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Sample records for silene latifolia electronic

  1. Dioecious Silene latifolia plants show sexual dimorphism in the vegetative stage

    Czech Academy of Sciences Publication Activity Database

    Žlůvová, Jitka; Žák, Jiří; Janoušek, Bohuslav; Vyskot, Boris

    2010-01-01

    Roč. 10, č. 208 (2010), s. 1-5 ISSN 1471-2229 R&D Projects: GA AV ČR(CZ) KJB600040801; GA AV ČR(CZ) IAA600040801; GA ČR(CZ) GAP501/10/0102 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : sex dimorphism * Silene latifolia * dioecious plants Subject RIV: BO - Biophysics Impact factor: 4.085, year: 2010

  2. Identification of a Novel Retrotransposon with Sex Chromosome-Specific Distribution in Silene latifolia

    Czech Academy of Sciences Publication Activity Database

    Králová, Tereza; Čegan, Radim; Kubát, Zdeněk; Vrána, Jan; Vyskot, Boris; Vogel, Ivan; Kejnovský, Eduard; Hobza, Roman

    2014-01-01

    Roč. 143, 1-3 (2014), s. 87-95 ISSN 1424-8581 R&D Projects: GA MŠk(CZ) LM2010005; GA ČR(CZ) GAP501/10/0102; GA ČR(CZ) GAP501/12/2220; GA ČR(CZ) GAP305/10/0930; GA ČR(CZ) GA522/09/0083; GA MŠk(CZ) LO1204 Institutional support: RVO:68081707 Keywords : Microdissection * Sex chromosomes * Silene latifolia (white campion) Subject RIV: BO - Biophysics; EF - Botanics (UEB-Q) Impact factor: 1.561, year: 2014

  3. Comparative analysis of a plant pseudoautosomal region (PAR) in Silene latifolia with the corresponding S. vulgaris autosome

    Czech Academy of Sciences Publication Activity Database

    Blavet, N.; Blavet, Hana; Čegan, Radim; Zemp, N.; Ždánská, Jana; Janoušek, Bohuslav; Hobza, Roman; Widmer, A.

    2012-01-01

    Roč. 13, č. 226 (2012), s. 1-9 ISSN 1471-2164 R&D Projects: GA ČR(CZ) GA522/09/0083; GA ČR GBP501/12/G090 Institutional research plan: CEZ:AV0Z50040702 Keywords : BAC library * pseudoautosomal region * Silene latifolia Subject RIV: BO - Biophysics Impact factor: 4.397, year: 2012

  4. Coping with third parties in a nursery pollination mutualism: Hadena bicruris avoids oviposition on pathogen-infected, less rewarding Silene latifolia

    NARCIS (Netherlands)

    Biere, A.; Honders, S.C.

    2006-01-01

    In nursery pollination systems, pollinator offspring usually feed on pollinated fruits or seeds. Costs and benefits of the interaction for plant and pollinator, and hence its local outcome (antagonismmutualism), can be affected by the presence of 'third-party' species. Infection of Silene latifolia

  5. Genomic diversity in two related plant species with and without sex chromosomes--Silene latifolia and S. vulgaris.

    Directory of Open Access Journals (Sweden)

    Radim Cegan

    Full Text Available Genome size evolution is a complex process influenced by polyploidization, satellite DNA accumulation, and expansion of retroelements. How this process could be affected by different reproductive strategies is still poorly understood.We analyzed differences in the number and distribution of major repetitive DNA elements in two closely related species, Silene latifolia and S. vulgaris. Both species are diploid and possess the same chromosome number (2n = 24, but differ in their genome size and mode of reproduction. The dioecious S. latifolia (1C = 2.70 pg DNA possesses sex chromosomes and its genome is 2.5× larger than that of the gynodioecious S. vulgaris (1C = 1.13 pg DNA, which does not possess sex chromosomes. We discovered that the genome of S. latifolia is larger mainly due to the expansion of Ogre retrotransposons. Surprisingly, the centromeric STAR-C and TR1 tandem repeats were found to be more abundant in S. vulgaris, the species with the smaller genome. We further examined the distribution of major repetitive sequences in related species in the Caryophyllaceae family. The results of FISH (fluorescence in situ hybridization on mitotic chromosomes with the Retand element indicate that large rearrangements occurred during the evolution of the Caryophyllaceae family.Our data demonstrate that the evolution of genome size in the genus Silene is accompanied by the expansion of different repetitive elements with specific patterns in the dioecious species possessing the sex chromosomes.

  6. Effects of pollination timing and distance on seed production in a dioecious weed Silene latifolia

    Science.gov (United States)

    Anderson, Jay F.; Duddu, Hema S. N.; Shirtliffe, Steven J.; Benaragama, Dilshan; Syrovy, Lena D.; Stanley, Katherine A.; Haile, Teketel A.

    2015-11-01

    Silene latifolia Poir. (white cockle or white campion) is an important invasive weed in North American agriculture. It exhibits dioecy, therefore, both male and female plants are required in order for seed production to occur. However, dioecious species being invasive is not common because of their limitations in pollination and subsequent seed production. The objective of this study is to determine the effect of pollination timing and distance on seed production of Silene latifolia. A series of experiments including pollination exclusion, timing and pollination distance were conducted in 2009 and 2010 at or around Saskatoon, Saskatchewan. For pollination exclusion, exclosures were built around the natural female plants for exclosure, sham-exclosure, and male and female combined treatments. Pollination timing was studied by applying exclosure, non-exclosure, night-exclosure, and day-exclosure treatments to individual female plants. Female plants were transplanted along a linear interval at six different distances from the pollen source to study the effect of pollination distance. S. latifolia was exclusively insect-pollinated and pollination occurred both day and night; however, in one year, pollination occurred mainly at night. Female plants that were in the range of 0-4 m from a compatible pollen source experienced no limitation to pollination. However, when the distance was increased further up to 128 m, pollination levels and subsequent seed production were declined. Moreover, there were differences in seed production between years suggesting that pollination was affected by the environmental conditions during pollination and the crop that white cockle was grown in. These experiments indicate that seed production in S. latifolia is limited by insect-pollination. Although there was pollination limitation for seed production at greater distances from a pollen source, the high fecundity rate (3000-18000 seeds per plant) resulted in a large seed output. Thus, we

  7. Intraspecific competition and mating between fungal strains of the anther smut Microbotryum violaceum from the host plants Silene latifolia and S-dioica.

    NARCIS (Netherlands)

    Van Putten, W.F.; Biere, A.; Van Damme, J.M.M.

    2003-01-01

    We studied intraspecific competition and assortative mating between strains of the anther smut fungus Microbotryum violaceum from two of its host species, Silene latifolia and S. dioica. Specifically, we investigated whether strains from allopatric host populations have higher competitive ability on

  8. Intraspecific competition and mating between fungal strains of the anther smut Microbotryum violaceum from the host plants Silene latifolia and S-dioica

    NARCIS (Netherlands)

    Van Putten, WF; Biere, A; Van Damme, JMM

    We studied intraspecific competition and assortative mating between strains of the anther smut fungus Microbotryum violaceum from two of its host species, Silene latifolia and S. dioica. Specifically. we investigated whether strains from allopatric host populations have higher competitive ability on

  9. Next Generation Sequencing-Based Analysis of Repetitive DNA in the Model Dioceous Plant Silene latifolia

    Czech Academy of Sciences Publication Activity Database

    Macas, Jiří; Kejnovský, Eduard; Neumann, Pavel; Novák, Petr; Koblížková, Andrea; Vyskot, Boris

    2011-01-01

    Roč. 6, č. 11 (2011), e27335 E-ISSN 1932-6203 R&D Projects: GA MŠk(CZ) OC10037; GA MŠk(CZ) LC06004; GA MŠk(CZ) LH11058; GA ČR(CZ) GAP501/10/0102; GA ČR(CZ) GAP305/10/0930 Institutional research plan: CEZ:AV0Z50510513; CEZ:AV0Z50040702 Keywords : Plant genome * Sequencing-Based Analyses * Repetitive DNA * Silene latifolia Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.092, year: 2011

  10. Host-related genetic differentiation in the anther smut fungus Microbotryum violaceum in sympatric, parapatric and allopatric populations of two host species Silene latifolia and S. dioica

    NARCIS (Netherlands)

    Van Putten, W.F.; Biere, A.; Van Damme, J.M.M.

    2005-01-01

    We investigated genetic diversity in West European populations of the fungal pathogen Microbotryum violaceum in sympatric, parapatric and allopatric populations of the host species Silene latifolia and S. dioica, using four polymorphic microsatellite loci. In allopatric host populations, the fungus

  11. Host-related genetic differentiation in the anther smut fungus Microbotryum violaceum in sympatric, parapatric and allopatric populations of two host species Silene latifolia and S-dioica

    NARCIS (Netherlands)

    Van Putten, WF; Biere, A; Van Damme, JMM

    We investigated genetic diversity in West European populations of the fungal pathogen Microbotryum violaceum in sympatric, parapatric and allopatric populations of the host species Silene latifolia and S. dioica, using four polymorphic microsatellite loci. In allopatric host populations, the fungus

  12. Spatial expression dynamics of Men-9 delineate the third floral whorl in male and female flowers of dioecious Silene latifolia.

    Science.gov (United States)

    Robertson, S E; Li, Y; Scutt, C P; Willis, M E; Gilmartin, P M

    1997-07-01

    Sex determination in Silene latifolia is controlled by heteromorphic sex chromosomes. Female flowers have five fused carpels and ten arrested stamen primordia. The male-determining Y chromosome overrides female development to suppress carpel formation and promote stamen development. The isolation and characterization of two S. latifolia. Male enhanced cDNAs, Men-9a and Men-9b, which probably represent different alleles of a novel gene are reported here. Men-9a and Men-9b share 91.8% coding sequence nucleotide identity, yet only 85.4% amino acid identity. The Men-9 cDNAs are related to the previously reported MROS3 cDNA from S. latifolia. However, MROS3 is not present in the S. latifolia population used in these studies and the expression dynamics of Men-9a and Men-9b contrast dramatically with those reported for MROS3. Men-9 cDNAs are expressed primarily in anthers of young male flowers, with highest expression in 1-2 mm buds. Men-9 expression is also observed at a low level in female flowers. In situ hybridization analysis reveals two phases of Men-9 expression. The first phase is during a common stage of early stamen development in male and female flowers prior to stamen arrest in female flowers. The second phase of Men-9 expression is maximal in the epidermis and endothecium of Y chromosome- and Ustilago violacea-induced stamens; expression in male and female flowers extends to the epidermis of the staminal nectaries with strict boundaries at the second and fourth whorls, Men-9 gene expression therefore delineates the boundaries of the third floral whorl in S. latifolia flowers.

  13. A new physical mapping approach refines the sex-determining gene positions on the Silene latifolia Y-chromosome

    Science.gov (United States)

    Kazama, Yusuke; Ishii, Kotaro; Aonuma, Wataru; Ikeda, Tokihiro; Kawamoto, Hiroki; Koizumi, Ayako; Filatov, Dmitry A.; Chibalina, Margarita; Bergero, Roberta; Charlesworth, Deborah; Abe, Tomoko; Kawano, Shigeyuki

    2016-01-01

    Sex chromosomes are particularly interesting regions of the genome for both molecular genetics and evolutionary studies; yet, for most species, we lack basic information, such as the gene order along the chromosome. Because they lack recombination, Y-linked genes cannot be mapped genetically, leaving physical mapping as the only option for establishing the extent of synteny and homology with the X chromosome. Here, we developed a novel and general method for deletion mapping of non-recombining regions by solving “the travelling salesman problem”, and evaluate its accuracy using simulated datasets. Unlike the existing radiation hybrid approach, this method allows us to combine deletion mutants from different experiments and sources. We applied our method to a set of newly generated deletion mutants in the dioecious plant Silene latifolia and refined the locations of the sex-determining loci on its Y chromosome map.

  14. Fungal Infection Induces Sex-Specific Transcriptional Changes and Alters Sexual Dimorphism in the Dioecious Plant Silene latifolia.

    Directory of Open Access Journals (Sweden)

    Niklaus Zemp

    2015-10-01

    Full Text Available Sexual dimorphism, including differences in morphology, behavior and physiology between females and males, is widespread in animals and plants and is shaped by gene expression differences between the sexes. Such expression differences may also underlie sex-specific responses of hosts to pathogen infections, most notably when pathogens induce partial sex reversal in infected hosts. The genetic changes associated with sex-specific responses to pathogen infections on the one hand, and sexual dimorphism on the other hand, remain poorly understood. The dioecious White Campion (Silene latifolia displays sexual dimorphism in floral traits and infection with the smut fungus Micobrotryum lychnidis-dioicae induces a partial sex reversal in females. We find strong sex-specific responses to pathogen infection and reduced sexual dimorphism in infected S. latifolia. This provides a direct link between pathogen-mediated changes in sex-biased gene expression and altered sexual dimorphism in the host. Expression changes following infection affected mainly genes with male-biased expression in healthy plants. In females, these genes were up-regulated, leading to a masculinization of the transcriptome. In contrast, infection in males was associated with down-regulation of these genes, leading to a demasculinization of the transcriptome. To a lesser extent, genes with female-biased expression in healthy plants were also affected in opposite directions in the two sexes. These genes were overall down-regulated in females and up-regulated in males, causing, respectively, a defeminization in infected females and a feminization of the transcriptome in infected males. Our results reveal strong sex-specific responses to pathogen infection in a dioecious plant and provide a link between pathogen-induced changes in sex-biased gene expression and sexual dimorphism.

  15. Fungal Infection Induces Sex-Specific Transcriptional Changes and Alters Sexual Dimorphism in the Dioecious Plant Silene latifolia.

    Science.gov (United States)

    Zemp, Niklaus; Tavares, Raquel; Widmer, Alex

    2015-10-01

    Sexual dimorphism, including differences in morphology, behavior and physiology between females and males, is widespread in animals and plants and is shaped by gene expression differences between the sexes. Such expression differences may also underlie sex-specific responses of hosts to pathogen infections, most notably when pathogens induce partial sex reversal in infected hosts. The genetic changes associated with sex-specific responses to pathogen infections on the one hand, and sexual dimorphism on the other hand, remain poorly understood. The dioecious White Campion (Silene latifolia) displays sexual dimorphism in floral traits and infection with the smut fungus Micobrotryum lychnidis-dioicae induces a partial sex reversal in females. We find strong sex-specific responses to pathogen infection and reduced sexual dimorphism in infected S. latifolia. This provides a direct link between pathogen-mediated changes in sex-biased gene expression and altered sexual dimorphism in the host. Expression changes following infection affected mainly genes with male-biased expression in healthy plants. In females, these genes were up-regulated, leading to a masculinization of the transcriptome. In contrast, infection in males was associated with down-regulation of these genes, leading to a demasculinization of the transcriptome. To a lesser extent, genes with female-biased expression in healthy plants were also affected in opposite directions in the two sexes. These genes were overall down-regulated in females and up-regulated in males, causing, respectively, a defeminization in infected females and a feminization of the transcriptome in infected males. Our results reveal strong sex-specific responses to pathogen infection in a dioecious plant and provide a link between pathogen-induced changes in sex-biased gene expression and sexual dimorphism.

  16. Patterns of molecular evolution in dioecious and non-dioecious Silene

    Czech Academy of Sciences Publication Activity Database

    Kaefer, J.; Talianová, Martina; Bigot, T.; Michu, Elleni; Gueguen, L.; Widmer, A.; Žlůvová, Jitka; Glemin, S.; Marais, G.A.B.

    2013-01-01

    Roč. 26, č. 2 (2013), s. 335-346 ISSN 1010-061X R&D Projects: GA ČR(CZ) GA521/08/0932; GA ČR(CZ) GD204/09/H002; GA ČR(CZ) GBP501/12/G090 Institutional support: RVO:68081707 Keywords : purifying selection * reproductive systems * Silene latifolia Subject RIV: BO - Biophysics Impact factor: 3.483, year: 2013

  17. Determinants of genetic structure in a nonequilibrium metapopulation of the plant Silene latifolia.

    Directory of Open Access Journals (Sweden)

    Peter D Fields

    Full Text Available Population genetic differentiation will be influenced by the demographic history of populations, opportunities for migration among neighboring demes and founder effects associated with repeated extinction and recolonization. In natural populations, these factors are expected to interact with each other and their magnitudes will vary depending on the spatial distribution and age structure of local demes. Although each of these effects has been individually identified as important in structuring genetic variance, their relative magnitude is seldom estimated in nature. We conducted a population genetic analysis in a metapopulation of the angiosperm, Silene latifolia, from which we had more than 20 years of data on the spatial distribution, demographic history, and extinction and colonization of demes. We used hierarchical Bayesian methods to disentangle which features of the populations contributed to among population variation in allele frequencies, including the magnitude and direction of their effects. We show that population age, long-term size and degree of connectivity all combine to affect the distribution of genetic variance; small, recently-founded, isolated populations contributed most to increase FST in the metapopulation. However, the effects of population size and population age are best understood as being modulated through the effects of connectivity to other extant populations, i.e. FST diminishes as populations age, but at a rate that depends how isolated the population is. These spatial and temporal correlates of population structure give insight into how migration, founder effect and within-deme genetic drift have combined to enhance and restrict genetic divergence in a natural metapopulation.

  18. Silene noctiflora L., present in the flora of Kosovo and Metohija (Serbia

    Directory of Open Access Journals (Sweden)

    Prodanović, D.

    2016-12-01

    Full Text Available The genus Silene (family Caryophyllaceae comprises more than 700 species and it is one of the larger genera of the World’s flora. Studying the flora of the plain part of Kosovo and Metohija, in the village of Gračanica, on the eastern rim of the Kosovo basin (approximately 10 km to the south of Priština, near the Gračanka stream, we identified a weed and ruderal species, Silene noctiflora. The part of the stream bank is urbanised and turned into a quay. The quay is regularly maintained implying that the banks are regularly weeded and the riverbeds are cleaned as the Typha latifolia species rapidly grows; it may be the reason why this species was not immediately detected and appropriately identified. Except for the afore mentioned locality, the species was also reported on the neglected arable fields and tilths, around the unkempt orchards, along the new tarmac road between Gračanica and Laplje Selo, on the locality called Labura. Silene noctiflora is not mentioned for the region of Kosovo and Metohija in the new and revised edition of the book Flora of Serbia 2.

  19. Substitution rates in the X- and Y-linked genes of the plants, Silene latifolia and S. dioica.

    Science.gov (United States)

    Filatov, Dmitry A; Charlesworth, Deborah

    2002-06-01

    Theory predicts that selection should be less effective in the nonrecombining genes of Y-chromosomes, relative to the situation for genes on the other chromosomes, and this should lead to the accumulation of deleterious nonsynonymous substitutions. In addition, synonymous substitution rates may differ between X- and Y-linked genes because of the male-driven evolution effect and also because of actual differences in per-replication mutation rates between the sex chromosomes. Here, we report the first study of synonymous and nonsynonymous substitution rates on plant sex chromosomes. We sequenced two pairs of sex-linked genes, SlX1-SlY1 and SlX4-SlY4, from dioecious Silene latifolia and S. dioica, and their non-sex-linked homologues from nondioecious S. vulgaris and Lychnis flos-jovis, respectively. The rate of nonsynonymous substitutions in the SlY4 gene is significantly higher than that in the SlX4 gene. Silent substitution rates are also significantly higher in both Y-linked genes, compared with their X-linked homologues. The higher nonsynonymous substitution rate in the SlY4 gene is therefore likely to be caused by a mutation rate difference between the sex chromosomes. The difference in silent substitution rates between the SlX4 and SlY4 genes is too great to be explained solely by a higher per-generation mutation rate in males than females. It is thus probably caused by a difference in per-replication mutation rates between the sex chromosomes. This suggests that the local mutation rate can change in a relatively short evolutionary time.

  20. Semi-automatic laser beam microdissection of the Y chromosome and analysis of Y chromosome DNA in a dioecious plant, Silene latifolia

    International Nuclear Information System (INIS)

    Matsunaga, S.; Kawano, S.; Michimoto, T.; Higashiyama, T.; Nakao, S.; Sakai, A.; Kuroiwa, T.

    1999-01-01

    Silene latifolia has heteromorphic sex chromosomes, the X and Y chromosomes. The Y chromosome, which is thought to carry the male determining gene, was isolated by UV laser microdissection and amplified by degenerate oligonucleotide-primed PCR. In situ chromosome suppression of the amplified Y chromosome DNA in the presence of female genomic DNA as a competitor showed that the microdissected Y chromosome DNA did not specifically hybridize to the Y chromosome, but-hybridized to all chromosomes. This result suggests that the Y chromosome does not contain Y chromosome-enriched repetitive sequences. A repetitive sequence in the microdissected Y chromosome, RMY1, was isolated while screening repetitive sequences in the amplified Y chromosome. Part of the nucleotide sequence shared a similarity to that of X-43.1, which was isolated from microdissected X chromosomes. Since fluorescence in situ hybridization analysis with RMY1 demonstrated that RMY1 was localized at the ends of the chromosome, RMY1 may be a subtelomeric repetitive sequence. Regarding the sex chromosomes, RMY1 was detected at both ends of the X chromosome and at one end near the pseudoautosomal region of the Y chromosome. The different localization of RMY1 on the sex chromosomes provides a clue to the problem of how the sex chromosomes arose from autosomes

  1. Structure and evolution of Apetala3, a sex-linked gene in Silene latifolia

    Czech Academy of Sciences Publication Activity Database

    Čegan, Radim; Marais, G.A.B.; Kubeková, Hana; Blavet, N.; Widmer, A.; Vyskot, Boris; Doležel, Jaroslav; Šafář, Jan; Hobza, Roman

    2010-01-01

    Roč. 10, č. 180 (2010), s. 1-10 ISSN 1471-2229 R&D Projects: GA ČR(CZ) GA522/09/0083; GA ČR(CZ) GD204/09/H002; GA AV ČR(CZ) KJB600040901 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702; CEZ:AV0Z50380511 Keywords : sex chromosomes evolution * Apetala3 * Silene Subject RIV: BO - Biophysics Impact factor: 4.085, year: 2010

  2. The slowdown of Y chromosome expansion in dioecious Silene latifolia due to DNA loss and male-specific silencing of retrotransposons

    Czech Academy of Sciences Publication Activity Database

    Puterova, Janka; Kubát, Zdeněk; Kejnovský, Eduard; Jesionek, Wojciech; Čížková, Jana; Vyskot, Boris; Hobza, Roman

    2018-01-01

    Roč. 19, FEB2018 (2018) ISSN 1471-2164 R&D Projects: GA ČR GJ15-21523Y Institutional support: RVO:68081707 ; RVO:61389030 Keywords : sex-linked genes * plant silene * transposable elements Subject RIV: EF - Botanics; EF - Botanics (UEB-Q) OBOR OECD: Plant sciences, botany; Plant sciences, botany (UEB-Q) Impact factor: 3.729, year: 2016

  3. Genomic diversity in two related plant species with and without sex chromosomes - Silene latifolia and S. vulgaris

    Czech Academy of Sciences Publication Activity Database

    Čegan, Radim; Vyskot, Boris; Kejnovský, Eduard; Kubát, Zdeněk; Blavet, Hana; Šafář, Jan; Doležel, Jaroslav; Blavet, N.; Hobza, Roman

    2012-01-01

    Roč. 7, č. 2 (2012), e31898 E-ISSN 1932-6203 R&D Projects: GA AV ČR(CZ) KJB600040901; GA ČR(CZ) GPP501/10/P483; GA ČR(CZ) GAP501/10/0102; GA ČR(CZ) GD204/09/H002; GA ČR(CZ) GAP305/10/0930; GA ČR(CZ) GA522/09/0083 Institutional research plan: CEZ:AV0Z50040702; CEZ:AV0Z50040507; CEZ:AV0Z50380511 Keywords : Silene * repetitive DNA * genome size Subject RIV: BO - Biophysics Impact factor: 3.730, year: 2012

  4. Inbreeding and oubreeding effects on pollen fitness and zygote survival in Silene nutans (Caryophyllaceae)

    DEFF Research Database (Denmark)

    Hauser, Thure Pavlo; Siegismund, H.R.

    2000-01-01

    inbreeding depression, oubreeding effects, outcrossing, pollen fitness, selfing, Silene nutans, zygote survival......inbreeding depression, oubreeding effects, outcrossing, pollen fitness, selfing, Silene nutans, zygote survival...

  5. Primula latifolia Lapeyr. and Primula vulgaris Hudson flavonoids.

    Science.gov (United States)

    Colombo, Paola S; Flamini, Guido; Fico, Gelsomina

    2014-01-01

    Three flavonoids were isolated from the leaf MeOH extracts of Primula latifolia Lapeyr. and Primula vulgaris Hudson collected from Italian Alps: rutin (1) and kaempferol 3-neohesperidoside (2) from P. latifolia, and kaempferol 3-β-O-glucopyranosyl-(1 → 2) gentiobioside (3) from P. vulgaris. The structures were assigned on the basis of their (1)H and (13)C NMR data, including those derived from 2D NMR, as well as on HPLC-MS results. This article is the first to report on P. vulgaris tissue flavonoids after Harborne's study in 1968 and the first work ever on these compounds from P. latifolia.

  6. Fuel solution criticality accident studies with the SILENE reactor: phenomenology, consequences and simulated intervention

    International Nuclear Information System (INIS)

    Barbry, F.

    1984-01-01

    After defining the content and the objectives of criticality accident studies, the SILENE reactor, a means of studying fuel solution criticality accidents, is presented. Information obtained from the CRAC and SILENE experimental programs are then presented; they concern power excursion phenomenology, radiological consequences, and finally guide-lines for current and future programs

  7. Research program and uses of the solution fueled reactor SILENE

    International Nuclear Information System (INIS)

    Barbry, F.; Ratel, R.

    1985-09-01

    Designed and operated by the Nuclear Protection and Safety Institute of the CEA, SILENE is an original small sized reactor fueled with an uranyl nitrate solution. The reactor is capable to operate in three modes: ''Pulse'' operation (high power levels up to 1000 Megawatts during several millisecond), ''Free evolution'' operation (simulation of criticality accident excursions), ''Steady state'' operation in a power range of 0.01 W to 1 kW. The core can be surrounded by appropriate shields (lead, polyethylene) to vary the leakage radiations and the gamma to neutron dose ratio. It's possible to insert in the central cavity of the annular core vessel some capsules, devices or samples to be submitted to very high radiations levels. The research activities are mainly devoted towards nuclear safety studies: the criticality accident studies, and the behavior of oxide fuels under transient conditions. Some examples of tests are presented. As to other applications of the SILENE facility, the main studies now in progress deal with: designing and calibration of Health physics intrumentation, neutron and gamma dosimetry, and, radiobiology. Once the characteristics of radiation field are qualified by calculations and experimental techniques, SILENE will be proposed as a reference source [fr

  8. Histone H4 acetylation patterns during seed germination and early plant development

    Czech Academy of Sciences Publication Activity Database

    Hodurková, Jaromíra; Vyskot, Boris

    2003-01-01

    Roč. 46, č. 1 (2003), s. 23-28 ISSN 0006-3134 R&D Projects: GA AV ČR IAA5004901 Institutional research plan: CEZ:AV0Z5004920 Keywords : epigenetic modification * Silene latifolia * transcription Subject RIV: BO - Biophysics Impact factor: 0.919, year: 2003

  9. Antimycotic Activity and Genotoxic Evaluation of Citrus sinensis and Citrus latifolia Essential Oils.

    Science.gov (United States)

    Ruiz-Pérez, Nancy J; González-Ávila, Marisela; Sánchez-Navarrete, Jaime; Toscano-Garibay, Julia D; Moreno-Eutimio, Mario A; Sandoval-Hernández, Teresa; Arriaga-Alba, Myriam

    2016-05-03

    The aim of this study was to evaluate the antifungal activity of essential oils (EOs) of Citrus sinensis (C. sinensis) and Citrus latifolia (C. latifolia) against five Candida species: Candida albicans, Candida tropicalis, Candida glabrata, Candida lusitaniae and Candida guilliermondii; and perform its genotoxic evaluation. The EOs of C. sinensis and C. latifolia were obtained from the peel by hydro-distillation. The major components determined by GC-MS were in C. sinensis, d-limonene (96%) and α-myrcene (2.79%); and in C. latifolia, d-limonene (51.64%), β-thujene (14.85%), β-pinene (12.79%) and γ-terpinene (12.8%). Antifungal properties were studied by agar diffusion method, where C. sinensis presented low activity and C. latifolia essential oil was effective to inhibit growing of C. lusitaniae and C. guilliermondii with IC50 of 6.90 and 2.92 μg respectively. The minimum inhibitory concentrations (MIC) for C. sinensis were in a range of 0.42-3.71 μg and for C. latifolia of 0.22-1.30 μg. Genotoxic evaluation was done by Ames test where none of the oils induced point mutations. Flow cytometry was used to measure toxicity in human oral epithelial cells, C. sinensis was not cytotoxic and C. latifolia was toxic at 21.8 μg. These properties might bestow different odontological applications to each essential oil.

  10. Observations of the ipogean part of Typha Latifolia and Phragmites Australis; Osservazioni sull'apparato ipogeo di Typha Latifolia e Phragmites Australis

    Energy Technology Data Exchange (ETDEWEB)

    Borin, M.; Bonaiti, G. [Padua Univ., Padua (Italy). Dipt. di Agronomia Ambientale e Produzioni Vegetali

    2000-06-01

    Since the interest on the use of wetlands to provide treatment of wastewaters is increasing in Italy, and the role of plants for the high performance of such systems is essential, observations on the ipogean part of Typha latifolia and Phragmites australis have been conducted after one year of growth in cubic containers (0,8 cm each side) filled with loamy textured soil. The length of rhizomes, the rhizomes and roots biomass production, and the TKN immobilisation in rhizomes and roots have been measured in soil layers of 10 cm wide. Typha latifolia and Phragmites australis produced high quantities of biomass (33 and 39 t {center_dot} ha{sup 1} of dry weight respectively) and showed a high immobilisation of nitrogen (270 and 250 kg {center_dot} ha{sup 1} respectively). The hypogeal part of Typha latifolia was developed especially in the first layers, whereas the one of Phragmites australis was more distributed along the soil profile (94 and 69% of the total biomass in the first 30 cm respectively). [Italian] Considerato l'interesse crescente che si sta osservando in Italia per la fitodepurazione delle acque inquinate e vista l'importanza che le piante esercitano in questa tecnologia, si sono condotte delle osservazioni sullo sviluppo dell'apparato ipogeo di Typha latifolia L. e Phragmites australis dopo un anno di accrescimento in cassoni cubici (0,8 m di lato) riempiti con terreno a grana media. Sono stati rilevati, per strati di 10 cm di profondita', la lunghezza dei rizomi, la biomassa di rizomi e radici ed il contenuto di TKN in rizomi e radici. Typha latifolia e Phragmites australis hanno prodotto molta biomassa (33 e 39 t {center_dot} ha{sup 1}di sostanza secca rispettivamente) ed hanno immagazinato una notevole quantita' di azoto (270 e 250 kg {center_dot} ha{sup 1} rispettivamente). Lungo il profilo del terreno, l'apparato ipogeo di Typha latifolia e' risultato piu' concentrato nei primi strati di quanto osservato in

  11. Pollinator specialization and pollination syndromes of three related North American Silene.

    Science.gov (United States)

    Reynolds, Richard J; Westbrook, M Jody; Rohde, Alexandra S; Cridland, Julie M; Fenster, Charles B; Dudash, Michele R

    2009-08-01

    Community and biogeographic surveys often conclude that plant-pollinator interactions are highly generalized. Thus, a central implication of the pollination syndrome concept, that floral trait evolution occurs primarily via specialized interactions of plants with their pollinators, has been questioned. However, broad surveys may not distinguish whether flower visitors are actual pollen vectors and hence lack power to assess the relationship between syndrome traits and the pollinators responsible for their evolution. Here we address whether the floral traits of three closely related hermaphroditic Silene spp. native to eastern North America (S. caroliniana, S. virginica, and S. stellata) correspond to predicted specialized pollination based on floral differences among the three species and the congruence of these floral features with recognized pollination syndromes. A nocturnal/diurnal pollinator exclusion experiment demonstrated that all three Silene spp. have diurnal pollinators, and only S. stellata has nocturnal pollinators. Multiyear studies of visitation rates demonstrated that large bees, hummingbirds, and nocturnal moths were the most frequent pollinators of S. caroliniana, S. virginica, and S. stellata, respectively. Estimates of pollen grains deposited and removed per visit generally corroborated the visitation rate results for all three species. However, the relatively infrequent diurnal hawkmoth pollinators of S. caroliniana were equally effective and more efficient than the most frequent large bee visitors. Pollinator importance (visitation X deposition) of each of the animal visitors to each species was estimated and demonstrated that in most years large bees and nocturnal moths were the most important pollinators of S. caroliniana and S. stellata, respectively. By quantifying comprehensive aspects of the pollination process we determined that S. virginica and S. stellata were specialized on hummingbirds and nocturnal moths, respectively, and S

  12. [Examples of the keeping of drugs during the XVIth, XVIIth and XVIIIth centuries: silenes and drawers].

    Science.gov (United States)

    Fievet, B

    1998-01-01

    Silenes are wooden boxes with colourful paintings for the keeping of drugs and can be found nowadays in three collections in France: Hotel-Dieu in Troyes (Aube), a pharmacy in Bauge (Maine-et-Loire) and St-Roch museum in Issoudun (Indre). Drawers can be related to silenes but they are more ordinary and less attractive.

  13. The genomics of plant sex chromosomes

    Czech Academy of Sciences Publication Activity Database

    Vyskot, Boris; Hobza, Roman

    2015-01-01

    Roč. 236, JUL 2015 (2015), s. 126-135 ISSN 0168-9452 R&D Projects: GA ČR(CZ) GBP501/12/G090; GA ČR(CZ) GAP501/12/2220 Institutional support: RVO:68081707 Keywords : Y-CHROMOSOME * SILENE-LATIFOLIA * DIOECIOUS PLANT Subject RIV: BO - Biophysics Impact factor: 3.362, year: 2015

  14. Fully automated pipeline for detection of sex linked genes using RNA-Seq data

    Czech Academy of Sciences Publication Activity Database

    Michalovová, Monika; Kubát, Zdeněk; Hobza, Roman; Vyskot, Boris; Kejnovský, Eduard

    2015-01-01

    Roč. 16, č. 78 (2015) ISSN 1471-2105 R&D Projects: GA ČR(CZ) GBP501/12/G090; GA MŠk(CZ) LM2010005 Institutional support: RVO:68081707 Keywords : SILENE-LATIFOLIA * RUMEX-ACETOSA * Y-CHROMOSOME Subject RIV: BO - Biophysics; EF - Botanics (UEB-Q) Impact factor: 2.435, year: 2015

  15. De novo transcriptome assembly of heavy metal tolerant Silene dioica

    Czech Academy of Sciences Publication Activity Database

    Čegan, R.; Hudzieczek, V.; Hobza, Roman

    2017-01-01

    Roč. 11, MAR (2017), s. 118-119 ISSN 2213-5960 Institutional support: RVO:61389030 Keywords : genome * Silene dioica * RNA-Seq * Transcriptome * Heavy metal tolerance * Sex chromosomes Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Plant sciences, botany

  16. Structural, functional, and evolutionary features of plant sex chromosomes

    Czech Academy of Sciences Publication Activity Database

    Vyskot, Boris; Hobza, Roman; Kejnovský, Eduard; Žlůvová, Jitka; Janoušek, Bohuslav

    2009-01-01

    Roč. 17, č. 4 (2009), s. 547 ISSN 0967-3849. [17th International Chromosome Conference. 23.06.2009-26.06.2009, Boone] R&D Projects: GA MŠk(CZ) LC06004 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : sex chromosomes * Silene latifolia * epigenetic Subject RIV: BO - Biophysics

  17. Satellite DNA and Transposable Elements in Seabuckthorn (Hippophae rhamnoides), a Dioecious Plant with Small Y and Large X Chromosomes

    Czech Academy of Sciences Publication Activity Database

    Puterova, Janka; Razumova, O.; Martínek, T.; Alexandrov, O.; Divashuk, M.; Kubát, Zdeněk; Hobza, Roman; Karlov, G.; Kejnovský, Eduard

    2017-01-01

    Roč. 9, č. 1 (2017), s. 197-212 ISSN 1759-6653 R&D Projects: GA ČR GBP501/12/G090 Grant - others:GA MŠk(CZ) LM2010005 Institutional support: RVO:68081707 Keywords : sex-chromosomes * repetitive sequences * silene-latifolia Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Developmental biology Impact factor: 3.979, year: 2016

  18. Oral administration of Gongronema latifolia leaf meal: Implications ...

    African Journals Online (AJOL)

    Jane

    2011-06-27

    Jun 27, 2011 ... 1Department of Animal Science, University of Nigeria, Nsukka. Enugu State ... supplement in poultry production. ... broiler feed, motivated this research. ... Fresh leaves of G. latifolia were harvested from a selected clone,.

  19. Impact of Repetitive Elements on the Y Chromosome Formation in Plants

    Czech Academy of Sciences Publication Activity Database

    Hobza, Roman; Čegan, Radim; Jesionek, Wojciech; Kejnovský, Eduard; Vyskot, Boris; Kubát, Zdeněk

    2017-01-01

    Roč. 8, č. 11 (2017), č. článku 302. ISSN 2073-4425 R&D Projects: GA ČR GA16-08698S; GA ČR GJ15-21523Y Institutional support: RVO:68081707 Keywords : papaya sex-chromosomes * male-specific region * transposable elements * silene-latifolia Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Developmental biology Impact factor: 3.600, year: 2016

  20. DRDC Ottawa Participation in the SILENE Accident Dosimetry Intercomparison Exercise. June 10-21, 2002

    National Research Council Canada - National Science Library

    Prud'homme-Lalonde, L

    2002-01-01

    .... The SILENE International Accident Dosimetry Intercomparison Exercise at Valduc, France in June 2002 coincided with DRDC Ottawa work designed to refine its proposed criticality dosimetry system...

  1. antimicrobial activities of methanolic extract of gongronema latifolia ...

    African Journals Online (AJOL)

    DJFLEX

    antimicrobial agents (Esimone et al., 2005). G. latifolia has been ... (Levine et al., 1993; Okeke et al., 2000; Oronsaye and. Oziegbe, 2002). .... availabilities of their chemical diversity (Abad et al.,. 2007). ... Akpan, P.A., 2004. Food from the ...

  2. Comparative high-throughput transcriptome sequencing and development of SiESTa, the Silene EST annotation database

    Directory of Open Access Journals (Sweden)

    Marais Gabriel AB

    2011-07-01

    Full Text Available Abstract Background The genus Silene is widely used as a model system for addressing ecological and evolutionary questions in plants, but advances in using the genus as a model system are impeded by the lack of available resources for studying its genome. Massively parallel sequencing cDNA has recently developed into an efficient method for characterizing the transcriptomes of non-model organisms, generating massive amounts of data that enable the study of multiple species in a comparative framework. The sequences generated provide an excellent resource for identifying expressed genes, characterizing functional variation and developing molecular markers, thereby laying the foundations for future studies on gene sequence and gene expression divergence. Here, we report the results of a comparative transcriptome sequencing study of eight individuals representing four Silene and one Dianthus species as outgroup. All sequences and annotations have been deposited in a newly developed and publicly available database called SiESTa, the Silene EST annotation database. Results A total of 1,041,122 EST reads were generated in two runs on a Roche GS-FLX 454 pyrosequencing platform. EST reads were analyzed separately for all eight individuals sequenced and were assembled into contigs using TGICL. These were annotated with results from BLASTX searches and Gene Ontology (GO terms, and thousands of single-nucleotide polymorphisms (SNPs were characterized. Unassembled reads were kept as singletons and together with the contigs contributed to the unigenes characterized in each individual. The high quality of unigenes is evidenced by the proportion (49% that have significant hits in similarity searches with the A. thaliana proteome. The SiESTa database is accessible at http://www.siesta.ethz.ch. Conclusion The sequence collections established in the present study provide an important genomic resource for four Silene and one Dianthus species and will help to

  3. Comparative high-throughput transcriptome sequencing and development of SiESTa, the Silene EST annotation database

    Science.gov (United States)

    2011-01-01

    Background The genus Silene is widely used as a model system for addressing ecological and evolutionary questions in plants, but advances in using the genus as a model system are impeded by the lack of available resources for studying its genome. Massively parallel sequencing cDNA has recently developed into an efficient method for characterizing the transcriptomes of non-model organisms, generating massive amounts of data that enable the study of multiple species in a comparative framework. The sequences generated provide an excellent resource for identifying expressed genes, characterizing functional variation and developing molecular markers, thereby laying the foundations for future studies on gene sequence and gene expression divergence. Here, we report the results of a comparative transcriptome sequencing study of eight individuals representing four Silene and one Dianthus species as outgroup. All sequences and annotations have been deposited in a newly developed and publicly available database called SiESTa, the Silene EST annotation database. Results A total of 1,041,122 EST reads were generated in two runs on a Roche GS-FLX 454 pyrosequencing platform. EST reads were analyzed separately for all eight individuals sequenced and were assembled into contigs using TGICL. These were annotated with results from BLASTX searches and Gene Ontology (GO) terms, and thousands of single-nucleotide polymorphisms (SNPs) were characterized. Unassembled reads were kept as singletons and together with the contigs contributed to the unigenes characterized in each individual. The high quality of unigenes is evidenced by the proportion (49%) that have significant hits in similarity searches with the A. thaliana proteome. The SiESTa database is accessible at http://www.siesta.ethz.ch. Conclusion The sequence collections established in the present study provide an important genomic resource for four Silene and one Dianthus species and will help to further develop Silene as a

  4. Leaf gas exchange and fluorescence of Phillyrea latifolia, Pistacia lentiscus and Quercus ilex saplings in severe drought and high temperature conditions

    International Nuclear Information System (INIS)

    Filella, I.; Llusià, J.; Pinol, J.; Peñuelas, J.

    1998-01-01

    Saplings of Phillyrea latifolia, Pistacia lentiscus and Quercus ilex were withheld watering for 7 days, followed by reirrigation. Incident photosynthetic photon flux density (PPFD), leaf temperature, net photosynthetic rates, stomatal conductance, and photochemical efficiency of the photosystem II (ΔF/F'm) were measured three times during the day. The watered plants had higher photosynthetic rates, stomatal conductances, ΔF/F'm and ETR than non-watered plants. However, watered plants were mildly water stressed as shown by low ratio of variable to maximal fluorescence (Fv/Fm) and high non-photochemical fluorescence quenching (qN). Their ΔF/F′m was low in the morning and increased in the evening, following the variations in PPFD. Watered plants of Q. ilex had lower photosynthetic activity, stomatal conductance and photosynthetic radiation use efficiency than Ph. latifolia and P. lentiscus, and, conversely, reached the highest ΔF/F′m and ETR. This seems to indicate a different relationship between photosynthetic activity and electron transport rate in Q. ilex compared to the other two species. Ph. latifolia and P. lentiscus appeared to be better adapted to severe drought than Q. ilex. (author)

  5. Analytical evaluation of dose measurement of critical accident at SILENE (Contract research)

    CERN Document Server

    Nakamura, T; Tonoike, K

    2003-01-01

    Institute for Radioprotection and Nuclear Safety (IRSN) and the OECD Nuclear Energy Agency (NEA) jointly organized SILENE Accident Dosimetry Intercomparison Exercise to intercompare the dose measurement systems of participating countries. Each participating country carried out dose measurements in the same irradiation field, and the measurement results were mutually compared. The participated in the exercise to measure the doses of gamma rays and neutron from SILENE by using thermoluminescence dosimeters (TLD's) and an alanine dosimeter. In this examination, the derived evaluation formulae for obtaining a tissue-absorbed dose from measured value (ambient dose equivalent) of TLD for neutron. We reported the tissue-absorbed dose computed using this evaluation formula to OECD/NEA. TLD's for neutron were irradiated in the TRACY facility to verify the evaluation formulae. The results of TLD's were compared with the calculations of MCNP and measurements with alanine dose meter. We found that the ratio of the dose b...

  6. Detailed adsorption mechanism of plasmid DNA by newly isolated cellulose from waste flower spikes of Thypa latifolia using quantum chemical calculations.

    Science.gov (United States)

    Mujtaba, Muhammad; Kaya, Murat; Akyuz, Lalehan; Erdonmez, Demet; Akyuz, Bahar; Sargin, Idris

    2017-09-01

    Current study was designed to use the newly obtained cellulose from waste flower spikes of Thypa latifolia plant for plasmid DNA adsorption. Cellulose was isolated according to a previously described method including acid and base treatment, and cellulose content was recorded as 17%. T. latifolia cellulose was physicochemically characterized via FT-IR, TGA and SEM techniques. Detailed mechanism of plasmid DNA adsorption by newly isolated cellulose was described using chemical quantum calculations. To check the effect of Cu ++ immobilization on the affinity of cellulose for plasmid DNA, copper ions were immobilized onto T. latifolia cellulose. pUC18 plasmid DNA was used for adsorption studies. Membranes prepared with only T. latifolia cellulose and Cu ++ immobilized T. latifolia cellulose revealed different adsorption ratios as 43.9 and 86.9% respectively. This newly isolated cellulose from waste flower spikes of T. latifolia can be utilized as a suitable carrier for plasmid DNA. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Analgesic compounds from Scorzonera latifolia (Fisch. and Mey.) DC

    Czech Academy of Sciences Publication Activity Database

    Bahadir, Ö.; Citoglu, G. S.; Šmejkal, K.; Dall Acqua, S.; Özbek, H.; Cvačka, Josef; Žemlička, M.

    2010-01-01

    Roč. 131, č. 1 (2010), s. 83-87 ISSN 0378-8741 Institutional research plan: CEZ:AV0Z40550506 Keywords : Scorzonera latifolia * analgesic activity * triterpenes Subject RIV: CC - Organic Chemistry Impact factor: 2.466, year: 2010

  8. A Comparison of Selective Pressures in Plant X-Linked and Autosomal Genes.

    Science.gov (United States)

    Krasovec, Marc; Nevado, Bruno; Filatov, Dmitry A

    2018-05-03

    Selection is expected to work differently in autosomal and X-linked genes because of their ploidy difference and the exposure of recessive X-linked mutations to haploid selection in males. However, it is not clear whether these expectations apply to recently evolved sex chromosomes, where many genes retain functional X- and Y-linked gametologs. We took advantage of the recently evolved sex chromosomes in the plant Silene latifolia and its closely related species to compare the selective pressures between hemizygous and non-hemizygous X-linked genes as well as between X-linked genes and autosomal genes. Our analysis, based on over 1000 genes, demonstrated that, similar to animals, X-linked genes in Silene evolve significantly faster than autosomal genes—the so-called faster-X effect. Contrary to expectations, faster-X divergence was detectable only for non-hemizygous X-linked genes. Our phylogeny-based analyses of selection revealed no evidence for faster adaptation in X-linked genes compared to autosomal genes. On the other hand, partial relaxation of purifying selection was apparent on the X-chromosome compared to the autosomes, consistent with a smaller genetic diversity in S. latifolia X-linked genes (π x = 0.016; π aut = 0.023). Thus, the faster-X divergence in S. latifolia appears to be a consequence of the smaller effective population size rather than of a faster adaptive evolution on the X-chromosome. We argue that this may be a general feature of “young” sex chromosomes, where the majority of X-linked genes are not hemizygous, preventing haploid selection in heterogametic sex.

  9. Satellite DNA and Transposable Elements in Seabuckthorn (Hippophae rhamnoides), a Dioecious Plant with Small Y and Large X Chromosomes

    Czech Academy of Sciences Publication Activity Database

    Puterová, J.; Razumova, O.; Martínek, T.; Alexandrov, O.; Divashuk, M.; Kubát, Z.; Hobza, Roman; Karlov, G.; Kejnovský, E.

    2017-01-01

    Roč. 9, č. 1 (2017), s. 197-212 ISSN 1759-6653 R&D Projects: GA ČR GBP501/12/G090 Institutional support: RVO:61389030 Keywords : sex-chromosomes * repetitive sequences * silene-latifolia * molecular cytogenetics * arabidopsis-thaliana * genome size * evolution * organization * alignment * database * sex chromosomes * genome composition * chromosomal localization * repetitive DNA Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Plant sciences, botany Impact factor: 3.979, year: 2016

  10. Constructive applications of composite gypsum reinforced with Typha Latifolia fibres

    Directory of Open Access Journals (Sweden)

    Garcia Santos, A.

    2004-03-01

    Full Text Available The present research analyses the possibility to reinforce gypsum using enea fibres (Typha Latifolia creating a compound material in wich the fibres contribute to increase mechanical resistance, producing as well a reduction of the weight and a possible regulation of the set time.

    La investigación presente analiza la posibilidad de reforzar los morteros de escayola mediante la utilización dé fibras de Typha Latifolia, creando un material compuesto en el que las fibras contribuyen al aumento de resistencia mecánica, a la vez que se produce una reducción del peso y una regulación de los tiempos de fraguado. Las propiedades de estos materiales hacen que, en determinadas aplicaciones, su utilización resulte ventajosa con respecto a materiales tradicionales.

  11. 2010 Criticality Accident Alarm System Benchmark Experiments At The CEA Valduc SILENE Facility

    International Nuclear Information System (INIS)

    Miller, Thomas Martin; Dunn, Michael E.; Wagner, John C.; McMahan, Kimberly L.; Authier, Nicolas; Jacquet, Xavier; Rousseau, Guillaume; Wolff, Herve; Piot, Jerome; Savanier, Laurence; Baclet, Nathalie; Lee, Yi-kang; Masse, Veronique; Trama, Jean-Christophe; Gagnier, Emmanuel; Naury, Sylvie; Lenain, Richard; Hunter, Richard; Kim, Soon; Dulik, George Michael; Reynolds, Kevin H.

    2011-01-01

    Several experiments were performed at the CEA Valduc SILENE reactor facility, which are intended to be published as evaluated benchmark experiments in the ICSBEP Handbook. These evaluated benchmarks will be useful for the verification and validation of radiation transport codes and evaluated nuclear data, particularly those that are used in the analysis of CAASs. During these experiments SILENE was operated in pulsed mode in order to be representative of a criticality accident, which is rare among shielding benchmarks. Measurements of the neutron flux were made with neutron activation foils and measurements of photon doses were made with TLDs. Also unique to these experiments was the presence of several detectors used in actual CAASs, which allowed for the observation of their behavior during an actual critical pulse. This paper presents the preliminary measurement data currently available from these experiments. Also presented are comparisons of preliminary computational results with Scale and TRIPOLI-4 to the preliminary measurement data.

  12. Arsenate tolerance in Silene paradoxa does not rely on phytochelatin-dependent sequestration

    International Nuclear Information System (INIS)

    Arnetoli, Miluscia; Vooijs, Riet; Bookum, Wilma ten; Galardi, Francesca; Gonnelli, Cristina; Gabbrielli, Roberto; Schat, Henk; Verkleij, Jos A.C.

    2008-01-01

    Arsenate tolerance, As accumulation and As-induced phytochelatin accumulation were compared in populations of Silene paradoxa, one from a mine site enriched in As, Cu and Zn, the other from an uncontaminated site. The mine population was significantly more arsenate-tolerant. Arsenate uptake and root-to-shoot transport were slightly but significantly higher in the non-mine plants. The difference in uptake was quantitatively insufficient to explain the difference in tolerance between the populations. As accumulation in the roots was similar in both populations, but the mine plants accumulated much less phytochelatins than the non-mine plants. The mean phytochelatin chain length, however, was higher in the mine population, possibly due to a constitutively lower cellular glutathione level. It is argued that the mine plants must possess an arsenic detoxification mechanism other than arsenate reduction and subsequent phytochelatin-based sequestration. This alternative mechanism might explain at least some part of the superior tolerance in the mine plants. - Neither decreased uptake nor phytochelatins seem to play a role in the As tolerance in Silene paradoxa

  13. Dalbergia latifolia Roxb. (East Indian Rosewood) of Leguminosae is ...

    Indian Academy of Sciences (India)

    Dalbergia latifolia Roxb. (East Indian Rosewood) of Leguminosae is a large deciduous or nearly evergreen tree that grows in mixed deciduous forests with teak. Leaves are compound. The creamy white flowers are borne on branched inflorescences. The indehiscent dry pod bears. 1-4 seeds. Inset - a juvenile plant.

  14. The SILENE reactor: an instrument suitable for studying the impact of intermediate and high radiation doses

    International Nuclear Information System (INIS)

    Verray, B.; Leo, Y.; Fouillaud, P.

    2002-01-01

    Designed in 1974 to study the phenomenology and consequences of a criticality accident, the SILENE experimental reactor, an intense source of mixed neutron and gamma radiation, is also suited to radiobiological studies. (author)

  15. Comparative mapping of the wild perennial Glycine latifolia and soybean (G. max reveals extensive chromosome rearrangements in the genus Glycine.

    Directory of Open Access Journals (Sweden)

    Sungyul Chang

    Full Text Available Soybean (Glycine max L. Mer., like many cultivated crops, has a relatively narrow genetic base and lacks diversity for some economically important traits. Glycine latifolia (Benth. Newell & Hymowitz, one of the 26 perennial wild Glycine species related to soybean in the subgenus Glycine Willd., shows high levels of resistance to multiple soybean pathogens and pests including Alfalfa mosaic virus, Heterodera glycines Ichinohe and Sclerotinia sclerotiorum (Lib. de Bary. However, limited information is available on the genomes of these perennial Glycine species. To generate molecular resources for gene mapping and identification, high-density linkage maps were constructed for G. latifolia using single nucleotide polymorphism (SNP markers generated by genotyping by sequencing and evaluated in an F2 population and confirmed in an F5 population. In each population, greater than 2,300 SNP markers were selected for analysis and segregated to form 20 large linkage groups. Marker orders were similar in the F2 and F5 populations. The relationships between G. latifolia linkage groups and G. max and common bean (Phaseolus vulgaris L. chromosomes were examined by aligning SNP-containing sequences from G. latifolia to the genome sequences of G. max and P. vulgaris. Twelve of the 20 G. latifolia linkage groups were nearly collinear with G. max chromosomes. The remaining eight G. latifolia linkage groups appeared to be products of multiple interchromosomal translocations relative to G. max. Large syntenic blocks also were observed between G. latifolia and P. vulgaris. These experiments are the first to compare genome organizations among annual and perennial Glycine species and common bean. The development of molecular resources for species closely related to G. max provides information into the evolution of genomes within the genus Glycine and tools to identify genes within perennial wild relatives of cultivated soybean that could be beneficial to soybean

  16. Non-coding RNA may be associated with cytoplasmic male sterility in Silene vulgaris

    Czech Academy of Sciences Publication Activity Database

    Stone, James D.; Koloušková, Pavla; Sloan, D.B.; Štorchová, Helena

    2017-01-01

    Roč. 68, č. 7 (2017), s. 1599-1612 ISSN 0022-0957 R&D Projects: GA ČR(CZ) GA16-09220S Institutional support: RVO:61389030 Keywords : Cytoplasmic male sterility * Editing * Mitochondrion * Non-coding RNA * Silene vulgaris * Splicing * Transcriptome Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 5.830, year: 2016

  17. SILENE and TDT: A code for collision probability calculations in XY geometries

    International Nuclear Information System (INIS)

    Sanchez, R.; Stankovski, Z.

    1993-01-01

    Collision probability methods are routinely used for cell and assembly multigroup transport calculations in core design tasks. Collision probability methods use a specialized tracking routine to compute neutron trajectories within a given geometric object. These trajectories are then used to generate the appropriate collision matrices in as many groups as required. Traditional tracking routines are based on open-quotes globalclose quotes geometric descriptions (such as regular meshes) and are not able to cope with the geometric detail required in actual core calculations. Therefore, users have to modify their geometry in order to match the geometric model accepted by the tracking routine, introducing thus a modeling error whose evaluation requires the use of a open-quotes referenceclose quotes method. Recently, an effort has been made to develop more flexible tracking routines either by directly adopting tracking Monte Carlo techniques or by coding of complicated geometries. Among these, the SILENE and TDT package is being developed at the Commissariat a l' Energie Atomique to provide routine as well as reference calculations in arbitrarily shaped XY geometries. This package combines a direct graphical acquisition system (SILENE) together with a node-based collision probability code for XY geometries (TDT)

  18. Analytical evaluation of dose measurement of critical accident at SILENE (Contract research)

    Energy Technology Data Exchange (ETDEWEB)

    Nakamura, Takemi; Tonoike, Kotaro; Miyoshi, Yoshinori [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2003-03-01

    Institute for Radioprotection and Nuclear Safety (IRSN) and the OECD Nuclear Energy Agency (NEA) jointly organized SILENE Accident Dosimetry Intercomparison Exercise to intercompare the dose measurement systems of participating countries. Each participating country carried out dose measurements in the same irradiation field, and the measurement results were mutually compared. The authors participated in the exercise to measure the doses of gamma rays and neutron from SILENE by using thermoluminescence dosimeters (TLD's) and an alanine dosimeter. In this examination, the authors derived evaluation formulae for obtaining a tissue-absorbed dose from measured value (ambient dose equivalent) of TLD for neutron. We reported the tissue-absorbed dose computed using this evaluation formula to OECD/NEA. TLD's for neutron were irradiated in the TRACY facility to verify the evaluation formulae. The results of TLD's were compared with the calculations of MCNP and measurements with alanine dose meter. We found that the ratio of the dose by the evaluation formula to the measured value by the alanine dosimeter was 0.94 and the formula agreed within 6%. From examination of this TRACY, we can conclude that the value reported to OECD/NEA has equivalent accuracy. (author)

  19. Isolation and characterization of microsatellite markers and analysis of genetic variability in Curculigo latifolia Dryand.

    Science.gov (United States)

    Babaei, Nahid; Abdullah, Nur Ashikin Psyquay; Saleh, Ghizan; Abdullah, Thohirah Lee

    2012-11-01

    Curculin, a sweet protein found in Curculigo latifolia fruit has great potential for the pharmaceutical industry. This protein interestingly has been found to have both sweet taste and taste-modifying capacities comparable with other natural sweeteners. According to our knowledge this is the first reported case on the isolation of microsatellite loci in this genus. Hence, the current development of microsatellite markers for C. latifolia will facilitate future population genetic studies and breeding programs for this valuable plant. In this study 11 microsatellite markers were developed using 3' and 5' ISSR markers. The primers were tested on 27 accessions from all states of Peninsular Malaysia. The number of alleles per locus ranged from three to seven, with allele size ranging from 141 to 306 bp. The observed and expected heterozygosity ranged between 0.00-0.65 and 0.38-0.79, respectively. The polymorphic information content ranged from 0.35 to 0.74 and the Shannon's information index ranged from 0.82 to 1.57. These developed polymorphic microsatellites were used for constructing a dendrogram by unweighted pair group method with arithmetic mean cluster analysis using the Dice's similarity coefficient. Accessions association according to their geographical origin was observed. Based on characteristics of isolated microsatellites for C. latifolia accessions all genotype can be distinguished using these 11 microsatellite markers. These polymorphic markers could also be applied to studies on uniformity determination and somaclonal variation of tissue culture plantlets, varieties identification, genetic diversity, analysis of phylogenetic relationship, genetic linkage maps and quantitative trait loci in C. latifolia.

  20. TRIPOLI calculation of the neutron field in the hall of the SILENE reactor

    International Nuclear Information System (INIS)

    Bourdet, L.

    1986-05-01

    This study concerns the utilization of the experimental reactor SILENE as radiation source. Its aim is to get a theoretical estimation of the neutron field characteristics in different points of the irradiation hall (spectra, fluences, equivalents of biological doses and reaction yields). These estimations are compared to results obtained by several experimental techniques; they allow to know better this neutron field with or without lead shield [fr

  1. Bioactive screening and in vitro antioxidant assessment of Nauclea latifolia leaf decoction

    Science.gov (United States)

    Iheagwam, Franklyn Nonso; Nsedu, Emmanuel Israel; Kayode, Kazeem Oyindamola; Emiloju, Opeyemi Christianah; Ogunlana, Olubanke Olujoke; Chinedu, Shalom Nwodo

    2018-04-01

    The phytochemical constituents and antioxidant properties of Nauclea latifolia leaf decoction were investigated. Dried leaves were extracted in ethanol. Qualitative and quantitative phytochemical analysis was determined spectrometrically. The antioxidant activities were examined in vitro using 2,2-diphenyl-1-picrylhydrazyl radical, total antioxidant capacity and ferric reducing antioxidant power assays. Phytochemical screening confirmed the presence of flavonoids, alkaloids, anthocyanins, betacyanins, phenols, saponins, terpenoids, cardiac glycosides and quinones. The total lycopene, β-carotene, phenolics, flavonoid and alkaloid content were found to be 0.038 ± 0.01 mg CAE/g, 0.120 ± 0.04 mg CAE/g, 58.08 ± 0.58 mg GAE/g, 10.75 ± 0.17 mg RE/g and 0.32 ± 0.08% respectively. N. latifolia ethanol leaf extract demonstrated effective antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl with an IC50 of 2.58 ± 0.08 mg/mL compared to 0.86 ± 0.02 mg/mL and < 0.01 ± 0.01 mg/mL for butylated hydroxytoluene and ascorbic acid respectively. Total antioxidant capacity and ferric reducing antioxidant power of the extract were 73.81 ± 2.27 and 1314.45 ± 197.64 mg AAE/g respectively. Excellent positive correlations between the phenolic content and antioxidant activities of the extract were observed. The leaf of N. latifolia is of therapeutic value and may be exploited for its rich antioxidant components.

  2. Potential of a polyculture of Arundo donax and Typha latifolia for ...

    African Journals Online (AJOL)

    Arundo donax and Typha latifolia are emergent macrophyte species that commonly reproduce in humid areas during warm months. This study investigated the growth and pollutant removal capacity of these two species planted in polyculture in a vertical flow filter bed for rural wastewater treatment. Plant shoot height was ...

  3. High Pb concentration stress on Typha latifolia growth and Pb removal in microcosm wetlands.

    Science.gov (United States)

    Han, Jianqiu; Chen, Fengzhen; Zhou, Yumei; Wang, Chaohua

    2015-01-01

    When constructed wetlands are used to treat high-Pb wastewater, Pb may become a stress to wetland plants, which subsequently reduces treatment performance and the other ecosystem services. To facilitate the design and operation of constructed wetlands for treatment of Pb-rich wastewater, we investigated the irreversible inhibitory level of Pb for Typha latifolia through experiments in microcosm wetlands. Seven horizontal subsurface flow constructed wetlands were built with rectangular plastic tanks and packed with marble chips and sand. All wetlands were transplanted with nine stems of Typha latifolia each. The wetlands were batch operated in a greenhouse with artificial wastewater (10 L each) for 12 days. Influent to the seven wetlands had different concentrations of Pb: 0 mg/L, 10 mg/L, 25 mg/L, 50 mg/L, 100 mg/L, 200 mg/L, and 500 mg/L, respectively. The results suggested that leaf chlorophyll relative content, relative growth rate, photosynthetic characteristics, activities of superoxide dismutase, peroxidase, and content of malondialdehyde were not affected when initial Pb concentration was at 100 mg/L and below. But when initial Pb concentration was above 100 mg/L, all of them were seriously affected. We conclude that high Pb concentrations wastewater could inhibit the growth of Typha latifolia and decrease the removal rate of wetlands.

  4. Biological control of golden apple snail, Pomacea canaliculata by Chinese soft-shelled turtle, Pelodiscus sinensis in the wild rice, Zizania latifolia field

    Directory of Open Access Journals (Sweden)

    Shengzhang Dong

    2012-04-01

    Full Text Available The wild rice, Zizania latifolia Turcz, used to be one of the important aquatic vegetables cultivated in China. Recently, the golden apple snail - GAS (Pomacea canaliculata (Lamarck was found to be a major invasive pest attacking Z. latifolia. To control efficiently GAS, predation by the Chinese soft-shelled turtles (Pelodiscus sinensis on GAS was evaluated in laboratory and field trials. P. sinensis had a strong predatory capacity and selectivity for GAS both in laboratory and field conditions. All the sizes of P. sinensis prefer to capture smaller snails. The optimum number of P. sinensis released in Z. latifolia field was dependent on the density of over-wintered GAS, and varied between 30 and 50 turtles per 666.7 m². The number of GAS declined in the fields with turtles as compared to turtle-free field. A pattern of releasing P. sinensis in Z. latifolia fields was developed and widely adopted by farmers because of much more benefit besides biologically controlling GAS.

  5. Effect of aspect on distribution pattern of Anogeissus latifolia (Wall ...

    African Journals Online (AJOL)

    This paper reports on effect of aspect on distribution pattern of Anogeissus latifolia is an important fuel, fodder and timber species of sub-tropical belt of Garhwal Himalaya. The study was carried out in two aspects i.e., south-east (SE) aspect and south-west (SW) aspect in sub-tropical region (300 29' N and 780 24' E) of ...

  6. Criticality accident dosimetry systems: an international intercomparison at the SILENE reactor in 2002.

    Science.gov (United States)

    Médioni, R; Asselineau, B; Verrey, B; Trompier, F; Itié, C; Texier, C; Muller, H; Pelcot, G; Clairand, I; Jacquet, X; Pochat, J L

    2004-01-01

    In criticality accident dosimetry and more generally for high dose measurements, special techniques are used to measure separately the gamma ray and neutron components of the dose. To improve these techniques and to check their dosimetry systems (physical and/or biological), a total of 60 laboratories from 29 countries (America, Europe, Asia) participated in an international intercomparaison, which took place in France from 9 to 21 June 2002, at the SILENE reactor in Valduc and at a pure gamma source in Fontenay-aux-Roses. This intercomparison was jointly organised by the IRSN and the CEA with the help of the NEA/OCDE and was partly supported by the European Communities. This paper describes the aim of this intercomparison, the techniques used by the participants and the two radiation sources and their characteristics. The experimental arrangements of the dosemeters for the irradiations in free air or on phantoms are given. Then the dosimetric quantities measured and reported by the participants are summarised, analysed and compared with the reference values. The present paper concerns only the physical dosimetry and essentially experiments performed on the SILENE facility. The results obtained with the biological dosimetry are published in two other papers of this issue.

  7. Measurement of the gamma field around Silene reactor

    International Nuclear Information System (INIS)

    Spurny, Frantisek; Medioni, Roger.

    1976-07-01

    A method for measuring the gamma component in the mixed field emitted by the Silene facility implanted in Valduc is investigated. Various thermoluminescent phosphors (natural LiF, 7 LiF, SO 4 Ca, Al 2 O 3 ) in containers of different sizes and types are used. The detectors results are corrected for their neutron sensitivity by using coefficients which were determined in previous studies. Alumina is shown to be the most suitable detector for this problem because of the dose ranges to be measured and its low sensitivity to neutrons. A series of measurements carried out at many points in the irradiation hall shows a good homogeneity in the gamma distribution. Results are given for different distances from the source and for a 10 17 fissions power of the reactor [fr

  8. Lavandula angustifolia and Lavandula latifolia Essential Oils from Spain: Aromatic Profile and Bioactivities.

    Science.gov (United States)

    Carrasco, Alejandro; Martinez-Gutierrez, Ramiro; Tomas, Virginia; Tudela, Jose

    2016-01-01

    Compositions of true lavender (Lavandula angustifolia) and spike lavender (Lavandula latifolia) essential oils, cultivated and extracted in the Southeast of Spain, were determined by gas chromatography coupled with mass spectrometry detection, obtaining both relative (peak area) and absolute (using standard curves) concentrations. Linalool (37-54 %), linalyl acetate (21-36 %) and (E)-β-caryophyllene (1-3 %) were the most abundant components for L. angustifolia. Linalool (35-51 %), eucalyptol (26-32 %), camphor (10-18 %), α-pinene (1-2 %), α-terpineol (1-2 %) and α-bisabolene (1-2 %) were the most abundant components for L. latifolia. The characterization was completed with enantioselective gas chromatography, in which the determined main molecules were (-)-linalool, (-)-linalyl acetate and (+)-camphor. (S)-(-)-camphene, (R)-(+)-limonene, (1R, 9S)-(-)-(E)-β-caryophyllene and (1R, 4R, 6R, 10S)-(-)-caryophyllene oxide were found in this study as the predominant enantiomers in Spanish L. angustifolia. The characterised essential oils were tested for their antioxidant activity against free radicals ABTS, DPPH, ORAC, chelating, and reducing power. Inhibitory activity on lipoxygenase was observed indicating a possible anti-inflammatory activity, mainly due to linalool, camphor, p-cymene and limonene. These results can be the starting point for a future study of the potential use of L. angustifolia and L. latifolia essential oils as natural cosmetic and natural pharmaceutical ingredients for several skin diseases. Georg Thieme Verlag KG Stuttgart · New York.

  9. Antidiabetic and Hypolipidemic Activities of Curculigo latifolia Fruit:Root Extract in High Fat Fed Diet and Low Dose STZ Induced Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Nur Akmal Ishak

    2013-01-01

    Full Text Available Curculigo latifolia fruit is used as alternative sweetener while root is used as alternative treatment for diuretic and urinary problems. The antidiabetic and hypolipidemic activities of C. latifolia fruit:root aqueous extract in high fat diet (HFD and 40 mg streptozotocin (STZ induced diabetic rats through expression of genes involved in glucose and lipid metabolisms were investigated. Diabetic rats were treated with C. latifolia fruit:root extract for 4 weeks. Plasma glucose, insulin, adiponectin, lipid profiles, alanine aminotransferase (ALT, gamma glutamyltransferase (GGT, urea, and creatinine levels were measured before and after treatments. Regulations of selected genes involved in glucose and lipid metabolisms were determined. Results showed the significant (P<0.05 increase in body weight, high density lipoprotein (HDL, insulin, and adiponectin levels and decreased glucose, total cholesterol (TC, triglycerides (TG, low density lipoprotein (LDL, urea, creatinine, ALT, and GGT levels in diabetic rats after 4 weeks treatment. Furthermore, C. latifolia fruit:root extract significantly increased the expression of IRS-1, IGF-1, GLUT4, PPARα, PPARγ, AdipoR1, AdipoR2, leptin, LPL, and lipase genes in adipose and muscle tissues in diabetic rats. These results suggest that C. latifolia fruit:root extract exerts antidiabetic and hypolipidemic effects through altering regulation genes in glucose and lipid metabolisms in diabetic rats.

  10. Studies on the chemical constituents of the fruits of Cordia latifolia.

    Science.gov (United States)

    Siddiqui, Bina S; Perwaiz, Sobiya; Begum, Sabira

    2006-02-01

    Four new aromatic compounds have been isolated from the fruits of Cordia latifolia (Boreginaceae) bearing a common basic skeleton but differing in the side chain. Their structures were elucidated using spectrometric methods including 1D- (1H and 13C) and 2D-NMR experiments, (1H, 1H-COSY, NOESY, HMQC and HMBC) and chemical transformations.

  11. Contrasting Patterns of Transposable Element and Satellite Distribution on Sex Chromosomes (XY1Y2) in the Dioecious Plant Rumex acetosa

    Czech Academy of Sciences Publication Activity Database

    Šteflová, Pavlína; Tokan, Viktor; Vogel, Ivan; Lexa, M.; Macas, Jiří; Novák, Petr; Hobza, Roman; Vyskot, Boris; Kejnovský, Eduard

    2013-01-01

    Roč. 5, č. 4 (2013), s. 769-782 ISSN 1759-6653 R&D Projects: GA ČR(CZ) GAP305/10/0930; GA ČR(CZ) GAP501/10/0102; GA ČR(CZ) GAP501/12/2220 Grant - others:GA MŠk(CZ) ED1.1.00/02.0068 Program:ED Institutional research plan: CEZ:AV0Z50040702 Institutional support: RVO:68081707 ; RVO:60077344 Keywords : Y-CHROMOSOME * REPETITIVE SEQUENCES * SILENE-LATIFOLIA Subject RIV: BO - Biophysics; EB - Genetics ; Molecular Biology (BC-A) Impact factor: 4.532, year: 2013

  12. Studies on the terpene metabolism in Lavandula latifolia Medicus

    OpenAIRE

    Mendoza Poudereux, Isabel

    2013-01-01

    Resumen en castellano Estudio del metabolismo de los terpenos en Lavandula latifolia Medicus Justificación y objetivos La biosíntesis de los dos precursores universales de los terpenos vegetales, el isopentenildifosfato (IPP) y el dimetilalildifosfato (DMAPP), es un proceso complejo en el que intervienen dos rutas metabólicas independientes (Rodríguez-Concepción y Boronat, 2002; Lange y Ahkami, 2013): La ruta del mevalonato (MVA) que opera en el citosol, retículo endoplasmático y ...

  13. Typha angustifolia L. X T. latifolia L. (T.) (glauca Godr.) in Nederland

    NARCIS (Netherlands)

    Ooststroom, van S.J.; Reichgelt, Th.J.

    1962-01-01

    Typha x glauca Godr., the hybrid of T. angustifolia L. and T. latifolia L. was found in the Netherlands for the first time in 1847 and again in 1946, as appears from the collections in the Rijksherbarium, Leiden. Fig. 1 shows the differences found in the female flowers, the pollen, and the

  14. Two Silene vulgaris copper transporters residing in different cellular compartments confer copper hypertolerance by distinct mechanisms when expressed in Arabidopsis thaliana.

    Science.gov (United States)

    Li, Yanbang; Iqbal, Mazhar; Zhang, Qianqian; Spelt, Cornelis; Bliek, Mattijs; Hakvoort, Henk W J; Quattrocchio, Francesca M; Koes, Ronald; Schat, Henk

    2017-08-01

    Silene vulgaris is a metallophyte of calamine, cupriferous and serpentine soils all over Europe. Its metallicolous populations are hypertolerant to zinc (Zn), cadmium (Cd), copper (Cu) or nickel (Ni), compared with conspecific nonmetallicolous populations. These hypertolerances are metal-specific, but the underlying mechanisms are poorly understood. We investigated the role of HMA5 copper transporters in Cu-hypertolerance of a S. vulgaris copper mine population. Cu-hypertolerance in Silene is correlated and genetically linked with enhanced expression of two HMA5 paralogs, SvHMA5I and SvHMA5II, each of which increases Cu tolerance when expressed in Arabidopsis thaliana. Most Spermatophytes, except Brassicaceae, possess homologs of SvHMA5I and SvHMA5II, which originate from an ancient duplication predating the appearance of spermatophytes. SvHMA5II and the A. thaliana homolog AtHMA5 localize in the endoplasmic reticulum and upon Cu exposure move to the plasma membrane, from where they are internalized and degraded in the vacuole. This resembles trafficking of mammalian homologs and is apparently an extremely ancient mechanism. SvHMA5I, instead, neofunctionalized and always resides on the tonoplast, likely sequestering Cu in the vacuole. Adaption of Silene to a Cu-polluted soil is at least in part due to upregulation of two distinct HMA5 transporters, which contribute to Cu hypertolerance by distinct mechanisms. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  15. Analysis of Chromosome Number in Some Allium and Silene Wild Species with Ornamental Use

    OpenAIRE

    Lucia DRAGHIA; Elena Liliana CHELARIU; Culiţă SÎRBU; Maria BRÂNZĂ; Cristina SANDU MICULSCHI

    2013-01-01

    The present study analyses the number of somatic chromosomes in plant species with ornamental value, in Romanian indigenous flora, Allium (A. flavum L., A. saxatile Bieb.) and Silene (S. compacta Fischer., S. supina M.Bieb.). The biological material was identified and harvested in the South-Eastern part of Dobrogea (Tulcea and Constanţa counties), area in the South-Eastern part of Romania, situated between the Danube and the Black Sea. Individuals from two populations of Allium flavum and All...

  16. A new anthraquinone and a new naphthoquinone from the whole plant of Spermacoce latifolia.

    Science.gov (United States)

    Luo, Ying; Shen, Hai-Yan; Shen, Qing-Xiang; Cao, Zhao-Hui; Zhang, Min; Long, Shi-Yin; Wang, Zong-Bao; Tan, Jian-Wen

    2017-09-01

    A phytochemical study on the whole plant of Spermacoce latifolia led to the isolation of a new anthraquinone, 1,2,6-trihydroxy-5-methoxy-9,10-anthraquinone (1), and a new naphthoquinone, (2R)-6-hydroxy-7-methoxy-dehydroiso-α-lapachone (2), together with three known anthraquinones (3-5). Their structures were established on the basis of detailed spectroscopic analysis, including one- and two-dimensional NMR, ESI-MS, and HR-ESI-MS techniques. All the compounds were isolated from S. latifolia for the first time. Compounds 1, 2, 4, and 5 showed significant antibacterial activity toward Bacillus subtilis with MIC values ranging from 0.9 to 31.2 μg/ml, and compound 4 aslo exhibited antibacterial activity against Bacillus cereus with a MIC value 62.5 μg/ml. Compound 1 was further revealed to show significant in vitro α-glucosidase inhibitory activity with IC 50 value of 0.653 mM.

  17. Phosphorus conservation by evergreenness of mountain laurel. [Kalmia latifolia

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, W A [Oak Ridge National Lab., TN; Grigal, D F

    1976-01-01

    Field studies and compartmental model analyses demonstrate that the evergreen nature of mountain laurel Kalmia latifolia L. helps conserve phosphorus on infertile sites. The perennial canopy continuously adds P to the forest floor through foliar leaching and year-round leaf fall. Slow mineralization of leaf litter provides a steady addition of available P. The evergreenness of Kalmia allows it to utilize increases in available P, thus keeping it in circulation through biological tissues. Retention of a sufficient P supply in this manner allows the site to respond when changes such as disturbance or succession occur in the system.

  18. Feasibility of reactivity worth measurements by perturbation method with Caliban and Silene experimental reactors

    Energy Technology Data Exchange (ETDEWEB)

    Casoli, Pierre; Authier, Nicolas [Commissariat a l' Energie Atomique, Centre d' Etudes de Valduc, 21120 Is-Sur-Tille (France)

    2008-07-01

    Reactivity worth measurements of material samples put in the central cavities of nuclear reactors allow to test cross section nuclear databases or to extract information about the critical masses of fissile elements. Such experiments have already been completed on the Caliban and Silene experimental reactors operated by the Criticality and Neutronics Research Laboratory of Valduc (CEA, France) using the perturbation measurement technique. Calculations have been performed to prepare future experiments on new materials, such as light elements, structure materials, fission products or actinides. (authors)

  19. High-level Zn and Cd tolerance in Silene paradoxa L. from a moderately Cd- and Zn-contaminated copper mine tailing

    International Nuclear Information System (INIS)

    Arnetoli, Miluscia; Vooijs, Riet; Gonnelli, Cristina; Gabbrielli, Roberto; Verkleij, Jos A.C.; Schat, Henk

    2008-01-01

    Cadmium and zinc tolerance were examined in populations of Silene paradoxa, one from uncontaminated calcareous soil (CVD) and one from a mine tailing (FC) (Cd < 1-15 ppm, Zn 400-1300 ppm, pH 2-6). The mine population exhibited extremely high Zn and Cd tolerance levels, although the degrees of Cd and Zn enrichment relatively low at the population site. Cd and Zn hypertolerance in FC were associated with reduced rates of accumulation of these metals, both in roots and shoots (Cd), or exclusively in shoots (Zn). However, exclusion potentially explained only a minor part of the superior tolerance in FC. Cd hypertolerance in FC was associated with decreased, rather than enhanced phytochelatin accumulation. The remarkably high levels of Cd and Zn hypertolerance in FC might relate to the low soil pH, due to oxidation of sulphide minerals, and the absence of soil organic matter at the FC site. - Silene paradoxa from a copper mine exhibits extreme levels of Zn and Cd tolerance

  20. Phenolic compounds from the roots of Valeriana officinalis var. latifolia

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Peng-Cheng; Ran, Xin-Hui; Luo, Huai-Rong; Liu, Yu-Qing; Zhou Jun [State Key Laboratory of Phytochemistry and Plant Resources in West China. Kunming Institute of Botany, Chinese Academy of Sciences (China); Ma, Qing-Yun; Zhao, You-Xing, E-mail: zhoujun3264@yahoo.com.cn, E-mail: zhaoyouxing@itbb.org.cn [Key Laboratory of Biology and Genetic Resources of Tropical Crops. Ministry of Agriculture, Institute of Tropical Bioscience and Biotechnology. Chinese Academy of Tropical Agriculture Sciences (China)

    2013-09-15

    A new benzofuran neolignan, dihydrodehydrodiconiferyl alcohol 9-isovalerate, along with ten known phenolic compounds, olivil, pinoresinol, 8-hydroxypinoresinol, pinorespiol, 8-hydroxy- 7-epipinoresinol, trans-p-hydroxyphenyl- propenoic acid, cis-p-hydroxyphenyl-propenoic acid, ferulic acid, isoferulic acid and isovanillin were isolated from the roots of Valeriana officinalis var. latifolia. Their structures and configurations were elucidated on the basis of spectroscopic methods. The inhibitory activity for acetylcholinesterase (AChE) and enhancing activity on nerve growth factor (NGF)-mediated neurite outgrowth in PC12 cells of dihydrodehydrodiconiferyl alcohol 9-isovaterate and olivil were evaluated. (author)

  1. Phenolic compounds from the roots of Valeriana officinalis var. latifolia

    International Nuclear Information System (INIS)

    Wang, Peng-Cheng; Ran, Xin-Hui; Luo, Huai-Rong; Liu, Yu-Qing; Zhou Jun; Ma, Qing-Yun; Zhao, You-Xing

    2013-01-01

    A new benzofuran neolignan, dihydrodehydrodiconiferyl alcohol 9-isovalerate, along with ten known phenolic compounds, olivil, pinoresinol, 8-hydroxypinoresinol, pinorespiol, 8-hydroxy- 7-epipinoresinol, trans-p-hydroxyphenyl- propenoic acid, cis-p-hydroxyphenyl-propenoic acid, ferulic acid, isoferulic acid and isovanillin were isolated from the roots of Valeriana officinalis var. latifolia. Their structures and configurations were elucidated on the basis of spectroscopic methods. The inhibitory activity for acetylcholinesterase (AChE) and enhancing activity on nerve growth factor (NGF)-mediated neurite outgrowth in PC12 cells of dihydrodehydrodiconiferyl alcohol 9-isovaterate and olivil were evaluated. (author)

  2. Phragmites australis + Typha latifolia Community Enhanced the Enrichment of Nitrogen and Phosphorus in the Soil of Qin Lake Wetland

    Directory of Open Access Journals (Sweden)

    Zhiwei Ge

    2017-01-01

    Full Text Available Aquatic plants play an essential role and are effective in mitigating lake eutrophication by forming complex plant-soil system and retaining total nitrogen (TN and phosphorus (TP in soils to ultimately reduce their quantities in aquatic systems. Two main vegetation types (Phragmites australis community and P. australis + Typha latifolia community of Qin Lake wetland were sampled in this study for the analysis of TN and TP contents and reserves in the wetland soils. The results showed that (1 the consumption effect of Qin Lake wetland on soluble N was much more significant than on soluble P. (2 The efficiency of TN enrichment in wetland soil was enhanced by vegetation covering of P. australis and T. latifolia. (3 Wetland soil P was consumed by P. australis community and this pattern was relieved with the introduction of T. latifolia. (4 According to the grey relativity analysis, the most intensive interaction between plants and soil occurred in summer. In addition, the exchange of N in soil-vegetation system primarily occurred in the 0–15 cm soil layer. Our results indicated that vegetation covering was essential to the enrichment of TN and TP, referring to the biology-related fixation in the wetland soil.

  3. Three new constituents, latifolinal, latifolidin and cordicinol, from the fruits and leaves of Cordia latifolia.

    Science.gov (United States)

    Siddiqui, Bina S; Perwaiz, Sobiya; Begum, Sabira; Ali, S Tariq

    2010-01-01

    Isolation and structure elucidation of three new natural constituents are reported. These include a new substituted furfuryl ester of stearic acid, latifolinal (1), and two aromatic compounds, latifolidin (2) and cordicinol (3). Compounds 1 and 2 were obtained from the dried fruits and compound 3 from the leaves of Cordia latifolia.

  4. The 2″-O-glucosylation of vitexin and isovitexin in petals of Silene alba is catalysed by two different enzymes

    NARCIS (Netherlands)

    Heinsbroek, R.; Brederode, J. van; Nigtevecht, G. van; Maas, J.; Kamsteeg, J.; Besson, E.; Chopin, J.

    1980-01-01

    Two separate genes, Fg and Vg, which govern the presence of isovitexin 2″-O-glucoside and vitexin 2″-O-glucoside respectively in the petals of Silene alba control different glucosyltransferases. In Vg/Vg,fg/fg plants no isovitexin 2″-O-glucosyltransferase was present and in vg/vg,Fg/Fg plants no

  5. A new species of Chelonus (Areselonus) (Hymenoptera, Braconidae) from India reared from Acrocercops lysibathra (Meyrick) on Cordia latifolia Roxb.

    OpenAIRE

    Ahmad, Zubair; Ghramh, Hamed A.

    2018-01-01

    Chelonus (Areselonus) spinigaster sp. n., (Hymenoptera: Braconidae: Cheloninae) is described from India. The new species was reared from the moth species Acrocercops lysibathra (Meyr.) on Cordia latifolia Roxb.

  6. A new species of Chelonus (Areselonus) (Hymenoptera, Braconidae) from India reared from Acrocercops lysibathra (Meyrick) on Cordia latifolia Roxb.

    Science.gov (United States)

    Ahmad, Zubair; Ghramh, Hamed A

    2018-01-01

    Chelonus (Areselonus) spinigaster sp. n. , (Hymenoptera: Braconidae: Cheloninae) is described from India. The new species was reared from the moth species Acrocercops lysibathra (Meyr.) on Cordia latifolia Roxb.

  7. Interrelationships among light, photosynthesis and nitrogen in the crown of mature Pinus contorta ssp. latifolia

    Science.gov (United States)

    A. W. Schoettle; W. K. Smith

    1999-01-01

    Scaling leaf-level measurements to estimate carbon gain of entire leaf crowns or canopies requires an understanding of the distribution of photosynthetic capacity and corresponding light microenvironments within a crown. We have compared changes in the photosynthetic light response and nitrogen (N) content (per unit leaf area) of Pinus contorta Dougl. ssp. latifolia...

  8. GENETIC DIVERSITY OF TYPHA LATIFOLIA (TYPHACEAE) AND THE IMPACT OF POLLUTANTS EXAMINED WITH TANDEM-REPETITIVE DNA PROBES

    Science.gov (United States)

    Genetic diversity at variable-number-tandem-repeat (VNTR) loci was examined in the common cattail, Typha latifolia (Typhaceae), using three synthetic DNA probes composed of tandemly repeated "core" sequences (GACA, GATA, and GCAC). The principal objectives of this investigation w...

  9. Effect of Copper on Fatty-Acid Composition and Peroxidation of Lipids in the Roots of Copper Tolerant and Sensitive Silene-Cucubalus.

    NARCIS (Netherlands)

    De Vos, C.H.R.; TenBookum, W.M.; Vooijs, R.; Schat, H.; De Kok, L.J.

    1993-01-01

    The effect of high copper exposure in vivo on the lipid and fatty acid composition and lipid peroxidation was studied in the roots of plants from one copper sensitive and two copper tolerant genotypes of Silene cucubalus. At 0.5 muM Cu (control treatment) the compositions of lipids and fatty acids

  10. New xenophytes from La Palma (Canary Islands, Spain, with emphasis on naturalized and (potentially invasive species

    Directory of Open Access Journals (Sweden)

    R. Otto

    2016-07-01

    Full Text Available Many years of field work in La Palma (western Canary Islands yielded a number of interesting new records of non-native vascular plants. Amaranthus blitoides, A. deflexus, Aptenia cordifolia, Argemone ochroleuca, Begonia schmidtiana, Capsella rubella, Cardamine hamiltonii, Centratherum punctatum, Cerastium fontanum subsp. vulgare, Chasmanthe floribunda (widely confused with C. aethiopica and Crocosmia xcrocosmiiflora in Macaronesia, Chenopodium probstii, Commelina latifolia var. latifolia, Dichondra micrantha, Dysphania anthelmintica, Epilobium ciliatum, Erigeron sumatrensis, Erodium neuradifolium, Eucalyptus globulus, Euphorbia hypericifolia, E. maculata, Gamochaeta antillana, Geranium pyrenaicum, Hedychium coronarium, Hypochaeris radicata, Kalanchoe daigremontiana, K. delagoensis, K. xhoughtonii, Kickxia commutata subsp. graeca, K. spuria subsp. integrifolia, Lactuca viminea subsp. ramosissima, Landoltia punctata, Malvastrum coromandelianum subsp. capitatospicatum, Oenothera jamesii, Orobanche nana, Oxalis latifolia, Papaver hybridum, P. setigerum, Pilea microphylla, Podranea ricasoliana, Polygonum arenastrum, Portulaca granulatostellulata, P. nicaraguensis, P. nitida, P. papillatostellulata, Rumex crispus subsp. crispus, R. pulcher subsp. pulcher, R. xpratensis, Sechium edule, Sida spinosa var. angustifolia, Silene nocturna, Solanum abutiloides, S. alatum, S. decipiens, Sonchus tenerrimus, Spergularia marina, Stellaria pallida, Tragopogon porrifolius subsp. australis, Tribulus terrestris and Trifolium repens subsp. repens are naturalized or (potentially invasive xenophytes, reported for the first time from either the Canary Islands or from La Palma. 37 additional, presumably ephemeral taxa are reported for the first time from the Canary Islands, whereas 56 ephemeral taxa are new for La Palma..

  11. Evaluation of the concrete shield compositions from the 2010 criticality accident alarm system benchmark experiments at the CEA Valduc SILENE facility

    International Nuclear Information System (INIS)

    Miller, Thomas Martin; Celik, Cihangir; Dunn, Michael E; Wagner, John C; McMahan, Kimberly L; Authier, Nicolas; Jacquet, Xavier; Rousseau, Guillaume; Wolff, Herve; Savanier, Laurence; Baclet, Nathalie; Lee, Yi-kang; Trama, Jean-Christophe; Masse, Veronique; Gagnier, Emmanuel; Naury, Sylvie; Blanc-Tranchant, Patrick; Hunter, Richard; Kim, Soon; Dulik, George Michael; Reynolds, Kevin H.

    2015-01-01

    In October 2010, a series of benchmark experiments were conducted at the French Commissariat a l'Energie Atomique et aux Energies Alternatives (CEA) Valduc SILENE facility. These experiments were a joint effort between the United States Department of Energy Nuclear Criticality Safety Program and the CEA. The purpose of these experiments was to create three benchmarks for the verification and validation of radiation transport codes and evaluated nuclear data used in the analysis of criticality accident alarm systems. This series of experiments consisted of three single-pulsed experiments with the SILENE reactor. For the first experiment, the reactor was bare (unshielded), whereas in the second and third experiments, it was shielded by lead and polyethylene, respectively. The polyethylene shield of the third experiment had a cadmium liner on its internal and external surfaces, which vertically was located near the fuel region of SILENE. During each experiment, several neutron activation foils and thermoluminescent dosimeters (TLDs) were placed around the reactor. Nearly half of the foils and TLDs had additional high-density magnetite concrete, high-density barite concrete, standard concrete, and/or BoroBond shields. CEA Saclay provided all the concrete, and the US Y-12 National Security Complex provided the BoroBond. Measurement data from the experiments were published at the 2011 International Conference on Nuclear Criticality (ICNC 2011) and the 2013 Nuclear Criticality Safety Division (NCSD 2013) topical meeting. Preliminary computational results for the first experiment were presented in the ICNC 2011 paper, which showed poor agreement between the computational results and the measured values of the foils shielded by concrete. Recently the hydrogen content, boron content, and density of these concrete shields were further investigated within the constraints of the previously available data. New computational results for the first experiment are now available

  12. Genetic variation of inbreeding depression among floral and fitness traits in Silene nutans

    DEFF Research Database (Denmark)

    Thiele, Jan; Hansen, Thomas Møller; Siegismund, Hans Redlef

    2010-01-01

    The magnitude and variation of inbreeding depression (ID) within populations is important for the evolution and maintenance of mixed mating systems. We studied ID and its genetic variation in a range of floral and fitness traits in a small and large population of the perennial herb Silene nutans......, using controlled pollinations in a fully factorial North Carolina II design. Floral traits and early fitness traits, that is seed mass and germination rate, were not much affected by inbreeding (delta0.4). Lack of genetic correlations indicated that ID in floral, early and late traits is genetically...... was statistically significant in most floral and all seed traits, but not in late fitness traits. However, some paternal families had delta...

  13. Molecular characterisation of four double-flowered mutants of Silene dioica representing four centuries of variation

    Science.gov (United States)

    Ingle, Elizabeth K. S.; Gilmartin, Philip M.

    2015-01-01

    Records of double-flowered Silene dioica date from the late sixteenth century and four named varieties are grown today, as previously, for their horticultural interest. Although double-flowered mutants have been characterized in several plants, their study in dioecious species is of particular interest due to influences of the homeotic mutation on the different floral whorl configurations in males and females. We have analysed four double-flowered varieties of Silene dioica: Flore Pleno and Rosea Plena date back to the seventeenth and nineteenth centuries, Thelma Kay and Firefly were recognized in the latter part of the twentieth and early twenty-first centuries. We have analysed the floral structure of the four varieties, which have distinct floral architectures. Based on Y chromosome-specific PCR analysis we show that Firefly is male and that the other three varieties are female: Random Amplification of Polymorphic DNA (RAPD) analyses suggested a common origin for the three female varieties. The double-flowered phenotype in all four varieties is caused by mutation of the C-function MADS-box transcription factor gene SDM1. We show that Firefly carries a unique 44bp insertion into SDM1, revealing an independent origin for this variety. Comparative analysis of SDM1 cDNA and genomic sequences in Flore Pleno, Rosea Plena and Thelma Kay shows that all three are caused by the same 7bp insertion within SDM1 and therefore share a common origin. The three alleles also differ by several single nucleotide polymorphisms, which represent somatic mutations accumulated over four centuries of asexual propagation. PMID:25878355

  14. The fate of arsenic, cadmium and lead in Typha latifolia: A case study on the applicability of micro-PIXE in plant ionomics

    International Nuclear Information System (INIS)

    Lyubenova, Lyudmila; Pongrac, Paula; Vogel-Mikuš, Katarina; Mezek, Gašper Kukec; Vavpetič, Primož; Grlj, Nataša; Regvar, Marjana; Pelicon, Primož; Schröder, Peter

    2013-01-01

    Highlights: ► Uptake, accumulation and distribution of multi-elemental pollution. ► Quantitative analysis of the spatal distribution of nutrients in roots and rhizomes. ► Typha latifolia – plant species important for phytoremediation of hazardous xenobiotics. ► Low amounts of Cd and Pb in the inner tissues of roots and rhizomes. ► Predominantly As was found within the vascular tissue – high mobility of the element. -- Abstract: Understanding the uptake, accumulation and distribution of toxic elements in plants is crucial to the design of effective phytoremediation strategies, especially in the case of complex multi-element pollution. Using micro-proton induced X-ray emission, the spatial distribution of Na, Mg, Al, Si, P, S, Cl, K, Ca, Mn, Fe, Zn, As, Br, Rb, Sr, Cd and Pb have been quantitatively resolved in roots and rhizomes of an obligate wetland plant species, Typha latifolia, treated with a mixture of 100 μM each of As, Cd and Pb, together. The highest concentrations of As, Cd and Pb were found in the roots of the T. latifolia, with tissue-specific distributions. The As was detected in the root rhizodermis, and in the rhizome the majority of the As was within the vascular tissues, which indicates the high mobility of As within T. latifolia. The Cd was detected in the root exodermis, and in the vascular bundle and epidermis of the rhizome. The highest Pb concentrations were detected in the root rhizodermis and exodermis, and in the epidermis of the rhizome. These data represent an essential step in the resolution of fundamental questions in plant ionomics

  15. The fate of arsenic, cadmium and lead in Typha latifolia: A case study on the applicability of micro-PIXE in plant ionomics

    Energy Technology Data Exchange (ETDEWEB)

    Lyubenova, Lyudmila [Helmholtz Zentrum München, German Research Centre for Environmental Health, Department of Environmental Sciences, Research Unit Microbe–Plant Interactions, Ingolstädter Landstr. 1, D-85764 Neuherberg (Germany); Pongrac, Paula; Vogel-Mikuš, Katarina [University of Ljubljana, Biotechnical Faculty, Department of Biology, Večna pot 111, SI-1000 Ljubljana (Slovenia); Mezek, Gašper Kukec; Vavpetič, Primož; Grlj, Nataša [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Regvar, Marjana [University of Ljubljana, Biotechnical Faculty, Department of Biology, Večna pot 111, SI-1000 Ljubljana (Slovenia); Pelicon, Primož [Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana (Slovenia); Schröder, Peter, E-mail: peter.schroeder@helmholtz-muenchen.de [Helmholtz Zentrum München, German Research Centre for Environmental Health, Department of Environmental Sciences, Research Unit Microbe–Plant Interactions, Ingolstädter Landstr. 1, D-85764 Neuherberg (Germany)

    2013-03-15

    Highlights: ► Uptake, accumulation and distribution of multi-elemental pollution. ► Quantitative analysis of the spatal distribution of nutrients in roots and rhizomes. ► Typha latifolia – plant species important for phytoremediation of hazardous xenobiotics. ► Low amounts of Cd and Pb in the inner tissues of roots and rhizomes. ► Predominantly As was found within the vascular tissue – high mobility of the element. -- Abstract: Understanding the uptake, accumulation and distribution of toxic elements in plants is crucial to the design of effective phytoremediation strategies, especially in the case of complex multi-element pollution. Using micro-proton induced X-ray emission, the spatial distribution of Na, Mg, Al, Si, P, S, Cl, K, Ca, Mn, Fe, Zn, As, Br, Rb, Sr, Cd and Pb have been quantitatively resolved in roots and rhizomes of an obligate wetland plant species, Typha latifolia, treated with a mixture of 100 μM each of As, Cd and Pb, together. The highest concentrations of As, Cd and Pb were found in the roots of the T. latifolia, with tissue-specific distributions. The As was detected in the root rhizodermis, and in the rhizome the majority of the As was within the vascular tissues, which indicates the high mobility of As within T. latifolia. The Cd was detected in the root exodermis, and in the vascular bundle and epidermis of the rhizome. The highest Pb concentrations were detected in the root rhizodermis and exodermis, and in the epidermis of the rhizome. These data represent an essential step in the resolution of fundamental questions in plant ionomics.

  16. Heat stability of proteins in desiccation tolerant cattail pollen (Typha latifolia): A Fourier transform infrared spectroscopic study.

    NARCIS (Netherlands)

    Wolkers, W.F.; Hoekstra, F.A.

    1997-01-01

    Secondary structure and aggregation behavior of proteins, as determined in situ in Typha latifolia pollen, were studied by means of Fourier transform infrared microspectroscopy. The amide-I band, arising from the peptide backbone, was recorded over a temperature range from -50 to 120°C at different

  17. EVALUACIÓN DE PANELES AISLANTES FABRICADOS EN FIBRAS DE TOTORA (TYPHA LATIFOLIA

    Directory of Open Access Journals (Sweden)

    Velasco, L.

    2015-12-01

    Full Text Available En el presente trabajo se evaluó la capacidad aislante de paneles elaborados a base de la Typha Latifolia en diferentes formas. Los resultados muestran una capacidad aislante relevante, catalogando la totora como un elemento de potencial aplicación como aislamiento en edificaciones. El desarrollo de aislantes térmicos basados en residuos de biomasa es una línea de investigación prometedora que permitirá la mejora sustancial de la eficiencia energética, así como el confort térmico del hábitat con soluciones sustentables de bajo coste. El desarrollo de elementos constructivos contemporáneos como paneles o mantas de totora, permitirá la mejora de la sustentabilidad de soluciones industriales, así como la reducción importante del coste de producción de estas. In this paper the insulating capacity of panels made of Typha latifolia in different forms was evaluated. The results show a significant insulating capacity, placing the cattail as a potential isolating element in buildings. The development of thermal insulation elements based on biomass residues is a promising line of research that will provide substantial improvement in energy efficiency and thermal comfort with sustainable habitat solutions at low cost. The development of contemporary construction elements such as panels or blankets of totora, will permit the improvement of industrial solutions sustainability and a significant reduction in the cost of its production.

  18. Distribución y uso tradicional de Sagittaria macrophylla Zucc. y S. latifolia Willd. en el Estado de México

    Directory of Open Access Journals (Sweden)

    Carmen Zepeda Gómez

    2005-01-01

    Full Text Available Sagittaria macrophylla y S. latifolia son plantas acuáticas emergentes que crecen en las orillas y zonas poco profundas de los cuerpos de agua limpios y de poca corriente. La primera es endémica de México, su distribución se restringe a la región del río Lerma y valle de México y está en peligro de extinción. Sagittarial latifolia se distribuye desde Canadá hasta el noroeste de Sudamérica. En México se localiza al menos en 11 estados. El análisis de la distribución de ambas especies muestra una disminución en el Estado de México; los factores que aparentemente están contribuyendo a este fenómeno son, en general, la explosión demográfica, la pérdida del hábitat y la sobreexplotación. No había registros del uso de S. latifolia en México, actualmente se reconoce que sus tubérculos o ‘papas de agua’ tienen importancia económica en la región del río Lerma. El uso tradicional de ambas especies indica que podrían ser una alternativa más en la dieta humana y animal.

  19. Ultrastructural morphologic description of the wild rice species Oryza latifolia (Poaceae in Costa Rica

    Directory of Open Access Journals (Sweden)

    Ethel Sánchez

    2003-06-01

    Full Text Available The wild rice species Oryza latifolia is endemic to Tropical America, allotetraploid and has a CCDD genome type. It belongs to the officinalis group of the genus Oryza. This species is widely distributed through-out the lowlands of Costa Rica and it is found on different life zones, having great morphologic diversity. The purpose of this research is to perform a morphologic description of O. latifolia samples of three Costa Rican localities (Carara, Liberia and Cañas and to see if the phenotypic diversity of the species is reflected at the ultra-structure level. Structures such as the leaf blade, ligule, auricles and spikelet were analyzed. Leaf blade morphology of the specimens from the three localities is characterized by the presence of diamond-shaped stomata with papillae, zipper-like rows of silica cells; a variety of evenly distributed epicuticular wax papillae and bulky prickle trichomes. The central vein of the leaf blade from the Cañas populations is glabrous, while those from Carara and Liberia have abundant papillae. There are also differences among the borders of the leaf blade between these locations. Cañas and Liberia present alternating large and small prickle trichomes ca. 81 and 150 µm, while Carara exhibits even sized prickle trichomes of ca. 93 µm. Auricles from Cañas are rectangular and present long trichomes along the surface ca. 1.5 mm, while those of Liberia and Carara wrap the culm and exhibit trichomes only in the borders. The ligule from the plants of Carara has an acute distal tip, while that of Cañas and Liberia is blunt. The Liberia spikelet has large lignified spines while Cañas and Carara show flexible trichomes.La especie silvestre Oryza latifolia es endémica de América, tetraploide y de genoma CCDD. Pertenece a las especies del género Oryza del grupo officinalis. Presenta una amplia distribución en las tierras bajas de Costa Rica y se le encuentra en varias zonas de vida, mostrando una gran diversidad

  20. Accumulation of chloroplast DNA sequences on the Y chromosome of Silene latifolia

    Czech Academy of Sciences Publication Activity Database

    Kejnovský, Eduard; Kubát, Zdeněk; Hobza, Roman; Lengerová, Martina; Sato, S.; Tabata, S.; Fukui, K.; Matsunaga, S.; Vyskot, Boris

    2006-01-01

    Roč. 128, 1-3 (2006), s. 167-175 ISSN 0016-6707 R&D Projects: GA ČR(CZ) GA204/05/2097; GA ČR(CZ) GD204/05/H505; GA AV ČR(CZ) 1QS500040507 Institutional research plan: CEZ:AV0Z50040507 Keywords : accumulation * chloroplast DNA * Y chromosome Subject RIV: BO - Biophysics Impact factor: 1.492, year: 2006

  1. By-product of Lavandula latifolia essential oil distillation as source of antioxidants

    Directory of Open Access Journals (Sweden)

    Inés Méndez-Tovar

    2015-06-01

    Full Text Available The objective of this work was to evaluate the antioxidant properties of Lavandula latifolia waste obtained after essential oil distillation. Samples of 12 wild populations of the Lavandula genus collected between 2009 and 2010 were hydrodistilled and their by-products were analyzed using the Folin–Ciocalteu, free radical scavenging activity (2,2-diphenyl-1-picrylhydrazyl, and the ferric reducing antioxidant power (FRAP methods. Rosmarinic acid, apigenin, and luteolin contents were analyzed by high-performance liquid chromatography–diode array detection. The mean of total phenolic content ranged from 1.89 ± 0.09 mg gallic acid equivalents/g dry weight to 3.54 ± 0.22 mg gallic acid equivalents/g dry weight. The average value of the half maximal effective concentration (EC50 for scavenging activity ranged from 5.09 ± 0.17 mg/mL to 14.30 ± 1.90 mg/mL and the variability of the EC50 in FRAP ranged from 3.72 ± 0.12 mg/mL to 18.55 ± 0.77 mg/mL. Annual variation was found among this samples and the environmental conditions of 2009 were found to be more favorable. The plants collected from Sedano showed the highest antioxidant power. Our results show that rosmarinic acid and apigenin in L. latifolia contributed to the antioxidant properties of the waste. In conclusion, the by-product of the distillation industry could be valorizing as a source of natural antioxidants.

  2. Review of the CRAC and SILENE Criticality Accident Studies

    International Nuclear Information System (INIS)

    Barbry, F.; Fouillaud, P.; Grivot, P.; Reverdy, L.

    2009-01-01

    In 1967, the Commissariat et l'Energie Atomique (French Atomic Energy Agency) performed its first research on criticality accidents for the purpose of limiting their impact on people, the environment, and nuclear facilities themselves. A criticality accident is accompanied by intense neutron and gamma emissions and release of radioactive fission products-gases and aerosols-gene rating risk of irradiation and contamination. This work has supplemented earlier work in criticality safety, which concentrated on critical mass measurements and computations. Understanding of the consequences of criticality accidents was limited. Emergency planning was hampered by lack of data. Information became available from pulsed reactor experiments, but the experiments were restricted to the established reactor configurations. The objectives of research performed at the Valduc criticality laboratory, mainly on aqueous fissile media, using the CRAC and SILENE facilities, by multidisciplinary teams of physicists, dosimetry specialists, and radio-biologists, were to model criticality accident physics, estimate irradiation risks and radioactive releases, detect excursions, and organize emergency response. The results of the Valduc experiments have contributed toward improved understanding of criticality accident phenomenology and better evaluation of the risks associated with such accidents. (authors)

  3. Review of the CRAC and SILENE Criticality Accident Studies

    Energy Technology Data Exchange (ETDEWEB)

    Barbry, F.; Fouillaud, P.; Grivot, P.; Reverdy, L. [CEA Valduc, Serv Rech Neutron and Critcite, 21 - Is-sur-Tille (France)

    2009-02-15

    In 1967, the Commissariat et l'Energie Atomique (French Atomic Energy Agency) performed its first research on criticality accidents for the purpose of limiting their impact on people, the environment, and nuclear facilities themselves. A criticality accident is accompanied by intense neutron and gamma emissions and release of radioactive fission products-gases and aerosols-gene rating risk of irradiation and contamination. This work has supplemented earlier work in criticality safety, which concentrated on critical mass measurements and computations. Understanding of the consequences of criticality accidents was limited. Emergency planning was hampered by lack of data. Information became available from pulsed reactor experiments, but the experiments were restricted to the established reactor configurations. The objectives of research performed at the Valduc criticality laboratory, mainly on aqueous fissile media, using the CRAC and SILENE facilities, by multidisciplinary teams of physicists, dosimetry specialists, and radio-biologists, were to model criticality accident physics, estimate irradiation risks and radioactive releases, detect excursions, and organize emergency response. The results of the Valduc experiments have contributed toward improved understanding of criticality accident phenomenology and better evaluation of the risks associated with such accidents. (authors)

  4. Radical Scavenging Capacity of Methanolic Phillyrea latifolia L. Extract: Anthocyanin and Phenolic Acids Composition of Fruits

    Directory of Open Access Journals (Sweden)

    Naciye Erkan

    2013-01-01

    Full Text Available Radical scavenging capacity of a crude methanolic extract from the fruits of Phillyrea latifolia L., commonly known as green olive tree or mock privet, was investigated with reference to anthocyanin standards, as flavonoids, and phenolic acid standards, as phenylpropanoids. Characterization with high performance liquid chromatography-diode array detection (HPLC-DAD indicated the presence of keracyanin, kuromanin, cyanidin, ferulic acid, caffeic acid and rosmarinic acid at amounts of 289.1, 90.4, 191.4, 225.2, 221.2 and 190.1 mg/100 g fresh weight (FW of fruits, respectively. Chlorogenic and p-coumaric acids were found to exist in lower amounts. Trolox equivalent antioxidant capacity (TEAC and IC50 values of the plant extract were found to be 1.8 mM Trolox equivalents (TE/g FW of fruits and 69.4 µg/mL, respectively, indicating the close radical scavenging activity of the extract to those of keracyanin and p-coumaric acid. The crude methanolic P. latifolia L. fruit extract was seen to be fairly potent in radical scavenging. Total phenolic content (TPC of the plant extract was found to be 1652.9 mg gallic acid equivalent (GAE/100 g FW of fruits.

  5. By-product of Lavandula latifolia essential oil distillation as source of antioxidants.

    Science.gov (United States)

    Méndez-Tovar, Inés; Herrero, Baudilio; Pérez-Magariño, Silvia; Pereira, José Alberto; Asensio-S-Manzanera, M Carmen

    2015-06-01

    The objective of this work was to evaluate the antioxidant properties of Lavandula latifolia waste obtained after essential oil distillation. Samples of 12 wild populations of the Lavandula genus collected between 2009 and 2010 were hydrodistilled and their by-products were analyzed using the Folin-Ciocalteu, free radical scavenging activity (2,2-diphenyl-1-picrylhydrazyl), and the ferric reducing antioxidant power (FRAP) methods. Rosmarinic acid, apigenin, and luteolin contents were analyzed by high-performance liquid chromatography-diode array detection. The mean of total phenolic content ranged from 1.89 ± 0.09 mg gallic acid equivalents/g dry weight to 3.54 ± 0.22 mg gallic acid equivalents/g dry weight. The average value of the half maximal effective concentration (EC 50 ) for scavenging activity ranged from 5.09 ± 0.17 mg/mL to 14.30 ± 1.90 mg/mL and the variability of the EC 50 in FRAP ranged from 3.72 ± 0.12 mg/mL to 18.55 ± 0.77 mg/mL. Annual variation was found among this samples and the environmental conditions of 2009 were found to be more favorable. The plants collected from Sedano showed the highest antioxidant power. Our results show that rosmarinic acid and apigenin in L. latifolia contributed to the antioxidant properties of the waste. In conclusion, the by-product of the distillation industry could be valorizing as a source of natural antioxidants. Copyright © 2014. Published by Elsevier B.V.

  6. Studies on Colombian cryptogams XVII. On a new antipodal element in the Neotropical Paramos-Dendrocryphaea latifolia sp.nov. (Musci)

    NARCIS (Netherlands)

    Griffin, D.; Gradstein, S.R.; Aguirre C., J.

    1982-01-01

    Dendrocryphaea latifolia sp.nov. from the Páramo de Chisacá, Colombia is described and illustrated. It is allied to D. cuspidata from austral South America but differs from that species in the broader leaves, globose capsules and the basally smooth exostome teeth. A key to the four species of

  7. The role of chromosomal rearrangements in the evolution of Silene latifolia sex chromosomes

    Czech Academy of Sciences Publication Activity Database

    Hobza, Roman; Kejnovský, Eduard; Vyskot, Boris; Widmer, A.

    2007-01-01

    Roč. 278, č. 6 (2007), s. 633-638 ISSN 1617-4615 R&D Projects: GA ČR(CZ) GA204/05/2097; GA ČR(CZ) GA521/06/0056 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : chromosomal rearrangements * sex chromosomes * FISH Subject RIV: BO - Biophysics Impact factor: 2.978, year: 2007

  8. Breeding system in the dichogamous hermaphrodite Silene acutifolia (Caryophyllaceae).

    Science.gov (United States)

    Buide, M L; Guitian, J

    2002-12-01

    The breeding system of the dichogamous hermaphrodite species Silene acutifolia, endemic to north-west Spain and north and central Portugal, is examined. Pollen germinability and style-stigma receptivity were analysed to determine whether protandry is a barrier to self-fertilization. By 48 h after anthesis, pollen germinability had declined to approx. 10 %. The short straight styles are not receptive when flowers first open. They gradually elongate and curve outwards, develop stigma papillae and become receptive. There is no clear separation between stigma and style: the stigma papillae appear in a line along the length of the style. Fruit set is high regardless of pollen source; however, seed set is significantly reduced after both spontaneous and facilitated autogamy. Seed set following spontaneous autogamy was 30 % (86 % in controls) in 1998 and 33 % (87 % in controls) in 1999. Seed set following facilitated autogamy was 62 % (86 % in controls) in 1998 and 67 % (89 % in controls) in 1999. Thus, separation of the male and female phases does not prevent production of seeds by self-pollination, although it does reduce the likelihood of this. Furthermore, results of the present experiments indicate that this species has no self-incompatibility mechanisms (self-compatibility index = 0.98). The selfing rate in the study population was 0.41, which is supported by the lack of self-incompatibility systems and by the incomplete protandry. Copyright 2002 Annals of Botany Company

  9. Effect of pre-treatments on the germination of jasmin box (Phillyrea latifolia) seeds in Greece

    OpenAIRE

    Spyroglou, Gavriil; Radoglou, Kalliopi

    2017-01-01

    The major problem in seedlings production of jasmin box (Phillyrea latifolia) is the poor and irregular germination due to seed dormancy. The objective of the present study was to evaluate methods of seed pre-treatments to increase germination. The effect of different solutions of KOH and NaOH, wood ash lye, GA3 and cold or warm stratification on germination were evaluated. Sets of four replicates of 25 seeds were soaked for 24 hours in KOH and NaOH solutions of 0.2, 0.5, 1 and 2 %, in wood a...

  10. Mosaic origins of a complex chimeric mitochondrial gene in Silene vulgaris.

    Directory of Open Access Journals (Sweden)

    Helena Storchova

    Full Text Available Chimeric genes are significant sources of evolutionary innovation that are normally created when portions of two or more protein coding regions fuse to form a new open reading frame. In plant mitochondria astonishingly high numbers of different novel chimeric genes have been reported, where they are generated through processes of rearrangement and recombination. Nonetheless, because most studies do not find or report nucleotide variation within the same chimeric gene, evolution after the origination of these chimeric genes remains unstudied. Here we identify two alleles of a complex chimera in Silene vulgaris that are divergent in nucleotide sequence, genomic position relative to other mitochondrial genes, and expression patterns. Structural patterns suggest a history partially influenced by gene conversion between the chimeric gene and functional copies of subunit 1 of the mitochondrial ATP synthase gene (atp1. We identified small repeat structures within the chimeras that are likely recombination sites allowing generation of the chimera. These results establish the potential for chimeric gene divergence in different plant mitochondrial lineages within the same species. This result contrasts with the absence of diversity within mitochondrial chimeras found in crop species.

  11. Bioprospecting the Curculigoside-Cinnamic Acid-Rich Fraction from Molineria latifolia Rhizome as a Potential Antioxidant Therapeutic Agent

    Directory of Open Access Journals (Sweden)

    Der Jiun Ooi

    2016-06-01

    Full Text Available Increasing evidence from both experimental and clinical studies depicts the involvement of oxidative stress in the pathogenesis of various diseases. Specifically, disruption of homeostatic redox balance in accumulated body fat mass leads to obesity-associated metabolic syndrome. Strategies for the restoration of redox balance, potentially by exploring potent plant bioactives, have thus become the focus of therapeutic intervention. The present study aimed to bioprospect the potential use of the curculigoside-cinnamic acid-rich fraction from Molineria latifolia rhizome as an antioxidant therapeutic agent. The ethyl acetate fraction (EAF isolated from M. latifolia rhizome methanolic extract (RME contained the highest amount of phenolic compounds, particularly curculigoside and cinnamic acid. EAF demonstrated glycation inhibitory activities in both glucose- and fructose-mediated glycation models. In addition, in vitro chemical-based and cellular-based antioxidant assays showed that EAF exhibited high antioxidant activities and a protective effect against oxidative damage in 3T3-L1 preadipocytes. Although the efficacies of individual phenolics differed depending on the structure and concentration, a correlational study revealed strong correlations between total phenolic contents and antioxidant capacities. The results concluded that enriched phenolic contents in EAF (curculigoside-cinnamic acid-rich fraction contributed to the overall better reactivity. Our data suggest that this bioactive-rich fraction warrants therapeutic potential against oxidative stress-related disorders.

  12. A comparison of isozyme and quantitative genetic variation in Pinus contorta ssp. latifolia by F{sub ST}

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Rong-Cai; Yeh, F.C. [Univ. of Alberta, Edmonton (Canada); Yanchuk, A.D. [British Columbia Ministry of Forests (Canada)

    1996-03-01

    We employed F-statistics to analyze quantitative and isozyme variation among five populations of Pinus contorta ssp. latifolia, a wind-pollinated outcrossing conifer with wide and continuous distribution in west North America. Estimates of population differentiation (F{sub ST}) for six quantitative traits were compared with the overall estimate of the differentiation (F*{sub ST}) from 19 isozymes that tested neutral to examine whether similar evolutionary processes were involved in morphological and isozyme differentiation. While the F{sub ST} estimates for specific gravity, stem diameter, stem height and branch length were significantly greater than the F*{sub ST} estimate, as judged from the 95% confidence intervals by bootstrapping, the F{sub ST} estimates for branch angle and branch diameter were indistinguishable from the F*{sub ST} estimate. Differentiation in stem height and stem diameter might reflect the inherent adaptation of the populations for rapid growth to escape suppression by neighboring plants during establishment and to regional differences in photoperiod, precipitation and temperature. In contrast, divergences in wood specific gravity and branch length might be correlated responses to population differentiation in stem growth. Possible bias in the estimation of F{sub ST} due to Hardy-Weinberg disequilibrium (F{sub IS} {ne} 0), linkage disequilibrium, maternal effects and nonadditive genetic effects was discussed with special reference to P. contorta ssp. latifolia. 48 refs., 1 fig., 3 tabs.

  13. Comportamiento de las exportaciones de limón persa (Citrus latifolia tanaka) al mercado de los Estados Unidos

    OpenAIRE

    Arias, Francisco; Suarez, Ernesto

    2017-01-01

    This paper aims to analyze the behavior of Persian lemon, also known as Tahiti lemon (Citrus latifolia Tanaka),exports to the United States market, which stands out as the main market worldwide, during 2011-2015. Materials and methods. Multiple databases were used, as well as the compilation of reports applicable to the citrus chain obtained from secondary sources for the three countries analyzed and interviews with experts from Mexico, Guatemala and Colombia. Ex...

  14. The distribution of a non-native (Rosa multiflora) and native (Kalmia latifolia) shrub in mature closed-canopy forests across soil fertility gradients

    Science.gov (United States)

    Cynthia D. Huebner; Jim Steinman; Todd F. Hutchinson; Todd E. Ristau; Alejandro A. Royo

    2014-01-01

    Background and aims. A soil fertility gradient, ranging from infertile to highly fertile soils, may define whether or not a plant will establish and spread at a site. We evaluated whether or not such a fertility gradient exists for Rosa multiflora Thunb., a nonnative invasive shrub, and Kalmia latifolia L., a...

  15. Ultraviolet-B (280-320 nm) absorbing pigments in the leaves of Silene vulgaris: their role in UV-B tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Staaij, J.W.M. van de; Ernst, W. H.O.; Hakvoort, H. W.J.; Rozema, J. [Vrije Univ., Amsterdam (Netherlands)

    1995-07-01

    The UV-B radiation tolerant perennial herb Silene vulgaris was tested on the influence of incident UV-B fluxes during growth on the synthesis of UV-B absorbing pigments in the leaves. Analysis of methanolic leaf extracts showed a stimulating effect of UV-B on the absorbing ability of leaf extracts. HPLC analysis made clear that UV-B radiation stimulated extractable flavonoid concentrations in leaves, but that UV-B absorption could only be partly attributed to these flavonoids. The contribution of flavonoids to UV-B absorption diminishes if plants mature. Other possible functions of flavonoids in plants growing under elevated UV-B conditions are discussed. (author)

  16. Ultraviolet-B (280-320 nm) absorbing pigments in the leaves of Silene vulgaris: their role in UV-B tolerance

    International Nuclear Information System (INIS)

    Staaij, J.W.M. van de; Ernst, W.H.O.; Hakvoort, H.W.J.; Rozema, J.

    1995-01-01

    The UV-B radiation tolerant perennial herb Silene vulgaris was tested on the influence of incident UV-B fluxes during growth on the synthesis of UV-B absorbing pigments in the leaves. Analysis of methanolic leaf extracts showed a stimulating effect of UV-B on the absorbing ability of leaf extracts. HPLC analysis made clear that UV-B radiation stimulated extractable flavonoid concentrations in leaves, but that UV-B absorption could only be partly attributed to these flavonoids. The contribution of flavonoids to UV-B absorption diminishes if plants mature. Other possible functions of flavonoids in plants growing under elevated UV-B conditions are discussed. (author)

  17. Night life on the beach: selfing to avoid pollinator competition between two sympatric Silene species.

    Science.gov (United States)

    Buide, M Luisa; del Valle, José Carlos; Pissatto, Mônica; Narbona, Eduardo

    2015-08-01

    Evolution of autonomous selfing may be advantageous because it allows for reproductive assurance. In co-flowering plants competing for pollinators, the least common and/or attractive could suffer pollen limitations. Silene niceensis and S. ramosissima are taxonomically related species sharing the same habitat, although S. ramosissima is less abundant and has a more restricted distribution. They also have the same a priori nocturnal pollinator syndrome, and show an overlapping flowering phenology. The aim of this study was to investigate whether a selfing strategy in S. ramosissima allows it to avoid pollinator competition and/or interspecific pollen transfer with S. niceensis, which would thus enable both species to reach high levels of fruit and seed set. The breeding system, petal colour, flower life span and degree of overlap between male and female phases, floral visitor abundance and visitation rates were analysed in two sympatric populations of S. niceensis and S. ramosissima in southern Spain. Autonomous selfing in S. ramosissima produced very high fruit and seed set, which was also similar to open-pollinated plants. Silene niceensis showed minimum levels of autonomous selfing, and pollen/ovule ratios were within the range expected for the breeding system. In contrast to S. niceensis, flower life span was much shorter in S. ramosissima, and male and female organs completely overlapped in space and time. Upper surface petals of both species showed differing brightness, chroma and hue. Flowers of S. niceensis were actively visited by moths, hawkmoths and syrphids, whereas those of S. ramosissima were almost never visited. The findings show that different breeding strategies exist between the sympatric co-flowering S. niceensis and S. ramosissima, the former specializing in crepuscular-nocturnal pollination and the latter mainly based on autonomous selfing. These two strategies allow both species to share the restricted dune habitat in which they exist, with a

  18. Vicariance, long-distance dispersal, and regional extinction-recolonization dynamics explain the disjunct circumpolar distribution of the arctic-alpine plant Silene acaulis.

    Science.gov (United States)

    Gussarova, Galina; Allen, Geraldine A; Mikhaylova, Yulia; McCormick, Laurie J; Mirré, Virginia; Marr, Kendrick L; Hebda, Richard J; Brochmann, Christian

    2015-10-01

    Many arctic-alpine species have vast geographic ranges, but these may encompass substantial gaps whose origins are poorly understood. Here we address the phylogeographic history of Silene acaulis, a perennial cushion plant with a circumpolar distribution except for a large gap in Siberia. We assessed genetic variation in a range-wide sample of 103 populations using plastid DNA (pDNA) sequences and AFLPs (amplified fragment length polymorphisms). We constructed a haplotype network and performed Bayesian phylogenetic analyses based on plastid sequences. We visualized AFLP patterns using principal coordinate analysis, identified genetic groups using the program structure, and estimated genetic diversity and rarity indices by geographic region. The history of the main pDNA lineages was estimated to span several glaciations. AFLP data revealed a distinct division between Beringia/North America and Europe/East Greenland. These two regions shared only one of 17 pDNA haplotypes. Populations on opposite sides of the Siberian range gap (Ural Mountains and Chukotka) were genetically distinct and appear to have resulted from postglacial leading-edge colonizations. We inferred two refugia in North America (Beringia and the southern Rocky Mountains) and two in Europe (central-southern Europe and northern Europe/East Greenland). Patterns in the East Atlantic region suggested transoceanic long-distance dispersal events. Silene acaulis has a highly dynamic history characterized by vicariance, regional extinction, and recolonization, with persistence in at least four refugia. Long-distance dispersal explains patterns across the Atlantic Ocean, but we found no evidence of dispersal across the Siberian range gap. © 2015 Botanical Society of America.

  19. Phytoremedial Potential of Typha latifolia, Eichornia crassipes and Monochoria hastata found in Contaminated Water Bodies Across Ranchi City (India).

    Science.gov (United States)

    Hazra, Moushumi; Avishek, Kirti; Pathak, Gopal

    2015-01-01

    Phytoremediation is an emerging technology that uses green plants (living machines) for removal of contaminants of concern (COC). These plant species have the potential to remove the COC, thereby restoring the original condition of soil or water environment. The present study focuses on assessing the heavy metals (COC) present in the contaminated water bodies of Ranchi city, Jharkhand, India. Phytoremedial potential of three plant species: Typha latifolia, Eichornia crassipes and Monochoria hastata were assessed in the present study. Heterogenous accumulation of metals was found in the three plant species. It was observed that the ratio of heavy metal concentration was different in different parts, i.e., shoots and roots. Positive results were also obtained for translocation factor of all species with minimum of 0.10 and maximum of 1. It was found experimentally that M. hastata has the maximum BFC for root as 4.32 and shoot as 2.70 (for Manganese). For T. latifolia, BCF of maximum was observed for root (163.5) and respective shoot 86.46 (for Iron), followed by 7.3 and 5.8 for root and shoot (for Manganese) respectively. E. crassipes was found to possess a maximum BCF of 278.6 (for Manganese and 151 (for Iron) and shoot as 142 (for Manganese) and 36.13 (for Iron).

  20. Chemical constituents of Cordia latifolia and their nematicidal activity.

    Science.gov (United States)

    Begum, Sabira; Perwaiz, Sobiya; Siddiqui, Bina S; Khan, Shazia; Fayyaz, Shahina; Ramzan, Musarrat

    2011-05-01

    Following nematicidal activity-guided isolation studies on the fruits, bark, and leaves of Cordia latifolia, two new constituents, cordinoic acid (=11-oxours-12-ene-23,28-dioic acid; 1) and cordicilin (=2-{[(E)-3-(3,4-dihydroxyphenyl)prop-2-enoyl]oxy}-3-[4-hydroxy-3-(stearoyloxy)phenyl]propanoic acid; 2) were isolated from the stem and leaves, respectively, together with nine known compounds, namely cordioic and cordifolic acid from the stem bark, latifolicin A-D and rosmarinic acid from the fruits, and cordinol and cordicinol from the leaves. Their structures were determined by means of spectroscopic analyses including 1D- and 2D-NMR techniques. The nematicidal activities of these constituents were determined against the root-knot nematode Meloidogyne incognita. Hundred percent mortality was caused by all of these after 72 h at a 0.125% concentration. Compound 1 and cordioic acid were most active and caused 100% mortality after 24 h at a 0.50% concentration. Furthermore, compound 2, the ester of rosemarinic acid, was found to be more active than the free acid. Copyright © 2011 Verlag Helvetica Chimica Acta AG, Zürich.

  1. Under fungal attack on a metalliferous soil: ROS or not ROS? Insights from Silene paradoxa L. growing under copper stress

    International Nuclear Information System (INIS)

    Taiti, Cosimo; Giorni, Elisabetta; Colzi, Ilaria; Pignattelli, Sara; Bazihizina, Nadia; Buccianti, Antonella; Luti, Simone; Pazzagli, Luigia; Mancuso, Stefano; Gonnelli, Cristina

    2016-01-01

    We investigated how the adaptation to metalliferous environments can influence the plant response to biotic stress. In a metallicolous and a non-metallicolous population of Silene paradoxa the induction of oxidative stress and the production of callose and volatiles were evaluated in the presence of copper and of the PAMP fungal protein cerato-platanin, separately and in combination. Our results showed incompatibility between the ordinary ROS-mediated response to fungal attack and the acquired mechanisms of preventing oxidative stress in the tolerant population. A similar situation was also demonstrated by the sensitive population growing in the presence of copper but, in this case, with a lack of certain responses, such as callose production. In addition, in terms of the joint behaviour of emitted volatiles, multivariate statistics showed that not only did the populations respond differently to the presence of copper or biotic stress, but also that the biotic and abiotic stresses interacted in different ways in the two populations. Our results demonstrated that the same incompatibility of hyperaccumulators in ROS-mediated biotic stress signals also seemed to be exhibited by the excluder metallophyte, but without the advantage of being able to rely on the elemental defence for plant protection from natural enemies. - Highlights: • Silene paradoxa plants from metalliferous and nonmetalliferous soil were studied. • Plants were exposed to Cerato-platanin in presence/absence of Cu in culture media. • ROS response was fully present in nonmetallicolous plants only in the absence of Cu. • Similar ROS response in metallicolous plants with or without Cu. - The adaptation to high concentrations of copper was found to interfere with the ordinary ROS-mediated response to fungal attack in an excluder metallophyte.

  2. Identifying new sex-linked genes through BAC sequencing in the dioecious plant Silene latifolia

    Czech Academy of Sciences Publication Activity Database

    Blavet, Nicolas; Blavet, Hana; Muyle, A.; Käfer, J.; Cegan, R.; Deschamps, C.; Zemp, N.; Mousset, S.; Aubourg, S.; Bergero, R.; Charlesworth, D.; Hobza, Roman; Widmer, A.; Marais, G.A.B.

    2015-01-01

    Roč. 16, JUL 25 (2015), s. 546 ISSN 1471-2164 R&D Projects: GA ČR GAP501/12/2220 Institutional support: RVO:61389030 Keywords : Sex chromosomes * Sex-linked genes * Plant Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.867, year: 2015

  3. Identifying new sex-linked genes through BAC sequencing in the dioecious plant Silene latifolia

    Czech Academy of Sciences Publication Activity Database

    Blavet, N.; Blavet, Hana; Muyle, A.; Kaefer, J.; Čegan, Radim; Deschamps, C.; Zemp, N.; Mousset, S.; Aubourg, S.; Bergero, R.; Charlesworth, D.; Hobza, Roman; Widmer, A.; Marais, G.A.B.

    2015-01-01

    Roč. 16, JUL 2015 (2015) ISSN 1471-2164 R&D Projects: GA ČR(CZ) GAP501/12/2220 Institutional support: RVO:68081707 Keywords : Y-CHROMOSOME * EVOLUTION * REARRANGEMENTS Subject RIV: BO - Biophysics Impact factor: 3.867, year: 2015

  4. Participation of IRD/CNEN-Br in International Intercomparison of Criticality Accident Dosimetry Systems at Silene reactor, France

    International Nuclear Information System (INIS)

    Mauricio, Claudia Lucia P.; Fonseca, Evaldo S. da

    1996-01-01

    IRD has participated in an International Intercomparison of Criticality Accident Dosimetry Systems at the SILENE reactor, France on June 1993. The dosemeters were irradiated on phantoms and free in air, in bare and lead shield reactor pulses, simulating different irradiation fields that can be found in criticality accidents. Comparing with the reference measurements, the calculated mean neutron kerma found by IRD was only 2% greater for lead shield and 14% greater for bare reactor. For gamma absorbed dose, the differences were, respectively + 22% and -9% for the dosemeters free in air and -19% and -9% for dosemeters on phantoms. IRD results are closer to the real values than the mean values measured by the participants. IRD results show a good performance if its simple criticality accident system. (author)

  5. Nutrient uptake from liquid digestate using ornamental aquatic macrophytes (Canna indica, Iris pseudacorus, Typha latifolia) in a constructed wetland system

    Science.gov (United States)

    Ediviani, W.; Priadi, C. R.; Moersidik, S. S.

    2018-05-01

    Indonesia has implemented energy recovery from organic (food) waste by anaerobic digestion method, but the digestate was commonly treated only by composting, and still as a separated treatment (not integrated into a resource recovery system). Whilst not getting any pretreatment, the digestate was disposed to the environment and then act as a pollutant. Yet it contains nutrients which could be recovered as a nutrient source for plants. The study was about how ornamental aquatic macrophytes could uptake nitrogen from liquid digestate in a constructed wetland method. Canna indica, Iris pseudacorus, and Typha latifolia were the experimented ornamental aquatic macrophytes used to uptake the nutrient (nitrogen—N) from liquid digestate. The study showed that the highest N uptake was done by C. indica (25.1%) which has the highest biomass increment as well (80.5%). Effluent quality improvement also shown by N removal by C. indica (68.5—76.4% TN), I. pseudacorus (61.8—71.3% TN), and T. latifolia (61.6—74.5%). This research proved that C. indica has the performance for the N uptake, best N removal efficiency, with a great growth rate as well. This system using C. indica could also improve the water quality of the effluent and add the aesthetic of environment.

  6. A taxonomic revision of the southern African native and naturalized species of Silene L. (Caryophyllaceae

    Directory of Open Access Journals (Sweden)

    J. C. Manning

    2012-12-01

    Full Text Available The native and naturalized species of Silene L. in southern Africa are reviewed, with full synonomy and the description of two new species from the West Coast of Western Cape. Eight native species and three naturalized species are recognized, including the first identification in southern Africa of the Mediterranean S. nocturna L. The identity of S. aethiopica Burm., which has remained unknown since its description, is established and is found to be the oldest name for S. clandestina Jacq. Patterns of morphological variation within each species are discussed and subspecies are recognized for geographically segregated groups of populations that are ± morphologically diagnosable. The following new names or combinations are made among the southern African taxa: S. aethiopica subsp. longiflora; S. burchellii subsp. modesta, subsp. multiflora, and subsp. pilosellifolia; S. crassifolia subsp. primuliflora; S. saldanhensis; S. rigens; and S. undulata subsp. polyantha. Each taxon is described, with information on ecology and distribution, and most species are illustrated, including SEM micrographs of the seeds.

  7. Transgenerational epigenetics: Inheritance of global cytosine methylation and methylation-related epigenetic markers in the shrub Lavandula latifolia.

    Science.gov (United States)

    Herrera, Carlos M; Alonso, Conchita; Medrano, Mónica; Pérez, Ricardo; Bazaga, Pilar

    2018-04-01

    The ecological and evolutionary significance of natural epigenetic variation (i.e., not based on DNA sequence variants) variation will depend critically on whether epigenetic states are transmitted from parents to offspring, but little is known on epigenetic inheritance in nonmodel plants. We present a quantitative analysis of transgenerational transmission of global DNA cytosine methylation (= proportion of all genomic cytosines that are methylated) and individual epigenetic markers (= methylation status of anonymous MSAP markers) in the shrub Lavandula latifolia. Methods based on parent-offspring correlations and parental variance component estimation were applied to epigenetic features of field-growing plants ('maternal parents') and greenhouse-grown progenies. Transmission of genetic markers (AFLP) was also assessed for reference. Maternal parents differed significantly in global DNA cytosine methylation (range = 21.7-36.7%). Greenhouse-grown maternal families differed significantly in global methylation, and their differences were significantly related to maternal origin. Methylation-sensitive amplified polymorphism (MSAP) markers exhibited significant transgenerational transmission, as denoted by significant maternal variance component of marker scores in greenhouse families and significant mother-offspring correlations of marker scores. Although transmission-related measurements for global methylation and MSAP markers were quantitatively lower than those for AFLP markers taken as reference, this study has revealed extensive transgenerational transmission of genome-wide global cytosine methylation and anonymous epigenetic markers in L. latifolia. Similarity of results for global cytosine methylation and epigenetic markers lends robustness to this conclusion, and stresses the value of considering both types of information in epigenetic studies of nonmodel plants. © 2018 Botanical Society of America.

  8. Documenting the Regional and local distribution of Kalmia latifolia and Rosa multiflora in West Virginia, Ohio, and Pennsylvania Forests along a soil fertility gradient

    Science.gov (United States)

    Cynthia D. Huebner; Todd Hutchinson; Todd Ristau; Alejandro Royo; James Steinman

    2012-01-01

    Use of environmental variables as predictors of vegetation distribution patterns has long been a focus of ecology. However, the effect of edaphic factors on vegetation pattern is often measured using surrogates such as topography, because accurate measures of soil fertility and nutrients are unavailable or rare (Marage and Gégout 2009). Kalmia latifolia...

  9. Strong Accumulation of Chloroplast DNA in the Y Chromosomes of Rumex acetosa and Silene latifolia

    Czech Academy of Sciences Publication Activity Database

    Šteflová, Pavlína; Hobza, Roman; Vyskot, Boris; Kejnovský, Eduard

    2014-01-01

    Roč. 142, č. 1 (2014), s. 59-65 ISSN 1424-8581 R&D Projects: GA ČR(CZ) GAP305/10/0930; GA ČR(CZ) GAP501/10/0102; GA ČR(CZ) GBP501/12/G090; GA ČR GAP501/12/2220; GA ČR(CZ) GA522/09/0083; GA MŠk(CZ) LO1204 Institutional research plan: CEZ:AV0Z50040702 Institutional support: RVO:68081707 Keywords : Chloroplast DNA * Rumex acetosa * Sex chromosomes Subject RIV: BO - Biophysics Impact factor: 1.561, year: 2014

  10. Paradoxical effects of density on measurement of copper tolerance in Silene paradoxa L.

    Science.gov (United States)

    Capuana, Maurizio; Colzi, Ilaria; Buccianti, Antonella; Coppi, Andrea; Palm, Emily; Del Bubba, Massimo; Gonnelli, Cristina

    2018-01-01

    This work investigated if the assessment of tolerance to trace metals can depend on plant density in the experimental design. A non-metallicolous and a metallicolous populations of Silene paradoxa were hydroponically cultivated at increasing density and in both the absence (-Cu conditions) and excess of copper (+Cu conditions). In -Cu conditions, the metallicolous population showed a lower susceptibility to plant density in comparison to the non-metallicolous one, explained by a higher capacity of the metallicolous population to exploit resources. In +Cu conditions, an alleviating effect of increasing density was found in roots. Such effect was present to a greater extent in the non-metallicolous population, thus making the populations equally copper-tolerant at the highest density used. In shoots, an additive effect of increasing plant density to copper toxicity was reported. Its higher intensity in the metallicolous population reverted the copper tolerance relationship at the highest plant densities used. In both populations, a density-induced decrease in root copper accumulation was observed, thus concurring to the reported mitigation in +Cu conditions. Our work revealed the importance of density studies on the optimization of eco-toxicological bioassays and of metal tolerance assessment and it can be considered the first example of an alleviating effect of increasing plant number on copper stress in a metallophyte.

  11. Anatomy and Histochemistry of Roots and Shoots in Wild Rice (Zizania latifolia Griseb.

    Directory of Open Access Journals (Sweden)

    Chaodong Yang

    2014-01-01

    Full Text Available Wild rice (Zizania latifolia Griseb. is a famous, perennial, emergent vegetable in China. The current work explores the anatomy and histochemistry of roots, stems, and leaves and the permeability of apoplastic barriers of wild rice. The adventitious roots in wild rice have suberized and lignified endodermis and adjacent, thick-walled cortical layers and suberized and lignified hypodermis, composed of a uniseriate sclerenchyma layer (SC underlying uniseriate exodermis; they also have lysigenous aerenchyma. Stems have a thickened epidermal cuticle, a narrow peripheral mechanical ring (PMR, an outer ring of vascular bundles, and an inner ring of vascular bundles embedded in a multiseriate sclerenchyma ring (SCR. There is evidence of suberin in stem SCR and PMR sclerenchyma cells. Sheathing leaves are characterized by thick cuticles and fibrous bundle sheath extensions. Air spaces in stems and leaves consist of mostly lysigenous aerenchyma and pith cavities in stems. Apoplastic barriers are found in roots and stems.

  12. Rooting and acclimatization of micropropagated marubakaido apple rootstock using Adesmia latifolia rhizobia.

    Science.gov (United States)

    Muniz, Aleksander Westphal; de Sá, Enilson Luiz; Dalagnol, Gilberto Luíz; Filho, João Américo

    2013-01-01

    In vitro rooting and the acclimatization of micropropagated rootstocks of apple trees is essential for plant development in the field. The aim of this work was to assess the use of rhizobia of Adesmia latifolia to promote rooting and acclimatization in micropropagated Marubakaido apple rootstock. An experiment involving in vitro rooting and acclimatization was performed with four strains of rhizobium and two controls, one with and the other without the addition of synthetic indoleacetic acid. The inoculated treatments involved the use of sterile inoculum and inoculum containing live rhizobia. The most significant effects on the rooting rate, primary-root length, number of roots, root length, fresh-shoot biomass, and fresh-root biomass were obtained by inoculation with strain EEL16010B and with synthetic indole acetic acid. However, there was no difference in the growth of apple explants in the acclimatization experiments. Strain EEL16010B can be used to induce in vitro rooting of the Marubakaido rootstock and can replace the use of synthetic indoleacetic acid in the rooting of this cultivar.

  13. A gravity model for the spread of a pollinator-borne plant pathogen.

    Science.gov (United States)

    Ferrari, Matthew J; Bjørnstad, Ottar N; Partain, Jessica L; Antonovics, Janis

    2006-09-01

    Many pathogens of plants are transmitted by arthropod vectors whose movement between individual hosts is influenced by foraging behavior. Insect foraging has been shown to depend on both the quality of hosts and the distances between hosts. Given the spatial distribution of host plants and individual variation in quality, vector foraging patterns may therefore produce predictable variation in exposure to pathogens. We develop a "gravity" model to describe the spatial spread of a vector-borne plant pathogen from underlying models of insect foraging in response to host quality using the pollinator-borne smut fungus Microbotryum violaceum as a case study. We fit the model to spatially explicit time series of M. violaceum transmission in replicate experimental plots of the white campion Silene latifolia. The gravity model provides a better fit than a mean field model or a model with only distance-dependent transmission. The results highlight the importance of active vector foraging in generating spatial patterns of disease incidence and for pathogen-mediated selection for floral traits.

  14. Wild food plants used in the villages of the Lake Vrana Nature Park (northern Dalmatia, Croatia

    Directory of Open Access Journals (Sweden)

    Łukasz Łuczaj

    2013-12-01

    Full Text Available Croatia is a country of diverse plant use traditions, which are still insufficiently documented. The aim of this study was to document local traditions of using wild food plants around Lake Vrana (northern Dalmatia, Zadar region.  We interviewed 43 inhabitants of six traditional villages north of Lake Vrana. On average 12 species were listed, which in total produced an inventory of 55 food plants and 3 fungi taxa. Wild vegetables were most widely collected, particularly by older women who gathered the plants mainly when herding their flocks of sheep. Wild fruits and mushrooms were rarely collected. The former used to be an important supplementary food for children, or for everyone during times of food shortage, and the latter were relatively rare due to the dry climate and shortage of woods. The most commonly collected plants are wild vegetables: Cichorium intybus, Foeniculum vulgare, Sonchus oleraceus, Asparagus acutifolius, Papaver rhoeas, Rumex pulcher, Daucus carota, Allium ampeloprasum and Silene latifolia.

  15. Point and interval estimation of pollinator importance: a study using pollination data of Silene caroliniana.

    Science.gov (United States)

    Reynolds, Richard J; Fenster, Charles B

    2008-05-01

    Pollinator importance, the product of visitation rate and pollinator effectiveness, is a descriptive parameter of the ecology and evolution of plant-pollinator interactions. Naturally, sources of its variation should be investigated, but the SE of pollinator importance has never been properly reported. Here, a Monte Carlo simulation study and a result from mathematical statistics on the variance of the product of two random variables are used to estimate the mean and confidence limits of pollinator importance for three visitor species of the wildflower, Silene caroliniana. Both methods provided similar estimates of mean pollinator importance and its interval if the sample size of the visitation and effectiveness datasets were comparatively large. These approaches allowed us to determine that bumblebee importance was significantly greater than clearwing hawkmoth, which was significantly greater than beefly. The methods could be used to statistically quantify temporal and spatial variation in pollinator importance of particular visitor species. The approaches may be extended for estimating the variance of more than two random variables. However, unless the distribution function of the resulting statistic is known, the simulation approach is preferable for calculating the parameter's confidence limits.

  16. Transgenerational plasticity in Silene vulgaris in response to three types of stress.

    Science.gov (United States)

    Sandner, T M; van Braak, J L; Matthies, D

    2018-03-23

    The environment experienced by plants can influence the phenotype of their offspring. Such transgenerational plasticity can be adaptive when it results in higher fitness of the offspring under conditions correlated with those experienced by the mother plant. However, it has rarely been tested if such anticipatory parental effects may be induced with different environments. We grew clonal replicates of Silene vulgaris under control conditions and three types of stress (nutrient deficiency, copper addition and drought), which are known from natural populations of the species. We then subjected offspring from differently treated mother plants to each of the different stress treatments to analyse the influence of maternal and offspring environment on performance and several functional traits. Current stress treatments strongly influenced biomass and functional traits of the plants, mostly in line with responses predicted by the theory of functional equilibrium. Plant performance was also influenced by maternal stress treatments, and some effects independent of initial size differences remained until harvest. In particular, stressed mothers produced offspring of higher fitness than control plants. However, there was no evidence for treatment-specific adaptive transgenerational plasticity, as offspring from a mother plant that had grown in a specific environment did not grow better in that environment than other plants. Our results indicate that the maternal environment may affect offspring traits and performance, but also that this transgenerational plasticity is not necessarily adaptive. © 2018 German Society for Plant Sciences and The Royal Botanical Society of the Netherlands.

  17. Multi-ingredients determination and fingerprint analysis of leaves from Ilex latifolia using ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry.

    Science.gov (United States)

    Fan, Chunlin; Deng, Jiewei; Yang, Yunyun; Liu, Junshan; Wang, Ying; Zhang, Xiaoqi; Fai, Kuokchiu; Zhang, Qingwen; Ye, Wencai

    2013-10-01

    An ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) method integrating multi-ingredients determination and fingerprint analysis has been established for quality assessment and control of leaves from Ilex latifolia. The method possesses the advantages of speediness, efficiency, accuracy, and allows the multi-ingredients determination and fingerprint analysis in one chromatographic run within 13min. Multi-ingredients determination was performed based on the extracted ion chromatograms of the exact pseudo-molecular ions (with a 0.01Da window), and fingerprint analysis was performed based on the base peak chromatograms, obtained by negative-ion electrospray ionization QTOF-MS. The method validation results demonstrated our developed method possessing desirable specificity, linearity, precision and accuracy. The method was utilized to analyze 22 I. latifolia samples from different origins. The quality assessment was achieved by using both similarity analysis (SA) and principal component analysis (PCA), and the results from SA were consistent with those from PCA. Our experimental results demonstrate that the strategy integrated multi-ingredients determination and fingerprint analysis using UPLC-QTOF-MS technique is a useful approach for rapid pharmaceutical analysis, with promising prospects for the differentiation of origin, the determination of authenticity, and the overall quality assessment of herbal medicines. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Analýza interakcí rodičovských genomů mezidruhového hybrida S. latifolia x S. viscosa na cytogenetické úrovni

    Czech Academy of Sciences Publication Activity Database

    Marková, Michaela

    2006-01-01

    Roč. 100, č. 5 (2006), s. 395-396 ISSN 0009-2770. [Mezioborové setkání mladých vědeckých a výzkumných pracovníků z oborů chemie, biochemie a molekulární biologie /6./. 14.06.2006-17.06.2006, Devět skal - Žďárské vrchy] R&D Projects: GA ČR(CZ) GA521/05/2076; GA ČR(CZ) GD204/05/H505 Institutional research plan: CEZ:AV0Z50040507 Keywords : interspecific hybrid * GISH * Silene Subject RIV: BO - Biophysics

  19. Evaluation of the Anti-plasmodial Activity of the Methanolic Root Extracts of Anthocleista nobilis G. Don, Nauclea latifolia Smith and Napoleona imperialis P. Beauv

    OpenAIRE

    Ijeoma H. Ogbuehi; Omotayo O. Ebong; Eme O. Asuquo; Chijioke A. Nwauche

    2014-01-01

    The emergence of resistant strains of the malaria parasite has necessitated the continued search for other effective, safe and cheap plant-based anti-malarial agents. This study was carried out to evaluate in vivo the anti-plasmodial effect of the extract of a combination of three plants as used in traditional medicine in South-east, Nigeria. Dried and ground roots of the three plants: Anthocleista nobilis, Nauclea latifolia and Napoleona imperialis were extracted in 70% methanol as a combina...

  20. Genetic variation of lodgepole pine, Pinus contorta var. latifolia, chemical and physical defenses that affect mountain pine beetle, Dendroctonus ponderosae, attack and tree mortality.

    Science.gov (United States)

    Ott, Daniel S; Yanchuk, Alvin D; Huber, Dezene P W; Wallin, Kimberly F

    2011-09-01

    Plant secondary chemistry is determined by both genetic and environmental factors, and while large intraspecific variation in secondary chemistry has been reported frequently, the levels of genetic variation of many secondary metabolites in forest trees in the context of potential resistance against pests have been rarely investigated. We examined the effect of tree genotype and environment/site on the variation in defensive secondary chemistry of lodgepole pine, Pinus contorta var. latifolia, against the fungus, Grosmannia clavigera (formerly known as Ophiostoma clavigerum), associated with the mountain pine beetle, Dendroctonus ponderosae. Terpenoids were analyzed in phloem samples from 887, 20-yr-old trees originating from 45 half-sibling families planted at two sites. Samples were collected both pre- and post-inoculation with G. clavigera. Significant variation in constitutive and induced terpenoid compounds was attributed to differences among families. The response to the challenge inoculation with G. clavigera was strong for some individual compounds, but primarily for monoterpenoids. Environment (site) also had a significant effect on the accumulation of some compounds, whereas for others, no significant environmental effect occurred. However, for a few compounds significant family x environment interactions were found. These results suggest that P. c. latifolia secondary chemistry is under strong genetic control, but the effects depend on the individual compounds and whether or not they are expressed constitutively or following induction.

  1. Diseño de un humedal para la remoción de cd, as y cr con plantas de typha latifolia (Espadaña)

    OpenAIRE

    Tejeda González, Juan Carlos

    2010-01-01

    El presente trabajo forma parte de los estudios que realizó la Facultad de Ciencias Químicas y el Posgrado Multidisciplinario de Ciencias Ambientales de la UASLP (Carranza, et al, 2005; Carranza, 2005; Alonso, 2005; Pecina, 2008; Leura, 2009) con la finalidad de estudiar la capacidad de las plantas de Typha latifolia para sobrevivir en ambientes acuáticos contaminados con metales pesados y arsénico, así como estudiar la factibilidad de utilizar a esta planta en procesos de fito...

  2. Enhancement of β-Glucan Content in the Cultivation of Cauliflower Mushroom (Sparassis latifolia) by Elicitation.

    Science.gov (United States)

    Park, Hyun; Ka, Kang-Hyeon; Ryu, Sung-Ryul

    2014-03-01

    The effectiveness of three kinds of enzymes (chitinase, β-glucuronidase, and lysing enzyme complex), employed as elicitors to enhance the β-glucan content in the sawdust-based cultivation of cauliflower mushroom (Sparassis latifolia), was examined. The elicitors were applied to the cauliflower mushroom after primordium formation, by spraying the enzyme solutions at three different levels on the sawdust-based medium. Mycelial growth was fully accomplished by the treatments, but the metabolic process during the growth of fruiting bodies was affected. The application of a lysing enzyme resulted in an increase in the β-glucan concentration by up to 31% compared to that of the control. However, the treatment resulted in a decrease in mushroom yield, which necessitated the need to evaluate its economic efficiency. Although we still need to develop a more efficient way for using elicitors to enhance functional metabolites in mushroom cultivation, the results indicate that the elicitation technique can be applied in the cultivation of medicinal/edible mushrooms.

  3. Evaluation of Compatibility between Beetle-Killed Lodgepole Pine (Pinus Contorta var. Latifolia Wood with Portland Cement

    Directory of Open Access Journals (Sweden)

    Ian D. Hartley

    2010-12-01

    Full Text Available The compatibility of wood from mountain pine beetle (Dendroctonus ponderosa killed lodgepole pine (Pinus contorta var. latifolia with Portland cement was investigated based on time-since-death as a quantitative estimator, and the presence of blue-stained sapwood, brown rot, or white rot as qualitative indicators. The exothermic behavior of cement hydration, maximum heat rate, time to reach this maximum, and total heat released within a 3.5–24 h interval were used for defining a new wood-cement compatibility index (CX. CX was developed and accounted for large discrepancies in assessing wood-cement compatibility compared to the previous methods. Using CX, no significant differences were found between fresh or beetle-killed wood with respect to the suitability for cement; except for the white rot samples which reached or exceeded the levels of incompatibility. An outstanding physicochemical behavior was also found for blue-stained sapwood and cement, producing significantly higher compatibility indices.

  4. Evaluation of Compatibility between Beetle-Killed Lodgepole Pine (Pinus Contorta var. Latifolia) Wood with Portland Cement.

    Science.gov (United States)

    Pasca, Sorin A; Hartley, Ian D; Reid, Matthew E; Thring, Ronald W

    2010-12-17

    The compatibility of wood from mountain pine beetle (Dendroctonus ponderosa) killed lodgepole pine (Pinus contorta var. latifolia) with Portland cement was investigated based on time-since-death as a quantitative estimator, and the presence of blue-stained sapwood, brown rot, or white rot as qualitative indicators. The exothermic behavior of cement hydration, maximum heat rate, time to reach this maximum, and total heat released within a 3.5-24 h interval were used for defining a new wood-cement compatibility index (CX). CX was developed and accounted for large discrepancies in assessing wood-cement compatibility compared to the previous methods. Using CX, no significant differences were found between fresh or beetle-killed wood with respect to the suitability for cement; except for the white rot samples which reached or exceeded the levels of incompatibility. An outstanding physicochemical behavior was also found for blue-stained sapwood and cement, producing significantly higher compatibility indices.

  5. Biological dosimetry after criticality accidents. Intercomparison exercise in the Silene Reactor - France; Dosimetria biologica en accidentes de criticidad. Ejercicio de intercomparacion en el Reactor Silene - Francia

    Energy Technology Data Exchange (ETDEWEB)

    Di Giorgio, Marina; Vallerga, Maria B; Taja, Maria R [Autoridad Regulatoria Nuclear, Buenos Aires (Argentina); arn gov ar, E-mail: mdigiorg@cae

    2004-07-01

    The Institute of Radiation Protection and Nuclear Safety Institute (IRSN) organized an international biological dosimetry intercomparison, at the SILENE experimental reactor (Valduc, France), simulating different criticality scenarios: bare source 4 Gy, lead shield source 1 and 2 Gy and gamma pure {sup 60}Co source 2 Gy. Fifteen laboratories were involved in this exercise, including the Argentine Biological Dosimetry Laboratory. The purposes of the intercomparison were: 1) To compare the unstable chromosome aberration (UCA) frequency observed by the different laboratories; and 2) To compare the dose estimation for gamma rays and neutrons. The objects of the present work were: I) To compare the mean frequency of UCA observed by the Argentine laboratory with the mean frequency observed by the participant laboratories as a whole. II) To compare the dose estimates performed by the Argentine lab with those estimated by the other laboratories involved in the second stage of the intercomparison. Overall, the mean frequencies of UCA and the correspondent 95% confidence limits obtained by the Argentine lab were consistent with the results obtained by the laboratories as a whole. For the gamma pure scenario, smaller variations were observed among laboratories in terms of dose (CV=18,2%) than in terms of frequency (CV=30,1%). For the mixed field scenarios, only four laboratories, including the Argentine lab, estimated gamma and neutron components of the total dose and just two (Argentine lab and lab 12) were in agreement with the given physical doses. The 1 Gy experiment presented lesser variations both in terms of frequency and dose than the other two scenarios. For the 4 and 2 Gy experiments, variations in neutron dose were more significant than variations in gamma dose, related to the magnitude of the dose. The results suggest that intercomparison exercises jointly with the accreditation of biological dosimetry by cytogenetic service laboratories, in compliance with ISO

  6. Nutrients removal by Typha latifolia and Cynodon spp. grown in constructed wetlands

    Directory of Open Access Journals (Sweden)

    Mateus Pimentel de Matos

    2011-04-01

    Full Text Available The objective of this study was to evaluate the extraction capacity of two species when grown in constructed wetlands with subsurface horizontal flow (SACs for the treatment of swine wastewater (ARS. To this end, were built 8 SACs of 2.0 m x 0.5 m x 0.6 m, fiber glass, filled with 0.55 m of fine gravels. In SAC2; SAC4; SAC6 and SAC8 was cultivated cattail (Typha latifolia and in SAC3; SAC5; SAC7 and SAC9 was cultivated tifton-85 bermudagrass (Cynodon spp.. The SAC2 and SAC3, SAC4 and SAC5, SAC6 and SAC7 and SAC8 and SAC9 received 163, 327, 461 and 561 kg ha-1 day-1 of BOD, respectively. During the 120 days of the SACs monitoring, it was found that the cattail has not adapted to the conditions of exposure. The highest yields were obtained with the application of organic load average of 327 kg ha-1 day-1 of BOD. The tifton-85 was the plant species with the highest capacity to extract nutrients, getting to draw between 443 and 540, 86 and 99, 193 and 241, 0.77 and 2.17, and 1.21 and 3.68 kg ha-1 TKN, P, K, Cu and Zn, respectively, while cattail showed greater capacity to absorb sodium.

  7. The complete chloroplast genome sequences of Lychnis wilfordii and Silene capitata and comparative analyses with other Caryophyllaceae genomes.

    Science.gov (United States)

    Kang, Jong-Soo; Lee, Byoung Yoon; Kwak, Myounghai

    2017-01-01

    The complete chloroplast genomes of Lychnis wilfordii and Silene capitata were determined and compared with ten previously reported Caryophyllaceae chloroplast genomes. The chloroplast genome sequences of L. wilfordii and S. capitata contain 152,320 bp and 150,224 bp, respectively. The gene contents and orders among 12 Caryophyllaceae species are consistent, but several microstructural changes have occurred. Expansion of the inverted repeat (IR) regions at the large single copy (LSC)/IRb and small single copy (SSC)/IR boundaries led to partial or entire gene duplications. Additionally, rearrangements of the LSC region were caused by gene inversions and/or transpositions. The 18 kb inversions, which occurred three times in different lineages of tribe Sileneae, were thought to be facilitated by the intermolecular duplicated sequences. Sequence analyses of the L. wilfordii and S. capitata genomes revealed 39 and 43 repeats, respectively, including forward, palindromic, and reverse repeats. In addition, a total of 67 and 56 simple sequence repeats were discovered in the L. wilfordii and S. capitata chloroplast genomes, respectively. Finally, we constructed phylogenetic trees of the 12 Caryophyllaceae species and two Amaranthaceae species based on 73 protein-coding genes using both maximum parsimony and likelihood methods.

  8. The relative contribution of diurnal and nocturnal pollinators to plant female fitness in a specialized nursery pollination system.

    Science.gov (United States)

    Scopece, Giovanni; Campese, Lucia; Duffy, Karl J; Cozzolino, Salvatore

    2018-02-01

    Plants involved in specialized pollinator interactions, such as nursery pollination, may experience trade-offs in their female fitness, as the larvae of their pollinators may also consume seeds produced by the flowers they pollinate. These interactions could potentially shift between mutualism and parasitism, depending on the presence and abundance of both the nursery pollinator and of other pollinators. We investigated the fitness trade-off in a Mediterranean plant ( Silene latifolia ), which has a specialist nocturnal nursery pollinator moth ( Hadena bicruris ) and is also visited by several diurnal pollinators. We estimated the pollination rates and fecundity of S. latifolia in both natural and experimental populations in the Mediterranean. We estimated natural pollination rates in different flowering times and with presence/absence of the H. bicruis moth. Then by exposing plants to each pollinator group either during the day or at night, we quantified the contribution of other diurnal pollinators and the specialized nocturnal nursery pollinator to plant female fitness. We found no difference in plant fruit set mediated by diurnal versus nocturnal pollinators, indicating that non-specialist pollinators contribute to plant female fitness. However, in both natural and experimental populations, H. bicruris was the most efficient pollinator in terms of seeds produced per fruit. These results suggest that the female fitness costs generated by nursery pollination can be overcome through higher fertilization rates relative to predation rates, even in the presence of co-pollinators. Quantifying such interactions is important for our understanding of the selective pressures that promote highly specialized mutualisms, such as nursery pollination, in the Mediterranean region, a centre of diversification of the carnation family.

  9. Transcription profiles of mitochondrial genes correlate with mitochondrial DNA haplotypes in a natural population of Silene vulgaris

    Directory of Open Access Journals (Sweden)

    Olson Matthew S

    2010-01-01

    Full Text Available Abstract Background Although rapid changes in copy number and gene order are common within plant mitochondrial genomes, associated patterns of gene transcription are underinvestigated. Previous studies have shown that the gynodioecious plant species Silene vulgaris exhibits high mitochondrial diversity and occasional paternal inheritance of mitochondrial markers. Here we address whether variation in DNA molecular markers is correlated with variation in transcription of mitochondrial genes in S. vulgaris collected from natural populations. Results We analyzed RFLP variation in two mitochondrial genes, cox1 and atp1, in offspring of ten plants from a natural population of S. vulgaris in Central Europe. We also investigated transcription profiles of the atp1 and cox1 genes. Most DNA haplotypes and transcription profiles were maternally inherited; for these, transcription profiles were associated with specific mitochondrial DNA haplotypes. One individual exhibited a pattern consistent with paternal inheritance of mitochondrial DNA; this individual exhibited a transcription profile suggestive of paternal but inconsistent with maternal inheritance. We found no associations between gender and transcript profiles. Conclusions Specific transcription profiles of mitochondrial genes were associated with specific mitochondrial DNA haplotypes in a natural population of a gynodioecious species S. vulgaris. Our findings suggest the potential for a causal association between rearrangements in the plant mt genome and transcription product variation.

  10. Manganese Silylene Hydride Complexes: Synthesis and Reactivity with Ethylene to Afford Silene Hydride Complexes.

    Science.gov (United States)

    Price, Jeffrey S; Emslie, David J H; Britten, James F

    2017-05-22

    Reaction of the ethylene hydride complex trans-[(dmpe) 2 MnH(C 2 H 4 )] (1) with Et 2 SiH 2 at 20 °C afforded the silylene hydride [(dmpe) 2 MnH(=SiEt 2 )] (2 a) as the trans-isomer. By contrast, reaction of 1 with Ph 2 SiH 2 at 60 °C afforded [(dmpe) 2 MnH(=SiPh 2 )] (2 b) as a mixture of the cis (major) and trans (minor) isomers, featuring a Mn-H-Si interaction in the former. The reaction to form 2 b also yielded [(dmpe) 2 MnH 2 (SiHPh 2 )] (3 b); [(dmpe) 2 MnH 2 (SiHR 2 )] (R=Et (3 a) and Ph (3 b)) were accessed cleanly by reaction of 2 a and 2 b with H 2 , and the analogous reactions with D 2 afforded [(dmpe) 2 MnD 2 (SiHR 2 )] exclusively. Both 2 a and 2 b engaged in unique reactivity with ethylene, generating the silene hydride complexes cis-[(dmpe) 2 MnH(R 2 Si=CHMe)] (R=Et (4 a), Ph (4 b)). Compounds trans-2 a, cis-2 b, 3 b, and 4 b were crystallographically characterized, and bonding in 2 a, 2 b, 4 a, and 4 b was probed computationally. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Efecto de precursores y reguladores de crecimiento en la formación de brotes adventicios a partir de explantes de limón persa (Citrus latifolia).

    OpenAIRE

    Pérez Luna, Adriana Isabel

    2013-01-01

    En México, la citricultura se ha visto afectada por diferentes plagas y enfermedades, ocasionando grandes daños en la producción. Limón persa (Citrus latifolia Tan.) por ser un cítrico agrio está catalogado como una especie susceptible a una de las enfermedades más devastadoras como lo es el Huanglongbing (HLB). Una alternativa viable es el desarrollo de plantas transgénicas resistentes a enfermedades. Para ello se requiere un protocolo eficiente de brotación adventicia. En este estudio se c...

  12. Lodgepole Pine Cambium (Pinus contorta Dougl. ex Loud. var. latifolia Engelm. ex S. Wats.): a springtime first peoples' food in British Columbia.

    Science.gov (United States)

    Dilbone, Megan; Turner, Nancy J; von Aderkas, Patrick

    2013-01-01

    Lodgepole pine (Pinus contorta var. latifolia) is a tree species utilized for succulent edible cambium and secondary phloem in the spring by Interior First Peoples of the Pacific Northwest. In this article we present a nutritional analysis of this food based on a pooled sample of 17 trees harvested in the Chilcotin region of British Columbia. We also present enzymatic sugar analysis of raw, dried, and cooked lodgepole pine cambium harvested from the Chilcotin and Okanagan regions in British Columbia. In the discussion we interpret the nutrient values of raw lodgepole pine cambium in comparison to dried and cooked cambium, results from other nutritional studies of pine cambium, and nutrients in some other traditional and nontraditional foods.

  13. Polymorphic Microsatellite Markers for the Tetrapolar Anther-Smut Fungus Microbotryum saponariae Based on Genome Sequencing

    Science.gov (United States)

    Fortuna, Taiadjana M.; Snirc, Alodie; Badouin, Hélène; Gouzy, Jérome; Siguenza, Sophie; Esquerre, Diane; Le Prieur, Stéphanie; Shykoff, Jacqui A.; Giraud, Tatiana

    2016-01-01

    Background Anther-smut fungi belonging to the genus Microbotryum sterilize their host plants by aborting ovaries and replacing pollen by fungal spores. Sibling Microbotryum species are highly specialized on their host plants and they have been widely used as models for studies of ecology and evolution of plant pathogenic fungi. However, most studies have focused, so far, on M. lychnidis-dioicae that parasitizes the white campion Silene latifolia. Microbotryum saponariae, parasitizing mainly Saponaria officinalis, is an interesting anther-smut fungus, since it belongs to a tetrapolar lineage (i.e., with two independently segregating mating-type loci), while most of the anther-smut Microbotryum fungi are bipolar (i.e., with a single mating-type locus). Saponaria officinalis is a widespread long-lived perennial plant species with multiple flowering stems, which makes its anther-smut pathogen a good model for studying phylogeography and within-host multiple infections. Principal Findings Here, based on a generated genome sequence of M. saponariae we developed 6 multiplexes with a total of 22 polymorphic microsatellite markers using an inexpensive and efficient method. We scored these markers in fungal individuals collected from 97 populations across Europe, and found that the number of their alleles ranged from 2 to 11, and their expected heterozygosity from 0.01 to 0.58. Cross-species amplification was examined using nine other Microbotryum species parasitizing hosts belonging to Silene, Dianthus and Knautia genera. All loci were successfully amplified in at least two other Microbotryum species. Significance These newly developed markers will provide insights into the population genetic structure and the occurrence of within-host multiple infections of M. saponariae. In addition, the draft genome of M. saponariae, as well as one of the described markers will be useful resources for studying the evolution of the breeding systems in the genus Microbotryum and the

  14. Neutron Activation and Thermoluminescent Detector Responses to a Bare Pulse of the CEA Valduc SILENE Critical Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Thomas Martin [ORNL; Isbell, Kimberly McMahan [ORNL; Lee, Yi-kang [French Atomic Energy Commission (CEA), Centre de Saclay, Gif sur Yvette; Gagnier, Emmanuel [French Atomic Energy Commission (CEA), Centre de Saclay, Gif sur Yvette; Authier, Nicolas [French Atomic Energy Commission (CEA), Centre de Valduc, Is-sur-Tille; Piot, Jerome [French Atomic Energy Commission (CEA), Centre de Valduc, Is-sur-Tille; Jacquet, Xavier [French Atomic Energy Commission (CEA), Centre de Valduc, Is-sur-Tille; Rousseau, Guillaume [French Atomic Energy Commission (CEA), Centre de Valduc, Is-sur-Tille; Reynolds, Kevin H. [Y-12 National Security Complex

    2016-09-01

    This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 11, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). The goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.

  15. Biological dosimetry after criticality accidents. Intercomparison exercise in the Silene Reactor - France

    International Nuclear Information System (INIS)

    Di Giorgio, Marina; Vallerga, Maria B.; Taja, Maria R.

    2004-01-01

    The Institute of Radiation Protection and Nuclear Safety Institute (IRSN) organized an international biological dosimetry intercomparison, at the SILENE experimental reactor (Valduc, France), simulating different criticality scenarios: bare source 4 Gy, lead shield source 1 and 2 Gy and gamma pure 60 Co source 2 Gy. Fifteen laboratories were involved in this exercise, including the Argentine Biological Dosimetry Laboratory. The purposes of the intercomparison were: 1) To compare the unstable chromosome aberration (UCA) frequency observed by the different laboratories; and 2) To compare the dose estimation for gamma rays and neutrons. The objects of the present work were: I) To compare the mean frequency of UCA observed by the Argentine laboratory with the mean frequency observed by the participant laboratories as a whole. II) To compare the dose estimates performed by the Argentine lab with those estimated by the other laboratories involved in the second stage of the intercomparison. Overall, the mean frequencies of UCA and the correspondent 95% confidence limits obtained by the Argentine lab were consistent with the results obtained by the laboratories as a whole. For the gamma pure scenario, smaller variations were observed among laboratories in terms of dose (CV=18,2%) than in terms of frequency (CV=30,1%). For the mixed field scenarios, only four laboratories, including the Argentine lab, estimated gamma and neutron components of the total dose and just two (Argentine lab and lab 12) were in agreement with the given physical doses. The 1 Gy experiment presented lesser variations both in terms of frequency and dose than the other two scenarios. For the 4 and 2 Gy experiments, variations in neutron dose were more significant than variations in gamma dose, related to the magnitude of the dose. The results suggest that intercomparison exercises jointly with the accreditation of biological dosimetry by cytogenetic service laboratories, in compliance with ISO

  16. How to be an attractive male: floral dimorphism and attractiveness to pollinators in a dioecious plant

    Directory of Open Access Journals (Sweden)

    Waelti Marc O

    2009-08-01

    Full Text Available Abstract Background Sexual selection theory predicts that males are limited in their reproductive success by access to mates, whereas females are more limited by resources. In animal-pollinated plants, attraction of pollinators and successful pollination is crucial for reproductive success. In dioecious plant species, males should thus be selected to increase their attractiveness to pollinators by investing more than females in floral traits that enhance pollinator visitation. We tested the prediction of higher attractiveness of male flowers in the dioecious, moth-pollinated herb Silene latifolia, by investigating floral signals (floral display and fragrance and conducting behavioral experiments with the pollinator-moth, Hadena bicruris. Results As found in previous studies, male plants produced more but smaller flowers. Male flowers, however, emitted significantly larger amounts of scent than female flowers, especially of the pollinator-attracting compounds. In behavioral tests we showed that naïve pollinator-moths preferred male over female flowers, but this preference was only significant for male moths. Conclusion Our data suggest the evolution of dimorphic floral signals is shaped by sexual selection and pollinator preferences, causing sexual conflict in both plants and pollinators.

  17. Impacts of the physiochemical properties of chlorinated solvents on the sorption of trichloroethylene to the roots of Typha latifolia

    Energy Technology Data Exchange (ETDEWEB)

    Ma Xingmao [Department of Civil and Environmental Engineering, Southern Illinois University Carbondale, 1230 Lincoln Drive, Carbondale, IL 62901 (United States)], E-mail: ma@engr.siu.edu; Wang Chen [Department of Civil and Environmental Engineering, Southern Illinois University Carbondale, 1230 Lincoln Drive, Carbondale, IL 62901 (United States)

    2009-03-15

    Sorption to plant roots is the first step for organic contaminants to enter plant tissues. Mounting evidence is showing that sorption to plant roots is nonlinear and competitive. The objective of this study was to investigate the effects of physiochemical properties of homologous chlorinated ethenes and ethanes on the competitive sorption of trichloroethylene (TCE) to the roots of Typha latifolia (cattail). The results showed that chlorinated ethenes exerted significantly stronger competition on the sorption of TCE than chlorinated ethanes. Individual physiochemical properties of organic compounds could be related to the competitive capacity of chlorinated ethenes, but the roles appeared secondary, with molecular structures showing primary effects. Based on these observations, a two-step sorption mechanism was proposed, consisting of the interactions between organic compounds and functional groups on the root surface and subsequent pore filling and absorption to the hydrophobic domains in the composition of roots. - Molecular structures and physiochemical properties of homologous chlorinated aliphatics are important factors affecting competitive sorption of TCE to plant roots.

  18. Impacts of the physiochemical properties of chlorinated solvents on the sorption of trichloroethylene to the roots of Typha latifolia

    International Nuclear Information System (INIS)

    Ma Xingmao; Wang Chen

    2009-01-01

    Sorption to plant roots is the first step for organic contaminants to enter plant tissues. Mounting evidence is showing that sorption to plant roots is nonlinear and competitive. The objective of this study was to investigate the effects of physiochemical properties of homologous chlorinated ethenes and ethanes on the competitive sorption of trichloroethylene (TCE) to the roots of Typha latifolia (cattail). The results showed that chlorinated ethenes exerted significantly stronger competition on the sorption of TCE than chlorinated ethanes. Individual physiochemical properties of organic compounds could be related to the competitive capacity of chlorinated ethenes, but the roles appeared secondary, with molecular structures showing primary effects. Based on these observations, a two-step sorption mechanism was proposed, consisting of the interactions between organic compounds and functional groups on the root surface and subsequent pore filling and absorption to the hydrophobic domains in the composition of roots. - Molecular structures and physiochemical properties of homologous chlorinated aliphatics are important factors affecting competitive sorption of TCE to plant roots

  19. Comparative study of bio-ethanol production from mahula (Madhuca latifolia L.) flowers by Saccharomyces cerevisiae and Zymomonas mobilis

    Energy Technology Data Exchange (ETDEWEB)

    Behera, Shuvashish; Mohanty, Rama Chandra [Department of Botany, Utkal University, Vanivihar, Bhubaneswar 751004, Orissa (India); Ray, Ramesh Chandra [Microbiology Laboratory, Central Tuber Crops Research Institute (Regional Centre), Bhubaneswar 751019, Orissa (India)

    2010-07-15

    Mahula (Madhuca latifolia L.) flower is a suitable alternative cheaper carbohydrate source for production of bio-ethanol. Recent production of bio-ethanol by microbial fermentation as an alternative energy source has renewed research interest because of the increase in the fuel price. Saccharomyces cerevisiae (yeast) and Zymomonas mobilis (bacteria) are two most widely used microorganisms for ethanol production. In this study, experiments were carried out to compare the potential of the yeast S. cerevisiae (CTCRI strain) with the bacterium Z. mobilis (MTCC 92) for ethanol fermentation from mahula flowers. The ethanol production after 96 h fermentation was 149 and 122.9 g kg{sup -1} flowers using free cells of S. cerevisiae and Z. mobilis, respectively. The S. cerevisiae strain showed 21.2% more final ethanol production in comparison to Z. mobilis. Ethanol yield (Yx/s), volumetric product productivity (Qp), sugar to ethanol conversion rate (%) and microbial biomass concentration (X) obtained by S. cerevisiae were found to be 5.2%, 21.1%, 5.27% and 134% higher than Z. mobilis, respectively after 96 h of fermentation. (author)

  20. Comparative study of bio-ethanol production from mahula (Madhuca latifolia L.) flowers by Saccharomyces cerevisiae and Zymomonas mobilis

    International Nuclear Information System (INIS)

    Behera, Shuvashish; Mohanty, Rama Chandra; Ray, Ramesh Chandra

    2010-01-01

    Mahula (Madhuca latifolia L.) flower is a suitable alternative cheaper carbohydrate source for production of bio-ethanol. Recent production of bio-ethanol by microbial fermentation as an alternative energy source has renewed research interest because of the increase in the fuel price. Saccharomyces cerevisiae (yeast) and Zymomonas mobilis (bacteria) are two most widely used microorganisms for ethanol production. In this study, experiments were carried out to compare the potential of the yeast S. cerevisiae (CTCRI strain) with the bacterium Z. mobilis (MTCC 92) for ethanol fermentation from mahula flowers. The ethanol production after 96 h fermentation was 149 and 122.9 g kg -1 flowers using free cells of S. cerevisiae and Z. mobilis, respectively. The S. cerevisiae strain showed 21.2% more final ethanol production in comparison to Z. mobilis. Ethanol yield (Yx/s), volumetric product productivity (Qp), sugar to ethanol conversion rate (%) and microbial biomass concentration (X) obtained by S. cerevisiae were found to be 5.2%, 21.1%, 5.27% and 134% higher than Z. mobilis, respectively after 96 h of fermentation. (author)

  1. Transcriptome and biochemical analysis of a flower color polymorphism in Silene littorea (Caryophyllaceae

    Directory of Open Access Journals (Sweden)

    Inés eCasimiro-Soriguer

    2016-02-01

    Full Text Available Flower color polymorphisms are widely used as model traits from genetics to ecology, yet determining the biochemical and molecular basis can be challenging. Anthocyanin-based flower color variations can be caused by at least 12 structural and three regulatory genes in the anthocyanin biosynthetic pathway. We use mRNA-Seq to simultaneously sequence and estimate expression of these candidate genes in nine samples of Silene littorea representing three color morphs (dark pink, light pink and white across three developmental stages in hopes of identifying the cause of flower color variation. We identified 29 putative paralogues for the 15 candidate genes in the anthocyanin biosynthetic pathway. We assembled complete coding sequences for 16 structural loci and nine of ten regulatory loci. Among these 29 putative paralogues, we identified 622 SNPs, yet only nine synonymous SNPs in Ans had allele frequencies that differentiated pigmented petals (dark pink and light pink from white petals. These Ans allele frequency differences were further investigated with an expanded sequencing survey of 38 individuals, yet no SNPs consistently differentiated the color morphs. We also found one locus, F3h1, with strong differential expression between pigmented and white samples (>42x. This may be caused by decreased expression of Myb1a in white petal buds. Myb1a in S. littorea is a regulatory locus closely related to Subgroup 7 Mybs known to regulate F3h and other loci in the first half of the ABP in model species. We then compare the mRNA-Seq results with petal biochemistry which revealed cyanidin as the primary anthocyanin and five flavonoid intermediates. Concentrations of three of the flavonoid intermediates were significantly lower in white petals than in pigmented petals (rutin, quercetin and isovitexin. The biochemistry results for rutin, quercetin, luteolin and apigenin are consistent with the transcriptome results suggesting a blockage at F3h, possibly caused

  2. Uptake and metabolism of diclofenac in Typha latifolia--how plants cope with human pharmaceutical pollution.

    Science.gov (United States)

    Bartha, Bernadett; Huber, Christian; Schröder, Peter

    2014-10-01

    The fate of pharmaceuticals in our environment is a very important issue for environmental and health research. Although these substances have been detected in environmental compartments in low concentration until now, they will pose considerable environmental risk to ecosystems, animals and human due to their biological activity. Alternative plant based removal technologies that make use of some potential wetland species like Phragmites or Typha within traditional wastewater treatment plants have to be established to cope with this "new generation" of pollutants. We investigated uptake and translocation of diclofenac (1mgl(-1)) in the macrophyte Typha latifolia L. during one week exposure in greenhouse experiments. Detoxification products and involved key enzymatic processes were identified. We also examined the oxidative stress induced by the treatment and the defense capacity of the plants. Rapid uptake and effective metabolism were observed, where glycoside and glutathione conjugates represent dominant metabolites. Up to seven-fold induction of glycosyltransferase activity was observed in roots, but not in shoots. Glutathione S-transferase activity was also induced, but to a lower extent. The activity changes of defense enzymes points to oxidative stress in the plants. Our results show that human pharmaceuticals can be metabolized by plants similar to xenobiotics, but that similarities to human metabolism are limited. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  3. MK17, a specific marker closely linked to the gynoecium suppression region on the Y chromosome in Silene latifolia

    Czech Academy of Sciences Publication Activity Database

    Hobza, Roman; Hrušáková, P.; Šafář, Jan; Bartoš, Jan; Janoušek, Bohuslav; Žlůvová, Jitka; Michu, Elleni; Doležel, Jaroslav; Vyskot, Boris

    2006-01-01

    Roč. 113, č. 2 (2006), s. 280-287 ISSN 0040-5752 R&D Projects: GA ČR(CZ) GA521/06/0056; GA ČR(CZ) GD204/05/H505; GA ČR(CZ) GA521/05/2076; GA AV ČR(CZ) 1QS500040507 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50380511 Keywords : sex chromosomes * melandrium-album * evolution Subject RIV: BO - Biophysics Impact factor: 2.715, year: 2006

  4. Evaluation of Anti-Inflammatory Activity of Citrus latifolia Tanaka Essential Oil and Limonene in Experimental Mouse Models

    Directory of Open Access Journals (Sweden)

    Raquel Kummer

    2013-01-01

    Full Text Available The genus Citrus (Rutaceae includes several species of plants that produce some of the most cultivated fruits in the world, providing an appreciable content of essential oil. In folk medicine, they are used as a cholagogue, antipyretic, anti-inflammatory, sedative, and antitoxic effects. Lemon essential oil has been used since ancient times for its antiseptic, carminative, diuretic, and eupeptic effects. In this study, we investigated the anti-inflammatory activity of Citrus latifolia Tanaka essential oil (CLEO and its main constituent LIM. In the cell viability assay, CLEO and LIM (3, 10, 30, and 90 μg/mL had low cytotoxicity. In zymosan-induced peritonitis, LIM (500 mg/kg decreased the infiltration of peritoneal exudate leukocytes and decreased the number of polymorphonuclear leukocytes. In vitro chemotaxis revealed that CLEO and LIM (1, 3, and 10 µg/mL promoted a significant reduction of neutrophil migration toward fMLP and LTB4. LIM (500 mg/kg also reduced TNF-α levels but did not alter IL-10 levels in the peritoneal exudate. In conclusion, this study showed that LIM isolated from CLEO had potential anti-inflammatory effects, likely by inhibiting proinflammatory mediators present in inflammatory exudate and leukocyte chemotaxis.

  5. Origin of C. latifolia and C. aurantiifolia triploid limes: the preferential disomic inheritance of doubled-diploid 'Mexican' lime is consistent with an interploid hybridization hypothesis.

    Science.gov (United States)

    Rouiss, H; Bakry, F; Froelicher, Y; Navarro, L; Aleza, P; Ollitrault, P

    2018-03-05

    Two main types of triploid limes are produced worldwide. The 'Tahiti' lime type (Citrus latifolia) is predominant, while the 'Tanepao' type (C. aurantiifolia) is produced to a lesser extent. Both types result from natural interspecific hybridization involving a diploid gamete of C. aurantiifolia 'Mexican' lime type (itself a direct interspecific C. micrantha × C. medica hybrid). The meiotic behaviour of a doubled-diploid 'Mexican' lime, the interspecific micrantha/medica recombination and the resulting diploid gamete structures were analysed to investigate the possibility that 'Tahiti' and 'Tanepao' varieties are derived from natural interploid hybridization. A population of 85 tetraploid hybrids was established between a doubled-diploid clementine and a doubled-diploid 'Mexican' lime and used to infer the genotypes of 'Mexican' lime diploid gametes. Meiotic behaviour was studied through combined segregation analysis of 35 simple sequenbce repeat (SSR) and single nucleotide polymorphismn (SNP) markers covering the nine citrus chromosomes and cytogenetic studies. It was supplemented by pollen viability assessment. Pollen viability of the doubled-diploid Mexican lime (64 %) was much higher than that of the diploid. On average, 65 % of the chromosomes paired as bivalents and 31.4 % as tetravalents. Parental heterozygosity restitution ranged from 83 to 99 %. Disomic inheritance with high preferential pairing values was deduced for three chromosomes. Intermediate inheritances, with disomic trend, were found for five chromosomes, and an intermediate inheritance was observed for one chromosome. The average effective interspecific recombination rate was low (1.2 cM Mb-1). The doubled-diploid 'Mexican' lime had predominantly disomic segregation, producing interspecific diploid gamete structures with high C. medica/C. micrantha heterozygosity, compatible with the phylogenomic structures of triploid C. latifolia and C. aurantiifolia varieties. This disomic trend limits

  6. Effect of genotype, Cr(III and Cr(VI on plant growth and micronutrient status in Silene vulgaris (Moench

    Directory of Open Access Journals (Sweden)

    A. E. Pradas-del-Real

    2013-06-01

    Full Text Available Chromium released into the environment from industrial activities has become an important environmental concern. Silene vulgaris has been proven to be tolerant to many heavy metals, so it is considered an interesting species in the revegetation and restoration of polluted soils, but no information is available about its response to Cr. The objective of this work was to study uptake and influence on plant growth of Cr(III and Cr(VI in six genotypes (four hermaphrodites and two females of S. vulgaris from different sites of Madrid (Spain. Plants were treated for 12 days with 60 µM of Cr(III or Cr(VI in semihydroponics. Dry weights, soil-plant analysis development values (SPAD reading with chlorophylls and micronutrient and total Cr concentrations were determined. Metal uptake was higher in presence of Cr(VI than of Cr(III and poorly translocated to the shoots. In both cases S. vulgaris did not show visual toxicity symptoms, biomass reduction, or differences among SPAD values as consequence of Cr additions. However genotypes SV36 and SV38 showed Fe and Mn imbalance. This is the first report on the relatively good performance of hermaphrodite and female S. vulgaris genotypes in Cr uptake and physiological traits, but further studies will be necessary to elucidate the mechanisms by which the gender may influence these variables. S. vulgaris presented high diversity at genotypic level; the treatment with hexavalent Cr increased the differences among genotypes so the use of cuttings from an homogeneous genotype seems to be an adequate method for the study of this species.

  7. Criticality accidents in solution (CRAC and SILENE programmes) and complementary studies of accidents; radiation dosimetry in human organism during the CRAC programme

    International Nuclear Information System (INIS)

    Barbry, M.; Dousset, M.

    C.R.A.C. (CRiticality occurring ACcidentally) programme is intended to study experimentally the development of a criticality accident as it could occur when handling solutions of fissile material as well as the radiological consequences of such an accident. The fissile matter solutions have been chosen (a) for practical considerations of use and (b) because the probability of an accident occurring seems greater with this type of environment, as the known accidents have shown. The programme is twofold: study of accident physics: form of the evolution (peak, plateau, oscillations, boil up of solutions) the most probable maximum power, minimal power, flux and radiation spectra emitted, freed energy, associated effects, radiolysis, constraints, etc., study of radiological consequences: area dosimetry, individual dosimetry, radiobiological studies, etc. Additional criticality Accident experiments have been and continue to be made on the SILENE reactor in the following principal domains: determination of the emission rate of gaseous fission products and aerosols, area dosimetry and health dosimetry in the presence of shields around the core to vary the neutron and gamma components of the radiation field. Improvement in the knowledge of certain particular aspects of the power excursion, radiolysis gas and pressure wave, experiments of the ''boiling'' type [fr

  8. The alpine cushion plant Silene acaulis as foundation species: a bug's-eye view to facilitation and microclimate.

    Directory of Open Access Journals (Sweden)

    Olivia Molenda

    Full Text Available Alpine ecosystems are important globally with high levels of endemic and rare species. Given that they will be highly impacted by climate change, understanding biotic factors that maintain diversity is critical. Silene acaulis is a common alpine nurse plant shown to positively influence the diversity and abundance of organisms--predominantly other plant species. The hypothesis that cushion or nurse plants in general are important to multiple trophic levels has been proposed but rarely tested. Alpine arthropod diversity is also largely understudied worldwide, and the plant-arthropod interactions reported are mostly negative, that is,. herbivory. Plant and arthropod diversity and abundance were sampled on S. acaulis and at paired adjacent microsites with other non-cushion forming vegetation present on Whistler Mountain, B.C., Canada to examine the relative trophic effects of cushion plants. Plant species richness and abundance but not Simpson's diversity index was higher on cushion microsites relative to other vegetation. Arthropod richness, abundance, and diversity were all higher on cushion microsites relative to other vegetated sites. On a microclimatic scale, S. acaulis ameliorated stressful conditions for plants and invertebrates living inside it, but the highest levels of arthropod diversity were observed on cushions with tall plant growth. Hence, alpine cushion plants can be foundation species not only for other plant species but other trophic levels, and these impacts are expressed through both direct and indirect effects associated with altered environmental conditions and localized productivity. Whilst this case study tests a limited subset of the membership of alpine animal communities, it clearly demonstrates that cushion-forming plant species are an important consideration in understanding resilience to global changes for many organisms in addition to other plants.

  9. Preliminary Screening of Antioxidant and Antibacterial Activities and Establishment of an Efficient Callus Induction in Curculigo latifolia Dryand (Lemba

    Directory of Open Access Journals (Sweden)

    Reza Farzinebrahimi

    2016-01-01

    Full Text Available Leaf, seed, and tuber explants of C. latifolia were inoculated on MS medium supplemented with various concentrations of BAP and IBA, alone or in combinations, to achieve in vitro plant regeneration. Subsequently, antioxidant and antibacterial activities were determined from in vitro and in vivo plant developed. No response was observed from seed culture on MS media with various concentrations of PGRs. The highest percentage of callus was observed on tuber explants (94% and leaf explants (89% when cultured on MS media supplemented with IBA in combination with BAP. A maximum of 88% shoots per tuber explant, with a mean number of shoots (8.8±1.0, were obtained on MS medium supplemented with combinations of BAP and IBA (2.5 mg L−1. The best root induction (92% and mean number (7.6±0.5 from tuber explants were recorded on 2.5 mg L−1 IBA alone supplemented to MS medium. The higher antioxidant content (80% was observed from in vivo tuber. However, tuber part from the intact plant showed higher inhibition zone in antibacterial activity compared to other in vitro and in vivo tested parts.

  10. CRECIMIENTO Y DESARROLLO DE LA LIMA ÁCIDA (Citrus latifolia Tanaka, cv. Tahití, EN SUELOS CON LIMITACIONES POR PROFUNDIDAD EFECTIVA, EN UN BOSQUE SECO TROPICAL GROWTH AND DEVELOPMENT OF LIME (Citrus latifolia Tanaka, cv. Tahiti, IN SOILS WITH LIMITATIONS BY EFFECTIVE DEPTH IN A TROPICAL DRY FOREST

    Directory of Open Access Journals (Sweden)

    Gabriel Fernando Ochoa Agudelo

    2012-06-01

    Full Text Available Resumen. Se evaluó la evolución de la biomasa, la distribución diferencial de ésta entre los órganos y algunos parámetros del crecimiento y desarrollo, de la lima ácida (Citrus latifolia Tanaka, cv. Tahití, injertada sobre Carrizo y Kryder. El cultivo se estableció en suelos con limitaciones por profundidad efectiva (PE entre 10 y 20 cm; las evaluaciones se realizaron a los 24, 32 y 39 meses después del trasplante. Se debe tener presente que el crecimiento de las raíces está condicionado a los atributos edáficos en donde se establecen los cultivos, en especial los perennes, en cuyo caso existen requerimientos mínimos de PE para el adecuado desarrollo de los árboles; se establecieron diferencias entre la biomasa acumulada, como consecuencia de ésta limitación. Al comparar el crecimiento de las plantas con la PE se evidenció que los individuos que crecieron en suelos con PE de 20 cm, presentaron un desarrollo relativamente semejante a plantaciones sin limitaciones de este tipo; mientras que, en suelos con PE inferior a 10 cm, la respuesta fue 3 a 5 veces menor.Abstract. It was evaluated the evolution of biomass, its differential distribution among the organs and some parameters of growth and development of acid lime (Citrus latifolia Tanaka, cv. Tahiti, grafted on Carrizo and Kryder patterns. The plants were established in soils with limitations by its effective depth (ED, which ranged between 10 and 20 cm. Assessments were effectuated at 24, 32 and 39 months after transplantation. It is must to keep in mind that root growth is conditioned to the soil attributes of the site where the crops are established, especially in the case of perennials, which have requirements of minimum PE in order to achieve an adequate development. Differences were established between biomass accumulated as a result of the limitation in effective depth. When comparing the growth of plants with ED, we found that the individuals that grew up in soils with

  11. An accumulation of tandem DNA repeats on the Y chromosome in Silene latifolia during early stages of sex chromosome evolution

    Czech Academy of Sciences Publication Activity Database

    Hobza, Roman; Lengerová, Martina; Svoboda, J.; Kubeková, H.; Kejnovský, Eduard; Vyskot, Boris

    2006-01-01

    Roč. 115, č. 5 (2006), s. 376-382 ISSN 0009-5915 R&D Projects: GA ČR(CZ) GA521/06/0056; GA ČR(CZ) GA204/05/2097 Institutional research plan: CEZ:AV0Z50040507 Keywords : plant melandrium-album * dioecious plant * X-chromosome Subject RIV: BO - Biophysics Impact factor: 4.065, year: 2006

  12. Improving niche projections of plant species under climate change: Silene acaulis on the British Isles as a case study

    Science.gov (United States)

    Ferrarini, Alessandro; Alsafran, Mohammed H. S. A.; Dai, Junhu; Alatalo, Juha M.

    2018-04-01

    Empirical works to assist in choosing climatically relevant variables in the attempt to predict climate change impacts on plant species are limited. Further uncertainties arise in choice of an appropriate niche model. In this study we devised and tested a sharp methodological framework, based on stringent variable ranking and filtering and flexible model selection, to minimize uncertainty in both niche modelling and successive projection of plant species distributions. We used our approach to develop an accurate, parsimonious model of Silene acaulis (L.) presence/absence on the British Isles and to project its presence/absence under climate change. The approach suggests the importance of (a) defining a reduced set of climate variables, actually relevant to species presence/absence, from an extensive list of climate predictors, and (b) considering climate extremes instead of, or together with, climate averages in projections of plant species presence/absence under future climate scenarios. Our methodological approach reduced the number of relevant climate predictors by 95.23% (from 84 to only 4), while simultaneously achieving high cross-validated accuracy (97.84%) confirming enhanced model performance. Projections produced under different climate scenarios suggest that S. acaulis will likely face climate-driven fast decline in suitable areas on the British Isles, and that upward and northward shifts to occupy new climatically suitable areas are improbable in the future. Our results also imply that conservation measures for S. acaulis based upon assisted colonization are unlikely to succeed on the British Isles due to the absence of climatically suitable habitat, so different conservation actions (seed banks and/or botanical gardens) are needed.

  13. Neutron Activation Foil and Thermoluminescent Dosimeter Responses to a Lead Reflected Pulse of the CEA Valduc SILENE Critical Assembly

    International Nuclear Information System (INIS)

    Miller, Thomas Martin; Celik, Cihangir; Isbell, Kimberly McMahan; Lee, Yi-kang; Gagnier, Emmanuel; Authier, Nicolas; Piot, Jerome; Jacquet, Xavier; Rousseau, Guillaume; Reynolds, Kevin H.

    2016-01-01

    This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 13, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). The goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. The CIDAS detects gammas with a Geiger-Muller tube, and the Rocky Flats detects neutrons via charged particles produced in a thin 6 LiF disc, depositing energy in a Si solid-state detector. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.

  14. Neutron Activation Foil and Thermoluminescent Dosimeter Responses to a Polyethylene Reflected Pulse of the CEA Valduc SILENE Critical Assembly

    International Nuclear Information System (INIS)

    Miller, Thomas Martin; Celik, Cihangir; McMahan, Kimberly L.; Lee, Yi-kang; Gagnier, Emmanuel; Authier, Nicolas

    2016-01-01

    This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 19, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). The goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. The CIDAS detects gammas with a Geiger-Muller tube and the Rocky Flats detects neutrons via charged particles produced in a thin "6LiF disc depositing energy in a Si solid state detector. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.

  15. Neutron Activation Foil and Thermoluminescent Dosimeter Responses to a Polyethylene Reflected Pulse of the CEA Valduc SILENE Critical Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Thomas Martin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Celik, Cihangir [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); McMahan, Kimberly L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lee, Yi-kang [French Atomic Energy Commission (CEA), Saclay (France); Gagnier, Emmanuel [French Atomic Energy Commission (CEA), Centre de Saclay, Gif sur Yvette; Authier, Nicolas [French Atomic Energy Commission (CEA), Salives (France). Valduc Centre for Nuclear Studies; Piot, Jerome [French Atomic Energy Commission (CEA), Salives (France). Valduc Centre for Nuclear Studies; Jacquet, Xavier [French Atomic Energy Commission (CEA), Salives (France). Valduc Centre for Nuclear Studies; Rousseau, Guillaume [French Atomic Energy Commission (CEA), Salives (France). Valduc Centre for Nuclear Studies; Reynolds, Kevin H. [Y-12 National Security Complex, Oak Ridge, TN (United States)

    2016-09-01

    This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 19, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). The goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. The CIDAS detects gammas with a Geiger-Muller tube and the Rocky Flats detects neutrons via charged particles produced in a thin 6LiF disc depositing energy in a Si solid state detector. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.

  16. Neutron Activation Foil and Thermoluminescent Dosimeter Responses to a Lead Reflected Pulse of the CEA Valduc SILENE Critical Assembly

    Energy Technology Data Exchange (ETDEWEB)

    Miller, Thomas Martin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Celik, Cihangir [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Isbell, Kimberly McMahan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lee, Yi-kang [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Gagnier, Emmanuel [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Authier, Nicolas [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Piot, Jerome [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Jacquet, Xavier [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Rousseau, Guillaume [Commissariat a l' Energie Atomique et aux Energies Alternatives (CEA-Saclay), Gif-sur-Yvette (France); Reynolds, Kevin H. [Y-12 National Security Complex, Oak Ridge, TN (United States)

    2016-09-01

    This benchmark experiment was conducted as a joint venture between the US Department of Energy (DOE) and the French Commissariat à l'Energie Atomique (CEA). Staff at the Oak Ridge National Laboratory (ORNL) in the US and the Centre de Valduc in France planned this experiment. The experiment was conducted on October 13, 2010 in the SILENE critical assembly facility at Valduc. Several other organizations contributed to this experiment and the subsequent evaluation, including CEA Saclay, Lawrence Livermore National Laboratory (LLNL), the Y-12 National Security Complex (NSC), Babcock International Group in the United Kingdom, and Los Alamos National Laboratory (LANL). The goal of this experiment was to measure neutron activation and thermoluminescent dosimeter (TLD) doses from a source similar to a fissile solution critical excursion. The resulting benchmark can be used for validation of computer codes and nuclear data libraries as required when performing analysis of criticality accident alarm systems (CAASs). A secondary goal of this experiment was to qualitatively test performance of two CAAS detectors similar to those currently and formerly in use in some US DOE facilities. The detectors tested were the CIDAS MkX and the Rocky Flats NCD-91. The CIDAS detects gammas with a Geiger-Muller tube, and the Rocky Flats detects neutrons via charged particles produced in a thin 6LiF disc, depositing energy in a Si solid-state detector. These detectors were being evaluated to determine whether they would alarm, so they were not expected to generate benchmark quality data.

  17. Phytoremediation of biosolids from an end-of-life municipal lagoon using cattail (Typha latifolia L.) and switchgrass (Panicum virgatum L.).

    Science.gov (United States)

    Jeke, Nicholson N; Hassan, Adenike O; Zvomuya, Francis

    2017-03-04

    Land spreading of biosolids as a disposal option is expensive and can disperse pathogens and contaminants in the environment. This growth room study examined phytoremediation using switchgrass (Panicum virgatum L.) and cattail (Typha latifolia L.) as an alternative to land spreading of biosolids. Seedlings were transplanted into pots containing 3.9 kg of biosolids (dry wt.). Aboveground biomass (AGB) was harvested either once or twice during each 90-day growth period. Switchgrass AGB yield was greater with two harvests than with one harvest during the first 90-day growth period, whereas cattail yield was not affected by harvest frequency. In the second growth period, harvesting frequency did not affect the yield of either plant species. However, repeated harvesting significantly improved nitrogen (N) and phosphorus (P) uptake by both plants in the first period. Phytoextraction of P was significantly greater for switchgrass (3.9% of initial biosolids P content) than for cattail (2.8%), while plant species did not have a significant effect on N phytoextraction. The trace element accumulation in the AGB of both plant species was negligible. Phytoextraction rates attained in this study suggest that phytoremediation can effectively remove P from biosolids and offers a potentially viable alternative to the disposal of biosolids on agricultural land.

  18. Effect of irrigation and fertilization on crop yield and fruit quality of the Tahiti lime Citrus latifolia Tanaka (Rutaceae

    Directory of Open Access Journals (Sweden)

    Diana Dorado Guerra

    2015-01-01

    Full Text Available In a seven years old citrus grove of Tahiti lime Citrus latifolia Tanaka (Rutaceae located in El Espinal, Tolima, Colombia, which has a predominantly negative water balance throughout the year, we evaluated the effect of irrigation and fertilization on yield and fruit quality in 2009 and 2011. Trees were subjected to three levels of water based on the evapotranspiration reference (ETo: L1=100 %, L2=70 % and L3=50 %. We applied three nitrogen treatments: N1=nitrogen required by the nutritional balance, N2=twice the level of nitrogen used in N1, and N3=fertilizer application used by the common farmer. We evaluated the performance, fruit weight, polar and equatorial diameter of fruit, shell thickness, weight and percentage of juice, acidity, soluble solids and vitamin C. The experiment was conducted under a randomized complete block design in a split plot arrangement; the variance and means of the data were statistically analyzed with SAS. And optimal response is between irrigation and fruit quality interaction was obtained with irrigation L1 and fertilization N2. We obtained the highest values in the response variables when the highest amount of water was applied L1, regardless of fertilizer applications, indicating that a lower water supply not only affects the performance of the plant, but also the quality of the fruit, minimizing market opportunities.

  19. Assisted phytoremediation of heavy metal contaminated soil from a mined site with Typha latifolia and Chrysopogon zizanioides.

    Science.gov (United States)

    Anning, Alexander Kofi; Akoto, Ruth

    2018-02-01

    Chemically assisted phytoremediation is fast gaining attention as a biotechnology to accelerate heavy metal removal from contaminated substrates, but how different chemical amendments affect the process remains an important research question. Here, bioaccumulation factor (BAF), translocation factor (TF), removal efficiency (RE) and uptake of Hg, As, Pb, Cu and Zn by cattail (Typha latifolia) and vetiver (Chrysopogon zizanioides) were quantified in a potted experiment to determine the effects of amendments on the phytoremediation success. Baseline concentrations of heavy metals within the studied mined site were determined. The experiment involved three soil treatments (each comprising 16 samples amended with 0.05mol/L ethylene di-aminetetraacetic acid (EDTA), 3g of aluminum sulfate [Al 2 (SO 4 ) 3 ], and unamended control) transplanted with equal numbers of vetiver and cattail. Growth performance (height) of plant species was monitored every two weeks. Sixteen weeks after transplanting, heavy metal levels in plant and soil samples were quantified following standard protocols, and the biomass and root length measured for each plant species. Results indicated strong negative impact of mining activities on heavy metal levels of soil in the study area. Soil amendment considerably enhanced the BAF, TF, RE and uptake but the effect varied with plant species and heavy metal in question. The amendment also stimulated strong positive correlation between RE and BAF, TF and metal uptake, and generally did not show any negative effects on plant growth performance. In general, soil amendment aided the accumulation and translocation of heavy metals in the plant species studied, and could be explored for cleaning up contaminated sites. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. KEMAMPUAN TANAMAN EKOR KUCING (Typha latifolia DAN PURUN TIKUS (Eleocharis dulcis DALAM PENURUNAN KONSENTRASI Fe DAN Mn DARI AIR LIMBAH PIT BARAT PT PAMAPERSADA NUSANTARA DISTRIK KCMB KABUPATEN BANJAR

    Directory of Open Access Journals (Sweden)

    Muhammad Sulthoni A. D. N.

    2016-10-01

    Full Text Available Research on the Ability Test Ekor kucing Plants (Typha latifolia and Purun tikus (Eleocharis dulcis in Fe and Mn concentrations decrease from the West Pit Wastewater PT Pamapersada District KCMB Kabupaten Banjar. This research held in April 2013 to August 2013. The purpose of this study was to determine the ability of plants Ekor kucing and plants Purun tikus in lowering the concentration of  Fe and Mn from waste coal mine and phytoremediation mechanisms that occur. This research uses experimental and survey methods. Results showed that plants Ekor kucing  and Purun tikus are hiperakumulator plants to Fe and Mn in which the plant is able to absorb Fe respectively by 284% and 92%. For Mn, respectively 207% and 1277%. Phytoremediation mechanisms with Ekor kucing for Fe is fitostabilization  and Purun tikus is fitoextraction, while the Mn is fitoextraction.

  1. Swelling and Degradation of Calcium-Pectic Gel Particles Made of Pectins of Silene vulgaris and Lemna minor Сallus Cultures at Different Concentrations of Pectinase in an Artificial Colon Environment

    Directory of Open Access Journals (Sweden)

    Anatoly A. Shubakov

    2018-03-01

    Full Text Available Spherical calcium-pectic gel particles (CaPGPs were obtained from pectins of callus cultures (CC of campion Silene vulgaris (silenan and duckweed Lemna minor (lemnan, as well as from commercial apple and citrus pectins by the method of ionotropic gelation. We studied the morphological characteristics of the obtained gel particles and found that the largest gel particles were formed from citrus pectin (CP, and the densest gel particles were formed from lemnan pectin (LP. The swelling and degradation of CaPGPs were comparatively evaluated by incubation in a simulated gastrointestinal environment. The swelling and degradation of CaPGPs formed from pectins of the silenan and lemnan callus cultures were studied at different concentrations of pectinase (0.4, 0.8 and 1.7 mg/ml in the simulated fluid of the colon. It has been established that the CaPGPs obtained from lemnan are more resistant to degradation in the simulated colon fluid than CaPGP obtained from silenan. It was shown that the concentration of pectinase in the simulated fluid of the colon and the type of pectin affect the degradability of CaPGPs formed on the basis of pectins of callus cultures.

  2. EVALUACIÓN DE LA CINÉTICA DE ADSORCIÓN DE Zn2+ Y Cd2+ A PARTIR DE SOLUCIONES UNITARIAS Y BINARIAS POR RAÍCES DE Eichhornia crassipes Y Typha latifolia

    Directory of Open Access Journals (Sweden)

    Carolina Martínez

    2013-01-01

    Full Text Available In this work, the kinetic modeling of adsorption of Zn 2+ and Cd2+ in roots of Typha latifolia (cattail and Eichhornia crassipes (water hyacinth were evaluated. The study was done using solutions containing one or both ions. The experiments were performed using carbon paste electrodes modified with the roots. The model that best describes the kinetics of both ions in the two roots is the pseudo second order’s one. We also determined that both ions accumulate faster and in greater amounts on Eichhornia crassipes. Indeed, according to potentiometric titration and infrared spectra Fourier transformation, the number of adsorption sites is higher in this root. In the same manner, it was shown that both roots accumulate more Cd 2+ than Zn2+, and when the adsorption is made from a mixture, cadmium inhibits the accumulation of zinc.

  3. Comparative study of bio-ethanol production from mahula (Madhuca latifolia L.) flowers by Saccharomyces cerevisiae cells immobilized in agar agar and Ca-alginate matrices

    Energy Technology Data Exchange (ETDEWEB)

    Behera, Shuvashish; Mohanty, Rama Chandra [Department of Botany, Utkal University, Vani Vihar, Bhubaneswar 751004, Orissa (India); Kar, Shaktimay; Ray, Ramesh Chandra [Microbiology Laboratory, Central Tuber Crops Research Institute (Regional Centre), Bhubaneswar 751019, Orissa (India)

    2010-01-15

    Batch fermentation of mahula (Madhuca latifolia L., a tree commonly found in tropical rain forest) flowers was carried out using immobilized cells (in agar agar and calcium alginate) and free cells of Saccharomyces cerevisiae. The ethanol yields were 151.2, 154.5 and 149.1 g kg{sup -1} flowers using immobilized (in agar agar and calcium alginate) and free cells, respectively. Cell entrapment in calcium alginate was found to be marginally superior to those in agar agar (2.2% more) as well as over free cell (3.5% more) as regard to ethanol yield from mahula flowers is concerned. Further, the immobilized cells were physiologically active at least for three cycles [150.6, 148.5 and 146.5 g kg{sup -1} (agar agar) and 152.8, 151.5 and 149.5 g kg{sup -1} flowers (calcium alginate) for first, second and third cycle, respectively] of ethanol fermentation without apparently lowering the productivity. Mahula flowers, a renewable, non-food-grade cheap carbohydrate substrate from non-agricultural environment such as forest can serve as an alternative to food grade sugar/starchy crops such as maize, sugarcane for bio-ethanol production. (author)

  4. Influence of spike lavender (Lavandula latifolia Med.) essential oil in the quality, stability and composition of soybean oil during microwave heating.

    Science.gov (United States)

    Rodrigues, Nuno; Malheiro, Ricardo; Casal, Susana; Asensio-S-Manzanera, M Carmen; Bento, Albino; Pereira, José Alberto

    2012-08-01

    Lipids oxidation is one of the main factors leading to quality losses in foods. Its prevention or delay could be obtained by the addition of antioxidants. In this sense the present work intend to monitor the protective effects of Lavandula latifolia essential oil during soybean oil microwave heating. To achieve the proposed goal quality parameters (free acidity, peroxide value, specific coefficients of extinction and ΔK), fatty acids profile, tocopherols and tocotrienols composition, antioxidant activity and oxidative stability were evaluated in soybean oil with and without spike lavender essential oils (EO) submitted to different microwave heating exposure times (1, 3, 5, 10 and 15 min; 1000 Watt) with a standard domestic microwave equipment. Microwave heating induced severe quality and composition losses, mainly above 3 min of microwave heating, regardless the sample tested. However, spike lavender EO addition counteracts the oxidation comparatively to control oils, by presenting enhanced values in quality parameters. A higher protection in unsaturated fatty acids loss was also observed as well as a higher antioxidant activity and oxidative stability. The microwave heating effects were clearly different in the samples with essential oils addition, allowing discrimination from plain soybean oils by a principal component analysis, being also capable to discriminate the different heating times tested within each sample. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. On flavonoid accumulation in different plant parts: Variation patterns among individuals and populations in the shore campion (Silene littorea.

    Directory of Open Access Journals (Sweden)

    Jose Carlos Del Valle

    2015-10-01

    Full Text Available The presence of anthocyanins in flowers and fruits is frequently attributed to attracting pollinators and dispersers. In vegetative organs, anthocyanins and other non-pigmented flavonoids such as flavones and flavonols may serve protective functions against UV radiation, cold, heat, drought, salinity, pathogens and herbivores; thus, these compounds are usually produced as a plastic response to such stressors. Although the independent accumulation of anthocyanins in reproductive and vegetative tissues is commonly postulated due to differential regulation, the accumulation of flavonoids within and among populations has never been thoroughly compared. Here, we investigated the shore campion (Silene littorea, Caryophyllaceae which exhibits variation in anthocyanin accumulation in its floral and vegetative tissues. We examined the in-situ accumulation of flavonoids in floral (petals and calyxes and vegetative organs (leaves from 18 populations representing the species’ geographic distribution. Each organ exhibited considerable variability in the content of anthocyanins and other flavonoids both within and among populations. In all organs, anthocyanin and other flavonoids were correlated. At the plant level, the flavonoid content in petals, calyxes and leaves was not correlated in most of the populations. However, at the population level, the mean amount of anthocyanins in all organs was positively correlated, which suggests that the variable environmental conditions of populations may play a role in anthocyanin accumulation. These results are unexpected because the anthocyanins are usually constitutive in petals, yet contingent to environmental conditions in calyxes and leaves. Anthocyanin variation in petals may influence pollinator attraction and subsequent plant reproduction, yet the amount of anthocyanins may be a direct response to environmental factors. In populations on the west coast, a general pattern of increasing accumulation of

  6. Analytical Modelling of Canopy Interception Loss from a Juvenile Lodgepole Pine (Pinus contorta var. latifolia) Stand

    Science.gov (United States)

    Carlyle-Moses, D. E.; Lishman, C. E.

    2015-12-01

    In the central interior of British Columbia (BC), Canada, the mountain pine beetle (Dendroctonus ponderosae Hopkins) (MPB) has severely affected the majority of pine species in the region, especially lodgepole pine (Pinus contorta Douglas ex Louden var. latifolia Engelm. ex S. Watson). The loss of mature lodgepole pine stands, including those lost to salvage logging, has resulted in an increase in the number of juvenile pine stands in the interior of BC through planting and natural regrowth. With this change from mature forests to juvenile forests at such a large spatial scale, the water balance of impacted areas may be altered, although the magnitude of such change is uncertain. Previous studies of rainfall partitioning by lodgepole pine and lodgepole pine dominated canopies have focused on mature stands. Thus, rainfall, throughfall and stemflow were measured and canopy interception loss was derived during the growing season of 2010 in a juvenile lodgepole pine dominated stand located approximately 60 km NNW of Kamloops, BC at 51°12'49" N 120°23'43" W, 1290 m above mean sea level. Scaling up from measurements for nine trees, throughfall, stemflow and canopy interception loss accounted for 87.7, 1.8 and 10.5 percent of the 252.9 mm of rain that fell over 38 events during the study period, respectively. The reformulated versions of the Gash and Liu analytical interception loss models estimated cumulative canopy interception loss at 24.7 and 24.6 mm, respectively, compared with the observed 26.5 mm; an underestimate of 1.8 and 1.9 mm or 6.8 and 7.2% of the observed value, respectively. Our results suggest that canopy interception loss is reduced in juvenile stands compared to their mature counterparts and that this reduction is due to the decreased storage capacity offered by these younger canopies. Evaporation during rainfall from juvenile canopies is still appreciable and may be a consequence of the increased proportion of the canopy exposed to wind during events.

  7. Leaves and roots of Typha latifolia L. and Iris pseudacorus L. as bioindicators of contamination of bottom sediments by heavy metals

    Directory of Open Access Journals (Sweden)

    Parzych Agnieszka

    2016-12-01

    Full Text Available The paper concerns the bioaccumulation of zinc, nickel, iron and manganese in leaves and roots of selected macrophytes from the Krzynia Reservoir (northern Poland. The research was conducted within the area of 10 stations situated in the littoral zone of the reservoir. Samples of surface waters, bottom sediments and plants were taken in summer. Heavy metal content was determined by the atomic absorption spectrometry method (ASA. The concentration of heavy metals in the waters of Krzynia Reservoir was low and noinfluence of anthropogenic factors was found. Concentration of heavy metals in the examined bottom sediments was low and remained within the limits of the geochemical background for Zn and Fe. In the case of Ni and Mn it sporadically exceeded the level of the geochemical background. The tested plants mainly accumulated heavy metals in roots, with the exception of nickel which appeared in larger quantities in leaves. The relationships among the content of the determined elements in the organs of macrophytes was identical for the tested species and could be arranged into the following sequences: Mn>Fe>Ni>Zn in leaves and Fe>Mn>Zn>Ni in roots. Statistically significant differences were found in the content of Mn in leaves and Zn and Fe in the roots of Typha latifolia L. and Iris pseudacorus L. By accumulating substantial quantities of heavy metals in their organs, macrophytes constitute an effective protective barrier for the waters and bottom sediments.

  8. The X Chromosome Is Necessary for Somatic Development in the Dioecious Silene latifolia: Cytogenetic and Molecular Evidence and Sequencing of a Haploid Genome

    Czech Academy of Sciences Publication Activity Database

    Soukupová, Magda; Nevrtalová, Eva; Čížková, Jana; Vogel, Ivan; Čegan, Radim; Hobza, Roman; Vyskot, Boris

    2014-01-01

    Roč. 143, 1-3 (2014), s. 96-103 ISSN 1424-8581 R&D Projects: GA ČR(CZ) GBP501/12/G090; GA ČR(CZ) GAP501/12/2220; GA ČR(CZ) GAP501/10/0102; GA MŠk(CZ) LM2010005; GA MŠk LO1204 Institutional support: RVO:68081707 Keywords : Anther culture * Cytometry * Dihaploids Subject RIV: BO - Biophysics; EF - Botanics (UEB-Q) Impact factor: 1.561, year: 2014

  9. Sexual dimorphism in white campion: complex control of carpel number is revealed by Y chromosome deletions

    International Nuclear Information System (INIS)

    Lardon, A.; Georgiev, S.; Aghmir, A.; Le Merrer, G.; Negrutiu, I.

    1999-01-01

    Sexual dimorphism in the dioecious plant white campion (Silene latifolia = Melandrium album) is under the control of two main regions on the Y chromosome. One such region, encoding the gynoecium-suppressing function (GSF), is responsible for the arrest of carpel initiation in male flowers. To generate chromosomal deletions, we used pollen irradiation in male plants to produce hermaphroditic mutants (bsx mutants) in which carpel development was restored. The mutants resulted from alterations in at least two GSF chromosomal regions, one autosomal and one located on the distal half of the (p)-arm of the Y chromosome. The two mutations affected carpel development independently, each mutation showing incomplete penetrance and variegation, albeit at significantly different levels. During successive meiotic generations, a progressive increase in penetrance and a reduction in variegation levels were observed and quantified at the level of the Y-linked GSF (GSF-Y). Possible mechanisms are proposed to explain the behavior of the bsx mutations: epigenetic regulation or/and second-site mutation of modifier genes. In addition, studies on the inheritance of the hermaphroditic trait showed that, unlike wild-type Y chromosomes, deleted Y chromosomes can be transmitted through both the male and the female lines. Altogether, these findings bring experimental support, on the one hand, to the existence on the Y chromosome of genic meiotic drive function(s) and, on the other hand, to models that consider that dioecy evolved through multiple mutation events. As such, the GSF is actually a system containing more than one locus and whose primary component is located on the Y chromosome

  10. Pas de deux: An Intricate Dance of Anther Smut and Its Host

    Directory of Open Access Journals (Sweden)

    Su San Toh

    2018-02-01

    Full Text Available The successful interaction between pathogen/parasite and host requires a delicate balance between fitness of the former and survival of the latter. To optimize fitness a parasite/pathogen must effectively create an environment conducive to reproductive success, while simultaneously avoiding or minimizing detrimental host defense response. The association between Microbotryum lychnidis-dioicae and its host Silene latifolia serves as an excellent model to examine such interactions. This fungus is part of a species complex that infects species of the Caryophyllaceae, replacing pollen with the fungal spores. In the current study, transcriptome analyses of the fungus and its host were conducted during discrete stages of bud development so as to identify changes in fungal gene expression that lead to spore development and to identify changes associated with infection in the host plant. In contrast to early biotrophic phase stages of infection for the fungus, the latter stages involve tissue necrosis and in the case of infected female flowers, further changes in the developmental program in which the ovary aborts and a pseudoanther is produced. Transcriptome analysis via Illumina RNA sequencing revealed enrichment of fungal genes encoding small secreted proteins, with hallmarks of effectors and genes found to be relatively unique to the Microbotryum species complex. Host gene expression analyses also identified interesting sets of genes up-regulated, including those involving stress response, host defense response, and several agamous-like MADS-box genes (AGL61 and AGL80, predicted to interact and be involved in male gametophyte development.

  11. Citrus tristeza virus (CTV influence on the behavior of Tahiti lime (Citrus latifoliaTanaka grafted on six rootstocks in the plain piedmont of Colombia (1997-2008

    Directory of Open Access Journals (Sweden)

    Hans Nicolás Chaparro Zambrano

    2013-01-01

    Full Text Available Tahiti lime, Citrus latifolia Tanaka (Rutaceae, is susceptible to Citrus Tristeza Virus (CTV, and if affected, decreases the profitability of the crop. In the well-drained high terrace of the Meta piedmont, the influence of the virus attack was evaluated on the performance of Tahiti lime grafted on six rootstocks (Carrizo; Sunki × English; Sunki × Jacobson; Pomeroy; Rubidoux, y Kryder 15-3 on a completely randomized experiment design taking each tree as an experimental unit. A comparison of means and inferential statistic were used for: plant height, height and canopy diameter; canopy volume, yield and severity of CTV. All rootstocks showed homogenous height. Carrizo was the exception with less size and canopy volume. The highest accumulated fruit yield (Kg/tree wasobtained by Sunki x English, followed by Rubidoux and the lowest yield was obtained by Carrizo. The highest yield efficiency of average canopy volume was obtained with Sunki x Jacobson. The Tahiti lime yield and morphological development fell in the seventh year (2007 in all rootstocks, due to an infection caused by a mix of isolates of CTV type Madeira and type B128, isolates which cause stem channeling : type B31 which causes moderate stem channeling and B7 and VT isolate,

  12. Nitrous oxide emission from polyculture constructed wetlands: Effect of plant species

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yanhua [School of Environmental Science and Engineering, Shanghai Jiaotong University, 800 Dong Chuan Road, Min Hang, Shanghai 200240 (China); Inamori, Ryuhei [Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanayagawa, Fukushima 960-1296 (Japan); Kong Hainan [School of Environmental Science and Engineering, Shanghai Jiaotong University, 800 Dong Chuan Road, Min Hang, Shanghai 200240 (China)], E-mail: remanda@126.com; Xu Kaiqin [National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506 (Japan); State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan Unviversity, Wuhan 430072 (China); Inamori, Yuhei [Faculty of Symbiotic Systems Science, Fukushima University, 1 Kanayagawa, Fukushima 960-1296 (Japan); Kondo, Takashi [National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506 (Japan); Zhang Jixiang [School of Economics and Management, Southeast University, Nanjing, Jiangsu 210096 (China)

    2008-03-15

    Loss of nitrogen from the soil-plant system has raised environmental concern. This study assessed the fluxes of nitrous oxide (N{sub 2}O) in the subsurface flow constructed wetlands (CWs). To better understand the mechanism of N{sub 2}O emission, spatial distribution of ammonia-oxidizing bacteria (AOB) in four kinds of wetlands soil were compared. N{sub 2}O emission data showed large temporal and spatial variation ranging from -5.5 to 32.7 mg N{sub 2}O m{sup -2} d{sup -1}. The highest N{sub 2}O emission occurred in the cell planted with Phragmites australis and Zizania latifolia. Whereas, the lower emission rate were obtained in the cell planted with P. australis and Typha latifolia. These revealed that Z. latifolia stimulated the N{sub 2}O emission. Transportation of more organic matter and oxygen for AOB growth may be the reason. The study of AOB also supported this result, indicating that the root structure of Z. latifolia was favored by AOB for N{sub 2}O formation. - Zizania latifolia has a large contribution to global warming.

  13. Up-regulation of an N-terminal truncated 3-hydroxy-3-methylglutaryl CoA reductase enhances production of essential oils and sterols in transgenic Lavandula latifolia.

    Science.gov (United States)

    Muñoz-Bertomeu, Jesús; Sales, Ester; Ros, Roc; Arrillaga, Isabel; Segura, Juan

    2007-11-01

    Spike lavender (Lavandula latifolia) essential oil is widely used in the perfume, cosmetic, flavouring and pharmaceutical industries. Thus, modifications of yield and composition of this essential oil by genetic engineering should have important scientific and commercial applications. We generated transgenic spike lavender plants expressing the Arabidopsis thaliana HMG1 cDNA, encoding the catalytic domain of 3-hydroxy-3-methylglutaryl CoA reductase (HMGR1S), a key enzyme of the mevalonic acid (MVA) pathway. Transgenic T0 plants accumulated significantly more essential oil constituents as compared to controls (up to 2.1- and 1.8-fold in leaves and flowers, respectively). Enhanced expression of HMGR1S also increased the amount of the end-product sterols, beta-sitosterol and stigmasterol (average differences of 1.8- and 1.9-fold, respectively), but did not affect the accumulation of carotenoids or chlorophylls. We also analysed T1 plants derived from self-pollinated seeds of T0 lines that flowered after growing for 2 years in the greenhouse. The increased levels of essential oil and sterols observed in the transgenic T0 plants were maintained in the progeny that inherited the HMG1 transgene. Our results demonstrate that genetic manipulation of the MVA pathway increases essential oil yield in spike lavender, suggesting a contribution for this cytosolic pathway to monoterpene and sesquiterpene biosynthesis in leaves and flowers of the species.

  14. A graphical user interface for 3D pre & post processing: state-of-the-art and new developments

    International Nuclear Information System (INIS)

    Stankovski, Zarko

    2011-01-01

    'La Java de Silene' (Silene) is an original Graphical User Interface (GUI), written in Java language, for generation of 3D arbitrarily shaped geometries for the neutron transport codes used at CEA. Silene provides data for APOLLO2 input format as well as for some other codes like Monte Carlo TRIPOLI4 code. In addition, the software serves as an experimental tool to explore the needs and feasibility for the GUI of the currently developing APOLLO3. This paper summarizes the principles of the software and presents some new capabilities. The interface deals simultaneously with two kinds of geometries: regular and unstructured, arranged in collections. Unstructured geometries are built visually and regular ones visually or by using text editor. Regular geometries consist of sets of predefined and parameterized components. The new developments will improve the efficiency of components with the ability to use variables instead of fixed values. Use of variables, derived components (mutants) and combination of media with generic names and meshes with physical names allow the management of collections with much different isotopic enrichment without increasing the number of fuel cells. The object of all these recent developments is to ensure an efficient and secure management of large and complex geometrical configurations. The effectiveness of the current version of Silene is illustrated with an example for a Boiling Water Reactor Assembly. (author)

  15. A graphical user interface for 3D pre & post processing: state-of-the-art and new developments

    Energy Technology Data Exchange (ETDEWEB)

    Stankovski, Zarko, E-mail: zstankovski@cea.fr [Commissariat a l' Energie Atomique (CEA Saclay), Gif-sur-Yvette Cedex (France)

    2011-07-01

    'La Java de Silene' (Silene) is an original Graphical User Interface (GUI), written in Java language, for generation of 3D arbitrarily shaped geometries for the neutron transport codes used at CEA. Silene provides data for APOLLO2 input format as well as for some other codes like Monte Carlo TRIPOLI4 code. In addition, the software serves as an experimental tool to explore the needs and feasibility for the GUI of the currently developing APOLLO3. This paper summarizes the principles of the software and presents some new capabilities. The interface deals simultaneously with two kinds of geometries: regular and unstructured, arranged in collections. Unstructured geometries are built visually and regular ones visually or by using text editor. Regular geometries consist of sets of predefined and parameterized components. The new developments will improve the efficiency of components with the ability to use variables instead of fixed values. Use of variables, derived components (mutants) and combination of media with generic names and meshes with physical names allow the management of collections with much different isotopic enrichment without increasing the number of fuel cells. The object of all these recent developments is to ensure an efficient and secure management of large and complex geometrical configurations. The effectiveness of the current version of Silene is illustrated with an example for a Boiling Water Reactor Assembly. (author)

  16. Molecular Evidence for the Hybrid Origin of Ilex dabieshanensis (Aquifoliaceae.

    Directory of Open Access Journals (Sweden)

    Lin Shi

    Full Text Available Ilex, the largest genus of dioecious woody plants, is a good study system to assess the role of hybridization in speciation and evolution. Ilex dabieshanensis, a tree endemic to Dabieshan Mountains region, was initially described as a new species. Based on morphological intermediacy and sympatric distribution with its putative parental species, I. cornuta and I. latifolia, we proposed it as a natural hybrid between them. In this study, we sequenced one chloroplast intergenic spacer (trnH-psbA and two nuclear genes (gapC and nepGS in I. dabieshanensis and its putative parental species to test the hybrid origin hypothesis. Our results showed that there were one to two differentially fixed sequence differences between I. cornuta and I. latifolia at the two nuclear genes. Twelve of the 14 individuals of I. dabieshanensis exhibited additivity in chromatograms on these differentially fixed sites at both nuclear genes, and the remaining two exhibited additivity in chromatograms on the fixed site at only the nepGS gene. Except one haplotype of I. cornuta at the nepGS gene, all of the haplotypes of I. cornuta at the two nuclear genes were well separated from those of I. latifolia, and most haplotypes of I. dabieshanensis were shared with those of I. cornuta and I. latifolia. Phylogenetic analysis of these haplotypes was largely consistent with haplotype network analysis. I. cornuta and I. latifolia differed by two nucleotide substitutions in the chloroplast intergenic spacer, and 12 individuals of I. dabieshanensis had the same sequences as I. latifolia, while the remaining two were identical with I. cornuta. The molecular data provide convincing evidence for the hybrid origin of I. dabieshanensis and asymmetrical direction of hybridization. One haplotype of I. cornuta at the nepGS gene was nested with those of I. latifolia, indicating introgression to I. cornuta.

  17. Dose evaluation in criticality accidents using response of panasonic TL personal dosemeters (UD-809/UD-802)

    International Nuclear Information System (INIS)

    Zeyrek, C. T.; Guenduez, H.

    2012-01-01

    This study gives the results of dosimetry measurements carried out in the Silene reactor at Valduc (France) with neutron and photon personal thermoluminescence dosemeters (TLDs) in mixed neutron and gamma radiation fields, in the frame of the international accident dosimetry intercomparison programme in 2002. The intercomparison consisted of a series of three irradiation scenarios. The scenarios took place at the Valduc site (France) by using the Silene experimental reactor. For neutron and photon dosimetry, Panasonic model UD-809 and UD-802 personal TLDs were used together. (authors)

  18. Salvadorianae. III. Una descripció prelinneana de Silene niceensis All., deguda a Jaume Salvador i Pedrol, a l'edició de 1686 del Botanicum Monspeliense de Pèire Magnol

    Directory of Open Access Journals (Sweden)

    Camarasa, Josep M.

    2000-12-01

    Full Text Available Silene niceensis All. (Cariophillaceae is a plant found on litoral sands of Western Mediterranian and also of Iberian Atlantic shores from Gibraltar to the Rias Baixas and in some places in Greece. It had been described twice in prelinnean times but Linné has neglected it in his works. First prelinnean description, though published by Pierre Magnol in the Appedix to the second edition (1686 of Botanicum monspeliense,has been wrote on the basis of materials and a short description sent to Magnol by Jaume Salvador i Pedrol. One specimen of this plant in Salvador Herbarium hold a short description that could be the original one by Jaume Salvador. The second one was published on a different name by Tournefort in Institutiones Rei herbariae. It is also one specimen of S. niceensisAll. in Salvador Herbarium under this identity. Pourret, studying this herbarium to put on etiquets the linnean name of each specimen (1792-98, realize the specific identity of both S. niceensis All. specimens but ignoring the description published by Allioni in 1773 he give them the new name of S. arenaria Pourr. Also Desfontaines described under the name of S. arenaria Desf. in his Flora Atlantica (1798-99 the same species on the basis of specimens collected near the Gibraltar Strait. Both. Pourrett and Desfontaines names, or today invalid and under sinonimy.

    La cariofil làcia Silene niceensis All. pròpia dels sorrats litorals de la Mediterrània occidental i present també a les costes atlàntiques ibèriques. des de l' estret de Gibraltar fins a les Rias Baixas i en alguna localitat grega, havia estar descrita al menys dues vegades temps prelinneans malgrat que Linné mateix la ignorés a les seves obres. La primera descripció prelinneana. bé que publicada por Péire Magnol a l’apèndix a la segona edició del seu Botanicum monspeliense,. es feu sobre la base de materials i fins i tot d

  19. Lower prevalence but similar fitness in a parasitic fungus at higher radiation levels near Chernobyl.

    Science.gov (United States)

    Aguileta, Gabriela; Badouin, Helene; Hood, Michael E; Møller, Anders P; Le Prieur, Stephanie; Snirc, Alodie; Siguenza, Sophie; Mousseau, Timothy A; Shykoff, Jacqui A; Cuomo, Christina A; Giraud, Tatiana

    2016-07-01

    Nuclear disasters at Chernobyl and Fukushima provide examples of effects of acute ionizing radiation on mutations that can affect the fitness and distribution of species. Here, we investigated the prevalence of Microbotryum lychnidis-dioicae, a pollinator-transmitted fungal pathogen of plants causing anther-smut disease in Chernobyl, its viability, fertility and karyotype variation, and the accumulation of nonsynonymous mutations in its genome. We collected diseased flowers of Silene latifolia from locations ranging by more than two orders of magnitude in background radiation, from 0.05 to 21.03 μGy/h. Disease prevalence decreased significantly with increasing radiation level, possibly due to lower pollinator abundance and altered pollinator behaviour. Viability and fertility, measured as the budding rate of haploid sporidia following meiosis from the diploid teliospores, did not vary with increasing radiation levels and neither did karyotype overall structure and level of chromosomal size heterozygosity. We sequenced the genomes of twelve samples from Chernobyl and of four samples collected from uncontaminated areas and analysed alignments of 6068 predicted genes, corresponding to 1.04 × 10(7)  base pairs. We found no dose-dependent differences in substitution rates (neither dN, dS, nor dN/dS). Thus, we found no significant evidence of increased deleterious mutation rates at higher levels of background radiation in this plant pathogen. We even found lower levels of nonsynonymous substitution rates in contaminated areas compared to control regions, suggesting that purifying selection was stronger in contaminated than uncontaminated areas. We briefly discuss the possibilities for a mechanistic basis of radio resistance in this nonmelanized fungus. © 2016 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

  20. Influence of Multiple Infection and Relatedness on Virulence: Disease Dynamics in an Experimental Plant Population and Its Castrating Parasite

    Science.gov (United States)

    Buono, Lorenza; López-Villavicencio, Manuela; Shykoff, Jacqui A.; Snirc, Alodie; Giraud, Tatiana

    2014-01-01

    The level of parasite virulence, i.e., the decrease in host's fitness due to a pathogen, is expected to depend on several parameters, such as the type of the disease (e.g., castrating or host-killing) and the prevalence of multiple infections. Although these parameters have been extensively studied theoretically, few empirical data are available to validate theoretical predictions. Using the anther smut castrating disease on Silene latifolia caused by Microbotryum lychnidis-dioicae, we studied the dynamics of multiple infections and of different components of virulence (host death, non-recovery and percentage of castrated stems) during the entire lifespan of the host in an experimental population. We monitored the number of fungal genotypes within plants and their relatedness across five years, using microsatellite markers, as well as the rates of recovery and host death in the population. The mean relatedness among genotypes within plants remained at a high level throughout the entire host lifespan despite the dynamics of the disease, with recurrent new infections. Recovery was lower for plants with multiple infections compared to plants infected by a single genotype. As expected for castrating parasites, M. lychnidis-dioicae did not increase host mortality. Mortality varied across years but was generally lower for plants that had been diseased the preceding year. This is one of the few studies to have empirically verified theoretical expectations for castrating parasites, and to show particularly i) that castrated hosts live longer, suggesting that parasites can redirect resources normally used in reproduction to increase host lifespan, lengthening their transmission phase, and ii) that multiple infections increase virulence, here in terms of non-recovery and host castration. PMID:24892951

  1. Study of the comparative dynamics of the incorporation of tissue free-water tritium (TFWT) in bulrushes (Typha latifolia) and carp (Cyprinus carpio) in the Almaraz nuclear power plant cooling reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Baeza, A. [Department of Applied Physics, Faculty of Veterinary, University of Extremadura, Avda de la Universidad s/n, 10071 Caceres (Spain)], E-mail: ymiralle@unex.es; Garcia, E. [Department of Applied Physics, Technical Forest Engineering School, University of Extremadura, 10600 (Plasencia) Caceres (Spain); Paniagua, J.M. [Department of Applied Physics, Polytechnic School, University of Extremadura, Avda de la Universidad s/n, 10071 Caceres (Spain); Rodriguez, A. [Department of Applied Physics, Faculty of Veterinary, University of Extremadura, Avda de la Universidad s/n, 10071 Caceres (Spain)

    2009-03-15

    The Almaraz nuclear power plant (Spain) uses the water of Arrocampo reservoir for cooling, and consequently raises the radioactive levels of the aquatic ecosystem of this reservoir. From July 2002 to June 2005, monthly samples of surface water, bulrushes (Typha latifolia) and carp (Cyprinus carpio) were collected from this reservoir. They were analyzed to determine the temporal evolution of the levels of {sup 3}H in surface water and of its transfer from the surface water to free-water in the tissues (TFWT) of the aforementioned two organisms. The tritium levels in the surface water oscillate with a biannual period, with their values in the study period ranging between 53 and 433 Bq/L. The incorporation of tritium to bulrushes and carp was fairly similar, the respective mean concentration factors being 0.74 and 0.8 (unitless, as Bq/L tissue water per Bq/L reservoir water). The temporal evolution of the levels fairly closely followed that observed for the surface water tritium, although detailed analysis showed the dominant periodicity for the bulrushes to be annual. This difference reflects the influence on the incorporation of tritium to bulrushes of diverse environmental and metabolic factors, especially evapotranspiration and the seasonal growth of this plant.

  2. Study of the comparative dynamics of the incorporation of tissue free-water tritium (TFWT) in bulrushes (Typha latifolia) and carp (Cyprinus carpio) in the Almaraz nuclear power plant cooling reservoir

    International Nuclear Information System (INIS)

    Baeza, A.; Garcia, E.; Paniagua, J.M.; Rodriguez, A.

    2009-01-01

    The Almaraz nuclear power plant (Spain) uses the water of Arrocampo reservoir for cooling, and consequently raises the radioactive levels of the aquatic ecosystem of this reservoir. From July 2002 to June 2005, monthly samples of surface water, bulrushes (Typha latifolia) and carp (Cyprinus carpio) were collected from this reservoir. They were analyzed to determine the temporal evolution of the levels of 3 H in surface water and of its transfer from the surface water to free-water in the tissues (TFWT) of the aforementioned two organisms. The tritium levels in the surface water oscillate with a biannual period, with their values in the study period ranging between 53 and 433 Bq/L. The incorporation of tritium to bulrushes and carp was fairly similar, the respective mean concentration factors being 0.74 and 0.8 (unitless, as Bq/L tissue water per Bq/L reservoir water). The temporal evolution of the levels fairly closely followed that observed for the surface water tritium, although detailed analysis showed the dominant periodicity for the bulrushes to be annual. This difference reflects the influence on the incorporation of tritium to bulrushes of diverse environmental and metabolic factors, especially evapotranspiration and the seasonal growth of this plant

  3. THE ABILITY OF LEAVES AND RHIZOMES OF AQUATIC PLANTS TO ACCUMULATE MACRO- AND MICRONUTRIENTS

    Directory of Open Access Journals (Sweden)

    Agnieszka Edyta Parzych

    2015-06-01

    Full Text Available The samples of macrophytes and bottom sediments originated from the littoral zone of the Słupia River were collected in summer 2013. The aim of this study was to compare the properties of the accumulation of leaves and rhizomes of Glyceria maxima, Phragmites australis, Typha latifolia and Phalaris arundinacea for macro- and micronutrients. The largest quantities of macroelements were found in the leaves of the examined species, and microelements dominated the rhizomes of most examined macrophytes except for Mn in P.australis and T.latifolia. The obtained results show that N and K dominated in the leaves of P.arundinacea, P and Mg in the leaves of P.australis, and Ca in the leaves of G.maxima. The largest quantities of N, P and K were cumulated in the rhizomes of P.arundinacea, while Mg and Ca in the rhizome of T.latifolia. The leaves of aquatic plants accumulated from 1354.9 mmolc·kg-1 (T.latifolia to 1844.0 mmolc·kg-1 (P.arundinacea, and rhizomes from 985.8 mmolc·kg-1 (G.maxima to 1335.2 mmolc·kg-1 (P.arundinacea of all the analyzed components. In these species of macrophytes lower accumulated value of the sum of macro- and microelements were found in the rhizomes. The share of nitrogen was 42.4–59.8% of this amount, phosphorus 4.3–8.6%, potassium 22.8–35.1%, calcium from 2,6% to 12.4%, magnesium 3.0–7.5%, and heavy metals were from 0.6% (G.maxima to 1.2% (T.latifolia in leaves and from 2.2% (T.latifolia to 8.7% (G.maxima in rhizomes.

  4. Download this PDF file

    African Journals Online (AJOL)

    observed in strychnine poisoning and death. Pentobarbital induced sleep in rats. The methanolic extract of N. Latifolia root bark did not influence the duration of sleep following pentobarbital administration in rats at the dose range of 50-200 mg/kg (Table 1). Table 1: The effects of the methanolic extract of N. latifolia root bark ...

  5. Effects of feeding the herb Borreria latifolia on the meat quality of village chickens in Malaysia.

    Science.gov (United States)

    Abbood, Ali A; Kassim, Azhar Bin; Jawad, Hasan S A; Manap, Yazid Abdul; Sazili, Awis Qurni

    2017-06-01

    An experiment was carried out to estimate the meat quality characteristics of village chickens (Gallus gallus) fed diets supplemented with dry leaves of Borreria latifolia (BL) used as a potential antioxidant source in chicken feed. In this study, 252 sexed 9-week-old village chickens with mean live body weight of 1,525.4 g for males and 1,254.1 g for females were divided into 7 groups (each group 18 birds) for each sex represented in 2 experiments. The first experiment was to evaluate the antioxidant activity of BL and the effect on meat quality through a comparison with Rosmarinus officinalis (RO); hence, 3 groups were conducted and included: T1 (control), basal diet without supplementation; T2, basal diet with 1% of BL; T3, basal diet with 1% of RO. T2 and T3 significantly affect pH value, lipid oxidation, cooking loss, and overall acceptability compared to T1, while no significant difference was observed between the dietary groups in respect of drip loss, color, tenderness, fatty acid profile, and meat composition. Furthermore, a significant effect of sex on lipid oxidation, pH, yellowness, and fatty acid profile was observed. There was no significant effect of sex on WHC, tenderness, lightness, redness, and sensory evaluation. A significant influence of postmortem aging period was detected on lipid oxidation, pH, tenderness, cooking loss, and redness. The obtained result in this study revealed a significance in the interaction of herb by sex in pH parameter and between herb and sex, herb by aging period, sex by aging period, and the herb by sex by aging period interactions with regard to lipid oxidation test. The second experiment was to estimate the effect of 3 different levels of BL on meat quality. Four groups were provided and involved: T1 (control), basal diet without supplementation; T2, basal diet with 1.5% of BL; T3, basal diet with 2% of BL; and T4, basal diet with 2.5% of BL. The result of this study showed a significant effect (P < 0.05) of the

  6. Wild vegetable mixes sold in the markets of Dalmatia (southern Croatia).

    Science.gov (United States)

    Łuczaj, Łukasz; Zovkokončić, Marijana; Miličević, Tihomir; Dolina, Katija; Pandža, Marija

    2013-01-03

    Dalmatia is an interesting place to study the use of wild greens as it lies at the intersection of influence of Slavs, who do not usually use many species of wild greens, and Mediterranean culinary culture, where the use of multiple wild greens is common. The aim of the study was to document the mixtures of wild green vegetables which are sold in all the vegetable markets of Dalmatia. All vendors (68) in all 11 major markets of the Dalmatian coast were interviewed. The piles of wild vegetables they sold were searched and herbarium specimens taken from them. The mean number of species in the mix was 5.7. The most commonly sold wild plants are: Sonchus oleraceus L., Allium ampeloprasum L., Foeniculum vulgare Mill., Urospermum picroides F.W.Schmidt, Papaver rhoeas L., Daucus carota L., Taraxacum sp., Picris echioides L., Silene latifolia Poir. and Crepis spp. Also the cultivated beet (Beta vulgaris L.) and a few cultivated Brassicaceae varieties are frequent components. Wild vegetables from the mix are usually boiled for 20-30 minutes and dressed with olive oil and salt. Altogether at least 37 wild taxa and 13 cultivated taxa were recorded.Apart from the mixes, Asparagus acutifolius L. and Tamus communis L. shoots are sold in separate bunches (they are usually eaten with eggs), as well as some Asteraceae species, the latter are eaten raw or briefly boiled. The rich tradition of eating many wild greens may result both from strong Venetian and Greek influences and the necessity of using all food resources available in the barren, infertile land in the past. Although the number of wild-collected green vegetables is impressive we hypothesize that it may have decreased over the years, and that further in-depth local ethnobotanical studies are needed in Dalmatia to record the disappearing knowledge of edible plants.

  7. Identification and Initial Characterization of the Effectors of an Anther Smut Fungus and Potential Host Target Proteins

    Directory of Open Access Journals (Sweden)

    Venkata S. Kuppireddy

    2017-11-01

    Full Text Available (1 Background: Plant pathogenic fungi often display high levels of host specificity and biotrophic fungi; in particular, they must manipulate their hosts to avoid detection and to complete their obligate pathogenic lifecycles. One important strategy of such fungi is the secretion of small proteins that serve as effectors in this process. Microbotryum violaceum is a species complex whose members infect members of the Caryophyllaceae; M. lychnidis-dioicae, a parasite on Silene latifolia, is one of the best studied interactions. We are interested in identifying and characterizing effectors of the fungus and possible corresponding host targets; (2 Methods: In silico analysis of the M. lychnidis-dioicae genome and transcriptomes allowed us to predict a pool of small secreted proteins (SSPs with the hallmarks of effectors, including a lack of conserved protein family (PFAM domains and also localized regions of disorder. Putative SSPs were tested for secretion using a yeast secretion trap method. We then used yeast two-hybrid analyses for candidate-secreted effectors to probe a cDNA library from a range of growth conditions of the fungus, including infected plants; (3 Results: Roughly 50 SSPs were identified by in silico analysis. Of these, 4 were studied further and shown to be secreted, as well as examined for potential host interactors. One of the putative effectors, MVLG_01732, was found to interact with Arabidopsis thaliana calcium-dependent lipid binding protein (AtCLB and with cellulose synthase interactive protein 1 orthologues; and (4 Conclusions: The identification of a pool of putative effectors provides a resource for functional characterization of fungal proteins that mediate the delicate interaction between pathogen and host. The candidate targets of effectors, e.g., AtCLB, involved in pollen germination suggest tantalizing insights that could drive future studies.

  8. Assessing radiation exposure of herbaceous plant species at the East-Ural Radioactive Trace

    International Nuclear Information System (INIS)

    Karimullina, Elina; Antonova, Elena; Pozolotina, Vera

    2013-01-01

    The East-Ural Radioactive Trace (EURT) is a result of the Mayak Production Association accident that occurred in 1957 in Russia. Radiological assessment improves the interpretation of biological effects of exposure to ionizing radiation. Therefore a modeling approach was used to estimate dose rates on Leonurus quinquelobatus, Silene latifolia, Stellaria graminea and Bromus inermis. Soil-to-organism transfer parameter values are delivered from empirical data of 90 Sr and 137 Cs soil and vegetative plant mass activity concentrations. External and internal whole-body dose rates were calculated using deterministic (The ERICA Tool-Tier 2 and R and D 128/SP1a) and probabilistic (The ERICA Tool-Tier 3) methods. The total dose rate for herbs was under 100 μGy h −1 at the most polluted site. The total absorbed dose rates increased 43–110 times (Tier 3) for different herbaceous plant species along the pollution gradient. Based on these data, it can be concluded that herbaceous plant populations currently exist under low-level chronic exposure at the EURT area. -- Highlights: • A modeling approach (The ERICA Tool-Tier 2, Tier 3 and R and D 128/SP1a) was used to estimate dose rates for herbs growing in the wild at the East-Ural Radioactive Trace. • The highest levels of anthropogenic radiation exposure were determined for herbs at Impact EURT sites. • Total absorbed dose rates increased 43–110 times (Tier 3) for different herbaceous plant species along the pollution gradient. • Total dose rate per plant organism for herbs is under 100 μGy h −1 at the most polluted site. Currently herbaceous plant populations exist under low-level chronic exposure at the EURT area

  9. Disponibilidade e valor nutritivo de forragem de leguminosas nativas (Adesmia DC. e exóticas (Lotus L. Availability and nutritive value of the wild leguminous (Adesmia DC. and exotics (Lotus L.

    Directory of Open Access Journals (Sweden)

    Simone Meredith Scheffer-Basso

    2001-06-01

    Full Text Available O gênero Adesmia DC. possui 17 espécies nativas no Brasil, distribuídas nos Estados do Sul, cuja importância está vinculada a sua adaptação ao solo e clima regionais, além de ser de crescimento hibernal (temperadas. Este trabalho teve o objetivo comparar o padrão de acúmulo de matéria seca (MS e valor nutritivo de forragem de A. latifolia, A. punctata e A. tristis, tendo como padrão Lotus corniculatus (cornichão e L. uliginosus. O ensaio foi realizado em casa de vegetação durante 210 dias (4000 graus-dia. A disponibilidade de forragem (DF foi similar entre A. latifolia (276 g MS/m² e cornichão (275 g MS/m² e entre A. tristis (201g MS/m² e L. uliginosus (192 g MS/m², sendo que A. punctata apresentou a menor DF (155 g MS/m². A. latifolia caracterizou-se pela maior precocidade na DF, devido ao crescimento mais rápido em relação às demais espécies, sugerindo seu potencial para utilização durante a estação fria. Em relação às análises de qualidade, o teor de proteína bruta (PB nas folhas de A. latifolia foi de até 21,6% e a DIVMO atingiu 72,3%. Os maiores conteúdos de PB e DIVMO foram encontrados nas folhas de cornichão, 30,3 e 75,8%, respectivamente. A. tristis apresentou DIVMO muito baixa nos caules (34,9 a 44,7%, o que poderia limitar seu consumo por bovinos. Concluiu-se que, entre as espécies de Adesmia estudadas, A. latifolia detém o maior potencial forrageiro, sugerindo a continuidade de estudos com a espécie.The genus Adesmia DC. has 17 species native to Brazil, distributed in the Southern states, whose importance is linked to its adaptation to the soils and climatic conditions of the region, besides being an active winter-growing species (temperate. This work aimed to compare the patterns of dry matter (DM accumulation and nutritive value of A. latifolia, A. punctata and A. tristis, using Lotus corniculatus (birdsfoot trefoil and L. uliginosus (big trefoil, as checks. The experiment was carried out in

  10. EPR dosimetry in a mixed neutron and gamma radiation field.

    Science.gov (United States)

    Trompier, F; Fattibene, P; Tikunov, D; Bartolotta, A; Carosi, A; Doca, M C

    2004-01-01

    Suitability of Electron Paramagnetic Resonance (EPR) spectroscopy for criticality dosimetry was evaluated for tooth enamel, mannose and alanine pellets during the 'international intercomparison of criticality dosimetry techniques' at the SILENE reactor held in Valduc in June 2002, France. These three materials were irradiated in neutron and gamma-ray fields of various relative intensities and spectral distributions in order to evaluate their neutron sensitivity. The neutron response was found to be around 10% for tooth enamel, 45% for mannose and between 40 and 90% for alanine pellets according their type. According to the IAEA recommendations on the early estimate of criticality accident absorbed dose, analyzed results show the EPR potentiality and complementarity with regular criticality techniques.

  11. In Vivo Antiplasmodial Potentials of the Combinations of Four Nigerian Antimalarial Plants

    Directory of Open Access Journals (Sweden)

    Adeleke Clement Adebajo

    2014-08-01

    Full Text Available Various combinations of Nauclea latifolia root, Artocarpus altilis stem bark, Murraya koenigii leaf and Enantia chlorantha stem bark used in African ethnomedicine as decoctions for malaria and fevers, and combinations with standard drugs, were investigated for antiplasmodial activities using Plasmodium berghei berghei-infected mice. The respective prophylactic and curative ED50 values of 189.4 and 174.5 mg/kg for N. latifolia and chemosuppressive ED50 value of 227.2 mg/kg for A. altilis showed that they were the best antimalarial herbal drugs. A 1.6-fold increase of the survival time given by the negative control was elicited by M. koenigii, thereby confirming its curative activity. Pyrimethamine with an ED50 of 0.5 ± 0.1 mg/kg for the prophylactic, and chloroquine with ED50 = 2.2 ± 0.1 and 2.2 ± 0.0 mg/kg for the chemosuppressive and curative tests, respectively, were significantly (p < 0.05 more active. Co-administrations of N. latifolia with the standard drugs significantly reduced their prophylactic, chemosuppressive and curative actions, possibly increasing the parasites’ resistance. Binary combinations of N. latifolia or M. koenigii with any of the other plants significantly increased the prophylactic and suppressive activities of their individual plants, respectively. Also, E. chlorantha with A. altilis or N. latifolia enhanced their respective prophylactic or curative activities, making these combinations most beneficial against malaria infections. Combinations of three and four extracts gave varied activities. Hence, the results justified the combinations of ethnomedicinal plants in antimalarial herbal remedies and showed the importance of the three in vivo models in establishing antimalarial activity.

  12. Fate of heavy metals in vertical subsurface flow constructed wetlands treating secondary treated petroleum refinery wastewater in Kaduna, Nigeria.

    Science.gov (United States)

    Mustapha, Hassana Ibrahim; van Bruggen, J J A; Lens, P N L

    2018-01-02

    This study examined the performance of pilot-scale vertical subsurface flow constructed wetlands (VSF-CWs) planted with three indigenous plants, i.e. Typha latifolia, Cyperus alternifolius, and Cynodon dactylon, in removing heavy metals from secondary treated refinery wastewater under tropical conditions. The T. latifolia-planted VSF-CW had the best heavy metal removal performance, followed by the Cyperus alternifolius-planted VSF-CW and then the Cynodon dactylon-planted VSF-CW. The data indicated that Cu, Cr, Zn, Pb, Cd, and Fe were accumulated in the plants at all the three VSF-CWs. However, the accumulation of the heavy metals in the plants accounted for only a rather small fraction (0.09-16%) of the overall heavy metal removal by the wetlands. The plant roots accumulated the highest amount of heavy metals, followed by the leaves, and then the stem. Cr and Fe were mainly retained in the roots of T. latifolia, Cyperus alternifolius, and Cynodon dactylon (TF < 1), meaning that Cr and Fe were only partially transported to the leaves of these plants. This study showed that VSF-CWs planted with T. latifolia, Cyperus Alternifolius, and Cynodon dactylon can be used for the large-scale removal of heavy metals from secondary refinery wastewater.

  13. Effects of plant species on soil microbial processes and CH4 emission from constructed wetlands

    International Nuclear Information System (INIS)

    Wang, Yanhua; Yang, Hao; Ye, Chun; Chen, Xia; Xie, Biao; Huang, Changchun; Zhang, Jixiang; Xu, Meina

    2013-01-01

    Methane (CH 4 ) emission from constructed wetland has raised environmental concern. This study evaluated the influence of mono and polyculture constructed wetland and seasonal variation on CH 4 fluxes. Methane emission data showed large temporal variation ranging from 0 to 249.29 mg CH 4 m −2 h −1 . Results indicated that the highest CH 4 flux was obtained in the polyculture system, planted with Phragmites australis, Zizania latifolia and Typha latifolia, reflecting polyculture system could stimulate CH 4 emission. FISH analysis showed the higher amount of methanotrophs in the profile of Z. latifolia in both mono and polyculture systems. The highest methanogens amount and relatively lower methanotrophs amount in the profile of polyculture system were obtained. The results support the characteristics of CH 4 fluxes. The polyculture constructed wetland has the higher potential of global warming. -- Highlights: ► The polyculture constructed wetland has the higher contribution to CH 4 emission. ► The CH 4 –C conversion ranged from 0 to 3.7%. ► The Z. latifolia played important roles in methanotrophs growth and CH 4 consumption. ► Major influence of T-N, TOC and plant cover on CH 4 emission was obtained. -- The polyculture constructed wetland has the higher contribution to global warming

  14. Phytochemical profiles and antioxidant potential of four Arctic vascular plants from Svalbard

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, P.; Singh, S.M.; DeSouza, L.; Wahidullah, S.

    the chemical composition and antioxidative activities of four Arctic flowering plant species (Dryas octopetala, Carex rupestris, Silene uralensis and Deschampsia alpina.) through in vitro measurements of the free radical scavenging activities (FRS), inhibition...

  15. Peat as Substrate for Small-Scale Constructed Wetlands Polishing Secondary Effluents from Municipal Wastewater Treatment Plant

    Directory of Open Access Journals (Sweden)

    Meng Jin

    2017-11-01

    Full Text Available With the recent development of constructed wetland technology, it has become a mainstream treatment technology for the mitigation of a variety of wastewaters. This study reports on the treatment performance and pH attenuation capacity of three different configurations of small-scale on-site surface flow constructed wetlands (SFCW: T1 (Peat + Typha latifolia, T2 (T. latifolia alone, and T3 (Peat alone treating secondary effluent from the Amherstview Water Pollution Control Plant (WPCP for two treatment periods (start-up period and operational period. The aim of this study was to compare the nutrients removal efficiencies between the different treatments, as well as to evaluate the effects of substrate and vegetation on the wetland system. For a hydraulic retention time of 2.5 days, the results showed that all treatment systems could attenuate the pH level during both the start-up and operational periods, while significant nutrient removal performance could only be observed during the operational period. Peat was noted to be a better SFCW substrate in promoting the removal of nitrate (NO3-N, total nitrogen (TN, and phosphorus. The addition of T. latifolia further enhanced NO3-N and TN removal efficiencies, but employing T. latifolia alone did not yield effluents that could meet the regulatory discharge limit (1.0 mg/L for phosphorus.

  16. Chemical analysis of bioactive substances in seven siberian Saussurea species

    Science.gov (United States)

    Avdeeva, Elena; Reshetov, Yaroslav; Shurupova, Margarita; Zibareva, Larisa; Borisova, Evgeniia; Belousov, Mikhail

    2017-11-01

    Main groups of biologically active substances of seven siberian Saussurea species (S. controversa DC., S. latifolia Ledeb., S. parviflora (Poir.) DC., S. frolowii Ledeb, S. amara (L.) DC., S. salicifolia (L.) DC. and S. daurica Adams) have been studied using paper, thin-layer, performance liquid chromatography, IR spectroscopy, spectrophotometry and mass spectrometry with inductively coupled plasma. Siberian Saussurea species have a rich elemental composition and contain a variety of phenolic compounds, amino acids, polysaccharides. The majority of polysaccharides are accumulated by S. controversa, S. salicifolia and S. frolowii. These plants contain a significant amount of calcium that may be a species characteristic. All plants contain quercetin and its glycosides, in some species luteolin, kaempferol, glycosides of apigenin and myricetin were revealed. Phenolic acids with predominant content of caffeic, chlorogenic and cinnamic acids were found in all the species. The maximum amount of phenolic acids and flavonoids was determined in the grass of S. latifolia, S. controversa and S. daurica. Characteristic absorption bands of lactone carbonyl of sesquiterpenoids in IR spectrum found in S. latifolia, S. controversa, S. daurica, S. amara and S. salicifolia. HPLC / UV analysis showed that peaks with absorption maxima of 242-246 nm due to the presence of α,β-unsaturated ketone group in the structure of ecdysteroids were found in S. salicifolia, S. controversa, S. daurica and S. latifolia.

  17. The composition and depth of green roof substrates affect the growth of Silene vulgaris and Lagurus ovatus species and the C and N sequestration under two irrigation conditions.

    Science.gov (United States)

    Ondoño, S; Martínez-Sánchez, J J; Moreno, J L

    2016-01-15

    Extensive green roofs are used to increase the surface area covered by vegetation in big cities, thereby reducing the urban heat-island effect, promoting CO2 sequestration, and increasing biodiversity and urban-wildlife habitats. In Mediterranean semi-arid regions, the deficiency of water necessitates the use in these roofs of overall native plants which are more adapted to drought than other species. However, such endemic plants have been used scarcely in green roofs. For this purpose, we tested two different substrates with two depths (5 and 10 cm), in order to study their suitability with regard to adequate plant development under Mediterranean conditions. A compost-soil-bricks (CSB) (1:1:3; v:v:v) mixture and another made up of compost and bricks (CB) (1:4; v:v) were arranged in two depths (5 and 10 cm), in cultivation tables. Silene vulgaris (Moench) Garcke and Lagurus ovatus L. seeds were sown in each substrate. These experimental units were subjected, on the one hand, to irrigation at 40% of the registered evapotranspiration values (ET0) and, on the other, to drought conditions, during a nine-month trial. Physichochemical and microbiological substrate characteristics were studied, along with the physiological and nutritional status of the plants. We obtained significantly greater plant coverage in CSB at 10 cm, especially for L. ovatus (80-90%), as well as a better physiological status, especially in S. vulgaris (SPAD values of 50-60), under irrigation, whereas neither species could grow in the absence of water. The carbon and nitrogen fixation by the substrate and the aboveground biomass were also higher in CSB at 10 cm, especially under L. ovatus - in which 1.32 kg C m(-2) and 209 g N m(-2) were fixed throughout the experiment. Besides, the enzymatic and biochemical parameters assayed showed that microbial activity and nutrient cycling, which fulfill a key role for plant development, were higher in CSB. Therefore, irrigation of 40% can

  18. A Regional Guidebook for Applying the Hydrogeomorphic Approach to Assessing Wetland Functions of Prairie Potholes

    Science.gov (United States)

    2006-05-01

    glyptosperma ribseed sandmat 0 Euphorbia maculata Spotted Spurge 0 Euthamia graminifolia Flat-top Goldentop 6 Fragaria virginiana Wild Strawberry 4...Foxtail UK Setaria viridis Pennisetum viridis Green Foxtail 0 Silene sp. Catchfly UK Sisyrinchium campestre White-eyed Grass 10 Sium suave

  19. Wild vegetable mixes sold in the markets of Dalmatia (southern Croatia

    Directory of Open Access Journals (Sweden)

    Łuczaj Łukasz

    2013-01-01

    Full Text Available Abstract Background Dalmatia is an interesting place to study the use of wild greens as it lies at the intersection of influence of Slavs, who do not usually use many species of wild greens, and Mediterranean culinary culture, where the use of multiple wild greens is common. The aim of the study was to document the mixtures of wild green vegetables which are sold in all the vegetable markets of Dalmatia. Methods All vendors (68 in all 11 major markets of the Dalmatian coast were interviewed. The piles of wild vegetables they sold were searched and herbarium specimens taken from them. Results The mean number of species in the mix was 5.7. The most commonly sold wild plants are: Sonchus oleraceus L., Allium ampeloprasum L., Foeniculum vulgare Mill., Urospermum picroides F.W.Schmidt, Papaver rhoeas L., Daucus carota L., Taraxacum sp., Picris echioides L., Silene latifolia Poir. and Crepis spp. Also the cultivated beet (Beta vulgaris L. and a few cultivated Brassicaceae varieties are frequent components. Wild vegetables from the mix are usually boiled for 20–30 minutes and dressed with olive oil and salt. Altogether at least 37 wild taxa and 13 cultivated taxa were recorded. Apart from the mixes, Asparagus acutifolius L. and Tamus communis L. shoots are sold in separate bunches (they are usually eaten with eggs, as well as some Asteraceae species, the latter are eaten raw or briefly boiled. Conclusions The rich tradition of eating many wild greens may result both from strong Venetian and Greek influences and the necessity of using all food resources available in the barren, infertile land in the past. Although the number of wild-collected green vegetables is impressive we hypothesize that it may have decreased over the years, and that further in-depth local ethnobotanical studies are needed in Dalmatia to record the disappearing knowledge of edible plants.

  20. Karyotype of some Thai Hypoxidaceae species

    Directory of Open Access Journals (Sweden)

    Ladda Eksomtramage

    2013-08-01

    Full Text Available Somatic chromosome numbers and karyotypes of nine species in three genera of Thai Hypoxidaceae were determinedin root tips. All species are diploid with 2n = 18 and asymmetrical karyotypes including metacentric (m submetacentric (smsubtelocentric (st and also telocentric (t in some species. Satellite chromosomes (SAT were observed in all species studiedexcept in C. latifolia. The karyotypes of Curculigo ensifolia 4m+8sm+6st(2SAT, C. latifolia 2m+14sm+2st, C. megacarpa2m+12sm+4st(2SAT, C. villosa 4m+10sm(2SAT+4st, Hypoxis aurea 2m+8sm+8st(2SAT, Molineria capitulata 2m+10sm+2st (2SAT+4t, M. trichocarpa 2m+10sm+6st(2SAT, M. gracilis and M. latifolia 4m+8sm+4st (2SAT+2t are reported forthe first time. The chromosome relative length of Curculigo, Hypoxis and Molineria range between 3.44-9.55, 4.03-8.12 and3.64-8.97, respectively.

  1. Use of cattails in treating wastewater from a Pb/Zn mine

    Science.gov (United States)

    Lan, Chongyu; Chen, Guizhu; Li, Liuchun; Wong, M. H.

    1992-01-01

    This article describes the use of a combined treatment system, which includes an aquatic treatment pond with Typha latifolia Linn. (Typhaceae) as the dominant species and a stabilization pond, to treat the wastewater from a Pn/Zn mine at Shaoguan, Guangdong Province, China. In 1983, it was noted that T. latifolia bloomed in areas affected by the wastewater emitted from the mine, hence a combined purification system was subsequently built. The influent contained high levels of total suspended solids (4635 mg/liter), chemical oxygen demand (14.5 mg/liter) as well as Pb (1.6 mg/liter) and Zn (1.9 mg/liter). The results of the effluent after treatment showed that the total suspended solids, chemical oxygen demand, Pb, and Zn had been reduced by 99%, 55%, 95%, and 80% respectively. The results of plant tissue analysis indicled that T. latifolia assimilated significant amounts of Pb and Zn, especially in the root portion. During 1986 several species of algae and fish were present in the pond, usually with a higher density in areas containing lower metal concentrations in the water.

  2. Lead, zinc and cadmium accumulation from two metalliferous soils with contrasting calcium contents in hyperaccumulating and non-hyperaccumulating metallophytes: a comparative study.

    NARCIS (Netherlands)

    Mohtadi, A.; Ghaderian, S.M.; Schat, H.

    2012-01-01

    Aims and background: We previously compared metallicolous (M) and non-metallicolous (NM) populations of Noccaea (=Thlaspi) caerulescens, Silene vulgaris, and Matthiola flavida for their abilities to tolerate and (hyper)-accumulate lead (Pb) in hydroponics. In the present study we aimed 1) to check

  3. Adjuvants for single droplet application of glyphosate

    DEFF Research Database (Denmark)

    Mathiassen, Solvejg Kopp; Kudsk, Per; Lund, Ivar

    2016-01-01

    Retention and biological activity of droplets of glyphosate deposited onto plant leaves using a Drop on Demand inkjet printer application system, was examined on pot-grown Brassica napus, Solanum nigrum, Chenopodium album, Silene noctiflora and Echinocloa crus-galli plants. Retention was measured...

  4. Komponen minyak atsiri dari daun tiga jenis tumbuhan famili Myrtaceae asal Desa Soa dan Desa Sota Merauke

    Directory of Open Access Journals (Sweden)

    Yuliasri Jamal

    1997-12-01

    Full Text Available An isolation of the leaves of Asteromyrtus sp., Melaleuca leucaleucadendron, M.angustifolia and M.leucadendon Var. latifolia by steam distillation yielded 1.36, 1.02, 1.32 and 0.97 % essential oils respectively. Their constituents were analyzed using two combination techniques, gas chromathography and mass spectroscophy (GCMS. Based on their compositin, the essensial oils of Asteromyrtus sp., Melaleuca leucaleucadendron, M.angustifolia were considered acceptable for commercial essential oil production because of their potential source of cineole (65.11, 60.03. 82.43 % respectively, while M.leucadendon Var. latifolia was vey interesting source of methyleugenol (97.03% which attractant activity.

  5. Typha latifolia L. Türünün Farklı Kısımlarındaki Ağır Metal ve Makro Element Miktarlarının Karşılaştırılması

    Directory of Open Access Journals (Sweden)

    Fatih KARAHASAN

    2015-09-01

    Full Text Available In this study, we determined the accumulation of heavy metals (Cu, Zn, Fe, Cd, Pb, Mn and the concentrations of macroelements (N, P, K, Ca, Mg, Na in root, steam, rhizome and leaf parts in Typha latifolia L. disturbed in Melet, Turnasuyu and Akçaova aquatic ecosystems in Ordu province. According to the analyzes, the amounts of heavy metal and macro elements of plant parts are N>P> K>N>Ca>Mg>Zn>Fe>Mn>Pb>Cd>Cu for the steam, N>P>K>Ca>Mg>Fe>Na>Mn> Zn>Pb>Cd>Cu for the root, N>P>K>Ca>Mg>Na>Mn>Zn>Fe>Pb>Cd>Cu for the leaves and N>P>K>Ca>Mg>Na>Fe>Zn>Mn>Pb>Cd>Cu for the rhizome. Our data is evaluated by using three-ways analysis of variance. According to variance analyses, we found significant statistical differences among overall average of factor levels for the elements Iron (Fe, Phosphorus (P and Magnesium (Mg (p<0.05 and/or p<0.01. While a triple interactions are found significant for Zinc (Zn and Nitrogen (N elements, various binary interactions are found for Copper (Cu, Cadmium (Cd, Lead (Pb, Manganese (Mn, Potassium (K, Calcium (Ca and Sodium (Na elements (p<0.05 and/or p<0.01

  6. Status and limiting factors of two rare plant species in dry montane communities of Hawai`i Volcanoes National Park.

    Science.gov (United States)

    Pratt, Linda W.; VanDeMark, Joshua R.; Euaparadorn, Melody

    2012-01-01

    Two rare plants native to montane dry forests and woodland communities of Hawai`i Volcanoes National Park (HAVO) were studied for more than two years to determine their stand structure, short-term mortality rates, patterns of reproductive phenology, success of fruit production, floral visitor composition, seed germination rates in the greenhouse, and survival of both natural and planted seedlings. Phyllostegia stachyoides, a shrubby Hawaiian mint (Lamiaceae) that is a species of concern, was studied within two small kīpuka at a natural population on the park’s Mauna Loa Strip, and three plantings at sites along the Mauna Loa Road were also monitored. Silene hawaiiensis, a threatened shrub species in the pink family (Caryophyllaceae), was monitored at two natural populations, one on Mauna Loa at the Three Trees Kīpuka and the second on Kīlauea Crater Rim south of Halema`uma`u. Silene hawaiiensis plantings were also made inside and outside ungulate exclosures at the park’s Kahuku Unit

  7. Ecological half-life of 137Cs in plants associated with a contaminated stream

    International Nuclear Information System (INIS)

    Peles, John D.; Smith, Michael H.; Lehr Brisbin, I.

    2002-01-01

    Ecological half-life (T e ) is a useful measure for studying the long-term decline of contaminants, such as radionuclides, in natural systems. The current investigation determined levels of radiocesium ( 137 Cs) in two aquatic (Polygonum punctatum, Sagittaria latifolia) and three terrestrial (Alnus serrulata, Myrica cerifera, Salix nigra) plant species from a contaminated stream and floodplain on the U.S. Department of Energy's Savannah River Site. Current 137 Cs levels in plants were used in conjunction with historical data to determine T e of 137 Cs in each species. Median concentrations of 137 Cs were highest in S. latifolia (0.84 Bq g -1 ) and lowest in M. cerifera (0.10 Bq g -1 ). T e 's ranged from 4.85 yr in M. cerifera to 8.35 yr in S. nigra, both terrestrial species. T e 's for all aquatic (6.30 yr) and all terrestrial (5.87) species combined were very similar. The T e 's of the two aquatic primary producers (P. punctatum and S. latifolia) in the Steel Creek ecosystem were somewhat longer than T e values previously reported for some consumers from this ecosystem

  8. Shortening the juvenile phase for flowering

    NARCIS (Netherlands)

    Higazy, M.K.M.T.

    1962-01-01

    Higazy tried to determine whether the duration of the juvenile phase for flowering was a fixed character or whether it could be influenced by external growth factors.

    Lunaria biennis was chosen as a cold-requiring biennial, Silene armeria as a long-day plant and Salvia

  9. 7 CFR 301.32-2 - Regulated articles.

    Science.gov (United States)

    2010-01-01

    ... jambhiri Lemon, Rough Mediterranean. Citrus latifolia Lime, Persian Oriental. Citrus limon Lemon..., Oriental. Citrus reticulata x C. sinensis = Citrus nobilis Orange, king Mediterranean, Melon, Oriental...

  10. Investigation on concentration of elements in wetland sediments and aquatic plants

    Directory of Open Access Journals (Sweden)

    H. Janadeleh

    2016-01-01

    Full Text Available The major aim of the present study was to investigate element (Fe, Ni, Pb, V, Zn concentrations in sediment and different tissues of Phragmities australis and Typha latifolia in Hor al-Azim Wetland Southwest Iran. Sampling of sediments and aquatic plants was carried out during spring and summer 2014. Results showed that the mean  concentrations of elements in Phragmities australis  in root and stem-leaf were as follows: Iron:4448 mg/kg, Nickel: 28 mg/kg, Lead:8 mg/kg, Vanadium:10 mg/kg  and Zinc 15.5 mg/kg in root and: Fe:645 mg/kg, Ni:15 mg/kg, Pb:4 mg/kg, V:4 mg/kg and Zinc 16 mg/kg respectively. Also, the mean concentrations of Fe, Ni, Pb, V and Zn in roots of Typha latifolia were 8696 mg/kg, 34 mg/kg, 5 mg/kg, 19 mg/kg and 27 mg/kg respectively. The mean concentrations of Fe, Ni, V, Pb, Zn in stem-leaves of Typha latifolia were as follows: 321 mg/kg, 3 mg/kg, 7 mg/kg, 2 mg/kg and 14 mg/kg respectively. The mean concentrations of Fe, Ni, V, Pb and zinc were as: 40991 mg/kg, 65 mg/kg, 60 mg/kg, 31 mg/kg, 60 mg/kg respectively in surface sediment of study area. Concentration pattern of elements in sediment were as: Fe>Ni>Zn>V>Pb. The highest concentration of elements in the plant was seen in the roots. Also, Typha latifolia can uptake more concentration of elements than Phragmities australis. Based on the enrichment factor, Ni in summer had the highest EF values among the elements studied and it has a moderate enrichment.

  11. Morphoagronomic genetic diversity in american wild rice species

    Directory of Open Access Journals (Sweden)

    Elizabeth Ann Veasey

    2008-02-01

    Full Text Available To characterize the genetic variability among species and populations of South American wild rice, eleven populations of Oryza glumaepatula, seven of O. grandiglumis, four of O. latifolia and one of O. alta, from Brazil and Argentina, were evaluated. A greenhouse experiment was conducted in completely randomized blocks with 23 treatments. Twenty morphoagronomic traits were assessed. Univariate analyses were performed with 16 quantitative traits with the partitioning of populations within species. Significant differences (pVisando caracterizar a diversidade genética entre espécies e populações de arroz selvagem da América do Sul, foram avaliadas 11 populações de Oryza glumaepatula, sete de O. grandiglumis, quatro de O. latifolia e uma população de O. alta, originárias do Brasil e Argentina. Foi conduzido um experimento em casa-de-vegetação em blocos ao acaso com 23 tratamentos. Vinte caracteres agro-morfológicos foram avaliados. Análises univariadas foram realizadas para 16 caracteres quantitativos, desdobrando-se o efeito de populações dentro de espécies. Diferenças significativas (p<0,001 entre espécies foram observadas para todos os caracteres bem como entre populações dentro de espécies. A mais variável foi O. glumaepatula seguida de O. latifolia. Análises de agrupamento e discriminante canônica confirmaram a separação das populações de O. glumaepatula das espécies tetraplóides, e a grande variação genética entre populações de O. latifolia. Diferenças morfológicas entre as três espécies tetraplóides parecem suficientes para classificá-las como espécies pelo menos na condição statu nascendi.

  12. Electron/electron acoustic instability

    International Nuclear Information System (INIS)

    Gary, S.P.

    1987-01-01

    The electron acoustic wave becomes a normal mode of an unmagnetized collisionless plasma in the presence of two electron components with similar densities, but strongly disparate temperatures. The characteristic frequency of this mode is the plasma frequency of the cooler electron component. If these two electron components have a relative drift speed several times the thermal speed of the cooler component, the electron/electron acoustic instability may arise. This paper describes the parametric dependences of the threshold drift speed and maximum growth rate of this instability, and compares these with the same properties of the electron/ion acoustic instability. Under the condition of zero current, the electron/ion acoustic instability typically has the lower threshold drift speed, so that observation of the electron/electron acoustic instability is a strong indication of the presence of an electrical current in the plasma

  13. Remediation of mercury-polluted soils using artificial wetlands.

    Science.gov (United States)

    García-Mercadoa, Héctor Daniel; Fernándezb, Georgina; Garzón-Zúñigac, Marco Antonio; Durán-Domínguez-de-Bazúaa, María Del Carmen

    2017-01-02

    Mexico's mercury mining industry is important for economic development, but has unfortunately contaminated soils due to open-air disposal. This case was seen at two sites in the municipality of Pinal de Amoles, State of Queretaro, Mexico. This paper presents an evaluation of mercury dynamics and biogeochemistry in two soils (mining waste soil) using ex-situ wetlands over 36 weeks. In soils sampled in two former mines of Pinal de Amoles, initial mercury concentrations were 424 ± 29 and 433 ± 12 mg kg -1 in La Lorena and San Jose, former mines, respectively. Typha latifolia and Phragmites australis were used and 20 reactors were constructed (with and without plants). The reactors were weekly amended with a nutrient solution (NPK), for each plant, at a pH of 5.0. For remediation using soils from San Jose 70-78% of mercury was removed in T. latifolia reactors and 76-82% in P. australis reactors, and for remediation of soils from La Lorena, mercury content was reduced by 55-71% using T. latifolia and 58-66% in P. australis reactors. Mercury emissions into the atmosphere were estimated to be 2-4 mg m -2 h -1 for both soils.

  14. Electronics and electronic systems

    CERN Document Server

    Olsen, George H

    1987-01-01

    Electronics and Electronic Systems explores the significant developments in the field of electronics and electronic devices. This book is organized into three parts encompassing 11 chapters that discuss the fundamental circuit theory and the principles of analog and digital electronics. This book deals first with the passive components of electronic systems, such as resistors, capacitors, and inductors. These topics are followed by a discussion on the analysis of electronic circuits, which involves three ways, namely, the actual circuit, graphical techniques, and rule of thumb. The remaining p

  15. Electrons, Electronic Publishing, and Electronic Display.

    Science.gov (United States)

    Brownrigg, Edwin B.; Lynch, Clifford A.

    1985-01-01

    Provides a perspective on electronic publishing by distinguishing between "Newtonian" publishing and "quantum-mechanical" publishing. Highlights include media and publishing, works delivered through electronic media, electronic publishing and the printed word, management of intellectual property, and recent copyright-law issues…

  16. Rocky Flats Neutron Detector Testing at Valduc, France

    International Nuclear Information System (INIS)

    Kim, S.S.; Dulik, G.M.

    2011-01-01

    Recent program requirements of the US Department of Energy/NNSA have led to a need for a criticality accident alarm system to be installed at a newly activated facility. The Criticality Safety Group of the Lawrence Livermore National Laboratory (LLNL) was able to recover and store for possible future use approximately 200 neutron criticality detectors and 20 master alarm panels from the former Rocky Flats Plant in Golden, Colorado when the plant was closed. The Criticality Safety Group participated in a facility analysis and evaluation, the engineering design and review process, as well as the refurbishment, testing, and recalibration of the Rocky Flats criticality alarm system equipment to be used in the new facility. In order to demonstrate the functionality and survivability of the neutron detectors to the effects of an actual criticality accident, neutron detector testing was performed at the French CEA Valduc SILENE reactor from October 7 to October 19, 2010. The neutron detectors were exposed to three criticality events or pulses generated by the SILENE reactor. The first excursion was performed with a bare or unshielded reactor, and the second excursion was made with a lead shielded/reflected reactor, and the third excursion with a polyethylene reflected core. These tests of the Rocky Flats neutron detectors were performed as a part of the 2010 Criticality Accident Alarm System Benchmark Measurements at the SILENE Reactor. The principal investigators for this series of experiments were Thomas M. Miller and John C. Wagner of the Oak Ridge National Laboratory, with Nicolas Authier and Nathalie Baclet of CEA Valduc. Several other organizations were also represented, including the Y-12 National Security Complex, Lawrence Livermore National Laboratory, Los Alamos National Laboratory, CEA Saclay, and Babcock International Group.

  17. Electron-electron Bremsstrahlung for bound target electrons

    International Nuclear Information System (INIS)

    Haug, E.

    2008-01-01

    For the process of electron-electron (e-e) Bremsstrahlung the momentum and energy distributions of the recoiling electrons are calculated in the laboratory frame. In order to get the differential cross section and the photon spectrum for target electrons which are bound to an atom, these formulae are multiplied by the incoherent scattering function and numerically integrated over the recoil energy. The effect of atomic binding is most pronounced at low energies of the incident electrons and for target atoms of high atomic numbers. The results are compared to those of previous calculations. (authors)

  18. Étude de l'activité antibactérienne des huiles essentielles de ...

    African Journals Online (AJOL)

    SARAH

    31 juil. 2014 ... J. Appl. Biosci. 2014. Étude de l'activité antibactérienne des huiles essentielles de Teucrium capitatium L et l'extrait de Siléne vulgaris sur différentes souches testées. 7482. Study the antibacterial activity of essential oils Teucrium capitatium L and Silene vulgaris extract on different strains tested. Abstract:.

  19. Interplay between electron-phonon and electron-electron interactions

    International Nuclear Information System (INIS)

    Roesch, O.; Gunnarsson, O.; Han, J.E.; Crespi, V.H.

    2005-01-01

    We discuss the interplay between electron-electron and electron-phonon interactions for alkali-doped fullerides and high temperature superconductors. Due to the similarity of the electron and phonon energy scales, retardation effects are small for fullerides. This raises questions about the origin of superconductivity, since retardation effects are believed to be crucial for reducing effects of the Coulomb repulsion in conventional superconductors. We demonstrate that by treating the electron-electron and electron-phonon interactions on an equal footing, superconductivity can be understood in terms of a local pairing. The Jahn-Teller character of the important phonons in fullerides plays a crucial role for this result. To describe effects of phonons in cuprates, we derive a t-J model with phonons from the three-band model. Using exact diagonalization for small clusters, we find that the anomalous softening of the half-breathing phonon as well as its doping dependence can be explained. By comparing the solution of the t-J model with the Hartree-Fock approximation for the three-band model, we address results obtained in the local-density approximation for cuprates. We find that genuine many-body results, due to the interplay between the electron-electron and electron-phonon interactions, play an important role for the the results in the t-J model. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Acute and Sub-Acute Toxicity of Aqueous Extract of Nauclea ...

    African Journals Online (AJOL)

    Keywords: Nauclea latifolia, Renal excretion, Hematological parameters, Biomarkers, Allergy,. Inflammation, Diuretic ... long-term and low-dose exposures to human are subject is highly ... with standard feed in solid (balls). The animals.

  1. An ethnobotany of the Lukomir Highlanders of Bosnia & Herzegovina.

    Science.gov (United States)

    Ferrier, Jonathan; Saciragic, Lana; Trakić, Sabina; Chen, Eric C H; Gendron, Rachelle L; Cuerrier, Alain; Balick, Michael J; Redžić, Sulejman; Alikadić, Emira; Arnason, John T

    2015-11-25

    This aim of this study is to report upon traditional knowledge and use of wild medicinal plants by the Highlanders of Lukomir, Bjelašnica, Bosnia and Herzegovina (B&H). The Highlanders are an indigenous community of approximately 60 transhumant pastoralist families who speak Bosnian (Bosanski) and inhabit a highly biodiverse region of Europe. This paper adds to the growing record of traditional use of wild plants within isolated communities in the Balkans. An ethnobotanical study using consensus methodology was conducted in Lukomir in Bjelašnica's mountains and canyons. Field work involved individual semi-structured interviews during which informants described plants, natural product remedies, and preparation methods on field trips, garden tours, while shepherding, or in settings of their choice. Plant use categories were ranked with informant consensus factor and incorporated into a phylogenetic tree. Plants cited were compared to other ethnobotanical surveys of the country. Twenty five people were interviewed, resulting in identification of 58 species (including two subspecies) from 35 families, which were cited in 307 medicinal, 40 food, and seven material use reports. Individual plant uses had an average consensus of five and a maximum consensus of 15 out of 25. There were a number of rare and endangered species used as poisons or medicine that are endemic to Flora Europaea and found in Lukomir. Ten species (including subspecies) cited in our research have not previously been reported in the systematic ethnobotanical surveys of medicinal plant use in B&H: (Elymus repens (L.) Gould, Euphorbia myrsinites L., Jovibarba hirta (L.) Opiz, Lilium bosniacum (Beck) Fritsch, Matricaria matricarioides (Less.) Porter ex Britton, Phyllitis scolopendrium (L.) Newman, Rubus saxatilis L., Silene uniflora Roth ssp. glareosa (Jord.) Chater & Walters, Silene uniflora Roth ssp. prostrata (Gaudin) Chater & Walters, Smyrnium perfoliatum L.). New uses not reported in any of the

  2. In vivo screening and evaluation of four herbs against MRSA infections.

    Science.gov (United States)

    Arshad, Najma; Mehreen, Arifa; Liaqat, Iram; Arshad, Muhammad; Afrasiab, Humera

    2017-11-23

    Recently, we reported high in vitro antibacterial efficacy of Althaea officinalis, Ziziphus jujuba, Cordia latifolia and Thymus vulgaris out of a total 21 plants against wide range of bacteria including MRSA. This study was therefore, designed to confirm efficacy of these four herbs against MRSA in an animal model. A pilot study was conducted to establish the dose of S. aureus (KY698020) required to induce clinical infection. Afterword, in main trial, efficacy of aforementioned plant extracts on the course of sore throat was checked by evaluating general health, gross lesion score, bacterial load and hematology in mice. Pilot study revealed that 40 μl dose of 10 7  CFU/ml could induce infection which persist upto 08 days post infection. Mice treated with T. vulgaris and Z. jujuba showed reduction in gross lesion score of both heart and lungs. Treatment with only some plants could significantly decrease bacterial load of throat (T. vulgaris) heart, blood and joint (C. latifolia, and T. vulagris). Hematological indicators confirmed in vivo control of MRSA infection in all treatment groups except A. officinalis. This is first report confirming in vivo anti-MRSA potential of C. latifolia and T. vulgaris and highlight the need to explore bioactive constituents of these plants. Moreover, previously reported in vitro antibacterial efficiency of A. officinalis could not be validated in current study.

  3. Bioremediation studies of tailing ponds of uranium mines

    International Nuclear Information System (INIS)

    Sudhakar, G.; Muralidhar Rao, C.; Swaminathan, Siva Kumar

    2012-01-01

    A study was undertaken for three years to evaluate the potential of native plant species for the phytoremediation of tailing ponds of Uranium mines, Jaduguda, Jharkhand. Five sampling stations: three at Jaduguda (TP1, TP2, and TP3), one at Turamdih (TTP) and one at Effluent Treatment Plant (ETP) were selected. pH, Electrical conductivity (EC), 12 metals (- AI, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Cd, Pb) and 3 radionuclides - Co, Sr and U) were analysed. From the analysis of sediment/soil/water/effluent of tailing ponds, 4 elements - U, Mn, AI and Fe were found to be significantly in higher concentrations in water, and 8-elements (U, Mn, V, Fe, Ni, Cu and Zn) were found to be in higher concentrations in soils. U and Mn were found to be the predominant contaminants. 26 plant species were screened for their ability to accumulate and remediate the contaminated soils of which only four plant species - one fern (Pteris vittata - P. vittata), one terrestrial (Saccharum spontaneum - S. spontaneum ) and two aquatic species (Typha latifolia - T. latifolia, Cyperus compressus - C. compressus) were shortlisted for phytoremediation studies in laboratory condition and transfer factors were calculated. The results of the study under controlled conditions indicate that P. vittata, S. spontaneum, T. latifolia and C. compressus were found to be the candidate species for phytoremediation of Uranium mine tailings. (author)

  4. Electronic emission and electron guns

    International Nuclear Information System (INIS)

    Roy, Amitava

    2010-01-01

    This paper reviews the process of electron emission from metal surface. Although electrons move freely in conductors like metals, they normally do not leave the metal without some manipulation. In fact, heating and bombardment are the two primary ways in which electrons are emitted through the use of a heating element behind the cathode (termed thermionic emission) or as a result of bombardment with a beam of electrons, ions, or metastable atoms (termed secondary emission). Another important emission mechanism called Explosive Electron Emission (EEE) is also often used in various High Voltage Pulse Power Systems to generate very high current (few hundreds of kA) pulsed electron beams. The electron gun is the device in that it shoots off a continuous (or pulsed) stream of electrons. A brief idea about the evolution of the electron gun components and their basis of functioning are also discussed. (author)

  5. Evaluation and comparison of polyphenols and bioactivities of wild edible fruits of North-West Himalaya, India

    Directory of Open Access Journals (Sweden)

    Himani Singh

    2015-11-01

    Full Text Available Objective: To evaluate and compare the polyphenol contents, antioxidant, anti-elastase, anti-collagenase, anti-tyrosinase and anti-inflammatory activities of 13 wild edible fruits [Pyracantha crenulata, Berberis asiatica (B. asiatica, Ficus subincisa (F. subincisa, Morus serrata, Ziziphus nummularia, Leea asiatica (L. asiatica, Dendrobenthamia capitata, Ziziphus mauritiana, Prunus cerasoides, Ampelocissus latifolia (A. latifolia, Vitis jacquemontii, Morus alba and Grewia optiva] of North-West Himalayan Region of India. Methods: Fruits extracts were prepared with 80% aqueous acetone and evaluated for total phenolic contents (TPC and total flavonoid contents (TFC. Free radical scavenging activities [against 1,1-diphenyl-2-picryl-hydrazyl, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid, linoleate hydroperoxyl and superoxide radicals], ferric reducing ability, ferrous metal chelating capacity, anti-elastase, anti-collagenase, anti-tyrosinase and anti-inflammatory activities were determined by using various in vitro assays. Results: TPC varied from 58.83 to 4 496.39 mg gallic acid equivalents/100 g fruit weight (FW, being highest in A. latifolia and lowest in F. subincisa. TFC ranged from 108.00 to 1 963.75 mg catechin equivalents/100 g FW, standing highest in L. asiatica and lowest in Prunus cerasoides. A. latifolia and L. asiatica possessed the highest antioxidant activities while B. asiatica and L. asiatica owned uppermost anti-elastase and anti-collagenase activities, respectively. B. asiatica revealed the highest anti-tyrosinase activity and F. subincisa demonstrated the highest antiinflammatory activity. The present study revealed differential contribution of TPC and TFC in various antioxidant activities. However, no obvious relationship was visible between antielastase/anti-collagenase/anti-tyrosinase/anti-inflammatory activities and TPC/TFC, suggesting the role of individual or combination of specific phenolics and flavonoids

  6. Born-Oppenheimer Dynamics, Electronic Friction, and the Inclusion of Electron-Electron Interactions

    Science.gov (United States)

    Dou, Wenjie; Miao, Gaohan; Subotnik, Joseph E.

    2017-07-01

    We present a universal expression for the electronic friction as felt by a set of classical nuclear degrees of freedom (DOFs) coupled to a manifold of quantum electronic DOFs; no assumptions are made regarding the nature of the electronic Hamiltonian and electron-electron repulsions are allowed. Our derivation is based on a quantum-classical Liouville equation for the coupled electronic-nuclear motion, followed by an adiabatic approximation whereby electronic transitions are assumed to equilibrate faster than nuclear movement. The resulting form of friction is completely general, but does reduce to previously published expressions for the quadratic Hamiltonian (i.e., Hamiltonians without electronic correlation). At equilibrium, the second fluctuation-dissipation theorem is satisfied and the frictional matrix is symmetric. To demonstrate the importance of electron-electron correlation, we study electronic friction within the Anderson-Holstein model, where a proper treatment of electron-electron interactions shows signatures of a Kondo resonance and a mean-field treatment is completely inadequate.

  7. Phytophthora obscura sp. nov., a new species of the novel Phytophthora subclade 8d

    Science.gov (United States)

    N. J. Grünwald; S. Werres; E. M. Goss; C. R. Taylor; V. J. Fieland

    2012-01-01

    A new Phytophthora species was detected (i) in the USA, infecting foliage of Kalmia latifolia, (ii) in substrate underneath Pieris, and (iii) in Germany in soil samples underneath Aesculus hippocastanum showing disease symptoms. The new...

  8. Use of Strategic Placement of Dredged Sediments to Support Horseshoe Island in the Atchafalaya River, Louisiana: A Preliminary Ecological Survey

    Science.gov (United States)

    2014-08-01

    cowpea (Vigna luteola), broadleaf cattail (Typha latifolia), invasive Chinese tallowtree (Triadica sebifera), rosemallow (Hibiscus lasiocarpos), and...Benth. hairypod cowpea Fabaceae N Vigna unguiculata (L.) Walp. cowpea Fabaceae - Hydrilla verticillata (L. f.) Royle waterthyme Hydrocharitaceae I

  9. The antibacterial potentials of Nauclea latifolia

    African Journals Online (AJOL)

    STORAGESEVER

    2008-05-16

    May 16, 2008 ... traditional Chinese medicine, Indian ayurveda and Arabic unani medicine, and to various forms of indigenous medicine (WHO, 1978). Historically, plant has provided a good source of anti-infective agents; emetine, quinine and berberine remain highly effective instruments in the fight against microbial ...

  10. The antibacterial potentials of Nauclea latifolia

    African Journals Online (AJOL)

    STORAGESEVER

    2008-05-16

    May 16, 2008 ... Ibom and Cross River State of Nigeria and also in most parts of the ... laboratory Technology, Vom and the Bacterial research Laboratory,. National ... With the aid of a sterile wire loop, colonies of fresh cultures of the different ..... sanguinolenta Extract. Proc. Int. syp. On East – West Med. Seoul, korea: ...

  11. Secondary metabolites from Scorzonera latifolia roots

    Czech Academy of Sciences Publication Activity Database

    Acikara, O. B.; Šmejkal, K.; Cvačka, Josef; Buděšínský, Miloš; Dračínský, Martin; Saltan, G.

    2015-01-01

    Roč. 81, č. 16 (2015), PM167 ISSN 0032-0943. [GA 2015. International Congress and Annual Meeting of the Society for Medicinal Plant and Natural Product Research /63./. 23.08.2015-27.08.2015, Budapest] Institutional support: RVO:61388963 Keywords : medical plant * metabolites * Asteraceae Subject RIV: CB - Analytical Chemistry, Separation

  12. GLOBAL JOURNAL OF AGRICULTURAL SCIENCES ISSN 1596-2903

    African Journals Online (AJOL)

    Ada Global

    semi-hardwood and softwood) of the stem cuttings of G. latifolia in relation to ... second week after planting even though softwood cuttings started earlier showed the importance of carbohydrate ..... women in the University of Nigeria, Nsukka.

  13. Potential for phosphate mitigation from agricultural runoff by three aquatic macrophytes

    Science.gov (United States)

    Phosphate from agricultural runoff is considered a contributor to eutrophication. Three aquatic macrophyte species, Leersia oryzoides, Typha latifolia, and Sparganium americanum, were investigated for their phosphate mitigation ability. Mesocosms were exposed to flowing phosphate enriched water (1...

  14. Acute and Sub-Acute Toxicity of Aqueous Extract of Nauclea ...

    African Journals Online (AJOL)

    Tropical Journal of Pharmaceutical Research January 2014; 13 (1): 109-115 ... Purpose: To determine the dose – toxicity profile of the aqueous extract of Nauclea latifolia stem bark. (AQE). ... cause single-strand breaks in liver, kidney and.

  15. Criticality accident studies and methodology implemented at the CEA

    International Nuclear Information System (INIS)

    Barbry, Francis; Fouillaud, Patrick; Reverdy, Ludovic; Mijuin, Dominique

    2003-01-01

    Based on the studies and results of experimental programs performed since 1967 in the CRAC, then SILENE facilities, the CEA has devised a methodology for criticality accident studies. This methodology integrates all the main focuses of its approach, from criticality accident phenomenology to emergency planning and response, and thus includes aspects such as criticality alarm detector triggering, airborne releases, and irradiation risk assessment. (author)

  16. Dicty_cDB: Contig-U12284-1 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available nogaster LD14594 fu... 185 3e-45 AF107797_1( AF107797 |pid:none) Capronia mansonii DNA-dependent RN... 185 3...1( AF107798 |pid:none) Capronia pilosella DNA-dependent R... 120 9e-26 AJ634168_1( AJ634168 |pid:none) Silen..._1( AY699223 |pid:none) Musa velutina RNA polymerase II se... 120 9e-26 AF107798_

  17. In vitro placental self and cross pollination in some species

    Directory of Open Access Journals (Sweden)

    Azza Shehata

    2014-01-01

    Full Text Available Excised placentae with ovules of Primula pubescens, P. auricula, Scopolia carniolica, Digitalis purpurea, Torenia fournieri and Chionodoxa luciliae were self pollinated in vitro and the development of seeds was observed. The same method was used for obtaining hybrid globular embryos from crosses between: P. pubescens x P. auricula, Scopolia carniolica x Physochlaina praealta, Melandrium album x Silene saxifraga and M. album x Arenaria pungens.

  18. Epigenetic regulation of photoperiodic flowering

    OpenAIRE

    Takeno, Kiyotoshi

    2010-01-01

    The cytidine analogue 5-azacytidine, which causes DNA demethylation, induced flowering in the non-vernalization-requiring plants Perilla frutescens var. crispa, Silene armeria and Pharbitis nil (synonym Ipomoea nil) under non-inductive photoperiodic conditions, suggesting that the expression of photoperiodic flowering-related genes is regulated epigenetically by DNA methylation. The flowering state induced by DNA demethylation was not heritable. Changes in the genome-wide methylation state we...

  19. Effective electron-electron and electron-phonon interactions in the Hubbard-Holstein model

    International Nuclear Information System (INIS)

    Aprea, G.; Di Castro, C.; Grilli, M. . E-mail marco.grilli@roma1.infn.it; Lorenzana, J.

    2006-01-01

    We investigate the interplay between the electron-electron and the electron-phonon interaction in the Hubbard-Holstein model. We implement the flow-equation method to investigate within this model the effect of correlation on the electron-phonon effective coupling and, conversely, the effect of phonons in the effective electron-electron interaction. Using this technique we obtain analytical momentum-dependent expressions for the effective couplings and we study their behavior for different physical regimes. In agreement with other works on this subject, we find that the electron-electron attraction mediated by phonons in the presence of Hubbard repulsion is peaked at low transferred momenta. The role of the characteristic energies involved is also analyzed

  20. 21 CFR 184.1333 - Gum ghatti.

    Science.gov (United States)

    2010-04-01

    ... the bark of Anogeissus latifolia, a large tree found in the dry deciduous forests of India and Ceylon... percent). (3) Loss on drying. Not more than 14 percent dried at 105 °C for 5 hours. (4) Identification...

  1. Copepoda: Pandaridae

    African Journals Online (AJOL)

    1991-03-04

    ,27(1) finely striated marginal membrane is present along the anterior and lateral margins of the cephalothorax of D. latifolia (Figure 1 & 4c), which no doubt fonns an effective seal against the host tissue. Posteriorly, however ...

  2. Electron-electron coincidence spectroscopies at surfaces

    International Nuclear Information System (INIS)

    Stefani, G.; Iacobucci, S.; Ruocco, A.; Gotter, R.

    2002-01-01

    In the past 20 years, a steadily increasing number of electron-electron coincidence experiments on atoms and molecules have contributed to a deeper understanding of electron-electron correlation effects. In more recent years this technique has been extended to the study of solid surfaces. This class of one photon IN two electrons OUT experiments will be discussed with an emphasis on grazing incidence geometry, that is expected to be particularly suited for studying surfaces. The crucial question of which is the dominant mechanism that leads to ejection of pairs of electron from the surface will be addressed. It will be shown that, depending on the kinematics chosen, the correlated behaviour of the pairs of electrons detected might be singled out from independent particle one

  3. Electron distribution function in electron-beam-excited plasmas

    International Nuclear Information System (INIS)

    Brau, C.A.

    1976-01-01

    In monatomic plasmas excited by high-intensity relativistic electron beams, the electron secondary distribution function is dominated by elastic electron-electron collisions at low electron energies and by inelastic electron-atom collisions at high electron energies (above the excitation threshold). Under these conditions, the total rate of excitation by inelastic collisions is limited by the rate at which electron-electron collisions relax the distribution function in the neighborhood of the excitation threshold. To describe this effect quantitatively, an approximate analytic solution of the electron Boltzmann equation is obtained, including both electron-electron and inelastic collisions. The result provides a simple formula for the total rate of excitation

  4. Semiochemical -Based Communication in interspecific interactions between IPS PINI and Pityogenes Knecteli (Swaine) (Coleoptera: Scolytidae) in Lodgepole Pine

    Science.gov (United States)

    Therese M. Poland; John H. Borden

    1994-01-01

    The pine engraver, Ips pini Say, and Pityogenes knechteli Swaine often co-exist in lodgepole pine, Pinus contorta var. latifolia Engelmann. We tested the hypotheses that P. knechteli produces an attractive pheromone and that the attraction of P. knechteli...

  5. Hard electronics; Hard electronics

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    Hard material technologies were surveyed to establish the hard electronic technology which offers superior characteristics under hard operational or environmental conditions as compared with conventional Si devices. The following technologies were separately surveyed: (1) The device and integration technologies of wide gap hard semiconductors such as SiC, diamond and nitride, (2) The technology of hard semiconductor devices for vacuum micro- electronics technology, and (3) The technology of hard new material devices for oxides. The formation technology of oxide thin films made remarkable progress after discovery of oxide superconductor materials, resulting in development of an atomic layer growth method and mist deposition method. This leading research is expected to solve such issues difficult to be easily realized by current Si technology as high-power, high-frequency and low-loss devices in power electronics, high temperature-proof and radiation-proof devices in ultimate electronics, and high-speed and dense- integrated devices in information electronics. 432 refs., 136 figs., 15 tabs.

  6. Women's Involvement in Non Timber Forest Products Utilization in ...

    African Journals Online (AJOL)

    Vitellaria paradoxa, Parkia biglobosa and Prosopis africana were more important for food and income while Nauclea latifolia, Khaya senegalensis ranked highest for medicine. Woody plants preferred as fuel wood included; Parkia biglobosa, Brachystegia eurycoma and Bridelia feruginea. Community Forest Programmes ...

  7. Electron radiography

    Science.gov (United States)

    Merrill, Frank E.; Morris, Christopher

    2005-05-17

    A system capable of performing radiography using a beam of electrons. Diffuser means receive a beam of electrons and diffuse the electrons before they enter first matching quadrupoles where the diffused electrons are focused prior to the diffused electrons entering an object. First imaging quadrupoles receive the focused diffused electrons after the focused diffused electrons have been scattered by the object for focusing the scattered electrons. Collimator means receive the scattered electrons and remove scattered electrons that have scattered to large angles. Second imaging quadrupoles receive the collimated scattered electrons and refocus the collimated scattered electrons and map the focused collimated scattered electrons to transverse locations on an image plane representative of the electrons' positions in the object.

  8. Aportaciones a la flora de Galicia, VIII

    OpenAIRE

    Gómez Vigide, F.; García Martínez, X.R.; Silva Pando, F.J.; González Domínguez, J.; Blanco Dios, J.B.; Rodríguez González, A.; Rial Pousa, S.; Álvarez Graña, D.; Caamaño Portela, J.L.; Pino Pérez, J.J.; Pino Pérez, R.

    2006-01-01

    Se citan 37 plantas de variado interés para la flora gallega. Se incluyen 8 novedades de carácter regional (Pteris incompleta Cav., Potentilla recta L., Myriophyllum spicatum L., Solanum sisymbrifolium Lam., Knautia integrifolia (L.) Bertol., Senecio inaequidens DC. Melica arrecta G. Kunze y Stipa clausa Trab.), 17 novedades provinciales (Vandenboschia speciosa (Willd.) G. Kunkel, Ranunculus bupleuroides Brot., Silene niceensis All., Armeria transmontana (Samp.) Lawr., Alcea rosea...

  9. Electron transfer from electronic excited states to sub-vacuum electron traps in amorphous ice

    International Nuclear Information System (INIS)

    Vichnevetski, E.; Bass, A.D.; Sanche, L.

    2000-01-01

    We investigate the electron stimulated yield of electronically excited argon atoms (Ar * ) from monolayer quantities of Ar deposited onto thin films of amorphous ice. Two peaks of narrow width ( - electron-exciton complex into exciton states, by the transfer of an electron into a sub-vacuum electron state within the ice film. However, the 10.7 eV feature is shifted to lower energy since electron attachment to Ar occurs within small pores of amorphous ice. In this case, the excess electron is transferred into an electron trap below the conduction band of the ice layer

  10. Monte Carlo study of electron relaxation in graphene with spin polarized, degenerate electron gas in presence of electron-electron scattering

    Science.gov (United States)

    Borowik, Piotr; Thobel, Jean-Luc; Adamowicz, Leszek

    2017-12-01

    The Monte Carlo simulation method is applied to study the relaxation of excited electrons in monolayer graphene. The presence of spin polarized background electrons population, with density corresponding to highly degenerate conditions is assumed. Formulas of electron-electron scattering rates, which properly account for electrons presence in two energetically degenerate, inequivalent valleys in this material are presented. The electron relaxation process can be divided into two phases: thermalization and cooling, which can be clearly distinguished when examining the standard deviation of electron energy distribution. The influence of the exchange effect in interactions between electrons with parallel spins is shown to be important only in transient conditions, especially during the thermalization phase.

  11. Phytochemical, elemental and biotechnological study of Cryptocarya ...

    African Journals Online (AJOL)

    Materials and Methods: The secondary metabolites from the leaves and fruits of C. latifolia were extracted using solvents of various polarities, isolated using column chromatography and identified using spectroscopic techniques. The in vitro free radical scavenging activity (antioxidant capacity) of selected phytocompounds ...

  12. Criticality accident studies and research performed in the Valduc criticality laboratory, France

    International Nuclear Information System (INIS)

    Barbry, F.; Fouillaud, P.

    2001-01-01

    In 1967, the IPSN (Institut de Protection et de Surete Nucleaire - Nuclear Protection and Safety Institute) started studies and research in France on criticality accidents, with the objective of improving knowledge and modelling of accidents in order to limit consequences to the public, the environment and installations. The criticality accident is accompanied by an intense emission of neutronic and gamma radiation and releases of radioactive products in the form of gas and aerosols, generating irradiation and contamination risks. The main objectives of the studies carried out, particularly using the CRAC installation and the SILENE reactor at Valduc (France), were to model the physics of criticality accidents, to estimate the risks of irradiation and radioactive releases, to elaborate an accident detection system and to provide information for intervention plans. This document summarizes the state of knowledge in the various fields mentioned above. The results of experiments carried out in the Valduc criticality laboratory are used internationally as reference data for the qualification of calculation codes and the assessment of the consequences of a criticality accident. The SILENE installation, that reproduces the various conditions encountered during a criticality accident, is also a unique international research tool for studies and training on those matters. (author)

  13. Iridoids as chemical markers of false ipecac (Ronabea emetica), a previously confused medicinal plant.

    Science.gov (United States)

    Berger, Andreas; Fasshuber, Hannes; Schinnerl, Johann; Robien, Wolfgang; Brecker, Lothar; Valant-Vetschera, Karin

    2011-12-08

    Several roots or rhizomes of rubiaceous species are reportedly used as the emetic and antiamoebic drug ipecac. True ipecac (Carapichea ipecacuanha) is chemically well characterized, in contrast to striated or false ipecac derived from the rhizomes of Ronabea emetica (syn. Psychotria emetica). Besides its previous use as substitute of ipecac, the latter species is applied in traditional medicine of Panama and fruits of its relative Ronabea latifolia are reported as curare additives from Colombia. Compounds of Ronabea emetica were isolated using standard chromatographic techniques, and structurally characterized by NMR spectroscopy and mass spectrometry. Organ specific distribution in Ronabea emetica as well as in Ronabea latifolia was further assessed by comparative HPLC analysis. Four iridoid-glucosides, asperuloside (1), 6α-hydroxygeniposide (2), deacetylasperulosidic acid (3) and asperulosidic acid (4) were extracted from leaves of Ronabea emetica. Rhizomes, used in traditional medicine, were dominated by 3. HPLC profiles of Ronabea latifolia were largely corresponding. These results contrast to the general tendency of producing emetine-type and indole alkaloids in species of Psychotria and closely related genera and merit chemotaxonomic significance, characterizing the newly delimited genus Ronabea. The aim of the work was to resolve the historic problem of adulteration of ipecac by establishing the chemical profile of Ronabea emetica, the false ipecac, as one of its less known sources. The paper demonstrates that different sources of ipecac can be distinguished by their phytochemistry, thus contributing to identifying adulterations of true ipecac. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  14. Electron attachment cross sections obtained from electron attachment spectroscopy

    International Nuclear Information System (INIS)

    Popp, P.; Baumbach, J.I.; Leonhardt, J.W.; Mothes, S.

    1988-01-01

    Electron capture detectors have a high sensitivity for substances with high thermal electron attachment cross sections. The electron attachment spectroscopy makes it possible to change the mean electron energy in such a way that the maximum for dissociative electron attachment is reached. Thus, best operation modes of the detection system as well as significant dependencies of electron attachment coefficients are available. Cross sections for electron attachment as a function of the electron energy are obtained with the knowledge of electron energy distribution functions from Boltzmann equation analysis by a special computer code. A disadvantage of this electron attachment spectroscopy is the superposition of space charge effects due to the decrease of the electron drift velocity with increasing mean electron energy. These influences are discussed. (author)

  15. Electron beam effects in auger electron spectroscopy and scanning electron microscopy

    International Nuclear Information System (INIS)

    Fontaine, J.M.; Duraud, J.P.; Le Gressus, C.

    1979-01-01

    Electron beam effects on Si(100) and 5% Fe/Cr alloy samples have been studied by measurements of the secondary electron yield delta, determination of the surface composition by Auger electron spectroscopy and imaging with scanning electron microscopy. Variations of delta as a function of the accelerating voltage Esub(p) (0.5 -9 Torr has no effect on technological samples covered with their reaction layers; the sensitivities to the beam depend rather on the earlier mechanical, thermal and chemical treatment of the surfaces. (author)

  16. The effect of electron-electron interaction induced dephasing on electronic transport in graphene nanoribbons

    Energy Technology Data Exchange (ETDEWEB)

    Kahnoj, Sina Soleimani; Touski, Shoeib Babaee [School of Electrical and Computer Engineering, University of Tehran, P.O. Box 14395-515, Tehran (Iran, Islamic Republic of); Pourfath, Mahdi, E-mail: pourfath@ut.ac.ir, E-mail: pourfath@iue.tuwien.ac.at [School of Electrical and Computer Engineering, University of Tehran, P.O. Box 14395-515, Tehran (Iran, Islamic Republic of); Institute for Microelectronics, TU Wien, Gusshausstrasse 27–29/E360, 1040 Vienna (Austria)

    2014-09-08

    The effect of dephasing induced by electron-electron interaction on electronic transport in graphene nanoribbons is theoretically investigated. In the presence of disorder in graphene nanoribbons, wavefunction of electrons can set up standing waves along the channel and the conductance exponentially decreases with the ribbon's length. Employing the non-equilibrium Green's function formalism along with an accurate model for describing the dephasing induced by electron-electron interaction, we show that this kind of interaction prevents localization and transport of electrons remains in the diffusive regime where the conductance is inversely proportional to the ribbon's length.

  17. Electron Beam Generation in Tevatron Electron Lenses

    International Nuclear Information System (INIS)

    Kamerdzhiev, V.; Kuznetsov, G.; Shiltsev, V.; Solyak, N.; Tiunov, M.

    2006-01-01

    New type of high perveance electron guns with convex cathode has been developed. Three guns described in this article are built to provide transverse electron current density distributions needed for Electron Lenses for beam-beam compensation in the Tevatron collider. The current distribution can be controlled either by the gun geometry or by voltage on a special control electrode located near cathode. We present the designs of the guns and report results of beam measurements on the test bench. Because of their high current density and low transverse temperature of electrons, electron guns of this type can be used in electron cooling and beam-beam compensation devices

  18. Electron beam generation in Tevatron electron lenses

    International Nuclear Information System (INIS)

    Kamerdzhiev, V.; Kuznetsov, G.; Shiltsev, V.; Solyak, N.; Tiunov, M.

    2006-01-01

    New type of high perveance electron guns with convex cathode has been developed. Three guns described in this article are built to provide transverse electron current density distributions needed for Electron Lenses for beam-beam compensation in the Tevatron collider. The current distribution can be controlled either by the gun geometry or by voltage on a special control electrode located near cathode. We present the designs of the guns and report results of beam measurements on the test bench. Because of their high current density and low transverse temperature of electrons, electron guns of this type can be used in electron cooling and beam-beam compensation devices

  19. Electronic technology

    International Nuclear Information System (INIS)

    Kim, Jin Su

    2010-07-01

    This book is composed of five chapters, which introduces electronic technology about understanding of electronic, electronic component, radio, electronic application, communication technology, semiconductor on its basic, free electron and hole, intrinsic semiconductor and semiconductor element, Diode such as PN junction diode, characteristic of junction diode, rectifier circuit and smoothing circuit, transistor on structure of transistor, characteristic of transistor and common emitter circuit, electronic application about electronic equipment, communication technology and education, robot technology and high electronic technology.

  20. The Electron

    Energy Technology Data Exchange (ETDEWEB)

    Thomson, George

    1972-01-01

    Electrons are elementary particles of atoms that revolve around and outside the nucleus and have a negative charge. This booklet discusses how electrons relate to electricity, some applications of electrons, electrons as waves, electrons in atoms and solids, the electron microscope, among other things.

  1. Determination of the electron-electron collisional frequency by means of plasma electron spectroscopy

    International Nuclear Information System (INIS)

    Kolokolov, N.B.; Kudryavtsev, A.A.; Romanenko, V.A.

    1989-01-01

    Methods of controlling fast part of electron distribution function (DF) in nonlocal regime of current-free plasma are suggested and realized. Artificially created step in DF fast part has a simple link with frequencies of electron-electron and elastic electron-atom collisions that may be defined in the corresponding experiments

  2. Electron beam-plasma interaction and electron-acoustic solitary waves in a plasma with suprathermal electrons

    Science.gov (United States)

    Danehkar, A.

    2018-06-01

    Suprathermal electrons and inertial drifting electrons, so called electron beam, are crucial to the nonlinear dynamics of electrostatic solitary waves observed in several astrophysical plasmas. In this paper, the propagation of electron-acoustic solitary waves (EAWs) is investigated in a collisionless, unmagnetized plasma consisting of cool inertial background electrons, hot suprathermal electrons (modeled by a κ-type distribution), and stationary ions. The plasma is penetrated by a cool electron beam component. A linear dispersion relation is derived to describe small-amplitude wave structures that shows a weak dependence of the phase speed on the electron beam velocity and density. A (Sagdeev-type) pseudopotential approach is employed to obtain the existence domain of large-amplitude solitary waves, and investigate how their nonlinear structures depend on the kinematic and physical properties of the electron beam and the suprathermality (described by κ) of the hot electrons. The results indicate that the electron beam can largely alter the EAWs, but can only produce negative polarity solitary waves in this model. While the electron beam co-propagates with the solitary waves, the soliton existence domain (Mach number range) becomes narrower (nearly down to nil) with increasing the beam speed and the beam-to-hot electron temperature ratio, and decreasing the beam-to-cool electron density ratio in high suprathermality (low κ). It is found that the electric potential amplitude largely declines with increasing the beam speed and the beam-to-cool electron density ratio for co-propagating solitary waves, but is slightly decreased by raising the beam-to-hot electron temperature ratio.

  3. Taxonomic revision of the genus Microcos (Malvaceae-Grewioideae) in Peninsular Malaysia and Singapore

    NARCIS (Netherlands)

    Chung, R.C.K.; Soepadmo, E.

    2011-01-01

    A revision of the genus Microcos in Peninsular Malaysia and Singapore was conducted resulting in the recognition of twelve species. Six taxa (M. antidesmifolia var. antidesmifolia, M. fibrocarpa, M. lanceolata, M. latifolia, M. laurifolia and M. tomentosa) are common and occur more or less

  4. Do varying aquatic plant species affect phytoplankton and crustacean responses to a nitrogen-permethrin mixture?

    Science.gov (United States)

    Hydraulically connected wetland microcosms vegetated with either Typha latifolia or Myriophyllum aquaticum were amended with an NH4NO3 and permethrin mixture to assess the effectiveness of both plant species in mitigating ecological effects of the pollutant mixture on phytoplankton (as chlorophyll a...

  5. Global Journal of Pure and Applied Sciences - Vol 16, No 4 (2010)

    African Journals Online (AJOL)

    Antimicrobial activities of methanolic extract of Gongronema latifolia stem on clinical isolate of Escherichia coli from diarrhoea patients · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. EI Eze, EO Onu, CA Iwueze, GC Ugwu, 391-394 ...

  6. Origin, development, and impact of mountain laurel thickets on the mixed-oak forests of the central Appalachian Mountains, USA

    Science.gov (United States)

    Patrick H. Brose

    2016-01-01

    Throughout forests of the northern hemisphere, some species of ericaceous shrubs can form persistent understories that interfere with forest regeneration processes. In the Appalachian Mountains of eastern North America, mountain laurel (Kalmia latifolia) may interfere in the regeneration of mixed-oak (Quercus spp.) forests. To...

  7. An evaluation of seven methods for controlling mountain laurel thickets in the mixed-oak forests of the central Appalachian Mountains, USA

    Science.gov (United States)

    Patrick H. Brose

    2017-01-01

    In the Appalachian Mountains of eastern North America, mountain laurel (Kalmia latifolia) thickets in mixed-oak (Quercus spp.) stands can lead to hazardous fuel situations, forest regeneration problems, and possible forest health concerns. Therefore, land managers need techniques to control mountain laurel thickets and limit...

  8. Sementes nocivas que ocorreram em amostras de sementes de azevém (Lolium multiflorum, analisadas no Rio Grande do Sul nos anos de 1978 e 1979 Weed seeds in ryegrass seeds, analysed in Rio Grande do Sul, during 1978 and 1979

    Directory of Open Access Journals (Sweden)

    H. Giaretta

    1984-06-01

    Full Text Available Foram levantadas informações sobre a qualidade da semente de azevém utilizadas no Rio Grande do Sul e produzida no próprio Estado ou em outras uni dades da Federação e mesmo em outros Países, nos anos de 1978 e 1979. Estas informações foram obtidas através de fichas e Boletins de Análise de Sementes dos Laboratórios de Análise de Sementes (LAS do Rio Grande do Sul. Em 1978 analisou-se 2.319 t de azevém sendo 74% da semente oriunda do Rio Grande do Sul e 26% introduzida, enquanto que das 4.772 t analisadas em 1979 99,6% são do Rio Grande do Sul e 0,4% são introduzidas. O percentual de sementes de azevém, produzidas no Estado, contaminadas com sementes nocivas foi de 61,5% em 1978 e de 60,0% em 1979; e o de sementes int roduzidas no Estado foi de 45,6% em 1978 e de 29,4%em 1979. Foi observado que ent re as sementes originárias do RS destacaram -se com maior ocorrênci a em 1978 as espécies nocivas de Silene gallica, Setaria geniculata, Anthemis cotula, Digitaria adscendens e Echinochloa spp, enquanto que nas sementes int roduzidas desta caram-se Sida spp e Rumex spp; em 1979, na semente oriunda do Estado desta caram-se Amaranthus spp, Silene gallica e Setaria geniculata, enquanto que nas sementes introduzidas a maior ocorrência foi de Setaria geniculata, Echinochloa spp e Solanum spp.This paper presents a quality record of rye-grass seeds produced in Rio Grande do Sul or imported from other countries. It refers to the presence of weeds in ryegrass during 1978 and 1979. These record were obtained in the Analysis Bulletins at the Seed Analysis Laboratory of the Instituto de Pesquisas Agronômicas (IPAGRO Rio Grande do Sul°Brasil and in those from other institutions. This State produced 74% of 2.319 t analysed seeds and 26% come from other places in 1978. In 1979 4.772 t were registred, 99,6% from here and 0,4% from outside. The percentage of ryegrass seeds contaminated with weed seeds produced in the State, in 1978, were 61

  9. Enige diatomeeënsoorten, nieuw voor de Nederlandse flora

    NARCIS (Netherlands)

    Dam, van Herman

    1974-01-01

    During an investigation of the epiphyton, growing on the culms of Phragmites australis, Typha latifolia, and Glyceria maxima, in the nature-reserve “Het Naardermeer”, ten species of diatoms were discovered which are new for the Dutch flora. These are enumerated together with some notes on their

  10. Phylogeny and biogeography of North-American wild rice (Zizania L.Poaceae)

    Science.gov (United States)

    The wild-rice genus Zizania includes four species disjunctly distributed in eastern Asia and North America, with three species (Z. aquatica, Z. palustris, and Z. texana) in North America and one (Z. latifolia) in eastern Asia. The phylogeny and biogeography of Zizania were explored using sequences o...

  11. Aquatic Plant Control Research Program. Allelopathic Aquatic Plants for Aquatic Plant Management: A Feasibility Study

    Science.gov (United States)

    1989-10-01

    1978. " Ecotoxicology of aquatic plant communi- ties," Principles of Ecotoxicology , SCOPE Report 12, Chapter 11, pp 239-255. [Heavy metals, Pollutants...Phragmites communis and Equisetum limosum were cultivated . They found plant-plant influences depend on soil type. Typha latifolia, S. A2 lacustris, and

  12. Lodgepole pine provenances differ in chemical defense capacities against foliage and stem diseases

    Science.gov (United States)

    Maximization of lodgepole pine (Pinus contorta Douglas ex Louden var. latifolia Engelm. ex S. Watson) growth in the face of climate change and new pest outbreaks requires an understanding of the natural variability of quantitative resistance to disease. We assessed trees for the severity of foliar d...

  13. Response of Planted Eastern White Pine (Pinus strobus L.) to Mechanical Release, Competition, and Drought in the Southern Appalachians

    Science.gov (United States)

    Barton D. Clinton; Katherine J. Elliott; Wayne T. Swank

    1997-01-01

    Conversion of low-quality, natural mixed pine hardwood ecosystems, containing a mountain laurel (Kalmia latifolia L.) dominated understory, to more productive eastern white pine (Pinus strobus L.)/mixed-hardwood systems is a common prescription on relatively xeric southern Appalachian forest sites. We examined the effects of...

  14. Meiotic behavior of Adesmia DC. (Leguminosae-Faboideae species native to Rio Grande do Sul, Brazil

    Directory of Open Access Journals (Sweden)

    Coelho Liliana Gressler May

    1998-01-01

    Full Text Available Meiotic behavior in Adesmia DC. is described for the first time. The study encompassed twelve populations of seven Adesmia DC. species native to Rio Grande do Sul, Brazil. Populations with 2n = 2x = 20 are A. securigerifolia 9615, A. riograndensis 9590 (subnudae, A. latifolia 1568, 1775, 15025, A. bicolor JB-UFSM, A. incana var. incana 9636, 10288, A. punctata var. hilariana 6885, 10812, and A. tristis 10757. A. incana var. incana 9637 is a tetraploid with 2n = 4x = 40. The material was stained with 1% acetic orcein. The meiotic behavior of the populations studied was considered normal. The meiotic index (MI and the estimates of pollen grain viability were above 95%, except for A. latifolia 1568 (MI = 89%. The present data indicate that these plants are meiotically stable and potentially fertile, apparently with no problems for use in programs of selection, crossing and viable seed production.

  15. Electronic Government and Electronic Participation

    NARCIS (Netherlands)

    Tambouris, E; Scholl, H.J.; Janssen, M.F.W.H.A.; Wimmer, M.A.; Tarabanis, K; Gascó, M; Klievink, A.J.; Lindgren, I; Milano, M; Panagiotopoulos, P; Pardo, T.A.; Parycek, P; Sæbø, Ø

    2016-01-01

    Electronic government and electronic participation continue to transform the public sector and society worldwide and are constantly being transformed themselves by emerging information and communication technologies.This book presents papers from the 14th International Federation for Information

  16. Electronic Government and Electronic Participation

    NARCIS (Netherlands)

    Tambouris, E.; Scholl, H.J.; Janssen, M.F.W.H.A.; Wimmer, M.A.; Tarabanis, K.; Gascó, M.; Klievink, A.J.; Lindgren, I.; Milano, M.; Panagiotopoulos, P.; Pardo, T.A.; Parycek, P.; Sæbø, O.

    2015-01-01

    Electronic government and electronic participation continue to transform the public sector and society worldwide and are constantly being transformed themselves by emerging information and communication technologies. This book presents papers from the 14th International Federation for Information

  17. Electron detector

    International Nuclear Information System (INIS)

    Hashimoto, H.; Mogami, A.

    1975-01-01

    A device for measuring electron densities at a given energy level in an electron beam or the like having strong background noise, for example, in the detection of Auger electric energy spectrums is described. An electron analyzer passes electrons at the given energy level and at the same time electrons of at least one adjacent energy level. Detecting means associated therewith produce signals indicative of the densities of the electrons at each energy level and combine these signals to produce a signal indicative of the density of the electrons of the given energy level absent background noise

  18. Electron-electron interactions in artificial graphene

    Science.gov (United States)

    Rasanen, Esa

    2013-03-01

    Recent advances in the creation and modulation of graphenelike systems are introducing a science of ``designer Dirac materials.'' In its original definition, artificial graphene is a man-made nanostructure that consists of identical potential wells (quantum dots) arranged in an adjustable honeycomb lattice in the two-dimensional electron gas. As our ability to control the quality of artificial graphene samples improves, so grows the need for an accurate theory of its electronic properties, including the effects of electron-electron interactions. Here we determine those effects on the band structure and on the emergence of Dirac points, and discuss future investigations and challenges in this field.

  19. Decal electronics for printed high performance cmos electronic systems

    KAUST Repository

    Hussain, Muhammad Mustafa

    2017-11-23

    High performance complementary metal oxide semiconductor (CMOS) electronics are critical for any full-fledged electronic system. However, state-of-the-art CMOS electronics are rigid and bulky making them unusable for flexible electronic applications. While there exist bulk material reduction methods to flex them, such thinned CMOS electronics are fragile and vulnerable to handling for high throughput manufacturing. Here, we show a fusion of a CMOS technology compatible fabrication process for flexible CMOS electronics, with inkjet and conductive cellulose based interconnects, followed by additive manufacturing (i.e. 3D printing based packaging) and finally roll-to-roll printing of packaged decal electronics (thin film transistors based circuit components and sensors) focusing on printed high performance flexible electronic systems. This work provides the most pragmatic route for packaged flexible electronic systems for wide ranging applications.

  20. Electron-beam-induced-current and active secondary-electron voltage-contrast with aberration-corrected electron probes

    Energy Technology Data Exchange (ETDEWEB)

    Han, Myung-Geun, E-mail: mghan@bnl.gov [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Garlow, Joseph A. [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Materials Science and Engineering Department, Stony Brook University, Stony Brook, NY 11794 (United States); Marshall, Matthew S.J.; Tiano, Amanda L. [Department of Chemistry, Stony Brook University, Stony Brook, NY 11974 (United States); Wong, Stanislaus S. [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States); Department of Chemistry, Stony Brook University, Stony Brook, NY 11974 (United States); Cheong, Sang-Wook [Department of Physics and Astronomy, Rutgers Center for Emergent Materials, Rutgers University, Piscataway, NJ 08854 (United States); Walker, Frederick J.; Ahn, Charles H. [Department of Applied Physics and Center for Research on Interface Structures and Phenomena, Yale University, New Haven, CT 06520 (United States); Department of Mechanical Engineering and Materials Science, Yale University, New Haven, CT 06520 (United States); Zhu, Yimei [Condensed Matter Physics & Materials Science, Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2017-05-15

    Highlights: • Electron-beam-induced-current (EBIC) and active secondary-electron voltage-contrast (SE-VC) are demonstrated in STEM mode combined with in situ electrical biasing in a TEM. • Electrostatic potential maps in ferroelectric thin films, multiferroic nanowires, and single crystals obtained by off-axis electron holography were compared with EBIC and SE-VC data. • Simultaneous EBIC and active SE-VC performed with atomic resolution STEM are demonstrated. - Abstract: The ability to map out electrostatic potentials in materials is critical for the development and the design of nanoscale electronic and spintronic devices in modern industry. Electron holography has been an important tool for revealing electric and magnetic field distributions in microelectronics and magnetic-based memory devices, however, its utility is hindered by several practical constraints, such as charging artifacts and limitations in sensitivity and in field of view. In this article, we report electron-beam-induced-current (EBIC) and secondary-electron voltage-contrast (SE-VC) with an aberration-corrected electron probe in a transmission electron microscope (TEM), as complementary techniques to electron holography, to measure electric fields and surface potentials, respectively. These two techniques were applied to ferroelectric thin films, multiferroic nanowires, and single crystals. Electrostatic potential maps obtained by off-axis electron holography were compared with EBIC and SE-VC to show that these techniques can be used as a complementary approach to validate quantitative results obtained from electron holography analysis.

  1. Electronic Commerce and Electronic Business

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    This special issue is motivated by the recent upsurge of research activity in the areas of electronic commerce and electronic business both in India and all over the world. The current ... Monte Carlo methods for pricing financial options are then.

  2. Electron optical characteristics of a concave electrostatic electron mirror for a scanning electron microscope

    International Nuclear Information System (INIS)

    Hamarat, R.T.; Witzani, J.; Hoerl, E.M.

    1984-08-01

    Numerical computer calculations are used to explore the design characteristics of a concave electrostatic electron mirror for a mirror attachment for a conventional scanning electron microscope or an instrument designed totally as a scanning electron mirror microscope. The electron paths of a number of set-ups are calculated and drawn graphically in order to find the optimum shape and dimensions of the mirror geometry. This optimum configuration turns out to be the transition configuration between two cases of electron path deflection, towards the optical axis of the system and away from it. (Author)

  3. Electronic processes in organic electronics bridging nanostructure, electronic states and device properties

    CERN Document Server

    Kudo, Kazuhiro; Nakayama, Takashi; Ueno, Nobuo

    2015-01-01

    The book covers a variety of studies of organic semiconductors, from fundamental electronic states to device applications, including theoretical studies. Furthermore, innovative experimental techniques, e.g., ultrahigh sensitivity photoelectron spectroscopy, photoelectron yield spectroscopy, spin-resolved scanning tunneling microscopy (STM), and a material processing method with optical-vortex and polarization-vortex lasers, are introduced. As this book is intended to serve as a textbook for a graduate level course or as reference material for researchers in organic electronics and nanoscience from electronic states, fundamental science that is necessary to understand the research is described. It does not duplicate the books already written on organic electronics, but focuses mainly on electronic properties that arise from the nature of organic semiconductors (molecular solids). The new experimental methods introduced in this book are applicable to various materials (e.g., metals, inorganic and organic mater...

  4. African Journal of Biotechnology - Vol 11, No 87 (2012)

    African Journals Online (AJOL)

    Potential of a polyculture of Arundo donax and Typha latifolia for growth and phytotreatment of wastewater pollution · EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Soulwène Kouki, Neila Saidi, Asma Ben Rajeb, Fadhel M'hiri, 15341-15352 ...

  5. Effects of bark beetle attack on canopy fuel flammability and crown fire potential in lodgepole pine and Engelmann spruce forests

    Science.gov (United States)

    Wesley G. Page; Martin E. Alexander; Michael J. Jenkins

    2015-01-01

    Large wildland fires in conifer forests typically involve some degree of crowning, with their initiation and propagation dependent upon several characteristics of the canopy fuels. Recent outbreaks of mountain pine beetle (Dendroctonus ponderosae Hopkins) in lodgepole pine (Pinus contorta Dougl. var. latifolia E ngelm.) forests and spruce beetle (Dendroctonus...

  6. Tree regeneration and future stand development after bark beetle infestation and harvesting in Colorado lodgepole pine stands

    Science.gov (United States)

    Byron J. Collins; Charles C. Rhoades; Robert M. Hubbard; Michael A. Battaglia

    2011-01-01

    In the southern Rocky Mountains, current mountain pine beetle (Dendroctonus ponderosae Hopkins) outbreaks and associated harvesting have set millions of hectares of lodgepole pine (Pinus contorta var. latifolia Engelm. ex Wats.) forest onto new stand development trajectories. Information about immediate, post-disturbance tree regeneration will provide insight on...

  7. Post-harvest seedling recruitment following mountain pine beetle infestation of Colorado lodgepole pine stands: A comparison using historic survey records

    Science.gov (United States)

    Byron J. Collins; Charles C. Rhoades; Jeffrey Underhill; Robert M. Hubbard

    2010-01-01

    The extent and severity of overstory lodgepole pine (Pinus contorta var. latifolia Engelm. ex Wats.) mortality from mountain pine beetle (Dendroctonus ponderosae Hopkins) has created management concerns associated with forest regeneration, wildfire risk, human safety, and scenic, wildlife, and watershed resources in western North America. Owing to the unprecedented...

  8. Callus formation impedes adventitious rhizogenesis in air layers of broadleaved tree species

    Directory of Open Access Journals (Sweden)

    Sanjay Singh

    2014-07-01

    Full Text Available Callusing and root induction in air layering was evaluated aiming at evolution of procedure for mass clonal propagation of mature ortets of five tropical broadleaf species differing in their potential for adventitious root formation in shoot cuttings as: Anogiessus latifolia < Boswellia serrata < Dalbergia latifolia < Gmelina arborea < Dalbergia sissoo. Two experiments were conducted in rainy season during consecutive years; without application of growth regulators in the first year and with growth regulators (T1 - water, T2- 100 ppm indole-3-acetic acid, T3-100 ppm thiamine-HCl and T4 -combination of T2 + T3 in the next year. Air layered branches were detached from the trees to record percentage of alive airlayers, callusing and rooting (% as well as root number and root length. Response to air layering was found to be highly variable in five tree species but appeared to be feasible procedure for clonal propagation of mature ortets of B. serrata and D. sissoo with 100% (in auxin + thiamine treatment and 83.3% (in auxin treatment success, respectively. Maximum callusing (% was found in D. latifolia while no callusing was observed in D. sissoo, which is most easy-to-root among all five species. Callus formation impedes adventitious rhizogenesis in air layers as significant negative correlation of callusing (% and adventitious root formation was recorded in air layers of five tropical broadleaved tree species. Application of exogenous auxin alone or in combination with thiamine circumvents callusing to ensure direct development of roots for successful air layering.

  9. Decal electronics for printed high performance cmos electronic systems

    KAUST Repository

    Hussain, Muhammad Mustafa; Sevilla, Galo Torres; Cordero, Marlon Diaz; Kutbee, Arwa T.

    2017-01-01

    High performance complementary metal oxide semiconductor (CMOS) electronics are critical for any full-fledged electronic system. However, state-of-the-art CMOS electronics are rigid and bulky making them unusable for flexible electronic applications

  10. Precession mechanism of spin relaxation at frequent electron-electron collisions

    CERN Document Server

    Glazov, M M

    2002-01-01

    It is shown that the spin relaxation mechanism in the two-dimensional electron gas, is controlled not only through the electron pulse relaxation processes, determining the mobility, but through the electron-electron collisions as well. It is decided to use the kinetic equation, describing the electron spin mixing in the k-space, for determining the spin relaxation time tau sub s at frequent electron-electron collisions. The tau sub s time is calculated for the nondegenerated electron gas both with an account and with no account of the exchange interaction

  11. Practical electronics handbook

    CERN Document Server

    Sinclair, Ian R

    2013-01-01

    Practical Electronics Handbook, Third Edition provides the frequently used and highly applicable principles of electronics and electronic circuits.The book contains relevant information in electronics. The topics discussed in the text include passive and active discrete components; linear and digital I.C.s; microprocessors and microprocessor systems; digital-analogue conversions; computer aids in electronics design; and electronic hardware components.Electronic circuit constructors, service engineers, electronic design engineers, and anyone with an interest in electronics will find the book ve

  12. Composition quantification of electron-transparent samples by backscattered electron imaging in scanning electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Müller, E., E-mail: erich.mueller@kit.edu; Gerthsen, D.

    2017-02-15

    The contrast of backscattered electron (BSE) images in scanning electron microscopy (SEM) depends on material parameters which can be exploited for composition quantification if some information on the material system is available. As an example, the In-concentration in thin In{sub x}Ga{sub 1−x}As layers embedded in a GaAs matrix is analyzed in this work. The spatial resolution of the technique is improved by using thin electron-transparent specimens instead of bulk samples. Although the BSEs are detected in a comparably small angular range by an annular semiconductor detector, the image intensity can be evaluated to determine the composition and local thickness of the specimen. The measured intensities are calibrated within one single image to eliminate the influence of the detection and amplification system. Quantification is performed by comparison of experimental and calculated data. Instead of using time-consuming Monte-Carlo simulations, an analytical model is applied for BSE-intensity calculations which considers single electron scattering and electron diffusion. - Highlights: • Sample thickness and composition are quantified by backscattered electron imaging. • A thin sample is used to achieve spatial resolution of few nanometers. • Calculations are carried out with a time-saving electron diffusion model. • Small differences in atomic number and density detected at low electron energies.

  13. Nonlinear electron-acoustic rogue waves in electron-beam plasma system with non-thermal hot electrons

    Science.gov (United States)

    Elwakil, S. A.; El-hanbaly, A. M.; Elgarayh, A.; El-Shewy, E. K.; Kassem, A. I.

    2014-11-01

    The properties of nonlinear electron-acoustic rogue waves have been investigated in an unmagnetized collisionless four-component plasma system consisting of a cold electron fluid, non-thermal hot electrons obeying a non-thermal distribution, an electron beam and stationary ions. It is found that the basic set of fluid equations is reduced to a nonlinear Schrodinger equation. The dependence of rogue wave profiles on the electron beam and energetic population parameter are discussed. The results of the present investigation may be applicable in auroral zone plasma.

  14. Electron-cyclotron-resonant-heated electron distribution functions

    International Nuclear Information System (INIS)

    Matsuda, Y.; Nevins, W.M.; Cohen, R.H.

    1981-01-01

    Recent studies at Lawrence Livermore National Laboratory (LLNL) with a bounce-averaged Fokker-Planck code indicate that the energetic electron tail formed by electron-cyclotron resonant heating (ECRH) at the second harmonic is not Maxwellian. We present the results of our bounce-averaged Fokker-Planck code along with some simple analytic models of hot-electron distribution functions

  15. Predicting lodgepole pine site index from climatic parameters in Alberta.

    Science.gov (United States)

    Robert A. Monserud; Shongming Huang; Yuqing. Yang

    2006-01-01

    We sought to evaluate the impact of climatic variables on site productivity of lodgepole pine (Pinus contorta var. latifolia Engelm.) for the province of Alberta. Climatic data were obtained from the Alberta Climate Model, which is based on 30-year normals from the provincial weather station network. Mapping methods were based...

  16. Effect of feeding some evergreen tropical browse plant leaves on ...

    African Journals Online (AJOL)

    A feeding trial was conducted with thirty (30) weaner rabbits to investigate the nutritive potentials of some evergreen tropical browse plant leaves (Ficcus thoningii, Vitex doniana, Daniela oliveri, Sarcocephalus latifolia). Mixed breed rabbits were used and randomly assigned to five (5) treatments (T1 - T5). The rabbits in ...

  17. NAUCLEFOLININE: A NEW ALKALOID FROM THE ROOTS OF ...

    African Journals Online (AJOL)

    a

    NAUCLEFOLININE: A NEW ALKALOID FROM THE ROOTS OF. NAUCLEA LATIFOLIA. D. Ngnokam1*, J.F. Ayafor1, J.D. Connolly2 and J.M. Nuzillard3. 1Department of Chemistry, University of Dschang, Box 67 Dschang, Cameroon. 2Department of Organic Chemistry, University of Glasgow, Glasgow G12 8QQ, Scotland.

  18. Attainment of Electron Beam Suitable for Medium Energy Electron Cooling

    International Nuclear Information System (INIS)

    Seletskiy, Sergey M.; Rochester U.

    2005-01-01

    Electron cooling of charged particle beams is a well-established technique at electron energies of up to 300 keV. However, up to the present time the advance of electron cooling to the MeV-range energies has remained a purely theoretical possibility. The electron cooling project at Fermilab has recently demonstrated the first cooling of 8.9 GeV/c antiprotons in the Recycler ring, and therefore, has proved the validity of the idea of relativistic electron cooling. The Recycler Electron Cooler (REC) is the key component of the Tevatron Run II luminosity upgrade project. Its performance depends critically on the quality of electron beam. A stable electron beam of 4.3 MeV carrying 0.5 A of DC current is required. The beam suitable for the Recycler Electron Cooler must have an angular spread not exceeding 200 (micro)rad. The full-scale prototype of the REC was designed, built and tested at Fermilab in the Wideband laboratory to study the feasibility of attaining the high-quality electron beam. In this thesis I describe various aspects of development of the Fermilab electron cooling system, and the techniques used to obtain the electron beam suitable for the cooling process. In particular I emphasize those aspects of the work for which I was principally responsible. Chapter 1 is an introduction where I describe briefly the theory and the history of electron cooling, and derive the requirements to the quality of electron beam and requirements to the basic parameters of the Recycler Electron Cooler. Chapter 2 is devoted to the theoretical consideration of the motion of electrons in the cooling section, description of the cooling section and of the measurement of the magnetic fields. In Chapter 3 I consider different factors that increase the effective electron angle in the cooling section and suggest certain algorithms for the suppression of parasitic angles. Chapter 4 is devoted to the measurements of the energy of the electron beam. In the concluding Chapter 5 I review

  19. Double differential distributions of electron emission in ion-atom and electron-atom collisions using an electron spectrometer

    International Nuclear Information System (INIS)

    Misra, Deepankar; Thulasiram, K.V.; Fernandes, W.; Kelkar, Aditya H.; Kadhane, U.; Kumar, Ajay; Singh, Yeshpal; Gulyas, L.; Tribedi, Lokesh C.

    2009-01-01

    We study electron emission from atoms and molecules in collisions with fast electrons and heavy ions (C 6+ ). The soft collision electrons (SE), two center electron emission (TCEE), the binary encounter (BE) events and the KLL Auger lines along with the elastically scattered peaks (in electron collisions) are studied using a hemispherical electrostatic electron analyzer. The details of the measurements along with description of the spectrometer and data acquisition system are given. The angular distributions of the low energy (few eV) electrons in soft collisions and the binary encounter electrons at keV energies are compared with quantum mechanical models based on the first Born (B1) and the continuum distorted wave-Eikonal initial state approximation (CDW-EIS).

  20. VIRTUAL ELECTRONIC COMPONENTS OF THE ELECTRONIC EQUIPMENT

    Directory of Open Access Journals (Sweden)

    E. Lazarevich

    2013-01-01

    Full Text Available The article is present new idea of the creation, developments and improvements of the electronic equipment of complex systems by means of the virtual electronic components. The idea of the virtual electronic components is a presentation and perception of the creation and developments of the equipment on two forming: real – in the manner of standard marketed block of the intellectual property and image – in the manner of virtual component. The real component in most cases slows the development of the electronic equipment. The imaginary component is the «locomotive» of development of the electronic equipment. The Imaginary component contains the scientific has brushed against developer. The scientific has brushed against developer reveals of itself in the manner of virtual component on the modern level of the design rates of microelectronics.

  1. A new stage of nuclear electronics-particle electronics

    International Nuclear Information System (INIS)

    Xi Deming

    1987-01-01

    The rapid development of high energy physics experiments has pushed the nuclear electronics to a new stage, i.e. the particle electronics. In this paper the background, main features and recent trends of the particle electronics are expounded

  2. Electron transport effects in ion induced electron emission

    Energy Technology Data Exchange (ETDEWEB)

    Dubus, A. [Universite Libre de Bruxelles, Service de Metrologie Nucleaire (CP 165/84), 50 av. FD Roosevelt, B-1050 Brussels (Belgium)]. E-mail: adubus@ulb.ac.be; Pauly, N. [Universite Libre de Bruxelles, Service de Metrologie Nucleaire (CP 165/84), 50 av. FD Roosevelt, B-1050 Brussels (Belgium); Roesler, M. [Karl-Pokern-Str. 12, D-12587 Berlin (Germany)

    2007-03-15

    Ion induced electron emission (IIEE) is usually described as a three-step process, i.e. electron excitation by the incident projectile, electron transport (and multiplication) and electron escape through the potential barrier at the surface. In many cases, the first step of the process has been carefully described. The second step of the process, i.e. electron transport and multiplication, has often been treated in a very rough way, a simple decreasing exponential law being sometimes used. It is precisely the aim of the present work to show the importance of a correct description of electron transport and multiplication in a theoretical calculation of IIEE. A short overview of the electron transport models developed for IIEE is given in this work. The so-called 'Infinite medium slowing-down model' often used in recent works is evaluated by means of Monte Carlo simulations. In particular, the importance of considering correctly the semi-infinite character of the medium and the boundary condition at the vacuum-medium interface is discussed. Quantities like the electron escape depth are also briefly discussed. This evaluation has been performed in the particular case of protons (25keV

  3. Studying electron-PAG interactions using electron-induced fluorescence

    Science.gov (United States)

    Narasimhan, Amrit; Grzeskowiak, Steven; Ostrander, Jonathan; Schad, Jonathon; Rebeyev, Eliran; Neisser, Mark; Ocola, Leonidas E.; Denbeaux, Gregory; Brainard, Robert L.

    2016-03-01

    In extreme ultraviolet (EUV) lithography, 92 eV photons are used to expose photoresists. Typical EUV resists are organic-based and chemically amplified using photoacid generators (PAGs). Upon exposure, PAGs produce acids which catalyze reactions that result in changes in solubility. In EUV lithography, photo- and secondary electrons (energies of 10- 80 eV) play a large role in PAG acid-production. Several mechanisms for electron-PAG interactions (e.g. electron trapping, and hole-initiated chemistry) have been proposed. The aim of this study is to explore another mechanism - internal excitation - in which a bound PAG electron can be excited by receiving energy from another energetic electron, causing a reaction that produces acid. This paper explores the mechanism of internal excitation through the analogous process of electron-induced fluorescence, in which an electron loses energy by transferring that energy to a molecule and that molecule emits a photon rather than decomposing. We will show and quantify electron-induced fluorescence of several fluorophores in polymer films to mimic resist materials, and use this information to refine our proposed mechanism. Relationships between the molecular structure of fluorophores and fluorescent quantum yield may aid in the development of novel PAGs for EUV lithography.

  4. Electron-electron Thomas peak in fast transfer ionization

    International Nuclear Information System (INIS)

    Tolmanov, S. G.; McGuire, J. H.

    2000-01-01

    ''Thomas process'' is a name used for a family of singular two-step processes that can lead to electron transfer. The Thomas process of the ''second kind,'' occurring in reactions with both transfer and ionization, utilizes the e-e scattering in the second step, so this Thomas process requires the dynamics of the electron-electron interaction. We calculate numerically the second order element of an S matrix and corresponding cross sections for the transfer ionization process. We find that the position and shape of the Thomas peak depend on both electron-electron and the electron-nucleus interaction. Also the direct and exchange amplitudes are equal at the peak position. We test the peaking approximation used for transfer ionization. Our results can be compared to experimental results for p + +He→H+He 2+ +e - . (c) 2000 The American Physical Society

  5. Electron Tree

    DEFF Research Database (Denmark)

    Appelt, Ane L; Rønde, Heidi S

    2013-01-01

    The photo shows a close-up of a Lichtenberg figure – popularly called an “electron tree” – produced in a cylinder of polymethyl methacrylate (PMMA). Electron trees are created by irradiating a suitable insulating material, in this case PMMA, with an intense high energy electron beam. Upon discharge......, during dielectric breakdown in the material, the electrons generate branching chains of fractures on leaving the PMMA, producing the tree pattern seen. To be able to create electron trees with a clinical linear accelerator, one needs to access the primary electron beam used for photon treatments. We...... appropriated a linac that was being decommissioned in our department and dismantled the head to circumvent the target and ion chambers. This is one of 24 electron trees produced before we had to stop the fun and allow the rest of the accelerator to be disassembled....

  6. Electronic Raman response in electron-doped cuprate superconductors

    International Nuclear Information System (INIS)

    Geng Zhihao; Feng Shiping

    2012-01-01

    The electronic Raman response in the electron-doped cuprate superconductors is studied based on the t-t'-J model. It is shown that although the domelike shape of the doping dependent peak energy in the B 2g symmetry is a common feature for both electron-doped and hole-doped cuprate superconductors, there are pronounced deviations from a cubic response in the B 2g channel and a linear response in the B 2g channel for the electron-doped case in the low energy limit. It is also shown that these pronounced deviations are mainly caused by a nonmonotonic d-wave gap in the electron-doped cuprate superconductors.

  7. Spectroscopy of electron irradiated polymers in electron microscope

    International Nuclear Information System (INIS)

    Faraj, S.H.; Salih, S.M.

    1981-01-01

    The damage induced by energetic electrons in the course of irradiation of polymers in a transmission electron microscope was investigated spectroscopically. Damage on the molecular level has been detected at very low exposure doses. These effects have been induced by electron doses less than that received by the specimen when it is situated at its usual place of the specimen stage in the electron microscope by a factor of 1,000. (author)

  8. Electron spectroscopy in the fundamental process of electron-nucleus bremsstrahlung

    International Nuclear Information System (INIS)

    Hillenbrand, Pierre-Michel

    2013-07-01

    Within the scope of this thesis the fundamental process of electron-nucleus bremsstrahlung was studied in inverse kinematics at the Experimental Storage Ring ESR at GSI. For the system U 88+ + N 2 at 90 MeV/u it was shown, that by using inverse kinematics coincidence measurements between the scattered electron and the emitted photon can be performed for the case, in which the incoming electron transfers almost all of its kinetic energy onto the emitted photon. The sensitivity to the fundamental process could be achieved by measuring triple differential cross sections as a function of the emission angle of the photon and the scattered electron as well as the energy of the scattered electron. The optics of the magnetic electron spectrometer used were thoroughly revised and optimized to the experimental requirements. Analyzing different coincidences in this collision system, it was possible to determine the contributions to the electron distribution arising from radiative electron capture to the projectile continuum, nonradiative electron capture to the projectile continuum, and electron loss to the projectile continuum. The experimental results of each of these processes were compared to theoretical calculations. The electron spectra for the radiative and the nonradiative electron capture to continuum clearly reproduce the opposite asymmetry predicted by theory. Furthermore electron spectra for collisions of U 28+ with different gases were measured.

  9. Change in Caco-2 cells following treatment with various lavender essential oils.

    Science.gov (United States)

    Donadu, M G; Usai, D; Mazzarello, V; Molicotti, P; Cannas, S; Bellardi, M G; Zanetti, S

    2017-09-01

    Lavender is an aromatic evergreen shrub diffused in the Mediterranean basin appreciated since antiquity. The genus Lavandula is part of Lamiaceae family and includes more than 20 species, among which true lavender (L. vera D.C. or L. angustifolia Miller.) and spike lavender (L. latifolia Medikus); there are also numerous hybrids known as lavandins (L. hybrida Rev.). L. vera, spike lavender and several hybrids are the most intensely used breeding species for the production of essential oils. Lavender and lavandin essential oils have been applied in food, pharmaceutical and other agro industries as biological products. In their chemical composition, terpenes linalool and linalyl acetate along with terpenoids such as 1,8-cineole are mostly responsible for biological and therapeutic activities. This study evaluates cytotoxic activity of essential oils derived from four lavender species on human epithelial colorectal adenocarcinoma cells. Analysis of pre- and post-treatment cell morphology has been performed using scanning electron microscope.

  10. `Twisted' electrons

    Science.gov (United States)

    Larocque, Hugo; Kaminer, Ido; Grillo, Vincenzo; Leuchs, Gerd; Padgett, Miles J.; Boyd, Robert W.; Segev, Mordechai; Karimi, Ebrahim

    2018-04-01

    Electrons have played a significant role in the development of many fields of physics during the last century. The interest surrounding them mostly involved their wave-like features prescribed by the quantum theory. In particular, these features correctly predict the behaviour of electrons in various physical systems including atoms, molecules, solid-state materials, and even in free space. Ten years ago, new breakthroughs were made, arising from the new ability to bestow orbital angular momentum (OAM) to the wave function of electrons. This quantity, in conjunction with the electron's charge, results in an additional magnetic property. Owing to these features, OAM-carrying, or twisted, electrons can effectively interact with magnetic fields in unprecedented ways and have motivated materials scientists to find new methods for generating twisted electrons and measuring their OAM content. Here, we provide an overview of such techniques along with an introduction to the exciting dynamics of twisted electrons.

  11. The electron

    International Nuclear Information System (INIS)

    Hestenes, David; Weingartshofer, Antonio

    1991-01-01

    The stupendous successes of the Dirac equation and quantum electro-dynamics have established the electron as the best understood of the fundamental constituents of matter. Nevertheless, physicists agree that the electron still has secrets to reveal. Moreover, powerful new theoretical and experimental tools for probing those secrets have been sharpened during the last decade. This workshop was organized to bring theorists and experimentalists together to discuss their common goal of knowing the electron. Present state and future prospects for progress toward that goal are here described. The theoretical papers encompass a wide range of views on the electron. Several argue that the 'Zitter-bewegung' is more than a mathematical peculiarity of the Dirac equation, that it may well be a real physical phenomenon and worthy of serious study, theoretically and experimentally. Besides generating the electron spin and magnetic moment, the 'Zitterbewegung' may be a vital clue to electron structure and self-interaction. Some of the papers employ a radical new formulation of the Dirac theory which reveals a hidden geo-metric structure in the theory that supports a 'Zitterbewegung' inter-pretation. For the last half century the properties of electrons have been probed primarily by scattering experiments at ever higher energies. Recently, however, two powerful new experimental techniques have emerged capable of giving alternative experimental views of the electron. First, techniques for confining single electrons for long term study have led to the most accurate measurements of the electron magnetic moment. Second, the interaction of high intensity laser fields with atoms and electrons have revealed striking new phenomena such as multiphoton ionization. refs.; figs.; tabs

  12. Basic electronics

    CERN Document Server

    Holbrook, Harold D

    1971-01-01

    Basic Electronics is an elementary text designed for basic instruction in electricity and electronics. It gives emphasis on electronic emission and the vacuum tube and shows transistor circuits in parallel with electron tube circuits. This book also demonstrates how the transistor merely replaces the tube, with proper change of circuit constants as required. Many problems are presented at the end of each chapter. This book is comprised of 17 chapters and opens with an overview of electron theory, followed by a discussion on resistance, inductance, and capacitance, along with their effects on t

  13. Electron-electron scattering and mobilities in semiconductors and quantum wells

    International Nuclear Information System (INIS)

    Lyo, S.K.

    1986-01-01

    The effect of electron-electron scattering on the mobility in semiconductors and semiconductor quantum wells is examined. A general exact formula is derived for the mobility, when the electron-electron collision rate is much faster than other scattering rates such as those by ionized impurities and phonons. In this limit, the transport relaxation rate is independent of the carrier's energy and contributions to the inverse mobility from individual scattering mechanism add up. The mobility becomes significantly reduced from its value in the absence of electron-electron scattering. When the collision rates are not necessarily dominated by electron-electron scattering, the mobility is calculated by the Kohler-Sondheimer variational method in the presence of ionized-impurity scattering and acoustic-phonon scattering in a nondegenerate two-dimensional quantum well

  14. Analysis of Tospovirus NSs Proteins in Suppression of Systemic Silencing

    OpenAIRE

    Hedil, Marcio; Sterken, Mark G.; de Ronde, Dryas; Lohuis, Dick; Kormelink, Richard

    2015-01-01

    RNA silencing is a sequence-specific gene regulation mechanism that in plants also acts antiviral. In order to counteract antiviral RNA silencing, viruses have evolved RNA silencing suppressors (RSS). In the case of tospoviruses, the non-structural NSs protein has been identified as the RSS. Although the tomato spotted wilt virus (TSWV) tospovirus NSs protein has been shown to exhibit affinity to long and small dsRNA molecules, its ability to suppress the non-cell autonomous part of RNA silen...

  15. Modified Monte Carlo method for study of electron transport in degenerate electron gas in the presence of electron-electron interactions, application to graphene

    Science.gov (United States)

    Borowik, Piotr; Thobel, Jean-Luc; Adamowicz, Leszek

    2017-07-01

    Standard computational methods used to take account of the Pauli Exclusion Principle into Monte Carlo (MC) simulations of electron transport in semiconductors may give unphysical results in low field regime, where obtained electron distribution function takes values exceeding unity. Modified algorithms were already proposed and allow to correctly account for electron scattering on phonons or impurities. Present paper extends this approach and proposes improved simulation scheme allowing including Pauli exclusion principle for electron-electron (e-e) scattering into MC simulations. Simulations with significantly reduced computational cost recreate correct values of the electron distribution function. Proposed algorithm is applied to study transport properties of degenerate electrons in graphene with e-e interactions. This required adapting the treatment of e-e scattering in the case of linear band dispersion relation. Hence, this part of the simulation algorithm is described in details.

  16. Attainment of Electron Beam Suitable for Medium Energy Electron Cooling

    Energy Technology Data Exchange (ETDEWEB)

    Seletskiy, Sergei M. [Univ. of Rochester, NY (United States)

    2005-01-01

    Electron cooling of charged particle beams is a well-established technique at electron energies of up to 300 keV. However, up to the present time the advance of electron cooling to the MeV-range energies has remained a purely theoretical possibility. The electron cooling project at Fermilab has recently demonstrated the ¯rst cooling of 8.9 GeV/c antiprotons in the Recycler ring, and therefore, has proved the validity of the idea of relativistic electron cool- ing. The Recycler Electron Cooler (REC) is the key component of the Teva- tron Run II luminosity upgrade project. Its performance depends critically on the quality of electron beam. A stable electron beam of 4.3 MeV car- rying 0.5 A of DC current is required. The beam suitable for the Recycler Electron Cooler must have an angular spread not exceeding 200 ¹rad. The full-scale prototype of the REC was designed, built and tested at Fermilab in the Wideband laboratory to study the feasibility of attaining the high-quality electron beam. In this thesis I describe various aspects of development of the Fermilab electron cooling system, and the techniques used to obtain the electron beam suitable for the cooling process. In particular I emphasize those aspects of the work for which I was principally responsible.

  17. Potential change in lodgepole pine site index and distribution under climatic change in Alberta.

    Science.gov (United States)

    Robert A. Monserud; Yuqing Yang; Shongming Huang; Nadja Tchebakova

    2008-01-01

    We estimated the impact of global climate change on lodgepole pine (Pinus contorta Dougl. ex. Loud. var. latifolia Engelm.) site productivity in Alberta based on the Alberta Climate Model and the A2 SRES climate change scenario projections from three global circulation models (CGCM2, HADCM3, and ECHAM4). Considerable warming is...

  18. Realistic Bomber Training Initiative. Environmental Impact Statement. Volume 1

    Science.gov (United States)

    2000-01-01

    arizonica Bitterweed Hymenoxys odorata Black grama Bouteloua eriopoda Broadleaf milkweed Ascelpias latifolia Broomweed Amphiachyris spp. and...Larrea tridentata Douglas fir Pseudotsuga menziesii Fragrant ash Fraxinus cuspidata Galleta grass Hilaria jamesii Gambel (=shin) oak Quercus gambelii...Guajillo Acacia berlandieri Juniper Juniperus spp. Little bluestem Schizachyrium scoparium Live oak Quercus turbinella Mesquite Prosopis spp. Mexican

  19. Severity of a mountain pine beetle outbreak across a range of stand conditions in Fraser Experimental Forest, Colorado, United States

    Science.gov (United States)

    Anthony G. Vorster; Paul H. Evangelista; Thomas J. Stohlgren; Sunil Kumar; Charles C. Rhoades; Robert M. Hubbard; Antony S. Cheng; Kelly Elder

    2017-01-01

    The recent mountain pine beetle (Dendroctonus ponderosae Hopkins) outbreaks had unprecedented effects on lodgepole pine (Pinus contorta var. latifolia) in western North America. We used data from 165 forest inventory plots to analyze stand conditions that regulate lodgepole pine mortality across a wide range of stand structure and species composition at the Fraser...

  20. Modeling the effects of fire and climate change on carbon and nitrogen storage in lodgepole pine (Pinus contorta) stands

    Science.gov (United States)

    E. A. H. Smithwick; M. G. Ryan; D. M. Kashian; W. H. Romme; D. B. Tinker; M. G. Turner

    2009-01-01

    The interaction between disturbance and climate change and resultant effects on ecosystem carbon (C) and nitrogen (N) fluxes are poorly understood. Here, we model (using CENTURY version 4.5) how climate change may affect C and N fluxes among mature and regenerating lodgepole pine (Pinus contorta var. latifolia Engelm. ex S.Wats.)...

  1. Effects of salvage logging on fire risks after bark beetle outbreaks in Colorado lodgepole pine forests

    Science.gov (United States)

    Bryon J. Collins; Chuck C. Rhoades; Michael A. Battaglia; Robert M. Hubbard

    2012-01-01

    Most mature lodgepole pine (Pinus contorta var. latifolia Engelm. ex Wats.) forests in the central and southern Rocky Mountains originated after stand-replacing wildfires or logging (Brown 1975, Lotan and Perry 1983, Romme 1982). In recent years, mountain pine beetle (Dendroctonus ponderosae Hopkins) outbreaks have created a widespread, synchronous disturbance (i.e.,...

  2. Asymbiotic seed germination and in vitro propagation of ...

    African Journals Online (AJOL)

    Joe Krawczyszyn

    2015-10-13

    Oct 13, 2015 ... Christenson. Plant Growth Regul. 65:381-387. Knudson L (1946). A new nutrient solution for the germination of orchid seed. Am. Orchid Soc. Bull. 14:214-217. Lloyd G, MCCown B (1980). Commercially-feasible micropropagation of mountain laurel, Kalmia latifolia, by use of shoot-tip culture. Int. Plant. Prop.

  3. Microfluidic electronics.

    Science.gov (United States)

    Cheng, Shi; Wu, Zhigang

    2012-08-21

    Microfluidics, a field that has been well-established for several decades, has seen extensive applications in the areas of biology, chemistry, and medicine. However, it might be very hard to imagine how such soft microfluidic devices would be used in other areas, such as electronics, in which stiff, solid metals, insulators, and semiconductors have previously dominated. Very recently, things have radically changed. Taking advantage of native properties of microfluidics, advances in microfluidics-based electronics have shown great potential in numerous new appealing applications, e.g. bio-inspired devices, body-worn healthcare and medical sensing systems, and ergonomic units, in which conventional rigid, bulky electronics are facing insurmountable obstacles to fulfil the demand on comfortable user experience. Not only would the birth of microfluidic electronics contribute to both the microfluidics and electronics fields, but it may also shape the future of our daily life. Nevertheless, microfluidic electronics are still at a very early stage, and significant efforts in research and development are needed to advance this emerging field. The intention of this article is to review recent research outcomes in the field of microfluidic electronics, and address current technical challenges and issues. The outlook of future development in microfluidic electronic devices and systems, as well as new fabrication techniques, is also discussed. Moreover, the authors would like to inspire both the microfluidics and electronics communities to further exploit this newly-established field.

  4. Electron-electron collision effects on the bremsstrahlung emission in Lorentzian plasmas

    International Nuclear Information System (INIS)

    Jung, Young-Dae; Kato, Daiji

    2009-01-01

    Electron-electron collision effects on the electron-ion bremsstrahlung process are investigated in Lorentzian plasmas. The effective electron-ion interaction potential is obtained by including the far-field terms caused by electron-electron collisions with an effective Debye length in Lorentzian plasmas. The bremsstrahlung radiation cross section is obtained as a function of the electron energy, photon energy, collision frequency, spectral index and Debye length using the Born approximation for the initial and final states of the projectile electron. It is shown that the non-Maxwellian character suppresses the bremsstrahlung radiation cross section. It is also shown that the electron-electron collision effect enhances the bremsstrahlung emission spectrum. In addition, the bremsstrahlung radiation cross section decreases with an increase in the plasma temperature.

  5. Electron-photon and electron-electron interactions in the presence of strong electromagnetic fields

    International Nuclear Information System (INIS)

    Surzhykov, A.; Fritzsche, S.; Stoehlker, Th.

    2010-01-01

    During the last decade, photon emission from highly-charged, heavy ions has been in the focus of intense studies at the GSI accelerator and storage ring facility in Darmstadt. These studies have revealed unique information about the electron-electron and electron-photon interactions in the presence of extremely strong nuclear fields. Apart from the radiative electron capture processes, characteristic photon emission following collisional excitation of projectile ions has also attracted much interest. In this contribution, we summarize the recent theoretical studies on the production of excited ionic states and their subsequent radiative decay. We will pay special attention to the angular and polarization properties of Kα emission from helium-like ions produced by means of dielectronic recombination. The results obtained for this (resonant) capture process will be compared with the theoretical predictions for the characteristic X-rays following Coulomb excitation and radiative recombination of few-electron, heavy ions. Work is supported by Helmholtz Association and GSl under the project VH-NG--421. (author)

  6. Sticker electronics

    KAUST Repository

    Hussain, Muhammad Mustafa

    2017-09-08

    Electronic stickers may be manufactured on flexible substrates (110, 120, 130) as layers and packaged together. The package may then have an adhesive applied to one side to provide capability for sticking the electronic devices to surfaces. The stickers can be wrappable, placed on surfaces, glued on walls or mirrors or wood or stone, and have electronics (112, 122, 132) which may or may not be ultrathin. Packaging for the electronic sticker can use polymer on cellulose manufacturing and/or three dimensional (3-D) printing. The electronic stickers may provide lighting capability, sensing capability, and/or recharging capabilities.

  7. Electronic Commerce

    Directory of Open Access Journals (Sweden)

    Slavko Đerić

    2016-12-01

    Full Text Available Electronic commerce can be defined in different ways. Any definition helps to understand and explain that concept as better as possible.. Electronic commerce is a set of procedures and technologies that automate the tasks of financial transactions using electronic means. Also, according to some authors, electronic commerce is defined as a new concept, which is being developed and which includes process of buying and selling or exchanging products, services or information via computer networks, including the Internet. Electronic commerce is not limited just to buying and selling, but it also includes all pre-sales and after-sales ongoing activities along the supply chain. Introducing electronic commerce, using the Internet and Web services in business, realizes the way to a completely new type of economy - internet economy.

  8. Observation of the two-electron cusp in atomic collisions. Evidence for strong electron-electron correlation

    International Nuclear Information System (INIS)

    Sarkadi, L.; Orban, A.

    2007-01-01

    Complete text of publication follows. In this report we present experimental data for a process when two electrons with velocity vectors equal to that of the projectile are emitted from collisions. By observing the two electron cusp the study of the threshold phenomenon for two-electron break-up is possible. It is a particularly interesting question whether the outgoing charged projectile can attract the two repulsing electrons so strongly that the two-electron cusp is formed. If it is so, a further question arises: Are the two electrons correlated in the final state as it is predicted by the Wannier theory? The experiments have been done at the 1 MeV VdG accelerator of ATOMKI using our TOF spectrometer. The first measurements clearly showed the formation of the two-electron cusp and signature of the electron correlation in 200 keV He 0 +He collisions. These promising results motivated us to carry out the experiment at 100 keV beam energy where the coincidence count rate is still reasonable but the energy resolution is better. For an acceptable data acquisition time we improved our data acquisition and data processing system for triple coincidence measurements. In Fig. 1a we present our measured relative fourfold differential cross section (FDCS) that shows strong electron correlation. For a comparison, in Fig. 1b we displayed the contour plot for uncorrelated electron pair emission. These latter data were synthesized artificially, generating the energies of the electron pairs from two independent double coincidence experiments. In both figures the distributions are characterized by two ridges. In Fig. 1b the ridges are perpendicular straight lines (E 1 = E 2 .13.6 eV). As a result of the correlation, the ridges in Fig. 1a are distorted in such a way that they have a joint straight-line section following the line E 1 + E 2 = 27.2 eV. This means that the electron pairs in the vicinity of the cusp maximum are emitted with a center of- mass velocity equal to that of

  9. Electronics and Information

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Previously founded as CCPITMachinery and Electronics Sub-council and CCOIC Machinery and Electronics Chamber of Corn-merce in June, 1988, CCPIT Electronics Sub-Council and CCOIC Electronics Chamber of Commerce were established in May, 1993, and then renamed as CCPIT Electronics and Information Industry Sub-council and CCOIC Electronics and Infor-mation Industry Chamber of Commerce (CCPITECC) in September 1999.

  10. Spontaneous and stimulated emission induced by an electron, electron bunch, and electron beam in a plasma

    International Nuclear Information System (INIS)

    Kuzelev, M V; Rukhadze, A A

    2008-01-01

    Two fundamental mechanisms - the Cherenkov effect and anomalous Doppler effect - underlying the emission by an electron during its superluminal motion in medium are considered. Cherenkov emission induced by a single electron and a small electron bunch is spontaneous. In the course of spontaneous Cherenkov emission, the translational motion of an electron is slowed down and the radiation energy grows linearly with time. As the number of radiating electrons increases, Cherenkov emission becomes stimulated. Stimulated Cherenkov emission represents a resonance beam instability. This emission process is accompanied by longitudinal electron bunching in the beam or by the breaking of an electron bunch into smaller bunches, in which case the radiation energy grows exponentially with time. In terms of the longitudinal size L e of the electron bunch there is a transition region λ e 0 -1 between the spontaneous and stimulated Cherenkov effects, where λ is the average radiation wavelength, and δ 0 is the dimensionless (in units of the radiation frequency) growth rate of the Cherenkov beam instability. The range to the left of this region is dominated by spontaneous emission, whereas the range to the right of this region is dominated by stimulated emission. In contrast to the Vavilov-Cherenkov effect, the anomalous Doppler effect should always (even for a single electron) be considered as stimulated, because it can only be explained by accounting for the reverse action of the radiation field on the moving electron. During stimulated emission in conditions where anomalous Doppler effect shows itself, an electron is slowed down and spins up; in this case, the radiation energy grows exponentially with time. (reviews of topical problems)

  11. High perveance electron gun for the electron cooling system

    International Nuclear Information System (INIS)

    Korotaev, Yu.; Meshkov, I.; Petrov, A.; Sidorin, A.; Smirnov, A.; Syresin, E.; Titkova, I.

    2000-01-01

    The cooling time in the electron cooling system is inversely proportional to the beam current. To obtain high current of the electron beam the control electrode of the gun is provided with a positive potential and an electrostatic trap for secondary electrons appears inside the electron gun. This leads to a decrease in the gun perveance. To avoid this problem, the adiabatic high perveance electron gun with the clearing control electrode is designed in JINR (J. Bosser, Y. Korotaev, I. Meshkov, E. Syresin et al., Nucl. Instr. and Meth. A 391 (1996) 103. Yu. Korotaev, I. Meshkov, A. Sidorin, A. Smirnov, E. Syresin, The generation of electron beams with perveance of 3-6 μA/V 3/2 , Proceedings of SCHEF'99). The clearing control electrode has a transverse electric field, which clears secondary electrons. Computer simulations of the potential map were made with RELAX3D computer code (C.J. Kost, F.W. Jones, RELAX3D User's Guide and References Manual)

  12. High perveance electron gun for the electron cooling system

    CERN Document Server

    Korotaev, Yu V; Petrov, A; Sidorin, A; Smirnov, A; Syresin, E M; Titkova, I

    2000-01-01

    The cooling time in the electron cooling system is inversely proportional to the beam current. To obtain high current of the electron beam the control electrode of the gun is provided with a positive potential and an electrostatic trap for secondary electrons appears inside the electron gun. This leads to a decrease in the gun perveance. To avoid this problem, the adiabatic high perveance electron gun with the clearing control electrode is designed in JINR (J. Bosser, Y. Korotaev, I. Meshkov, E. Syresin et al., Nucl. Instr. and Meth. A 391 (1996) 103. Yu. Korotaev, I. Meshkov, A. Sidorin, A. Smirnov, E. Syresin, The generation of electron beams with perveance of 3-6 mu A/V sup 3 sup / sup 2 , Proceedings of SCHEF'99). The clearing control electrode has a transverse electric field, which clears secondary electrons. Computer simulations of the potential map were made with RELAX3D computer code (C.J. Kost, F.W. Jones, RELAX3D User's Guide and References Manual).

  13. Study of single-electron excitations by electron microscopy

    International Nuclear Information System (INIS)

    Craven, A.J.; Gibson, J.M.; Howie, A.; Spalding, D.R.

    1978-01-01

    The inelastic scattering of fast electrons by the excitation of L-shell electrons at a stacking fault in silicon has been studied with a scanning transmission electron microscope. It was found that the bright-field stacking fault contrast is preserved in the filtered L-shell-loss signal at 100 eV. This result is discussed in terms of the delocalization of the excitation mechanism. It is concluded that localization effects will typically become significant only for energy transfers greater than 1 keV from a fast electron of energy 80 keV. (author)

  14. Syringe injectable electronics

    Science.gov (United States)

    Hong, Guosong; Zhou, Tao; Jin, Lihua; Duvvuri, Madhavi; Jiang, Zhe; Kruskal, Peter; Xie, Chong; Suo, Zhigang; Fang, Ying; Lieber, Charles M.

    2015-01-01

    Seamless and minimally-invasive three-dimensional (3D) interpenetration of electronics within artificial or natural structures could allow for continuous monitoring and manipulation of their properties. Flexible electronics provide a means for conforming electronics to non-planar surfaces, yet targeted delivery of flexible electronics to internal regions remains difficult. Here, we overcome this challenge by demonstrating syringe injection and subsequent unfolding of submicrometer-thick, centimeter-scale macroporous mesh electronics through needles with a diameter as small as 100 micrometers. Our results show that electronic components can be injected into man-made and biological cavities, as well as dense gels and tissue, with > 90% device yield. We demonstrate several applications of syringe injectable electronics as a general approach for interpenetrating flexible electronics with 3D structures, including (i) monitoring of internal mechanical strains in polymer cavities, (ii) tight integration and low chronic immunoreactivity with several distinct regions of the brain, and (iii) in vivo multiplexed neural recording. Moreover, syringe injection enables delivery of flexible electronics through a rigid shell, delivery of large volume flexible electronics that can fill internal cavities and co-injection of electronics with other materials into host structures, opening up unique applications for flexible electronics. PMID:26053995

  15. Electronic Nose and Electronic Tongue

    Science.gov (United States)

    Bhattacharyya, Nabarun; Bandhopadhyay, Rajib

    Human beings have five senses, namely, vision, hearing, touch, smell and taste. The sensors for vision, hearing and touch have been developed for several years. The need for sensors capable of mimicking the senses of smell and taste have been felt only recently in food industry, environmental monitoring and several industrial applications. In the ever-widening horizon of frontier research in the field of electronics and advanced computing, emergence of electronic nose (E-Nose) and electronic tongue (E-Tongue) have been drawing attention of scientists and technologists for more than a decade. By intelligent integration of multitudes of technologies like chemometrics, microelectronics and advanced soft computing, human olfaction has been successfully mimicked by such new techniques called machine olfaction (Pearce et al. 2002). But the very essence of such research and development efforts has centered on development of customized electronic nose and electronic tongue solutions specific to individual applications. In fact, research trends as of date clearly points to the fact that a machine olfaction system as versatile, universal and broadband as human nose and human tongue may not be feasible in the decades to come. But application specific solutions may definitely be demonstrated and commercialized by modulation in sensor design and fine-tuning the soft computing solutions. This chapter deals with theory, developments of E-Nose and E-Tongue technology and their applications. Also a succinct account of future trends of R&D efforts in this field with an objective of establishing co-relation between machine olfaction and human perception has been included.

  16. A theory of electron baths: One-electron system dynamics

    International Nuclear Information System (INIS)

    McDowell, H.K.

    1992-01-01

    The second-quantized, many-electron, atomic, and molecular Hamiltonian is partitioned both by the identity or labeling of the spin orbitals and by the dynamics of the spin orbitals into a system coupled to a bath. The electron bath is treated by a molecular time scale generalized Langevin equation approach designed to include one-electron dynamics in the system dynamics. The bath is formulated as an equivalent chain of spin orbitals through the introduction of equivalent-chain annihilation and creation operators. Both the dynamics and the quantum grand canonical statistical properties of the electron bath are examined. Two versions for the statistical properties of the bath are pursued. Using a weak bath assumption, a bath statistical average is defined which allows one to achieve a reduced dynamics description of the electron system which is coupled to the electron bath. In a strong bath assumption effective Hamiltonians are obtained which reproduce the dynamics of the bath and which lead to the same results as found in the weak bath assumption. The effective (but exact) Hamiltonian is found to be a one-electron Hamiltonian. A reduced dynamics equation of motion for the system population matrix is derived and found to agree with a previous version. This equation of motion is useful for studying electron transfer in the system when coupled to an electron bath

  17. Treatment of foods with 'soft-electrons' (low-energy electrons)

    International Nuclear Information System (INIS)

    Hayashi, Toru; Todoriki, Setsuko

    2003-01-01

    Electrons with energies of 300 keV or lower were defined as soft-electrons'. Soft-electrons can eradicate microorganisms residing on the surface of grains, pulses, spices, dehydrated vegetables, tea leaves and seeds, and reduce their microbial loads to levels lower than 10 CFU/g with little quality deterioration. Soft-electrons can inactivate insect pests infesting grains and pulses and inhibit sprouting of potatoes. (author)

  18. Compact femtosecond electron diffractometer with 100 keV electron bunches approaching the single-electron pulse duration limit

    International Nuclear Information System (INIS)

    Waldecker, Lutz; Bertoni, Roman; Ernstorfer, Ralph

    2015-01-01

    We present the design and implementation of a highly compact femtosecond electron diffractometer working at electron energies up to 100 keV. We use a multi-body particle tracing code to simulate electron bunch propagation through the setup and to calculate pulse durations at the sample position. Our simulations show that electron bunches containing few thousands of electrons per bunch are only weakly broadened by space-charge effects and their pulse duration is thus close to the one of a single-electron wavepacket. With our compact setup, we can create electron bunches containing up to 5000 electrons with a pulse duration below 100 fs on the sample. We use the diffractometer to track the energy transfer from photoexcited electrons to the lattice in a thin film of titanium. This process takes place on the timescale of few-hundred femtoseconds and a fully equilibrated state is reached within 1 ps

  19. Electron backscattering for process control in electron beam welding

    International Nuclear Information System (INIS)

    Ardenne, T. von; Panzer, S.

    1983-01-01

    A number of solutions to the automation of electron beam welding is presented. On the basis of electron backscattering a complex system of process control has been developed. It allows an enlarged imaging of the material's surface, improved adjustment of the beam focusing and definite focus positioning. Furthermore, both manual and automated positioning of the electron beam before and during the welding process has become possible. Monitoring of the welding process for meeting standard welding requirements can be achieved with the aid of a control quantity derived from the results of electronic evaluation of the high-frequency electron backscattering

  20. Electron transfer reactions

    CERN Document Server

    Cannon, R D

    2013-01-01

    Electron Transfer Reactions deals with the mechanisms of electron transfer reactions between metal ions in solution, as well as the electron exchange between atoms or molecules in either the gaseous or solid state. The book is divided into three parts. Part 1 covers the electron transfer between atoms and molecules in the gas state. Part 2 tackles the reaction paths of oxidation states and binuclear intermediates, as well as the mechanisms of electron transfer. Part 3 discusses the theories and models of the electron transfer process; theories and experiments involving bridged electron transfe

  1. Understand electronics

    CERN Document Server

    Bishop, Owen

    2013-01-01

    Understand Electronics provides a readable introduction to the exciting world of electronics for the student or enthusiast with little previous knowledge. The subject is treated with the minimum of mathematics and the book is extensively illustrated.This is an essential guide for the newcomer to electronics, and replaces the author's best-selling Beginner's Guide to Electronics.The step-by-step approach makes this book ideal for introductory courses such as the Intermediate GNVQ.

  2. Electronic Commerce

    OpenAIRE

    Slavko Đerić

    2016-01-01

    Electronic commerce can be defined in different ways. Any definition helps to understand and explain that concept as better as possible.. Electronic commerce is a set of procedures and technologies that automate the tasks of financial transactions using electronic means. Also, according to some authors, electronic commerce is defined as a new concept, which is being developed and which includes process of buying and selling or exchanging products, services or information via computer networks...

  3. Photon and electron collimator effects on electron output and abutting segments in energy modulated electron therapy

    International Nuclear Information System (INIS)

    Olofsson, Lennart; Karlsson, Magnus G.; Karlsson, Mikael

    2005-01-01

    In energy modulated electron therapy a large fraction of the segments will be arranged as abutting segments where inhomogeneities in segment matching regions must be kept as small as possible. Furthermore, the output variation between different segments should be minimized and must in all cases be well predicted. For electron therapy with add-on collimators, both the electron MLC (eMLC) and the photon MLC (xMLC) contribute to these effects when an xMLC tracking technique is utilized to reduce the x-ray induced leakage. Two add-on electron collimator geometries have been analyzed using Monte Carlo simulations: One isocentric eMLC geometry with an isocentric clearance of 35 cm and air or helium in the treatment head, and one conventional proximity geometry with a clearance of 5 cm and air in the treatment head. The electron fluence output for 22.5 MeV electrons is not significantly affected by the xMLC if the shielding margins are larger than 2-3 cm. For small field sizes and 9.6 MeV electrons, the isocentric design with helium in the treatment head or shielding margins larger than 3 cm is needed to avoid a reduced electron output. Dose inhomogeneity in the matching region of electron segments is, in general, small when collimator positions are adjusted to account for divergence in the field. The effect of xMLC tracking on the electron output can be made negligible while still obtaining a substantially reduced x-ray leakage contribution. Collimator scattering effects do not interfere significantly when abutting beam techniques are properly applied

  4. Equation satisfied by electron-electron mutual Coulomb repulsion energy density functional

    OpenAIRE

    Joubert, Daniel P.

    2011-01-01

    The electron-electron mutual Coulomb repulsion energy density functional satisfies an equation that links functionals and functional derivatives at N-electron and (N-1)-electron densities for densities determined from the same adiabatic scaled external potential for the N-electron system.

  5. Electronic Publishing.

    Science.gov (United States)

    Lancaster, F. W.

    1989-01-01

    Describes various stages involved in the applications of electronic media to the publishing industry. Highlights include computer typesetting, or photocomposition; machine-readable databases; the distribution of publications in electronic form; computer conferencing and electronic mail; collaborative authorship; hypertext; hypermedia publications;…

  6. Syringe-injectable electronics.

    Science.gov (United States)

    Liu, Jia; Fu, Tian-Ming; Cheng, Zengguang; Hong, Guosong; Zhou, Tao; Jin, Lihua; Duvvuri, Madhavi; Jiang, Zhe; Kruskal, Peter; Xie, Chong; Suo, Zhigang; Fang, Ying; Lieber, Charles M

    2015-07-01

    Seamless and minimally invasive three-dimensional interpenetration of electronics within artificial or natural structures could allow for continuous monitoring and manipulation of their properties. Flexible electronics provide a means for conforming electronics to non-planar surfaces, yet targeted delivery of flexible electronics to internal regions remains difficult. Here, we overcome this challenge by demonstrating the syringe injection (and subsequent unfolding) of sub-micrometre-thick, centimetre-scale macroporous mesh electronics through needles with a diameter as small as 100 μm. Our results show that electronic components can be injected into man-made and biological cavities, as well as dense gels and tissue, with >90% device yield. We demonstrate several applications of syringe-injectable electronics as a general approach for interpenetrating flexible electronics with three-dimensional structures, including (1) monitoring internal mechanical strains in polymer cavities, (2) tight integration and low chronic immunoreactivity with several distinct regions of the brain, and (3) in vivo multiplexed neural recording. Moreover, syringe injection enables the delivery of flexible electronics through a rigid shell, the delivery of large-volume flexible electronics that can fill internal cavities, and co-injection of electronics with other materials into host structures, opening up unique applications for flexible electronics.

  7. Electronic excitation of Na atom by electron impact

    International Nuclear Information System (INIS)

    Bielschowsky, C.E.; Souza, G.G.B. de; Lucas, C.A.; Nogueira, J.C.

    1988-01-01

    Electronic excitation of the 3s-3p transition in the Na atom was studied by intermediate energy electron impact spectroscopy. Differential Cross Sections (DCS) and Generalized Oscillator Strenghts (GOS) were determined experimentally for 1 KeV electrons. Theoretical results within the First Born Approximation as well as Glauber theory, were also performed. (A.C.A.S.) [pt

  8. Highly efficient electron gun with a single-atom electron source

    International Nuclear Information System (INIS)

    Ishikawa, Tsuyoshi; Urata, Tomohiro; Cho, Boklae; Rokuta, Eiji; Oshima, Chuhei; Terui, Yoshinori; Saito, Hidekazu; Yonezawa, Akira; Tsong, Tien T.

    2007-01-01

    The authors have demonstrated highly collimated electron-beam emission from a practical electron gun with a single-atom electron source; ∼80% of the total emission current entered the electron optics. This ratio was two or three orders of magnitude higher than those of the conventional electron sources such as a cold field emission gun and a Zr/O/W Schottky gun. At the pressure of less than 1x10 -9 Pa, the authors observed stable emission of 20 nA, which generates the specimen current of 5 pA required for scanning electron microscopes

  9. Electron-electron interaction in p-SiGe/Ge quantum wells

    International Nuclear Information System (INIS)

    Roessner, Benjamin; Kaenel, Hans von; Chrastina, Daniel; Isella, Giovanni; Batlogg, Bertram

    2005-01-01

    The temperature dependent magnetoresistance of high mobility p-SiGe/Ge quantum wells is studied with hole densities ranging from 1.7 to 5.9 x 10 11 cm -2 . At magnetic fields below the onset of quantum oscillations that reflect the high mobility values (up to 75000 cm 2 /Vs), we observe the clear signatures of electron-electron interaction. We compare our experiment with the theory of electron-electron interaction including the Zeeman band splitting. The observed magnetoresistance is well explained as a superposition of band structure induced positive magnetoresistance and the negative magntoresistance due to the electron-electron interaction effect

  10. Contrasting impacts of continuous moderate drought and episodic severe droughts on the aboveground-biomass increment and litterfall of three coexisting Mediterranean woody species.

    Science.gov (United States)

    Liu, Daijun; Ogaya, Romà; Barbeta, Adrià; Yang, Xiaohong; Peñuelas, Josep

    2015-11-01

    Climate change is predicted to increase the aridity in the Mediterranean Basin and severely affect forest productivity and composition. The responses of forests to different timescales of drought, however, are still poorly understood because extreme and persistent moderate droughts can produce nonlinear responses in plants. We conducted a rainfall-manipulation experiment in a Mediterranean forest dominated by Quercus ilex, Phillyrea latifolia, and Arbutus unedo in the Prades Mountains in southern Catalonia from 1999 to 2014. The experimental drought significantly decreased forest aboveground-biomass increment (ABI), tended to increase the litterfall, and decreased aboveground net primary production throughout the 15 years of the study. The responses to the experimental drought were highly species-specific. A. unedo suffered a significant reduction in ABI, Q. ilex experienced a decrease during the early experiment (1999-2003) and in the extreme droughts of 2005-2006 and 2011-2012, and P. latifolia was unaffected by the treatment. The drought treatment significantly increased branch litterfall, especially in the extremely dry year of 2011, and also increased overall leaf litterfall. The drought treatment reduced the fruit production of Q. ilex, which affected seedling recruitment. The ABIs of all species were highly correlated with SPEI in early spring, whereas the branch litterfalls were better correlated with summer SPEIs and the leaf and fruit litterfalls were better correlated with autumn SPEIs. These species-specific responses indicated that the dominant species (Q. ilex) could be partially replaced by the drought-resistant species (P. latifolia). However, the results of this long-term study also suggest that the effect of drought treatment has been dampened over time, probably due to a combination of demographic compensation, morphological and physiological acclimation, and epigenetic changes. However, the structure of community (e.g., species composition

  11. Ecosystem, location, and climate effects on foliar secondary metabolites of lodgepole pine populations from central British Columbia.

    Science.gov (United States)

    Wallis, Christopher M; Huber, Dezene P W; Lewis, Kathy J

    2011-06-01

    Lodgepole pines, Pinus contorta Douglas ex Louden var. latifolia Engelm. ex S. Watson, are encountering increased abiotic stress and pest activity due to recent increases in temperature and changes in precipitation throughout their range. This tree species counters these threats by producing secondary metabolites, including phenolics and terpenoids. We examined foliar levels of lignin, soluble phenolics, monoterpenoids, sesquiterpenoids, and diterpenoids in 12 stands in British Columbia, Canada. We used these data to assess associations among foliar secondary metabolite levels and ecosystem, geographic, and climatic variables. Regressions were also performed to observe which combinations of variables best explained secondary metabolite variance. Stands of P. c. latifolia in the Coastal Western Hemlock and Interior Cedar/Hemlock biogeoclimatic zones had consistently greater foliar levels of almost all measured secondary metabolites than did other stands. Lignin was present in greater amounts in Boreal White/Black Spruce ecosystem (i.e., northern) stands than in southern stands, suggesting a role for this metabolite in pine survival in the boreal forest. Attempts to develop regression models with geographic and climatic variables to explain foliar secondary metabolite levels resulted in multiple models with similar predictive capability. Since foliar secondary metabolite levels appeared to vary most between stand ecosystem types and not as much due to geographic and climatic variables, metabolic profiles appeared best matched to the stress levels within local environments. It is unknown if differences in secondary metabolite levels are the result of genetic adaptation or phenotypic plasticity, but results from this and other studies suggest that both are important. These results are interpreted in light of ongoing efforts to assist in the migration of certain populations of P. c. latifolia northward in an effort to counter predicted effects of climate change.

  12. Glacial vicariance in the Pacific Northwest: evidence from a lodgepole pine mitochondrial DNA minisatellite for multiple genetically distinct and widely separated refugia.

    Science.gov (United States)

    Godbout, Julie; Fazekas, Aron; Newton, Craig H; Yeh, Francis C; Bousquet, Jean

    2008-05-01

    The Canadian side of the Pacific Northwest was almost entirely covered by ice during the last glacial maximum, which has induced vicariance and genetic population structure for several plant and animal taxa. Lodgepole pine (Pinus contorta Dougl. ex. Loud.) has a wide latitudinal and longitudinal distribution in the Pacific Northwest. Our main objective was to identify relictual signatures of glacial vicariance in the population structure of the species and search for evidence of distinct glacial refugia in the Pacific Northwest. A maternally inherited mitochondrial DNA minisatellite-like marker was used to decipher haplotype diversity in 91 populations of lodgepole pine located across the natural range. Overall population differentiation was sizeable (G(ST) = 0.365 and R(ST) = 0.568). Four relatively homogeneous groups of populations, possibly representative of as many genetically distinct glacial populations, were identified for the two main subspecies, ssp. latifolia and ssp. contorta. For ssp. contorta, one glacial lineage is suggested to have been located at high latitudes and possibly off the coast of mainland British Columbia (BC), while the other is considered to have been located south of the ice sheet along the Pacific coast. For ssp. latifolia, two genetically distinct glacial populations probably occurred south of the ice sheet: in the area bounded by the Cascades and Rocky Mountains ranges, and on the eastern side of the Rockies. A possible fifth refugium located in the Yukon may have also been present for ssp. latifolia. Zones of contact between these ancestral lineages were also apparent in interior and northern BC. These results indicate the role of the Queen Charlotte Islands and the Alexander Archipelago as a refugial zone for some Pacific Northwest species and the vicariant role played by the Cascades and the American Rocky Mountains during glaciation.

  13. A whole plant approach to evaluate the water use of mediterranean maquis species in a coastal dune ecosystem

    Science.gov (United States)

    Mereu, S.; Salvatori, E.; Fusaro, L.; Gerosa, G.; Muys, B.; Manes, F.

    2009-02-01

    An integrated approach has been used to analyse the water relations of three Mediterranean species, A. unedo L., Q. ilex L. and P. latifolia L. co-occurring in a coastal dune ecosystem. The approach considered leaf level gas exchange, sap flow measurements and structural adaptations between 15 May and 31 July 2007, and was necessary to capture the different response of the three species to the same environment. The complexity of the response was proportional to the complexity of the system, characterized by a sandy soil with a low water retention capacity and the presence of a water table. The latter did not completely prevent the development of a drought response, and species differences in this responses have been partially attributed to a different root distribution. Sap flow of A. unedo decreased rapidly in response to the decline of Soil Water Content, while that of Q. ilex decreased only moderately. Midday leaf water potential of P. latifolia and A. unedo was between 2.2 and 2.7 MPa through the measuring period, while in Q. ilex it reached a value of 3.4 MPa at the end of the season. A. unedo was the only species to decrease the leaf area to sapwood area ratio from 23.9±1.2 (May) to 15.2±1.5 (July), as a response to drought. A. unedo also underwent an almost stepwise loss on hydraulic conductivity, such a loss didn't occur for Q. ilex, while P. latifolia was able to slightly increase hydraulic conductivity, showing how different plant compartments coordinate differently between species as a response to drought. Such different coordination affects the gas exchange between vegetation and the atmosphere, and has implications for the response of the Mediterranean coastal dune ecosystems to climate change.

  14. studies on the effects of botanical extracts on the mycelial growth of ...

    African Journals Online (AJOL)

    ONYEKE CC

    1Department of Botany, University of Nigeria, Nsukka; 2Department of Crop Science, University of. Nigeria, Nsukka. (Received 24.2.11, Accepted 17.6.11). Abstract. The effects of crude ethanolic plant extracts of Garcinia kola seeds and Nauclea latifolia root on mycelial growth of seed-borne fungi of African yam bean at ...

  15. Ajayi et al., Afr J Tradit Complement Altern Med. (2016) 13(1):1-5 ...

    African Journals Online (AJOL)

    PROF ADEWUNMI

    Background: This study was designed to ascertain this claim and to investigate the possible mechanism of action in relation to their phytochemical contents, using crude extracts of N. latifolia and M. esculenta leaves on topical wound in a rat model of Type 1 diabetes. Methods and Materials: The leaves were air-dried under ...

  16. Mountain pine beetle attack alters the chemistry and flammability of lodgepole pine foliage

    Science.gov (United States)

    Wesley G. Page; Michael J. Jenkins; Justin B. Runyon

    2012-01-01

    During periods with epidemic mountain pine beetle (Dendroctonus ponderosae Hopkins) populations in lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) forests, large amounts of tree foliage are thought to undergo changes in moisture content and chemistry brought about by tree decline and death. However, many of the presumed changes have yet to be...

  17. Electron-electron interactions in disordered systems

    CERN Document Server

    Efros, AL

    1985-01-01

    ``Electron-Electron Interactions in Disordered Systems'' deals with the interplay of disorder and the Coulomb interaction. Prominent experts give state-of-the-art reviews of the theoretical and experimental work in this field and make it clear that the interplay of the two effects is essential, especially in low-dimensional systems.

  18. Narrow electron injector for ballistic electron spectroscopy

    International Nuclear Information System (INIS)

    Kast, M.; Pacher, C.; Strasser, G.; Gornik, E.

    2001-01-01

    A three-terminal hot electron transistor is used to measure the normal energy distribution of ballistic electrons generated by an electron injector utilizing an improved injector design. A triple barrier resonant tunneling diode with a rectangular transmission function acts as a narrow (1 meV) energy filter. An asymmetric energy distribution with its maximum on the high-energy side with a full width at half maximum of ΔE inj =10 meV is derived. [copyright] 2001 American Institute of Physics

  19. Temperature Dependence of the Spin-Hall Conductivity of a Two-Dimensional Impure Rashba Electron Gas in the Presence of Electron-Phonon and Electron-Electron Interactions

    Science.gov (United States)

    Yavari, H.; Mokhtari, M.; Bayervand, A.

    2015-03-01

    Based on Kubo's linear response formalism, temperature dependence of the spin-Hall conductivity of a two-dimensional impure (magnetic and nonmagnetic impurities) Rashba electron gas in the presence of electron-electron and electron-phonon interactions is analyzed theoretically. We will show that the temperature dependence of the spin-Hall conductivity is determined by the relaxation rates due to these interactions. At low temperature, the elastic lifetimes ( and are determined by magnetic and nonmagnetic impurity concentrations which are independent of the temperature, while the inelastic lifetimes ( and related to the electron-electron and electron-phonon interactions, decrease when the temperature increases. We will also show that since the spin-Hall conductivity is sensitive to temperature, we can distinguish the intrinsic and extrinsic contributions.

  20. Analytical local electron-electron interaction model potentials for atoms

    International Nuclear Information System (INIS)

    Neugebauer, Johannes; Reiher, Markus; Hinze, Juergen

    2002-01-01

    Analytical local potentials for modeling the electron-electron interaction in an atom reduce significantly the computational effort in electronic structure calculations. The development of such potentials has a long history, but some promising ideas have not yet been taken into account for further improvements. We determine a local electron-electron interaction potential akin to those suggested by Green et al. [Phys. Rev. 184, 1 (1969)], which are widely used in atom-ion scattering calculations, electron-capture processes, and electronic structure calculations. Generalized Yukawa-type model potentials are introduced. This leads, however, to shell-dependent local potentials, because the origin behavior of such potentials is different for different shells as has been explicated analytically [J. Neugebauer, M. Reiher, and J. Hinze, Phys. Rev. A 65, 032518 (2002)]. It is found that the parameters that characterize these local potentials can be interpolated and extrapolated reliably for different nuclear charges and different numbers of electrons. The analytical behavior of the corresponding localized Hartree-Fock potentials at the origin and at long distances is utilized in order to reduce the number of fit parameters. It turns out that the shell-dependent form of Green's potential, which we also derive, yields results of comparable accuracy using only one shell-dependent parameter

  1. Extracting electron backscattering coefficients from backscattered electron micrographs

    International Nuclear Information System (INIS)

    Zupanic, F.

    2010-01-01

    Electron backscattering micrographs possess the so-called Z-contrast, carrying information about the chemical compositions of phases present in microstructures. The intensity at a particular point in the backscattered electron micrograph is proportional to the signal detected at a corresponding point in the scan raster, which is, in turn, proportional to the electron backscattering coefficient of a phase at that point. This article introduces a simple method for extracting the electron backscattering coefficients of phases present in the microstructure, from the backscattered electron micrographs. This method is able to convert the micrograph's greyscale to the backscattering-coefficient-scale. The prerequisite involves the known backscattering coefficients for two phases in the micrograph. In this way, backscattering coefficients of other phases can be determined. The method is unable to determine the chemical compositions of phases or the presence of an element only from analysing the backscattered electron micrograph. Nevertheless, this method was found to be very powerful when combined with energy dispersive spectroscopy, and the calculations of backscattering coefficients. - Research Highlights: →A simple method for extracting the electron backscattering coefficients →The prerequisite is known backscattering coefficients for two phases →The information is complementary to the EDS-results. →This method is especially useful when a phase contains a light element (H, Li, Be, and B)

  2. PIC simulation of the electron-ion collision effects on suprathermal electrons

    International Nuclear Information System (INIS)

    Wu Yanqing; Han Shensheng

    2000-01-01

    The generation and transportation of suprathermal electrons are important to both traditional ICF scheme and 'Fast Ignition' scheme. The author discusses the effects of electron-ion collision on the generation and transportation of the suprathermal electrons by parametric instability. It indicates that the weak electron-ion term in the PIC simulation results in the enhancement of the collisional absorption and increase of the hot electron temperature and reduction in the maximum electrostatic field amplitude while wave breaking. Therefore the energy and distribution of the suprathermal electrons are changed. They are distributed more close to the phase velocity of the electrostatic wave than the case without electron-ion collision term. The electron-ion collision enhances the self-consistent field and impedes the suprathermal electron transportation. These factors also reduce the suprathermal electron energy. In addition, the authors discuss the effect of initial condition on PIC simulation to ensure that the results are correct

  3. Effect of ecological factors on the zonation of wetland vegetation

    Directory of Open Access Journals (Sweden)

    Richard Hrivnák

    2011-01-01

    Full Text Available The influence of some ecological factors to aquatic and marsh vegetation was studied during 1998-2000. Three basic vegetation units (Caricetum buekii, Typhetum latifoliae and Ceratophylletum submersi and three transitional communities were defined in the belt transect, which was established along the moisture gradient. The content of available soil nutrients in individual vegetation types differed only in case of the Ceratophyllum submersum community, where a higher magnesium and nitrogen content accumulated due to specific environmental conditions. Water and marsh vegetation is usually characterised by a pronounced spatial and temporal dynamics. In the studied area, its zonation was dependent from the terrain morphology, and both depth and duration of floods. The fluctuation of ground and surface water table during a three-year period caused changes in the occurrence and cover of several species (e.g. Carex buekii, Typha latifolia, aquatic macrophytes. Pronounced changes in the cover of some species occurred even within a single vegetation season due to the long-term sink of water table below the ground surface.

  4. Root biomass production in populations of six rooted macrophytes in response to Cu exposure: intra-specific variability versus constitutive-like tolerance.

    Science.gov (United States)

    Marchand, L; Nsanganwimana, F; Lamy, J B; Quintela-Sabaris, C; Gonnelli, C; Colzi, I; Fletcher, T; Oustrière, N; Kolbas, A; Kidd, P; Bordas, F; Newell, P; Alvarenga, P; Deletic, A; Mench, M

    2014-10-01

    Intra-specific variability of root biomass production (RP) of six rooted macrophytes, i.e. Juncus effusus, Phragmites australis, Schoenoplectus lacustris, Typha latifolia, Phalaris arundinacea, and Iris pseudacorus grown from clones, in response to Cu exposure was investigated. Root biomass production varied widely for all these macrophytes in control conditions (0.08 μM) according to the sampling site. Root biomass production of T. latifolia and I. pseudacorus in the 2.5-25 μM Cu range depended on the sampling location but not on the Cu dose in the growth medium. For P. australis, J. effusus, S. lacustris, and P. arundinacea, an intra-specific variability of RP depending on both the sampling location and the Cu-dose was evidenced. This intra-specific variability of RP depending on the sampling location and of Cu-tolerance for these last four species suggests that Cu constitutive tolerance for all rooted macrophytes is not a species-wide trait but it exhibits variability for some species. Copyright © 2014 Elsevier Ltd. All rights reserved.

  5. Spin Relaxation in GaAs: Importance of Electron-Electron Interactions

    Directory of Open Access Journals (Sweden)

    Gionni Marchetti

    2014-04-01

    Full Text Available We study spin relaxation in n-type bulk GaAs, due to the Dyakonov–Perel mechanism, using ensemble Monte Carlo methods. Our results confirm that spin relaxation time increases with the electronic density in the regime of moderate electronic concentrations and high temperature. We show that the electron-electron scattering in the non-degenerate regime significantly slows down spin relaxation. This result supports predictions by Glazov and Ivchenko. Most importantly, our findings highlight the importance of many-body interactions for spin dynamics: we show that only by properly taking into account electron-electron interactions within the simulations, results for the spin relaxation time—with respect to both electron density and temperature—will reach good quantitative agreement with corresponding experimental data. Our calculations contain no fitting parameters.

  6. Secondary mineralization in carious lesions of human dentin. Electron-probe, electron microscope, and electron diffraction studies

    Energy Technology Data Exchange (ETDEWEB)

    Ogiwara, H [Tokyo Dental Coll. (Japan)

    1975-02-01

    Dentinal carious lesions having a remineralized surface layer were studied by means electron-probe microanalysis, electron microscopy, electron diffraction. As the results of electron-probe study, F, Mg, and Na were found to be distributed mainly in the remineralized surface layer and S in the decalcified region where decreases in Ca, P, and Mg concentration were usually observed. The decrease in Mg concentration always started earlier than that of Ca and P concentration. Electron microscope and electron diffraction studies revealed that apatic crystals in the remineralized surface layer were much larger than those in the intact dentin. Although they were less conspicuous, crystals in the decalcified region also were larger than those in the intact region. Dentinal tubules, occluded by many crystals, were frequently seen during the observations. Crystals in the tubules varied in morphology, showing granular, needle, rhomboid, and tabular shapes. By means of electron diffraction, the granular- or needle-shaped crystals were identified as apatite and the rhomboid-shaped crystals as whitlockite. Some of the tabular-shaped crystals appeared to be cotacalcium phosphate.

  7. Electronic components

    CERN Document Server

    Colwell, Morris A

    1976-01-01

    Electronic Components provides a basic grounding in the practical aspects of using and selecting electronics components. The book describes the basic requirements needed to start practical work on electronic equipment, resistors and potentiometers, capacitance, and inductors and transformers. The text discusses semiconductor devices such as diodes, thyristors and triacs, transistors and heat sinks, logic and linear integrated circuits (I.C.s) and electromechanical devices. Common abbreviations applied to components are provided. Constructors and electronics engineers will find the book useful

  8. Ion- and electron-acoustic solitons in two-electron temperature space plasmas

    International Nuclear Information System (INIS)

    Lakhina, G. S.; Kakad, A. P.; Singh, S. V.; Verheest, F.

    2008-01-01

    Properties of ion- and electron-acoustic solitons are investigated in an unmagnetized multicomponent plasma system consisting of cold and hot electrons and hot ions using the Sagdeev pseudopotential technique. The analysis is based on fluid equations and the Poisson equation. Solitary wave solutions are found when the Mach numbers exceed some critical values. The critical Mach numbers for the ion-acoustic solitons are found to be smaller than those for electron-acoustic solitons for a given set of plasma parameters. The critical Mach numbers of ion-acoustic solitons increase with the increase of hot electron temperature and the decrease of cold electron density. On the other hand, the critical Mach numbers of electron-acoustic solitons increase with the increase of the cold electron density as well as the hot electron temperature. The ion-acoustic solitons have positive potentials for the parameters considered. However, the electron-acoustic solitons have positive or negative potentials depending whether the fractional cold electron density with respect to the ion density is greater or less than a certain critical value. Further, the amplitudes of both the ion- and electron-acoustic solitons increase with the increase of the hot electron temperature. Possible application of this model to electrostatic solitary waves observed on the auroral field lines by the Viking spacecraft is discussed

  9. Diffusive scattering of electrons by electron holes around injection fronts

    Science.gov (United States)

    Vasko, I. Y.; Agapitov, O. V.; Mozer, F. S.; Artemyev, A. V.; Krasnoselskikh, V. V.; Bonnell, J. W.

    2017-03-01

    Van Allen Probes have detected nonlinear electrostatic spikes around injection fronts in the outer radiation belt. These spikes include electron holes (EH), double layers, and more complicated solitary waves. We show that EHs can efficiently scatter electrons due to their substantial transverse electric fields. Although the electron scattering driven by EHs is diffusive, it cannot be evaluated via the standard quasi-linear theory. We derive analytical formulas describing local electron scattering by a single EH and verify them via test particle simulations. We show that the most efficiently scattered are gyroresonant electrons (crossing EH on a time scale comparable to the local electron gyroperiod). We compute bounce-averaged diffusion coefficients and demonstrate their dependence on the EH spatial distribution (latitudinal extent and spatial filling factor) and individual EH parameters (amplitude of electrostatic potential, velocity, and spatial scales). We show that EHs can drive pitch angle scattering of ≲5 keV electrons at rates 10-2-10-4 s-1 and, hence, can contribute to electron losses and conjugated diffuse aurora brightenings. The momentum and pitch angle scattering rates can be comparable, so that EHs can also provide efficient electron heating. The scattering rates driven by EHs at L shells L ˜ 5-8 are comparable to those due to chorus waves and may exceed those due to electron cyclotron harmonics.

  10. Pseudogap in the Eliashberg approach based on electron-phonon and electron-electron-phonon interaction

    Energy Technology Data Exchange (ETDEWEB)

    Szczesniak, R. [Institute of Physics, Czestochowa University of Technology (Poland); Institute of Physics, Jan Dlugosz University in Czestochowa (Poland); Durajski, A.P.; Duda, A.M. [Institute of Physics, Czestochowa University of Technology (Poland)

    2017-04-15

    The properties of the superconducting and the anomalous normal state were described by using the Eliashberg method. The pairing mechanism was reproduced with the help of the Hamiltonian, which models the electron-phonon and the electron-electron-phonon interaction (EEPh). The set of the Eliashberg equations, which determines the order parameter function (φ), the wave function renormalization factor (Z), and the energy shift function (χ), was derived. It was proven that for the sufficiently large values of the EEPh potential, the doping dependence of the order parameter (φ/Z) has the analogous course to that observed experimentally in cuprates. The energy gap in the electron density of states is induced by Z and χ - the contribution from φ is negligible. The electron density of states possesses the characteristic asymmetric form and the pseudogap is observed above the critical temperature. (copyright 2017 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Carbon Nanotube Electron Gun

    Science.gov (United States)

    Nguyen, Cattien V. (Inventor); Ribaya, Bryan P. (Inventor)

    2013-01-01

    An electron gun, an electron source for an electron gun, an extractor for an electron gun, and a respective method for producing the electron gun, the electron source and the extractor are disclosed. Embodiments provide an electron source utilizing a carbon nanotube (CNT) bonded to a substrate for increased stability, reliability, and durability. An extractor with an aperture in a conductive material is used to extract electrons from the electron source, where the aperture may substantially align with the CNT of the electron source when the extractor and electron source are mated to form the electron gun. The electron source and extractor may have alignment features for aligning the electron source and the extractor, thereby bringing the aperture and CNT into substantial alignment when assembled. The alignment features may provide and maintain this alignment during operation to improve the field emission characteristics and overall system stability of the electron gun.

  12. Molecular electron affinities

    International Nuclear Information System (INIS)

    Fukuda, E.K.

    1983-01-01

    Molecular electron affinities have historically been difficult quantities to measure accurately. These difficulties arise from differences in structure between the ion and neutral as well as the existence of excited negative ion states. To circumvent these problems, relative electron affinities were determined in this dissertation by studying equilibrium electron transfer reactions using a pulsed ion cyclotron resonance (ICR) spectrometer. Direct measurement of ion and neutral concentrations for reactions of the general type, A - + B = B - + A, allow calculation of the equilibrium constant and, therefore, the free energy change. The free energy difference is related to the difference in electron affinities between A and B. A relative electron affinity scale covering a range of about 45 kcal/mol was constructed with various substituted p-benzoquinones, nitrobenzenes, anhydrides, and benzophenones. To assign absolute electron affinities, various species with accurately known electron affinities are tied to the scale via ion-cyclotron double resonance bracketing techniques. After the relative scale is anchored to these species with well-known electron affinities, the scale is then used as a check on other electron affinity values as well as generating new electron affinity values. Many discrepancies were found between the electron affinities measured using the ICR technique and previous literature determinations

  13. Nonambipolar electron source

    International Nuclear Information System (INIS)

    Longmier, B.; Baalrud, S.; Hershkowitz, N.

    2006-01-01

    A radio frequency (rf) plasma-based electron source that does not rely on electron emission at a cathode surface has been constructed. All of the random electron flux incident on an exit aperture is extracted through an electron sheath resulting in total nonambipolar flow within the device when the ratio of the ion loss area to the electron loss area is approximately equal to the square root of the ratio of the ion mass to the electron mass, and the ion sheath potential drop at the chamber walls is much larger than T e /e. The nonambipolar electron source (NES) has an axisymmetric magnetic field of 100 G at the extraction aperture that results in a uniform plasma potential across the aperture, allowing the extraction of all the incident electron flux without the use of grids. A prototype NES has produced 15 A of continuous electron current, using 15 SCCM (SCCM denotes cubic centimeter per minute at STP) Ar, 1200 W rf power at 13.56 MHz, and 6 times gas utilization. Alternatively 8 A of electron current can be produced, using 3 SCCM Ar at 1200 W rf and 20 times gas utilization. NES could replace hollow cathode electron sources in a wide variety of applications

  14. Electron-plasmon model in the electron liquid theory

    Directory of Open Access Journals (Sweden)

    M.V.Vavrukh

    2005-01-01

    Full Text Available Here we propose an accurate approach to the description of the electron liquid model in the electron and plasmon terms. Our ideas in the present paper are close to the conception of the collective variables which was developed in the papers of Bohm and Pines. However we use another body of mathematics in the transition to the expanded space of variable particles and plasmons realized by the transition operator. It is evident that in the Random Phase Approximation (RPA, the model which consists of two interactive subsystems of electrons and plasmons is equivalent to the electron liquid model with Coulomb interaction.

  15. Polymer electronics

    CERN Document Server

    Hsin-Fei, Meng

    2013-01-01

    Polymer semiconductor is the only semiconductor that can be processed in solution. Electronics made by these flexible materials have many advantages such as large-area solution process, low cost, and high performance. Researchers and companies are increasingly dedicating time and money in polymer electronics. This book focuses on the fundamental materials and device physics of polymer electronics. It describes polymer light-emitting diodes, polymer field-effect transistors, organic vertical transistors, polymer solar cells, and many applications based on polymer electronics. The book also disc

  16. A direct electron detector for time-resolved MeV electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Vecchione, T.; Denes, P.; Jobe, R. K.; Johnson, I. J.; Joseph, J. M.; Li, R. K.; Perazzo, A.; Shen, X.; Wang, X. J.; Weathersby, S. P.; Yang, J.; Zhang, D.

    2017-03-01

    The introduction of direct electron detectors enabled the structural biology revolution of cryogenic electron microscopy. Direct electron detectors are now expected to have a similarly dramatic impact on time-resolved MeV electron microscopy, particularly by enabling both spatial and temporal jitter correction. Here we report on the commissioning of a direct electron detector for time-resolved MeV electron microscopy. The direct electron detector demonstrated MeV single electron sensitivity and is capable of recording megapixel images at 180 Hz. The detector has a 15-bit dynamic range, better than 30-μmμm spatial resolution and less than 20 analogue-to-digital converter count RMS pixel noise. The unique capabilities of the direct electron detector and the data analysis required to take advantage of these capabilities are presented. The technical challenges associated with generating and processing large amounts of data are also discussed.

  17. Coherent Electron Focussing in a Two-Dimensional Electron Gas.

    NARCIS (Netherlands)

    Houten, H. van; Wees, B.J. van; Mooij, J.E.; Beenakker, C.W.J.; Williamson, J.G.; Foxon, C.T.

    1988-01-01

    The first experimental realization of ballistic point contacts in a two-dimensional electron gas for the study of transverse electron focussing by a magnetic field is reported. Multiple peaks associated with skipping orbits of electrons reflected specularly by the channel boundary are observed. At

  18. Contribución a la flora giennense

    OpenAIRE

    Blanca López, Gabriel; Díaz de la Guardia Guerrero, Consuelo; Valle, Francisco

    1985-01-01

    En el presente trabajo se comenta la ecología, corología y taxonomía de varias especies de la provincia de Jaén. Muchas de ellas se citan por vez primera en dicha provincia: Paronychia echinulata Chater, Silene stricta L., Leucojum trichophyllum Schouboe, Merendera androcymbioides Valdés, Romulea ramiflora Ten., Barlia robertiana (Loisel) W. Greuter, Sera�pias cordigera L., etc. In this paper we comment on the ecologic, chorologic and taxonomic behavior of several taxa in the province of J...

  19. A study on the secondary electrons in a clinical electron beam

    International Nuclear Information System (INIS)

    Krithivas, G.; Rao, S.N.

    1989-01-01

    The central axis dose of a 12 MeV clinical electron beam is investigated in terms of an axial component due to primary electrons in the central ray and a lateral component due to secondary electrons originating from multiple scattering of electrons in the off-axis rays. To this effect secondary electron fluence measurements in a polystyrene medium irradiated with a collimated beam are made with a sensitive diode detector. This leads to a construction of secondary electron depth-dose profiles for beam sizes of diameters ranging from 1.7 to 17.4 cm. The results indicate that the lateral electrons account for 25% of the dose in the therapeutic region. For these electrons, the depth of dose maximum is correlated with diffusion depth and maximum lateral excursion in the medium. Dose component due to backscatter electrons at depths is also investigated using a thin-window parallel-plate ion chamber. The role of lateral and backscatter electrons in characterising central axis per cent depth-dose is discussed. (author)

  20. Electronics for dummies

    CERN Document Server

    Shamieh

    2015-01-01

    Explore the basic concepts of electronics, build your electronics workbench, and begin creating fun electronics projects right away! Electronics For Dummies, 3rd Edition is your guide to the world of electronics. Spanning circuitry, wiring, robotics, transmitters, amplifiers, and more, this book demystifies electricity basics and beyond. The third edition offers new content revised to reflect the latest advancements in the electronics field, and it offers full color project examples to spark your creativity and inspire you to put your new skills to use! Packed with projects that can be comple

  1. Electron holography

    CERN Document Server

    Tonomura, Akira

    1993-01-01

    Holography was devised for breaking through the resolution limit of electron microscopes The advent of a "coherent" field emission electron beam has enabled the use of Electron Holography in various areas of magnetic domain structures observation, fluxon observation in superconductors, and fundamental experiments in physics which have been inaccessible using other techniques After examining the fundamentals of electron holography and its applications to the afore mentioned fields, a detailed discussion of the Aharonov-Bohm effect and the related experiments is presented Many photographs and illustrations are included to elucidate the text

  2. Comprehensive analysis of electron correlations in three-electron atoms

    International Nuclear Information System (INIS)

    Morishita, T.; Lin, C.D.

    1999-01-01

    We study the electron correlations in singly, doubly, and triply excited states of a three-electron atom. While electron correlation in general is weak for singly excited states, correlation plays major roles in determining the characteristics of doubly and triply excited states. Using the adiabatic approximation in hyperspherical coordinates, we show that the distinction between singly, doubly, and triply excited states is determined by the radial correlations, while finer distinctions within doubly or triply excited states lie in the angular correlations. Partial projections of the body-fixed frame wave functions are used to demonstrate the characteristic nodal surfaces which provide clues to the energy ordering of the states. We show that doubly excited states of a three-electron atom exhibit correlations that are similar to the doubly excited states of a two-electron atom. For the triply excited states, we show that the motion of the three electrons resemble approximately that of a symmetric top. copyright 1999 The American Physical Society

  3. Advanced electron beam techniques

    International Nuclear Information System (INIS)

    Hirotsu, Yoshihiko; Yoshida, Yoichi

    2007-01-01

    After 100 years from the time of discovery of electron, we now have many applications of electron beam in science and technology. In this report, we review two important applications of electron beam: electron microscopy and pulsed-electron beam. Advanced electron microscopy techniques to investigate atomic and electronic structures, and pulsed-electron beam for investigating time-resolved structural change are described. (author)

  4. Ajayi et al (24).cdr

    African Journals Online (AJOL)

    Timothy Ademakinwa

    In this study, an assessment of the analgesic potential of Zea mays L., Nauclea latifolia Sm leaf; leaf and stalk of. Manihot esculenta Crantz was made. Pain was induced by 0.6% acetic acid in high fat diet-manipulated, alloxan- induced hyperglycaemic rats. Paracetamol® (65 mg/kgBW) served as positive control, while olive ...

  5. Chesapeake Bay Low Freshwater Inflow Study. Biota Assessment. Phase I. Appendices.

    Science.gov (United States)

    1980-08-01

    Resources Coastal Resources Power Plant Siting Maryland Geological Survey Maryland Environmental Health Administration university of Maryland Marine...are very common: Acorus calamus Polygonum spp. Hibiscus palustris Pontederia cordata Leersia spp. Sagittaria latifolia Nuphar leiteum Typha... Hibiscus ) penetrate to mesohaline salinities. In general, the fresh water marsh associations are limited to areas upstream of 3 - 50Xsalinity

  6. Author Details

    African Journals Online (AJOL)

    Kumar, M. Vol 78, No 1 (2008) - Articles Effect of aspect on distribution pattern of Anogeissus latifolia (Wall Ex Bedd) in subtropical belt of Garhwal Himalaya, India Abstract. ISSN: 2408-8137. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's ...

  7. Field test of foliar-spray herbicides to control mountain laurel in mature mixed-oak forests in western Maryland

    Science.gov (United States)

    Gary W. Miller; Patrick H. Brose; Jeffrey D. Kochenderfer; James N. Kochenderfer; Kurt W. Gottschalk; John R. Denning

    2016-01-01

    Successful oak (Quercus spp.) regeneration requires the presence of competitive sources of oak reproduction before parent oaks are harvested. Mountain laurel (Kalmia latifolia) in the understory of many Appalachian forests prevents new oak seedlings from receiving adequate sunlight to survive and grow into competitive size classes. This study examined the efficacy of...

  8. Leaf area and tree increment dynamics of even-aged and multiaged lodgepole pine stands in Montana

    Science.gov (United States)

    Cassandra L. Kollenberg; Kevin L. O' Hara

    1999-01-01

    Age structure and distribution of leaf area index (LAI) of even and multiaged lodgepole pine (Pinus contorta var. latifolia Engelm.) stands were examined on three study areas in western and central Montana. Projected leaf area was determined based on a relationship with sapwood cross-sectional area at breast height. Stand structure and LAI varied considerably between...

  9. Effects of electron-electron interactions on electronic transport in disordered systems

    International Nuclear Information System (INIS)

    Foley, Simon Timothy

    2002-01-01

    This thesis is concerned with the role of electron-electron interactions on electronic transport in disordered systems. We first consider a novel non-linear sigma model in order to microscopically treat the effects of disorder and electronic interaction. We successfully reproduce the perturbative results for the zero-bias anomaly and the interaction correction to the conductivity in a weakly disordered system, and discuss possible directions for future work. Secondly we consider the fluctuations of the dephasing rate for a closed diffusive and quantum dot system. Using the Keldysh technique we derive an expression for the inelastic scattering rate with which we self-consistently obtain the fluctuations in the dephasing rate. For the diffusive regime we find the relative fluctuations is given by F ∼ (L φ /L) 2 /g 2 , where g is the dimensionless conductance, L φ is the dephasing length and L is the sample size. For the quantum dot regime we find a perturbative divergence due to the presence of the zero mode. By mapping divergent diagrams to those for the two-level correlation function, we conjecture the existence of an exact relation between the two. Finally we discuss the consequences of this relation. (author)

  10. Characteristics of trapped electrons and electron traps in single crystals

    International Nuclear Information System (INIS)

    Budzinski, E.E.; Potter, W.R.; Potienko, G.; Box, H.C.

    1979-01-01

    Two additional carbohydrates are reported whose crystal structures trap electrons intermolecularly in single crystals x irradiated at low temperature, namely sucrose and rhamnose. Five carbohydrate and polyhydroxy compounds are now known which exhibit this phenomenon. The following characteristics of the phenomenon were investigated: (1) the hyperfine couplings of the electron with protons of the polarized hydroxy groups forming the trap; (2) the distances between these protons and the trapped electron; (3) the spin density of the electron at the protons and (4) the relative stabilities of the electron trapped in various crystal structures

  11. Electron-electron scattering in linear transport in two-dimensional systems

    DEFF Research Database (Denmark)

    Hu, Ben Yu-Kuang; Flensberg, Karsten

    1996-01-01

    We describe a method for numerically incorporating electron-electron scattering in quantum wells for small deviations of the distribution function from equilibrium, within the framework of the Boltzmann equation. For a given temperature T and density n, a symmetric matrix needs to be evaluated only...... once, and henceforth it can be used to describe electron-electron scattering in any Boltzmann equation linear-response calculation for that particular T and n. Using this method, we calculate the distribution function and mobility for electrons in a quantum well, including full finite...

  12. Terahertz Plasma Waves in Two Dimensional Quantum Electron Gas with Electron Scattering

    International Nuclear Information System (INIS)

    Zhang Liping

    2015-01-01

    We investigate the Terahertz (THz) plasma waves in a two-dimensional (2D) electron gas in a nanometer field effect transistor (FET) with quantum effects, the electron scattering, the thermal motion of electrons and electron exchange-correlation. We find that, while the electron scattering, the wave number along y direction and the electron exchange-correlation suppress the radiation power, but the thermal motion of electrons and the quantum effects can amplify the radiation power. The radiation frequency decreases with electron exchange-correlation contributions, but increases with quantum effects, the wave number along y direction and thermal motion of electrons. It is worth mentioning that the electron scattering has scarce influence on the radiation frequency. These properties could be of great help to the realization of practical THz plasma oscillations in nanometer FET. (paper)

  13. Oblique electron cyclotron emission for electron distribution studies (invited)

    International Nuclear Information System (INIS)

    Preische, S.; Efthimion, P.C.; Kaye, S.M.

    1997-01-01

    Electron cyclotron emission (ECE) at an oblique angle to the magnetic field provides a means of probing the electron distribution function both in energy and physical space through changes in and constraints on the relativistic electron cyclotron resonance condition. Diagnostics based on this Doppler shifted resonance are able to study a variety of electron distributions through changes in the location of the resonance in physical or energy space accomplished by changes in the viewing angle and frequency, and the magnetic field. For the case of observation across a changing magnetic field, such as across the tokamak midplane, the constraint on the resonance condition for real solutions to the dispersion relation can constrain the physical location of optically thin emission. A new Oblique ECE diagnostic was installed and operated on the PBX-M tokamak for the study of energetic electrons during lower hybrid current drive. It has a view 33 degree with respect to perpendicular in the tokamak midplane, receives second harmonic X-mode emission, and is constrained to receive single pass emission by SiC viewing dumps on the tokamak walls. Spatial localization of optically thin emission from superthermal electrons (50 endash 100 keV) was obtained by observation of emission upshifted from a thermal cyclotron harmonic. The localized measurements of the electron energy distribution and the superthermal density profile made by this diagnostic demonstrate its potential to study the spatial transport of energetic electrons on fast magnetohydrodynamic time scales or anomalous diffusion time scales. Oblique ECE can also be used to study electron distributions that may have a slight deviation from a Maxwellian by localizing the emission in energy space. (Abstract Truncated)

  14. Electron microscopy of boron carbide before and after electron irradiation

    International Nuclear Information System (INIS)

    Stoto, T.; Zuppiroli, L.; Beauvy, M.; Athanassiadis, T.

    1984-06-01

    The microstructure of boron carbide has been studied by electron microscopy and related to the composition of the material. After electron irradiations in an usual transmission electron microscope and in a high voltage electron microscope at different temperatures and fluxes no change of these microstructures have been observed but a sputtering of the surface of the samples, which has been studied quantitatively [fr

  15. Electron Cyclotron Resonances in Electron Cloud Dynamics

    International Nuclear Information System (INIS)

    Celata, Christine; Celata, C.M.; Furman, Miguel A.; Vay, J.-L.; Yu, Jennifer W.

    2008-01-01

    We report a previously unknown resonance for electron cloud dynamics. The 2D simulation code 'POSINST' was used to study the electron cloud buildup at different z positions in the International Linear Collider positron damping ring wiggler. An electron equilibrium density enhancement of up to a factor of 3 was found at magnetic field values for which the bunch frequency is an integral multiple of the electron cyclotron frequency. At low magnetic fields the effects of the resonance are prominent, but when B exceeds ∼(2 pi mec/(elb)), with lb = bunch length, effects of the resonance disappear. Thus short bunches and low B fields are required for observing the effect. The reason for the B field dependence, an explanation of the dynamics, and the results of the 2D simulations and of a single-particle tracking code used to elucidate details of the dynamics are discussed

  16. Role of electron-electron interactions in the RKKY theory of magnetism

    International Nuclear Information System (INIS)

    Cooke, J.F.

    1978-10-01

    The theory of magnetism in heavy rare earth metals is based on the RKKY theory. In this formalism the indirect exchange interaction between the local 4f spins is mediated by the conduction electrons. When carried to second order in the 4f-conduction electron interaction, traditional perturbation theory leads to a Heisenberg-like interaction between the local spins which depends on the electronic energy bands and 4f-conduction electron exchange matrix elements. This derivation neglects the detailed behavior of electron-electron interaction within the conduction band, which is known to be important in metallic systems. By using an equation of motion method, an expression for the inelastic neutron scattering cross-section has been derived which includes, in an approximate way, this electron-electron interaction. The results of this calculation indicate that spin-wave peaks can be broadened and shifted if the spin-wave band lies near the conduction electron Stoner continuum. The origin of this effect is similar to that found in itinerant electron systems where the spin-wave band actually intersects the Stoner continuum, resulting in the disappearance of the spin-wave mode

  17. Role of electron-electron interactions in the RKKY theory of magnetism

    International Nuclear Information System (INIS)

    Cooke, J.F.

    1979-01-01

    The theory of magnetism in heavy rare earth metals is based on the RKKY theory. In this formalism the indirect exchange interaction between the local 4f spins is mediated by the conduction electrons. When carried to second order in the 4f-conduction electron interaction, traditional pertubation theory leads to a Heisenberg-like interaction between the local spins which depends on the electronic energy bands and 4f-conduction electron exchange matrix elements. This derivation neglects the detailed behavior of electron-electron interaction within the conduction band, which is known to be important in metallic systems. By using an equation of motion method, an expression for the inelastic neutron scattering cross-section has been derived which includes, in an approximate way, this electron-electron interaction. The results of this calculation indicate that spin-wave peaks can be broadened and shifted if the spin-wave band lies near the conduction electron Stoner continuum. The origin of this effect is similar to that found in itinerant electron systems where the spin-wave band actually intersects the Stoner continuum, resulting in the disappearance of the spin-wave mode

  18. Electron acoustic solitary waves in unmagnetized two electron population dense plasmas

    International Nuclear Information System (INIS)

    Mahmood, S.; Masood, W.

    2008-01-01

    The electron acoustic solitary waves are studied in unmagnetized two population electron quantum plasmas. The quantum hydrodynamic model is employed with the Sagdeev potential approach to describe the arbitrary amplitude electron acoustic waves in a two electron population dense Fermi plasma. It is found that hot electron density hump structures are formed in the subsonic region in such type of quantum plasmas. The wave amplitude as well as the width of the soliton are increased with the increase of percentage presence of cold (thinly populated) electrons in a multicomponent quantum plasma. It is found that an increase in quantum diffraction parameter broadens the nonlinear structure. Furthermore, the amplitude of the nonlinear electron acoustic wave is found to increase with the decrease in Mach number. The numerical results are also presented to understand the formation of solitons in two electron population Fermi plasmas.

  19. Advances in imaging and electron physics the scanning transmission electron microscope

    CERN Document Server

    Hawkes, Peter W

    2009-01-01

    Advances in Imaging and Electron Physics merges two long-running serials--Advances in Electronics and Electron Physics and Advances in Optical and Electron Microscopy. This series features extended articles on the physics of electron devices (especially semiconductor devices), particle optics at high and low energies, microlithography, image science and digital image processing, electromagnetic wave propagation, electron microscopy, and the computing methods used in all these domains.  This particular volume presents several timely articles on the scanning transmission electron microscope. Updated with contributions from leading international scholars and industry experts Discusses hot topic areas and presents current and future research trends Provides an invaluable reference and guide for physicists, engineers and mathematicians.

  20. Attractive electron correlation in wide band gap semiconductors by electron-photon interaction

    International Nuclear Information System (INIS)

    Takeda, Hiroyuki; Yoshino, Katsumi

    2004-01-01

    We theoretically demonstrate attractive electron correlation in wide band gap semiconductors by electron-photon interaction. At low temperature, wavevectors of electromagnetic waves absorbed in wide band gap semiconductors cannot be neglected for wavevectors of electron waves; that is, electromagnetic waves affect the movements of electrons. In particular, attractive interaction occurs between two electrons when one electron changes from a valence band to a conduction band and the other electron changes from a conduction band to a valence band

  1. Electronic Publishing or Electronic Information Handling?

    Science.gov (United States)

    Heck, A.

    The current dramatic evolution in information technology is bringing major modifications in the way scientists communicate. The concept of 'electronic publishing' is too restrictive and has often different, sometimes conflicting, interpretations. It is thus giving way to the broader notion of 'electronic information handling' encompassing the diverse types of information, the different media, as well as the various communication methodologies and technologies. New problems and challenges result also from this new information culture, especially on legal, ethical, and educational grounds. The procedures for validating 'published material' and for evaluating scientific activities will have to be adjusted too. 'Fluid' information is becoming a common concept. Electronic publishing cannot be conceived without link to knowledge bases nor without intelligent information retrieval tools.

  2. Theoretical study of the interplay of electron-electron interaction and disorder

    International Nuclear Information System (INIS)

    Brezini, A.; Behilil, S.

    1988-10-01

    A disordered Hubbard model with diagonal disorder is used to investigate the electron localization effects associated with both disorder and electron-electron interaction. Extensive results are reported on the ground state properties and compared to other theories. Two regimes have been found: when the electron-electron interaction u is greater than the disorder parameter w and when u < w. (author). 18 refs, 4 figs

  3. Defining Electron Bifurcation in the Electron-Transferring Flavoprotein Family.

    Science.gov (United States)

    Garcia Costas, Amaya M; Poudel, Saroj; Miller, Anne-Frances; Schut, Gerrit J; Ledbetter, Rhesa N; Fixen, Kathryn R; Seefeldt, Lance C; Adams, Michael W W; Harwood, Caroline S; Boyd, Eric S; Peters, John W

    2017-11-01

    Electron bifurcation is the coupling of exergonic and endergonic redox reactions to simultaneously generate (or utilize) low- and high-potential electrons. It is the third recognized form of energy conservation in biology and was recently described for select electron-transferring flavoproteins (Etfs). Etfs are flavin-containing heterodimers best known for donating electrons derived from fatty acid and amino acid oxidation to an electron transfer respiratory chain via Etf-quinone oxidoreductase. Canonical examples contain a flavin adenine dinucleotide (FAD) that is involved in electron transfer, as well as a non-redox-active AMP. However, Etfs demonstrated to bifurcate electrons contain a second FAD in place of the AMP. To expand our understanding of the functional variety and metabolic significance of Etfs and to identify amino acid sequence motifs that potentially enable electron bifurcation, we compiled 1,314 Etf protein sequences from genome sequence databases and subjected them to informatic and structural analyses. Etfs were identified in diverse archaea and bacteria, and they clustered into five distinct well-supported groups, based on their amino acid sequences. Gene neighborhood analyses indicated that these Etf group designations largely correspond to putative differences in functionality. Etfs with the demonstrated ability to bifurcate were found to form one group, suggesting that distinct conserved amino acid sequence motifs enable this capability. Indeed, structural modeling and sequence alignments revealed that identifying residues occur in the NADH- and FAD-binding regions of bifurcating Etfs. Collectively, a new classification scheme for Etf proteins that delineates putative bifurcating versus nonbifurcating members is presented and suggests that Etf-mediated bifurcation is associated with surprisingly diverse enzymes. IMPORTANCE Electron bifurcation has recently been recognized as an electron transfer mechanism used by microorganisms to maximize

  4. Effects of electron-electron interactions on the electron distribution function of a plasma in the presence of an external electric field

    International Nuclear Information System (INIS)

    Molinari, V.G.; Pizzio, F.; Spiga, G.

    1979-01-01

    The electron distribution function, the electron temperature and some transport parameters (electrical conductivity and energy flow coefficient) are obtained starting from the nonlinear Boltzmann equation for a plasma under the action of an external electric field. The Fokker-Planck approximation is used for electron-electron and electron-ion interactions. The effects of electron-electron collisions are studied for different values of collision frequencies and electric field. (author)

  5. Electron-excited molecule interactions

    International Nuclear Information System (INIS)

    Christophorou, L.G.; Tennessee Univ., Knoxville, TN

    1991-01-01

    In this paper the limited but significant knowledge to date on electron scattering from vibrationally/rotationally excited molecules and electron scattering from and electron impact ionization of electronically excited molecules is briefly summarized and discussed. The profound effects of the internal energy content of a molecule on its electron attachment properties are highlighted focusing in particular on electron attachment to vibrationally/rotationally and to electronically excited molecules. The limited knowledge to date on electron-excited molecule interactions clearly shows that the cross sections for certain electron-molecule collision processes can be very different from those involving ground state molecules. For example, optically enhanced electron attachment studies have shown that electron attachment to electronically excited molecules can occur with cross sections 10 6 to 10 7 times larger compared to ground state molecules. The study of electron-excited molecule interactions offers many experimental and theoretical challenges and opportunities and is both of fundamental and technological significance. 54 refs., 15 figs

  6. Seeing with electrons

    International Nuclear Information System (INIS)

    Nellist, P.

    2006-01-01

    Commercially available lens correctors are extending the reach of electron microscopes to unprecedented atomic scales, as Peter Nellist describes. The electron microscope was invented in 1933 and is based on the principle that electrons have a wavelength that is inversely proportional to their momentum. There are two basic types: transmission electron microscopes and scanning electron microscopes, plus a hybrid of the two. The lenses in an electron microscope are provided by electromagnetic fields, but they suffer from spherical aberration. The addition of octupole and quadrupole corrector fields has improved the resolution of the electron microscope to better than 0.1 nm in the last decade. The next step is to correct for chromatic aberration, after which the resolution of the microscope will probably be limited by the size of the atom itself. (U.K.)

  7. Introduction to electronics

    CERN Multimedia

    CERN. Geneva

    2005-01-01

    Electronics in HEP experiments: specificities and evolution The Art of Electronics: is there something beyond Ohm's law? Basic building blocks of Analog electronics: quickly understanding a schematic Charge preamps, current preamps and future preamps, shaping and the rest Electronics noise: fundamental and practical Evolution of technology: ASICs, FPGAs...

  8. Multiple electron generation in a sea of electronic states

    Science.gov (United States)

    Witzel, Wayne; Shabaev, Andrew; Efros, Alexander; Hellberg, Carl; Verne, Jacobs

    2009-03-01

    In traditional bulk semiconductor photovoltaics (PVs), each photon may excite a single electron-hole, wasting excess energy beyond the band-gap as heat. In nanocrystals, multiple excitons can be generated from a single photon, enhancing the PV current. Multiple electron generation (MEG) may result from Coulombic interactions of the confined electrons. Previous investigations have been based on incomplete or over-simplified electronic-state representations. We present results of quantum simulations that include hundreds of thousands of configuration states and show how the complex dynamics, even in a closed electronic system, yields a saturated MEG effect on a femtosecond timescale. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  9. Electron collision cross sections and electron swarm parameters for gas molecules

    International Nuclear Information System (INIS)

    Hayashi, Makoto

    1986-01-01

    Elastic and inelastic electron collision cross sections for molecules which interest in radiation research have been determined from available electron beam and electron swarm data by utilizing the Boltzmann equation and Monte Carlo simulation method. Electron drift velocity data which interest in radiation Pysics have been discussed and some calculated results of electron drift velocity data for CF 4 and CF 4 -inert gases mixtures will be presented. (author)

  10. Dampening effects of long-term experimental drought on growth and mortality rates of a Holm oak forest.

    Science.gov (United States)

    Barbeta, Adrià; Ogaya, Romà; Peñuelas, Josep

    2013-10-01

    Forests respond to increasing intensities and frequencies of drought by reducing growth and with higher tree mortality rates. Little is known, however, about the long-term consequences of generally drier conditions and more frequent extreme droughts. A Holm oak forest was exposed to experimental rainfall manipulation for 13 years to study the effect of increasing drought on growth and mortality of the dominant species Quercus ilex, Phillyrea latifolia, and Arbutus unedo. The drought treatment reduced stem growth of A. unedo (-66.5%) and Q. ilex (-17.5%), whereas P. latifolia remained unaffected. Higher stem mortality rates were noticeable in Q. ilex (+42.3%), but not in the other two species. Stem growth was a function of the drought index of early spring in the three species. Stem mortality rates depended on the drought index of winter and spring for Q. ilex and in spring and summer for P. latifolia, but showed no relation to climate in A. unedo. Following a long and intense drought (2005-2006), stem growth of Q. ilex and P. latifolia increased, whereas it decreased in A. unedo. Q. ilex also enhanced its survival after this period. Furthermore, the effect of drought treatment on stem growth in Q. ilex and A. unedo was attenuated as the study progressed. These results highlight the different vulnerabilities of Mediterranean species to more frequent and intense droughts, which may lead to partial species substitution and changes in forest structure and thus in carbon uptake. The response to drought, however, changed over time. Decreased intra- and interspecific competition after extreme events with high mortality, together with probable morphological and physiological acclimation to drought during the study period, may, at least in the short term, buffer forests against drier conditions. The long-term effects of drought consequently deserve more attention, because the ecosystemic responses are unlikely to be stable over time.Nontechnical summaryIn this study, we

  11. Electronic payment systems

    OpenAIRE

    Mláka, Michal

    2010-01-01

    This bachelor thesis analysis issue of electronic payment systems. It discusses their use for payments on the internet and sending funds via e-mail. The first part is devoted to the theoretical definition and legislation of the issuance of electronic money and activities of electronic money institutions. The main part of the work clearly focuses on the use of e-wallets, which is an integral part of electronic payment systems. E-wallet of electronic payment system Moneybookers is considered as...

  12. Wigner-like crystallization of Anderson-localized electron systems with low electron densities

    CERN Document Server

    Slutskin, A A; Pepper, M

    2002-01-01

    We consider an electron system under conditions of strong Anderson localization, taking into account interelectron long-range Coulomb repulsion. We establish that at sufficiently low electron densities and sufficiently low temperatures the Coulomb electron interaction brings about ordering of the Anderson-localized electrons into a structure that is close to an ideal (Wigner) crystal lattice, provided the dimension of the system is > 1. This Anderson-Wigner glass (AWG) is a new macroscopic electron state that, on the one hand, is beyond the conventional Fermi glass concept, and on the other hand, qualitatively differs from the known 'plain' Wigner glass (inherent in self-localized electron systems) in that the random slight electron displacements from the ideal crystal sites essentially depend on the electron density. With increasing electron density the AWG is found to turn into the plain Wigner glass or Fermi glass, depending on the width of the random spread of the electron levels. It is shown that the res...

  13. Excess electrons in methanol clusters: Beyond the one-electron picture

    Science.gov (United States)

    Pohl, Gábor; Mones, Letif; Turi, László

    2016-10-01

    We performed a series of comparative quantum chemical calculations on various size negatively charged methanol clusters, ("separators=" CH 3 OH ) n - . The clusters are examined in their optimized geometries (n = 2-4), and in geometries taken from mixed quantum-classical molecular dynamics simulations at finite temperature (n = 2-128). These latter structures model potential electron binding sites in methanol clusters and in bulk methanol. In particular, we compute the vertical detachment energy (VDE) of an excess electron from increasing size methanol cluster anions using quantum chemical computations at various levels of theory including a one-electron pseudopotential model, several density functional theory (DFT) based methods, MP2 and coupled-cluster CCSD(T) calculations. The results suggest that at least four methanol molecules are needed to bind an excess electron on a hydrogen bonded methanol chain in a dipole bound state. Larger methanol clusters are able to form stronger interactions with an excess electron. The two simulated excess electron binding motifs in methanol clusters, interior and surface states, correlate well with distinct, experimentally found VDE tendencies with size. Interior states in a solvent cavity are stabilized significantly stronger than electron states on cluster surfaces. Although we find that all the examined quantum chemistry methods more or less overestimate the strength of the experimental excess electron stabilization, MP2, LC-BLYP, and BHandHLYP methods with diffuse basis sets provide a significantly better estimate of the VDE than traditional DFT methods (BLYP, B3LYP, X3LYP, PBE0). A comparison to the better performing many electron methods indicates that the examined one-electron pseudopotential can be reasonably used in simulations for systems of larger size.

  14. Electron dose rate and photon contamination in electron arc therapy

    International Nuclear Information System (INIS)

    Pla, M.; Podgorsak, E.B.; Pla, C.

    1989-01-01

    The electron dose rate at the depth of dose maximum dmax and the photon contamination are discussed as a function of several parameters of the rotational electron beam. A pseudoarc technique with an angular increment of 10 degrees and a constant number of monitor units per each stationary electron field was used in our experiments. The electron dose rate is defined as the electron dose at a given point in phantom divided by the number of monitor units given for any one stationary electron beam. For a given depth of isocenter di the electron dose rates at dmax are linearly dependent on the nominal field width w, while for a given w the dose rates are inversely proportional to di. The dose rates for rotational electron beams with different di are related through the inverse square law provided that the two beams have (di,w) combinations which give the same characteristic angle beta. The photon dose at the isocenter depends on the arc angle alpha, field width w, and isocenter depth di. For constant w and di the photon dose at isocenter is proportional to alpha, for constant alpha and w it is proportional to di, and for constant alpha and di it is inversely proportional to w. The w and di dependence implies that for the same alpha the photon dose at the isocenter is inversely proportional to the electron dose rate at dmax

  15. Power Electronics

    DEFF Research Database (Denmark)

    Iov, Florin; Ciobotaru, Mihai; Blaabjerg, Frede

    2008-01-01

    is to change the electrical power production sources from the conventional, fossil (and short term) based energy sources to renewable energy resources. The other is to use high efficient power electronics in power generation, power transmission/distribution and end-user application. This paper discuss the most...... emerging renewable energy sources, wind energy, which by means of power electronics are changing from being a minor energy source to be acting as an important power source in the energy system. Power electronics is the enabling technology and the presentation will cover the development in wind turbine...... technology from kW to MW, discuss which power electronic solutions are most feasible and used today....

  16. Electron Emission from Ultra-Large Area MOS Electron Emitters

    DEFF Research Database (Denmark)

    Thomsen, Lasse Bjørchmar; Nielsen, Gunver; Vendelbo, Søren Bastholm

    2009-01-01

    Ultralarge metal-oxide-semiconductor (MOS) devices with an active oxide area of 1 cm2 have been fabricated for use as electron emitters. The MOS structures consist of a Si substrate, a SiO2 tunnel barrier (~5 nm), a Ti wetting layer (3–10 Å), and a Au top layer (5–60 nm). Electron emission from...... layer is varied from 3 to 10 Å which changes the emission efficiency by more than one order of magnitude. The apparent mean free path of ~5 eV electrons in Au is found to be 52 Å. Deposition of Cs on the Au film increased the electron emission efficiency to 4.3% at 4 V by lowering the work function....... Electron emission under high pressures (up to 2 bars) of Ar was observed. ©2009 American Vacuum Society...

  17. Comparative analysis of the terms "electronic commerce" and "electronic business"

    OpenAIRE

    Kavaliauskienė, Virginija; Šarapovas, Tadas

    2002-01-01

    Establishing the terms that clearly and consistently describe growing and dynamic networked economy is a critical first step toward further analysis and evaluation of electronic commerce and electronic business processes. Electronic commerce is making an impact on the ways that purchasing activities are being conducted. Much of the early literature on this subject was very speculative. However, the growth of e-commerce has enabled more observations to be made of the use of electronic business...

  18. Electron-electron interaction and transfer ionization in fast ion-atom collisions

    International Nuclear Information System (INIS)

    Voitkiv, A B

    2008-01-01

    Recently it was pointed out that electron capture occurring in fast ion-atom collisions can proceed via a mechanism which earlier was not considered. In the present paper we study this mechanism in more detail. Similarly as in radiative capture, where the electron transfer occurs due to the interaction with the radiation field and proceeds via emission of a photon, within this mechanism the electron capture is caused by the interaction with another atomic electron leading mainly to the emission of the latter. In contrast to the electron-electron Thomas capture, this electron-electron (E-E) mechanism is basically a first-order one having similarities to the kinematic and radiative capture channels. It also possesses important differences with the latter two. Leading to transfer ionization, this first-order capture mechanism results in the electron emission mainly in the direction opposite to the motion of the projectile ion. The same, although less pronounced, feature is also characteristic for the momenta of the target recoil ions produced via this mechanism. It is also shown that the action of the E-E mechanism is clearly seen in recent experimental data on the transfer ionization in fast proton-helium collisions.

  19. Determination of electron temperature and electron density in ...

    African Journals Online (AJOL)

    It is seen that the electron temperature increases from 5.8 × 102 oK to 7.83 × 104 oK as the pd is reduced from 130mm Hg × mm to 60 mm Hg × mm for argon. The electron densities increases from 2.8 × 1011/cm3 to 3.2 × 1011 /cm3 for the same variation of pds. For air the electron temperature increases from 3.6 × 104 oK to ...

  20. Optimising electron microscopy experiment through electron optics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, Y. [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse France (France); Hitachi High-Technologies Corporation, 882, Ichige, Hitachinaka, Ibaraki 312-8504 (Japan); Gatel, C.; Snoeck, E. [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse France (France); Houdellier, F., E-mail: florent.houdellier@cemes.fr [CEMES-CNRS, 29 Rue Jeanne Marvig, 31055 Toulouse France (France)

    2017-04-15

    We developed a new type of electron trajectories simulation inside a complete model of a modern transmission electron microscope (TEM). Our model incorporates the precise and real design of each element constituting a TEM, i.e. the field emission (FE) cathode, the extraction optic and acceleration stages of a 300 kV cold field emission gun, the illumination lenses, the objective lens, the intermediate and projection lenses. Full trajectories can be computed using magnetically saturated or non-saturated round lenses, magnetic deflectors and even non-cylindrical symmetry elements like electrostatic biprism. This multi-scale model gathers nanometer size components (FE tip) with parts of meter length (illumination and projection systems). We demonstrate that non-trivial TEM experiments requiring specific and complex optical configurations can be simulated and optimized prior to any experiment using such model. We show that all the currents set in all optical elements of the simulated column can be implemented in the real column (I2TEM in CEMES) and used as starting alignment for the requested experiment. We argue that the combination of such complete electron trajectory simulations in the whole TEM column with automatic optimization of the microscope parameters for optimal experimental data (images, diffraction, spectra) allows drastically simplifying the implementation of complex experiments in TEM and will facilitate the development of advanced use of the electron microscope in the near future. - Highlights: • Using dedicated electron optics software, we calculate full electrons trajectories inside a modern transmission electron microscope. • We have determined how to deal with multi-scale electron optics elements like high voltage cold field emission source. • W • e have succeed to model both weak and strong magnetic lenses whether in saturated or unsaturated conditions as well as electrostatic biprism and magnetic deflectors. • We have applied this model

  1. Optimising electron microscopy experiment through electron optics simulation

    International Nuclear Information System (INIS)

    Kubo, Y.; Gatel, C.; Snoeck, E.; Houdellier, F.

    2017-01-01

    We developed a new type of electron trajectories simulation inside a complete model of a modern transmission electron microscope (TEM). Our model incorporates the precise and real design of each element constituting a TEM, i.e. the field emission (FE) cathode, the extraction optic and acceleration stages of a 300 kV cold field emission gun, the illumination lenses, the objective lens, the intermediate and projection lenses. Full trajectories can be computed using magnetically saturated or non-saturated round lenses, magnetic deflectors and even non-cylindrical symmetry elements like electrostatic biprism. This multi-scale model gathers nanometer size components (FE tip) with parts of meter length (illumination and projection systems). We demonstrate that non-trivial TEM experiments requiring specific and complex optical configurations can be simulated and optimized prior to any experiment using such model. We show that all the currents set in all optical elements of the simulated column can be implemented in the real column (I2TEM in CEMES) and used as starting alignment for the requested experiment. We argue that the combination of such complete electron trajectory simulations in the whole TEM column with automatic optimization of the microscope parameters for optimal experimental data (images, diffraction, spectra) allows drastically simplifying the implementation of complex experiments in TEM and will facilitate the development of advanced use of the electron microscope in the near future. - Highlights: • Using dedicated electron optics software, we calculate full electrons trajectories inside a modern transmission electron microscope. • We have determined how to deal with multi-scale electron optics elements like high voltage cold field emission source. • W • e have succeed to model both weak and strong magnetic lenses whether in saturated or unsaturated conditions as well as electrostatic biprism and magnetic deflectors. • We have applied this model

  2. Lead-Free Electronics: Impact for Space Electronics

    Science.gov (United States)

    Sampson, Michael J.

    2010-01-01

    Pb is used as a constituent in solder alloys used to connect and attach electronic parts to printed wiring boards (PWBs). Similar Pbbearing alloys are electroplated or hot dipped onto the terminations of electronic parts to protect the terminations and make them solderable. Changing to Pb-free solders and termination finishes has introduced significant technical challenges into the supply chain. Tin/lead (Sn/Pb) alloys have been the solders of choice for electronics for more than 50 years. Pb-free solder alloys are available but there is not a plug-in replacement for 60/40 or 63/37 (Sn/Pb) alloys, which have been the industry workhorses.

  3. Observation of electron plasma waves in plasma of two-temperature electrons

    International Nuclear Information System (INIS)

    Ikezawa, Shunjiro; Nakamura, Yoshiharu.

    1981-01-01

    Propagation of electron plasma waves in a large and unmagnetized plasma containing two Maxwellian distributions of electrons is studied experimentally. Two kinds of plasma sources which supply electrons of different temperature are used. The temperature ratio is about 3 and the density ratio of hot to cool electrons is varied from 0 to 0.5. A small contamination of hot electrons enhances the Landau damping of the principal mode known as the Bohm-Gross mode. When the density of hot electrons is larger than about 0.2, two modes are observed. The results agree with theoretical dispersion relations when excitation efficiencies of the modes are considered. (author)

  4. Electron energy and electron trajectories in an inverse free-electron laser accelerator based on a novel electrostatic wiggler

    Science.gov (United States)

    Nikrah, M.; Jafari, S.

    2016-06-01

    We expand here a theory of a high-gradient laser-excited electron accelerator based on an inverse free-electron laser (inverse-FEL), but with innovations in the structure and design. The electrostatic wiggler used in our scheme, namely termed the Paul wiggler, is generated by segmented cylindrical electrodes with applied oscillatory voltages {{V}\\text{osc}}(t) over {{90}\\circ} segments. The inverse-FEL interaction can be described by the equations that govern the electron motion in the combined fields of both the laser pulse and Paul wiggler field. A numerical study of electron energy and electron trajectories has been made using the fourth-order Runge-Kutta method. The results indicate that the electron attains a considerable energy at short distances in this device. It is found that if the electron has got sufficient suitable wiggler amplitude intensities, it can not only gain higher energy in longer distances, but also can retain it even after the passing of the laser pulse. In addition, the results reveal that the electron energy gains different peaks for different initial axial velocities, so that a suitable small initial axial velocity of e-beam produces substantially high energy gain. With regard to the transverse confinement of the electron beam in a Paul wiggler, there is no applied axial guide magnetic field in this device.

  5. Plasmaspheric electron content

    International Nuclear Information System (INIS)

    Hartmann, G.K.

    1978-01-01

    Measurements of the plasmaspheric electron content are reviewed with particular reference to the ATS-6 radio beacon experiment. From the review, it appears likely that measurement of the plasmaspheric electron content is the only one capable of monitoring electron fluxes continuously between L 1 and L 2. Some recent important results deduced from plasmaspheric electron content measurements are discussed

  6. A 20 keV electron gun system for the electron irradiation experiments

    International Nuclear Information System (INIS)

    Mahapatra, S.K.; Dhole, S.D.; Bhoraskar, V.N.

    2005-01-01

    An electron gun consisting of cathode, focusing electrode, control electrode and anode has been designed and fabricated for the electron irradiation experiments. This electron gun can provide electrons of any energy over the range 1-20 keV, with current upto 50 μA. This electron gun and a Faraday cup are mounted in the cylindrical chamber. The samples are fixed on the Faraday cup and irradiated with electrons at a pressure ∼10 -7 mbar. The special features of this electron gun system are that, at any electron energy above 1 keV, the electron beam diameter can be varied from 5 to 120 mm on the Faraday cup mounted at a distance of 200 mm from the anode in the chamber. The variation in the electron current over the beam spot of 120 mm diameter is less than 15% and the beam current stability is better than 5%. This system is being used for studying the irradiation effects of 1-20 keV energy electrons on the space quality materials in which the irradiation time may vary from a few tens of seconds to hours

  7. A 20 keV electron gun system for the electron irradiation experiments

    Energy Technology Data Exchange (ETDEWEB)

    Mahapatra, S.K. [Department of Physics, University of Pune, Pune 411007 (India); Dhole, S.D. [Department of Physics, University of Pune, Pune 411007 (India); Bhoraskar, V.N. [Department of Physics, University of Pune, Pune 411007 (India)]. E-mail: vnb@physics.unipune.ernet.in

    2005-01-01

    An electron gun consisting of cathode, focusing electrode, control electrode and anode has been designed and fabricated for the electron irradiation experiments. This electron gun can provide electrons of any energy over the range 1-20 keV, with current upto 50 {mu}A. This electron gun and a Faraday cup are mounted in the cylindrical chamber. The samples are fixed on the Faraday cup and irradiated with electrons at a pressure {approx}10{sup -7} mbar. The special features of this electron gun system are that, at any electron energy above 1 keV, the electron beam diameter can be varied from 5 to 120 mm on the Faraday cup mounted at a distance of 200 mm from the anode in the chamber. The variation in the electron current over the beam spot of 120 mm diameter is less than 15% and the beam current stability is better than 5%. This system is being used for studying the irradiation effects of 1-20 keV energy electrons on the space quality materials in which the irradiation time may vary from a few tens of seconds to hours.

  8. Effect of electron beam on the properties of electron-acoustic rogue waves

    Science.gov (United States)

    El-Shewy, E. K.; Elwakil, S. A.; El-Hanbaly, A. M.; Kassem, A. I.

    2015-04-01

    The properties of nonlinear electron-acoustic rogue waves have been investigated in an unmagnetized collisionless four-component plasma system consisting of a cold electron fluid, Maxwellian hot electrons, an electron beam and stationary ions. It is found that the basic set of fluid equations is reduced to a nonlinear Schrodinger equation. The dependence of rogue wave profiles and the associated electric field on the carrier wave number, normalized density of hot electron and electron beam, relative cold electron temperature and relative beam temperature are discussed. The results of the present investigation may be applicable in auroral zone plasma.

  9. Electron cooling and recombination experiments with an adiabatically expanded electron beam

    International Nuclear Information System (INIS)

    Pastuszka, S.; Heidelberg Univ.; Schramm, U.; Heidelberg Univ.; Grieser, M.; Heidelberg Univ.; Broude, C.; Heidelberg Univ.; Grimm, R.; Heidelberg Univ.; Habs, D.; Heidelberg Univ.; Kenntner, J.; Heidelberg Univ.; Miesner, H.J.; Heidelberg Univ.; Schuessler, T.; Heidelberg Univ.; Schwalm, D.; Heidelberg Univ.; Wolf, A.; Heidelberg Univ.

    1996-01-01

    Magnetically guided electron beams with transverse temperatures reduced with respect to the cathode temperature by a factor of more than 7 were realized in the electron cooling device of the heavy-ion storage ring TSR and the effect of the reduced transverse temperature in recombination and electron cooling experiments was studied. Measured dielectronic recombination resonances at low relative energy and spectra of laser-stimulated recombination indicate that transverse electron temperatures of about 17 meV have been obtained at cathode temperatures of about 110 meV. The temperature dependence of the spontaneous electron-ion recombination rate during electron cooling was investigated and found to follow the inverse square-root law expected from the theory of radiative recombination, although the measured absolute rates are higher than predicted. A new method based on analyzing the intensity of the fluorescence light emitted during simultaneous laser and electron cooling is used to measure the longitudinal electron cooling force in a range of relative velocities extending over two orders of magnitude (10 5 -10 7 cm/s). The results confirm the occurrence of 'magnetized electron cooling' also at the reduced transverse temperature and show that, compared to earlier measurements at the high transverse temperature, the cooling force increases by about a factor of 2; a considerably larger increase by a factor of ∼5 would be expected if 'magnetized electron cooling' would not exist. (orig.)

  10. Electronic structure of elements and compounds and electronic phases of solids

    International Nuclear Information System (INIS)

    Nadykto, B.A.

    2000-01-01

    The paper reviews technique and computed energies for various electronic states of many-electron multiply charged ions, molecular ions, and electronic phases of solids. The model used allows computation of the state energy for free many-electron multiply charged ions with relative accuracy ∼10 -4 suitable for analysis of spectroscopy data

  11. Three-dimensional nanofabrication by electron-beam-induced deposition using 200-keV electrons in scanning transmission electron microscope

    International Nuclear Information System (INIS)

    Liu, Z.Q.; Mitsuishi, K.; Furuya, K.

    2005-01-01

    Attempts were made to fabricate three-dimensional nanostructures on and out of a substrate by electron-beam-induced deposition in a 200-kV scanning transmission electron microscope. Structures with parallel wires over the substrate surface were difficult to fabricate due to the direct deposition of wires on both top and bottom surfaces of the substrate. Within the penetration depth of the incident electron beam, nanotweezers were fabricated by moving the electron beam beyond different substrate layers. Combining the deposition of self-supporting wires and self-standing tips, complicated three-dimensional doll-like, flag-like, and gate-like nanostructures that extend out of the substrate were successfully fabricated with one-step or multi-step scans of the electron beam. Effects of coarsening, nucleation, and distortion during electron-beam-induced deposition are discussed. (orig.)

  12. Secondary electron emission yield in the limit of low electron energy

    CERN Document Server

    Andronov, A.N.; Kaganovich, I.D.; Startsev, E.A.; Raitses, Y.; Demidov, V.I.

    2013-04-22

    Secondary electron emission (SEE) from solids plays an important role in many areas of science and technology.1 In recent years, there has been renewed interest in the experimental and theoretical studies of SEE. A recent study proposed that the reflectivity of very low energy electrons from solid surface approaches unity in the limit of zero electron energy2,3,4, If this was indeed the case, this effect would have profound implications on the formation of electron clouds in particle accelerators,2-4 plasma measurements with electrostatic Langmuir probes, and operation of Hall plasma thrusters for spacecraft propulsion5,6. It appears that, the proposed high electron reflectivity at low electron energies contradicts to numerous previous experimental studies of the secondary electron emission7. The goal of this note is to discuss possible causes of these contradictions.

  13. Electron spectroscopy

    International Nuclear Information System (INIS)

    Hegde, M.S.

    1979-01-01

    An introduction to the various techniques in electron spectroscopy is presented. These techniques include: (1) UV Photoelectron spectroscopy, (2) X-ray Photoelectron spectroscopy, (3) Auger electron spectroscopy, (4) Electron energy loss spectroscopy, (5) Penning ionization spectroscopy and (6) Ion neutralization spectroscopy. The radiations used in each technique, the basis of the technique and the special information obtained in structure determination in atoms and molecules by each technique are summarised. (A.K.)

  14. Perpendicular electron cyclotron emission from hot electrons in TMX-U

    International Nuclear Information System (INIS)

    James, R.A.; Ellis, R.F.; Lasnier, C.J.; Casper, T.A.; Celata, C.M.

    1984-01-01

    Perpendicular electron cyclotron emission (PECE) from the electron cyclotron resonant heating of hot electrons in TMX-U is measured at 30 to 40 and 50 to 75 GHz. This emission is optically thin and is measured at the midplane, f/sub ce/ approx. = 14 GHz, in either end cell. In the west end cell, the emission can be measured at different axial positions thus yielding the temporal history of the hot electron axial profile. These profiles are in excellent agreement with the axial diamagnetic signals. In addition, the PECE signal level correlates well with the diamagnetic signal over a wide range of hot electron densities. Preliminary results from theoretical modeling and comparisons with other diagnostics are also presented

  15. A ferroelectric electron gun in a free-electron maser experiment

    International Nuclear Information System (INIS)

    Einat, M.; Jerby, E.; Rosenman, G.

    2002-01-01

    An electron-gun based on a ferroelectric cathode is studied in a free-electron maser (FEM) experiment. In this gun, the electrons are separated from the cathode surface plasma, and are accelerated in two stages. The electron energy-spread is reduced sufficiently for an FEM operation in the microwave regime. A 14 keV, 1-2 A e-beam is obtained in a 0.1-2.1 μs pulse width. The pulse repetition frequency attains 3.1 MHz in ∼50% duty-cycle. This gun is implemented in an FEM oscillator experiment operating around 3 GHz. The paper presents experimental results and discusses the applicability of ferroelectric guns in free-electron laser devices

  16. A ferroelectric electron gun in a free-electron maser experiment

    CERN Document Server

    Einat, M; Rosenman, G

    2002-01-01

    An electron-gun based on a ferroelectric cathode is studied in a free-electron maser (FEM) experiment. In this gun, the electrons are separated from the cathode surface plasma, and are accelerated in two stages. The electron energy-spread is reduced sufficiently for an FEM operation in the microwave regime. A 14 keV, 1-2 A e-beam is obtained in a 0.1-2.1 mu s pulse width. The pulse repetition frequency attains 3.1 MHz in approx 50% duty-cycle. This gun is implemented in an FEM oscillator experiment operating around 3 GHz. The paper presents experimental results and discusses the applicability of ferroelectric guns in free-electron laser devices.

  17. The architecture of the chloroplast trnH-psbA non-coding region in angiosperms

    Czech Academy of Sciences Publication Activity Database

    Štorchová, Helena; Olson, M.S.

    2007-01-01

    Roč. 268, 1-4 (2007), s. 235-256 ISSN 0378-2697 R&D Projects: GA MŠk(CZ) LC06004 Grant - others:ESPSCor Visiting Scholar Research Grant(US) NSF DEB 0317115 Institutional research plan: CEZ:AV0Z50380511 Source of funding: V - iné verejné zdroje ; V - iné verejné zdroje Keywords : Chloroplast DNA * psbA-trnH intergenic region * Silene * deletions * insertions and inversions in stem-loop region * psbA 3´untranslated region * RNA secondary structure Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 1.492, year: 2007

  18. New Records To The Vascular Flora Of Kazakhstan (Central Asia

    Directory of Open Access Journals (Sweden)

    Ebel Aleksandr L.

    2015-12-01

    Full Text Available The paper presents distributional data for seven species new for the flora of Kazakhstan: Atriplex gardneri var. aptera (A. Nelson S. L. Welsh. & Crompton, Cardamine hirsuta L., Carduus acanthoides L., Galega orientalis Lam., Silene cserei Baumg., Didymophysa fedtschenkoana Regel and Acinos arvensis (Lam. Dandy. Didymophysa fedtschenkoana is a native element in the Kazakh flora; the other species should be treated as alien, expansively spreading or invasive in this part of Asia. A list of localities of the species in Kazakhstan and their habitat preferences are presented.

  19. Avaliação da suscetibilidade natural e do potencial à erosão laminar na Bacia Hidrográfica do Ribeirão do Boqueirão, município de Davinópolis (GO)

    OpenAIRE

    Rodrigues, Diego Emanoel

    2016-01-01

    As sociedades humanas ao longo do tempo desenvolveram e aumentaram a sua capacidade de reorganizar espacialmente os elementos do meio que as envolve. Dessa forma, a intervenção antrópica se tornou um dos agentes dinamizadores da paisagem, juntamente com os processos físicos e biológicos. Isso implica dizer que as atividades humanas influem e aceleram os processos de erosão. Especificamente, a erosão laminar é uma forma de manifestação da erosão hídrica que ocorre de forma silen...

  20. Paper electronics.

    Science.gov (United States)

    Tobjörk, Daniel; Österbacka, Ronald

    2011-05-03

    Paper is ubiquitous in everyday life and a truly low-cost substrate. The use of paper substrates could be extended even further, if electronic applications would be applied next to or below the printed graphics. However, applying electronics on paper is challenging. The paper surface is not only very rough compared to plastics, but is also porous. While this is detrimental for most electronic devices manufactured directly onto paper substrates, there are also approaches that are compatible with the rough and absorptive paper surface. In this review, recent advances and possibilities of these approaches are evaluated and the limitations of paper electronics are discussed. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Destabilization of the electron Bernstein modes by runaway electrons

    International Nuclear Information System (INIS)

    Hitchcock, D.A.; Mahajan, S.M.

    1982-01-01

    It is shown that the electromagnetic finite k/sub parallel/ electron Bernstein mode can be destabilized by the runaway electron distribution which results from the quasilinear action of the magnetized plasma oscillation. This mechanism is shown to yield growth rates of the order of 10 8 sec -1 and is suggested as a mechanism for the enchanced cyclotron harmonic emission in the presence of runaway electrons

  2. Surface-electronic-state effects in electron emission from the Be(0001) surface

    International Nuclear Information System (INIS)

    Archubi, C. D.; Gravielle, M. S.; Silkin, V. M.

    2011-01-01

    We study the electron emission produced by swift protons impinging grazingly on a Be(0001) surface. The process is described within a collisional formalism using the band-structure-based (BSB) approximation to represent the electron-surface interaction. The BSB model provides an accurate description of the electronic band structure of the solid and the surface-induced potential. Within this approach we derive both bulk and surface electronic states, with these latter characterized by a strong localization at the crystal surface. We found that such surface electronic states play an important role in double-differential energy- and angle-resolved electron emission probabilities, producing noticeable structures in the electron emission spectra.

  3. Surface-electronic-state effects in electron emission from the Be(0001) surface

    Energy Technology Data Exchange (ETDEWEB)

    Archubi, C. D. [Instituto de Astronomia y Fisica del Espacio, casilla de correo 67, sucursal 28, C1428EGA, Buenos Aires (Argentina); Gravielle, M. S. [Instituto de Astronomia y Fisica del Espacio, casilla de correo 67, sucursal 28, C1428EGA, Buenos Aires (Argentina); Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires (Argentina); Silkin, V. M. [Donostia International Physics Center, E-20018 San Sebastian (Spain); Departamento de Fisica de Materiales, Facultad de Ciencias Quimicas, Universidad del Pais Vasco, Apartado 1072, E-20080 San Sebastian (Spain); IKERBASQUE, Basque Foundation for Science, E-48011 Bilbao (Spain)

    2011-07-15

    We study the electron emission produced by swift protons impinging grazingly on a Be(0001) surface. The process is described within a collisional formalism using the band-structure-based (BSB) approximation to represent the electron-surface interaction. The BSB model provides an accurate description of the electronic band structure of the solid and the surface-induced potential. Within this approach we derive both bulk and surface electronic states, with these latter characterized by a strong localization at the crystal surface. We found that such surface electronic states play an important role in double-differential energy- and angle-resolved electron emission probabilities, producing noticeable structures in the electron emission spectra.

  4. Simulation of the electron acoustic instability for a finite-size electron beam system

    International Nuclear Information System (INIS)

    Lin, C.S.; Winske, D.

    1987-01-01

    Satellite observations at midlatitudes (≅20,000 km) near the earth's dayside polar cusp boundary layer indicate that the upward electron beams have a narrow latitudinal width up to 0.1 0 . In the cusp boundary layer where the electron population consists of a finite-size electron beam in a background of uniform cold and hot electrons, the electron acoustic mode is unstable inside the electron beam but damped outside the electron beam. Simulations of the electron acoustic instability for a finite-size beam system are carried out with a particle-in-cell code to investigate the heating phenomena associated with the instability and the width of the heating region. The simulations show that the finite-size electron beam radiates electrostatic electron acoustic waves. The decay length of the electron acoustic waves outside the beam in the simulation agrees with the spatial decay length derived from the linear dispersion equation

  5. Arbitrary amplitude slow electron-acoustic solitons in three-electron temperature space plasmas

    International Nuclear Information System (INIS)

    Mbuli, L. N.; Maharaj, S. K.; Bharuthram, R.; Singh, S. V.; Lakhina, G. S.

    2015-01-01

    We examine the characteristics of large amplitude slow electron-acoustic solitons supported in a four-component unmagnetised plasma composed of cool, warm, hot electrons, and cool ions. The inertia and pressure for all the species in this plasma system are retained by assuming that they are adiabatic fluids. Our findings reveal that both positive and negative potential slow electron-acoustic solitons are supported in the four-component plasma system. The polarity switch of the slow electron-acoustic solitons is determined by the number densities of the cool and warm electrons. Negative potential solitons, which are limited by the cool and warm electron number densities becoming unreal and the occurrence of negative potential double layers, are found for low values of the cool electron density, while the positive potential solitons occurring for large values of the cool electron density are only limited by positive potential double layers. Both the lower and upper Mach numbers for the slow electron-acoustic solitons are computed and discussed

  6. Electron cloud dynamics in the Cornell Electron Storage Ring Test Accelerator wiggler

    Directory of Open Access Journals (Sweden)

    C. M. Celata

    2011-04-01

    Full Text Available The interference of stray electrons (also called “electron clouds” with accelerator beams is important in modern intense-beam accelerators, especially those with beams of positive charge. In magnetic wigglers, used, for instance, for transverse emittance damping, the intense synchrotron radiation produced by the beam can generate an electron cloud of relatively high density. In this paper the complicated dynamics of electron clouds in wigglers is examined using the example of a wiggler in the Cornell Electron Storage Ring Test Accelerator experiment at the Cornell Electron Storage Ring. Three-dimensional particle-in-cell simulations with the WARP-POSINST computer code show different density and dynamics for the electron cloud at locations near the maxima of the vertical wiggler field when compared to locations near the minima. Dynamics in these regions, the electron cloud distribution vs longitudinal position, and the beam coherent tune shift caused by the wiggler electron cloud will be discussed.

  7. Arbitrary amplitude fast electron-acoustic solitons in three-electron component space plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Mbuli, L. N.; Maharaj, S. K. [South African National Space Agency (SANSA) Space Science, P.O. Box 32, Hermanus 7200, Republic of South Africa (South Africa); Department of Physics, University of the Western Cape (UWC), Robert Sobukwe Road, Bellville 7535, Republic of South Africa (South Africa); Bharuthram, R. [Department of Physics, University of the Western Cape (UWC), Robert Sobukwe Road, Bellville 7535, Republic of South Africa (South Africa); Singh, S. V.; Lakhina, G. S. [Indian Institute of Geomagnetism, New Panvel (West), Navi Mumbai 410218 (India); Department of Physics, University of the Western Cape (UWC), Robert Sobukwe Road, Bellville 7535, Republic of South Africa (South Africa)

    2016-06-15

    We examine the characteristics of fast electron-acoustic solitons in a four-component unmagnetised plasma model consisting of cool, warm, and hot electrons, and cool ions. We retain the inertia and pressure for all the plasma species by assuming adiabatic fluid behaviour for all the species. By using the Sagdeev pseudo-potential technique, the allowable Mach number ranges for fast electron-acoustic solitary waves are explored and discussed. It is found that the cool and warm electron number densities determine the polarity switch of the fast electron-acoustic solitons which are limited by either the occurrence of fast electron-acoustic double layers or warm and hot electron number density becoming unreal. For the first time in the study of solitons, we report on the coexistence of fast electron-acoustic solitons, in addition to the regular fast electron-acoustic solitons and double layers in our multi-species plasma model. Our results are applied to the generation of broadband electrostatic noise in the dayside auroral region.

  8. Electronic Market and Business: Cyberspace vs. Electronic Environment

    Directory of Open Access Journals (Sweden)

    Deniss Ščeulovs

    2013-12-01

    Full Text Available The authors of the article analyze the concept "electronic environment". Having studied a range of academic literature sources and other sources, the authors of the article have drawn a conclusion that the academic writings do not provide a definition of "electronic environment". Furthermore, the various opinions among specialists regarding this concept often differ. Meanwhile, there are several explanations of the term "cyberspace" overlapping the concept of "electronic environment", and these terms are often believed to be synonyms. To understand what the term "electronic environment" means and to properly and correctly employ this concept in entrepreneurship, the authors have performed a lexicographic analysis of this concept by comparing reciprocal concepts. As a result of the research, the authors propose their view on what, in their opinion, "electronic environment" is and what its connection to the concept "cyberspace" is. The topicality of the article lies in the fact that often entrepreneurs and specialists of public and other institutions, when using these terms, imply completely different concepts. It can lead to misunderstanding and misinterpreting the information, as well as to encumbering the understanding of tasks, problems, etc.

  9. Practical XHV electron gun

    International Nuclear Information System (INIS)

    Urata, Tomohiro; Ishikawa, Tsuyoshi; Cho, Boklae; Oshima, Chuhei

    2008-01-01

    We have developed practical XHV chambers of a electron gun, of which the operating pressures are 1x10 -9 Pa in a stainless-steel one and 4x10 -9 Pa in a permalloy one. By mounting a noble single-atom electron source with high brightness and high spatial coherence on the electron gun including electron optics, we demonstrated highly collimated electron-beam emission: ∼80% of the total emission current entered the electron optics. This ratio was two or three orders of magnitude higher than those of the conventional electron sources. In XHV, in addition, we confirmed stable electron emission up to 20 nA, which results in the specimen current high enough for scanning electron microscopes. (author)

  10. Two-Electron Transfer Pathways.

    Science.gov (United States)

    Lin, Jiaxing; Balamurugan, D; Zhang, Peng; Skourtis, Spiros S; Beratan, David N

    2015-06-18

    The frontiers of electron-transfer chemistry demand that we develop theoretical frameworks to describe the delivery of multiple electrons, atoms, and ions in molecular systems. When electrons move over long distances through high barriers, where the probability for thermal population of oxidized or reduced bridge-localized states is very small, the electrons will tunnel from the donor (D) to acceptor (A), facilitated by bridge-mediated superexchange interactions. If the stable donor and acceptor redox states on D and A differ by two electrons, it is possible that the electrons will propagate coherently from D to A. While structure-function relations for single-electron superexchange in molecules are well established, strategies to manipulate the coherent flow of multiple electrons are largely unknown. In contrast to one-electron superexchange, two-electron superexchange involves both one- and two-electron virtual intermediate states, the number of virtual intermediates increases very rapidly with system size, and multiple classes of pathways interfere with one another. In the study described here, we developed simple superexchange models for two-electron transfer. We explored how the bridge structure and energetics influence multielectron superexchange, and we compared two-electron superexchange interactions to single-electron superexchange. Multielectron superexchange introduces interference between singly and doubly oxidized (or reduced) bridge virtual states, so that even simple linear donor-bridge-acceptor systems have pathway topologies that resemble those seen for one-electron superexchange through bridges with multiple parallel pathways. The simple model systems studied here exhibit a richness that is amenable to experimental exploration by manipulating the multiple pathways, pathway crosstalk, and changes in the number of donor and acceptor species. The features that emerge from these studies may assist in developing new strategies to deliver multiple

  11. Electron-Electron and Electron-Phonon interactions effects on the tunnel electronic spectrum of PbS quantum dots

    Science.gov (United States)

    Wang, Hongyue; Lhuillier, Emmanuel; Yu, Qian; Mottaghizadeh, Alireza; Ulysse, Christian; Zimmers, Alexandre; Dubertret, Benoit; Aubin, Herve

    2015-03-01

    We present a tunnel spectroscopy study of the electronic spectrum of single PbS Quantum Dots (QDs) trapped between nanometer-spaced electrodes, measured at low temperature T=5 K. The carrier filling of the QD can be controlled either by the drain voltage in the shell filling regime or by a gate voltage. In the empty QD, the tunnel spectrum presents the expected signature of the 8x degenerated excited levels. In the drain controlled shell filling regime, the levels degeneracies are lifted by the global electrostatic Coulomb energy of the QD; in the gate controlled shell filling regime, the levels degeneracies are lifted by the intra-Coulomb interactions. In the charged quantum dot, electron-phonons interactions lead to the apparition of Franck-Condon side bands on the single excited levels and possibly Franck Condon blockade at low energy. The sharpening of excited levels at higher gate voltage suggests that the magnitude of electron-phonon interactions is decreased upon increasing the electron filling in the quantum dot. This work was supported by the French ANR Grants 10-BLAN-0409-01, 09-BLAN-0388-01, by the Region Ile-de-France in the framework of DIM Nano-K and by China Scholarship Council.

  12. Electron emitting filaments for electron discharge devices

    International Nuclear Information System (INIS)

    Leung, K.N.; Pincosy, P.A.; Ehlers, K.W.

    1988-01-01

    This patent describes an electron emitting device for use in an electron discharge system. It comprises: a filament having a pair of terminal ends, electrical supply means for supplying electrical power to the terminal ends of the filament for directly heating the filament by the passage of an electrical current along the filament between the terminal ends, the filament being substantially tapered in cross section continuously in one direction from one of its pair of terminal ends to another of its pair of terminal ends to achieve uniform heating of the filament along the length thereof by compensating for the nonuniform current along the filament due to the emission of electrons therefrom

  13. Electron irradiation-induced destruction of carbon nanotubes in electron microscopes

    International Nuclear Information System (INIS)

    Molhave, Kristian; Gudnason, Sven Bjarke; Pedersen, Anders Tegtmeier; Clausen, Casper Hyttel; Horsewell, Andy; Boggild, Peter

    2007-01-01

    Observations of carbon nanotubes under exposure to electron beam irradiation in standard transmission electron microscope (TEM) and scanning electron microscope (SEM) systems show that such treatment in some cases can cause severe damage of the nanotube structure, even at electron energies far below the approximate 100 keV threshold for knock-on damage displacing carbon atoms in the graphene structure. We find that the damage we observe in one TEM can be avoided by use of a cold finger. This and the morphology of the damage imply that water vapour, which is present as a background gas in many vacuum chambers, can damage the nanotube structure through electron beam-induced chemical reactions. Though, the dependence on the background gas makes these observations specific for the presently used systems, the results demonstrate the importance of careful assessment of the level of subtle structural damage that the individual electron microscope system can do to nanostructures during standard use

  14. Electron-attachment processes

    International Nuclear Information System (INIS)

    Christophorou, L.G.; McCorkle, D.L.; Christodoulides, A.A.

    1982-01-01

    Topics covered include: (1) modes of production of negative ions, (2) techniques for the study of electron attachment processes, (3) dissociative electron attachment to ground-state molecules, (4) dissociative electron attachment to hot molecules (effects of temperature on dissociative electron attachment), (5) molecular parent negative ions, and (6) negative ions formed by ion-pair processes and by collisions of molecules with ground state and Rydberg atoms

  15. Acceleration of electrons using an inverse free electron laser auto- accelerator

    International Nuclear Information System (INIS)

    Wernick, I.K.; Marshall, T.C.

    1992-07-01

    We present data from our study of a device known as the inverse free electron laser. First, numerical simulations were performed to optimize the design parameters for an experiment that accelerates electrons in the presence of an undulator by stimulated absorption of radiation. The Columbia free electron laser (FEL) was configured as an auto-accelerator (IFELA) system; high power (MW's) FEL radiation at ∼1.65 mm is developed along the first section of an undulator inside a quasi-optical resonator. The electron beam then traverses a second section of undulator where a fraction of the electrons is accelerated by stimulated absorption of the 1.65 mm wavelength power developed in the first undulator section. The second undulator section has very low gain and does not generate power on its own. We have found that as much as 60% of the power generated in the first section can be absorbed in the second section, providing that the initial electron energy is chosen correctly with respect to the parameters chosen for the first and second undulators. An electron momentum spectrometer is used to monitor the distribution of electron energies as the electrons exit the IFELA. We have found; using our experimental parameters, that roughly 10% of the electrons are accelerated to energies as high as 1100 keV, in accordance with predictions from the numerical model. The appearance of high energy electrons is correlated with the abrupt absorption of millimeter power. The autoaccelerator configuration is used because there is no intense source of coherent power at the 1.65 mm design wavelength other than the FEL

  16. Advanced Electronics

    Science.gov (United States)

    2017-07-21

    AFRL-RV-PS- AFRL-RV-PS- TR-2017-0114 TR-2017-0114 ADVANCED ELECTRONICS Ashwani Sharma 21 Jul 2017 Interim Report APPROVED FOR PUBLIC RELEASE...NUMBER Advanced Electronics 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 62601F 6. AUTHOR(S) 5d. PROJECT NUMBER 4846 Ashwani Sharma 5e. TASK NUMBER...Approved for public release; distribution is unlimited. (RDMX-17-14919 dtd 20 Mar 2018) 13. SUPPLEMENTARY NOTES 14. ABSTRACT The Space Electronics

  17. The Downshift of Electron Plasma Oscillations in the Electron Foreshock Region.

    Science.gov (United States)

    1984-10-10

    Ii D-Ai50 52 THE DOWNSHIFT OF ELECTRON PLASMA OSCILLATIONS IN THE i/1. ELECTRON FORESHOCK R.. (U) I0MM UNIV 10MM CITY DEPT OF PHYSICS AND ASTRONOMY 5...OSCILLATIONS 0 IN THE ELECTRON FORESHOCK REGION In by S. A. Fuselierl, D. A. Gurnett 1 , Ace NTI 0. and R. J. Fitzenreiter 2 DTI I ,3WERSflY o. 06UNDED ISAI...geleasel Ditibto Unlimited 02 1 16 U. of Iowa 84-21 THE DOWNSHIFT OF ELECTRON PLASMA OSCILLATIONSJ / IN THE ELECTRON FORESHOCK REGION t - by Z I S. A

  18. Electronics engineer's reference book

    CERN Document Server

    Mazda, F F

    1989-01-01

    Electronics Engineer's Reference Book, Sixth Edition is a five-part book that begins with a synopsis of mathematical and electrical techniques used in the analysis of electronic systems. Part II covers physical phenomena, such as electricity, light, and radiation, often met with in electronic systems. Part III contains chapters on basic electronic components and materials, the building blocks of any electronic design. Part IV highlights electronic circuit design and instrumentation. The last part shows the application areas of electronics such as radar and computers.

  19. Angular distribution of scattered electron and medium energy electron spectroscopy for metals

    International Nuclear Information System (INIS)

    Oguri, Takeo; Ishioka, Hisamichi; Fukuda, Hisashi; Irako, Mitsuhiro

    1986-01-01

    The angular distribution (AD) of scattered electrons produced by medium energy incident electrons (E P = 50 ∼ 300 eV) from polycrystalline Ti, Fe, Ni, Cu and Au were obtained by the angle-resolved medium energy electron spectrometer. The AD of the energy loss peaks are similar figures to AD of the elastically reflected electron peaks. Therefore, the exchanged electrons produced by the knock-on collision between the incident electrons and those of metals without momentum transfer are observed as the energy loss spectra (ELS). This interpretation differs from the inconsequent interpretation by the dielectric theory or the interband transition. The information depth and penetration length are obtained from AD of the Auger electron peaks. The contribution of the surface to spectra is 3 % at the maximum for E P = 50 eV. The true secondary peaks representing the secondary electron emission spectroscopy (SES) are caused by the emissions of the energetic electrons (kT e ≥ 4 eV), and SES is the inversion of ELS. The established fundamental view is that the medium energy electron spectra represent the total bulk density of states. (author)

  20. Wigner-like crystallization of Anderson-localized electron systems with low electron densities

    International Nuclear Information System (INIS)

    Slutskin, A.A.; Kovtun, H.A.; Pepper, M.

    2002-01-01

    We consider an electron system under conditions of strong Anderson localization, taking into account interelectron long-range Coulomb repulsion. We establish that at sufficiently low electron densities and sufficiently low temperatures the Coulomb electron interaction brings about ordering of the Anderson-localized electrons into a structure that is close to an ideal (Wigner) crystal lattice, provided the dimension of the system is > 1. This Anderson-Wigner glass (AWG) is a new macroscopic electron state that, on the one hand, is beyond the conventional Fermi glass concept, and on the other hand, qualitatively differs from the known 'plain' Wigner glass (inherent in self-localized electron systems) in that the random slight electron displacements from the ideal crystal sites essentially depend on the electron density. With increasing electron density the AWG is found to turn into the plain Wigner glass or Fermi glass, depending on the width of the random spread of the electron levels. It is shown that the residual disorder of the AWG is characterized by a multi-valley ground-state degeneracy akin to that in a spin glass. Some general features of the AWG are discussed, and a new conduction mechanism of a creep type is predicted

  1. 3D Printed structural electronics: embedding and connecting electronic components into freeform electronic devices

    NARCIS (Netherlands)

    Maalderink, H.H.H.; Bruning, F.B.J.; Schipper, M.M.R. de; Werff, J.J.J. van der; Germs, W.W.C.; Remmers, J.J.C.; Meinders, E.R.

    2018-01-01

    The need for personalised and smart products drives the development of structural electronics with mass-customisation capability. A number of challenges need to be overcome in order to address the potential of complete free form manufacturing of electronic devices. One key challenge is the

  2. 3D Printed structural electronics : embedding and connecting electronic components into freeform electronic devices

    NARCIS (Netherlands)

    Maalderink, H.H.; Bruning, F.B.J.; de Schipper, M.R.; van der Werff, J.J.; Germs, W.C.; Remmers, J.J.C.; Meinders, E.R.

    2018-01-01

    The need for personalised and smart products drives the development of structural electronics with mass-customisation capability. A number of challenges need to be overcome in order to address the potential of complete free form manufacturing of electronic devices. One key challenge is the

  3. 27 CFR 73.32 - May I electronically sign forms I submit electronically to TTB?

    Science.gov (United States)

    2010-04-01

    ... AND TOBACCO TAX AND TRADE BUREAU, DEPARTMENT OF THE TREASURY (CONTINUED) PROCEDURES AND PRACTICES ELECTRONIC SIGNATURES; ELECTRONIC SUBMISSION OF FORMS Electronic Filing of Documents with TTB § 73.32 May I electronically sign forms I submit electronically to TTB? You may electronically sign the electronic form you...

  4. Electron Bifurcation: Thermodynamics and Kinetics of Two-Electron Brokering in Biological Redox Chemistry.

    Science.gov (United States)

    Zhang, Peng; Yuly, Jonathon L; Lubner, Carolyn E; Mulder, David W; King, Paul W; Peters, John W; Beratan, David N

    2017-09-19

    How can proteins drive two electrons from a redox active donor onto two acceptors at very different potentials and distances? And how can this transaction be conducted without dissipating very much energy or violating the laws of thermodynamics? Nature appears to have addressed these challenges by coupling thermodynamically uphill and downhill electron transfer reactions, using two-electron donor cofactors that have very different potentials for the removal of the first and second electron. Although electron bifurcation is carried out with near perfection from the standpoint of energy conservation and electron delivery yields, it is a biological energy transduction paradigm that has only come into focus recently. This Account provides an exegesis of the biophysical principles that underpin electron bifurcation. Remarkably, bifurcating electron transfer (ET) proteins typically send one electron uphill and one electron downhill by similar energies, such that the overall reaction is spontaneous, but not profligate. Electron bifurcation in the NADH-dependent reduced ferredoxin: NADP + oxidoreductase I (Nfn) is explored in detail here. Recent experimental progress in understanding the structure and function of Nfn allows us to dissect its workings in the framework of modern ET theory. The first electron that leaves the two-electron donor flavin (L-FAD) executes a positive free energy "uphill" reaction, and the departure of this electron switches on a second thermodynamically spontaneous ET reaction from the flavin along a second pathway that moves electrons in the opposite direction and at a very different potential. The singly reduced ET products formed from the bifurcating flavin are more than two nanometers distant from each other. In Nfn, the second electron to leave the flavin is much more reducing than the first: the potentials are said to be "crossed." The eventually reduced cofactors, NADH and ferredoxin in the case of Nfn, perform crucial downstream redox

  5. Inter-populations genetic and morphological diversity in three Silene ...

    African Journals Online (AJOL)

    enoho

    2012-03-30

    Mar 30, 2012 ... 2Biology Department, School of Basic Sciences, Science and Research Branch, Islamic Azad University (SRBIAU), ... other populations in both morphological and molecular features. ... species with world-wide distribution.

  6. Electronic Elections

    DEFF Research Database (Denmark)

    Schürmann, Carsten

    2009-01-01

    Electronic voting technology is a two edged sword. It comes with many risks but brings also many benefits. Instead of flat out rejecting the technology as uncontrollably dangerous, we advocate in this paper a different technological angle that renders electronic elections trustworthy beyond...... the usual levels of doubt. We exploit the trust that voters currently have into the democratic process and model our techniques around that observation accordingly. In particular, we propose a technique of trace emitting computations to record the individual steps of an electronic voting machine...... for a posteriori validation on an acceptably small trusted computing base. Our technology enables us to prove that an electronic elections preserves the voter’s intent, assuming that the voting machine and the trace verifier are independent....

  7. Low-dose electron energy-loss spectroscopy using electron counting direct detectors.

    Science.gov (United States)

    Maigné, Alan; Wolf, Matthias

    2018-03-01

    Since the development of parallel electron energy loss spectroscopy (EELS), charge-coupled devices (CCDs) have been the default detectors for EELS. With the recent development of electron-counting direct-detection cameras, micrographs can be acquired under very low electron doses at significantly improved signal-to-noise ratio. In spectroscopy, in particular in combination with a monochromator, the signal can be extremely weak and the detection limit is principally defined by noise introduced by the detector. Here we report the use of an electron-counting direct-detection camera for EEL spectroscopy. We studied the oxygen K edge of amorphous ice and obtained a signal noise ratio up to 10 times higher than with a conventional CCD.We report the application of electron counting to record time-resolved EEL spectra of a biological protein embedded in amorphous ice, revealing chemical changes observed in situ while exposed by the electron beam. A change in the fine structure of nitrogen K and the carbon K edges were recorded during irradiation. A concentration of 3 at% nitrogen was detected with a total electron dose of only 1.7 e-/Å2, extending the boundaries of EELS signal detection at low electron doses.

  8. How do electron localization functions describe π-electron delocalization?

    Science.gov (United States)

    Steinmann, Stephan N; Mo, Yirong; Corminboeuf, Clemence

    2011-12-14

    Scalar fields provide an intuitive picture of chemical bonding. In particular, the electron localization function (ELF) has proven to be highly valuable in interpreting a broad range of bonding patterns. The discrimination between enhanced or reduced electron (de)localization within cyclic π-conjugated systems remains, however, challenging for ELF. In order to clearly distinguish between the local properties of ten highly and weakly π-(de)localized prototype systems, we compare the ELFs of both the canonical wave functions and electron-localized states (diabatic) with those of two closely related scalar fields: the electron localizability indicator (ELI-D) and the localized orbital locator (LOL). The simplest LOL function distinguishes enhanced from weak π-(de)localization in an insightful and reliable manner. LOL offers the finest contrast between annulenes with 4n/4n + 2 π electrons and their inorganic analogues as well as between hyperconjugated cyclopentadiene derivatives. LOL(π) also gives an appealing and intuitive picture of the π-bond. In contrast, the most popular ELF fails to capture subtle contrasting local electronic properties and suffers from the arbitrariness of the σ/π dissection. The orbital separation of the most recent ELI-D is clear-cut but the interpretations sometime less straightforward in the present context.

  9. Electron shuttles in biotechnology.

    Science.gov (United States)

    Watanabe, Kazuya; Manefield, Mike; Lee, Matthew; Kouzuma, Atsushi

    2009-12-01

    Electron-shuttling compounds (electron shuttles [ESs], or redox mediators) are essential components in intracellular electron transfer, while microbes also utilize self-produced and naturally present ESs for extracellular electron transfer. These compounds assist in microbial energy metabolism by facilitating electron transfer between microbes, from electron-donating substances to microbes, and/or from microbes to electron-accepting substances. Artificially supplemented ESs can create new routes of electron flow in the microbial energy metabolism, thereby opening up new possibilities for the application of microbes to biotechnology processes. Typical examples of such processes include halogenated-organics bioremediation, azo-dye decolorization, and microbial fuel cells. Herein we suggest that ESs can be applied widely to create new microbial biotechnology processes.

  10. Evaluation of LLNL's Nuclear Accident Dosimeters at the CALIBAN Reactor September 2010

    International Nuclear Information System (INIS)

    Hickman, D.P.; Wysong, A.R.; Heinrichs, D.P.; Wong, C.T.; Merritt, M.J.; Topper, J.D.; Gressmann, F.A.; Madden, D.J.

    2011-01-01

    The Lawrence Livermore National Laboratory uses neutron activation elements in a Panasonic TLD holder as a personnel nuclear accident dosimeter (PNAD). The LLNL PNAD has periodically been tested using a Cf-252 neutron source, however until 2009, it was more than 25 years since the PNAD has been tested against a source of neutrons that arise from a reactor generated neutron spectrum that simulates a criticality. In October 2009, LLNL participated in an intercomparison of nuclear accident dosimeters at the CEA Valduc Silene reactor (Hickman, et.al. 2010). In September 2010, LLNL participated in a second intercomparison of nuclear accident dosimeters at CEA Valduc. The reactor generated neutron irradiations for the 2010 exercise were performed at the Caliban reactor. The Caliban results are described in this report. The procedure for measuring the nuclear accident dosimeters in the event of an accident has a solid foundation based on many experimental results and comparisons. The entire process, from receiving the activated NADs to collecting and storing them after counting was executed successfully in a field based operation. Under normal conditions at LLNL, detectors are ready and available 24/7 to perform the necessary measurement of nuclear accident components. Likewise LLNL maintains processing laboratories that are separated from the areas where measurements occur, but contained within the same facility for easy movement from processing area to measurement area. In the event of a loss of LLNL permanent facilities, the Caliban and previous Silene exercises have demonstrated that LLNL can establish field operations that will very good nuclear accident dosimetry results. There are still several aspects of LLNL's nuclear accident dosimetry program that have not been tested or confirmed. For instance, LLNL's method for using of biological samples (blood and hair) has not been verified since the method was first developed in the 1980's. Because LLNL and the other DOE

  11. Treatment of foods with 'soft-electrons' (low-energy electrons)

    Energy Technology Data Exchange (ETDEWEB)

    Hayashi, Toru [Japan International Research Center for Agricultural Sciences (JIRCAS), Tsukuba, Ibaraki (Japan); Todoriki, Setsuko [National Food Research Institute (NFRI), Tsukuba, Ibaraki (Japan)

    2003-02-01

    Electrons with energies of 300 keV or lower were defined as soft-electrons'. Soft-electrons can eradicate microorganisms residing on the surface of grains, pulses, spices, dehydrated vegetables, tea leaves and seeds, and reduce their microbial loads to levels lower than 10 CFU/g with little quality deterioration. Soft-electrons can inactivate insect pests infesting grains and pulses and inhibit sprouting of potatoes. (author)

  12. Electron beam collimation with a photon MLC for standard electron treatments

    Science.gov (United States)

    Mueller, S.; Fix, M. K.; Henzen, D.; Frei, D.; Frauchiger, D.; Loessl, K.; Stampanoni, M. F. M.; Manser, P.

    2018-01-01

    Standard electron treatments are currently still performed using standard or molded patient-specific cut-outs placed in the electron applicator. Replacing cut-outs and electron applicators with a photon multileaf collimator (pMLC) for electron beam collimation would make standard electron treatments more efficient and would facilitate advanced treatment techniques like modulated electron radiotherapy (MERT) and mixed beam radiotherapy (MBRT). In this work, a multiple source Monte Carlo beam model for pMLC shaped electron beams commissioned at a source-to-surface distance (SSD) of 70 cm is extended for SSDs of up to 100 cm and validated for several Varian treatment units with field sizes typically used for standard electron treatments. Measurements and dose calculations agree generally within 3% of the maximal dose or 2 mm distance to agreement. To evaluate the dosimetric consequences of using pMLC collimated electron beams for standard electron treatments, pMLC-based and cut-out-based treatment plans are created for a left and a right breast boost, a sternum, a testis and a parotid gland case. The treatment plans consist of a single electron field, either alone (1E) or in combination with two 3D conformal tangential photon fields (1E2X). For each case, a pMLC plan with similar treatment plan quality in terms of dose homogeneity to the target and absolute mean dose values to the organs at risk (OARs) compared to a cut-out plan is found. The absolute mean dose to an OAR is slightly increased for pMLC-based compared to cut-out-based 1E plans if the OAR is located laterally close to the target with respect to beam direction, or if a 6 MeV electron beam is used at an extended SSD. In conclusion, treatment plans using cut-out collimation can be replaced by plans of similar treatment plan quality using pMLC collimation with accurately calculated dose distributions.

  13. Technical report of electronics shop characteristics of high speed electronics component, (1)

    International Nuclear Information System (INIS)

    Watanabe, Shin-ichi; Shiino, Kazuo.

    1975-01-01

    We must develop electronics circuits for high speed signals. The electronics components of the circuits make use of the special components. This report treats a pulse response of the electronics components (i.e. coaxial cable, connector, resistor, capacitor, diode, transistor) for high speed electronics. The results of this report was already applied constructions of high speed electronics circuits and experimental equipments of the High Energy Physics Division. (auth.)

  14. Fully printable, strain-engineered electronic wrap for customizable soft electronics.

    Science.gov (United States)

    Byun, Junghwan; Lee, Byeongmoon; Oh, Eunho; Kim, Hyunjong; Kim, Sangwoo; Lee, Seunghwan; Hong, Yongtaek

    2017-03-24

    Rapid growth of stretchable electronics stimulates broad uses in multidisciplinary fields as well as industrial applications. However, existing technologies are unsuitable for implementing versatile applications involving adaptable system design and functions in a cost/time-effective way because of vacuum-conditioned, lithographically-predefined processes. Here, we present a methodology for a fully printable, strain-engineered electronic wrap as a universal strategy which makes it more feasible to implement various stretchable electronic systems with customizable layouts and functions. The key aspects involve inkjet-printed rigid island (PRI)-based stretchable platform technology and corresponding printing-based automated electronic functionalization methodology, the combination of which provides fully printed, customized layouts of stretchable electronic systems with simplified process. Specifically, well-controlled contact line pinning effect of printed polymer solution enables the formation of PRIs with tunable thickness; and surface strain analysis on those PRIs leads to the optimized stability and device-to-island fill factor of strain-engineered electronic wraps. Moreover, core techniques of image-based automated pinpointing, surface-mountable device based electronic functionalizing, and one-step interconnection networking of PRIs enable customized circuit design and adaptable functionalities. To exhibit the universality of our approach, multiple types of practical applications ranging from self-computable digital logics to display and sensor system are demonstrated on skin in a customized form.

  15. Fully printable, strain-engineered electronic wrap for customizable soft electronics

    Science.gov (United States)

    Byun, Junghwan; Lee, Byeongmoon; Oh, Eunho; Kim, Hyunjong; Kim, Sangwoo; Lee, Seunghwan; Hong, Yongtaek

    2017-03-01

    Rapid growth of stretchable electronics stimulates broad uses in multidisciplinary fields as well as industrial applications. However, existing technologies are unsuitable for implementing versatile applications involving adaptable system design and functions in a cost/time-effective way because of vacuum-conditioned, lithographically-predefined processes. Here, we present a methodology for a fully printable, strain-engineered electronic wrap as a universal strategy which makes it more feasible to implement various stretchable electronic systems with customizable layouts and functions. The key aspects involve inkjet-printed rigid island (PRI)-based stretchable platform technology and corresponding printing-based automated electronic functionalization methodology, the combination of which provides fully printed, customized layouts of stretchable electronic systems with simplified process. Specifically, well-controlled contact line pinning effect of printed polymer solution enables the formation of PRIs with tunable thickness; and surface strain analysis on those PRIs leads to the optimized stability and device-to-island fill factor of strain-engineered electronic wraps. Moreover, core techniques of image-based automated pinpointing, surface-mountable device based electronic functionalizing, and one-step interconnection networking of PRIs enable customized circuit design and adaptable functionalities. To exhibit the universality of our approach, multiple types of practical applications ranging from self-computable digital logics to display and sensor system are demonstrated on skin in a customized form.

  16. Electrons in Nanostructures

    DEFF Research Database (Denmark)

    Flindt, Christian

    2007-01-01

    in the possibilities o®ered by the quantum mechanical behavior of electrons when it comes to informa- tion processing. This branch of research is also concerned with fundamental questions in physics. Besides an introduction to the above-mentioned subjects, the thesis con- tains a number of contributions to the ¯elds...... of coherent electron manip- ulation and the statistical description of electron transport through nano- devices. The physics of the electrons are described with a combination of numerical methods, developed and applied in the thesis, and more analytical approaches, which are also discussed. The thesis......-based communication. The statistical description of electron transport through nanostructures is based on rate equations, and the primary contribution of the thesis in that respect is the development of a method that allows for the calculation of the distribution of electrons passing through a device. The method...

  17. Identification of electrons in the ZEUS hadron-electron separator with neural networks

    International Nuclear Information System (INIS)

    Carstens, J.O.

    1994-10-01

    An electron finder for the ZEUS experiment was constructed, which is specialized to electrons in the momentum range 0.5 to 3.0 GeV/c. For the first time this electron finder connects the informations of the calorimeter with those of the hadron-electron separator (HES). For this purpose the electron finder was equipped with a neural network. The electron finder reached on a data set of photoproduction events with conversion electrons an efficiency and discriminance of E=(62.9±2.2±0.6)% and D=(91.4±0.8±1.1)%. From these two quantities it can be calculated that the electron finder the ratio electrons to background increases by the factoe E/(1-D)=7.4 (Signal amplification). For the comparison: A neural net, to which only calorimeter informations have been made available, reached at the same efficiency a signal amplification of 2.4. A simple cut in the variable HES-signal reaches a signal amplification of 6.3. Hints were given, how training data sets with electrons and hadrons of higher energies can be obtained. With such data sets the working range of the electron finder can be without problems extended to higher momenta. As preparation for the construction of the electron finder an introduction to the foundations of the mathematics and the application of neural networks was given. By means of examples different methods for the convergence improvement have been tested. Numerous representations mediate illustrative imaginations on the mathematical process of the training of neural networks

  18. Mega-electron-volt ultrafast electron diffraction at SLAC National Accelerator Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Weathersby, S. P.; Brown, G.; Chase, T. F.; Coffee, R.; Corbett, J.; Eichner, J. P.; Frisch, J. C.; Fry, A. R.; Gühr, M.; Hartmann, N.; Hast, C.; Hettel, R.; Jobe, R. K.; Jongewaard, E. N.; Lewandowski, J. R.; Li, R. K., E-mail: lrk@slac.stanford.edu; Lindenberg, A. M.; Makasyuk, I.; May, J. E.; McCormick, D. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025 (United States); and others

    2015-07-15

    Ultrafast electron probes are powerful tools, complementary to x-ray free-electron lasers, used to study structural dynamics in material, chemical, and biological sciences. High brightness, relativistic electron beams with femtosecond pulse duration can resolve details of the dynamic processes on atomic time and length scales. SLAC National Accelerator Laboratory recently launched the Ultrafast Electron Diffraction (UED) and microscopy Initiative aiming at developing the next generation ultrafast electron scattering instruments. As the first stage of the Initiative, a mega-electron-volt (MeV) UED system has been constructed and commissioned to serve ultrafast science experiments and instrumentation development. The system operates at 120-Hz repetition rate with outstanding performance. In this paper, we report on the SLAC MeV UED system and its performance, including the reciprocal space resolution, temporal resolution, and machine stability.

  19. Secondary electron emission anisotropy in oblique incidence of electrons on the (100) Mo

    International Nuclear Information System (INIS)

    Gomoyunova, M.V.; Zaslavskij, S.L.; Pronin, I.I.

    1978-01-01

    Studied was the influence of azimuthal plane of incidence of primary particles with energies of 0.5-1.5 keV on the secondary electron emission of the (100) Mo face at the constant polar angle of 45 deg. The measurements were carried out in vacuum of (2-4)x10 -10 torr by modulation technique. It is shown that anisotropy is peculiar to the secondary electron emission of all energies. The anisotropy of emission has two maxima; the high-energy maximum connected with reflected primary electrons and situated near the elastically reflected electrons and weaker pronounced the low-energy one which is found at energies of 100-200 eV and is conditioned by truly secondary electrons. It is shown that the anisotropy, characterizing secondary electrons responsible for the appearance of structure in spectrum, particularly the Auger electrons and the electrons suffering ionizing energy losses, exceeds the anisotropy of continuous spectrum electrons possessing the same energy. The electron diffraction dynamic theory, based on the conception of the united wave field of electrons, has been used to explain the regularities stated

  20. Kinetic and electron-electron energies for convex sums of ground state densities with degeneracies and fractional electron number

    Energy Technology Data Exchange (ETDEWEB)

    Levy, Mel, E-mail: ayers@mcmaster.ca, E-mail: mlevy@tulane.edu [Department of Chemistry, Duke University, Durham, North Carolina 27708 (United States); Department of Physics, North Carolina A and T State University, Greensboro, North Carolina 27411 (United States); Department of Chemistry, Tulane University, New Orleans, Louisiana 70118 (United States); Anderson, James S. M.; Zadeh, Farnaz Heidar; Ayers, Paul W., E-mail: ayers@mcmaster.ca, E-mail: mlevy@tulane.edu [Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario (Canada)

    2014-05-14

    Properties of exact density functionals provide useful constraints for the development of new approximate functionals. This paper focuses on convex sums of ground-level densities. It is observed that the electronic kinetic energy of a convex sum of degenerate ground-level densities is equal to the convex sum of the kinetic energies of the individual degenerate densities. (The same type of relationship holds also for the electron-electron repulsion energy.) This extends a known property of the Levy-Valone Ensemble Constrained-Search and the Lieb Legendre-Transform refomulations of the Hohenberg-Kohn functional to the individual components of the functional. Moreover, we observe that the kinetic and electron-repulsion results also apply to densities with fractional electron number (even if there are no degeneracies), and we close with an analogous point-wise property involving the external potential. Examples where different degenerate states have different kinetic energy and electron-nuclear attraction energy are given; consequently, individual components of the ground state electronic energy can change abruptly when the molecular geometry changes. These discontinuities are predicted to be ubiquitous at conical intersections, complicating the development of universally applicable density-functional approximations.