friction coefficient. The increasing load led to deterioration in the wear response, while the addition of the solid lubricant particles produced a reverse effect. Further, an appreciable difference in the wear behavior was not observed when the tests were conducted in the oil plus talc and oil plus lead lubricant mixtures. However, the oil containing lead and talc together brought about a significant improvement in the wear response; best results were obtained in the case of the lubricant mixture consisting of lead and talc together in the ratio of 3:1 in the oil. The observed wear behavior of the samples has been discussed in terms of specific characteristics of various microconstituents. The features of the wear surfaces and subsurface regions further substantiated the wear response and enabled us to understand the operating material removal mechanisms.

  4. Stratospheric Ozone destruction by the Bronze-Age Minoan eruption (Santorini Volcano, Greece)

    PubMed Central

    Cadoux, Anita; Scaillet, Bruno; Bekki, Slimane; Oppenheimer, Clive; Druitt, Timothy H.

    2015-01-01

    The role of volcanogenic halogen-bearing (i.e. chlorine and bromine) compounds in stratospheric ozone chemistry and climate forcing is poorly constrained. While the 1991 eruption of Pinatubo resulted in stratospheric ozone loss, it was due to heterogeneous chemistry on volcanic sulfate aerosols involving chlorine of anthropogenic rather than volcanogenic origin, since co-erupted chlorine was scavenged within the plume. Therefore, it is not known what effect volcanism had on ozone in pre-industrial times, nor what will be its role on future atmospheres with reduced anthropogenic halogens present. By combining petrologic constraints on eruption volatile yields with a global atmospheric chemistry-transport model, we show here that the Bronze-Age ‘Minoan’ eruption of Santorini Volcano released far more halogens than sulfur and that, even if only 2% of these halogens reached the stratosphere, it would have resulted in strong global ozone depletion. The model predicts reductions in ozone columns of 20 to >90% at Northern high latitudes and an ozone recovery taking up to a decade. Our findings emphasise the significance of volcanic halogens for stratosphere chemistry and suggest that modelling of past and future volcanic impacts on Earth’s ozone, climate and ecosystems should systematically consider volcanic halogen emissions in addition to sulfur emissions. PMID:26206616

  5. Fractionalization beyond Luttinger Liquid in the spectroscopy of Lithium Purple Bronze

    NASA Astrophysics Data System (ADS)

    Natalia, Lera; Jose, Alvarez

    We offer an interpretation for the departures of ARPES and STS spectroscopies experiments in quasi-one-dimensional Lithium Purple Bronze (LiPB) from single-band Luttinger Liquid (LL) theory. We base our calculation on a phenomenological description of the published data proposed in the original experiments and consider two bands crossing the Fermi level. We discuss the breakdown of the LL scaling relation η = α - 1 , the separation of the spinon edge and the holon peak, the phenomenological TL fit to the Energy Distribution Curves (EDC) and the survival of power-like density of states down to 4K. We consider non-critical fluctuations in one of the separated modes in which the electron fractionalize, and discuss under which conditions could be related with the upturn in the resistivity at 20-30K. We discuss the possibility of a gap in such separated mode and its role on the robust one-dimensional behavior. The connection with the proposed triplet superconductivity is at T = 1 . 4 K is also studied. We acknowledge financial support from MINECO FIS2012-37549-C05-03.

  6. Characterization of polymorphic microsatellite markers and genetic diversity in wild bronze featherback, Notopterus notopterus (Pallas, 1769).

    PubMed

    Gupta, Arti; Lal, Kuldeep K; Punia, Peyush; Singh, Rajeev K; Mohindra, Vindhya; Sah, Rama S; Kumar, Rajesh; Luhariya, Rupesh K; Dwivedi, Arvind K; Masih, Prachi; Mishra, R M; Jena, J K

    2013-12-01

    Six polymorphic microsatellite DNA loci were identified in the primitive fish, bronze featherback, Notopterus notopterus for the first time and demonstrated significant population genetic structure. Out of the six primers, one primer (NN90) was specific to N. notopterus (microsatellite sequence within the RAG1 gene) and five primers were product of successful cross-species amplification. Sixty-four primers available from 3 fish species of order Osteoglossiformes and families Notopteridae and Osteoglossidae were tested to amplify homologous microsatellite loci in N. notopterus. Fifteen primer pairs exhibited successful cross-priming PCR product. However, polymorphism was detected only at five loci. To assess the significance of these six loci (including NN90) in population genetic study, 215 samples of N. notopterus from five rivers, viz Satluj, Gomti, Yamuna, Brahmaputra and Mahanadi were analyzed. The five sample sets displayed different diversity levels and observed heterozygosity ranged from 0.6036 to 0.7373. Significant genotype heterogeneity (P < 0.0001) and high FST (0.2205) over all loci indicated that the samples are not drawn from the same genepool. The identified microsatellite loci are promising for use in fine-scale population structure analysis of N. notopterus. PMID:24072656

  7. Bronze-2 Gene Expression and Intron Splicing Patterns in Cells and Tissues of Zea mays L.

    PubMed

    Nash, J; Walbot, V

    1992-09-01

    A large fraction of the transcripts of the Bronze-2 (Bz2) gene of maize (Zea mays L.) are unspliced in purple husk tissues. The accumulation of unspliced messages could have destructive potential if the intron-bearing mRNAs are translated into aberrant proteins. Our initial studies suggested that both genetic and physiological factors may influence the degree of splicing failure. Nuclear background rather than cis-sequence effects is shown to contribute to the genetic component. The accumulation of unspliced message does not appear to be directly influenced by diurnal effects on transcript abundance, by the expression level of the Bz2 gene, or by thermal stress. We also show that maize cell cultures (Black Mexican Sweet, BMS) can be used to examine the molecular details involved in splicing failure. Much like whole maize plants, the BMS cells excise the Bz2 intron with varying degrees of efficiency. In contrast with heterologous constructs containing plant introns, splicing of the native Bz2 intron can appproach 100% in BMS cells. Splicing of transcripts from a marked, introduced gene can be compared to the endogeneous Bz2 gene facilitating analysis of the impact of sequence changes. PMID:16652984

  8. Origin of ferroelectric polarization in tetragonal tungsten-bronze-type oxides

    NASA Astrophysics Data System (ADS)

    Olsen, Gerhard Henning; Aschauer, Ulrich; Spaldin, Nicola A.; Selbach, Sverre Magnus; Grande, Tor

    2016-05-01

    The origin of ferroelectric polarization in tetragonal tungsten-bronze- (TTB-) type oxide strontium barium niobate (SBN) is investigated using first-principles density functional calculations. We study in particular the relationship between the polarization and the cation and vacancy ordering on alkali-earth metal lattice sites. Lattice dynamical calculations for paraelectric structures demonstrate that all cation configurations that can be accommodated in a 1 ×1 ×2 supercell result in a single unstable polar phonon, composed primarily of relative Nb-O displacements along the polar axis, as their dominant instability. The majority of the configurations also have a second octahedral tilt-mode instability which couples weakly to the polar mode. The existence of the tilt mode is strongly dependent on the local cation ordering, consistent with the fact that it is not found experimentally. Our results suggest that ferroelectricity in the SBN system is driven by a conventional second-order Jahn-Teller mechanism caused by the d0 Nb5 + cations, and demonstrate the strong influence of the size of Sr and Ba on the lattice distortions associated with polarization and octahedral tilting. Finally, we suggest a mechanism for the relaxor behavior in Sr-rich SBN based on Sr displacement inside pentagonal channels in the TTB structure.

  9. The questionable contribution of the Neolithic and the Bronze Age to European craniofacial form

    PubMed Central

    Brace, C. Loring; Seguchi, Noriko; Quintyn, Conrad B.; Fox, Sherry C.; Nelson, A. Russell; Manolis, Sotiris K.; Qifeng, Pan

    2006-01-01

    Many human craniofacial dimensions are largely of neutral adaptive significance, and an analysis of their variation can serve as an indication of the extent to which any given population is genetically related to or differs from any other. When 24 craniofacial measurements of a series of human populations are used to generate neighbor-joining dendrograms, it is no surprise that all modern European groups, ranging all of the way from Scandinavia to eastern Europe and throughout the Mediterranean to the Middle East, show that they are closely related to each other. The surprise is that the Neolithic peoples of Europe and their Bronze Age successors are not closely related to the modern inhabitants, although the prehistoric/modern ties are somewhat more apparent in southern Europe. It is a further surprise that the Epipalaeolithic Natufian of Israel from whom the Neolithic realm was assumed to arise has a clear link to Sub-Saharan Africa. Basques and Canary Islanders are clearly associated with modern Europeans. When canonical variates are plotted, neither sample ties in with Cro-Magnon as was once suggested. The data treated here support the idea that the Neolithic moved out of the Near East into the circum-Mediterranean areas and Europe by a process of demic diffusion but that subsequently the in situ residents of those areas, derived from the Late Pleistocene inhabitants, absorbed both the agricultural life way and the people who had brought it. PMID:16371462

  10. The questionable contribution of the Neolithic and the Bronze Age to European craniofacial form.

    PubMed

    Brace, C Loring; Seguchi, Noriko; Quintyn, Conrad B; Fox, Sherry C; Nelson, A Russell; Manolis, Sotiris K; Qifeng, Pan

    2006-01-01

    Many human craniofacial dimensions are largely of neutral adaptive significance, and an analysis of their variation can serve as an indication of the extent to which any given population is genetically related to or differs from any other. When 24 craniofacial measurements of a series of human populations are used to generate neighbor-joining dendrograms, it is no surprise that all modern European groups, ranging all of the way from Scandinavia to eastern Europe and throughout the Mediterranean to the Middle East, show that they are closely related to each other. The surprise is that the Neolithic peoples of Europe and their Bronze Age successors are not closely related to the modern inhabitants, although the prehistoric/modern ties are somewhat more apparent in southern Europe. It is a further surprise that the Epipalaeolithic Natufian of Israel from whom the Neolithic realm was assumed to arise has a clear link to Sub-Saharan Africa. Basques and Canary Islanders are clearly associated with modern Europeans. When canonical variates are plotted, neither sample ties in with Cro-Magnon as was once suggested. The data treated here support the idea that the Neolithic moved out of the Near East into the circum-Mediterranean areas and Europe by a process of demic diffusion but that subsequently the in situ residents of those areas, derived from the Late Pleistocene inhabitants, absorbed both the agricultural life way and the people who had brought it. PMID:16371462

  11. The examination, analysis and conservation of a bronze Egyptian Horus statuette

    NASA Astrophysics Data System (ADS)

    Smith, A.; Botha, H.; de Beer, F. C.; Ferg, E.

    2011-09-01

    The production techniques, corrosive deterioration, conservation and questions regarding authenticity of a small Egyptian bronze statuette of the Child Horus (in the collection of the Ditsong: National Museum of Cultural History in Pretoria) was scientifically examined and analysed. The statuette dates to Egypt's 12th Dynasty. When the statuette was damaged, it was considered the appropriate time to obtain valuable information about its history and background through scientific research. Neutron tomography (NT), a relatively new non-destructive technique (NDT) to the South African R&D community to study museum objects, was applied to perform this research. The results from NT were supported by additional tests done through XRF and XRD analyses of samples taken from the damaged statuette. Results revealed that the lost-wax method was used in the manufacturing process. The extent of the restoration and materials used can be verified and as a result the deterioration of the object can now be monitored. This paper describes in detail the analytical techniques used in the study and how it contributed to the conservation of the statuette and its authenticity.

  12. Genetic evidence for an origin of the Armenians from Bronze Age mixing of multiple populations.

    PubMed

    Haber, Marc; Mezzavilla, Massimo; Xue, Yali; Comas, David; Gasparini, Paolo; Zalloua, Pierre; Tyler-Smith, Chris

    2016-06-01

    The Armenians are a culturally isolated population who historically inhabited a region in the Near East bounded by the Mediterranean and Black seas and the Caucasus, but remain under-represented in genetic studies and have a complex history including a major geographic displacement during World War I. Here, we analyse genome-wide variation in 173 Armenians and compare them with 78 other worldwide populations. We find that Armenians form a distinctive cluster linking the Near East, Europe, and the Caucasus. We show that Armenian diversity can be explained by several mixtures of Eurasian populations that occurred between ~3000 and ~2000 bce, a period characterized by major population migrations after the domestication of the horse, appearance of chariots, and the rise of advanced civilizations in the Near East. However, genetic signals of population mixture cease after ~1200 bce when Bronze Age civilizations in the Eastern Mediterranean world suddenly and violently collapsed. Armenians have since remained isolated and genetic structure within the population developed ~500 years ago when Armenia was divided between the Ottomans and the Safavid Empire in Iran. Finally, we show that Armenians have higher genetic affinity to Neolithic Europeans than other present-day Near Easterners, and that 29% of Armenian ancestry may originate from an ancestral population that is best represented by Neolithic Europeans. PMID:26486470

  13. On the energetics of cation ordering in tungsten-bronze-type oxides.

    PubMed

    Olsen, Gerhard Henning; Selbach, Sverre Magnus; Grande, Tor

    2015-11-11

    Oxides with the tetragonal tungsten bronze (TTB) structure are well-known ferroelectrics that show a large flexibility both with respect to chemical composition and cation ordering. Two of the simplest compounds in this family are lead metaniobate (PbNb2O6 or PN) and strontium barium niobate (SrxBa1-xNb2O6 or SBN). While PN is a classical ferroelectric, SBN goes from ferroelectric to relaxor-like with increasing Sr content, with a polar direction different from that in PN. The partially occupied sublattices in both systems give the possibility for cation order-disorder phenomena, but it is not known if or how this influences the polarization and ferroelectricity. Here, we use density functional theory (DFT) calculations to investigate how cation and cation vacancy ordering influences the energetics of these compounds, by comparing both the energy differences and the barriers for transition between different cation configurations. We extend the thermodynamic model of O'Neill and Navrotsky, originally developed for cation interchange in spinels, to describe the order-disorder phenomenology in TTB oxides. The influence of order-disorder processes on the functional properties of PN and SBN is discussed. PMID:26508333

  14. A family of rare earth molybdenum bronzes: Oxides consisting of periodic arrays of interacting magnetic units

    NASA Astrophysics Data System (ADS)

    Schneemeyer, L. F.; Siegrist, T.; Besara, T.; Lundberg, M.; Sun, J.; Singh, D. J.

    2015-07-01

    The family of rare earth molybdenum bronzes, reduced ternary molybdates of composition LnMo16O44, was synthesized and a detailed structural study carried out. Bond valence sum (BVS) calculations clearly show that the molybdenum ions in tetrahedral coordination are hexavalent while the electron count in the primitive unit cell is odd. Yet, measurements show that the phases are semiconductors. The temperature dependence of the magnetic susceptibility of samples containing several different rare earth elements was measured. These measurements verified the presence of a 6.5 K magnetic phase transition not arising from the rare earth constituent, but likely associated with the unique isolated ReO3-type Mo8O36 structural subunits in this phase. To better understand the behavior of these materials, electronic structure calculations were performed within density functional theory. Results suggest a magnetic state in which these structural moieties have an internal ferromagnetic arrangement, with small ~1/8 μB moments on each Mo. We suggest that the Mo8O36 units behave like pseudoatoms with spin 1/2 derived from a single hole distributed over the eight Mo atoms that are strongly hybridized with the O atoms of the subunit. Interestingly, while the compound is antiferromagnetic, our calculations suggest that a field-stabilized ferromagnetic state, if achievable, will be a narrow band half-metal.

  15. Leather material found on a 6th B.C. Chinese bronze sword: a technical study.

    PubMed

    Luo, Wugan; Si, Yi; Wang, Hongmin; Qin, Ying; Huang, Fengchun; Wang, Changsui

    2011-09-01

    During July to November, 2006, an important archaeological excavation was conducted in Yun country, Hubei province, southern China. Chinese archaeologists found some remnant of leather materials, covered with red pigments, on a 6th century B.C. Chinese bronze sword. To understand the technology/ies that may have been utilized for manufacturing the leathers, a combined of Raman spectroscopy, FT-IR and XRF was thus applied to the remnant of leather materials. Raman analyses showed that red pigment on the leather was cinnabar (HgS). FT-IR and XRF analyses indicated that the content of some elements, such as Ca (existing as CaCO3) and Fe (existing as Fe2O3), were much higher than those in the surrounding grave soil. The results inferred an application of lime depilation and retting, and the Fe-Al compound salt as tanning agent. And it was furthermore implicated that the Fe-Al salt tanning technique had been developed in the middle and late Spring and Autumn Period of China. PMID:21703919

  16. Microstructural modification of as-cast NiAl bronze by friction stir processing

    NASA Astrophysics Data System (ADS)

    Oh-Ishi, Keiichiro; McNelley, Terry R.

    2004-09-01

    The application of friction stir processing (FSP) to a cast NiAl bronze (NAB) material is presented as a means for selective modification of the near-surface layers by converting as-cast microstructures to a wrought condition in the absence of macroscopic shape change. This may enable selective surface hardening of cast components. The complex physical metallurgy of the NAB is reviewed, and microstructure changes associated with FSP for a selected set of processing parameters are examined by optical microscopy (OM) and transmission electron microscopy (TEM) methods. Direct temperature measurement in the stir zone is infeasible and, so, these microstructure changes are used to estimate peak temperatures in the stir zone. The persistence of a Fe3Al phase ( κ ii) indicates that peak temperatures are below the solvus for this phase, while the presence of transformation products of the β phase, including fine Widmanstätten α, bainite, and martensite, indicates that peak temperatures exceed the eutectoid temperature for the reaction β → α+ κ iii throughout the stir zone.

  17. Computed tomography of a medium size Roman bronze statue of Cupid

    NASA Astrophysics Data System (ADS)

    Bettuzzi, M.; Casali, F.; Morigi, M. P.; Brancaccio, R.; Carson, D.; Chiari, G.; Maish, J.

    2015-03-01

    Diagnostics based on X-ray computed tomography (CT) are becoming increasingly important, not only in the medical field but in industry and cultural heritage. CT devices typical for medical applications, however, can seldom be used on art objects because both they are not easily transportable and they often present high X-ray absorption. It is therefore necessary to make use of portable instrumentation and/or to develop tomographic systems optimized to the characteristics of the objects under examination. This work describes the computed tomography of a first century A.D. Roman bronze statue of Cupid (96.AB.53) in the collection of the J. Paul Getty Museum, within the collaborative framework between the Getty Conservation Institute and the Department of Physics and Astronomy (DIFA) of the University of Bologna (Italy). The tomography performed at the Getty facilities employed a 450 kV X-ray tube and a detection system developed at DIFA. The study highlighted the casting and construction techniques used by Roman foundry workers and provided information on the status of conservation of the statue. A 3D virtual reconstruction allowed the user to define different cross-sections enabling the study of the internal features.

  18. Stratospheric Ozone destruction by the Bronze-Age Minoan eruption (Santorini Volcano, Greece)

    NASA Astrophysics Data System (ADS)

    Cadoux, Anita; Scaillet, Bruno; Bekki, Slimane; Oppenheimer, Clive; Druitt, Timothy H.

    2015-07-01

    The role of volcanogenic halogen-bearing (i.e. chlorine and bromine) compounds in stratospheric ozone chemistry and climate forcing is poorly constrained. While the 1991 eruption of Pinatubo resulted in stratospheric ozone loss, it was due to heterogeneous chemistry on volcanic sulfate aerosols involving chlorine of anthropogenic rather than volcanogenic origin, since co-erupted chlorine was scavenged within the plume. Therefore, it is not known what effect volcanism had on ozone in pre-industrial times, nor what will be its role on future atmospheres with reduced anthropogenic halogens present. By combining petrologic constraints on eruption volatile yields with a global atmospheric chemistry-transport model, we show here that the Bronze-Age ‘Minoan’ eruption of Santorini Volcano released far more halogens than sulfur and that, even if only 2% of these halogens reached the stratosphere, it would have resulted in strong global ozone depletion. The model predicts reductions in ozone columns of 20 to >90% at Northern high latitudes and an ozone recovery taking up to a decade. Our findings emphasise the significance of volcanic halogens for stratosphere chemistry and suggest that modelling of past and future volcanic impacts on Earth’s ozone, climate and ecosystems should systematically consider volcanic halogen emissions in addition to sulfur emissions.

  19. The ``Madonna di Loreto'' Bronze Age Sanctuary and its Stone Calendar

    NASA Astrophysics Data System (ADS)

    Tunzi, A.; Zupone, M. L.; Antonello, E.

    2009-08-01

    The ``Madonna di Loreto'' (Trinitapoli, Puglia) site is the largest Bronze Age sanctuary presently known in Italy. Inside its area, several hypogeal structures excavated in the calcareous rock and devoted to ritual use were found. The most impressive manifestation of the cult is however a set of more than 1000 circular holes, aligned in rows and covering the whole sacred area. The holes were excavated during many centuries, following a rigid plan and taking into account specific celestial points. The archaeoastronomical study of the rows revealed three main alignments: that with the highest frequency, i.e. with the highest number of holes, is along the meridian, thus referring to astronomical phenomena with a daily periodicity; that with an intermediate frequency to a phenomenon with annual periodicity (the azimuth of the sunrise on a peculiar day, near to the summer solstice), and that with the lowest frequency to the South major lunistice, a phenomenon with a long term (18.6 years) periodicity. This agreement has a very high statistical significance and it allows us to interpret the hole rows as elements of a complex calendric system with a ritual character.

  20. Microstructure, microhardness and dry friction behavior of cold-sprayed tin bronze coatings

    NASA Astrophysics Data System (ADS)

    Guo, Xueping; Zhang, Ga; Li, Wen-Ya; Dembinski, Lucas; Gao, Yang; Liao, Hanlin; Coddet, Christian

    2007-12-01

    In this paper, two types of tin bronze coatings (Cu-6 wt.% Sn and Cu-8 wt.% Sn) were prepared by cold spray process. The as-sprayed coatings were subjected to a vacuum heat treatment at 600 °C for 3 h. The coating microstructure, microhardness and tribological performance were characterized. The effects of the tin content and the vacuum heat treatment on the microstructure, microhardness and tribological behavior of the coatings were investigated. It is found that the as-sprayed CuSn6 (As6) and CuSn8 (As8) coatings exhibit practically an identical porosity. Meanwhile, As8 presents a higher microhardness than As6. In addition, the increase of the tin content in the powder feedstock leads to a lower wear rate. After a heat treatment, coating porosities are significantly reduced. However, the coating hardness is significantly decreased and the coating presents a much decreased wear resistance. For the as-sprayed coatings, such factors as ploughing and particle delamination could determine the sliding process. The heat treatment results in a distinct modification of the tribological behavior. For the annealed coatings, the adhesion, between the coating and the counterpart, could play a dominant role in the sliding process.