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Sample records for delphinapterus leucas electronic

  1. True hermaphroditism in a St. Lawrence beluga whale (Delphinapterus leucas).

    Science.gov (United States)

    De Guise, S; Lagacé, A; Béland, P

    1994-04-01

    A hermaphrodite beluga whale (Delphinapterus leucas) was found in the St. Lawrence Estuary, Québec, Canada. This animal had two testicles, two separate ovaries, and the complete ducts of each sex; cervix, vagina and vulva were absent. Mature spermatozoa were found in the lumen of seminiferous tubules in the testicles, and numerous involuted corpora lutea were recognized in the ovaries. This represents the first case of true hermaphroditism in a cetacean, and is the fourth hermaphrodite mammal with two testicles and two separate ovaries.

  2. Passive acoustic monitoring of Cook Inlet beluga whales (Delphinapterus leucas).

    Science.gov (United States)

    Lammers, Marc O; Castellote, Manuel; Small, Robert J; Atkinson, Shannon; Jenniges, Justin; Rosinski, Anne; Oswald, Julie N; Garner, Chris

    2013-09-01

    The endangered beluga whale (Delphinapterus leucas) population in Cook Inlet, AK faces threats from a variety of anthropogenic factors, including coastal development, oil and gas exploration, vessel traffic, and military activities. To address existing gaps in understanding about the occurrence of belugas in Cook Inlet, a project was developed to use passive acoustic monitoring to document the year-round distribution of belugas, as well as killer whales (Orcinus orca), which prey on belugas. Beginning in June 2009, ten moorings were deployed throughout the Inlet and refurbished every two to eight months. Despite challenging conditions consisting of strong tidal currents carrying debris and seasonal ice cover, 83% of mooring deployments were successfully recovered. Noise from water flow, vessel traffic, and/or industrial activities was present at several sites, potentially masking some signals. However, belugas were successfully detected at multiple locations. Detections were relatively common in the upper inlet and less common or absent at middle and lower inlet locations. Killer whale signals were also recorded. Some seasonal variability in the occurrence of both belugas and killer whales was evident.

  3. Tumors in St. Lawrence beluga whales (Delphinapterus leucas)

    Science.gov (United States)

    De Guise, S; Lagacé, A; Béland, P

    1994-07-01

    A population of 450-500 belugas (Delphinapterus leucas) resides in the polluted estuary of the St. Lawrence River. Stranded carcasses of this endangered population were recovered and necropsied. High concentrations of organochlorines, heavy metals, and benzo-a-pyrene exposure were demonstrated in tissues of these whales. Between 1988 and 1990, 21 tumors were found in 12 out of 24 carcasses. Among these tumors, six were malignant and 15 were benign. The animals were between 1.5 and > 29 years of age, and the ages of animals with and without tumors did not differ when two juvenile animals (1.5 and 3.5 years of age) were excluded. Seven other neoplasms had been reported previously in six out of 21 well-preserved carcasses examined in the same laboratory between 1982 and 1987. Overall, 28 of the 75 confirmed tumors reported so far in cetaceans (37%) were from this small population of beluga whales in the St. Lawrence Estuary. Such a high prevalence of tumors would suggest an influence of contaminants through a direct carcinogenic effect and/or a decreased resistance to the development of tumors in this population.

  4. Young Belugas Diversify Adult Beluga (Delphinapterus leucas Behavior

    Directory of Open Access Journals (Sweden)

    Heather Hill

    2015-08-01

    Full Text Available Across the animal kingdom, immature animals are characterized by their playfulness and diversity of behavior, but are their actions enriching to adult conspecifics? The purpose of this study was to assess if beluga (Delphinapterus leucas calves influenced the behavioral repertoire of adult conspecifics, specifically with regard to play behaviors, social interactions, and solitary swimming. Video recordings made between 2012 and 2015 (200+ hrs were randomly selected using the following social groupings: adults only (n = 13, adults with juvenile (n = 28, mother-calf pairs (n = 24, mother-calf pairs with juvenile (n = 26, and mixed groups (n = 84 that included different ages and sexes. Each recording was coded using a 1-min instantaneous sampling method for 7 behavioral categories that were grouped into 4 major categories: mother-calf swim, social interactions, play, and solitary swims. Results indicated that the social grouping influenced the behavioral categories even when number of animals in the social grouping was controlled. Adults displayed solitary swims significantly (p < 0.001 more often when grouped with each other (adjusted M = 86% or with juvenile belugas (adjusted M = 85% than any other combination in which calves were present (adjusted M ranged between 42% – 64%. The presence of calves also significantly (p = 0.002 increased the number of play activities observed for adults (Adults only: adjusted M < 0%; Mixed: adjusted M = 11%. The percent of social interactions did not significantly (p = 0.196 change across the different social groupings. The results demonstrate that the presence of beluga calves decreased the percent of time adults spent in solitary swims and increased the percent of time adults spent in other activities, including play behaviors and social interactions. The presence of beluga calves is associated with increased diversity of the behavioral repertoires of adult conspecifics.

  5. Belugas (Delphinapterus leucas of the Barents, Kara and Laptev seas

    Directory of Open Access Journals (Sweden)

    Andrei N Boltunov

    2002-07-01

    Full Text Available This paper reviews published information on the white whale or beluga (Delphinapterus leucas inhabiting the Barents, Kara and Laptev seas. Some data obtained during multi-year aerial reconnaissance of sea ice in the Russian Arctic are also included. Ice conditions, considered one of the major factors affecting distribution of belugas, are described. The number of belugas inhabiting the Russian Arctic is unknown. Based on analysis of published and unpublished information we believe that the primary summer habitats of belugas in the Western Russian Arctic lie in the area of Frants-Josef Land, in the Kara Sea and in the western Laptev Sea. Apparently most belugas winter in the Barents Sea. Although it has been suggested that a considerable number of animals winter in the Kara Sea, there is no direct evidence for this. Apparent migrations of animals are regularly observed at several sites: the straits of the Novaya Zemlya Archipelago, the waters north of the archipelago, and Vilkitskiy Strait between the Kara and Laptev seas. Calving and mating take place in summer, and the beluga mother feeds a calf for at least a year. Females mature earlier than males, and about 30% of mature females in a population are barren. Sex ratio is apparently close to 1:1. The diet of the beluga in the region includes fish and crustaceans and shows considerable spatial and temporal variations. However, polar cod (Boreogadus saida is the main prey most of the year, and whitefish (Coregonidae contribute in coastal waters in summer. Usually belugas form groups of up to 10 related individuals of different ages, while large aggregations are common during seasonal migrations or in areas with abundant and easily available food. Beluga whaling in Russia has a history of several centuries. The highest catches were taken in the 1950s and 1960s, when about 1,500 animals were caught annually in the Western Russian Arctic. In the 1990s, few belugas were

  6. Beluga whale (Delphinapterus leucas) vocalizations and call classification from the eastern Beaufort Sea population

    OpenAIRE

    2015-01-01

    Funding was provided by the Bureau of Ocean Energy Management under InterAgency Agreement M09PG00016. E.C.G. was supported by a National Research Council (National Academy of Sciences) Postdoctoral Fellowship. Beluga whales, Delphinapterus leucas, have a graded call system; call types exist on a continuum making classification challenging. A description of vocalizations from the eastern Beaufort Sea beluga population during its spring migration are presented here, using both a non-parametr...

  7. Possible mechanisms of action of environmental contaminants on St. Lawrence beluga whales (Delphinapterus leucas).

    OpenAIRE

    de Guise, S.; Martineau, D.; Béland, P; Fournier, M.

    1995-01-01

    A small isolated population of beluga whales (Delphinapterus leucas) that are highly contaminated by pollutants, mostly of industrial origin, resides in the St. Lawrence estuary, Québec, Canada. Overhunting in the first half of the century was the probable cause for this population to dwindle from several thousand animals to the current estimate of 500. The failure of the population to recover might be due to contamination by organochlorine compounds, which are known to lead to reproductive f...

  8. Dermatophilus-like infection in beluga whales, Delphinapterus leucas, from the St. Lawrence estuary.

    Science.gov (United States)

    Mikaelian, I; Lapointe, J M; Labelle, P; Higgins, R; Paradis, M; Martineau, D

    2001-02-01

    Six beluga whales (Delphinapterus leucas) found dead on the shores of the St. Lawrence estuary had multiple slightly depressed greyish round areas randomly distributed over the whole body. Histologically, the surface of these areas was covered with a thick layer of Dermatophilus-like organisms which invaded the stratum corneum. The underlying stratum spinosum had marked spongiosis and vacuolar degeneration. Minimal neutrophilic infiltration was present within the underlying dermal papillae. To the authors' knowledge, dermatophilosis in cetaceans has not been reported previously.

  9. Exchange of “signature” calls in captive belugas (Delphinapterus leucas)

    OpenAIRE

    Morisaka, Tadamichi; Yoshida, Yayoi; Akune, Yuichiro; Mishima, Hideki; Nishimoto, Sayo

    2013-01-01

    Belugas (Delphinapterus leucas) produce echolocation clicks, burst pulses, and whistles. The sounds of 3 captive belugas were recorded using 2 hydrophones at the Port of Nagoya Public Aquarium. There were stable individual differences in the pulse patterning of one type of pulsed sounds (PS1 call), suggesting that belugas use these as “signature” calls. Eighty-eight percent of PS1 calls initiated PS1 calls from other animals within 1 s. PS1 calls repeated by the same individual occurred prima...

  10. The effect of sea-ice loss on beluga whales (Delphinapterus leucas) in West Greenland

    DEFF Research Database (Denmark)

    Heide-Jørgensen, M.P.; Laidre, K.L.; Simon, Malene Juul

    2009-01-01

    An aerial survey was conducted to estimate the abundance of belugas (Delphinapterus leucas) on their wintering ground in West Greenland in March-April 2006 and 2008. The survey was conducted as a double platform aerial line transect survey, and sampled approximately 17% of the total survey area o...

  11. Beluga whale, Delphinapterus leucas, vocalizations and their relation to behaviour in the Churchill River, Manitoba, Canada

    Science.gov (United States)

    Chmelnitsky, Elly Golda

    The investigation of a species' repertoire and the contexts in which different calls are used is central to understanding vocal communication among animals. Beluga whale, Delphinapterus leucas, calls were classified and described in association with behaviours, from recordings collected in the Churchill River, Manitoba, during the summers of 2006-2008. Calls were subjectively classified based on sound and visual analysis into whistles (64.2% of total calls; 22 call types), pulsed or noisy calls (25.9%; 15 call types), and combined calls (9.9%; seven types). A hierarchical cluster analysis, using six call measurements as variables, separated whistles into 12 groups and results were compared to subjective classification. Beluga calls associated with social interactions, travelling, feeding, and interactions with the boat were described. Call type percentages, relative proportions of different whistle contours (shapes), average frequency, and call duration varied with behaviour. Generally, higher percentages of whistles, more broadband pulsed and noisy calls, and shorter calls (<0.49s) were produced during behaviours associated with higher levels of activity and/or apparent arousal. Information on call types, call characteristics, and behavioural context of calls can be used for automated detection and classification methods and in future studies on call meaning and function.

  12. Relative quantity judgments in the beluga whale (Delphinapterus leucas) and the bottlenose dolphin (Tursiops truncatus).

    Science.gov (United States)

    Abramson, José Z; Hernández-Lloreda, Victoria; Call, Josep; Colmenares, Fernando

    2013-06-01

    Numerous studies have documented the ability of many species to make relative quantity judgments using an analogue magnitude system. We investigated whether one beluga whale, Delphinapterus leucas, and three bottlenose dolphins, Tursiops truncatus, were capable of selecting the larger of two sets of quantities, and analyzed if their performance matched predictions from the object file model versus the analog accumulator model. In Experiment 1, the two sets were presented simultaneously, under water, and they were visually (condition 1) or echoically (condition 2) available at the time of choice. In experiment 2, the two sets were presented above the water, successively (condition 1) or sequentially, item-by-item (condition 2), so that they were not visually available at the time of choice (condition 1) or at any time throughout the experiment (condition 2). We analyzed the effect of the ratio between quantities, the difference between quantities, and the total number of items presented on the subjects' choices. All subjects selected the larger of the two sets of quantities above chance levels in all conditions. However, unlike most previous studies, the subjects' choices did not match the predictions from the accumulator model. Whether these findings reflect interspecies differences in the mechanisms which underpin relative quantity judgments remains to be determined.

  13. Molecular cloning and characterization of CD4 in an aquatic mammal, the white whale Delphinapterus leucas.

    Science.gov (United States)

    Romano, T A; Ridgway, S H; Felten, D L; Quaranta, V

    1999-05-01

    Given the importance of the cell surface recognition protein, CD4, in immune function, the cloning and characterization of CD4 at the molecular level from an odontocete cetacean, the white whale (Delphinapterus leucas), was carried out. Whale CD4 cDNA contains 2662 base pairs and translates into a protein containing 455 amino acids. Whale CD4 shares 64% and 51% identity with the human and mouse CD4 protein, respectively, and is organized in a similar manner. Unlike human and mouse, however, the cytoplasmic domain, which is highly conserved, contains amino acid substitutions unique to whale. Moreover, only one of the seven potential N-linked glycosylation sites present in whale is shared with human and mouse. Evolutionarily, the whale CD4 sequence is most similar to pig and structurally similar to dog and cat, in that all lack the cysteine pair in the V2 domain. These differences suggest that CD4 may have a different secondary structure in these species, which may affect binding of class II and subsequent T-cell activation, as well as binding of viral pathogens. Interestingly, as a group, species with these CD4 characteristics all have high constitutive expression of class II molecules on T lymphocytes, suggesting potential uniqueness in the interaction of CD4, class II molecules, and the immune response. Molecular characterization of CD4 in an aquatic mammal provides information on the CD4 molecule itself and may provide insight into adaptive evolutionary changes of the immune system.

  14. PCBs are associated with altered gene transcript profiles in arctic Beluga Whales (Delphinapterus leucas).

    Science.gov (United States)

    Noël, Marie; Loseto, Lisa L; Helbing, Caren C; Veldhoen, Nik; Dangerfield, Neil J; Ross, Peter S

    2014-01-01

    High trophic level arctic beluga whales (Delphinapterus leucas) are exposed to persistent organic pollutants (POP) originating primarily from southern latitudes. We collected samples from 43 male beluga harvested by Inuvialuit hunters (2008-2010) in the Beaufort Sea to evaluate the effects of POPs on the levels of 13 health-related gene transcripts using quantitative real-time polymerase chain reaction. Consistent with their role in detoxification, the aryl hydrocarbon receptor (Ahr) (r(2) = 0.18, p = 0.045 for 2008 and 2009) and cytochrome P450 1A1 (Cyp1a1) (r(2) = 0.20, p development. Factor 1 explained 56% of gene profiles, with these latter 11 gene transcripts displaying greater abundance in years coinciding with periods of low sea ice extent (2008 and 2010). δ(13)C results suggested a shift in feeding ecology and/or change in condition of these ice edge-associated beluga whales during these two years. While this provides insight into the legacy of PCBs in a remote environment, the possible impacts of a changing ice climate on the health of beluga underscores the need for long-term studies.

  15. Beluga whale (Delphinapterus leucas) vocalizations and call classification from the eastern Beaufort Sea population.

    Science.gov (United States)

    Garland, Ellen C; Castellote, Manuel; Berchok, Catherine L

    2015-06-01

    Beluga whales, Delphinapterus leucas, have a graded call system; call types exist on a continuum making classification challenging. A description of vocalizations from the eastern Beaufort Sea beluga population during its spring migration are presented here, using both a non-parametric classification tree analysis (CART), and a Random Forest analysis. Twelve frequency and duration measurements were made on 1019 calls recorded over 14 days off Icy Cape, Alaska, resulting in 34 identifiable call types with 83% agreement in classification for both CART and Random Forest analyses. This high level of agreement in classification, with an initial subjective classification of calls into 36 categories, demonstrates that the methods applied here provide a quantitative analysis of a graded call dataset. Further, as calls cannot be attributed to individuals using single sensor passive acoustic monitoring efforts, these methods provide a comprehensive analysis of data where the influence of pseudo-replication of calls from individuals is unknown. This study is the first to describe the vocal repertoire of a beluga population using a robust and repeatable methodology. A baseline eastern Beaufort Sea beluga population repertoire is presented here, against which the call repertoire of other seasonally sympatric Alaskan beluga populations can be compared.

  16. Matriarchal genetic population structure of North American beluga whales Delphinapterus leucas (Cetacea: Monodontidae).

    Science.gov (United States)

    Brown Gladden, J G; Ferguson, M M; Clayton, J W

    1997-11-01

    The North American beluga whale Delphinapterus leucas population has been divided into a number of putative geographical stocks based upon migration routes and areas of summer concentration. Nucleotide sequences of the mitochondrial DNA (mtDNA) control region were used to assess whether these geographical stocks are genetically distinct. Beluga whale samples from 25 sites were collected primarily from aboriginal subsistence hunts across North America from 1984 to 1994. Thirty-nine mtDNA haplotypes were identified in 628 beluga samples. No differences were found in the distribution of haplotypes between male and female beluga whales at any sampling site. These haplotypes segregated into two distinct assemblages in both a haplotype network and a neighbour-joining tree. The haplotype assemblages and a geographically disjunct distribution that suggests postglacial recolonization of the North American Arctic from two different refugia. An analysis of molecular variance based on haplotype relationships and frequency indicated genetic heterogeneity among beluga whale summering groups (P St Lawrence River and the western or central Arctic. The results of this study show a high degree of philopatry to specific summering areas by this highly mobile animal.

  17. Identification of a novel herpesvirus associated with a penile proliferative lesion in a beluga (Delphinapterus leucas).

    Science.gov (United States)

    Bellehumeur, Christian; Lair, Stéphane; Romero, Carlos H; Provost, Chantale; Nielsen, Ole; Gagnon, Carl A

    2015-01-01

    The carcass of an adult male beluga (Delphinapterus leucas) was found beach cast in 2008 on the shore of the St. Lawrence Estuary at Rivière-Ouelle, Quebec, Canada. The carcass was transported to the Faculté de médecine vétérinaire of the Université de Montréal for postmortem examination. Aspiration pneumonia was the probable cause of death. Necropsy revealed a focal papilloma-like penile lesion, characterized by focal mucosal thickening with disorganization of the epithelial layers and lymphoplasmacytic infiltration. A pan-herpesvirus nested PCR assay on frozen tissue from the penile lesion was positive. The PCR product sequencing revealed a partial herpesvirus DNA polymerase (DPOL) gene sequence of 600 nucleotides. Its nearest nucleotide identity was with the partial DPOL gene of an alphaherpesvirus, bovine herpesvirus 5 (79.5% identity). It also shared high identity with several other marine mammal herpesviruses (50.2 to 77.3% identity). This new herpesvirus was tentatively named beluga whale herpesvirus (BWHV). Virus isolation was unsuccessful. The pathogenic potential of BWHV is unknown, but the evaluation of archived tissues suggests that the virus is endemic in the St. Lawrence Estuary beluga population.

  18. Teeth as biomonitors of selenium concentrations in tissues of beluga whales (Delphinapterus leucas)

    Energy Technology Data Exchange (ETDEWEB)

    Kinghorn, April [Centre for Indigenous Peoples Nutrition and Environment, Macdonald Campus, McGill University, 21-111 Lakeshore Road, Ste. Anne-de-Bellevue, Quebec, H9X 3V9 (Canada); Humphries, Murray M. [Centre for Indigenous Peoples Nutrition and Environment, Macdonald Campus, McGill University, 21-111 Lakeshore Road, Ste. Anne-de-Bellevue, Quebec, H9X 3V9 (Canada); Department of Natural Resource Science, Macdonald Campus, McGill University, 21-111 Lakeshore Road, Ste. Anne-de-Bellevue, Quebec, H9X 3V9 (Canada); Outridge, Peter [Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario, K1A 0E8 (Canada); Chan, Hing Man [Community Health Sciences Program, University of Northern British Columbia, 3333 University Way, Prince George, British Columbia, V2N 4Z9 (Canada)], E-mail: lchan@unbc.ca

    2008-08-25

    Selenium (Se) is an essential element which has been shown to play an important role in protecting marine mammals against the toxic effects of mercury (Hg) and other metals. It has been suggested that metal concentration in marine mammal teeth can potentially be used as bioindicators for body burden. The objective of this study was to investigate the relationship between Se concentrations in beluga (Delphinapterus leucas) teeth and those previously measured in soft tissues (liver, kidney, muscle and muktuk). Tooth Hg concentrations are also measured, and the relationships between Se and Hg in teeth and soft tissues are examined. Se in the teeth of beluga was measured using hydride generation atomic fluorescence spectrometry (HG-AFS) and Hg in beluga teeth was measured by cold-vapour atomic absorption. Tooth Se concentrations ranged from 108 ng/g to 245 ng/g dry weight, and tooth Hg concentrations ranged from 10 to 189 ng/g dry weight. In the soft tissues, Se concentrations were highest in the liver, followed by kidney, muktuk, and muscle. There were significant correlations between tooth Se concentrations and animal age, tooth Se and liver and muscle Se, and between liver Se and animal age. The molar ratio of Hg:Se in the liver was found to be 0.70. This study is the first to measure Se in the teeth of a marine mammal species, and HG-AFS is found to be an effective technique for determining Se in beluga teeth. Tooth Se can be used as predictor for liver and muscle Se, although these relationships may be strongly influenced by the association of Se with Hg in marine mammal tissues. This study contributes to an increased understanding of the storage and metabolism of Se in marine mammals.

  19. Levels of toxaphene congeners in white whales (Delphinapterus leucas) from Svalbard, Norway.

    Science.gov (United States)

    Andersen, G; Føreid, S; Skaare, J U; Jenssen, B M; Lydersen, C; Kovacs, K M

    2006-03-15

    This study reports concentrations of three pesticide toxaphene congeners (CHBs; CHB-26, -50 and -62) from the blubber of ten adult, male white whales (Delphinapterus leucas) from Svalbard, Norway. The CHB congeners that occurred at the highest levels in the blubber of the white whales were, as expected, CHB-26 (4636+/-1992 (SD) ng/g l.w.) and CHB-50 (6579+/-2214 ng/g l.w.); CHB-62 (232+/-231 ng/g l.w.) was also present, but at much lower concentrations. The mean level of the sum of the three CHBs (SigmaCHBs = 11,447+/-4208 ng/g l.w.) in this study is more than twice the mean concentrations of the well-known organochlorine (OC) pollutants SigmaDDTs (sum of pp'-DDT, pp'-DDE, pp'-DDD) and SigmaPCBs (sum of 27 PCB congeners) previously reported from the same individual white whales. The concentrations of CHBs in white whales from Svalbard are at the high end of the range for concentrations of these compounds compared to other Arctic white whale populations. Additionally, the contribution of CHBs to the overall OC burden is larger in white whales from Svalbard compared with their counterparts from other areas in the Arctic. Male white whales from Svalbard have several orders of magnitude higher concentrations of SigmaCHBs compared to seals and polar bears (Ursus maritimus) from the same area. The high levels of CHBs in these whales, and their dominance in the OC pattern, suggests that white whales in Svalbard are exposed to high levels of this group of contaminants. Further studies are needed to investigate possible effects of CHBs and other OC contaminants on the white whale population in Svalbard.

  20. Blow collection as a non-invasive method for measuring cortisol in the beluga (Delphinapterus leucas.

    Directory of Open Access Journals (Sweden)

    Laura A Thompson

    Full Text Available Non-invasive sampling techniques are increasingly being used to monitor glucocorticoids, such as cortisol, as indicators of stressor load and fitness in zoo and wildlife conservation, research and medicine. For cetaceans, exhaled breath condensate (blow provides a unique sampling matrix for such purposes. The purpose of this work was to develop an appropriate collection methodology and validate the use of a commercially available EIA for measuring cortisol in blow samples collected from belugas (Delphinapterus leucas. Nitex membrane stretched over a petri dish provided the optimal method for collecting blow. A commercially available cortisol EIA for measuring human cortisol (detection limit 35 pg ml-1 was adapted and validated for beluga cortisol using tests of parallelism, accuracy and recovery. Blow samples were collected from aquarium belugas during monthly health checks and during out of water examination, as well as from wild belugas. Two aquarium belugas showed increased blow cortisol between baseline samples and 30 minutes out of water (Baseline, 0.21 and 0.04 µg dl-1; 30 minutes, 0.95 and 0.14 µg dl-1. Six wild belugas also showed increases in blow cortisol between pre and post 1.5 hour examination (Pre 0.03, 0.23, 0.13, 0.19, 0.13, 0.04 µg dl-1, Post 0.60, 0.31, 0.36, 0.24, 0.14, 0.16 µg dl-1. Though this methodology needs further investigation, this study suggests that blow sampling is a good candidate for non-invasive monitoring of cortisol in belugas. It can be collected from both wild and aquarium animals efficiently for the purposes of health monitoring and research, and may ultimately be useful in obtaining data on wild populations, including endangered species, which are difficult to handle directly.

  1. Possible mechanisms of action of environmental contaminants on St. Lawrence beluga whales (Delphinapterus leucas).

    Science.gov (United States)

    De Guise, S; Martineau, D; Béland, P; Fournier, M

    1995-05-01

    A small isolated population of beluga whales (Delphinapterus leucas) that are highly contaminated by pollutants, mostly of industrial origin, resides in the St. Lawrence estuary, Québec, Canada. Overhunting in the first half of the century was the probable cause for this population to dwindle from several thousand animals to the current estimate of 500. The failure of the population to recover might be due to contamination by organochlorine compounds, which are known to lead to reproductive failure and immunosuppression in domestic and laboratory animals and seals. Functional and morphological changes have been demonstrated in thyroid gland and adrenal cortex in many species exposed to organochlorinated compounds, including seals. Morphological lesions, although different, were also found in belugas. Functional evaluation of thyroid and adrenal glands of contaminated (St. Lawrence) versus much less contaminated (Arctic) belugas is currently under way. Necropsy of St. Lawrence belugas showed numerous severe and disseminated infections with rather mildly pathogenic bacteria, which suggests immunosuppression. Organochlorine compounds and other contaminants found in beluga whales cause immunosuppression in a variety of animal species including seals. Thirty-seven percent of all the tumors reported in cetaceans were observed in St. Lawrence beluga whales. This could be explained by two different mechanisms: high exposure to environmental carcinogens and suppression of immunosurveillance against tumors. Overall, St. Lawrence belugas might well represent the risk associated with long-term exposure to pollutants present in their environment and might be a good model to predict health problems that could emerge in highly exposed human populations over time.

  2. Sequence variation at the major histocompatibility complex locus DQ beta in beluga whales (Delphinapterus leucas)

    Science.gov (United States)

    Murray, B W; Malik, S; White, B N

    1995-07-01

    Genetic variation at the Major Histocompatibility Complex locus DQ beta was analyzed in 233 beluga whales (Delphinapterus leucas) from seven populations: St. Lawrence Estuary, eastern Beaufort Sea, eastern Chukchi Sea, western Hudson Bay, eastern Hudson Bay, southeastern Baffin Island, and High Arctic and in 12 narwhals (Monodon monoceros) sympatric with the High Arctic beluga population. Variation was assessed by amplification of the exon coding for the peptide binding region via the polymerase chain reaction, followed by either cloning and DNA sequencing or single-stranded conformation polymorphism analysis. Five alleles were found across the beluga populations and one in the narwhal. Pairwise comparisons of these alleles showed a 5:1 ratio of nonsynonymous to synonymous substitutions per site leading to eight amino acid differences, five of which were nonconservative substitutions, centered around positions previously shown to be important for peptide binding. Although the amount of allelic variation is low when compared with terrestrial mammals, the nature of the substitutions in the peptide binding sites indicates an important role for the DQ beta locus in the cellular immune response of beluga whales. Comparisons of allele frequencies among populations show the High Arctic population to be different (P < or = .005) from the other beluga populations surveyed. In these other populations an allele, Dele-DQ beta*0101-2, was found in 98% of the animals, while in the High Arctic it was found in only 52% of the animals. Two other alleles were found at high frequencies in the High Arctic population, one being very similar to the single allele found in narwhal.

  3. Concentrations and patterns of organochlorine contaminants in white whales (Delphinapterus leucas) from Svalbard, Norway.

    Science.gov (United States)

    Andersen, G; Kovacs, K M; Lydersen, C; Skaare, J U; Gjertz, I; Jenssen, B M

    2001-01-17

    Blubber was collected from live-captured, adult male white whales (Delphinapterus leucas) from Svalbard, Norway, and analysed for levels and patterns of organochlorine (OC) contaminants. The OC compounds analysed were HCB, dieldrin, sigmaHCH (alpha-HCH, beta-HCH and gamma-HCH), sigmaChl (heptachlor epoxide, oxychlordane, cis-chlordane, trans-nonachlor, and cis-nonachlor), sigmaDDT (pp'-DDT, pp'-DDE and pp'-DDD) and sigmaPCB (27 PCB congeners). The major OC compounds detected in the blubber were sigmaPCB (5103+/-1874 ng/g l.w.) and sigmaDDT (5108+/-1089 ng/g l.w.), which made up 70% of the sigmaOC. These compounds were followed in prevalence by sigmaChl (2872+/-1177 ng/g l.w.), which contributed 20% of the sigmaOC burden. SigmaHCH, HCB and dieldrin were present, but at low concentrations. This OC pattern is typical of top predators in Arctic marine food chains. OC levels in white whales from Svalbard are lower than white whales from the St Lawrence River in Canada and are generally similar to values reported previously for other Arctic white whale stocks. Some geographic patterns in relative prevalence of various OC compounds appear to be quite consistent among various marine mammal species in the Arctic. PCB and DDT concentrations in Svalbard's white whales are below the levels that are thought to have negative effects on reproduction or the immune system.

  4. Organohalogen contaminants and metabolites in beluga whale (Delphinapterus leucas) liver from two Canadian populations.

    Science.gov (United States)

    McKinney, Melissa A; De Guise, Sylvain; Martineau, Daniel; Béland, Pierre; Lebeuf, Michel; Letcher, Robert J

    2006-05-01

    Contaminants described as organochlorines (OCs; e.g., polychlorinated biphenyls [PCBs]) are present in tissues of marine mammals, including beluga whales (Delphinapterus leucas), but the complexity of contaminant exposure often is not fully known. The PCBs, OC pesticides, polybrominated diphenyl ether (PBDE) flame retardants, methylsulfonyl (MeSO2)- and hydroxy (OH)-PCB metabolites, and OH-PBDEs and methoxylated (MeO)-PBDEs were determined in the liver of beluga whales from two Canadian populations: the St. Lawrence Estuary (SLB; n=6), and western Hudson Bay in the Canadian Arctic (CAB; n=11). The sigmaPCB, sigmaDDT, and sigmaPBDE concentrations were higher (p < 0.05) in SLB versus CAB. Of 18 detectable OH-PCBs in SLB (mainly 4-OH-CB107, 4-OH-CB112, and 4'-OH-CB120), only 4'-OH-CB120 was found in CAB. The sigmaOH-PCB concentrations were less than 0.2% of the sigmaPCBs in both populations but were higher (p < 0.05) in SLB (65 +/- 22 ng/g lipid wt) than in CAB (3.1 +/- 0.5 ng/g lipid wt). The sigmaMeSO2-PCB concentrations were higher in SLB (3801 +/- 1322 ng/g lipid wt) relative to CAB (77 +/- 23 ng/g lipid wt) and were 11 and 4%, respectively, of the sigmaPCB concentrations. Of the 15 OH-PBDEs, only two congeners were detectable, but not quantifiable (notably 2'-OH-BDE 68 and 6-OH-BDE 47), in animals from both populations. Of the 15 MeO-PBDEs, 4'-MeO-BDE 17 and 6-MeO-BDE 47 in the SLB (n=2) and 2'-MeO-BDE 68 and 6-MeO-BDE 47 in the CAB (n=2) had concentrations from 20 to 100 ng/g lipid weight. The OH-PBDEs and MeO-PBDEs most likely are of natural origin and accumulated in beluga whales, whereas the OH-PCBs and MeSO2-PCBs are metabolites derived from accumulated PCBs. Canadian beluga whale liver contains previously unidentified organohalogen contaminants and metabolites and, thus, a complexity of contaminant exposure that may be impacting the health of Canadian beluga whale populations.

  5. The first year of behavioral development and maternal care of beluga (Delphinapterus leucas) calves in human care.

    Science.gov (United States)

    Hill, Heather M; Campbell, Carolyn; Dalton, Les; Osborn, Steven

    2013-01-01

    The current study provides additional information for the behavioral development and maternal care of belugas or white whales (Delphinapterus leucas) in the care of humans. The behaviors and mother-calf interactions of two female beluga calves were recorded from birth to 12 months as part of a longitudinal study of beluga behavioral development. As expected, the primary calf activity for both calves involved swimming with their mothers. The calves initiated the majority of the separations from and reunions with their mothers and exhibited early bouts of independence. Both mothers bonded with their calves and displayed similar maternal care behaviors but exhibited different behavioral patterns. Despite differences in social groupings, housing, and physical health, the two female belugas followed the behavioral development of beluga calves observed previously.

  6. Concentrations of Polychlorinated Biphenyls (PCB’s), Chlorinated Pesticides, and Heavy Metals and Other Elements in Tissues of Belugas, Delphinapterus leucas, from Cook Inlet

    OpenAIRE

    Becker, Paul R.; Krahn, Margaret M.; Mackey, Elizabeth A.; Demiralp, Rabia; Schantz, Michele M.; Epstein, Michael S.; Donais, Mary Kate; Porter, Barbara J.; Derek C G Muir; Wise, Stephen A.

    2000-01-01

    Tissues from Cook Inlet beluga whales, Delphinapterus leucas, that were collected as part of the Alaska Marine Mammal Tissue Archival Project were analyzed for polychlorinated biphenyls (PCB’s), chlorinated pesticides, and heavy metals and other elements. Concentrations of total PCB’s (ΣPCB’s), total DDT (ΣDDT), chlordane compounds, hexachlorobenzene (HCB), dieldrin, mirex, toxaphene, and hexachlorocyclohexane (HCH) measured in Cook Inlet beluga blubber were compared with those reported for b...

  7. Mercury distribution and speciation in different brain regions of beluga whales (Delphinapterus leucas)

    Energy Technology Data Exchange (ETDEWEB)

    Ostertag, Sonja K., E-mail: ostertag@unbc.ca [Natural Resources and Environmental Studies, University of Northern British Columbia, Prince George, British Columbia, V2N 4Z9 (Canada); Stern, Gary A., E-mail: Gary.Stern@dfo-mpo.gc.ca [Freshwater Institute, Fisheries and Oceans Canada, Winnipeg, Manitoba, R3T 2N6 (Canada); Centre for Earth Observation Science, Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba, R3T 2N2 (Canada); Wang, Feiyue, E-mail: feiyue.wang@ad.umanitoba.ca [Centre for Earth Observation Science, Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba, R3T 2N2 (Canada); Department of Chemistry, University of Manitoba, Winnipeg, Manitoba, R3T 2N2 (Canada); Lemes, Marcos, E-mail: Marcos.lemes@ad.umanitoba.ca [Centre for Earth Observation Science, Department of Environment and Geography, University of Manitoba, Winnipeg, Manitoba, R3T 2N2 (Canada); Chan, Hing Man, E-mail: laurie.chan@uottawa.ca [Center for Advanced Research in Environmental Genomics, University of Ottawa, Ottawa, Ontario, 1N 6N5 (Canada)

    2013-07-01

    The toxicokinetics of mercury (Hg) in key species of Arctic ecosystem are poorly understood. We sampled five brain regions (frontal lobe, temporal lobe, cerebellum, brain stem and spinal cord) from beluga whales (Delphinapterus leucas) harvested in 2006, 2008, and 2010 from the eastern Beaufort Sea, Canada, and measured total Hg (HgT) and total selenium (SeT) by inductively coupled plasma mass spectrometry (ICP-MS), mercury analyzer or cold vapor atomic absorption spectrometry, and the chemical forms using a high performance liquid chromatography ICP-MS. At least 14% of the beluga whales had HgT concentrations higher than the levels of observable adverse effect (6.0 mg kg{sup −1} wet weight (ww)) in primates. The concentrations of HgT differed between brain regions; median concentrations (mg kg{sup −1} ww) were 2.34 (0.06 to 22.6, 81) (range, n) in temporal lobe, 1.84 (0.12 to 21.9, 77) in frontal lobe, 1.84 (0.05 to 16.9, 83) in cerebellum, 1.25 (0.02 to 11.1, 77) in spinal cord and 1.32 (0.13 to 15.2, 39) in brain stem. Total Hg concentrations in the cerebellum increased with age (p < 0.05). Between 35 and 45% of HgT was water-soluble, of which, 32 to 41% was methyl mercury (MeHg) and 59 to 68% was labile inorganic Hg. The concentration of MeHg (range: 0.03 to 1.05 mg kg{sup −1} ww) was positively associated with HgT concentration, and the percent MeHg (4 to 109%) decreased exponentially with increasing HgT concentration in the spinal cord, cerebellum, frontal lobe and temporal lobe. There was a positive association between SeT and HgT in all brain regions (p < 0.05) suggesting that Se may play a role in the detoxification of Hg in the brain. The concentration of HgT in the cerebellum was significantly associated with HgT in other organs. Therefore, HgT concentrations in organs that are frequently sampled in bio-monitoring studies could be used to estimate HgT concentrations in the cerebellum, which is the target organ of MeHg toxicity. - Highlights:

  8. Acoustic development of a neonatal beluga whale (Delphinapterus leucas) at the John G. Shedd Aquarium

    Science.gov (United States)

    Carneiro, Brooke Elizabeth

    Beluga whales (Delphinapterus leucas) were one of the first marine mammals to be in captivity and currently, nine zoological institutions in North America house belugas (Robeck et al., 2005). Despite their accessibility within these facilities, very little research has been done on the beluga whale that is related to their acoustic development or communication sounds. A male beluga calf named "Nunavik" was born at the John G. Shedd Aquarium on 14 December 2009, which provided an opportunity to examine the ontogeny of underwater sounds by a neonatal beluga from the birth throughout the first year of life. The objectives of the study were to: 1) collect underwater sound recordings of the beluga pod prior to the birth of the calf, 2) collect underwater sound recordings of the neonate during the first year of life, 3) document when and what types of sounds were produced by the calf, 4) compare sounds produced by the calf during agonistic and non-agonistic interactions, and 5) compare the acoustic features of sounds produced by the calf to sounds from the mother, a male beluga calf born at the Vancouver Aquarium in 2002, and other belugas at the John G. Shedd Aquarium. The first recordings of the beluga calf took place six hours following the birth for a two hour period. Subsequent recordings were made daily for one hour for the first two weeks of the calf's life and then twice per week until the calf was about six months of age. Later recordings were done less frequently; about once every other week, with no recordings during a 2-month period due to equipment failure. In total, sixty hours of underwater recordings of the belugas were collected from 26 September 2009 to 27 December 2010. Sounds were audibly and visually examined using Raven Pro version 1.4, a real-time sound analysis software application (Cornell Laboratory of Ornithology), and categorized into three categories (tones, noise, and noise with tones) based on the characteristics of underwater sounds from

  9. Selection of reference genes for RT-qPCR studies in blood of beluga whales (Delphinapterus leucas

    Directory of Open Access Journals (Sweden)

    I-Hua Chen

    2016-03-01

    Full Text Available Reverse transcription quantitative PCR (RT-qPCR is used for research in gene expression, and it is vital to choose appropriate housekeeping genes (HKGs as reference genes to obtain correct results. The purpose of this study is to determine stably expressed HKGs in blood of beluga whales (Delphinapterus leucas that can be the appropriate reference genes in relative quantification in gene expression research. Sixty blood samples were taken from four beluga whales. Thirteen candidate HKGs (ACTB, B2M, GAPDH, HPRT1, LDHB, PGK1, RPL4, RPL8, RPL18, RPS9, RPS18, TFRC, YWHAZ were tested using RT-qPCR. The stability values of the HKGs were determined by four different algorithms. Comprehensive analysis of the results revealed that RPL4, PGK1 and ACTB are strongly recommended for use in future RT-qPCR studies in beluga blood samples. This research provides recommendation of reference gene selection, which may contribute to further mRNA relative quantification research in the peripheral blood leukocytes in captive cetaceans. The gene expression assessment of the immune components in blood have the potential to serve as an important approach to evaluating cetacean health influenced by environmental insults.

  10. Adenomatous hyperplasia of the thyroid gland in beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary and Hudson Bay, Quebec, Canada.

    Science.gov (United States)

    Mikaelian, I; Labelle, P; Kopal, M; De Guise, S; Martineau, D

    2003-11-01

    We evaluated thyroid gland lesions in beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary (n = 16) and Hudson Bay (n = 14). Follicular cysts and nodules of adenomatous hyperplasia of the thyroid gland were found in eight and nine adults from the St. Lawrence Estuary (n = 10), respectively, and in four and six adults from Hudson Bay (n = 14), respectively. The total volume of the lesions of thyroid adenomatous hyperplasia was positively correlated with age in both populations. Comparison between populations could not be performed because of differences in age structures of sample groups. Beluga whales from both populations have unique thyroid lesions among marine mammals.

  11. Persistent organochlorines in beluga whales (Delphinapterus leucas) from the St Lawrence River estuary--II. Temporal trends, 1982-1994.

    Science.gov (United States)

    Muir, D C; Koczanski, K; Rosenberg, B; Béland, P

    1996-01-01

    Blubber samples from 16 dead beluga whales (Delphinapterus leucas) collected during 1993-1994 in the St Lawrence River estuary were analysed for PCB congeners and other persistent organochlorines (DDT-group, chlorinated bornanes (toxaphene, CHB), chlordane SigmaCHL), hexachloro-cyclohexanes (SigmaHCH), chlorobenzenes (SigmaCBz), tris(p-chlorophenyl methane (TPMe) and mirex). Concentrations and relative proportions of major individual organochlorine components were within the same range as previous results for this population. Temporal trends were studied by combining the results with data from the analysis of 44 samples (1986-1990) and (for DDT and Aroclor PCBs only) with 20 samples (1982-1985) reported by Martineau et al., 1987. Results were lipid normalized and then age-adjusted by an ANCOVA model. Significant relationships between age and concentrations of most organochlorine groups were found for females but not for males. Significant declines were observed in SigmaDDT, and Aroclor PCBs (1.5- and 1.9-fold, respectively) in males between the 1982-1985 and 1993-1994 collection periods. Significant declines were also observed for SigmaHCH and SigmaCBz in males between 1986-1988 and 1993-1994. Mean concentrations of CHBs were significantly higher in 1993-1994 than in earlier years while dieldrin, SigmaCHL, mirex, and TPMe showed no trend. Declines in concentrations of major organochlorine groups were not observed in females possibly because of higher year to year, and within year, variation. The temporal trend in DDT and PCB concentrations in male beluga blubber paralleled trends in seals, eels, and seabirds in the St Lawrence estuary observed during the 1980s.

  12. Analysis of mitochondrial control region nucleotide sequences from Baffin Bay beluga, (Delphinapterus leucas: detecting pods or sub-populations?

    Directory of Open Access Journals (Sweden)

    Per Jakob Palsbøll

    2002-07-01

    Full Text Available We report the results of an analysis of the variation in the nucleotide sequence of the mitochondrial control region obtained in 218 samples collected from belugas, Delphinapterus leucas, around the Baffin Bay. We detected multiple instances of significant heterogeneity in the distribution of genetic variation among the analyzed mitochondrial control region sequences on a spatial as well as temporal scale indicating a high degree of maternal population structure. The detection of significant levels of heterogeneity between samples collected in different years but within the same area and season was unexpected. Re-examination of earlier results presented by Brown Gladden and coworkers also revealed temporal genetic heterogeneity within the one area where sufficient (n>15 samples were collected in multiple years. These findings suggest that non-random breeding and maternally directed site-fidelity are not the sole causes of genetic heterogeneity among belugas but that a matrilineal pod structure might cause significant levels of genetic heterogeneity as well, even within the same area. We propose that a maternal pod structure, which has been shown to be the cause of significant genetic heterogeneity in other odontocetes, may add to the overall level of heterogeneity in the maternally inherited DNA and hence that much of the spatial heterogeneity observed in this and previous studies might be attributed to pod rather than population structure. Our findings suggest that it is important to estimate the contribution of pod structure to overall heterogeneity before defining populations or management units in order to avoid interpreting heterogeneity due to sampling of different pods as different populations/management units.

  13. Vitamin A and E profiles as biomarkers of PCB exposure in beluga whales (Delphinapterus leucas) from the western Canadian Arctic

    Energy Technology Data Exchange (ETDEWEB)

    Desforges, Jean-Pierre W. [University of Victoria, School of Earth and Ocean Sciences, 3800 Finnerty Road, Victoria, BC, Canada V8P 5C2 (Canada); Fisheries and Oceans Canada, Institute of Ocean Sciences, 9860 West Saanich Road, P.O. Box 6000, Sidney, BC, Canada V8L 4B2 (Canada); Ross, Peter S., E-mail: peter.s.ross@dfo-mpo.gc.ca [University of Victoria, School of Earth and Ocean Sciences, 3800 Finnerty Road, Victoria, BC, Canada V8P 5C2 (Canada); Fisheries and Oceans Canada, Institute of Ocean Sciences, 9860 West Saanich Road, P.O. Box 6000, Sidney, BC, Canada V8L 4B2 (Canada); Dangerfield, Neil [Fisheries and Oceans Canada, Institute of Ocean Sciences, 9860 West Saanich Road, P.O. Box 6000, Sidney, BC, Canada V8L 4B2 (Canada); Palace, Vince P. [Fisheries and Oceans Canada, Freshwater Institute, 501 University Crescent, Winnipeg, MB, Canada R3T 2N6 (Canada); Whiticar, Michael [University of Victoria, School of Earth and Ocean Sciences, 3800 Finnerty Road, Victoria, BC, Canada V8P 5C2 (Canada); Loseto, Lisa L. [Fisheries and Oceans Canada, Freshwater Institute, 501 University Crescent, Winnipeg, MB, Canada R3T 2N6 (Canada)

    2013-10-15

    Highlights: •We examine the influence of biology, ecology and contaminant exposure on vitamin A and E profiles in Arctic beluga whales. •PCBs altered vitamin profiles after accounting for sex, age, condition and feeding ecology. •We propose a toxicity reference value for the disruption of vitamin A and E profiles in beluga of 1.6 mg/kg PCBs. •The use of vitamins as biomarkers of contaminant effects is contingent upon an understanding of wildlife biology. -- Abstract: We evaluated the utility of vitamin A and E profiles as biomarkers of contaminant exposure in beluga whales (Delphinapterus leucas; n = 66) harvested by the Inuvialuit in the Beaufort Sea. Blubber was an important repository for these vitamins, accounting for 76.8 ± 2.6% of the total body store of vitamin A, and 98.5 ± 0.4% of total vitamin E. While the free alcohol form of vitamin A (retinol) appeared highly regulated, the vitamin A esters were influenced by several biological factors including age, body condition and length. Vitamin E concentrations in liver and blubber were related to age, condition, length and feeding ecology, as described δ{sup 15}N and δ{sup 13}C. Despite the influence of these factors, collective results from univariate statistics, best fit multiple regressions, and principal component analysis (PCA) identified polychlorinated biphenyls (PCBs) as important determinants of vitamin concentrations and profiles in beluga tissues. Blubber PCB concentrations best explained variation of the first principal component in a PCA of hepatic vitamins (r{sup 2} = 0.13, p = 0.014), and regression models found that vitamin A concentrations were negatively correlated with PCB levels in liver (esters: r{sup 2} = 0.19, p = 0.001), but positively in plasma (retinol: r{sup 2} = 0.20, p = 0.06) and blubber (retinol: r{sup 2} = 0.22, p = 0.001, esters: r{sup 2} = 0.43, p < 0.001). Our analyses provide a basis to propose an integrated toxicity reference value for disruption of vitamin A and

  14. The limits of applicability of the sound exposure level (SEL) metric to temporal threshold shifts (TTS) in beluga whales, Delphinapterus leucas.

    Science.gov (United States)

    Popov, Vladimir V; Supin, Alexander Ya; Rozhnov, Viatcheslav V; Nechaev, Dmitry I; Sysueva, Evgenia V

    2014-05-15

    The influence of fatiguing sound level and duration on post-exposure temporary threshold shift (TTS) was investigated in two beluga whales (Delphinapterus leucas). The fatiguing sound was half-octave noise with a center frequency of 22.5 kHz. TTS was measured at a test frequency of 32 kHz. Thresholds were measured by recording rhythmic evoked potentials (the envelope following response) to a test series of short (eight cycles) tone pips with a pip rate of 1000 s(-1). TTS increased approximately proportionally to the dB measure of both sound pressure (sound pressure level, SPL) and duration of the fatiguing noise, as a product of these two variables. In particular, when the noise parameters varied in a manner that maintained the product of squared sound pressure and time (sound exposure level, SEL, which is equivalent to the overall noise energy) at a constant level, TTS was not constant. Keeping SEL constant, the highest TTS appeared at an intermediate ratio of SPL to sound duration and decreased at both higher and lower ratios. Multiplication (SPL multiplied by log duration) better described the experimental data than an equal-energy (equal SEL) model. The use of SEL as a sole universal metric may result in an implausible assessment of the impact of a fatiguing sound on hearing thresholds in odontocetes, including under-evaluation of potential risks.

  15. Investigation into the response of the auditory and acoustic communications systems in the Beluga whale (Delphinapterus leucas) of the St. Lawrence River Estuary to noise, using vocal classification

    Science.gov (United States)

    Scheifele, Peter Martin

    2003-06-01

    Noise pollution has only recently become recognized as a potential danger to marine mammals in general, and to the Beluga Whale (Delphinapterus leucas) in particular. These small gregarious Odontocetes make extensive use of sound for social communication and pod cohesion. The St. Lawrence River Estuary is habitat to a small, critically endangered population of about 700 Beluga whales who congregate in four different sites in its upper estuary. The population is believed to be threatened by the stress of high-intensity, low frequency noise. One way to determine whether noise is having an effect on an animal's auditory ability might be to observe a natural and repeatable response of the auditory and vocal systems to varying noise levels. This can be accomplished by observing changes in animal vocalizations in response to auditory feedback. A response such as this observed in humans and some animals is known as the Lombard Vocal Response, which represents a reaction of the auditory system directly manifested by changes in vocalization level. In this research this population of Beluga Whales was tested to determine whether a vocalization-as-a-function-of-noise phenomenon existed by using Hidden Markhov "classified" vocalizations as targets for acoustical analyses. Correlation and regression analyses indicated that the phenomenon does exist and results of a human subjects experiment along with results from other animal species known to exhibit the response strongly implicate the Lombard Vocal Response in the Beluga.

  16. Pathologic Findings and Trends in Mortality in the Beluga (Delphinapterus leucas) Population of the St Lawrence Estuary, Quebec, Canada, From 1983 to 2012.

    Science.gov (United States)

    Lair, S; Measures, L N; Martineau, D

    2016-01-01

    An isolated population of beluga (Delphinapterus leucas) inhabits the St Lawrence Estuary, Quebec, Canada. This population has failed to recover despite the prohibition of hunting >30 years ago, suggesting the presence of other limiting factors. The authors summarize the reported causes of death and propose risk factors to explain the lack of recovery of this population. From 1983 to 2012, a total of 472 beluga were found stranded. Complete necropsies were carried out on 222 beluga, including 178 adults, 25 juveniles, and 19 newborn calves. Infectious diseases, the most prevalent cause of mortality in this population, accounted for the death of one-third of all beluga (32%). Verminous pneumonia was the cause of mortality of 13 juvenile beluga (52% of juvenile beluga). A total of 39 malignant neoplasms, diagnosed in 35 beluga, caused the death of 31 beluga (20% of beluga >19 years old). Median age at diagnosis of cancer was 48 years (range, 30-61 years). Dystocia and postpartum complications were the cause of death in 18 beluga, accounting for 19% of the females >19 years old examined. The occurrence of parturition-associated complications, as well as mortality of calves <1 year old, have increased recently in this population and may be the probable cause of the recent decrease in the size of this population. One of the hypotheses proposed to explain the unusually high occurrence of some of the pathologic conditions observed in this population is chronic exposure to environmental contaminants.

  17. Allelic and haplotype variation of major histocompatibility complex class II DRB1 and DQB loci in the St Lawrence beluga (Delphinapterus leucas).

    Science.gov (United States)

    1999-07-01

    In order to assess levels of major histocompatibility complex (Mhc) variation within the St Lawrence beluga (Delphinapterus leucas) the variation at the beluga Mhc DRB1 class II locus was assessed by single-strand conformation polymorphism (SSCP) analysis of the peptide-binding region for 313 whales collected from 13 sampling locations across North America. In addition, samples from west Greenland and the St Lawrence were also typed at the DQB locus, allowing comparison to a previous study and assessment of linkage disequilibrium of alleles at the two loci. Comparisons of DRB1 and DQB allele frequencies among all sampling locations indicated genetic structure (alpha St Lawrence, Hudson Strait, Bering Sea, Cunningham Inlet, and Davis Strait (minus Cunningham Inlet), except the St Lawrence and Hudson Strait for the DQB locus. In the St Lawrence population, six of the eight DRB1 alleles are present representing all five known allelic lineages. Evidence of linkage disequilibrium between the DRB1 and DQB is present in two sampling locations, the St Lawrence and Nuussuaq (alpha = 0.05). Analysis of probable DRB1-DQB haplotypes among groups of beluga suggests a haplotype reduction in the St Lawrence.

  18. Concentrations and chromatographic profile of DDT metabolites and polychlorobiphenyl (PCB) residues in stranded Beluga Whales (Delphinapterus leucas) from the St. Lawrence Estuary, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Masse, R.; Martineau, D.; Tremblay, L.; Beland, P.

    1986-09-01

    The concentrations and high resolution gas chromatographic profiles of DDT metabolites and polychlorobiphenyl (PCB) congeners were determined in blubber, liver, kidney and lung tissue and milk samples of stranded beluga whales (Delphinapterus leucas) collected at localities along the coasts of the Saint Lawrence Estuary, Canada from November 1983 through December 1984. The analyses indicate that the major PCB components of the tissues were 2,2',5,5'-tetra-, 2,2',4,4',5-penta-, 2,2',3,4,4',5'-hexa-, 2,2',4,4',5,5'-hexa-, 2,2',3,3',4,5-hexa-, 2,3,3',5,5',6-hexa-, 2,2',3,4,5,5',6-hepta- and 2,2',3,4,4',5,5'-heptachlorobiphenyls. Although the highest organochlorine chemical concentrations were found primarily in the blubber, concentrations of 1.72 ..mu..g/g for PCB and 2.04 ..mu..g/g for ..sigma..DDT were determined in one milk sample. No correlation was established between PCB, p,p-DDE and ..sigma..DDT concentrations and the fat content of the kidney, liver and lung tissues. The chromatographic patterns of the PCB congeners were similar from one tissue to another with the exception of the kidney; the profile indicates the retention of PCB congeners which are minor components in the other tissues. Relations of residue concentrations between tissue are described and the significance of congener-specific PCB analysis is discussed in terms of the structure-activity effects on PCB persistence and toxicity.

  19. Population structure of North American beluga whales (Delphinapterus leucas) based on nuclear DNA microsatellite variation and contrasted with the population structure revealed by mitochondrial DNA variation

    Science.gov (United States)

    Gladden; Ferguson; Friesen; Clayton

    1999-03-01

    Beluga whales (Delphinapterus leucas) in North American waters migrate seasonally between wintering areas in broken pack ice and summering locations in estuaries and other open water areas in the Arctic and sub-Arctic. Results from our previous investigation of beluga whale mitochondrial DNA (mtDNA) revealed genetic heterogeneity among beluga from different summering locations that was interpreted as representing a high degree of summering site philopatry. However, mtDNA is maternally inherited and does not reflect mating that may occur among beluga from different summering locations in wintering areas or during annual migrations. To test the possibility that breeding occurs among beluga from different summering locations, genetic variability at five nuclear DNA (nDNA) microsatellite loci was examined in the same animals tested in the mtDNA study. Beluga samples (n = 640) were collected between 1984 and 1994 from 24 sites across North America, mostly during the summer. Whales from the various sites were categorized into eight summering locations as identified by mtDNA analysis, as well as four hypothesized wintering areas: Bering Sea, Hudson Strait (Hudson Strait, Labrador Sea, southwest Davis Strait), Baffin Bay (North Water, east Davis Strait), and St Lawrence River. Microsatellite allele frequencies indicated genetic homogeneity among animals from summering sites believed to winter together but differentiation among whales from some of the wintering areas. In particular, beluga from western North America (Bering Sea) were clearly distinguished from beluga from eastern North America (Hudson Strait, Baffin Bay, and St Lawrence River). Based upon the combined data set, the population of North American beluga whales was divided into two evolutionarily significant units. However, the population may be further subdivided into management units to reflect distinct groups of beluga at summering locations.

  20. PCBs and organochlorine pesticides in blubber biopsies from free-ranging St. Lawrence River Estuary beluga whales (Delphinapterus leucas), 1994-1998

    Energy Technology Data Exchange (ETDEWEB)

    Hobbs, K.E.; Muir, D.C.G.; Michaud, Robert; Beland, Pierre; Letcher, R.J.; Norstrom, R.J

    2003-04-01

    Measuring contaminants only in stranded whales may result in overestimation of organochlorines. - For the first time, organochlorine (OC) contaminants were measured in blubber biopsies from free-ranging St. Lawrence River Estuary beluga whales (Delphinapterus leucas), to compare contaminant levels to those previously measured in dead stranded belugas. PCBs, DDTs, toxaphene and chlordane-related compounds were the major OC contaminants detected in 44 belugas biopsied in 1994-1998. {sigma}PCB (the sum of 104 congeners) ranged from 2080 to 128,000 ng/g lipid in males (n=34; minimum estimated ages 8-22 years), and from 148 to 44,100 ng/g lipid in females (n=10; minimum estimated ages 7-22 years). The concentrations of PCBs and OC pesticides in the blubber of these whales overlapped those observed in stranded belugas from an earlier study, and demonstrated comparable age and sex-related trends. However, lower proportions of mirex, HCB, DDTs, and many of the highly chlorinated PCBs occurred in the biopsy samples compared to results for blubber from stranded carcasses. Most major OC compounds were present at lower concentrations in the biopsies, but this does not appear to be solely related to age differences between the two groups, or to emaciation in the stranded whales. Nor does it appear to be associated with the use of superficial biopsies, and the possible stratification of lipids and OCs in the blubber layer. Nevertheless, given these possible confounding factors, and the uncertainty in age estimates for the biopsied whales, the results point to the need for careful interpretation of biopsy results when comparing with data taken from the full depth of the blubber mantle in stranded whales. Taken together, results from both biopsied whales and previously studied stranded belugas indicate that PCB and OC pesticide contamination of St. Lawrence beluga whales may occur across a broader range of levels than previously thought, at least for males which formed the largest

  1. PCBs and organochlorine pesticides in blubber biopsies from free-ranging St. Lawrence River Estuary beluga whales (Delphinapterus leucas), 1994-1998.

    Science.gov (United States)

    Hobbs, Karen E; Muir, Derek C G; Michaud, Robert; Béland, Pierre; Letcher, Robert J; Norstrom, Ross J

    2003-01-01

    For the first time, organochlorine (OC) contaminants were measured in blubber biopsies from free-ranging St. Lawrence River Estuary beluga whales (Delphinapterus leucas), to compare contaminant levels to those previously measured in dead stranded belugas. PCBs, DDTs, toxaphene and chlordane-related compounds were the major OC contaminants detected in 44 belugas biopsied in 1994-1998. SigmaPCB (the sum of 104 congeners) ranged from 2080 to 128,000 ng/g lipid in males (n=34; minimum estimated ages 8-22 years), and from 148 to 44,100 ng/g lipid in females (n=10; minimum estimated ages 7-22 years). The concentrations of PCBs and OC pesticides in the blubber of these whales overlapped those observed in stranded belugas from an earlier study, and demonstrated comparable age and sex-related trends. However, lower proportions of mirex, HCB, DDTs, and many of the highly chlorinated PCBs occurred in the biopsy samples compared to results for blubber from stranded carcasses. Most major OC compounds were present at lower concentrations in the biopsies, but this does not appear to be solely related to age differences between the two groups, or to emaciation in the stranded whales. Nor does it appear to be associated with the use of superficial biopsies, and the possible stratification of lipids and OCs in the blubber layer. Nevertheless, given these possible confounding factors, and the uncertainty in age estimates for the biopsied whales, the results point to the need for careful interpretation of biopsy results when comparing with data taken from the full depth of the blubber mantle in stranded whales. Taken together, results from both biopsied whales and previously studied stranded belugas indicate that PCB and OC pesticide contamination of St. Lawrence beluga whales may occur across a broader range of levels than previously thought, at least for males which formed the largest group in this study, possibly due to different degrees of dietary exposure. It also appears that

  2. Temporal trends (1987-2002) of persistent, bioaccumulative and toxic (PBT) chemicals in beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary, Canada.

    Science.gov (United States)

    Lebeuf, Michel; Noël, Michelle; Trottier, Steve; Measures, Lena

    2007-09-20

    Temporal trends of persistent, bioaccumulative and toxic (PBT) chemicals were examined in beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary (SLE), Canada. Blubber samples of 86 adult belugas were collected from animals stranded on the shore of the SLE between 1987 and 2002 and analyzed for several regulated PBTs, including polychlorinated biphenyls (PCBs), p,p'dichlorodiphenyltrichloroethane (DDT) and its metabolites, chlordane (CHL) and related compounds, hexachlorocyclohexane (HCH) isomers, hexachlorobenzene (HCB) and Mirex. In addition, time trends of tris(4-chlorophenyl)methane (TCPMe) and tris(4-chlorophenyl)methanol (TCPMOH), two compounds that may origin from DDT formulations, were also examined. Concentrations of most of the PBTs examined had exponentially decreased by at least a factor of two (half-life time (t(1/2))<15 years) in beluga between 1987 and 2002 while no increasing trends were observed for any of the PBTs measured. The decreasing trends of PBT concentrations in SLE beluga may be due to a decline in contamination of its diet following North American and international regulations on the use and production of these compounds or by a change in its diet itself or by a combination of both. Some PBTs did not exhibit any significant trends in beluga possibly because the most intense elimination phase subsequent to legislative regulations occurred prior to the 1987-2002 time period. Other chemicals, such gamma-HCH, did not significantly decrease likely because they are still currently used in some restricted applications. Conversely, alpha-HCH showed a significant decreasing trend indicating that SigmaHCHs is not representative of all HCHs. Both TCPMe and TCPMOH exhibited no trends in beluga during the time period examined. The metabolic capacity of SLE beluga has apparently accelerated the depletion of at least one PBT, namely CB-28/31. A significant relationship between the half-life of PBTs in beluga and log Kow was observed for

  3. Persistent organochlorines in beluga whales (Delphinapterus leucas) from the St Lawrence River estuary--I. Concentrations and patterns of specific PCBs, chlorinated pesticides and polychlorinated dibenzo-p-dioxins and dibenzofurans.

    Science.gov (United States)

    Muir, D C; Ford, C A; Rosenberg, B; Norstrom, R J; Simon, M; Béland, P

    1996-01-01

    Blubber samples from beluga whales (Delphinapterus leucas) in the St Lawrence River estuary were analysed for PCB congeners (ortho- and non-ortho-substituted) and other persistent organochlorines as well as chlorinated dibenzo-dioxins/furans (PCDD/Fs). Major individual components (mean concentrations > 1 microg g(-1)) were 4,4'-DDE, -DDD and -DDT, T12 (a toxaphene-related compound), trans-nonachlor, oxychlordane, mirex, HCB, tris(p-chlorophenyl) methane and dieldrin. Concentrations of SigmaPCBs (8.3-412 microg g(-1)), SigmaDDT (3.36-389 microg g(-1)) and mirex (0.18-6.8 microg g(-1)) were particularly elevated relative to other odontocetes in Canadian waters. SigmaDDT, PCBs (as Aroclor), mirex and T12 concentrations were positively correlated with age of adult females (> 10 years) but only weakly, or not significantly, correlated with age of adult males. PCDD/Fs were present at low ng kg(-1) levels and consisted mainly of penta- and hexachlorofurans, and hepta- and octachlorodioxin. CB126 (3,3',4,4',5-PCB) was the most prominent non-ortho-substituted PCB congener in beluga blubber. Total TCDD toxic equivalents averaged 330 ng kg(-1) in females and 1400 ng kg(-1) in males and were dominated by CB126, and the mono-ortho-substituted congeners CB105 and CB118. Biomagnification factors (BMFs) for mirex and SigmaPCB from fish to beluga ranged from 11 to 16, and were similar to BMFs in Arctic animals, indicating that elevated levels in St Lawrence animals are a consequence of relatively high levels of recalcitrant organochlorines in prey of the beluga in the St Lawrence river system.

  4. Characterization and profiling of hepatic cytochromes P450 and phase II xenobiotic-metabolizing enzymes in beluga whales (Delphinapterus leucas) from the St. Lawrence River Estuary and the Canadian Arctic.

    Science.gov (United States)

    McKinney, Melissa A; Arukwe, Augustine; De Guise, Sylvain; Martineau, Daniel; Béland, Pierre; Dallaire, André; Lair, Stéphane; Lebeuf, Michel; Letcher, Robert J

    2004-07-30

    Cytochromes P450 (CYP, phase I) and conjugating (phase II) enzymes can be induced by and influence the toxicokinetics (metabolism) and toxicity of xenobiotic contaminants in exposed organisms. Beluga whale (Delphinapterus leucas) from the endangered St. Lawrence (SL) River Estuary population exhibit deleterious health effects and various severe pathologies that have been associated with contaminant exposure. In contrast, such effects (e.g. reproductive and immunological impairment) are generally less frequent in less exposed populations in the Canadian Arctic (CA). In the present study, opportunistic sampling resulted in the collection immediately after death of liver tissue from a single female neonate SL beluga (SL6) and male and female CA beluga (n=10) from the Arviat region of western Hudson Bay, in addition to sampling of stranded carcasses of male and female SL beluga (n=5) at least 12 h postmortem. We immunologically characterized cross-reactive proteins of hepatic microsomal CYP1A, CYP2B, CYP3A, CYP2E, epoxide hydrolase (EH) and uridine diphosphoglucuronosyl transferase (UDPGT) isozymes. Cross-reactive proteins were found in all SL and CA beluga using anti-rat CYP1A1, anti-rainbow trout CYP3A, anti-human CYP2E1, anti-rabbit EH and anti-human UDPGT1A1 polyclonal antibodies (Abs), whereas faintly cross-reactive CYP2B proteins were only found in SL6 and the CA samples using an anti-rabbit CYP2B1 Ab. In corresponding catalytic activity assessments, only SL6 and all CA beluga microsomal samples exhibited CYP1A-mediated 7-ethoxyresorufin O-deethylase (EROD) activity (51-260 pmol/mg/min), CYP3A-mediated activity (113-899 pmol/mg/min) based on the formation of 6beta-hydroxytestosterone using a testosterone hydroxylase assay, and UDPGT activity (830-4956 pmol/mg/min) based on 1-naphthylglucuronide formation. The marginal cross-reactivity with the anti-CYP2B1 Ab and lack of catalytically measurable hydroxytestosterone isomers associated with CYP2B-type activity in

  5. Methylsulfone polychlorinated biphenyl and 2,2-bis(chlorophenyl)-1,1-dichloroethylene metabolites in beluga whale (Delphinapterus leucas) from the St. Lawrence River estuary and western Hudson Bay, Canada

    Energy Technology Data Exchange (ETDEWEB)

    Letcher, R.J.; Norstrom, R.J.; Muir, D.C.G.; Sandau, C.D.; Koczanski, K.; Michaud, R.; De Guise, S.; Beland, P.

    2000-05-01

    Knowledge is limited regarding methylsulfone (MeSO{sub 2})-polychlorinated biphenyl (PCB), and especially MeSo{sub 2}-2,2-bis(chlorophenyl)-1,1-dichloroethylene (DDE), metabolites in cetacean species. The authors hypothesized that the ability of beluga whale (Delphinapterus leucas) to biotransform PCB and DDE compounds, and to form and degrade their MeSO{sub 2}-PCB and -DDE metabolites, is related to the capacity for xenobiotic metabolism. Adipose biopsies were collected from male and female beluga whale from distinct populations in the St. Lawrence River estuary (STL) and western Hudson Bay (WHB), Canada, which are contrasted by the exposure to different levels of cytochrome P450 enzyme-inducing, chlorinated hydrocarbon contaminants. The PCBs, DDTs, DDEs, 28 MeSO{sub 2} metabolites of 14 meta-para chlorine-unsubstituted PCBs, and four MeSO{sub 2} metabolites of 4,4{prime}- and 2,4{prime}-DDE were determined. The mean concentrations of total ({Sigma}-) MeSO{sub 2}-PCB in male STL beluga (230 ng/g), and ratios of {Sigma}-MeSO{sub 2}-PCB to {Sigma}-PCB (0.05) and {Sigma}-precursor-PCB (0.17) were approximately twofold higher, whereas the {Sigma}-precursor-PCB to {Sigma}-PCB ratio was approximately twofold lower, than in male WHB beluga. Both populations had a low formation capacity for MeSO{sub 2}-PCBs with {le} six chlorines (<4% of {Sigma}-MeSO{sub 2}-PCBs). The congener patterns were dominated by trichloro- and tetrachloro-MeSO{sub 2}-PCBs, and tetrachloro- and pentachloro-MeSO{sub 2}-PCBs in WHB and STL animals, respectively. In addition to 2- and 3-MeSO{sub 2}-4,4{prime}-DDE, two unknown MeSO{sub 2}-2,4{prime}-DDEs were detected. The mean 3-MeSO{sub 2}-4,4{prime}-DDE concentration in STL beluga (1.2 ng/g) was much greater than in WHB animals. The concentrations of 4,4{prime}-DDE, and not 3-MeSO{sub 2}-4,4{prime}-DDE, increased with age in male STL animals. The authors demonstrated that sulfone formation and clearance is related to metabolic capacity, and thus

  6. Immune functions in beluga whales (Delphinapterus leucas): Evaluation of natural killer cell activity.

    NARCIS (Netherlands)

    S. De Guise (Sylvain); P.S. Ross (Peter); A.D.M.E. Osterhaus (Albert); D. Martineau (Daniel); P. Beland; M. Fournier (Michel)

    1997-01-01

    textabstractNatural killer (NK) activity, an important non-specific defense mechanism against viral infections and tumors, was demonstrated in beluga whales using two different methods: 51Cr release and flow cytometry. Using the 51Cr release assay, NK activity in belugas was shown to be higher again

  7. Beluga (Delphinapterus leucas granulocytes and monocytes display variable responses to in vitro pressure exposures

    Directory of Open Access Journals (Sweden)

    Laura A Thompson

    2015-05-01

    Full Text Available While it is widely known that marine mammals possess adaptations which allow them to make repetitive and extended dives to great depths without suffering ill effects seen in humans, the response of marine mammal immune cells to diving is unknown. Renewed interest in marine mammal dive physiology has arisen due to reports of decompression sickness-like symptoms and embolic damage in stranded and by-caught animals, and there is concern over whether anthropogenic activities can impact marine mammal health by disrupting adaptive dive responses and behavior. This work addresses the need for information concerning marine mammal immune function during diving by evaluating granulocyte and monocyte phagocytosis, and granulocyte activation in belugas (n=4 in comparison with humans (n=4, with and without in vitro pressure exposures. In addition, the potential for additional stressors to impact immune function was investigated by comparing the response of beluga cells to pressure between baseline and stressor conditions. Granulocyte and monocyte phagocytosis, as well as granulocyte activation, were compared between pressure exposed and non-exposed cells for each condition, between different pressure profiles and between conditions using mixed generalized linear models (α=0.05. The effects of pressure varied between species as well by depth, compression/decompression rates, and length of exposures, and condition for belugas. Pressure induced changes in granulocyte and monocyte function in belugas could serve a protective function against dive-related pathologies and differences in the response between humans and belugas could reflect degrees of dive adaptation. The alteration of these responses during physiologically challenging conditions may increase the potential for dive-related in jury and disease in marine mammals.

  8. Transitional Cell Carcinoma of the Urinary Bladder in a Beluga Whale (Delphinapterus leucas).

    Science.gov (United States)

    Martineau, D; Lagacé, A; Massé, R; Morin, M; Béland, P

    1985-10-01

    A transitional cell carcinoma of the urinary bladder was found in a beluga whale stranded in the St. Lawrence middle estuary. Various organs of this animal were submitted to high resolution gas chromatography coupled with mass spectrometry analysis. High frequency of urinary bladder cancer in the human population of the same area and the presence of carcinogenic compounds in the marine environment of this animal are discussed.Concurrent isolation of Edwardsiella tarda from various organs of this whale is also reported.

  9. Immune functions in beluga whales (Delphinapterus leucas): Evaluation of natural killer cell activity.

    OpenAIRE

    Guise, Sylvain De; Ross, Peter; Osterhaus, Albert; Martineau, Daniel; Beland, P; Fournier, Michel

    1997-01-01

    textabstractNatural killer (NK) activity, an important non-specific defense mechanism against viral infections and tumors, was demonstrated in beluga whales using two different methods: 51Cr release and flow cytometry. Using the 51Cr release assay, NK activity in belugas was shown to be higher against K-562 than against YAC-1 cell lines. Moreover, it was enhanced by the addition of human recombinant interleukin-2 with both cell lines. NK activity evaluated by flow cytometry in the peripheral ...

  10. Immune functions in beluga whales (Delphinapterus leucas): Evaluation of natural killer cell activity.

    NARCIS (Netherlands)

    S. De Guise (Sylvain); P.S. Ross (Peter); A.D.M.E. Osterhaus (Albert); D. Martineau (Daniel); P. Beland; M. Fournier (Michel)

    1997-01-01

    textabstractNatural killer (NK) activity, an important non-specific defense mechanism against viral infections and tumors, was demonstrated in beluga whales using two different methods: 51Cr release and flow cytometry. Using the 51Cr release assay, NK activity in belugas was shown to be higher again

  11. Transitional Cell Carcinoma of the Urinary Bladder in a Beluga Whale (Delphinapterus leucas)

    OpenAIRE

    Martineau, D.; Lagacé, A.; Massé, R; Morin, M.; Béland, P

    1985-01-01

    A transitional cell carcinoma of the urinary bladder was found in a beluga whale stranded in the St. Lawrence middle estuary. Various organs of this animal were submitted to high resolution gas chromatography coupled with mass spectrometry analysis. High frequency of urinary bladder cancer in the human population of the same area and the presence of carcinogenic compounds in the marine environment of this animal are discussed.

  12. Immune functions in beluga whales (Delphinapterus leucas): evaluation of natural killer cell activity.

    Science.gov (United States)

    De Guise, S; Ross, P S; Osterhaus, A D; Martineau, D; Béland, P; Fournier, M

    1997-09-19

    Natural killer (NK) activity, an important non-specific defense mechanism against viral infections and tumors, was demonstrated in beluga whales using two different methods: 51Cr release and flow cytometry. Using the 51Cr release assay, NK activity in belugas was shown to be higher against K-562 than against YAC-1 cell lines. Moreover, it was enhanced by the addition of human recombinant interleukin-2 with both cell lines. NK activity evaluated by flow cytometry in the peripheral blood of eight belugas increased when the effector:target cell (E:T) ratio increased, and averaged 13.9% +/- 3.8% (range 9.9% to 17.8%) at an E:T ratio of 100:1. While NK activity could be readily detected using both methods, the lack of radio-isotopes and related laboratory room make the flow cytometric method a viable and safe alternative. The evaluation of this function in cetaceans could lead to a better understanding of the early events that lead to viral epizootics in populations of marine mammals in different parts of the world, as well as to the high prevalence of neoplasms in St. Lawrence beluga whales.

  13. Beluga (Delphinapterus leucas) granulocytes and monocytes display variable responses to in vitro pressure exposures.

    Science.gov (United States)

    Thompson, Laura A; Romano, Tracy A

    2015-01-01

    While it is widely known that marine mammals possess adaptations which allow them to make repetitive and extended dives to great depths without suffering ill effects seen in humans, the response of marine mammal immune cells to diving is unknown. Renewed interest in marine mammal dive physiology has arisen due to reports of decompression sickness-like symptoms and embolic damage in stranded and by-caught animals, and there is concern over whether anthropogenic activities can impact marine mammal health by disrupting adaptive dive responses and behavior. This work addresses the need for information concerning marine mammal immune function during diving by evaluating granulocyte and monocyte phagocytosis, and granulocyte activation in belugas (n = 4) in comparison with humans (n = 4), with and without in vitro pressure exposures. In addition, the potential for additional stressors to impact immune function was investigated by comparing the response of beluga cells to pressure between baseline and stressor conditions. Granulocyte and monocyte phagocytosis, as well as granulocyte activation, were compared between pressure exposed and non-exposed cells for each condition, between different pressure profiles and between conditions using mixed generalized linear models (α = 0.05). The effects of pressure varied between species as well by depth, compression/decompression rates, and length of exposures, and condition for belugas. Pressure induced changes in granulocyte and monocyte function in belugas could serve a protective function against dive-related pathologies and differences in the response between humans and belugas could reflect degrees of dive adaptation. The alteration of these responses during physiologically challenging conditions may increase the potential for dive-related in jury and disease in marine mammals.

  14. Age and sex distributions in the catches of belugas, Delphinapterus leucas , in West Greenland and in western Russia

    DEFF Research Database (Denmark)

    Heide-Jørgensen, M.P.; Lockyer, C.

    2001-01-01

    with mature females were taken. Age was estimated from Growth Layer Groups (GLGs) in sectioned teeth, assuming the currently accepted criteria of 2 GLGs forming annually. The mean and median ages were increasing slightly in both sexes from Upernavik from 1985 through 1994. Both immature and mature whales were...... taken on the wintering grounds from Disko Bay and south. Estimation of survival was confounded by the large number of whales where only a minimum age could be assigned because of tooth wear at the crown (i. e. no neonatal Line in the dentine). The apparent survival rates for belugas from West Greenland...

  15. Groups of related belugas (Delphinapterus leucas) travel together during their seasonal migrations in and around Hudson Bay.

    Science.gov (United States)

    Colbeck, Gabriel J; Duchesne, Pierre; Postma, Lianne D; Lesage, Véronique; Hammill, Mike O; Turgeon, Julie

    2013-02-07

    Social structure involving long-term associations with relatives should facilitate the learning of complex behaviours such as long-distance migration. In and around Hudson Bay (Canada), three stocks of beluga whales form a panmictic unit, but have different migratory behaviours associated with different summering areas. We analysed genetic variation at 13 microsatellite loci among 1524 belugas, to test hypotheses about social structure in belugas. We found significant proportions of mother-offspring pairs throughout the migratory cycle, but average relatedness extended beyond close kinship only during migration. Average relatedness was significantly above random expectations for pairs caught at the same site but on different days or months of a year, suggesting that belugas maintain associations with a network of relatives during migration. Pairs involving a female (female-female or male-female) were on average more related than pairs of males, and males seemed to disperse from their matrilineal group to associate with other mature males. Altogether, our results indicate that relatives other than strictly parents, and especially females, play a role in maintaining a social structure that could facilitate the learning of migration routes. Cultural conservatism may limit contributions from nearby summer stocks to endangered stocks such as the Eastern Hudson Bay beluga.

  16. Pathology of stranded beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary, Québec, Canada.

    Science.gov (United States)

    Martineau, D; Lagacé, A; Béland, P; Higgins, R; Armstrong, D; Shugart, L R

    1988-04-01

    From June 1983 to May 1986, thirteen carcasses of stranded beluga whales from a polluted area of the St. Lawrence River, Canada were necropsied. High performance liquid chromatography was performed on the brains of three other animals to determine concentrations of benzo a pyrene (BaP). Two juvenile animals had severe multisystemic lesions one of which, a severe necrotizing dermatitis, was associated with a Herpesvirus-like particle. Four adults had five varieties of tumours. An adult had a systemic nocardiosis and a juvenile was affected ty a non 0:1 Vibrio cholerae septicemia. High concentrations of BaP adducts were found in the brains which were analyzed. Occurrence of BaP adducts in the brain of three whales of this population coincides with the high incidence of tumours. This and the previous finding of high concentrations of organochlorine in the tissues of these animals suggest an important role of industrial contaminants in the recent decrease of this population.

  17. Non-neoplastic lesions in beluga whales (Delphinapterus leucas) and other marine mammals from the St Lawrence Estuary.

    Science.gov (United States)

    De Guise, S; Lagacé, A; Béland, P; Girard, C; Higgins, R

    1995-04-01

    In a 3-year (1988-1990) pathological study, 24 carcasses of beluga whales from the St Lawrence Estuary, Québec, Canada, showed numerous severe lesions, many of which had never been reported in cetaceans. The most common lesions were found in the digestive tract (21 animals) and consisted mainly of periodontitis and of erosions and ulcers in the oesophagus and the first two gastric compartments. Pneumonia, usually of parasitic origin, was also a common finding (12 animals). The adrenal glands often contained nodules (five animals) or cysts (seven animals), and mastitis was observed in five females. Overall, the incidence of degenerative, infectious, hyperplastic or necrotic lesions, in addition to numerous neoplasms described in another paper, was considerably higher than that found in marine mammals elsewhere or in other species of marine mammal from the same waters.

  18. Lactational Transfer of Polychlorinated-Biphenyls (PCBs) and Other Organochlorines in St. Lawrence Beluga Whales (Delphinapterus leucas).

    Science.gov (United States)

    Cadieux, Marc A; Muir, Derek C G; Béland, Pierre; Hickie, Brendan E

    2016-01-01

    This study uses an individual-based contaminant bioaccumulation model for marine mammals to explore factors controlling the transfer of PCBs from mother to calf via nursing in beluga from the St. Lawrence Estuary. Beluga blubber samples (n = 46), along with four matched milk samples from stranded animals over the 1986-1994 period were used for comparison with modelled results. Based on 68 POPs, including 48 PCBs and 20 other organochlorine compounds, milk:blubber ratios were 0.65 between log K OW 3-6.5, then decreased to 0.1 at log K OW 8. Model simulations based on this relationship indicated females were transferring PCBs that were relatively very hydrophobic and highly chlorinated less readily than their lower chlorinated counterparts, resulting in an enriched concentration of very hydrophobic congeners in nursing females relative to adult males. There was very good agreement between observed and modelled male:female PCB concentration ratios. Four females within our dataset (15 %) had male-like ΣPCB concentrations as well as male-like congener profiles, suggesting that these individuals may have had a reduced or limited nursing history.

  19. Toxoplasmosis in beluga whales (Delphinapterus leucas) from the St Lawrence estuary: two case reports and a serological survey.

    Science.gov (United States)

    Mikaelian, I; Boisclair, J; Dubey, J P; Kennedy, S; Martineau, D

    2000-01-01

    Toxoplasmosis was diagnosed in two free-ranging beluga whales from the St Lawrence estuary, Quebec, Canada, in 1988 and 1998. Histologically, tachyzoites and bradyzoites were present in the brain, spleen, lymph nodes, adrenals and lungs of both animals, and in the thymus of one. These organisms were readily labelled by an indirect immunohistochemical method for Toxoplasma gondii antigens. In the lymph nodes, spleen and lungs the organisms were associated with histiocytic infiltration. In the brain of one animal they were associated with mild multifocal gliosis and haemorrhages. There was no evidence of concomitant morbillivirus infection. Serum samples were collected from 22 beluga whales stranded between 1995 and 1998 on the shores of the St Lawrence Estuary and examined for antibodies to T. gondii by the modified agglutination test. Antibody titres of s25 were found in six (27%) of the animals. This is the first confirmed report of toxoplasmosis in beluga whales.

  20. Immune functions in the Fisher rat fed beluga whale (Delphinapterus leucas) blubber from the contaminated St. Lawrence estuary

    Energy Technology Data Exchange (ETDEWEB)

    Lapierre, P.; Guise, S. De [Univ. du Quebec, Montreal, Quebec (Canada). Dept. des Sciences Biologiques; Muir, D.C.G. [Freshwater Inst., Winnipeg, Manitoba (Canada); Norstrom, R. [Environment Canada, Hull, Quebec (Canada); Beland, P. [St. Lawrence National Inst. of Ecotoxicology, Montreal, Quebec (Canada); Fournier, M. [Univ. du Quebec, Montreal, Quebec (Canada). Dept. des Sciences Biologiques]|[INRS-Sante, Pointe-Claire, Quebec (Canada)]|[IML, Mont Joli, Quebec (Canada). Dept. of Fisheries and Oceans

    1999-02-01

    In order to assess the immunotoxic potential of food naturally contaminated with PCBs and other organohalogens, Fisher rats were fed a diet in which the lipids originated from the blubber of either a highly polluted St. Lawrence beluga or a relatively uncontaminated Arctic beluga. After a period of 2 months, different immune functions were evaluated, including lymphoblastic transformation, natural killer cell activity, plaque-forming cells, phagocytosis, oxidative burst, and immunophenotyping. For all assays, rats fed at St. Lawrence beluga blubber diet or a mixture of Arctic and St. Lawrence beluga blubber diet were not different from control rats fed a diet containing Arctic beluga blubber. These results are inconsistent with the well-known immunosuppressive effects of organochlorines in numerous species and with the lesions suggestive of organochlorine-related immunosuppression that are observed in St. Lawrence belugas. The lack of observable immunotoxic effects in rats fed contaminated beluga blubber might be explained by antagonistic effects in the organohalogen mixture, by a response specific to the rat, by a strain-related lack of sensitivity to organochlorines, or by insufficient dose due to the shortness of the exposure period or the route of exposure.

  1. Immune functions in beluga whales (Delphinapterus leucas): evaluation of phagocytosis and respiratory burst with peripheral blood leukocytes using flow cytometry.

    Science.gov (United States)

    de Guise, S; Flipo, D; Boehm, J R; Martineau, D; Béland, P; Fournier, M

    1995-08-01

    Flow cytometric assays using peripheral blood were developed to study phagocytosis and respiratory burst, the two major functions of neutrophils and among the most important non-specific defense mechanisms, in beluga whales. The use of flow cytometry avoids the problems associated with the isolation and purification of different cell types, and allows the measurement of a large number of cells (10,000) in a very short period of time. The methods described will be used to compare these functions in blood samples from highly contaminated beluga whales from the St. Lawrence and from relatively clean arctic beluga whales.

  2. Pressure Induced Changes in Adaptive Immune Function in Belugas (Delphinapterus leucas; implications for dive physiology and health

    Directory of Open Access Journals (Sweden)

    Laura A Thompson

    2016-09-01

    Full Text Available Increased pressure, associated with diving, can alter cell function through several mechanisms and has been shown to impact immune functions performed by peripheral blood mononuclear cells (PBMC in humans. While marine mammals possess specific adaptations which protect them from dive related injury, it is unknown how their immune system is adapted to the challenges associated with diving. The purpose of this study was to measure PBMC activation (IL2R expression and Concanavalin A induced lymphocyte proliferation (BrdU incorporation in belugas following in vitro pressure exposures during baseline, Out of Water Examination (OWE and capture/release conditions. Beluga blood samples (n=4 were obtained from animals at the Mystic Aquarium and from free ranging animals in Alaska (n=9. Human blood samples (n=4 (Biological Specialty Corporation were run for comparison. In vivo catecholamines and cortisol were measured in belugas to characterize the neuroendocrine response. Comparison of cellular responses between controls and pressure exposed cells, between conditions in belugas, between belugas and humans as well as between dive profiles, were run using mixed generalized linear models (α=0.05. Cortisol was significantly higher in wild belugas and OWE samples as compared with baseline for aquarium animals. Both IL2R expression and proliferation displayed significant pressure induced changes, and these responses varied between conditions in belugas. Both belugas and humans displayed increased IL2R expression, while lymphocyte proliferation decreased for aquarium animals and increased for humans and wild belugas. Results suggest beluga PBMC function is altered during diving and changes may represent dive adaptation as the response differs from humans, a non-dive adapted mammal. In addition, characteristics of a dive (i.e., duration, depth as well as neuroendocrine activity can alter the response of beluga cells, potentially impacting the ability of animals to fight infection or avoid dive related pathologies.

  3. Bowhead (Balaena mysticetus) and beluga (Delphinapterus leucas) whales in the Bering, Chukchi and Beaufort Seas: Annual report

    Data.gov (United States)

    US Fish and Wildlife Service, Department of the Interior — Reproductive activity in the bowhead whale was observed in early May near Pt. Barrow Alaska, indicating that this species may calf and breed during the northward...

  4. Anti-microbial activity of Leucas clarkei

    Directory of Open Access Journals (Sweden)

    Surya Narayan Das

    2012-06-01

    Full Text Available The antimicrobial potency of the whole plant of Leucas clarkei have been studied using the soxhlet extracts of petroleum ether, benzene, chloroform and ethanol extract against Gram-positive bacteria (two strains, Gram-negative bacteria (two strains and two fungi strains by disc diffusion method. Micro-dilution methods, for the determination of minimal inhibition concentration (MIC and the minimal bactericidal and fungicidal concentration (MBC, MFC. The ethanol extract at a concentration of 30 to 60 µg/disc and chloroform extract at a concentration 60 µg/disc showed significant activity against all the bacteria and fungus. All the extracts of L. clarkei have got moderate action but chloroform and ethanol extracts have got significant activity against Candida krusei, Candida albicans, Escherichia coli, Salmonella typhi, Staphylococcus aureus, and Bacillus subtilis. This may be due to phytochemicals such as phytosterols, alkaloid, tannins, phenolic compounds and flavonoids present in the extracts.

  5. Antioxidant, free radical scavenging and invitro cytotoxic studies of ethanolic extract of Leucas indica var lavandulifolia and Leucas indica var nagalapuramiana

    Institute of Scientific and Technical Information of China (English)

    Ramalingam Ramani; Sushruthi Sudini; Bindu Madhavi Boddupalli; Ravinder Nath Anisetti

    2012-01-01

    Objective: The main focus of the study is to determine antioxidant, free radical scavenging and cytotoxic effect of ethanolic extract of whole plant of Leucas indica var lavandulifolia and Leucas indica var nagalapuramiana using various in vitro assay methods as well as to estimate the amount of total phenol and flavonoid contents. Methods: Leucas indica var lavandulifolia and Leucas indica var nagalapuramiana were collected in February 2008 from Thirumala hills and standard procedure from the literature were used to estimate the antioxidant and free radical scavenging activity. Results: The results suggest that both the extracts can be considered as a valuable source of antioxidants products as the obtained values are more or less near to the used standard compound. Conclusions: The characterization of leucas for antioxidant and free radical scavenging activities are new to literature in this context this extensive in vitro study of the selected two species of leucas for antioxidant activity will be a valuable study for further in vivo activities.

  6. Ampullary organs and electroreception in freshwater Carcharhinus leucas.

    Science.gov (United States)

    Whitehead, Darryl L

    2002-01-01

    The ampulla of Lorenzini of juvenile Carcharhlinus leucas differ histologically from those previously described for other elasmobranchs. The wall of the ampullary canal consists of protruding hillock-shaped epidermal cells that appear to secrete large quantities of a mucopolysaccharide gel. The ampullary organs comprise a long canal sheathed in collagen terminating in an ampulla. Each ampulla contains six alveolar sacs, with each sac containing hundreds of receptor cells. The receptor cells are characteristic of others described for elasmobranchs being pear-shaped cells with a central nucleus and bearing a single kinocilium in the exposed apical region of the cell. The supportive cells differ from general elasmobranch ampullary histology in that some have an apical nucleus. These ampullary structures allow Carcharhinus leucas to detect and respond to artificial electrical fields. Carcharhinus leucas from freshwater habitats respond to electrical signals supplied in freshwater aquaria by abruptly turning towards low voltage stimuli (< or = 10 microA) and either swimming over or biting at the origin of the stimulus.

  7. Micro Chemical (Elemental Analysis of Leucas aspera (Willd Link Employing SEM-EDAX

    Directory of Open Access Journals (Sweden)

    Sunkara Yashvanth

    2013-01-01

    Full Text Available The plant, Leucas aspera (Willd Link is well known for its varied medicinal uses. Present study deals with its micro chemical (elemental characterization using Energy Dispersive X-ray Analysis (EDAX detector fitted to Scanning Electron Microscope. The plant has very interesting morphology. Crystals of varied shape and inclusions/exudates were noticed within and on the leaf & stem surfaces. Various plant parts analysed were, stem surface, stem sections, stem inclusions, blebs on stem hairs, crystals of varied shape, root sections, abaxial and adaxial surfaces, flower, seed and seed caruncle. Lot of variation in elemental composition was observed in various plant parts. Major elements detected were Carbon, Oxygen, Calcium, Silica, and Aluminum. Other elements found were Iron, Sodium, potassium, Phosphorus and Chlorine.

  8. PHYTOCHEMISTRY AND PHARMACOLOGICAL ASPECTS OF LEUCAS URTICIFOLIA (VAHL BENTH

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    KALSOOM AKHTAR, SHER BAHADAR KHAN ABDUL MALIK

    2013-09-01

    Full Text Available Medicinal plants have attracted increased attention because of their beneficial effects on human health. Many medicinal plants are used as traditional medicine in various countries for long time. A large number of secondary metabolites with various biological activities have been discovered from various medicinal plants and some bioactive substances derived from plants have diverse functional roles as secondary metabolites and these properties can be applied to the developments of novel pharmaceuticals. Leucas Urticifolia (family- Lamiaceae is an annual herbaceous plant and has various activities. Chemical studies have underlined the presence of various classes of compounds, the main being triterpenes, diterpene, flavonoids and fatty acids. The extract of this plant as well as pure compounds isolated from this plant, have been demonstrated to posses multiple pharmacological activities. In this review, we have explored the phytochemistry and pharmacological activites of Leucas Urticifolia in order to collate existing information on this plant as well as highlight its multi-activity properties as a medicinal agent.

  9. Detection and quantitation of benzo(a)pyrene-DNA adducts in brain and liver tissues of Beluga whales (Delphinapterus leucas) from the St. Lawrence and Mackenzie Estuaries

    Energy Technology Data Exchange (ETDEWEB)

    Shugart, L.R.

    1988-01-01

    It should be noted that there are few analytical techniques available for the detection and quantitation of chemical adducts in the DNA of living organisms. The reasons for this are: the analytical technique often has to accommodate the unique chemical and/or physical properties of the individual chemical or its metabolite; the percentage of total chemical that becomes most of the parent compound is usually detoxified and excreted; not all adducts that form between the genotoxic agent and DNA are stable or are involved in the development of subsequent deleterious events in the organism; and the amount of DNA available for analysis is often quite limited. 16 refs., 1 tab.

  10. Occurrence of chlorinated paraffins in beluga whales (Delphinapterus leucas) from the St. Lawrence River and rainbow trout (Oncorhynchus mykiss) and carp (Cyprinus carpio) from Lake Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Bennie, D. T.; Sullivan, C. A.; Maguire, R. J. [Envirronment Canada, National Water Research Institute, Burlington, ON (Canada)

    2000-07-01

    Samples of 25 dead beluga whales from the St. Lawrence River estuary, as well as samples of 10 rainbow trout and three carps caught in western Lake Ontario were analyzed for total short and medium chain chlorinated paraffins using gas chromatography-low resolution negative chemical ionization spectroscopy. Both short and medium-chain chlorinated paraffins were quantitatively identified in all samples using two commercial preparations. Beluga results were found to be higher than concentrations reported for marine mammals in Europe, but comparable to total PCB and total DDT results for the same population of beluga whales. Results for freshwater species are comparable to those reported for fish sampled from other industrially impacted waterways in North America, but elevated compared to marine species from European studies. Comparisons of the results with gas chromatography-negative ion mass spectroscopy analysis from another study indicated that the two analytical techniques are not congruent. The differences may be accounted for by different effects of interfering organochlorine substances on the analysis of chlorinated paraffins. 22 refs., 5 tabs., 1 fig.

  11. A modelling-based perspective on the past, present, and future polychlorinated biphenyl contamination of the St. Lawrence beluga whale (Delphinapterus leucas) population

    Energy Technology Data Exchange (ETDEWEB)

    Hickie, B. E.; Mackay, D. [Trent Univ., Environmental Modelling Centre, Peterborough, ON (Canada); Kingsley, M. C. S. [Dept. of Fisheries and Oceans, Maurice Lamontagne Institute, Mont Joli, PQ (Canada); Hodson, P. V. [Queen' s Univ., School of Environmental Studies, Kingston, ON (Canada); Muir, D. C. G. [Environment Canada, National Water Resesarch Institute, Burlington, ON (Canada); Beland, P. [St. Lawrence National Inst of Exotoxicology, Montreal, PQ (Canada)

    2000-07-01

    Two models showing the accumulation of polychlorinated biphenyl (PCB) by the St. Lawrence beluga whale population from 1950 to the present are described. The study also aimed at predicting future trends based on likely contaminant loading scenarios. The individual-based model (IB) calculates the accumulation of PCBs over the life time of an individual, taking into account the animal's complete life history, including growth, body composition, energetics, diet, gestation, birth and lactation. The population-based (PB) model is based on energy and contaminant flux budgets summarized from the IB model; it quantifies the changes in contaminant levels throughout the population over several generations. The study also includes consideration of the hypothesis that migrating American eels from Lake Ontario are a significant dietary source of contaminants for the beluga whales in the St. Lawrence River. Results showed that eels may have contributed as much as 45 per cent of the total PCB burden in the population in the mid-1980s. With migrating eels included as part of the beluga diet, PCB concentrations in the population peaked between 1965 and 1975, and have been gradually declining since then. Future declines in PCB levels in the beluga are predicted in proportion with changes in the PCB levels of their prey. This and similar studies are also considered useful in identifying tolerable concentrations of PCBs and other contaminants, information that could be used as tools in aquatic ecosystem management. 52 refs., 8 figs.

  12. PBDEs and PCBs in the liver of the St Lawrence Estuary beluga (Delphinapterus leucas): a comparison of levels and temporal trends with the blubber.

    Science.gov (United States)

    Raach, Meriem; Lebeuf, Michel; Pelletier, Emilien

    2011-03-01

    Due to their lipophilic properties, persistent organic pollutants (POPs) are commonly assessed using the blubber of marine mammals. However, these chemicals are also accumulating in other tissues including the liver. Some pollutants, namely perfluorinated alkyl acids, are found predominately in the liver and blood of marine mammals, and thus monitored in those tissues. This raises the question whether any tissue would represent an identical trend of POPs in the SLE beluga. The current study reports the first temporal trends of PBDEs and PCBs in the liver of 65 SLE belugas. Neither ∑₇PBDEs nor major individual PBDE-homolog group concentrations showed significant trends between 1993 and 2007. Also, ∑₃₂PCBs did not change over years, although, tetra-, penta- and hepta-PCB decreased by 7.1, 6.8 and 8.5%, respectively, in males, whereas tetra-, penta- and octa-PCBs declined by 11, 12 and 12.9%, respectively, in females. In order to compare the distribution of POPs between liver and blubber, a lipid normalised concentration ratio R (blubber/liver) for PBDEs and PCBs was calculated for each individual beluga. For all PBDE and several PCB homolog groups, mean R values were not statistically different from unity indicating that the partitioning of these POPs is governed by the tissue lipid-content. Temporal trends of R ratios of PBDEs and PCBs were also examined. There were generally no significant temporal trends except for PBDEs in males where R increased in average by 12.7 ± 2.9% yearly. The stratification of the blubber into a metabolically active (inner) and less active layers (outer blubber) may result in a slower response time of the blubber (full depth) than the liver to the recent change of contamination in the environment and explain the time trend differences between both tissues. This study suggests that the liver is more representative of recent exposure to lipophilic contaminants.

  13. Anti-bacterial activity of the methanolic extract of leucas hyssopifolia (Benth.

    Directory of Open Access Journals (Sweden)

    Devendra Mishra

    2013-01-01

    Full Text Available Context: Methanolic extract of Leucas hyssopifolia roots was investigated for its anti-bacterial property. Aim: Evaluation of anti-bacterial activity of Leucas hyssopifolia Benth. Settings and Design: Roots of the plant were collected, extracted and finally evaluated for their anti-bacterial activity. Materials and Methods: Paper disc diffusion method and microdilution technique were employed for the determination of zone of inhibition and minimal inhibitory concentration, respectively. Results: The extract showed anti-bacterial activity against all the tested bacterial strains except Escherichia coli. Conclusions: Anti-bacterial activity of extract of Leucas hyssopifolia roots may be due to the presence of secondary plant metabolites like terpenoids, steroids and flavonoids, which are present in the extract. The extract can be further studied for the isolation of chemical compounds and their biological activity.

  14. Central nervous system activity of Leucas inflata Benth. in mice.

    Science.gov (United States)

    Al-Yousuf, M H; Ali, B H; Bashir, A K; Tanira, M O M; Blunden, G

    2002-09-01

    The analgesic activity of the methanol and acetone extracts of Leucas inflata L. (family Labiatae) was evaluated in mice using different experimental models. The effect of the two extracts on pentobarbitone-sleeping time, motor activity, sensorimotor coordination, carrageen induced inflammation, and brewer's yeast-induced pyrexia has also been investigated. The two crude extracts have been phytochemically analyzed and some constituents isolated and characterized. These included stigmasterols, a chromone and coumarins. Extracts of L. inflata L., given at single oral doses of 0.25, 0.5, 1.0 or 2.0 g/kg, significantly and dose-dependently, reduced formalin-induced pain, acetic acid induced abdominal constrictions and increased the reaction time in the hot-plate test. Both extracts caused significant and dose-related impairment in the sensorimotor control and ambulatory and total motor activity of treated mice. Both extracts exhibited anti-inflammatory action by reducing paw edema of treated mice. The extracts did not significantly affect the rectal temperature of normothermic mice. However, they were effective in preventing Brewers yeast induced pyrexia. It is concluded that the crude methanol and acetone extract of L. inflata has CNS depressant properties, manifested as antinociception and sedation. Both extracts have anti-inflammatory and antipyretic actions.

  15. Antioxidant and antibacterial activity of different parts of Leucas aspera

    Institute of Scientific and Technical Information of China (English)

    Ai Lan Chew; Jeyanthi James Antony Jessica; Sreenivasan Sasidharan

    2012-01-01

    Objective: To evaluate antioxidant, antimicrobial and cytotoxic activity of different parts (root, flower, leaf and stem) of Leucas aspera (L. aspera) (Labiatae). Methods: Different parts of L. aspera were extracted with 80% (v/v) methanol. The methanol extracts were subjected to antioxidant, antimicrobial and brine shrimp lethality assay. Results: All the extracts showed moderate to potent antioxidant activity, among which the root extract demonstrated the strongest antioxidant activity with the IC50 value of 6.552 μg/mL. Methanol extract of root possessed antioxidant activity near the range of vitamin E and thus could be a potential rich source of natural antioxidant. In case of antimicrobial screening, crude extracts of root, flower, leaf and stem showed notable antibacterial activity against tested microorganisms. The root extract showed the highest mean zone of inhibition ranging from 9.0-11.0 mm against tested microorganisms, at a concentration of 100 mg/mL. In the brine shrimp lethality bioassay, it was evident that the methanol root extract did not show significant toxicity. The LC50 value for 12 h and 24 h observation was 2.890 mg/mL and 1.417 mg/mL, respectively. Conclusions: The present finding suggests that the methanol root extract of L. aspera could be developed as pharmaceutical products.

  16. Phytochemical and antibacterial studies on Leucas vestita Wall ex Benth

    Institute of Scientific and Technical Information of China (English)

    Salem Varadharajan Rajesh; Thiruppathi Senthil Kumar; Mandali Venkateswara Rao

    2012-01-01

    Objective: In search of alternative herbal medicine for pathogenic microorganism variety of plant species have been identified. However, search of new species are still in progress to reduce the pressure on biological diversity and increase availability of organic compound. In the light of this the present work identified phytochemical property and antibacterial activity of Leucas vestita.Methods:The ethanol extract of L. vestita was used for this study. The phytochemicals present in the extract was identified and the antibacterial activity was tested through disc diffusion method. Results: The phytochemical studies revealed the presence of primary and secondary metabolites which ensuring their herbal properties. Antimicrobial activity showed increasing zone of inhibition with increasing concentration of the extract with Staphylococcus aureus, Bacillus subtilis, Enterobacter aerogenes, Klebsiella pneumoniae and Proteus mirabilis among the other microorganism. Larger zone of inhibition of 14mm was recorded for K. pneumoniae. Conclusions:The study suggests that this extract can be used as a medicine to control some of these pathogenic bacteria.

  17. Mechanism of antibacterial action of the alcoholic extracts of Hemidesmus indicus (L.) R. Br. ex Schult, Leucas aspera (Wild.), Plumbago zeylanica L., and Tridax procumbens (L.) R. Br. ex Schult.

    Science.gov (United States)

    Saritha, Kongari; Rajesh, Angireddy; Manjulatha, Khanapur; Setty, Oruganti H; Yenugu, Suresh

    2015-01-01

    Herbal products derived from Hemidesmus indicus (L.) R. Br. ex Schult, Leucas aspera (Wild.), Plumbago zeylanica L., and Tridax procumbens (L.) R. Br. ex Schult. are widely used in traditional medicine. Though the extracts of these plants were found to be antimicrobial in nature and have the potential to be used in clinics, the mechanism of action of is not reported. The ethanolic extracts of Hemidesmus indicus (L.) R. Br. ex Schult, Hemidesmus indicus ethanolic extract (HIEE), Leucas aspera (Wild.), Leucas aspera ethanolic extract (LAEE), Plumbago zeylanica L., Plumbago zeylanica ethanolic extract (PZEE), and Tridax procumbens (L.) R. Br. ex Schult, Tridax procumbens ethanolic extract (TPEE) were tested for their antibacterial activity against E. coli. Antibacterial activity was analyzed by CFU assay and the effect on the bacterial membrane by fluorescence activated cell sorting and scanning electron microscopy. LAEE, PZEE, and HIEE displayed potent bacterial killing activity in a time and concentration dependent manner. TPEE did not display appreciable antibacterial activity. The antibacterial action involved disruption of membrane potential, inner membrane permeabilization, blebbing and leakage of cellular contents. Our results contribute to the understanding of the antibacterial mechanism of alcoholic extracts of the medicinal plants used in this study.

  18. To Madagascar and back: long-distance, return migration across open ocean by a pregnant female bull shark Carcharhinus leucas.

    Science.gov (United States)

    Lea, J S E; Humphries, N E; Clarke, C R; Sims, D W

    2015-12-01

    A large, pregnant, female bull shark Carcharhinus leucas was tracked migrating from Seychelles across open ocean to south-east Madagascar, c. 2000 km away, and back again. In Madagascar, the shark spent a prolonged period shallower than 5 m, consistent with entering estuarine habitat to pup, and upon return to Seychelles the shark was slender and no longer gravid. This represents an unprecedented return migration across the open ocean for a C. leucas and highlights the need for international collaboration to manage the regional C. leucas population sustainably.

  19. Synthesis of Leucas Aspera Extract Loaded Gold-PLA-PEG-PLA Amphiphilic Copolymer Nanoconjugates: In Vitro Cytotoxicity and Anti-Inflammatory Activity Studies.

    Science.gov (United States)

    Reena, K; Balashanmugam, P; Gajendiran, M; Antony, S Arul

    2016-05-01

    Gold nanoparticles (GNPs) are synthesized using the medicinal plant Leucas Aspera extract (LAE) and poly lactic acid-co-poly ethylene glycol-co-poly lactic acid (PLA-PEG-PLA) copolymer by water-in-oil (W/O) emulsion method. The proposed method of W/O emulsion technique involves synthesis of GNPs and loading of Leucas Aspera extract on to the PLA-PEG-PLA copolymer matrix simultaneously. The synthesized GNPs are characterized by Fourier transform infra-red (FTIR) spectroscopy, dynamic light scattering (DLS), X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The GNPs-LAE loaded polymer NPs are examined for the in vitro cytotoxicity on South African green monkey's kidney cells. The GNPs-LAE loaded polymer nanoconjugates exhibit maximum up to 95% of cell viability with 100 μg concentration of GNPs in the sample. The GNPs-LAE loaded polymer NPs exhibit better anti-inflammatory activity when compared to the pure LAE.

  20. Antioxidant, analgesic and anti-inflammatory activities of Leucas cephalotes (Roxb.ex Roth Spreng

    Directory of Open Access Journals (Sweden)

    Bhukya Baburao

    2010-09-01

    Full Text Available The whole plant of the methanolic extract from Leucas cephalotes was screened for invitro antioxidant (using the DPPH method, invivo analgesic (using hot plate test in mice and anti-inflammatory (using rat paw edema test activities. The methanolic extract of Leucas cephalotes (MELC scavenged the DPPH radicals in a dose-dependent manner. The IC50 value to scavenge DPPH radicals was found to be 421.3µg/ml. A significant (pO extrato metanólico total de Leucas cephalotes foi submetido à triagem para as atividades antioxidante in vitro (utilizando o método DPPH, analgésica (utilizando teste da placa quente, em camundongos e antiinflamatória (utilizando teste de edema da pata de rato, nas doses de 200 e 400 mg/kg. O extrato metanólico de Leucas cephalotes (MELC inativou radicais difenil picril hidrazila (DPPH de forma dose-dependente. O IC50 para essa atividade foi de 421,3 µg/mL. Observou-se atividade analgésica significativa (p<0,0005 a 60 minutos, com 200 mg/kg, e, com 400 mg/kg, observou-se atividade máxima. A resposta antiinflamatória máxima foi produzida, respectivamente, em 3 h e 2 h, com doses de 200 e 400 mg/kg. Estes resultados sugerem que o extrato metanólico de Leucas cephalotes apresenta efeitos analgésico e antiinflamatório significativos, comparáveis aos fármacos padrão.

  1. Feeding biomechanics and theoretical calculations of bite force in bull sharks (Carcharhinus leucas) during ontogeny.

    Science.gov (United States)

    Habegger, Maria L; Motta, Philip J; Huber, Daniel R; Dean, Mason N

    2012-12-01

    Evaluations of bite force, either measured directly or calculated theoretically, have been used to investigate the maximum feeding performance of a wide variety of vertebrates. However, bite force studies of fishes have focused primarily on small species due to the intractable nature of large apex predators. More massive muscles can generate higher forces and many of these fishes attain immense sizes; it is unclear how much of their biting performance is driven purely by dramatic ontogenetic increases in body size versus size-specific selection for enhanced feeding performance. In this study, we investigated biting performance and feeding biomechanics of immature and mature individuals from an ontogenetic series of an apex predator, the bull shark, Carcharhinus leucas (73-285cm total length). Theoretical bite force ranged from 36 to 2128N at the most anterior bite point, and 170 to 5914N at the most posterior bite point over the ontogenetic series. Scaling patterns differed among the two age groups investigated; immature bull shark bite force scaled with positive allometry, whereas adult bite force scaled isometrically. When the bite force of C. leucas was compared to those of 12 other cartilaginous fishes, bull sharks presented the highest mass-specific bite force, greater than that of the white shark or the great hammerhead shark. A phylogenetic independent contrast analysis of anatomical and dietary variables as determinants of bite force in these 13 species indicated that the evolution of large adult bite forces in cartilaginous fishes is linked predominantly to the evolution of large body size. Multiple regressions based on mass-specific standardized contrasts suggest that the evolution of high bite forces in Chondrichthyes is further correlated with hypertrophication of the jaw adductors, increased leverage for anterior biting, and widening of the head. Lastly, we discuss the ecological significance of positive allometry in bite force as a possible

  2. Habitat use and movement patterns of bull sharks Carcharhinus leucas determined using pop-up satellite archival tags.

    Science.gov (United States)

    Carlson, J K; Ribera, M M; Conrath, C L; Heupel, M R; Burgess, G H

    2010-08-01

    Habitat use, movement and residency of bull sharks Carcharhinus leucas were determined using satellite pop-up archival transmitting (PAT) tags throughout coastal areas in the U.S., Gulf of Mexico and waters off the south-east U.S. From 2005 to 2007, 18 fish (mean size = 164 cm fork length, L(F)) were tagged over all seasons. Fish retained tags for up to 85 days (median = 30 days). Based on geolocation data from initial tagging location to pop-off location, C. leucas generally travelled c. 5-6 km day(-1) and travelled an average of 143.6 km. Overall, mean proportions of time at depth revealed C. leucas spent the majority of their time in waters up the east coast of the U.S. to South Carolina. Data on C. leucas movements indicated that they are found primarily in shallower waters and tend to remain in the same location over long periods. While some individuals made large-scale movements over open ocean areas, the results emphasize the importance of the coastal zone for this species as potential essential habitat, particularly in areas of high freshwater inflow.

  3. Mechanism of antibacterial action of the alcoholic extracts of Hemidesmus indicus (L. R. Br. ex Schult, Leucas aspera (Wild., Plumbago zeylanica L and Tridax procumbens (L. R. Br. ex Schult.

    Directory of Open Access Journals (Sweden)

    Kongari eSaritha

    2015-06-01

    Full Text Available Herbal products derived from Hemidesmus indicus (L. R. Br. ex Schult, Leucas aspera (Wild., Plumbago zeylanica L and Tridax procumbens (L. R. Br. ex Schult. are widely used in traditional medicine.Though the extracts of these plants were found to be antimicrobial in nature and have the potential to be used in clinics, the mechanism of action of is not reported. The ethanolic extracts of Hemidesmus indicus (L. R. Br. ex Schult (HIEE, Leucas aspera (Wild.(Wild.(LAEE, Plumbago zeylanica L (PZEE and Tridax procumbens (L. R. Br. ex Schult. (TPEE were tested for their antibacterial activity against E. coli. Antibacterial activity was analyzed by CFU assay and the effect on the bacterial membrane by fluorescence activated cell sorting and scanning electron microscopy. LAEE, PZEE and HIEE displayed potent bacterial killing activity in a time and concentration dependent manner. TPEE did not display appreciable antibacterial activity. The antibacterial action involved disruption of membrane potential, inner membrane permeabilization , blebbing and leakage of cellular contents. Our results contribute to the understanding of the antibacterial mechanism of alcoholic extracts of the medicinal plants used in this study.

  4. Larvicidal potential of silver nanoparticles synthesized from Leucas aspera leaf extracts against dengue vector Aedes aegypti.

    Science.gov (United States)

    Suganya, Ganesan; Karthi, Sengodan; Shivakumar, Muthugounder S

    2014-05-01

    Vector-borne diseases caused by mosquitoes are one of the major economic and health problems in many countries. The Aedes aegypti mosquito is a vector of several diseases in humans like yellow fever and dengue. Vector control methods involving the use of chemical insecticides are becoming less effective due to development of insecticides resistance, biological magnification of toxic substances through the food chain, and adverse effects on environmental quality and non-target organisms including human health. Application of active toxic agents from plant extracts as an alternative mosquito control strategy was available from ancient times. These are nontoxic, easily available at affordable prices, biodegradable, and show broad-spectrum target-specific activities against different species of vector mosquitoes. Today, nanotechnology is a promising research domain which has wide-ranging application vector control programs. The present study investigates the larvicidal potential of solvent leaf extracts of Leucas aspera and synthesized silver nanoparticles using aqueous leaf extract against fourth instar larvae of Aedes aegypti. Larvae were exposed to varying concentrations of plant extracts and synthesized AgNPs for 24 h. The results were recorded from UV-Vis spectra, x-ray diffraction (XRD), Fourier transform infrared (FT-IR), and scanning electron microscopy (SEM), and were used to characterize and support the biosynthesis of silver nanoparticles. The formation of the AgNPs synthesized from the XRD spectrum compared with Bragg reflections can be indexed to the (111) orientations, respectively, confirmed the presence of AgNPs. The FT-IR spectra of AgNPs exhibited prominent peaks at 3,447.77; 2,923.30; and 1,618.66 cm(-1). The spectra showed sharp and strong absorption band at 1,618.66 cm(-1) assigned to the stretching vibration of (NH) C═O group. The band 1,383 developed for C═C and C═N stretching, respectively, and was commonly found in the proteins. SEM

  5. Uptake of human pharmaceuticals in bull sharks (Carcharhinus leucas) inhabiting a wastewater-impacted river.

    Science.gov (United States)

    Gelsleichter, James; Szabo, Nancy J

    2013-07-01

    The presence of human pharmaceuticals in sewage-impacted ecosystems is a growing concern that poses health risks to aquatic wildlife. Despite this, few studies have investigated the uptake of active pharmaceutical ingredients (APIs) in aquatic organisms. In this study, the uptake of 9 APIs from human drugs was examined and compared in neonate bull sharks (Carcharhinus leucas) residing in pristine (Myakka River) and wastewater-impacted (Caloosahatchee River) tributaries of Florida's Charlotte Harbor estuary. The synthetic estrogen used in human contraceptives (17α-ethynylestradiol) and 6 of the selective serotonin/norepinephrine reuptake inhibitors (citalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, venlafaxine) used in human antidepressants were observed at detectable and, in some cases, quantifiable levels in plasma of Caloosahatchee River sharks. Comparatively, only venlafaxine was detected in the plasma of a single Myakka River shark at a level below the limit of quantitation. These results suggest that sharks residing in wastewater-impacted habitats accumulate APIs, a factor that may pose special risks to C. leucas since it is one of few shark species to regularly occupy freshwater systems. Further research is needed to determine if the low levels of API uptake observed in Caloosahatchee River bull sharks pose health risks to these animals.

  6. The 2015, Mw 6.5, Leucas (Ionian Sea, Greece) earthquake: Seismological and Geodetic Modelling

    Science.gov (United States)

    Saltogianni, Vasso; Taymaz, Tuncay; Yolsal-Çevikbilen, Seda; Eken, Tuna; Moschas, Fanis; Stiros, Stathis

    2016-04-01

    A cluster of earthquakes (6Greece, in the last 30 years. The most recent earthquake was the 2015 (Mw 6.5) Leucas (Lefkada) earthquake. The modelling of these earthquakes, some of which are double events (2003 Leucas; 2014 Cephalonia) is a challenge for two main reasons. First, the geography of the area limits the distribution of the available seismological and GNSS stations and the correlations of INSAR data. Second, the structural pattern of the area indicates distributed thrusting but recent earthquakes are confined to the west margin of the Aegean Arc, usually assigned to the Cephalonia Transform Fault (CTF), and are dominated by strike slip faulting. In order to contribute to the understanding active tectonics along this critical region, our study was based on the independent analysis of the seismological and geodetic signature of the 2015 earthquake and the on the joint evaluation of the inferred models on the basis of the fault pattern of the area and of previous earthquakes. First, based on teleseismic long-period P- and SH- and broad-band P-waveforms a point-source solution at the SW part of Leucas yielded dominantly right-lateral strike-slip faulting mechanisms (strike: 23o, dip: 68o, rake: -170o) with a shallow focal depth (h: 9 km) and with seismic moment of Mo: 10.4x1018 Nm. Furthermore, the rupture history of the earthquake was obtained by applying a new back-projection method that uses teleseismic P-waveforms to integrate the direct P-phase with reflected phases from structural discontinuities near the source. In the slip inversion the faulting occurs on a single fault plane (strike and dip are obtained from the best fitting point-source solution) and slip (rake) angle varied during the whole rupture process. Second, co-seismic displacements were derived from eight permanent and one campaign GPS stations spread in the near and far field of the meizoseismal area. Significant horizontal slip was recognized, with a maximum dislocation of 36 cm in the SW

  7. Inhibition of Naja naja venom enzymes by the methanolic extract of Leucas aspera and its chemical profile by GC–MS

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    Kadiyala Gopi

    2014-01-01

    Conclusion: The results obtained demonstrate for the first time that the methanolic extract of Leucas aspera possesses anti-venom activity and could be considered as a potential source for the anti-ophidian metabolites.

  8. Feeding behavior of Frontonia leucas (Ehrenberg (Protozoa, Ciliophora, Hymenostomatida under different environmental conditions in a lotic system Comportamento alimentar de Frontonia leucas (Ehrenberg (Protozoa, Ciliophora, Hymenostomatida sob diferentes condições ambientais em um sistema lótico

    Directory of Open Access Journals (Sweden)

    Roberto Júnio P. Dias

    2006-09-01

    Full Text Available The objective of this study was to record and describe the morphological changes and the ingestion mechanisms of Frontonia leucas (Ehrenberg, 1833 according to the food type and to relate the food ingested with the different environmental conditions in a lotic system, namely São Pedro stream, located in the municipality of Juiz de Fora, Minas Gerais, Brazil. We sampled three points on a monthly basis from August 2002 to June 2003, each of which receiving different levels of untreated sewage. We prepared culture media for the ciliate specimens containing filtered water from each point and the types of food observed inside F. leucas (cyanobacteria, diatoms, desmids and testate amoebas. We observed the ingestion mechanisms of F. leucas in vivo, under a phase contrast optical microscope, using instantaneous sampling and sequence sampling as behavior observation methods, noting the following parameters: dissolved oxygen concentration, pH, conductivity and water temperature. We noted the F. leucas ciliates ingesting diatoms and desmids at collection point 1 and filamentous cyanobacteria, testate amoebas (Arcella and Centropyxis and rotifers at points 2 and 3. The present work records for the first time the ingestion of testate amoebas of the genus Centropyxis by F. leucas. We noted five ingestion mechanisms by F. leucas while feeding on cyanobacteria and testate amoebas of the genus Centropyxis, three of these related to the ciliary action and two involving physical changes in the cytoplasm. For ingestion of diatoms, desmid (Closterium and Arcella, the mechanisms involving ciliary action alone were sufficient for ingestion, since these preys are smaller than the ciliate under study. The autecological data registered for F. leucas were 1.98-8.01 mg l-1 O2, pH 6.9-8.73, 58-390 µS/cm and 19.5-26.2ºC, confirming its ample ecological valence.O objetivo do presente trabalho foi registrar e descrever as alterações morfológicas e os mecanismos de ingest

  9. Reversed phase high-performance liquid chromatographic ultra-violet (photo diode array quantification of oleanolic acid and its isomer ursolic acid for phytochemical comparison and pharmacological evaluation of four Leucas species used in ayurveda

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    Pushpendra Kumar Shukla

    2016-01-01

    SUMMARY Physicochemical parameters are within the limit as per the Ayurvedic Pharmacopoeia of IndiaMaximum concentration of oleanolic acid was found in Leucas cristata; however, ursolic acid was highest in Leucas mollissimaIn vitro antidiabetic activity of Leucas aspera and L. mollissima was found tobe heighest as compared to other species. However, antioxidant capacity is almost similar in targeted species.Promising activities were observed in all the species, thus L. mollissima, Leucas biflora, and L. cristata can be used alternatively as a substitute to L. aspera.

  10. EVALUATION OF THE EXTRACTS OF LEUCAS ASPERA ON BIOCHEMICAL PROFILES IN EXPERIMENTAL MODEL OF DIABETES MELLITUS (TYPE- I IN RATS

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    T.Tukaram

    2011-03-01

    Full Text Available The study was conducted to evaluate the effect of Leucas aspera leaves on experimental diabetes mellitus (type I in rats in terms of alterations in biochemical profiles. Thirty rats were randomly divided into six groups of 5 rats in each. Group-I were fed on basal diet without any treatment, group-II induced diabetic models (type-I (Alloxan monohydrate dissolved in sterile normal saline (150 mg/kgBW, ip, group-III, IV, V and VI were induced diabetics and treated with extract of Leucas aspera (30,100,150 and 300mg/kg BW respectively, PO twice daily in the morning and evening post prandially for thirty days respectively. The blood samples were collected on day 0, 10, 20 and 30 and were used for the analysis of biochemical profiles.The blood glucose (mg% were consistently increased significantly (P<0.01 in groups II,III, IV V and VI till day 20 while in groups V and VI there was a significant (P<0.01 decline in the values on day 30. There was found to have profound effect in lowering the blood glucose levels in dose dependent manner. The study revealed that experimental diabetes mellitus (type-I induced patho-biochemical changes were ameliorated more effectively by ethanolic extract of Leucas aspera in dose dependent manner.

  11. Age-related polychlorinated biphenyl dynamics in immature bull sharks (Carcharhinus leucas).

    Science.gov (United States)

    Olin, Jill A; Beaudry, Marina; Fisk, Aaron T; Paterson, Gordon

    2014-01-01

    Polychlorinated biphenyls (PCBs) were quantified in liver tissues of bull sharks (Carcharhinus leucas) ranging in age from 3 yr. Summed values of PCBs (ΣPCBs) ranged from 310 ng/g to 22 070 ng/g (lipid wt) across age classes with ΣPCB concentrations for the youngest sharks in the present study (3-yr-old sharks, highlighting the extent of exposure of this young life stage to this class of persistent organic pollutants (POPs). Age normalization of PCB congener concentrations to those measured for the youngest sharks demonstrated a significant hydrophobicity (log octanol/water partition coefficient [KOW ]) effect that was indicative of maternal offloading of highly hydrophobic (log KOW ≥6.5) congeners to the youngest individuals. A distinct shift in the PCB congener profiles was also observed as these young sharks grew in size. This shift was consistent with a transition from the maternally offloaded signal to the initiation of exogenous feeding and the contributions of mechanisms including growth dilution and whole-body elimination. These results add to the growing pool of literature documenting substantially high concentrations of POPs in juvenile sharks that are most likely attributable to maternal offloading. Collectively, such results underscore the potential vulnerability of young sharks to POP exposure and pose additional concerns for shark-conservation efforts.

  12. Leucas aspera mediated multifunctional CeO2 nanoparticles: Structural, photoluminescent, photocatalytic and antibacterial properties.

    Science.gov (United States)

    Malleshappa, J; Nagabhushana, H; Sharma, S C; Vidya, Y S; Anantharaju, K S; Prashantha, S C; Daruka Prasad, B; Raja Naika, H; Lingaraju, K; Surendra, B S

    2015-01-01

    Spherical shaped cerium dioxide (CeO2) nanoparticles (NPs) were synthesized via bio mediated route using Leucas aspera (LA) leaf extract. The NPs were characterized by PXRD, SEM, UV-Visible techniques. Photoluminescence (PL), photocatalysis and antibacterial properties of NPs were studied. PXRD patterns and Rietveld analysis confirm cubic fluorite structure with space group Fm-3m. SEM results evident that morphology of the NPs was greatly influenced by the concentration of LA leaf extract in the reaction mixture. The band gap energy of the NPs was found to be in the range of 2.98-3.4 eV. The photocatalytic activity of NPs was evaluated by decolorization of Rhodamine-B (RhB) under UVA and Sun light irradiation. CeO2 NPs show intense blue emission with CIE coordinates (0.14, 0.22) and average color coordinated temperature value ∼148,953 K. Therefore the present NPs quite useful for cool LEDs. The superior photocatalytic activity was observed for CeO2 NPs with 20 ml LA under both UVA and Sunlight irradiation. The enhanced photocatalytic activity and photoluminescent properties were attributed to defect induced band gap engineered CeO2 NPs. Further, CeO2 with 20 ml LA exhibit significant antibacterial activity against Escherichia coli (EC) and Staphylococcus aureus (SA). These findings show great promise of CeO2 NPs as multifunctional material for various applications.

  13. Ulcer protective effect of Leucas aspera in various experimental ulcer models

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    Bibin Baby Augustine

    2014-02-01

    Full Text Available Objective: To investigate the ulcer protective effect of Leucas aspera (L. aspera aerial parts in various experimental ulcer models. Methods: Aerial parts of L. aspera were collected and extracted with methanol (70% v/v. Preliminary phytochemical screening and toxicity evaluation of methanolic extract of L. aspera were performed. Ulcer protective effect of methanolic extract of L. aspera was checked using various in vivo experimental ulcer models (indomethacin plus restraint model, swimming induced stress ulcer, serotonin induced gastric ulcer, cysteamine induced duodenal ulcer, ethanol induced gastric ulcer. Antioxidant and histopathological studies of gastric mucosa were conducted in ethanol induced ulcer model. Results: Methanolic extract of L. aspera did not show any toxic reactions in both acute and short term toxicity studies. Moreover, methanolic extract of L. aspera showed powerful antisecretory and ulcer protective effect in all the tested ulcer models. Results of antioxidant and histopathological studies further confirmed the ulcer protective effect of methanolic extract of L. aspera. Conclusions: The present study justifies the folkloric use of L. aspera in various gastric disorders. Further studies should be conducted to find the mechanism of action.

  14. Biodiversity of the white coral bank off Cape Santa Maria di Leuca (Mediterranean Sea): An update

    Science.gov (United States)

    Mastrototaro, F.; D'Onghia, G.; Corriero, G.; Matarrese, A.; Maiorano, P.; Panetta, P.; Gherardi, M.; Longo, C.; Rosso, A.; Sciuto, F.; Sanfilippo, R.; Gravili, C.; Boero, F.; Taviani, M.; Tursi, A.

    2010-03-01

    The biodiversity of the Santa Maria di Leuca (SML) coral bank is summarized and its description is updated using data collected by means of underwater video systems, benthic samplers and fishing gears. A total of 222 living species have been recorded within the coral bank area in the depth range 280-1121 m. The most abundant benthic taxa recorded are Porifera (36 species) followed by Mollusca (35) and Cnidaria (31). The scleractinian corals Madrepora oculata and Lophelia pertusa are the main colonial species in the structure of the SML bank. Annelida, Crustacea and Bryozoa have been found with 24, 23 and 19 species, respectively. A total of 40 species of demersal fish have been recorded. Other faunal taxa were found with small numbers of species. One hundred and thirty-five species are new for the SML bank, 31 of which represent new records for the north-western Ionian Sea (2 Porifera, 17 Cnidaria, 1 Mollusca, 3 Annelida, 2 Crustacea, 4 Bryozoa and 4 Echinodermata). The finding of the annelid Harmothoë vesiculosa represents the first record for the Mediterranean Sea. The SML coral bank represents a biodiversity "hot-spot" on the bathyal bottoms of the Mediterranean Sea.

  15. Studies on larvicidal and pupicidal activity of Leucas aspera Willd. (Lamiaceae) and bacterial insecticide, Bacillus sphaericus, against malarial vector, Anopheles stephensi Liston (Diptera: Culicidae)

    Science.gov (United States)

    The efficacy of whole plant ethanolic extracts of Leucas aspera and of Bacillus sphaericus was determined for larvae and pupae of Anopheles stephensi. When larvae were exposed to one of five concentrations of plant extract (6%, 8%, 10%, 12%, and 14%) for 24 h, mortality in 4th instars ranged from 1...

  16. Natural or artificial? Habitat-use by the bull shark, Carcharhinus leucas.

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    Jonathan M Werry

    Full Text Available BACKGROUND: Despite accelerated global population declines due to targeted and illegal fishing pressure for many top-level shark species, the impacts of coastal habitat modification have been largely overlooked. We present the first direct comparison of the use of natural versus artificial habitats for the bull shark, Carcharhinus leucas, an IUCN 'Near-threatened' species--one of the few truly euryhaline sharks that utilises natural rivers and estuaries as nursery grounds before migrating offshore as adults. Understanding the value of alternate artificial coastal habitats to the lifecycle of the bull shark is crucial for determining the impact of coastal development on this threatened but potentially dangerous species. METHODOLOGY/FINDINGS: We used longline surveys and long-term passive acoustic tracking of neonate and juvenile bull sharks to determine the ontogenetic value of natural and artificial habitats to bull sharks associated with the Nerang River and adjoining canals on the Gold Coast, Australia. Long-term movements of tagged sharks suggested a preference for the natural river over artificial habitat (canals. Neonates and juveniles spent the majority of their time in the upper tidal reaches of the Nerang River and undertook excursions into adjoining canals. Larger bull sharks ranged further and frequented the canals closer to the river mouth. CONCLUSIONS/SIGNIFICANCE: Our work suggests with increased destruction of natural habitats, artificial coastal habitat may become increasingly important to large juvenile bull sharks with associated risk of attack on humans. In this system, neonate and juvenile bull sharks utilised the natural and artificial habitats, but the latter was not the preferred habitat of neonates. The upper reaches of tidal rivers, often under significant modification pressure, serve as nursery sites for neonates. Analogous studies are needed in similar systems elsewhere to assess the spatial and temporal generality of

  17. Morphology of the ampullae of Lorenzini in juvenile freshwater Carcharhinus leucas.

    Science.gov (United States)

    Whitehead, Darryl L; Gauthier, Arnault R G; Mu, Erica W H; Bennett, Mike B; Tibbetts, Ian R

    2015-05-01

    Ampullae of Lorenzini were examined from juvenile Carcharhinus leucas (831-1,045 mm total length) captured from freshwater regions of the Brisbane River. The ampullary organ structure differs from all other previously described ampullae in the canal wall structure, the general shape of the ampullary canal, and the apically nucleated supportive cells. Ampullary pores of 140-205 µm in diameter are distributed over the surface of the head region with 2,681 and 2,913 pores present in two sharks that were studied in detail. The primary variation of the ampullary organs appears in the canal epithelial cells which occur as either flattened squamous epithelial cells or a second form of pseudostratified contour-ridged epithelial cells; both cell types appear to release material into the ampullary lumen. Secondarily, this ampullary canal varies due to involuted walls that form a clover-like canal wall structure. At the proximal end of the canal, contour-ridged cells abut a narrow region of cuboidal epithelial cells that verge on the constant, six alveolar sacs of the ampulla. The alveolar sacs contain numerous receptor and supportive cells bound by tight junctions and desmosomes. Pear-shaped receptor cells that possess a single apical kinocilium are connected basally by unmyelinated neural boutons. Opposed to previously described ampullae of Lorenzini, the supportive cells have an apical nucleus, possess a low number of microvilli, and form a unique, jagged alveolar wall. A centrally positioned centrum cap of cuboidal epithelial cells overlies a primary afferent lateral line nerve. © 2014 Wiley Periodicals, Inc.

  18. Antioxidant, antibacterial and cytotoxic effects of the phytochemicals of whole Leucas aspera extract

    Science.gov (United States)

    Rahman, Md Atiar; Islam, Md Saiful

    2013-01-01

    Objective To investigate the antioxidant, antibacterial and cytotoxic activity of whole Leucas aspera (Labiatae) (L. aspera) alcoholic extract. Methods Whole L. aspera powder was extracted by absolute ethanol (99.50%). The ethanolic extract was subjected to antioxidant, antibacterial and brine shrimp lethality assay. Results The extract showed potent radical scavenging effect (antioxidant) with IC50 value of (99.58±1.22) µg/mL which was significant (P<0.01) in comparison to ascorbic acid with IC50 value of (1.25±0.95) µg/mL. In case of antibacterial screening, the extract showed notable antibacterial effect against the tested microbial strains. Significant (P<0.05) zone of inhibitions against Gram positive Bacillus subtilis [(12.00±1.32) mm] and Bacillus megaterium [(13.00±1.50) mm], Staphylococcus aureus [(8.00±0.50) mm] and Gram negative Salmonella typhi [(6.00±0.50) mm], Salmonella paratyphi [(8.00±1.00) mm], Shigella dysenteriae [(9.00±1.32) mm] and Vibrio cholerae [(9.00±0.66) mm] was observed. In brine shrimp lethality bioassay, the extract showed the LC50 value as (181.68±2.15) µg/mL which was statistically significant (P<0.01) compared to positive control vincristine sulfate [LC50=(0.76±0.04) µg/mL]. Conclusions The results demonstrate that the ethanolic extract of L. aspera could be used as antibacterial, pesticidal and various pharmacologic actives. PMID:23620850

  19. Mechanism of antibacterial action of the alcoholic extracts of Hemidesmus indicus (L.) R. Br. ex Schult, Leucas aspera (Wild.), Plumbago zeylanica L., and Tridax procumbens (L.) R. Br. ex Schult

    OpenAIRE

    Saritha, Kongari; Rajesh, Angireddy; Manjulatha, Khanapur; Setty, Oruganti H.; Yenugu, Suresh

    2015-01-01

    Herbal products derived from Hemidesmus indicus (L.) R. Br. ex Schult, Leucas aspera (Wild.), Plumbago zeylanica L., and Tridax procumbens (L.) R. Br. ex Schult. are widely used in traditional medicine. Though the extracts of these plants were found to be antimicrobial in nature and have the potential to be used in clinics, the mechanism of action of is not reported. The ethanolic extracts of Hemidesmus indicus (L.) R. Br. ex Schult, Hemidesmus indicus ethanolic extract (HIEE), Leucas aspera ...

  20. AFSC/NMML: Beluga whale aerial survey in Cook Inlet, Alaska, 1993-2014

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Marine Fisheries Service (NMFS) has conducted aerial counts of Cook Inlet beluga whales (Delphinapterus leucas) from 1993 to 2014 (excluding 2013)....

  1. Beluga whales aerial survey conducted by Alaska Fisheries Scientific Center, National Marine Mammal Laboratory from 1993-06-02 to 2014-06-12 (NCEI Accession 0133936)

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The National Marine Fisheries Service (NMFS) has conducted aerial counts of Cook Inlet beluga whales (Delphinapterus leucas) from 1993 to 2014 (excluding 2013)....

  2. Aerial Surveys of Bowhead Whales, North Slope, Alaska.

    Science.gov (United States)

    1980-02-01

    general area were 15 to 20 belugas ( Delphinapterus leucas ). They were evenly spaced and were proceeding quite steadily in straight, regular lines on...in polynyas within the ice. In early spring, whales from this population move northward from the Bering Sea, passing St Lawrence and Diomede Islands...Harvard Univ. Press Cambridge. MA. Sergeant. D.E. and W. Hoch. 1974. Biology of bowhead Balaena mysticetus and white whale Delphinapterus leucas in

  3. Distribution, Abundance, Behavior, and Bioacoustics of Endangered Whales in the Alaskan Beaufort and Eastern Chukchi Seas, 1979-86.

    Science.gov (United States)

    1987-07-01

    Habitat Relationships and Behavior 70 d. Calf Sightings and Estimated Recruitment 72 Other Marine Mammals 72 a. Belukha ( Delphinapterus leucas ) 72 b...been seen in the Chukchi Sea only in 3uly. Other Marine Mammals a. Belukha, or White Whale ( Delphinapterus leucas ) There were 109 sightings of 492...physalus) whales in the St . Lawrence river (Macfarlane, 1981); and minke whales (Balaenoptera acutorostrata) off 3apan (Nishiwaki and Sasao, 1977

  4. Antioxidant,antibacterial and cytotoxic effects of the phytochemicals of whole Leucas aspera extract

    Institute of Scientific and Technical Information of China (English)

    Md; Atiar; Rahman; Md; Saiful; Islam

    2013-01-01

    Objective:To investigate the antioxidant,antibacterial and cytotoxic activity of whole Leucas aspera(Labiatae)(L.aspera)alcoholic extract.Methods:Whole L.aspera powder was extracted by absolute ethanol(99.50%).The ethanolic extract was subjected to antioxidant,antibacterial and brine shrimp lethality assay.Results:The extract showed potent radical scavenging effect(antioxidant)with IC50value of(99.58±1.22)μg/mL which was significant(P<0.01)in comparison to ascorbic acid with IC50value of(1.25±0.95)μg/mL.In case of antibacterial screening,the extract showed notable antibacterial effect against the tested microbial strains.Significant(P<0.05)zone of inhibitions against Gram positive Bacillus subtilis[(12.00±1.32)mm]and Bacillus megaterium[(13.00±1.50)mm],Staphylococcus aureus[(8.00±0.50)mm]and Gram negative Salmonella typhi[(6.00±0.50)mm],Salmonella paratyphi[(8.00±1.00)mm],Shigella dysenteriae[(9.00±1.32)mm]and Vibrio cholerae[(9.00±0.66)mm]was observed.In brine shrimp lethality bioassay,the extract showed the LC50value as(181.68±2.15)μg/mL which was statistically significant(P<0.01)compared to positive control vincristine sulfate[LC50=(0.76±0.04)μg/mL].Conclusions:The results demonstrate that the ethanolic extract of L.aspera could be used as antibacterial,pesticidal and various pharmacologic actives.

  5. Larvicidal and pupicidal activity of synthesized silver nanoparticles using Leucas aspera leaf extract against mosquito vectors, Aedes aegypti and Anopheles stephensi

    OpenAIRE

    S. Sivapriyajothi; P. Mahesh Kumar; K. Kovendan; Subramaniam, J; K Murugan

    2014-01-01

    Mosquitoes are one of the most medically significant groups of vectors, having an ability to transmit parasites and pathogens that can have devastating impacts on humans. The development of reliable and ecofriendly processes for the synthesis of metallic nanoparticles is an important step in the field of application of nanotechnology. In this study, we address the biosynthesis of silver nanoparticles (AgNPs) using Leucas aspera leaf extract, and evaluate its lethal concentration (LC50 and LC9...

  6. Larvicidal and pupicidal activity of synthesized silver nanoparticles using Leucas aspera leaf extract against mosquito vectors, Aedes aegypti and Anopheles stephensi

    Directory of Open Access Journals (Sweden)

    S. Sivapriyajothi

    2014-08-01

    Full Text Available Mosquitoes are one of the most medically significant groups of vectors, having an ability to transmit parasites and pathogens that can have devastating impacts on humans. The development of reliable and ecofriendly processes for the synthesis of metallic nanoparticles is an important step in the field of application of nanotechnology. In this study, we address the biosynthesis of silver nanoparticles (AgNPs using Leucas aspera leaf extract, and evaluate its lethal concentration (LC50 and LC90 values against first to fourth instar larvae and pupae of the mosquito vectors, Aedes aegypti and Anopheles stephensi. The nanoparticles were characterized by UV-Vis spectrum, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and Fourier-transformed infrared spectroscopy analysis. Larvae and pupae were exposed to varying concentrations of aqueous extracts of synthesized AgNPs for 24 h. The maximum mortality was observed from synthesized AgNPs, with LC50 values for I-IV instars and pupae ranging from 13.06 to 25.54, and LC90 values ranging from 24.11 to 47.34 for A. aegypti; for A. stephensi, the corresponding LC50 values ranged from 12.45 to 22.26, and the LC90 values ranged from 23.50 to 42.95. With methanol leaf extract of L. aspera against A. aegypti, the LC50 values ranged from 174.89 to 462.96 and the LC90 values ranged from 488.16 to 963.74; for A. stephensi, the corresponding LC50 values ranged from 148.93 to 417.07 and the LC90 values ranged from 449.72 to 912.94. The study suggests that nanoparticles could be a preferred alternative to the most hazardous existing chemical pesticides, contributing to a more healthy environment by providing an ideal ecological and user-friendly vector control strategy for managing malaria and dengue, and contributing to their eventual elimination in the near future.

  7. Chemical Composition, In Vitro Antimicrobial, Free-Radical-Scavenging and Antioxidant Activities of the Essential Oil of Leucas inflata Benth

    Directory of Open Access Journals (Sweden)

    Ramzi A. Mothana

    2017-02-01

    Full Text Available The essential oil of Leucas inflata Balf.f. (Lamiaceae, collected in Yemen, was analyzed using gas chromatography (GC and gas chromatography-mass spectrometry (GC-MS techniques. Forty-three components were recognized, representing 89.2% of the total oil. The L. inflata volatile oil was found to contain a high percentage of aliphatic acids (51.1%. Hexadecanoic acid (32.8% and n-dodecanoic acid (7.8% were identified as the major compounds. Oxygenated monoterpenes were distinguished as the second significant group of constituents (16.0%. Camphor (6.1% and linalool (3.2% were found to be the main components among the oxygenated monoterpenes. In addition, the volatile oil was assessed for its antimicrobial activity against four bacterial strains and one yeast species using broth micro-dilution assay for minimum inhibitory concentrations (MIC. In addition, antioxidant activity was measured utilizing the anti-radical activity of the sable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH and β-Carotene-linoleic acid assays. The oil of L. inflata showed an excellent antibacterial activity against only the tested Gram-positive bacteria with a MIC-value of 0.81 mg/mL. Furthermore, the oil demonstrated, at a concentration of 1 mg/mL, a weak to moderate antiradical and antioxidant activity of 38% and 32%, respectively.

  8. Spatiotemporal bioerosion patterns in deep-water scleractinians from off Santa Maria di Leuca (Apulia, Ionian Sea)

    Science.gov (United States)

    Beuck, L.; Freiwald, A.; Taviani, M.

    2010-03-01

    This study focuses on the carbonate biodegradation processes of deep-water scleractinians from off Apulia at Santa Maria di Leuca (SML) in the Ionian Sea, including living colonies of Lophelia pertusa, Madrepora oculata and Desmophyllum dianthus. The corallites were grouped into three zones: the live zone, edge zone and dead zone. In total, 13 trace types were encountered and are attributed to borings of sponges (3), fungi (6), foraminifers (2), bacteria (1) and annelids (1). Their relative spatial appearance within the host skeletons led to the distinction between six succession stages of bioerosion. The first endobiontic traces are exclusively produced by bacteria and fungi and are already present in the edge zone, which could be attributed to their fast growth rates and/or temporal exposure of the bare skeleton to the water column. In D. dianthus the entire ichnospecies assemblage has been documented within the first 1.9 cm below the live zone and represents the most condensed bioerosion succession amongst the coral species studied. The strongest degradation of corallites at SML is made by boring sponges, which can excavate 70% or more of the skeleton. The finding of a unilateral condensed succession of bioerosion stages may be linked to prevailing unidirectional strong currents. A comparison of the present ichnocoenosis with bioerosion studies from the Eastern Atlantic evidences a reduced ichnodiversity in Ionian Sea bathyal corals.

  9. Residency patterns and migration dynamics of adult bull sharks (Carcharhinus leucas) on the east coast of southern Africa.

    Science.gov (United States)

    Daly, Ryan; Smale, Malcolm J; Cowley, Paul D; Froneman, Pierre W

    2014-01-01

    Bull sharks (Carcharhinus leucas) are globally distributed top predators that play an important ecological role within coastal marine communities. However, little is known about the spatial and temporal scales of their habitat use and associated ecological role. In this study, we employed passive acoustic telemetry to investigate the residency patterns and migration dynamics of 18 adult bull sharks (195-283 cm total length) tagged in southern Mozambique for a period of between 10 and 22 months. The majority of sharks (n = 16) exhibited temporally and spatially variable residency patterns interspersed with migration events. Ten individuals undertook coastal migrations that ranged between 433 and 709 km (mean  = 533 km) with eight of these sharks returning to the study site. During migration, individuals exhibited rates of movement between 2 and 59 km x d(-1) (mean = 17.58 km x d(-1)) and were recorded travelling annual distances of between 450 and 3760 km (mean = 1163 km). Migration towards lower latitudes primarily took place in austral spring and winter and there was a significant negative correlation between residency and mean monthly sea temperature at the study site. This suggested that seasonal change is the primary driver behind migration events but further investigation is required to assess how foraging and reproductive activity may influence residency patterns and migration. Results from this study highlight the need for further understanding of bull shark migration dynamics and suggest that effective conservation strategies for this vulnerable species necessitate the incorporation of congruent trans-boundary policies over large spatial scales.

  10. Distribution and dynamic habitat use of young bull sharks Carcharhinus leucas in a highly stratified northern Gulf of Mexico estuary.

    Science.gov (United States)

    Drymon, J Marcus; Ajemian, Matthew J; Powers, Sean P

    2014-01-01

    Understanding how animals alter habitat use in response to changing abiotic conditions is important for effective conservation management. For bull sharks (Carcharhinus leucas), habitat use has been widely examined in the eastern and western Gulf of Mexico; however, knowledge of their movements and the factors influencing them is lacking for populations in the more temperate north-central Gulf of Mexico. To examine how changes in hydrographic conditions affected the presence of young bull sharks in Mobile Bay, Alabama, thirty-five sharks were fitted with internal acoustic transmitters and monitored with an acoustic monitoring array consisting of thirty-three receivers between June 2009 and December 2010. Tagged sharks ranged in size from 60 to 114 cm fork length and were detected between the upper and lower portions of Mobile Bay. Despite a variety of freshwater sources associated with this highly productive estuary, sharks were most consistently detected at the largest input to the system--the Mobile and Tensaw Rivers. Our findings suggest a combination of hydrographic factors interact to influence the distribution of juvenile bull sharks in Mobile Bay. The factors affecting the probability of detecting at least one bull shark varied both temporally (2009 vs 2010) and spatially (upper vs lower bay). Electivity analysis demonstrated that bull sharks showed highest affinity for warm water (29-32 °C), moderate salinities (10-11 psu) and normoxic waters (5-7 mg/l), although these patterns were not consistent between regions or across years. We suggest future studies coupling telemetry and hydrographic variables should, when possible, consider the interactions of multiple environmental parameters when defining the dynamic factors explaining the spatial distribution of coastal sharks.

  11. Distribution and dynamic habitat use of young bull sharks Carcharhinus leucas in a highly stratified northern Gulf of Mexico estuary.

    Directory of Open Access Journals (Sweden)

    J Marcus Drymon

    Full Text Available Understanding how animals alter habitat use in response to changing abiotic conditions is important for effective conservation management. For bull sharks (Carcharhinus leucas, habitat use has been widely examined in the eastern and western Gulf of Mexico; however, knowledge of their movements and the factors influencing them is lacking for populations in the more temperate north-central Gulf of Mexico. To examine how changes in hydrographic conditions affected the presence of young bull sharks in Mobile Bay, Alabama, thirty-five sharks were fitted with internal acoustic transmitters and monitored with an acoustic monitoring array consisting of thirty-three receivers between June 2009 and December 2010. Tagged sharks ranged in size from 60 to 114 cm fork length and were detected between the upper and lower portions of Mobile Bay. Despite a variety of freshwater sources associated with this highly productive estuary, sharks were most consistently detected at the largest input to the system--the Mobile and Tensaw Rivers. Our findings suggest a combination of hydrographic factors interact to influence the distribution of juvenile bull sharks in Mobile Bay. The factors affecting the probability of detecting at least one bull shark varied both temporally (2009 vs 2010 and spatially (upper vs lower bay. Electivity analysis demonstrated that bull sharks showed highest affinity for warm water (29-32 °C, moderate salinities (10-11 psu and normoxic waters (5-7 mg/l, although these patterns were not consistent between regions or across years. We suggest future studies coupling telemetry and hydrographic variables should, when possible, consider the interactions of multiple environmental parameters when defining the dynamic factors explaining the spatial distribution of coastal sharks.

  12. A comparison of spatial and movement patterns between sympatric predators: bull sharks (Carcharhinus leucas and Atlantic tarpon (Megalops atlanticus.

    Directory of Open Access Journals (Sweden)

    Neil Hammerschlag

    Full Text Available BACKGROUND: Predators can impact ecosystems through trophic cascades such that differential patterns in habitat use can lead to spatiotemporal variation in top down forcing on community dynamics. Thus, improved understanding of predator movements is important for evaluating the potential ecosystem effects of their declines. METHODOLOGY/PRINCIPAL FINDINGS: We satellite-tagged an apex predator (bull sharks, Carcharhinus leucas and a sympatric mesopredator (Atlantic tarpon, Megalops atlanticus in southern Florida waters to describe their habitat use, abundance and movement patterns. We asked four questions: (1 How do the seasonal abundance patterns of bull sharks and tarpon compare? (2 How do the movement patterns of bull sharks and tarpon compare, and what proportion of time do their respective primary ranges overlap? (3 Do tarpon movement patterns (e.g., straight versus convoluted paths and/or their rates of movement (ROM differ in areas of low versus high bull shark abundance? and (4 Can any general conclusions be reached concerning whether tarpon may mitigate risk of predation by sharks when they are in areas of high bull shark abundance? CONCLUSIONS/SIGNIFICANCE: Despite similarities in diet, bull sharks and tarpon showed little overlap in habitat use. Bull shark abundance was high year-round, but peaked in winter; while tarpon abundance and fishery catches were highest in late spring. However, presence of the largest sharks (>230 cm coincided with peak tarpon abundance. When moving over deep open waters (areas of high shark abundance and high food availability tarpon maintained relatively high ROM in directed lines until reaching shallow structurally-complex areas. At such locations, tarpon exhibited slow tortuous movements over relatively long time periods indicative of foraging. Tarpon periodically concentrated up rivers, where tracked bull sharks were absent. We propose that tarpon trade-off energetic costs of both food assimilation and

  13. Acute anti-inflammatory activity of ethanolic extract of leaves of Leucas indica by carrageenan induced paw oedema in wistar albino rats

    Directory of Open Access Journals (Sweden)

    Chandrashekar R.

    2013-06-01

    Full Text Available Background: Inflammation is basically a defense phenomenon but can lead to serious pathological conditions. It is treated by various agents with good to moderate success because of both considerable toxicity and side effects. There are various mediators to cause an inflammatory reaction that can contribute to the associated symptoms and tissue injury. Even though non steroidal anti-inflammatory drugs are the most commonly prescribed drugs in the world, their use as anti-inflammatory agents continues to be principally limited by their undesired side effects. Hence, the traditional medical practitioners and scientists are turning towards Indian System of Medicine (ISM. Methods: Dried powdered leaves of Leucas indica were subjected to solvent extraction by using 90 % ethanol. Based on acute oral toxicity study according to Organization for Economic Cooperation and Development (OECD guidelines No. 423, three doses of the test drug 75, 150 & 300mg/kg were selected and subjected to preclinical anti-inflammatory screening by carrageenin induced paw oedema in Wistar Albino rats. Results : Oral administration of Ethanolic Extract Of Leaves of Leucas Indica (EELLI at doses of 150 mg/kg and 300mg/kg showed significant anti-inflammatory activity 52.58% (p<0.01 and 36.87% (p<0.05 respectively compared to control. Conclusion: Even though oral administration of EELLI has shown significant anti-inflammatory activity, further studies are required to evaluate its comprehensive analysis including quantitative / semi quantitative analysis, characterize its chemical structure and assess its pharmacotherapeutic activities with exact mechanism of action as an anti-inflammatory agent. [Int J Basic Clin Pharmacol 2013; 2(3.000: 302-305

  14. Distribution, Abundance, Behavior, and Bioacoustics of Endangered Whales in the Western Beaufort and Northeastern Chukchi Seas, 1979-87

    Science.gov (United States)

    1988-07-01

    the area. Other Marine Mammals a. Belukha or White Whale ( Delphinapterus leucas ) Thirty-three sightings of 140 belukhas were made in the western...contour was clipped near St . Lawrence Island in the Bering Sea. Data Processing and Quality Control A computer program (SPEED) was written to screen for...Estimates 42 c. Habitat Relationships and Behavior 43 d. Calf Sightings 44 ix Page Other Marine Mammals 44 a. Belukha, or White Whale ( Delphinapterus

  15. Isolation and characterization of eight microsatellite loci from Galeocerdo cuvier (tiger shark) and cross-amplification in Carcharhinus leucas, Carcharhinus brevipinna, Carcharhinus plumbeus and Sphyrna lewini.

    Science.gov (United States)

    Pirog, Agathe; Jaquemet, Sébastien; Blaison, Antonin; Soria, Marc; Magalon, Hélène

    2016-01-01

    The tiger shark Galeocerdo cuvier (Carcharhinidae) is a large elasmobranch suspected to have, as other apex predators, a keystone function in marine ecosystems and is currently considered Near Threatened (Red list IUCN). Knowledge on its ecology, which is crucial to design proper conservation and management plans, is very scarce. Here we describe the isolation of eight polymorphic microsatellite loci using 454 GS-FLX Titanium pyrosequencing of enriched DNA libraries. Their characteristics were tested on a population of tiger shark (n = 101) from Reunion Island (South-Western Indian Ocean). All loci were polymorphic with a number of alleles ranging from two to eight. No null alleles were detected and no linkage disequilibrium was detected after Bonferroni correction. Observed and expected heterozygosities ranged from 0.03 to 0.76 and from 0.03 to 0.77, respectively. No locus deviated from Hardy-Weinberg equilibrium and the global F IS of the population was of 0.04 (NS) . Some of the eight loci developed here successfully cross-amplified in the bull shark Carcharhinus leucas (one locus), the spinner shark Carcharhinus brevipinna (four loci), the sandbar shark Carcharhinus plumbeus (five loci) and the scalloped hammerhead shark Sphyrna lewini (two loci). We also designed primers to amplify and sequence a mitochondrial marker, the control region. We sequenced 862 bp and found a low genetic diversity, with four polymorphic sites, a haplotype diversity of 0.15 and a nucleotide diversity of 2 × 10(-4).

  16. Antivenom activity of triterpenoid (C34H68O2) from Leucas aspera Linn. against Naja naja naja venom induced toxicity: antioxidant and histological study in mice.

    Science.gov (United States)

    Venkatesan, C; Sarathi, M; Balasubramanian, G; Thomas, John; Balachander, V; Babu, V Sarath; Bilal, S Mohammed Yusuf; Majeed, S Abdul; Madan, N; Raj, N Sundar; Vimal, S; Nambi, K S N; Hameed, A S Sahul

    2014-04-01

    The isolated and identified triterpenoid, 1-hydroxytetratriacontane-4-one (C34H68O2), obtained from the methanolic leaf extract of Leucas aspera Linn. was explored for the first time for antisnake venom activity. The plant (L. aspera Linn.) extract significantly antagonized the spectacled cobra (Naja naja naja) venom induced lethal activity in a mouse model. It was compared with commercial antiserum obtained from King Institute of Preventive Medicine (Chennai, Tamil Nadu, India). N. naja naja venom induced a significant decrease in antioxidant superoxide dismutase, glutathione (GSH) peroxidase, catalase, reduced GSH and glutathione-S-transferase activities and increased lipid peroxidase (LPO) activity in different organs such as heart, liver, kidney and lungs. The histological changes following the antivenom treatment were also evaluated in all these organs. There were significant alterations in the histology. Triterpenoid from methanol extract of L. aspera Linn. at a dose level of 75 mg per mouse significantly attenuated (neutralized) the venom-induced antioxidant status and also the LPO activity in different organs.

  17. Isolation of apigenin-7-O-(6’’-O-E-caffeoyl-β-D-glucopyranoside from Leucas aspera L. with anti-inflammatory and wound healing activities

    Directory of Open Access Journals (Sweden)

    Rajamanickam Manivannan

    2016-04-01

    Full Text Available Context: Leucas aspera L. (Labiatae is a common aromatic herb and grows generously in South India and in the broad area of South Asia. Traditionally, this species is taken orally for analgesic, anti-inflammatory, anti-bacterial and wound healing treatments. Aims: To isolate compounds from L. aspera with anti-inflammatory and wound healing activities. Methods: The chloroform extract was subjected to a column chromatography on silica gel 60 and their structures were established by spectral analysis (UV, IR, and NMR. The anti-inflammatory activity of the test compounds was evaluated in male albino rats. The acute inflammation was induced by the subplantar administration of 0.1 mL of 1% carrageenan in the right paw. The excision wound model was used to study the rate of wound contraction and the time required for complete epithelization of the injuries in rabbits. Results: A flavonoid apigenin-7-O-(6”-O-E-caffeoyl-β-D–glucopyrano-side (1 was isolated from a chloroform fraction of L. aspera. The hydrolysis of compound 1 yield an apigenin (aglycone, caffeic acid and β-D-glucose. Assuming caffeoyl glucose linked to the 7-OH group of apigenin. Conclusions: Compound 1 exhibited a significant anti-inflammatory activity compared with standard diclofenac sodium. The wound healing study revealed that decreased wound area and significant increase in epithelialization in treatment groups was observed.

  18. Comparative feeding ecology of bull sharks (Carcharhinus leucas) in the coastal waters of the southwest Indian Ocean inferred from stable isotope analysis.

    Science.gov (United States)

    Daly, Ryan; Froneman, Pierre W; Smale, Malcolm J

    2013-01-01

    As apex predators, sharks play an important role shaping their respective marine communities through predation and associated risk effects. Understanding the predatory dynamics of sharks within communities is, therefore, necessary to establish effective ecologically based conservation strategies. We employed non-lethal sampling methods to investigate the feeding ecology of bull sharks (Carcharhinus leucas) using stable isotope analysis within a subtropical marine community in the southwest Indian Ocean. The main objectives of this study were to investigate and compare the predatory role that sub-adult and adult bull sharks play within a top predatory teleost fish community. Bull sharks had significantly broader niche widths compared to top predatory teleost assemblages with a wide and relatively enriched range of δ(13)C values relative to the local marine community. This suggests that bull sharks forage from a more diverse range of δ(13)C sources over a wider geographical range than the predatory teleost community. Adult bull sharks appeared to exhibit a shift towards consistently higher trophic level prey from an expanded foraging range compared to sub-adults, possibly due to increased mobility linked with size. Although predatory teleost fish are also capable of substantial migrations, bull sharks may have the ability to exploit a more diverse range of habitats and appeared to prey on a wider diversity of larger prey. This suggests that bull sharks play an important predatory role within their respective marine communities and adult sharks in particular may shape and link ecological processes of a variety of marine communities over a broad range.

  19. Investigation of the Molecular Response of Belugas to Stressors

    Science.gov (United States)

    2014-09-30

    described above were obtained from this related project. REFERENCES Denis, F., Archambault, D., 2001. Molecular cloning and characterization of...mRNA expression levels serve as indicators to assess stress? BMC Veterinary Research 9:145. St-Laurent, G. and Archambault, D., 2000. Molecular ... cloning , phylogenetic analysis and expression of beluga whale (Delphinapterus leucas) interleukin 6. Veterinary Immunology Immunopathology 73: 31-44

  20. Estimating the Economic Value of Narwhal and Beluga Hunts in Hudson Bay, Nunavut

    NARCIS (Netherlands)

    Hoover, C.; Bailey, M.L.; Higdon, J.; Ferguson, S.H.; Sumaila, R.

    2013-01-01

    Hunting of narwhal (Monodon monoceros) and beluga (Delphinapterus leucas) in Hudson Bay is an important activity, providing food and income in northern communities, yet few studies detail the economic aspects of these hunts. We outline the uses of narwhal and beluga and estimate the revenues, costs,

  1. 75 FR 54599 - Takes of Marine Mammals Incidental to Specified Activities; Construction of the Knik Arm Crossing...

    Science.gov (United States)

    2010-09-08

    ... Act (MMPA), NMFS is announcing receipt of the KABATA's application and request for the development and... through 2017. Marine mammals, particularly Cook Inlet beluga whales (Delphinapterus leucas), would be... Level B harassment, Cook Inlet beluga whales, harbor seals (Phoca vitulina), harbor porpoise...

  2. 75 FR 4528 - Endangered and Threatened Species: Notice of Intent to Prepare a Recovery Plan for Cook Inlet...

    Science.gov (United States)

    2010-01-28

    ... plan development. NMFS is hereby soliciting relevant information on Cook Inlet beluga whales and their... Intent to Prepare a Recovery Plan for Cook Inlet Beluga Whales AGENCY: National Marine Fisheries Service... recovery plan for the Cook Inlet beluga whale (Delphinapterus leucas) and requests information from...

  3. 77 FR 27283 - Takes of Marine Mammals Incidental to Specified Activities; Taking Marine Mammals Incidental to...

    Science.gov (United States)

    2012-05-09

    ... in Camden Bay. These species include: beluga whale (Delphinapterus leucas); bowhead whale (Balaena... notes reactions of bowhead and beluga whales to certain activities below 160 dB. The letter also states... causing disruption of behavioral patterns, including, but not limited to, migration, breathing,...

  4. 77 FR 50473 - Taking of Marine Mammals Incidental to Specified Activities; Construction of the East Span of the...

    Science.gov (United States)

    2012-08-21

    ... Project History Construction activities for the replacement of the east span of the SF-OBB commenced in... case the loss of hearing sensitivity is unrecoverable, or temporary (TTS), in which case the animal's..., experiments on a bottlenose dolphin (Tursiops truncates) and beluga whale (Delphinapterus leucas) showed that...

  5. Population Structure of Island-Associated Dolphins: Evidence from Mitochondrial and Microsatellite Markers for Common Bottlenose Dolphins (Tursiops truncatus) Around the Main Hawaiian Islands

    Science.gov (United States)

    2011-01-01

    derived from killer whales (Orcinus orca ; Hoelzel et al. 1998a); loci D5 and D12 from beluga whales (Delphinapterus leucas; Buchanan et al. 1996); and...M. Dahlheim and S. J. Stern. 1998a. Low genetic variation among killer whales (Orcinus orca ) in the eastern North Pacific and genetic...24 MARINE MAMMAL SCIENCE, VOL. **, NO. **, 2011 Rooney, A. P., D. B.Merritt and J.N.Derr. 1999.Microsatellite diversity in captive bottlenose dolphins

  6. Sound Propagation in Shallow Water. Volume 2. Unclassified Papers

    Science.gov (United States)

    1974-11-15

    sounds generated either by beluga whales [Ref. 24J or by any other marine mammal indigenous to the Bering Sea [Ref. 25]. Beluga whales migrate ...34, "chirping" and "whistling" were recorded near the ice/water boundary predominantly at site I, and to some extent at sites Da and D«* Beluga whales ...34Production of Underwater Sound by the White Whale or Beluga , Delphinapterus leucas (Pallas), "Journal of Marine Research, 20(2), 149-162 (1962

  7. A Synopsis of Marine Animal Underwater Sounds in Eight Geographic Areas

    Science.gov (United States)

    1971-05-28

    34. Since then we have found that migrating gray whales produce moans, under- water sounds associated with their blows, and knocking sounds. Moans last...the whales are in a given area, usually as they migrate past, between their summer sojourns to polar waters and their winter movements toward the...its vocali- zations are available from Dr. W. C. Cummings, NUC Code 5054. : ii V, , 71 Delphinapterus leucas--(white- whale or beluga ) The beluga is

  8. Aerial Surveys of Endangered Whales in the Beaufort Sea, Chukchi Sea, and Northern Bering Sea.

    Science.gov (United States)

    1981-06-01

    16 Surveys of St Lawrence Island Nome to Point Barrow . . . 16 I Surveys of Barrow Area . . 18 Point Barrow to Deadhorse . . . 20 Surveys from...lease area, the Norton Basin - St . Lawrence Island area, the Hope Basin, and coastal portions of the Chukchi Sea. DESIGN The areas of study are listed...Bowhead Whale 314 857 Balaena mysticetus Beluga Whale** 284 3404 Delphinapterus leucas Gray Whale 2 6 Eschrichtius robustus Ring Seal 250 765 Phoca

  9. Cancer in wildlife, a case study: beluga from the St. Lawrence estuary, Québec, Canada.

    OpenAIRE

    Martineau, Daniel; Lemberger, Karin; Dallaire, André; Labelle, Philippe; Lipscomb, Thomas P; Michel, Pascal; Mikaelian, Igor

    2002-01-01

    A population of approximately 650 beluga (Delphinapterus leucas) inhabits a short segment of the St. Lawrence estuary (SLE). Over 17 years (1983-1999), we have examined 129 (or 49%) of 263 SLE beluga carcasses reported stranded. The major primary causes of death were respiratory and gastrointestinal infections with metazoan parasites (22%), cancer (18%), and bacterial, viral, and protozoan infections (17%). We observed cancer in 27% of examined adult animals found dead, a percentage similar t...

  10. Strategic Investment Plan Fiscal Year 1993.

    Science.gov (United States)

    1993-09-01

    health of world oceans. The beluga whale ( Delphinapterus leucas ) has received increasing attention with respect to environmental contaminants. One...population in particular, that of the St . Lawrence River and Estuary in Quebec, Canada, is now suspected to be severely impacted by a variety of industrial...evidence is mounting that the health of the St . Lawrence population is being measurably threatened when compared to belugas in other Canadian regions

  11. The beluga whale produces two pulses to form its sonar signal

    OpenAIRE

    Lammers, Marc O.; CASTELLOTE Manuel

    2009-01-01

    Odontocete cetaceans use biosonar clicks to acoustically probe their aquatic environment with an aptitude unmatched by man-made sonar. A cornerstone of this ability is their use of short, broadband pulses produced in the region of the upper nasal passages. Here we provide empirical evidence that a beluga whale (Delphinapterus leucas) uses two signal generators simultaneously when echolocating. We show that the pulses of the two generators are combined as they are transmitted through the melon...

  12. Effects of Aircraft Noise and Sonic Booms on Domestic Animals and Wildlife: A Literature Synthesis

    Science.gov (United States)

    1988-06-01

    Aquatic mammals: Beluga whale Boat traffic (Acoustical Easily displaced Society of America 1980) Pinnepeds Sonic booms (80-89 dBA SPL) Startle...Arctic mammals are limited. Beluga whales (Delphinapterus leucas) are more easily displaced by boat traffic when feeding, and bowhead whales (Balaena...population of ravens (Corvus corax) to a sonic boom in central Wales Three or four ravens were idling in the upcurrents over a high rock spur between

  13. Detection, Classification, and Density Estimation of Marine Mammals

    Science.gov (United States)

    2012-10-01

    beluga and bowhead whale recordings from the Beaufort Sea NOAA-NMML – recordings of many species from the Bering Sea Univ. New South Wales ...whale Antarctic 8594 3 8432.1 Univ. New S. Wales Berardius bairdii Baird’s beaked whale North Pacific 18 7797.1 UW-APL, NMML/NOAA northeast Pacific...Waves, Inc. northeast Alaska Independent researcher Delphinapterus leucas beluga Chukchi Sea Bio-Waves, Inc. St. Lawrence Estuary

  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. Stable isotopes (δ 18O and δ 13C), trace and minor element compositions of Recent scleractinians and Last Glacial bivalves at the Santa Maria di Leuca deep-water coral province, Ionian Sea

    Science.gov (United States)

    Correa, Matthias López; Montagna, Paolo; Vendrell-Simón, Begoña; McCulloch, Malcolm; Taviani, Marco

    2010-03-01

    The aragonitic skeletons of bathyal cold-water corals have a high potential as geochemical in situ archives for paleoceanography. Oxygen isotopes and stable carbon isotopes (δ 18O and δ 13C) have been analyzed, as well as trace and minor element compositions (e.g. Mg/Ca, Sr/Ca, U/Ca, B/Ca and P/Ca) in Lophelia pertusa, one of the most important frame-builders at the Santa Maria di Leuca (SML) deep-water coral hotspot in the Central Mediterranean. The Apulian Bank is swept by strong currents of the Adriatic Deep Water Outflow. The temperature of 13.9 °C is the highest temperature recorded for L. pertusa and provides an important end-member of environmental conditions for geochemical analyses on living Atlantic and Mediterranean cold-water corals. Temperature and salinity (38.77 PSU) are stable throughout the year, and thus virtually no changes should be observed in the stable oxygen isotope signal—if the coral precipitates its skeleton in equilibrium with seawater. We measured various marine properties, such as the seawater oxygen isotope composition (δ 18O sw), stable carbon isotope composition (δ 13C DIC) of dissolved inorganic carbon (DIC), and dissolved inorganic nutrient concentrations (PO 4, NO 3, NO 2, NH 3 and SiO 2). Bottom water at the coral sites shows a mean oxygen isotope composition of 1.47‰ δ 18O sw-VSMOW, and δ 13C DIC showed a mean of 1.1‰ VPDB. A section of a living L. pertusa with a thick theca calcification was probed with a Merchantek MicroMill at a high spatial sampling resolution with 10 samples per 1 mm. This reduced the signal-smoothing inherent to conventional sampling. The δ 18O ag of coral aragonite ranges between -2.0‰ and +2.8‰ VPDB and the δ 13C ag ranges between -7.77‰ and +1.47‰ VPDB. The Gaussian data distribution for both parameters, including heavy equilibrium values, suggests the completeness of the captured isotopic variability. The strict linear correlation of δ 13C and δ 18O displays a strong 'kinetic

  16. Hard electronics; Hard electronics

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-03-01

    In the fields of power conversion devices and broadcasting/communication amplifiers, high power, high frequency and low losses are desirable. Further, for electronic elements in aerospace/aeronautical/geothermal surveys, etc., heat resistance to 500degC is required. Devices which respond to such hard specifications are called hard electronic devices. However, with Si which is at the core of the present electronics, the specifications cannot fully be fulfilled because of the restrictions arising from physical values. Accordingly, taking up new device materials/structures necessary to construct hard electronics, technologies to develop these to a level of IC were examined and studied. They are a technology to make devices/IC of new semiconductors such as SiC, diamond, etc. which can handle higher temperature, higher power and higher frequency than Si and also is possible of reducing losses, a technology to make devices of hard semiconducter materials such as a vacuum microelectronics technology using ultra-micro/high-luminance electronic emitter using negative electron affinity which diamond, etc. have, a technology to make devices of oxides which have various electric properties, etc. 321 refs., 194 figs., 8 tabs.

  17. Electronic Cigarettes

    Science.gov (United States)

    ... New FDA Regulations Text Size: A A A Electronic Cigarettes Electronic cigarettes (e-cigarettes) are battery operated products designed ... more about: The latest news and events about electronic cigarettes on this FDA page Electronic cigarette basics ...

  18. 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.

  19. 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.

  20. Ambient Electronics

    Science.gov (United States)

    Sekitani, Tsuyoshi; Someya, Takao

    2012-10-01

    We report the recent research progress and future prospects of flexible and printed electronics, focusing on molecular electronic material-based thin-film transistors, which are expected to usher in a new era of electronics.

  1. Electron cooling

    Science.gov (United States)

    Meshkov, I.; Sidorin, A.

    2004-10-01

    The brief review of the most significant and interesting achievements in electron cooling method, which took place during last two years, is presented. The description of the electron cooling facilities-storage rings and traps being in operation or under development-is given. The applications of the electron cooling method are considered. The following modern fields of the method development are discussed: crystalline beam formation, expansion into middle and high energy electron cooling (the Fermilab Recycler Electron Cooler, the BNL cooler-recuperator, cooling with circulating electron beam, the GSI project), electron cooling in traps, antihydrogen generation, electron cooling of positrons (the LEPTA project).

  2. Auditory Weighting Functions and TTS/PTS Exposure Functions for Marine Mammals Exposed to Underwater Noise

    Science.gov (United States)

    2016-12-01

    In-air and Underwater Hearing Sensitivity of a Northern Elephant Seal (Mirounga Angustirostris),” Canadian Journal of Zoology 77:1751–1758. Kastak...Pulses,” Canadian Journal of Zoology 66:1578– 1582. 59 Thomas, J., N. Chun, W. Au, and K. Pugh. 1988. “Underwater Audiogram of a False Killer...Underwater Hearing Sensitivity In Belugas, Delphinapterus leucas,” Journal of the Acoustical Society of America 84:2273–2275. Babushina, E. S., G. L

  3. Genetic profiling links changing sea-ice to shifting beluga whale migration patterns

    OpenAIRE

    2016-01-01

    There is increasing concern over how Arctic fauna will adapt to climate related changes in sea-ice. We used long-term sighting and genetic data on beluga whales (Delphinapterus leucas) in conjunction with multi-decadal patterns of sea-ice in the Pacific Arctic to investigate the influence of sea-ice on spring migration and summer residency patterns. Substantial variations in sea-ice conditions were detected across seasons, years and sub-regions, revealing ice–ocean dynamics more complex than ...

  4. Status of the belugas of the St Lawrence estuary, Canada

    OpenAIRE

    Michael CS Kingsley

    2002-01-01

    A population of belugas (Delphinapterus leucas) inhabiting the estuary of the St Lawrence river in Quebec, Canada, was depleted by unregulated hunting, not closed until 1979. Surveys in 1977 showed only a few hundred in the population. Surveys since then have produced increasing estimates of population indices. An estimate of the population, fully corrected for diving animals, was 1,238 (SE 119) in September 1997. The population was estimated to have increased from 1988 through 1997 by 31.4 b...

  5. Uterine adenocarcinoma with abdominal carcinomatosis in a beluga whale.

    Science.gov (United States)

    Lair, S; De Guise, S; Martineau, D

    1998-04-01

    A case of uterine adenocarcinoma is reported in a 26-yr-old, free-ranging beluga whale (Delphinapterus leucas) from the St. Lawrence estuary (Quebec, Canada). This neoplasm appeared as a segmental stenotic thickening of the left uterine horn composed of well differentiated, but disorganized and infiltrative, glandular structures surrounded by an extensive scirrhous stroma. Abdominal carcinomatosis was observed on the mesosalpinx and on the serosal aspect of the gastric compartments. This is the first report of a malignancy originating in the uterus of a cetacean.

  6. Visibility of St Lawrence belugas to aerial photography, estimated by direct observation

    OpenAIRE

    Michael CS Kingsley; Isabelle Gauthier

    2002-01-01

    The depleted population of belugas (Delphinapterus leucas) inhabiting the St Lawrence estuary, Canada, was monitored by periodic photographic aerial surveys. In order to correct counts made on aerial survey film and to obtain an estimate of the true size of the population, the diving behaviour and the visibility from the air of these animals was studied. A Secchi-disk turbidity survey in the belugas’ summer range showed that water clarity varied between 1.5 m and 11.6 m. By studying aerial ph...

  7. Electron Microscopy.

    Science.gov (United States)

    Beer, Michael

    1980-01-01

    Reviews technical aspects of structure determination in biological electron microscopy (EM). Discusses low dose EM, low temperature microscopy, electron energy loss spectra, determination of mass or molecular weight, and EM of labeled systems. Cites 34 references. (CS)

  8. Electron Microscopy.

    Science.gov (United States)

    Beer, Michael

    1980-01-01

    Reviews technical aspects of structure determination in biological electron microscopy (EM). Discusses low dose EM, low temperature microscopy, electron energy loss spectra, determination of mass or molecular weight, and EM of labeled systems. Cites 34 references. (CS)

  9. 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.

  10. 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

  11. Electronic Prescribing

    Science.gov (United States)

    ... Do you prescribe electronically?” For more information about electronic prescribing, call 1-800-MEDICARE (1-800-633- ... TTY users should call 1-877-486-2048 . Electronic eRx Prescribing I went to the pharmacy, and ...

  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. 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 P

  14. 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....

  15. 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....

  16. 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.

  17. Micropower electronics

    CERN Document Server

    Keonjian, Edward

    1964-01-01

    Micropower Electronics deals with the operation of modern electronic equipment at micropower levels and the problems associated with micropower electronics. Topics covered include the relations between minimum required power density and frequency response for semiconductor triode amplifiers; physical realization of digital logic circuits; micropower microelectronic subsystems; and metal-oxide-semiconductor field-effect devices for micropower logic circuitry. This book is comprised of 10 chapters and begins with an analysis of fundamental relationships and basic requirements pertinent to the ph

  18. 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.

  19. 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.

  20. 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

  1. 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

  2. Electronic Photography

    Science.gov (United States)

    Payne, Meredith Lindsay

    1995-01-01

    The main objective was to assist in the production of electronic images in the Electronic Photography Lab (EPL). The EPL is a new facility serving the electronic photographic needs of the Langley community. The purpose of the Electronic Photography lab is to provide Langley with access to digital imaging technology. Although the EPL has been in operation for less than one year, almost 1,000 images have been produced. The decision to establish the lab was made after careful determination of the centers needs for electronic photography. The LaRC community requires electronic photography for the production of electronic printing, Web sites, desktop publications, and its increased enhancement capabilities. In addition to general use, other considerations went into the planning of the EPL. For example, electronic photography is much less of a burden on the environment compared to conventional photography. Also, the possibilities of an on-line database and retrieval system could make locating past work more efficient. Finally, information in an electronic image is quantified, making measurements and calculations easier for the researcher.

  3. Electron Bifurcation

    Energy Technology Data Exchange (ETDEWEB)

    Peters, John W.; Miller, Anne-Frances; Jones, Anne K.; King, Paul W.; Adams, Michael W. W.

    2016-04-01

    Electron bifurcation is the recently recognized third mechanism of biological energy conservation. It simultaneously couples exergonic and endergonic oxidation-reduction reactions to circumvent thermodynamic barriers and minimize free energy loss. Little is known about the details of how electron bifurcating enzymes function, but specifics are beginning to emerge for several bifurcating enzymes. To date, those characterized contain a collection of redox cofactors including flavins and iron-sulfur clusters. Here we discuss the current understanding of bifurcating enzymes and the mechanistic features required to reversibly partition multiple electrons from a single redox site into exergonic and endergonic electron transfer paths.

  4. Printed Electronics

    Science.gov (United States)

    Crain, John M. (Inventor); Lettow, John S. (Inventor); Aksay, Ilhan A. (Inventor); Korkut, Sibel (Inventor); Chiang, Katherine S. (Inventor); Chen, Chuan-Hua (Inventor); Prud'Homme, Robert K. (Inventor)

    2016-01-01

    Printed electronic device comprising a substrate onto at least one surface of which has been applied a layer of an electrically conductive ink comprising functionalized graphene sheets and at least one binder. A method of preparing printed electronic devices is further disclosed.

  5. Electron optics

    CERN Document Server

    Grivet, Pierre; Bertein, F; Castaing, R; Gauzit, M; Septier, Albert L

    1972-01-01

    Electron Optics, Second English Edition, Part I: Optics is a 10-chapter book that begins by elucidating the fundamental features and basic techniques of electron optics, as well as the distribution of potential and field in electrostatic lenses. This book then explains the field distribution in magnetic lenses; the optical properties of electrostatic and magnetic lenses; and the similarities and differences between glass optics and electron optics. Subsequent chapters focus on lens defects; some electrostatic lenses and triode guns; and magnetic lens models. The strong focusing lenses and pris

  6. Electronic diagrams

    CERN Document Server

    Colwell, Morris A

    1976-01-01

    Electronic Diagrams is a ready reference and general guide to systems and circuit planning and in the preparation of diagrams for both newcomers and the more experienced. This book presents guidelines and logical procedures that the reader can follow and then be equipped to tackle large complex diagrams by recognition of characteristic 'building blocks' or 'black boxes'. The goal is to break down many of the barriers that often seem to deter students and laymen in learning the art of electronics, especially when they take up electronics as a spare time occupation. This text is comprised of nin

  7. Digital electronics

    CERN Document Server

    Morris, John

    2013-01-01

    An essential companion to John C Morris's 'Analogue Electronics', this clear and accessible text is designed for electronics students, teachers and enthusiasts who already have a basic understanding of electronics, and who wish to develop their knowledge of digital techniques and applications. Employing a discovery-based approach, the author covers fundamental theory before going on to develop an appreciation of logic networks, integrated circuit applications and analogue-digital conversion. A section on digital fault finding and useful ic data sheets completes th

  8. Electronic identity

    CERN Document Server

    de Andrade, Norberto Nuno Gomes; Argles, David

    2014-01-01

    With the increasing availability of electronic services, security and a reliable means by which identity is verified is essential.Written by Norberto Andrade the first chapter of this book provides an overview of the main legal and regulatory aspects regarding electronic identity in Europe and assesses the importance of electronic identity for administration (public), business (private) and, above all, citizens. It also highlights the role of eID as a key enabler of the economy.In the second chapter Lisha Chen-Wilson, David Argles, Michele Schiano di Zenise and Gary Wills discuss the user-cent

  9. Stretchable electronics

    CERN Document Server

    Someya, Takao

    2012-01-01

    With its comprehensive coverage this handbook and ready reference brings together some of the most outstanding scientists in the field to lay down the undisputed knowledge on how to make electronics stretchable.As such, it focuses on gathering and evaluating the materials, designs, models and technologies that enable the fabrication of fully elastic electronic devices which can sustain high strain. Furthermore, it provides a review of those specific applications that directly benefit from highly compliant electronics, including transistors, photonic devices and sensors. In addition to stre

  10. Starting electronics

    CERN Document Server

    Brindley, Keith

    2005-01-01

    Starting Electronics is unrivalled as a highly practical introduction for hobbyists, students and technicians. Keith Brindley introduces readers to the functions of the main component types, their uses, and the basic principles of building and designing electronic circuits. Breadboard layouts make this very much a ready-to-run book for the experimenter; and the use of multimeter, but not oscilloscopes, puts this practical exploration of electronics within reach of every home enthusiast's pocket. The third edition has kept the simplicity and clarity of the original. New material

  11. Polymer electronics

    CERN Document Server

    Geoghegan, Mark

    2013-01-01

    Polymer electronics is the science behind many important new developments in technology, such as the flexible electronic display (e-ink) and many new developments in transistor technology. Solar cells, light-emitting diodes, and transistors are all areas where plastic electronics is likely to, or is already having, a serious impact on our daily lives. With polymer transistors and light-emitting diodes now being commercialised, there is a clear need for a pedagogic text thatdiscusses the subject in a clear and concise fashion suitable for senior undergraduate and graduate students. The content

  12. 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....

  13. 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....

  14. Electronic plants

    Science.gov (United States)

    Stavrinidou, Eleni; Gabrielsson, Roger; Gomez, Eliot; Crispin, Xavier; Nilsson, Ove; Simon, Daniel T.; Berggren, Magnus

    2015-01-01

    The roots, stems, leaves, and vascular circuitry of higher plants are responsible for conveying the chemical signals that regulate growth and functions. From a certain perspective, these features are analogous to the contacts, interconnections, devices, and wires of discrete and integrated electronic circuits. Although many attempts have been made to augment plant function with electroactive materials, plants’ “circuitry” has never been directly merged with electronics. We report analog and digital organic electronic circuits and devices manufactured in living plants. The four key components of a circuit have been achieved using the xylem, leaves, veins, and signals of the plant as the template and integral part of the circuit elements and functions. With integrated and distributed electronics in plants, one can envisage a range of applications including precision recording and regulation of physiology, energy harvesting from photosynthesis, and alternatives to genetic modification for plant optimization. PMID:26702448

  15. ELECTRONIC SIGNATURES

    African Journals Online (AJOL)

    10332324

    'electronic signature' means data attached to, incorporated in, or logically ... See Cwele v S 2012 4 All SA 497 (SCA); Mohlabeng v Minister of Safety and Security ... ZAKZPHC 51 (2 September 2010); Delta Finance, a Division of Wesbank, ...

  16. Electron Microprobe

    Data.gov (United States)

    Federal Laboratory Consortium — The JEOL JXA-8600 is a conventional hairpin filament thermal emission electron microprobe that is more than 20 years old. It is capable of performing qualitative and...

  17. Electronic commerce

    OpenAIRE

    Veselková, Zdeňka

    2012-01-01

    The thesis deals with a description of electronic commerce from its beginning up to present situation in this area. It explains basic terms connected with electronic commerce and it summarizes the relevant legislation. Moreover it describes e-contracts and rights and duties of both contractual parties. The main view is the view of Internet retailer, which is reflected in the practical part focused on concrete problems of retailers.

  18. Molecular Electronics

    DEFF Research Database (Denmark)

    Jennum, Karsten Stein

    This thesis includes the synthesis and characterisation of organic compounds designed for molecular electronics. The synthesised organic molecules are mainly based on two motifs, the obigo(phenyleneethynylenes) (OPE)s and tetrathiafulvalene (TTF) as shown below. These two scaffolds (OPE and TTF......) are chemically merged together to form cruciform-like structures that are an essential part of the thesis. The cruciform molecules were subjected to molecular conductance measurements to explore their capability towards single-crystal field-effect transistors (Part 1), molecular wires, and single electron......, however, was obtained by a study of a single molecular transistor. The investigated OPE5-TTF compound was captured in a three-terminal experiment, whereby manipulation of the molecule’s electronic spin was possible in different charge states. Thus, we demonstrated how the cruciform molecules could...

  19. Power Electronics

    DEFF Research Database (Denmark)

    Iov, Florin; Ciobotaru, Mihai; Blaabjerg, Frede

    2008-01-01

    energy at the end-user should also be set up. Deregulation of energy has in the past lowered the investment in larger power plants, which means the need for new electrical power sources will be high in the near future. Two major technologies will play important roles to solve the future problems. One...... 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...

  20. Electron Spectroscopy

    Science.gov (United States)

    Siegbahn, Kai

    Wilhelm Conrad Röntgen's discovery of X radiation in 1895 in Wörzburg resulted in an immediate break-through not only in physics but also in Society, the latter mainly because of its sensational radiological applications. Within a short time it furthermore indirectly led to the discovery of radioactivity by Henri Becquerel. The discovery of X radiation opened the gate to modern atomic physics, and radioactivity to nuclear physics. Later on, the discovery of X-ray diffraction by Laue, Friedrich and Knipping in 1912 initiated the field of X-ray spectroscopy with its fundamental contributions to atomic and crystal structures. Secondary electrons were early observed in the scattered radiation when X-rays were hitting a sample. The development of the corresponding electron spectroscopy had to wait a much longer time for its maturity. A survey of electron spectroscopy is presented.

  1. Electronic Commerce

    Energy Technology Data Exchange (ETDEWEB)

    Laird, N. [NRG Information Services Inc., Calgary, AB (Canada)

    1995-11-01

    The concept of electronic commerce in the gas industry was discussed. It was defined as the integration of communication technology, advanced information processing capability and business standards, to improve effectiveness of the business process. Examples of electronic data interchange from the automotive, airline, and banking industry were given. The objective of using this technology in the gas industry was described as the provision of one electronic facility to make seamless contractual and operational arrangements for moving natural gas across participating pipelines. The benefit of seamless integration - one readily available standard system used by several companies - was highlighted. A list of value-added services such as the free movement of bulletins, directories, nominations,and other documents was provided.

  2. Spin electronics

    CERN Document Server

    Buhrman, Robert; Daughton, James; Molnár, Stephan; Roukes, Michael

    2004-01-01

    This report is a comparative review of spin electronics ("spintronics") research and development activities in the United States, Japan, and Western Europe conducted by a panel of leading U.S. experts in the field. It covers materials, fabrication and characterization of magnetic nanostructures, magnetism and spin control in magnetic nanostructures, magneto-optical properties of semiconductors, and magnetoelectronics and devices. The panel's conclusions are based on a literature review and a series of site visits to leading spin electronics research centers in Japan and Western Europe. The panel found that Japan is clearly the world leader in new material synthesis and characterization; it is also a leader in magneto-optical properties of semiconductor devices. Europe is strong in theory pertaining to spin electronics, including injection device structures such as tunneling devices, and band structure predictions of materials properties, and in development of magnetic semiconductors and semiconductor heterost...

  3. Molecular Electronics

    DEFF Research Database (Denmark)

    Jennum, Karsten Stein

    ) are chemically merged together to form cruciform-like structures that are an essential part of the thesis. The cruciform molecules were subjected to molecular conductance measurements to explore their capability towards single-crystal field-effect transistors (Part 1), molecular wires, and single electron......This thesis includes the synthesis and characterisation of organic compounds designed for molecular electronics. The synthesised organic molecules are mainly based on two motifs, the obigo(phenyleneethynylenes) (OPE)s and tetrathiafulvalene (TTF) as shown below. These two scaffolds (OPE and TTF......, however, was obtained by a study of a single molecular transistor. The investigated OPE5-TTF compound was captured in a three-terminal experiment, whereby manipulation of the molecule’s electronic spin was possible in different charge states. Thus, we demonstrated how the cruciform molecules could...

  4. Greening Electronics

    DEFF Research Database (Denmark)

    Pizzol, Massimo; Søes Kokborg, Morten; Thomsen, Marianne

    Based on a literature review with focus on hazardous substances in waste electric and electronic equipment (WEEE) and numbers from a Danish treatment facility a flow analysis for specific substances has been conducted. Further, the accessible knowledge on human and environmental effects due...

  5. Superconducting electronics

    NARCIS (Netherlands)

    Rogalla, Horst

    1994-01-01

    During the last decades superconducting electronics has been the most prominent area of research for small scale applications of superconductivity. It has experienced quite a stormy development, from individual low frequency devices to devices with high integration density and pico second switching

  6. Electronic Portfolios.

    Science.gov (United States)

    Purves, Alan C.

    1996-01-01

    Outlines three forms of electronic portfolio based on a student's work, a class project about a specific topic, and a class seminar on a broad topic. Discusses logistical problems of management, access, and cross-referencing; technical problems of input, access, and copying; and theoretical issues of the lack of realia, of ownership and copyright,…

  7. Electronic Money.

    Science.gov (United States)

    Schilling, Tim

    Thirty years ago a cashless society was predicted for the near future; paper currency and checks would be an antiquated symbol of the past. Consumers would embrace a new alternative for making payments: electronic money. But currency is still used for 87% of payments, mainly for "nickel and dime" purchases. And checks are the payment…

  8. Electronic spectroscopies

    NARCIS (Netherlands)

    Weckhuysen, B.M.; Schoonheydt, R.A.

    2000-01-01

    Diffuse reflectance spectroscopy (DRS) in the ultraviolet, visible and near-infrared region is a versatile spectroscopic technique, as both d-d and charge transfer transitions of supported TMI can be probed. One of the advantages of electronic spectroscopy is that the obtained information is

  9. Electronic Homework.

    Science.gov (United States)

    Lee, Fong-lok; Heyworth, Rex M.

    The Electronic Homework assistant system is composed of two components: the Computer Tutor and the Homework Administrator. The Computer Tutor is an intelligent tutoring system that can provide personal assistance like supplying hints, checking errors, providing remediation and prioritizing problems. The Homework Administrator is a teacher's…

  10. Greening Electronics

    DEFF Research Database (Denmark)

    Pizzol, Massimo; Søes Kokborg, Morten; Thomsen, Marianne

    Based on a literature review with focus on hazardous substances in waste electric and electronic equipment (WEEE) and numbers from a Danish treatment facility a flow analysis for specific substances has been conducted. Further, the accessible knowledge on human and environmental effects due to po...

  11. Electronic Government

    DEFF Research Database (Denmark)

    Wimmer, Maria A.; Traunmüller, Roland; Grönlund, Åke

    This book constitutes the refereed proceedings of the 4th International Conference on Electronic Government, EGOV 2005, held in Copenhagen, Denmark, in August 2005. The 30 revised papers presented were carefully reviewed and selected from numerous submissions, and assess the state-of-the-art in e...

  12. Electronic detectors for electron microscopy.

    Science.gov (United States)

    Faruqi, A R; McMullan, G

    2011-08-01

    Electron microscopy (EM) is an important tool for high-resolution structure determination in applications ranging from condensed matter to biology. Electronic detectors are now used in most applications in EM as they offer convenience and immediate feedback that is not possible with film or image plates. The earliest forms of electronic detector used routinely in transmission electron microscopy (TEM) were charge coupled devices (CCDs) and for many applications these remain perfectly adequate. There are however applications, such as the study of radiation-sensitive biological samples, where film is still used and improved detectors would be of great value. The emphasis in this review is therefore on detectors for use in such applications. Two of the most promising candidates for improved detection are: monolithic active pixel sensors (MAPS) and hybrid pixel detectors (of which Medipix2 was chosen for this study). From the studies described in this review, a back-thinned MAPS detector appears well suited to replace film in for the study of radiation-sensitive samples at 300 keV, while Medipix2 is suited to use at lower energies and especially in situations with very low count rates. The performance of a detector depends on the energy of electrons to be recorded, which in turn is dependent on the application it is being used for; results are described for a wide range of electron energies ranging from 40 to 300 keV. The basic properties of detectors are discussed in terms of their modulation transfer function (MTF) and detective quantum efficiency (DQE) as a function of spatial frequency.

  13. Electronic Aggression

    Centers for Disease Control (CDC) Podcasts

    2007-11-20

    Aggression is no longer limited to the school yard. New forms of electronic media, such as blogs, instant messaging, chat rooms, email, text messaging, and the internet are providing new arenas for youth violence to occur.  Created: 11/20/2007 by National Center for Injury Prevention and Control, Division of Violence Prevention.   Date Released: 11/28/2007.

  14. Interacting Electrons

    Science.gov (United States)

    Martin, Richard M.; Reining, Lucia; Ceperley, David M.

    2016-06-01

    Preface; Part I. Interacting Electrons: Beyond the Independent-Particle Picture: 1. The many electron problem: introduction; 2. Signatures of electron correlation; 3. Concepts and models for interacting electrons; Part II. Foundations of Theory for Many-Body Systems: 4. Mean fields and auxiliary systems; 5. Correlation functions; 6. Many-body wavefunctions; 7. Particles and quasi-particles; 8. Functionals in many-particle physics; Part III. Many-Body Green's Function Methods: 9. Many-body perturbation theory: expansion in the interaction; 10. Many-body perturbation theory via functional derivatives; 11. The RPA and the GW approximation for the self-energy; 12. GWA calculations in practice; 13. GWA calculations: illustrative results; 14. RPA and beyond: the Bethe-Salpeter equation; 15. Beyond the GW approximation; 16. Dynamical mean field theory; 17. Beyond the single-site approximation in DMFT; 18. Solvers for embedded systems; 19. Characteristic hamiltonians for solids with d and f states; 20. Examples of calculations for solids with d and f states; 21. Combining Green's functions approaches: an outlook; Part IV. Stochastic Methods: 22. Introduction to stochastic methods; 23. Variational Monte Carlo; 24. Projector quantum Monte Carlo; 25. Path integral Monte Carlo; 26. Concluding remarks; Part V. Appendices: A. Second quantization; B. Pictures; C. Green's functions: general properties; D. Matsubara formulation for Green's functions for T ̸= 0; E. Time-ordering, contours, and non-equilibrium; F. Hedin's equations in a basis; G. Unique solutions in Green's function theory; H. Properties of functionals; I. Auxiliary systems and constrained search; J. Derivation of the Luttinger theorem; K. Gutzwiller and Hubbard approaches; References; Index.

  15. ELECTRON GUN

    Science.gov (United States)

    Christofilos, N.C.; Ehlers, K.W.

    1960-04-01

    A pulsed electron gun capable of delivering pulses at voltages of the order of 1 mv and currents of the order of 100 amperes is described. The principal novelty resides in a transformer construction which is disposed in the same vacuum housing as the electron source and accelerating electrode structure of the gun to supply the accelerating potential thereto. The transformer is provided by a plurality of magnetic cores disposed in circumferentially spaced relation and having a plurality of primary windings each inductively coupled to a different one of the cores, and a helical secondary winding which is disposed coaxially of the cores and passes therethrough in circumferential succession. Additional novelty resides in the disposition of the electron source cathode filament input leads interiorly of the transformer secondary winding which is hollow, as well as in the employment of a half-wave filament supply which is synchronously operated with the transformer supply such that the transformer is pulsed during the zero current portions of the half-wave cycle.

  16. ОЦЕНКА СЕЗОННОГО РАСПРЕДЕЛЕНИЯ БЕЛУХИ DELPHINAPTERUS LEUCAS И ОБЪЕКТОВ ЕЕ ПИТАНИЯ В ПРИБРЕЖНЫХ ВОДАХ СЕВЕРО-ЗАПАДНОЙ ЧАСТИ БЕРИНГОВА МОРЯ

    OpenAIRE

    Литовка, Д.; Андронов, П.; Батанов, Р.

    2013-01-01

    Впервые с помощью слежения за мечеными белухами со спутников была подтверждена описанная ранее схема осенних миграций и зимнего распределения анадырской белухи, построенная на основе многолетних наблюдений, опросных сведений и авиаучетов в разные годы. Была выявлена акватория зимнего нагула анадырской белухи и белух из других популяций из Канады и Аляски (от мыса Наварин до острова Св. Лаврентия). Анализ погружений выявил в основном возрастные отличия в поведении белух, а также отличия в погр...

  17. Basic electronics

    CERN Document Server

    Tayal, DC

    2010-01-01

    The second edition of this book incorporates the comments and suggestions of my friends and students who have critically studied the first edition. In this edition the changes and additions have been made and subject matter has been rearranged at some places. The purpose of this text is to provide a comprehensive and up-to-date study of the principles of operation of solid state devices, their basic circuits and application of these circuits to various electronic systems, so that it can serve as a standard text not only for universities and colleges but also for technical institutes. This book

  18. Electronic materials

    CERN Document Server

    Kwok, H L

    2010-01-01

    The electronic properties of solids have become of increasing importance in the age of information technology. The study of solids and materials, while having originated from the disciplines of physics and chemistry, has evolved independently over the past few decades. The classical treatment of solid-state physics, which emphasized classifications, theories and fundamental physical principles, is no longer able to bridge the gap between materials advances and applications. In particular, the more recent developments in device physics and technology have not necessarily been driven by new conc

  19. Electronic Router

    Science.gov (United States)

    Crusan, Jason

    2005-01-01

    Electronic Router (E-Router) is an application program for routing documents among the cognizant individuals in a government agency or other organization. E-Router supplants a prior 14 NASA Tech Briefs, May 2005 system in which paper documents were routed physically in packages by use of paper slips, packages could be lost, routing times were unacceptably long, tracking of packages was difficult, and there was a need for much photocopying. E-Router enables a user to create a digital package to be routed. Input accepted by E-Router includes the title of the package, the person(s) to whom the package is to be routed, attached files, and comments to reviewers. Electronic mail is used to notify reviewers of needed actions. The creator of the package can, at any time, see the status of the package in the routing structure. At the end of the routing process, E-Router keeps a record of the package and of approvals and/or concurrences of the reviewers. There are commercial programs that perform the general functions of E-Router, but they are more complicated. E-Router is Web-based, easy to use, and does not require the installation or use of client software.

  20. 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

  1. Electronic Preprints

    Science.gov (United States)

    Hanisch, R.

    1999-12-01

    Despite the tremendous advances in electronic publications and the increasing rapidity with which papers are now moving from acceptance into ``print,'' preprints continue to be an important mode of communication within the astronomy community. The Los Alamos e-preprint service, astro-ph, provides for rapid and cost-free (to authors and readers) dissemination of manuscripts. As the use of astro-ph has increased the number of paper preprints in circulation to libraries has decreased, and institutional preprint series appear to be waning. It is unfortunate, however, that astro-ph does not function in collaboration with the refereed publications. For example, there is no systematic tracking of manuscripts from preprint to their final, published form, and as a centralized archive it is difficult to distribute the tracking and maintenance functions. It retains documents that have been superseded or have become obsolete. We are currently developing a distributed preprint and document management system which can support both distributed collections of preprints (e.g., traditional institutional preprint series), can link to the LANL collections, can index other documents in the ``grey'' literature (observatory reports, telescope and instrument user's manuals, calls for proposals, etc.), and can function as a manuscript submission tool for the refereed journals. This system is being developed to work cooperatively with the refereed literature so that, for example, links to preprints are updated to links to the final published papers.

  2. Sustainable Management of Electronics

    Science.gov (United States)

    To provide information on EPAs strategy for electronics stewardship, certified electronics recyclers and the Challenge; as well as where to donate unwanted electronics, how to calculate benefits, and what's going on with electronics mgmt in their states.

  3. EDITORIAL: Synaptic electronics Synaptic electronics

    Science.gov (United States)

    Demming, Anna; Gimzewski, James K.; Vuillaume, Dominique

    2013-09-01

    Conventional computers excel in logic and accurate scientific calculations but make hard work of open ended problems that human brains handle easily. Even von Neumann—the mathematician and polymath who first developed the programming architecture that forms the basis of today's computers—was already looking to the brain for future developments before his death in 1957 [1]. Neuromorphic computing uses approaches that better mimic the working of the human brain. Recent developments in nanotechnology are now providing structures with very accommodating properties for neuromorphic approaches. This special issue, with guest editors James K Gimzewski and Dominique Vuillaume, is devoted to research at the serendipitous interface between the two disciplines. 'Synaptic electronics', looks at artificial devices with connections that demonstrate behaviour similar to synapses in the nervous system allowing a new and more powerful approach to computing. Synapses and connecting neurons respond differently to incident signals depending on the history of signals previously experienced, ultimately leading to short term and long term memory behaviour. The basic characteristics of a synapse can be replicated with around ten simple transistors. However with the human brain having around 1011 neurons and 1015 synapses, artificial neurons and synapses from basic transistors are unlikely to accommodate the scalability required. The discovery of nanoscale elements that function as 'memristors' has provided a key tool for the implementation of synaptic connections [2]. Leon Chua first developed the concept of the 'The memristor—the missing circuit element' in 1971 [3]. In this special issue he presents a tutorial describing how memristor research has fed into our understanding of synaptic behaviour and how they can be applied in information processing [4]. He also describes, 'The new principle of local activity, which uncovers a minuscule life-enabling "Goldilocks zone", dubbed the

  4. Electronic Mimosa

    Science.gov (United States)

    Gupta, Sanjay; Datta, Meera S.; Rana, Vivek; Grover, Shailesh

    1996-04-01

    This paper describes the design of a low-cost, 2D, electromagnetic tracking device for personal computers. This interface makes use of the well-known principle of electromagnetic induction to locate the position of a transmitter in an x-y plane. This device has a ring which is worn by the user on the index finger. The computer monitor is overlaid with a transparent screen equipped with tuned electromagnetic sensors. These sensors pick up the signals transmitted by the transmitter coil on the finger. The receiver circuit extracts the envelope of the received signal and digitizes it. These digitized values of x and y axis signals are read by the computer through the standard parallel port. The system software running on the computer calculates the x and y co-ordinates of the transmitter coil and displays a cursor at that location. The transmitter also has a button which can be used like a mouse button. This keypress information is also transmitted by the electromagnetic means. The device driver for this tracker replaces the standard mouse driver. Hence most applications which use a mouse can also use this tracker. Its name `Mimosa' indicates that the user need not touch the screen (Mimosa Pudica is the Latin name of a plant whose leaves wilt when touched). Presently work is on to achieve uniform sensitivity over the entire screen and reducing transmitter power consumption. In order to demonstrate its working, a small, 3D game was written. The player has to reach a pre-defined location after traversing through a maze. The paper describes the interface electronics, system software, mechanical design and the sample application.

  5. 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.

  6. Nano-Electronics and Bio-Electronics

    Science.gov (United States)

    Srivastava, Deepak; Kwak, Dochan (Technical Monitor)

    2001-01-01

    Viewgraph presentation on Nano-Electronics and Bio-Electronics is discussed. Topics discussed include: NASA Ames nanotechnology program, Potential Carbon Nanotube (CNT) application, CNT synthesis,Computational Nanotechnology, and protein nanotubes.

  7. Electronics for LHC Experiments

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    This document gathers the abstracts of most presentations made at this workshop on electronics for the large hadron collider (LHC) experiments. The presentations were arranged into 6 sessions: 1) electronics for tracker, 2) trigger electronics, 3) detector control systems, 4) data acquisition, 5) electronics for calorimeters and electronics for muons, and 6) links, power systems, grounding and shielding, testing and quality assurance.

  8. Interface Electronic Circuitry for an Electronic Tongue

    Science.gov (United States)

    Keymeulen, Didier; Buehler, Martin

    2007-01-01

    Electronic circuitry has been developed to serve as an interface between an electronic tongue and digital input/output boards in a laptop computer that is used to control the tongue and process its readings. Electronic tongues can be used for a variety of purposes, including evaluating water quality, analyzing biochemicals, analyzing biofilms, and measuring electrical conductivities of soils.

  9. Electron beam focusing system

    Energy Technology Data Exchange (ETDEWEB)

    Dikansky, N.; Nagaitsev, S.; Parkhomchuk, V.

    1997-09-01

    The high energy electron cooling requires a very cold electron beam. Thus, the electron beam focusing system is very important for the performance of electron cooling. A system with and without longitudinal magnetic field is presented for discussion. Interaction of electron beam with the vacuum chamber as well as with the background ions and stored antiprotons can cause the coherent electron beam instabilities. Focusing system requirements needed to suppress these instabilities are presented.

  10. 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.

  11. Electronic Correlations in Electron Transfer Systems

    Science.gov (United States)

    Bulla, Ralf; Tornow, Sabine; Anders, Frithjof

    Electron transfer processes play a central role in many chemical and biological systems. Already the transfer of a single electron from the donor to the acceptor can be viewed as a complicated many-body problem, due to the coupling of the electron to the infinitely many environmental degrees of freedom, realized by density fluctuations of the solvent or molecular vibrations of the protein matrix. We focus on the quantum mechanical modelling of two-electron transfer processes whose dynamics is governed by the Coulomb interaction between the electrons as well as the environmental degrees of freedoms represented by a bosonic bath. We identify the regime of parameters in which concerted transfer of the two electrons occurs and discuss the influence of the Coulomb repulsion and the coupling strength to the environment on the electron transfer rate. Calculations are performed using the non-perturbative numerical renormalization group approach for both equilibrium and non-equilibrium properties.

  12. Electron Microscopy Center (EMC)

    Data.gov (United States)

    Federal Laboratory Consortium — The Electron Microscopy Center (EMC) at Argonne National Laboratory develops and maintains unique capabilities for electron beam characterization and applies those...

  13. Investigations on Electronic Materials

    OpenAIRE

    E. Pugnor; T. Kormány

    1982-01-01

    Electronics has been described as a materials oriented technology. In this sense a short review is given concerning: the connection of materials characterization to the design and processing of electronic components; the most important materials characterization methods used for electronic materials; the strategy of organizing a complete material characterization system for selected electronic components.

  14. Electron-attachment processes

    Science.gov (United States)

    Christophorou, L. G.; McCorkle, D. L.; Christodoulides, A. A.

    Topics covered include: modes of production of negative ions, techniques for the study of electron attachment processes, dissociative electron attachment to ground state molecules, dissociative electron attachment to hot molecules (effects of temperature on dissociative electron attachment), molecular parent negative ions, and negative ions formed by ion pair processes and by collisions of molecules with ground state and Rydberg atoms.

  15. Electronic Health Records

    Science.gov (United States)

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Electronic Health Records KidsHealth > For Teens > Electronic Health Records Print A A A What's in ... t happen overnight, they are coming. Understanding EHRs Electronic health records (EHR) — also called electronic medical records ( ...

  16. Introduction to electronics

    CERN Document Server

    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...

  17. Introduction to Electronics course

    CERN Document Server

    CERN. Geneva HR-RFA

    2006-01-01

    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...

  18. Electronic Health Records

    Science.gov (United States)

    ... Loss Surgery? A Week of Healthy Breakfasts Shyness Electronic Health Records KidsHealth > For Teens > Electronic Health Records A A A What's in this ... t happen overnight, they are coming. Understanding EHRs Electronic health records (EHR) — also called electronic medical records ( ...

  19. Introduction to Electronic Marketing.

    Science.gov (United States)

    Dilbeck, Lettie

    These materials for a five-unit course were developed to introduce secondary and postsecondary students to the use of electronic equipment in marketing. The units cover the following topics: electronic marketing as a valid marketing approach; telemarketing; radio electronic media marketing; television electronic media marketing; and cable TV…

  20. Hybrid printed electronics

    NARCIS (Netherlands)

    Koetse, M.; Smits, E.; Rubingh, E.; Teunissen, P.; Kusters, R.; Abbel, R.; Brand, J. van den

    2016-01-01

    Although many electronic functionalities can be realized by printed or organic electronics, short-term marketable products often require robust, reproducible, and nondisturbing technologies. In this chapter we show how hybrid electronics, a combination of printed circuitry, thin-film electronics,

  1. 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

  2. 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.

  3. Practical microwave electron devices

    CERN Document Server

    Meurant, Gerard

    2013-01-01

    Practical Microwave Electron Devices provides an understanding of microwave electron devices and their applications. All areas of microwave electron devices are covered. These include microwave solid-state devices, including popular microwave transistors and both passive and active diodes; quantum electron devices; thermionic devices (including relativistic thermionic devices); and ferrimagnetic electron devices. The design of each of these devices is discussed as well as their applications, including oscillation, amplification, switching, modulation, demodulation, and parametric interactions.

  4. Electronics engineer's reference book

    CERN Document Server

    Turner, L W

    1976-01-01

    Electronics Engineer's Reference Book, 4th Edition is a reference book for electronic engineers that reviews the knowledge and techniques in electronics engineering and covers topics ranging from basics to materials and components, devices, circuits, measurements, and applications. This edition is comprised of 27 chapters; the first of which presents general information on electronics engineering, including terminology, mathematical equations, mathematical signs and symbols, and Greek alphabet and symbols. Attention then turns to the history of electronics; electromagnetic and nuclear radiatio

  5. Single electron-ics with carbon nanotubes

    NARCIS (Netherlands)

    Götz, G.T.J.

    2010-01-01

    We experimentally investigate Quantum Dots, formed in Carbon Nanotubes. The first part of this thesis deals with charge sensing on such quantum dots. The charge sensor is a metallic Single-electron-transistor, sensitive to the charge of a single electron on the quantum dot. We use this technique for

  6. 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.

  7. 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.

  8. Electron transporting semiconducting polymers in organic electronics.

    Science.gov (United States)

    Zhao, Xingang; Zhan, Xiaowei

    2011-07-01

    Significant progress has been achieved in the preparation of semiconducting polymers over the past two decades, and successful commercial devices based on them are slowly beginning to enter the market. However, most of the conjugated polymers are hole transporting, or p-type, semiconductors that have seen a dramatic rise in performance over the last decade. Much less attention has been devoted to electron transporting, or n-type, materials that have lagged behind their p-type counterparts. Organic electron transporting materials are essential for the fabrication of organic p-n junctions, organic photovoltaic cells (OPVs), n-channel organic field-effect transistors (OFETs), organic light-emitting diodes (OLEDs) and complementary logic circuits. In this critical review we focus upon recent developments in several classes of electron transporting semiconducting polymers used in OLEDs, OFETs and OPVs, and survey and analyze what is currently known concerning electron transporting semiconductor architecture, electronic structure, and device performance relationships (87 references).

  9. Polycyclic aromatic hydrocarbon-DNA adducts in beluga whales from the Arctic.

    Science.gov (United States)

    Mathieu, A; Payne, J F; Fancey, L L; Santella, R M; Young, T L

    1997-05-01

    The Arctic is still relatively pristine in nature, but it is also vulnerable to pollution because contaminants originating from midlatitudes are transported to the Arctic by atmospheric processes, ocean currents, and rivers (Muir et al., 1992). Recognition of this fact of Arctic vulnerability has resulted in a Declaration on the Protection of the Arctic Environment by eight Arctic countries. A manifest aim of this declaration is to develop an Arctic Monitoring and Assessment Program. We report here on the presence of measurable levels of polycyclic aromatic hydrocarbon-DNA adducts, including relatively high levels in Arctic beluga (Delphinapterus leucas). These results lend support to the value of developing biological assessment programs for Arctic wildlife.

  10. Measuring Hearing in Wild Beluga Whales.

    Science.gov (United States)

    Mooney, T Aran; Castellote, Manuel; Quakenbush, Lori; Hobbs, Roderick; Goertz, Caroline; Gaglione, Eric

    2016-01-01

    We measured the hearing abilities of seven wild beluga whales (Delphinapterus leucas) during a collection-and-release experiment in Bristol Bay, AK. Here we summarize the methods and initial data from one animal and discuss the implications of this experiment. Audiograms were collected from 4 to 150 kHz. The animal with the lowest threshold heard best at 80 kHz and demonstrated overall good hearing from 22 to 110 kHz. The robustness of the methodology and data suggest that the auditory evoked potential audiograms can be incorporated into future collection-and-release health assessments. Such methods may provide high-quality results for multiple animals, facilitating population-level audiograms and hearing measures in new species.

  11. Induction of micronuclei in vitro by organochlorine compounds in beluga whale skin fibroblasts.

    Science.gov (United States)

    Gauthier, J M; Dubeau, H; Rassart, E

    1999-02-02

    Beluga whales (Delphinapterus leucas) inhabiting the St. Lawrence estuary are highly contaminated with environmental pollutants and have a high incidence of cancer. Environmental contaminants may be partly responsible for the high cancer incidence observed in this population. DNA damage plays an important role in the development of cancer. The micronuclei (MN) assay was used to test the genotoxic potential of organochlorine (OC) pesticides with and without external metabolic factor in skin fibroblasts of an Arctic beluga whale. Toxaphene, chlordane and p,p'-DDT induced significant (pSt. Lawrence beluga whales. However, because of the known genotoxicity of toxaphene and the long lifespan of beluga whales, it cannot be excluded that toxaphene may pose a long-term genetic hazard to the more contaminated whales of this population.

  12. Giardiasis in pinnipeds from eastern Canada.

    Science.gov (United States)

    Measures, L N; Olson, M

    1999-10-01

    Cysts of Giardia sp. were detected in feces from the rectum of 20 of 74 pinnipeds examined from the eastern coast of Canada in 1997 and 1998 using a monoclonal antibody technique. Infected pinnipeds included 15 adult harp seals (Phoca groenlandica), four adult grey seals (Halichoerus grypus), and one juvenile harbor seal (Phoca vitulina). Cysts were not detected in 15 seal pups St. Lawrence. The overall prevalence of Giardia sp. in grey and harbor seals, excluding pups, from the Gulf and St. Lawrence estuary was 23%. Feces from 11 beluga (Delphinapterus leucas) and one northern bottle-nosed whale (Hyperoodon ampullatus) stranded in the St. Lawrence estuary were negative for Giardia sp. cysts. The significance of Giardia sp. in marine mammals, shown here for the first time in eastern coastal Canada, is unknown.

  13. Bone fluoride concentrations in beluga whales from Canada.

    Science.gov (United States)

    Mikaelian, I; Qualls, C W; De Guise, S; Whaley, M W; Martineau, D

    1999-04-01

    Beluga whales (Delphinapterus leucas) from the St. Lawrence Estuary have been reported to have dental and bone abnormalities. To determine whether these lesions could be caused by high exposure to fluorides, we measured bone fluoride levels in eight beluga whales stranded on the shores of the St. Lawrence Estuary (Quebec, Canada), and in nine beluga whales killed by Inuit hunters in the Hudson Bay (North Western Territories, Canada). In both groups, fluoride concentrations were higher than those found in terrestrial mammals intoxicated by fluorides. Unexpectedly, fluoride concentration was significantly higher in beluga whales from the Hudson Bay (mean +/- SD: 10.365 +/- 1.098 ppm) than in beluga whales from the St. Lawrence Estuary (4.539 +/- 875 ppm) and was positively correlated with age in the latter population. Differences in diet might explain the differences in fluoride concentrations found between these two populations.

  14. Aerial Surveys of Endangered Whales in the Northern Bering, Eastern Chukchi, and Alaskan Beaufort Seas, 1985: With a Seven Year Review, 1979-85.

    Science.gov (United States)

    1986-08-01

    8217 . " - • " " " ’ " ’"" . - - - " "" "° " " "" " " , , - " UUSS USSRA as LEGENDJ 0GV S CAPE PRINCE OF WALES % .4(DO crnM BERING SEA OCG 00 M 0a hI)rO 0 0 0 1 Kp 000...o,,o_.._ .- Demarcation Pt Cape Lisbuneo 680I , ialn 680: 660 USSR16 100 15 1 apatocni Prince of Wales AndSK i nest coe s dNo o i 64...and migration patterns of the white whale ( Beluga ), Delphinapterus leucas. Rep. int. Whal. Commn. vol. 30:465-480. 1980. Herzing, D.L. and B.R. Mate

  15. 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

  16. High energy electron cooling

    Energy Technology Data Exchange (ETDEWEB)

    Parkhomchuk, V. [Budker Institute of Nuclear Physics, Novosibirsk (Russian Federation)

    1997-09-01

    High energy electron cooling requires a very cold electron beam. The questions of using electron cooling with and without a magnetic field are presented for discussion at this workshop. The electron cooling method was suggested by G. Budker in the middle sixties. The original idea of the electron cooling was published in 1966. The design activities for the NAP-M project was started in November 1971 and the first run using a proton beam occurred in September 1973. The first experiment with both electron and proton beams was started in May 1974. In this experiment good result was achieved very close to theoretical prediction for a usual two component plasma heat exchange.

  17. RHIC electron lenses upgrades

    Energy Technology Data Exchange (ETDEWEB)

    Gu, X. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Altinbas, Z. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Bruno, D. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Binello, S. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Costanzo, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Drees, A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Fischer, W. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Gassner, D. M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Hock, J. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Hock, K. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Harvey, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Luo, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Marusic, A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Mi, C. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Mernick, K. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Minty, M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Michnoff, R. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Miller, T. A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Pikin, A. I. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Robert-Demolaize, G. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Samms, T. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Shrey, T. C. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Schoefer, V. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Tan, Y. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Than, R. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; Thieberger, P. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.; White, S. M. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2015-05-03

    In the Relativistic Heavy Ion Collider (RHIC) 100 GeV polarized proton run in 2015, two electron lenses were used to partially compensate for the head-on beam-beam effect for the first time. Here, we describe the design of the current electron lens, detailing the hardware modifications made after the 2014 commissioning run with heavy ions. A new electron gun with 15-mm diameter cathode is characterized. The electron beam transverse profile was measured using a YAG screen and fitted with a Gaussian distribution. During operation, the overlap of the electron and proton beams was achieved using the electron backscattering detector in conjunction with an automated orbit control program.

  18. Electronic Commerce and Competitive Procurement

    Science.gov (United States)

    1991-06-01

    Explains the application of electronic commerce techniques (electronic data interchange (EDI), electronic mail (E-mail), electronic bulletin boards...purchase procedures of the Federal Acquisition Regulation (FAR). Changes to the FAR to recognize electronic commerce are recommended. Also discussed...are opportunities to use electronic commerce and small business and legal considerations of electronic commerce . This report describes how electronic

  19. Certified Electronics Recyclers

    Science.gov (United States)

    Learn how EPA encourages all electronics recyclers become certified by demonstrating to an accredited, independent third-party auditor and that they meet specific standards to safely recycle and manage electronics.

  20. Chapter 9: Electronics

    OpenAIRE

    Spieler, Helmuth G

    2008-01-01

    Sophisticated front-end electronics are a key part of practically all modern radiation detector systems. This chapter introduces the basic principles and their implementation. Topics include signal acquisition, electronic noise, pulse shaping (analog and digital), and data readout techniques.

  1. Chapter 9: Electronics

    Energy Technology Data Exchange (ETDEWEB)

    Grupen, Claus; Shwartz, Boris A.

    2006-12-19

    Sophisticated front-end electronics are a key part of practically all modern radiation detector systems. This chapter introduces the basic principles and their implementation. Topics include signal acquisition, electronic noise, pulse shaping (analog and digital), and data readout techniques.

  2. Presidential Electronic Records Library

    Data.gov (United States)

    National Archives and Records Administration — PERL (Presidential Electronic Records Library) used to ingest and provide internal access to the Presidential electronic Records of the Reagan, Bush, and Clinton...

  3. THE ELECTRONIC SIGNATURE

    Directory of Open Access Journals (Sweden)

    Voiculescu Madalina Irena

    2009-05-01

    Full Text Available Article refers to significance and the digital signature in electronic commerce. Internet and electronic commerce open up many new opportunities for the consumer, yet, the security (or perceived lack of security of exchanging personal and financial data

  4. Electronic Submission of Labels

    Science.gov (United States)

    Pesticide registrants can provide draft and final labels to EPA electronically for our review as part of the pesticide registration process. The electronic submission of labels by registrants is voluntary but strongly encouraged.

  5. Chapter 9: Electronics

    Energy Technology Data Exchange (ETDEWEB)

    Grupen, Claus; Shwartz, Boris A.

    2006-12-19

    Sophisticated front-end electronics are a key part of practically all modern radiation detector systems. This chapter introduces the basic principles and their implementation. Topics include signal acquisition, electronic noise, pulse shaping (analog and digital), and data readout techniques.

  6. Laboratory Handbook Electronics

    CERN Multimedia

    1966-01-01

    Laboratory manual 1966 format A3 with the list of equipment cables, electronic tubes, chassis, diodes transistors etc. One of CERN's first material catalogue for construction components for mechanical and electronic chassis.

  7. 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.

  8. Electronics materials research

    Science.gov (United States)

    1982-01-01

    The electronic materials and is aimed at the establishment of quantitative relationships underlying crystal growth parameters, materials properties, electronic characteristics and device applications. The overall program evolves about the following main thrust areas: (1) crystal growth novel approaches to engineering of semiconductor materials; (2) investigation of materials properties and electronic characteristics on a macro and microscale; (3) surface properties and surface interactions with the bulk and ambients; (4) electronic properties controlling device applications and device performance.

  9. Thermography of electronic devices

    OpenAIRE

    Panfilova S. P.; Vlasov A. I.; Gridnev V. N.; Chervinsky A. S.

    2007-01-01

    The possibility of application of thermography to diagnose the electronic devices is analyzed in the article. Typical faults of electronic devices which can be found by means of thermography are given. Advantages of noncontact thermal inspection in comparison with the contact one are described. Some features of thermography of electronic devices are considered. Thermography apparatus is viewed and some pieces of advice about choosing it for electronic devices diagnosis are given. An example o...

  10. Electronics and computer acronyms

    CERN Document Server

    Brown, Phil

    1988-01-01

    Electronics and Computer Acronyms presents a list of almost 2,500 acronyms related to electronics and computers. The material for this book is drawn from a number of subject areas, including electrical, electronics, computers, telecommunications, fiber optics, microcomputers/microprocessors, audio, video, and information technology. The acronyms also encompass avionics, military, data processing, instrumentation, units, measurement, standards, services, organizations, associations, and companies. This dictionary offers a comprehensive and broad view of electronics and all that is associated wi

  11. Extreme environment electronics

    CERN Document Server

    Cressler, John D

    2012-01-01

    Unfriendly to conventional electronic devices, circuits, and systems, extreme environments represent a serious challenge to designers and mission architects. The first truly comprehensive guide to this specialized field, Extreme Environment Electronics explains the essential aspects of designing and using devices, circuits, and electronic systems intended to operate in extreme environments, including across wide temperature ranges and in radiation-intense scenarios such as space. The Definitive Guide to Extreme Environment Electronics Featuring contributions by some of the world's foremost exp

  12. Mechanical Engineering for Electronics.

    OpenAIRE

    Was, Loïc

    2012-01-01

    Schlumberger drilling tools are exposed to very hard loading conditions (shocks, vibrations, thermal cycling) while performing a job. As these tools are full of electronics, issues can quickly come from electronics failure. Mechanisms of failure occurring in electronics are very complex but can be predicted in some cases. The first part of the thesis describes in which context mechanical engineering applied to electronics is used in Schlumberger. The different kinds of failure which will be i...

  13. Handbook on electronic commerce

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, M. [Illinois Univ., Urbana, IL (United States). Beckman Inst. for Advanced Science and Technology; Blanning, R. [Vanderbilt Univ., Nashville, TN (United States). Owen Graduate School of Management; Strader, T. [Iowa State Univ., Ames, IA (United States). Management Information Systems; Whinston, A. [eds.] [Texas Univ., Austin, TX (United States). Dept. of Management Science and Information Systems

    2000-07-01

    The world is undergoing a revolution to a digital economy, with pronounced implications for corporate strategy, marketing, operations, information systems, customer services, global supply-chain management, and product distribution. This handbook examines the aspects of electronic commerce, including electronic storefront, on-line business, consumer interface, business-to-business networking, digital payment, legal issues, information product development, and electronic business models. Indispensable for academics, students and professionals who are interested in Electronic Commerce and Internet Business. (orig.)

  14. Atomicity in Electronic Commerce,

    Science.gov (United States)

    1996-01-01

    tremendous demand for the ability to electronically buy and sell goods over networks. Electronic commerce has inspired a large variety of work... commerce . It then briefly surveys some major types of electronic commerce pointing out flaws in atomicity. We pay special attention to the atomicity...problems of proposals for digital cash. The paper presents two examples of highly atomic electronic commerce systems: NetBill and Cryptographic Postage Indicia.

  15. 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.

  16. Technology of Electronic Signatur

    OpenAIRE

    2004-01-01

    An electronic signature uses a hash of message and an asymetrical algorithm of encryption for its generation. During verification of message on receiver side the hash of original message must be identical with the hash of received message. Electronic message is secured autentization of author and integrity of transmission date. By electronic signature it is possible to sign everything what is in digital form.

  17. ELECTRONS IN NONPOLAR LIQUIDS.

    Energy Technology Data Exchange (ETDEWEB)

    HOLROYD,R.A.

    2002-10-22

    Excess electrons can be introduced into liquids by absorption of high energy radiation, by photoionization, or by photoinjection from metal surfaces. The electron's chemical and physical properties can then be measured, but this requires that the electrons remain free. That is, the liquid must be sufficiently free of electron attaching impurities for these studies. The drift mobility as well as other transport properties of the electron are discussed here as well as electron reactions, free-ion yields and energy levels, Ionization processes typically produce electrons with excess kinetic energy. In liquids during thermalization, where this excess energy is lost to bath molecules, the electrons travel some distance from their geminate positive ions. In general the electrons at this point are still within the coulombic field of their geminate ions and a large fraction of the electrons recombine. However, some electrons escape recombination and the yield that escapes to become free electrons and ions is termed G{sub fi}. Reported values of G{sub fi} for molecular liquids range from 0.05 to 1.1 per 100 eV of energy absorbed. The reasons for this 20-fold range of yields are discussed here.

  18. 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

  19. Arduino electronics blueprints

    CERN Document Server

    Wilcher, Don

    2015-01-01

    This book is intended for those who want to learn about electronics and coding by building amazing devices and gadgets with Arduino. If you are an experienced developer who understands the basics of electronics, then you can quickly learn how to build smart devices using Arduino. The only experience needed is a desire to learn about electronics, circuit breadboarding, and coding.

  20. Electron measurement in PHENIX

    Energy Technology Data Exchange (ETDEWEB)

    Akiba, Y. [Univ. of Tokyo, Tanashi (Japan)

    1995-07-15

    Electron Measurement in PHENIX detector at RHIC is discussed. The yield and S/N ratio at vector meson peaks ({phi}, {omega}, {rho}{sup o}, and J/{psi}) are evaluated. The electrons from open charm decay, and its consequence to the di-electron measurements is discussed.

  1. EFFECTIVE ELECTRONIC TUTORIAL

    Directory of Open Access Journals (Sweden)

    Andrei A. Fedoseev

    2014-01-01

    Full Text Available The article analyzes effective electronic tutorials creation and application based on the theory of pedagogy. Herewith the issues of necessary electronic tutorial functional, ways of the educational process organization with the use of information and communication technologies and the logistics of electronic educational resources are touched upon. 

  2. Polarized Electron Source Developments

    Energy Technology Data Exchange (ETDEWEB)

    Charles K. Sinclair

    1990-02-23

    Presently, only two methods of producing beams of polarized electrons for injection into linear accelerators are in use. Each of these methods uses optical pumping by circularly polarized light to produce electron polarization. In one case, electron polarization is established in metastable helium atoms, while in the other case, the polarized electrons are produced in the conduction band of appropriate semiconductors. The polarized electrons are liberated from the helium metastable by chemi-ionization, and from the semiconductors by lowering the work function at the surface of the material. Developments with each of these sources since the 1988 Spin Physics Conference are reviewed, and the prospects for further improvements discussed.

  3. Soldering in electronics assembly

    CERN Document Server

    Judd, Mike

    2013-01-01

    Soldering in Electronics Assembly discusses several concerns in soldering of electronic assemblies. The book is comprised of nine chapters that tackle different areas in electronic assembly soldering. Chapter 1 discusses the soldering process itself, while Chapter 2 covers the electronic assemblies. Chapter 3 talks about solders and Chapter 4 deals with flux. The text also tackles the CS and SC soldering process. The cleaning of soldered assemblies, solder quality, and standards and specifications are also discussed. The book will be of great use to professionals who deal with electronic assem

  4. Ultracold Ordered Electron Beam

    Science.gov (United States)

    Habs, D.; Kramp, J.; Krause, P.; Matl, K.; Neumann, R.; Schwalm, D.

    1988-01-01

    We have started an experimental program to develop an ultracold electron beam, which can be used together with a standard electron cooling device in the Heidelberg Test Storage Ring TSR. In contrast to the standard-type design using electron beam extraction from a heated cathode, the ultracold beam is produced by photoemission of electrons from a cooled semiconductor crystal irradiated with an intense near-infrared laser light beam. Adiabatic acceleration is expected to provide ordering of the electron beam itself. Besides the cooling of ion beams to extremely low temperatures, with the aim of obtaining crystallization, the ultracold beam will constitute an excellent target for atomic physics experiments.

  5. Ultracold ordered electron beam

    Energy Technology Data Exchange (ETDEWEB)

    Habs, D.; Kramp, J.; Krause, P.; Matl, K.; Neumann, R.; Schwalm, D.

    1988-01-01

    We have started an experimental program to develop an ultracold electron beam, which can be used together with a standard electron cooling device in the Heidelberg Test Storage Ring TSR. In contrast to the standard-type design using electron beam extraction beam extraction from a heated cathode, the ultracold beam is produced by photoemission of electrons from a cooled semiconductor crystal irradiated with an intense near-infrared laser light beam. Adiabatic acceleration is expected to provide ordering of the electron beam itself. Besides the cooling of ion beams to extremely low temperatures, with the aim of obtaining crystallization, the ultracold beam will constitute an excellent target for atomic physics experiments.

  6. Electronic equipment packaging technology

    CERN Document Server

    Ginsberg, Gerald L

    1992-01-01

    The last twenty years have seen major advances in the electronics industry. Perhaps the most significant aspect of these advances has been the significant role that electronic equipment plays in almost all product markets. Even though electronic equipment is used in a broad base of applications, many future applications have yet to be conceived. This versatility of electron­ ics has been brought about primarily by the significant advances that have been made in integrated circuit technology. The electronic product user is rarely aware of the integrated circuits within the equipment. However, the user is often very aware of the size, weight, mod­ ularity, maintainability, aesthetics, and human interface features of the product. In fact, these are aspects of the products that often are instrumental in deter­ mining its success or failure in the marketplace. Optimizing these and other product features is the primary role of Electronic Equipment Packaging Technology. As the electronics industry continues to pr...

  7. Advanced adhesives in electronics

    CERN Document Server

    Bailey, C

    2011-01-01

    Adhesives are widely used in the manufacture of electronic devices to act as passive and active components. Recently there has been considerable interest in the use of conductive adhesives. This book reviews key types of conductive adhesives, processing methods, properties and the way they can be modelled as well as potential applications.$bAdhesives for electronic applications serve important functional and structural purposes in electronic components and packaging, and have developed significantly over the last few decades. Advanced adhesives in electronics reviews recent developments in adhesive joining technology, processing and properties. The book opens with an introduction to adhesive joining technology for electronics. Part one goes on to cover different types of adhesive used in electronic systems, including thermally conductive adhesives, isotropic and anisotropic conductive adhesives and underfill adhesives for flip-chip applications. Part two focuses on the properties and processing of electronic ...

  8. Electron crystallography and aquaporins.

    Science.gov (United States)

    Schenk, Andreas D; Hite, Richard K; Engel, Andreas; Fujiyoshi, Yoshinori; Walz, Thomas

    2010-01-01

    Electron crystallography of two-dimensional (2D) crystals can provide information on the structure of membrane proteins at near-atomic resolution. Originally developed and used to determine the structure of bacteriorhodopsin (bR), electron crystallography has recently been applied to elucidate the structure of aquaporins (AQPs), a family of membrane proteins that form pores mostly for water but also other solutes. While electron crystallography has made major contributions to our understanding of the structure and function of AQPs, structural studies on AQPs, in turn, have fostered a number of technical developments in electron crystallography. In this contribution, we summarize the insights electron crystallography has provided into the biology of AQPs, and describe technical advancements in electron crystallography that were driven by structural studies on AQP 2D crystals. In addition, we discuss some of the lessons that were learned from electron crystallographic work on AQPs.

  9. Automotive electronics design fundamentals

    CERN Document Server

    Zaman, Najamuz

    2015-01-01

    This book explains the topology behind automotive electronics architectures and examines how they can be profoundly augmented with embedded controllers. These controllers serve as the core building blocks of today’s vehicle electronics. Rather than simply teaching electrical basics, this unique resource focuses on the fundamental concepts of vehicle electronics architecture, and details the wide variety of Electronic Control Modules (ECMs) that enable the increasingly sophisticated "bells & whistles" of modern designs.  A must-have for automotive design engineers, technicians working in automotive electronics repair centers and students taking automotive electronics courses, this guide bridges the gap between academic instruction and industry practice with clear, concise advice on how to design and optimize automotive electronics with embedded controllers.

  10. Medan Electronic Mall Arsitektur Ikonik

    OpenAIRE

    David,, A.

    2014-01-01

    With present the Medan Electronic Mall is intended to meet the needs of electronic goods from electronic of communication, Office Electronics, Household Electronics, Hobbies or electronic game, Medan Electronic Mall also hosts for the people of North Sumatra Province especially for people of Medan City to get particular information will be the development of electronic goods and also enjoy all kinds of things related to electronics such as Game Center, Cyber/Virtual Game, Internet...

  11. Engineered phages for electronics.

    Science.gov (United States)

    Cui, Yue

    2016-11-15

    Phages are traditionally widely studied in biology and chemistry. In recent years, engineered phages have attracted significant attentions for functionalization or construction of electronic devices, due to their specific binding, catalytic, nucleating or electronic properties. To apply the engineered phages in electronics, these are a number of interesting questions: how to engineer phages for electronics? How are the engineered phages characterized? How to assemble materials with engineered phages? How are the engineered phages micro or nanopatterned? What are the strategies to construct electronics devices with engineered phages? This review will highlight the early attempts to address these questions and explore the fundamental and practical aspects of engineered phages in electronics, including the approaches for selection or expression of specific peptides on phage coat proteins, characterization of engineered phages in electronics, assembly of electronic materials, patterning of engineered phages, and construction of electronic devices. It provides the methodologies and opens up ex-cit-ing op-por-tu-ni-ties for the development of a variety of new electronic materials and devices based on engineered phages for future applications.

  12. Scanning ultrafast electron microscopy.

    Science.gov (United States)

    Yang, Ding-Shyue; Mohammed, Omar F; Zewail, Ahmed H

    2010-08-24

    Progress has been made in the development of four-dimensional ultrafast electron microscopy, which enables space-time imaging of structural dynamics in the condensed phase. In ultrafast electron microscopy, the electrons are accelerated, typically to 200 keV, and the microscope operates in the transmission mode. Here, we report the development of scanning ultrafast electron microscopy using a field-emission-source configuration. Scanning of pulses is made in the single-electron mode, for which the pulse contains at most one or a few electrons, thus achieving imaging without the space-charge effect between electrons, and still in ten(s) of seconds. For imaging, the secondary electrons from surface structures are detected, as demonstrated here for material surfaces and biological specimens. By recording backscattered electrons, diffraction patterns from single crystals were also obtained. Scanning pulsed-electron microscopy with the acquired spatiotemporal resolutions, and its efficient heat-dissipation feature, is now poised to provide in situ 4D imaging and with environmental capability.

  13. Scanning ultrafast electron microscopy

    Science.gov (United States)

    Yang, Ding-Shyue; Mohammed, Omar F.; Zewail, Ahmed H.

    2010-01-01

    Progress has been made in the development of four-dimensional ultrafast electron microscopy, which enables space-time imaging of structural dynamics in the condensed phase. In ultrafast electron microscopy, the electrons are accelerated, typically to 200 keV, and the microscope operates in the transmission mode. Here, we report the development of scanning ultrafast electron microscopy using a field-emission-source configuration. Scanning of pulses is made in the single-electron mode, for which the pulse contains at most one or a few electrons, thus achieving imaging without the space-charge effect between electrons, and still in ten(s) of seconds. For imaging, the secondary electrons from surface structures are detected, as demonstrated here for material surfaces and biological specimens. By recording backscattered electrons, diffraction patterns from single crystals were also obtained. Scanning pulsed-electron microscopy with the acquired spatiotemporal resolutions, and its efficient heat-dissipation feature, is now poised to provide in situ 4D imaging and with environmental capability. PMID:20696933

  14. Metamaterials for Ballistic Electrons

    CERN Document Server

    Dragoman, D; Dragoman, Daniela; Dragoman, Mircea

    2007-01-01

    The paper presents a metamaterial for ballistic electrons, which consists of a quantum barrier formed in a semiconductor with negative effective electron mass. This barrier is the analogue of a metamaterial for electromagnetic waves in media with negative electrical permittivity and magnetic permeability. Besides applications similar to those of optical metamaterials, a nanosized slab of a metamaterial for ballistic electrons, sandwiched between quantum wells of positive effective mass materials, reveals unexpected conduction properties, e.g. single or multiple room temperature negative differential conductance regions at very low voltages and with considerable peak-to-valley ratios, while the traversal time of ballistic electrons can be tuned to larger or smaller values than in the absence of the metamaterial slab. Thus, slow and fast electrons, analogous to slow and fast light, occur in metamaterials for ballistic electrons.

  15. Electrons in Nanostructures

    DEFF Research Database (Denmark)

    Flindt, Christian

    2007-01-01

    or a few electrons. Such few-electron devices are expected to form the building blocks of future electrical circuits and it is thus necessary to develop a thorough theoretical understanding of the physics of electrons in nanostructures. Re- garding applications there is a particular interest......-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......This thesis concerns theoretical aspects of electrons in man-made nanostruc- tures. Advances in nanofabrication technology during recent decades have made it possible to produce electrical devices on the nano-scale, whose func- tionality is determined by the quantum mechanical nature of a single...

  16. Single electron spintronics.

    Science.gov (United States)

    Dempsey, Kari J; Ciudad, David; Marrows, Christopher H

    2011-08-13

    Single electron electronics is now well developed, and allows the manipulation of electrons one-by-one as they tunnel on and off a nanoscale conducting island. In the past decade or so, there have been concerted efforts in several laboratories to construct single electron devices incorporating ferromagnetic components in order to introduce spin functionality. The use of ferromagnetic electrodes with a non-magnetic island can lead to spin accumulation on the island. On the other hand, making the dot also ferromagnetic introduces new physics such as tunnelling magnetoresistance enhancement in the cotunnelling regime and manifestations of the Kondo effect. Such nanoscale islands are also found to have long spin lifetimes. Conventional spintronics makes use of the average spin-polarization of a large ensemble of electrons: this new approach offers the prospect of accessing the quantum properties of the electron, and is a candidate approach to the construction of solid-state spin-based qubits.

  17. Electron transfer in proteins

    DEFF Research Database (Denmark)

    Farver, O; Pecht, I

    1991-01-01

    Electron migration between and within proteins is one of the most prevalent forms of biological energy conversion processes. Electron transfer reactions take place between active centers such as transition metal ions or organic cofactors over considerable distances at fast rates and with remarkable...... specificity. The electron transfer is attained through weak electronic interaction between the active sites, so that considerable research efforts are centered on resolving the factors that control the rates of long-distance electron transfer reactions in proteins. These factors include (in addition......-containing proteins. These proteins serve almost exclusively in electron transfer reactions, and as it turns out, their metal coordination sites are endowed with properties uniquely optimized for their function....

  18. Nanocrystals for electronics.

    Science.gov (United States)

    Panthani, Matthew G; Korgel, Brian A

    2012-01-01

    Semiconductor nanocrystals are promising materials for low-cost large-area electronic device fabrication. They can be synthesized with a wide variety of chemical compositions and size-tunable optical and electronic properties as well as dispersed in solvents for room-temperature deposition using various types of printing processes. This review addresses research progress in large-area electronic device applications using nanocrystal-based electrically active thin films, including thin-film transistors, light-emitting diodes, photovoltaics, and thermoelectrics.

  19. Technology of Electronic Signatur

    Directory of Open Access Journals (Sweden)

    Jaroslav Sadovsky

    2004-01-01

    Full Text Available An electronic signature uses a hash of message and an asymetrical algorithm of encryption for its generation. During verification of message on receiver side the hash of original message must be identical with the hash of received message. Electronic message is secured autentization of author and integrity of transmission date. By electronic signature it is possible to sign everything what is in digital form.

  20. Modern electronic materials

    CERN Document Server

    Watkins, John B

    2013-01-01

    Modern Electronic Materials focuses on the development of electronic components. The book first discusses the history of electronic components, including early developments up to 1900, developments up to World War II, post-war developments, and a comparison of present microelectric techniques. The text takes a look at resistive materials. Topics include resistor requirements, basic properties, evaporated film resistors, thick film resistors, and special resistors. The text examines dielectric materials. Considerations include basic properties, evaporated dielectric materials, ceramic dielectri

  1. Field emission electron source

    Science.gov (United States)

    Zettl, Alexander Karlwalter; Cohen, Marvin Lou

    2000-01-01

    A novel field emitter material, field emission electron source, and commercially feasible fabrication method is described. The inventive field emission electron source produces reliable electron currents of up to 400 mA/cm.sup.2 at 200 volts. The emitter is robust and the current it produces is not sensitive to variability of vacuum or the distance between the emitter tip and the cathode. The novel emitter has a sharp turn-on near 100 volts.

  2. Introduction to electronics

    CERN Document Server

    Korneff, Theodore

    1966-01-01

    Introduction to Electronics focuses on the study of electronics and electronic devices. Composed of 14 chapters, the book starts with discussions on dc circuits, including resistance, voltmeter, ammeter, galvanometer, internal resistance, and positive and negative currents. This topic is followed by discussions on ac circuits, particularly addressing voltage and current, average power, resistive load, complex plane, and parallel circuits. Discussions also focus on filters and tuned circuits, diodes, and power supplies. Particularly given attention are the processes, diagrams, and analyses

  3. ETHICS AND ELECTRONIC VOTING

    OpenAIRE

    2014-01-01

    13 pages; International audience; In the first part, we will define the main properties of a democratic election, providing a typology of electronic devices and give a view on some legal documents pertaining to the matter. In the second part, the ethics of voting will be evaluated: our methodology is detailed, followed by an examination of pure paper-based elections, paperless electronic voting and verifiable electronic voting. The new concept of legally operative transparency is defined and ...

  4. Electronic collection management

    CERN Document Server

    Mcginnis, Suzan D

    2013-01-01

    Build and manage your collection of digital resources with these successful strategies! This comprehensive volume is a practical guide to the art and science of acquiring and organizing electronic resources. The collections discussed here range in size from small college libraries to large research libraries, but all are facing similar problems: shrinking budgets, increasing demands, and rapidly shifting formats. Electronic Collection Management offers new ideas for coping with these issues. Bringing together diverse aspects of collection development, Electronic Collection

  5. Introduction to printed electronics

    CERN Document Server

    Suganuma, Katsuaki

    2014-01-01

    This book describes in detail modern technologies for printed electronics, explaining how nanotechnology and modern printing technology are merging to revolutionize electronics fabrication of thin, lightweight, large, and inexpensive products. Readers will benefit from the explanations of materials, devices and circuits used to design and implement the latest applications of printed electronics, such as thin flexible OLED displays, organic solar cells, OLED lighting, smart wallpaper, sensors, logic, memory and more.

  6. Electronic signal conditioning

    CERN Document Server

    NEWBY, BRUCE

    1994-01-01

    At technician level, brief references to signal conditioning crop up in a fragmented way in various textbooks, but there has been no single textbook, until now!More advanced texts do exist but they are more mathematical and presuppose a higher level of understanding of electronics and statistics. Electronic Signal Conditioning is designed for HNC/D students and City & Guilds Electronics Servicing 2240 Parts 2 & 3. It will also be useful for BTEC National, Advanced GNVQ, A-level electronics and introductory courses at degree level.

  7. Flying Electronic Warfare Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides NP-3D aircraft host platforms for Effectiveness of Navy Electronic Warfare Systems (ENEWS) Program antiship missile (ASM) seeker simulators used...

  8. Smart Electronic Textiles.

    Science.gov (United States)

    Weng, Wei; Chen, Peining; He, Sisi; Sun, Xuemei; Peng, Huisheng

    2016-05-17

    This Review describes the state-of-the-art of wearable electronics (smart textiles). The unique and promising advantages of smart electronic textiles are highlighted by comparing them with the conventional planar counterparts. The main kinds of smart electronic textiles based on different functionalities, namely the generation, storage, and utilization of electricity, are then discussed with an emphasis on the use of functional materials. The remaining challenges are summarized together with important new directions to provide some useful clues for the future development of smart electronic textiles.

  9. Electronic Wallets in Danger

    Directory of Open Access Journals (Sweden)

    Jean-Michel Sahut

    2006-10-01

    Full Text Available The erratic development of electronic wallets (EW illustrates thedifficulties of their adoption by the general public and shopkeepersalike. With exceptions, such as Proton in Europe and Octopus in Asia,a lot of electronic wallets are likely to disappear in the next fewyears. Yet the key factors of success are known by banks which oftenchoose to ignore them. However, the strategic change taken by some inorder to bring a fresh start to electronic wallets like Moneo couldreverse the tendency. Nevertheless, it will still be necessary to waitseveral years before seeing electronic wallets really imposethemselves as a credible alternative to payments in cash.

  10. Analytical Electron Microscope

    Data.gov (United States)

    Federal Laboratory Consortium — The Titan 80-300 is a transmission electron microscope (TEM) equipped with spectroscopic detectors to allow chemical, elemental, and other analytical measurements to...

  11. Fundamentals of electronics

    CERN Document Server

    Schubert, Thomas F

    2015-01-01

    This book, Electronic Devices and Circuit Application, is the first of four books of a larger work, Fundamentals of Electronics. It is comprised of four chapters describing the basic operation of each of the four fundamental building blocks of modern electronics: operational amplifiers, semiconductor diodes, bipolar junction transistors, and field effect transistors. Attention is focused on the reader obtaining a clear understanding of each of the devices when it is operated in equilibrium. Ideas fundamental to the study of electronic circuits are also developed in the book at a basic level to

  12. High-power electronics

    CERN Document Server

    Kapitsa, Petr Leonidovich

    1966-01-01

    High-Power Electronics, Volume 2 presents the electronic processes in devices of the magnetron type and electromagnetic oscillations in different systems. This book explores the problems of electronic energetics.Organized into 11 chapters, this volume begins with an overview of the motion of electrons in a flat model of the magnetron, taking into account the in-phase wave and the reverse wave. This text then examines the processes of transmission of electromagnetic waves of various polarization and the wave reflection from grids made of periodically distributed infinite metal conductors. Other

  13. Electron correlation in molecules

    CERN Document Server

    Wilson, S

    2007-01-01

    Electron correlation effects are of vital significance to the calculation of potential energy curves and surfaces, the study of molecular excitation processes, and in the theory of electron-molecule scattering. This text describes methods for addressing one of theoretical chemistry's central problems, the study of electron correlation effects in molecules.Although the energy associated with electron correlation is a small fraction of the total energy of an atom or molecule, it is of the same order of magnitude as most energies of chemical interest. If the solution of quantum mechanical equatio

  14. Flying Electronic Warfare Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides NP-3D aircraft host platforms for Effectiveness of Navy Electronic Warfare Systems (ENEWS) Program antiship missile (ASM) seeker simulators used...

  15. Electronics pocket book

    CERN Document Server

    Parr, E A

    1981-01-01

    Electronics Pocket Book, Fourth Edition is a nonmathematical presentation of the many varied topics covered by electronics. The book tackles electron physics, electronic components (i.e. resistors, capacitors, and conductors), integrated circuits, and the principles of a.c. and d.c. amplifiers. The text also discusses oscillators, digital circuits, digital computers, and optoelectronics (i.e., sensors, emitters, and devices that utilize light). Communications (such as line and radio communications, transmitters, receivers, and digital techniques); the principles and examples of servosystems; a

  16. Flexible Electronics Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Flexible Electronics Research Facility designs, synthesizes, tests, and fabricates materials and devices compatible with flexible substrates for Army information...

  17. Electron Transfer Chain Catalysis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    @@ Electron-transfer chain (ETC) catalysis belongs to the family of chain reactions where the electron is the catalyst. The ETC mechanism could be initiated by chemical activation, electrochemistry, or photolysis. If this pathway is applied to the preparation of organometallic complexes, it utilizes the greatly enhanced reactivity of organometallic 17e and 19e radicals. The chemical propagation is followed by the cross electron-transfer while the electron-transfer step is also followed by the chemical propagation, creating a loop in which reactants are facilely transformed into products. Interestingly the overall reaction is without any net redox change.

  18. Electron Transfer Chain Catalysis

    Institute of Scientific and Technical Information of China (English)

    LIU; LingKang

    2001-01-01

    Electron-transfer chain (ETC) catalysis belongs to the family of chain reactions where the electron is the catalyst. The ETC mechanism could be initiated by chemical activation, electrochemistry, or photolysis. If this pathway is applied to the preparation of organometallic complexes, it utilizes the greatly enhanced reactivity of organometallic 17e and 19e radicals. The chemical propagation is followed by the cross electron-transfer while the electron-transfer step is also followed by the chemical propagation, creating a loop in which reactants are facilely transformed into products. Interestingly the overall reaction is without any net redox change.  ……

  19. Nanosecond electron microscopes

    Science.gov (United States)

    Bostanjoglo; Elschner; Mao; Nink; Weingartner

    2000-04-01

    Combining electron optics, fast electronics and pulsed lasers, a transmission and a photoelectron emission microscope were built, which visualize events in thin films and on surfaces with a time resolution of several nanoseconds. The high-speed electron microscopy is capable to track fast laser-induced processes in metals below the ablation threshold, which are difficult to detect by other imaging techniques. The material response to nano- and femtosecond laser pulses was found to be very different. It was dominated by thermo/chemocapillary flow and chemical reactions in the case of nanosecond pulses, and by mechanical deformations and non-thermal electron emission after a femtosecond pulse.

  20. Electron caustic lithography

    Directory of Open Access Journals (Sweden)

    S. M. Kennedy

    2012-06-01

    Full Text Available A maskless method of electron beam lithography is described which uses the reflection of an electron beam from an electrostatic mirror to produce caustics in the demagnified image projected onto a resist–coated wafer. By varying the electron optics, e.g. via objective lens defocus, both the morphology and dimensions of the caustic features may be controlled, producing a range of bright and tightly focused projected features. The method is illustrated for line and fold caustics and is complementary to other methods of reflective electron beam lithography.

  1. Electronics circuits and systems

    CERN Document Server

    Bishop, Owen

    2011-01-01

    The material in Electronics - Circuits and Systems is a truly up-to-date textbook, with coverage carefully matched to the electronics units of the 2007 BTEC National Engineering and the latest AS and A Level specifications in Electronics from AQA, OCR and WJEC. The material has been organized with a logical learning progression, making it ideal for a wide range of pre-degree courses in electronics. The approach is student-centred and includes: numerous examples and activities; web research topics; Self Test features, highlighted key facts, formulae and definitions. Ea

  2. Electronics circuits and systems

    CERN Document Server

    Bishop, Owen

    2007-01-01

    The material in Electronics - Circuits and Systems is a truly up-to-date textbook, with coverage carefully matched to the electronics units of the 2007 BTEC National Engineering and the latest AS and A Level specifications in Electronics from AQA, OCR and WJEC. The material has been organized with a logical learning progression, making it ideal for a wide range of pre-degree courses in electronics. The approach is student-centred and includes: numerous examples and activities; web research topics; Self Test features, highlighted key facts, formulae and definitions. Each chapter ends with a set

  3. (Pulsed electron beam precharger)

    Energy Technology Data Exchange (ETDEWEB)

    Finney, W.C. (ed.); Shelton, W.N.

    1990-01-01

    This report discusses the following topics on electron beam guns: Precharger Modification; Installation of Charge vs. Radius Apparatus; High Concentration Aerosol Generation; and Data Acquisition and Analysis System.

  4. Electronic circuits fundamentals & applications

    CERN Document Server

    Tooley, Mike

    2015-01-01

    Electronics explained in one volume, using both theoretical and practical applications.New chapter on Raspberry PiCompanion website contains free electronic tools to aid learning for students and a question bank for lecturersPractical investigations and questions within each chapter help reinforce learning Mike Tooley provides all the information required to get to grips with the fundamentals of electronics, detailing the underpinning knowledge necessary to appreciate the operation of a wide range of electronic circuits, including amplifiers, logic circuits, power supplies and oscillators. The

  5. Electronics Environmental Benefits Calculator

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Electronics Environmental Benefits Calculator (EEBC) was developed to assist organizations in estimating the environmental benefits of greening their purchase,...

  6. Electronic Service Statistics - Quarterly Report

    Data.gov (United States)

    Social Security Administration — This is a quarterly report that compares electronic data vs non-electronic data for electronic services. Report contains six main sections namely, electronic access,...

  7. Optical Electronics. Electronics Module 9. Instructor's Guide.

    Science.gov (United States)

    Franken, Bill

    This module is the ninth of 10 modules in the competency-based electronics series. Introductory materials include a listing of competencies addressed in the module, a parts/equipment list, and a cross reference table of instructional materials. Five instructional units cover: fiber optic cable; optical coupler; lasers and masers; optical displays;…

  8. Notes on Electronic Lexicography

    CERN Document Server

    Parvanov, Yavor

    2011-01-01

    These notes are a continuation of topics covered by V. Selegej in his article "Electronic Dictionaries and Computational lexicography". How can an electronic dictionary have as its object the description of closely related languages? Obviously, such a question allows multiple answers.

  9. Managing electronic records

    CERN Document Server

    McLeod, Julie

    2005-01-01

    For records management courses, this book covers the theory and practice of managing electronic records as business and information assets. It focuses on the strategies, systems and procedures necessary to ensure that electronic records are appropriately created, captured, organized and retained over time to meet business and legal requirements.

  10. STEP electronic system design

    Science.gov (United States)

    Couch, R. H.; Johnson, J. W.

    1984-01-01

    The STEP electronic system design is discussed. The purpose of the design is outlined. The electronic system design is summarized and it is found that: an effective conceptual system design is developed; the design represents a unique set of capabilities; makes efficient use of available orbiter resources; the system capabilities exceed identified potential experiment needs.

  11. Electron tunnel sensor technology

    Science.gov (United States)

    Waltman, S. B.; Kaiser, W. J.

    1989-01-01

    The recent development of Scanning Tunneling Microscopy technology allows the application of electron tunneling to position detectors for the first time. The vacuum tunnel junction is one of the most sensitive position detection mechanisms available. It is also compact, simple, and requires little power. A prototype accelerometer based on electron tunneling, and other sensor applications of this promising new technology are described.

  12. Electron scattering violates parity

    CERN Multimedia

    2004-01-01

    Parity violation has been observed in collisions between electrons at the Stanford Linear Accelerator Center (SLAC) in the US. The resuls, which are in agreement with the Stanford Model of particle physics, also provide a new measurement of the weak charge of the electron (½ page)

  13. Pulsed Plasma Electron Sources

    Science.gov (United States)

    Krasik, Yakov

    2008-11-01

    Pulsed (˜10-7 s) electron beams with high current density (>10^2 A/cm^2) are generated in diodes with electric field of E > 10^6 V/cm. The source of electrons in these diodes is explosive emission plasma, which limits pulse duration; in the case E Hadas and Ya. E. Krasik, Europhysics Lett. 82, 55001 (2008).

  14. Electron transfer in peptides.

    Science.gov (United States)

    Shah, Afzal; Adhikari, Bimalendu; Martic, Sanela; Munir, Azeema; Shahzad, Suniya; Ahmad, Khurshid; Kraatz, Heinz-Bernhard

    2015-02-21

    In this review, we discuss the factors that influence electron transfer in peptides. We summarize experimental results from solution and surface studies and highlight the ongoing debate on the mechanistic aspects of this fundamental reaction. Here, we provide a balanced approach that remains unbiased and does not favor one mechanistic view over another. Support for a putative hopping mechanism in which an electron transfers in a stepwise manner is contrasted with experimental results that support electron tunneling or even some form of ballistic transfer or a pathway transfer for an electron between donor and acceptor sites. In some cases, experimental evidence suggests that a change in the electron transfer mechanism occurs as a result of donor-acceptor separation. However, this common understanding of the switch between tunneling and hopping as a function of chain length is not sufficient for explaining electron transfer in peptides. Apart from chain length, several other factors such as the extent of the secondary structure, backbone conformation, dipole orientation, the presence of special amino acids, hydrogen bonding, and the dynamic properties of a peptide also influence the rate and mode of electron transfer in peptides. Electron transfer plays a key role in physical, chemical and biological systems, so its control is a fundamental task in bioelectrochemical systems, the design of peptide based sensors and molecular junctions. Therefore, this topic is at the heart of a number of biological and technological processes and thus remains of vital interest.

  15. Single particle electron microscopy

    NARCIS (Netherlands)

    Boekema, Egbert J.; Folea, Mihaela; Kouril, Roman; Kouřil, Roman

    2009-01-01

    Electron microscopy (EM) in combination with image analysis is a powerful technique to study protein structures at low, medium, and high resolution. Since electron micrographs of biological objects are very noisy, improvement of the signal-to-noise ratio by image processing is an integral part of EM

  16. Electronic Mail Connections.

    Science.gov (United States)

    Tucker, Susan A.

    1987-01-01

    Provides an overview of new developments in electronic mail, including the interconnection of online networks, some on an international level; and news on system upgrades of specific information services. The growth of the electronic mail industry and possible future trends are discussed and a glossary of technical terms is included. (CLB)

  17. Electronically Controlled Resistor Bank

    Science.gov (United States)

    Ross, Walter L.

    1987-01-01

    Resistance quickly varied in small steps over wide range. Device with no moving parts provides variable electrical resistance. Used with analog or digital circuity to provide electronic selection of large number of resistance values for testing, simulation, control, or other purposes. Nearest electromechanical equivalent of all-electronic device is potentiometer driven by servomotor.

  18. Electronics and Lithuanian Terminology

    Directory of Open Access Journals (Sweden)

    Stasys Zajankauskas

    2011-04-01

    Full Text Available It is found that the vacuum triode, transistor, monolithic circuit and microprocessor were the most important inventions of traditional electronics. Thus, the origins of the traditional electronics should be associated with the invention of the vacuum triode, but not with the invention of vacuum diode. It is shown that the science of electronics is not as young as computer science or up-to-date information technologies: electronics, including active electronics, had already celebrated the centenary, and the period of 2004–2008 is the period of numerous already solid jubilees. Thus, the terminology of electronics is not at initial stage of evolution as well – general terms should be already systematized and normalized. However, Lithuanian terms for electronic devices invented before tens of years and terms for old-defined notions associated with these devices are still varying, some are worsened. Especially, the incorrectly motivated terms used for variations of transistors and microcircuits are analyzed in the article. It is motivated which terms are preferable, systematic and exact. The paper is dedicated to the 50th anniversary of monolithic circuit, as well as the 60th anniversary of transistor, the 40th jubilee of microprocessor and centenary of electronics.

  19. Electronically Induced Phase Transformations

    Science.gov (United States)

    1980-12-01

    ries (w hen the Slater free-electron exchange is used). A systematic the active researcher. study of relativistic electron densities and isomer...comp:wrees aux mesures actuelles d’effet dHvA d’Arko et Schirber. Le calu; du facteur de forme neutronique en presence d’un champ magnetique est en bon

  20. Green and biodegradable electronics

    Directory of Open Access Journals (Sweden)

    Mihai Irimia-Vladu

    2012-07-01

    Full Text Available We live in a world where the lifetime of electronics is becoming shorter, now approaching an average of several months. This poses a growing ecological problem. This brief review will present some of the initial steps taken to address the issue of electronic waste with biodegradable organic electronic materials. Many organic materials have been shown to be biodegradable, safe, and nontoxic, including compounds of natural origin. Additionally, the unique features of such organic materials suggest they will be useful in biofunctional electronics; demonstrating functions that would be inaccessible for traditional inorganic compounds. Such materials may lead to fully biodegradable and even biocompatible/biometabolizable electronics for many low-cost applications. This review highlights recent progress in these classes of material, covering substrates and insulators, semiconductors, and finally conductors.

  1. LEIR electron cooler status

    CERN Document Server

    Tranquille, G; Parkhomchuk, V; Prieto, V; Sautier, R

    2006-01-01

    The electron cooler for LEIR is the first of a new generation of coolers being commissioned for fast phase space cooling of ion beams in storage rings. It is a stateof- the-art cooler incorporating all the recent developments in electron cooling technology (adiabatic expansion, electrostatic bend, variable density electron beam) and is designed to deliver up to 600 mA of electron current for the cooling and stacking of Pb54+ ions in the frame of the ions for LHC project. In this paper we present our experience with the commissioning of the new device as well as the first results of ion beam cooling with a high-intensity variable-density electron beam.

  2. Electron Cyclotron Emission Radiometer

    Science.gov (United States)

    Morales, Cristina

    2009-11-01

    There is much interest in studying plasmas that generate hot electrons. The goal of this project is to develop a wide band electron cyclotron radiometer to measure the non-Maxwellian rapid rises in electron temperature. These rapid increases in temperature will then be correlated to instabilities in the plasma. This project explores a type of noncontact temperature measurement. We will attempt to show the feasibility of electron cyclotron emissions to measure the Maryland Centrifugal Experiment's electron plasma temperature. The radiometer has been designed to have 100dB of gain and a sensitivity of 24mV/dB given by its logarithmic amplifier. If successful, this radiometer will be used as a diagnostic tool in later projects such as the proposed experiment studying magnetic reconnection using solar flux loops.

  3. Practical electronics for inventors

    CERN Document Server

    Scherz, Paul

    2013-01-01

    Spark your creativity and gain the electronics skills required to transform your innovative ideas into functioning gadgets. This hands-on, updated guide outlines electrical principles and provides thorough, easy-to-follow instructions, schematics, and illustrations. Findout how to select components, safely assemble circuits, perform error tests, and build plug-and-play prototypes. Practical Electronics for Inventors, Third Edition, features all-new chapters on sensors, microcontrollers, modular electronics, and the latest software tools. Coverage includes: Resistors, capacitors, inductors, and transformers Diodes, transistors, and integrated circuits Optoelectronics, solar cells, and phototransistors Sensors, GPS modules, and touch screens Op amps, regulators, and power supplies Digital electronics, LCD displays, and logic gates Microcontrollers and prototyping platforms, including Arduino DC motors, RC servos, and stepper motors Microphones, audio amps, and speakers Modular electronics and prototyping.

  4. Simulations of Gaussian electron guns for RHIC electron lens

    Energy Technology Data Exchange (ETDEWEB)

    Pikin, A. [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.

    2014-02-28

    Simulations of two versions of the electron gun for RHIC electron lens are presented. The electron guns have to generate an electron beam with Gaussian radial profile of the electron beam density. To achieve the Gaussian electron emission profile on the cathode we used a combination of the gun electrodes and shaping of the cathode surface. Dependence of electron gun performance parameters on the geometry of electrodes and the margins for electrodes positioning are presented.

  5. Electronic Collection Management and Electronic Information Services

    Science.gov (United States)

    2003-04-01

    TITLE: Electronic Information Management for PfP Nations [La gestion electronique des informations pour les pays du PfP] To order the complete...banking and securities trading. E- commerce has moved into many other areas and it is now possible to purchase a wide variety of goods and services on line...include interactive e- commerce and e-governance services as well as various organizational database management needs (including registrations, membership

  6. Electron Cooling of RHIC

    CERN Document Server

    Ben-Zvi, Ilan; Barton, Donald; Beavis, Dana; Blaskiewicz, Michael; Bluem, Hans; Brennan, Joseph M; Bruhwiler, David L; Burger, Al; Burov, Alexey; Burrill, Andrew; Calaga, Rama; Cameron, Peter; Chang, Xiangyun; Cole, Michael; Connolly, Roger; Delayen, Jean R; Derbenev, Yaroslav S; Eidelman, Yury I; Favale, Anthony; Fedotov, Alexei V; Fischer, Wolfram; Funk, L W; Gassner, David M; Hahn, Harald; Harrison, Michael; Hershcovitch, Ady; Holmes, Douglas; Hseuh Hsiao Chaun; Johnson, Peter; Kayran, Dmitry; Kewisch, Jorg; Kneisel, Peter; Koop, Ivan; Lambiase, Robert; Litvinenko, Vladimir N; MacKay, William W; Mahler, George; Malitsky, Nikolay; McIntyre, Gary; Meng, Wuzheng; Merminga, Lia; Meshkov, Igor; Mirabella, Kerry; Montag, Christoph; Nagaitsev, Sergei; Nehring, Thomas; Nicoletti, Tony; Oerter, Brian; Parkhomchuk, Vasily; Parzen, George; Pate, David; Phillips, Larry; Preble, Joseph P; Rank, Jim; Rao, Triveni; Rathke, John; Roser, Thomas; Russo, Thomas; Scaduto, Joseph; Schultheiss, Tom; Sekutowicz, Jacek; Shatunov, Yuri; Sidorin, Anatoly O; Skrinsky, Aleksander Nikolayevich; Smirnov, Alexander V; Smith, Kevin T; Todd, Alan M M; Trbojevic, Dejan; Troubnikov, Grigory; Wang, Gang; Wei, Jie; Williams, Neville; Wu, Kuo-Chen; Yakimenko, Vitaly; Zaltsman, Alex; Zhao, Yongxiang; ain, Animesh K

    2005-01-01

    We report progress on the R&D program for electron-cooling of the Relativistic Heavy Ion Collider (RHIC). This electron cooler is designed to cool 100 GeV/nucleon at storage energy using 54 MeV electrons. The electron source will be a superconducting RF photocathode gun. The accelerator will be a superconducting energy recovery linac. The frequency of the accelerator is set at 703.75 MHz. The maximum electron bunch frequency is 9.38 MHz, with bunch charge of 20 nC. The R&D program has the following components: The photoinjector and its photocathode, the superconducting linac cavity, start-to-end beam dynamics with magnetized electrons, electron cooling calculations including benchmarking experiments and development of a large superconducting solenoid. The photoinjector and linac cavity are being incorporated into an energy recovery linac aimed at demonstrating ampere class current at about 20 MeV. A Zeroth Order Design Report is in an advanced draft state, and can be found on the web at http://www.ags...

  7. Dissociative Electron Attachment

    Science.gov (United States)

    Arreola, Esmeralda; Esmeralda Arreola Collaboration; Leigh Hargreaves Collaboration

    Since the pioneering work of Boudiaffa et al., it has been understood that electrons, even with energies near or below the ionization threshold, are capable of initiating strand-breaks in human DNA. This discovery raised important questions for cancer treatments, since sub-ionizing electrons are known to be the most copiously produced secondary product of radiation therapy. But even to date these factors are largely excluded from dosimetry calculations. This lack of inclusion is, at least in part, certainly due to the dearth of fundamental data describing low-energy electron interactions with nucleotide molecules that form the basis of DNA. Understanding of how such slow electrons are able to damage DNA remains incomplete, but the strongly peaked nature of Boudiaffa et al.'s data gives strong hints at resonantly driven collision processes. DNA damage is therefore most likely driven by ``dissociative electron attachment'' (DEA). DEA is a rather complicated process to model due to the coupling of electronic and nuclear degrees of freedom in the molecule. At the California State University Fullerton, we are currently commissioning a new spectrometer to study dissociation channels, reaction rates and orientation effects in DEA collisions between slow electrons and nucleotide molecules. At the meeting we will present design parameters and commissioning data for this new apparatus.

  8. Electron heat flux instability

    Science.gov (United States)

    Saeed, Sundas; Sarfraz, M.; Yoon, P. H.; Lazar, M.; Qureshi, M. N. S.

    2017-02-01

    The heat flux instability is an electromagnetic mode excited by a relative drift between the protons and two-component core-halo electrons. The most prominent application may be in association with the solar wind where drifting electron velocity distributions are observed. The heat flux instability is somewhat analogous to the electrostatic Buneman or ion-acoustic instability driven by the net drift between the protons and bulk electrons, except that the heat flux instability operates in magnetized plasmas and possesses transverse electromagnetic polarization. The heat flux instability is also distinct from the electrostatic counterpart in that it requires two electron species with relative drifts with each other. In the literature, the heat flux instability is often called the 'whistler' heat flux instability, but it is actually polarized in the opposite sense to the whistler wave. This paper elucidates all of these fundamental plasma physical properties associated with the heat flux instability starting from a simple model, and gradually building up more complexity towards a solar wind-like distribution functions. It is found that the essential properties of the instability are already present in the cold counter-streaming electron model, and that the instability is absent if the protons are ignored. These instability characteristics are highly reminiscent of the electron firehose instability driven by excessive parallel temperature anisotropy, propagating in parallel direction with respect to the ambient magnetic field, except that the free energy source for the heat flux instability resides in the effective parallel pressure provided by the counter-streaming electrons.

  9. Aerogels for electronics

    Energy Technology Data Exchange (ETDEWEB)

    Hrubesh, L.W.

    1994-10-01

    In addition to their other exceptional properties, aerogels also exhibit unusual dielectric and electronic properties due to their nano-sized structures and high porosities. For example, aerogels have the lowest dielectric constants measured for a solid material (having values approaching 1.0); they have exceptionally high dielectric resistivities and strengths (i.e., ability to insulate very high voltages); they exhibit low dielectric loss at microwave frequencies; and some aerogels are electrically conductive and photoconductive. These properties are being exploited to provide the next generation of materials for energy storage, low power consumption, and ultra-fast electronics. We are working toward adapting these unusual materials for microelectronic applications, particularly, making thin aerogel films for dielectric substrates and for energy storage devices such as supercapacitors. Measurements are presented in this paper for the dielectric and electronic properties of aerogels, including the dielectric constant, loss factor, dielectric and electrical conductivity, volume resistivity, and dielectric strength. We also describe methods to form and characterize thin aerogel films which are being developed for numerous electronic applications. Finally, some of the electronic applications proposed for aerogels are presented. Commercialization of aerogels for electronics must await further feasibility, prototype development, and cost studies, but they are one of the key materials and are sure to have a major impact on future electronics.

  10. Coherent electron cooling

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko,V.

    2009-05-04

    Cooling intense high-energy hadron beams remains a major challenge in modern accelerator physics. Synchrotron radiation is still too feeble, while the efficiency of two other cooling methods, stochastic and electron, falls rapidly either at high bunch intensities (i.e. stochastic of protons) or at high energies (e-cooling). In this talk a specific scheme of a unique cooling technique, Coherent Electron Cooling, will be discussed. The idea of coherent electron cooling using electron beam instabilities was suggested by Derbenev in the early 1980s, but the scheme presented in this talk, with cooling times under an hour for 7 TeV protons in the LHC, would be possible only with present-day accelerator technology. This talk will discuss the principles and the main limitations of the Coherent Electron Cooling process. The talk will describe the main system components, based on a high-gain free electron laser driven by an energy recovery linac, and will present some numerical examples for ions and protons in RHIC and the LHC and for electron-hadron options for these colliders. BNL plans a demonstration of the idea in the near future.

  11. Electronic devices and circuits

    CERN Document Server

    Pridham, Gordon John

    1968-01-01

    Electronic Devices and Circuits, Volume 1 deals with the design and applications of electronic devices and circuits such as passive components, diodes, triodes and transistors, rectification and power supplies, amplifying circuits, electronic instruments, and oscillators. These topics are supported with introductory network theory and physics. This volume is comprised of nine chapters and begins by explaining the operation of resistive, inductive, and capacitive elements in direct and alternating current circuits. The theory for some of the expressions quoted in later chapters is presented. Th

  12. Power Electronics for Microgrids

    DEFF Research Database (Denmark)

    Dragicevic, Tomislav; Blaabjerg, Frede

    2016-01-01

    A microgrid (MG) is a stand-alone or grid-connected hybrid renewable system that uses distributed renewable and nonrenewable energy sources and energy storage systems (ESSs) to supply power to local loads. The system is ordinarily based on power electronics, with interface converters allowing...... a continuous supply of power in the presence of variable RES production. This chapter describes some specific features of DC MGs in terms of power architecture, control, and protection. It also reviews several uncommon power electronic interfaces. Regarding control, operation without critical communication...... are explained in this chapter. The chapter concludes with a review of power electronic intensive protection solutions for DC MGs....

  13. Quantum electronics basic theory

    CERN Document Server

    Fain, V M; Sanders, J H

    1969-01-01

    Quantum Electronics, Volume 1: Basic Theory is a condensed and generalized description of the many research and rapid progress done on the subject. It is translated from the Russian language. The volume describes the basic theory of quantum electronics, and shows how the concepts and equations followed in quantum electronics arise from the basic principles of theoretical physics. The book then briefly discusses the interaction of an electromagnetic field with matter. The text also covers the quantum theory of relaxation process when a quantum system approaches an equilibrium state, and explai

  14. Electronic components and systems

    CERN Document Server

    Dennis, W H

    2013-01-01

    Electronic Components and Systems focuses on the principles and processes in the field of electronics and the integrated circuit. Covered in the book are basic aspects and physical fundamentals; different types of materials involved in the field; and passive and active electronic components such as capacitors, inductors, diodes, and transistors. Also covered in the book are topics such as the fabrication of semiconductors and integrated circuits; analog circuitry; digital logic technology; and microprocessors. The monograph is recommended for beginning electrical engineers who would like to kn

  15. Consulting in Electronic Commerce

    Directory of Open Access Journals (Sweden)

    Florentina Loredana Tache

    2010-10-01

    Full Text Available Economic development of electronic services provide advice and many agents of existingreferral systems to recommend and provide products, information and customized views of thecommunity through a personalized interaction in real time. Distributed systems of autonomous agentsare becoming increasingly important in electronic comet because the basic decisions of agents adviceon trust and reputation are taken in a similar way human society. If these decisions will be as a realconsumer protection, when new aspects of online consumer legislation will become usefulinformation in advice and consulting of electronic commerce.

  16. Electron Beam Materials Irradiators

    Science.gov (United States)

    Cleland, Marshall R.

    2012-06-01

    Radiation processing is a well established method for enhancing the properties of materials and commercial products by treating them with ionizing energy in the form of high-energy electrons, X-rays, and gamma rays. Beneficial effects include polymerizing, cross-linking, grafting and degrading plastics, sterilizing single-use medical devices, disinfecting and disinfesting fresh foods, purifying drinking water, treating wastewater and other toxic waste materials that harm the environment, and many other applications that are still being evaluated. Industrial electron accelerators of several types have been developed and are being used for these applications. More than 1800 electron accelerators are presently installed in facilities worldwide for these purposes.

  17. Field emission electronics

    CERN Document Server

    Egorov, Nikolay

    2017-01-01

    This book is dedicated to field emission electronics, a promising field at the interface between “classic” vacuum electronics and nanotechnology. In addition to theoretical models, it includes detailed descriptions of experimental and research techniques and production technologies for different types of field emitters based on various construction principles. It particularly focuses on research into and production of field cathodes and electron guns using recently developed nanomaterials and carbon nanotubes. Further, it discusses the applications of field emission cathodes in new technologies such as light sources, flat screens, microwave and X-ray devices.

  18. Semiconductor opto-electronics

    CERN Document Server

    Moss, TS; Ellis, B

    1972-01-01

    Semiconductor Opto-Electronics focuses on opto-electronics, covering the basic physical phenomena and device behavior that arise from the interaction between electromagnetic radiation and electrons in a solid. The first nine chapters of this book are devoted to theoretical topics, discussing the interaction of electromagnetic waves with solids, dispersion theory and absorption processes, magneto-optical effects, and non-linear phenomena. Theories of photo-effects and photo-detectors are treated in detail, including the theories of radiation generation and the behavior of semiconductor lasers a

  19. Principles of quantum electronics

    CERN Document Server

    Marcuse, Dietrich

    1980-01-01

    Principles of Quantum Electronics focuses on the concept of quantum electronics as the application of quantum theory to engineering problems. It examines the principles that govern specific quantum electronics devices and presents their theoretical applications to typical problems. Comprised of 10 chapters, this book starts with an overview of the Dirac formulation of quantum mechanics. This text then considers the derivation of the formalism of field quantization and discusses the properties of photons and phonons. Other chapters examine the interaction between the electromagnetic field and c

  20. VLSI electronics microstructure science

    CERN Document Server

    1982-01-01

    VLSI Electronics: Microstructure Science, Volume 4 reviews trends for the future of very large scale integration (VLSI) electronics and the scientific base that supports its development.This book discusses the silicon-on-insulator for VLSI and VHSIC, X-ray lithography, and transient response of electron transport in GaAs using the Monte Carlo method. The technology and manufacturing of high-density magnetic-bubble memories, metallic superlattices, challenge of education for VLSI, and impact of VLSI on medical signal processing are also elaborated. This text likewise covers the impact of VLSI t

  1. Coding for Electronic Mail

    Science.gov (United States)

    Rice, R. F.; Lee, J. J.

    1986-01-01

    Scheme for coding facsimile messages promises to reduce data transmission requirements to one-tenth current level. Coding scheme paves way for true electronic mail in which handwritten, typed, or printed messages or diagrams sent virtually instantaneously - between buildings or between continents. Scheme, called Universal System for Efficient Electronic Mail (USEEM), uses unsupervised character recognition and adaptive noiseless coding of text. Image quality of resulting delivered messages improved over messages transmitted by conventional coding. Coding scheme compatible with direct-entry electronic mail as well as facsimile reproduction. Text transmitted in this scheme automatically translated to word-processor form.

  2. TIS - Beyond Electronic Mail.

    Science.gov (United States)

    1979-01-01

    AD-AI06 764 AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH F/G 17/2 TIS - BEYOND ELECTRONIC MAIL .(U) 1979 D L OLSON, N T FLYNN, M I DARWISH...79-22§1_ 4~~~~~~~ SIXi.m.aihl -- . TYPE OF REPORT & PERIOD covERED TIS -SBeyond Electronic Mail . TlSS~cnA~r 6 PEFRI4 O11G. REPORT NUMBER Duane L.A:o...single-service provisions of so-called " electronic mail ." Approaches to be used in implementing a TIS are considered, and a time-frame scenario is

  3. Electron paramagnetic resonance

    CERN Document Server

    Al'tshuler, S A

    2013-01-01

    Electron Paramagnetic Resonance is a comprehensive text on the field of electron paramagnetic resonance, covering both the theoretical background and the results of experiment. This book is composed of eight chapters that cover theoretical materials and experimental data on ionic crystals, since these are the materials that have been most extensively studied by the methods of paramagnetic resonance. The opening chapters provide an introduction to the basic principles of electron paramagnetic resonance and the methods of its measurement. The next chapters are devoted to the theory of spectra an

  4. Reliable Electronic Equipment

    Directory of Open Access Journals (Sweden)

    N. A. Nayak

    1960-05-01

    Full Text Available The reliability aspect of electronic equipment's is discussed. To obtain optimum results, close cooperation between the components engineer, the design engineer and the production engineer is suggested.

  5. The art of electronics

    CERN Document Server

    Horowitz, Paul

    2015-01-01

    At long last, here is the thoroughly revised and updated third edition of the hugely successful Art of Electronics. It is widely accepted as the best single authoritative book on electronic circuit design. In addition to new or enhanced coverage of many topics, the Third Edition includes: 90 oscilloscope screenshots illustrating the behavior of working circuits; dozens of graphs giving highly useful measured data of the sort that's often buried or omitted in datasheets but which you need when designing circuits; 80 tables (listing some 1650 active components), enabling intelligent choice of circuit components by listing essential characteristics (both specified and measured) of available parts. The new Art of Electronics ​​retains the feeling of informality and easy access that helped make the earlier editions so successful and popular. It is an indispensable reference and the gold standard​​ for anyone, student or researcher, professional or amateur, who works with electronic circuits.

  6. Electronic Universal Vote

    Directory of Open Access Journals (Sweden)

    Cristian USCATU

    2008-01-01

    Full Text Available In the days of informational society everything is going online. Most aspects of our lives have online components. Since democracy is a big issue, it could not escape this trend. Governments themselves are moving to the online environment for the purpose of improving their internal efficiency and their availability to the citizens, businesses and other parties interested. Since governments are the result of elections, elections have also been touched by the electronic fever. New electronic voting solutions arise and each one brings new debates with many arguments in their favor and against them. Accessibility and ease of use leads the arguments in favor of electronic voting over the internet, while fear of fraud is the main reason people are avoiding electronics and clinging on classic paper ballots.

  7. Electron gun for SSRF

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A 100 kV triode-electron-gun has been designed and manufactured for the Linac of Shanghai Synchrotron Radiation Facility (SSRF). In this paper the performance of the gun and some key components are described.

  8. Pulsed plasma electron sourcesa)

    Science.gov (United States)

    Krasik, Ya. E.; Yarmolich, D.; Gleizer, J. Z.; Vekselman, V.; Hadas, Y.; Gurovich, V. Tz.; Felsteiner, J.

    2009-05-01

    There is a continuous interest in research of electron sources which can be used for generation of uniform electron beams produced at E ≤105 V/cm and duration ≤10-5 s. In this review, several types of plasma electron sources will be considered, namely, passive (metal ceramic, velvet and carbon fiber with and without CsI coating, and multicapillary and multislot cathodes) and active (ferroelectric and hollow anodes) plasma sources. The operation of passive sources is governed by the formation of flashover plasma whose parameters depend on the amplitude and rise time of the accelerating electric field. In the case of ferroelectric and hollow-anode plasma sources the plasma parameters are controlled by the driving pulse and discharge current, respectively. Using different time- and space-resolved electrical, optical, spectroscopical, Thomson scattering and x-ray diagnostics, the parameters of the plasma and generated electron beam were characterized.

  9. Scanning Auger Electron Microscope

    Data.gov (United States)

    Federal Laboratory Consortium — A JEOL model 7830F field emission source, scanning Auger microscope. Specifications / Capabilities: Ultra-high vacuum (UHV), electron gun range from 0.1 kV to 25 kV,...

  10. Scanning Auger Electron Microscope

    Data.gov (United States)

    Federal Laboratory Consortium — A JEOL model 7830F field emission source, scanning Auger microscope.Specifications / Capabilities:Ultra-high vacuum (UHV), electron gun range from 0.1 kV to 25 kV,...

  11. Telecommunications--Electronic Mail.

    Science.gov (United States)

    Kelly, Luke E.; Zuckerman, B. Michael

    1989-01-01

    This article identifies resources needed in order for physical education, recreation, and dance professionals to use computer-based telecommunications; discusses electronic mail; and explains how telecommunications can enhance communication in the field, both within and across professions. (IAH)

  12. Introduction to electron crystallography.

    Science.gov (United States)

    Kühlbrandt, Werner

    2013-01-01

    From the earliest work on regular arrays in negative stain, electron crystallography has contributed greatly to our understanding of the structure and function of biological macromolecules. The development of electron cryo-microscopy (cryo-EM) then lead to the first groundbreaking atomic models of the membrane proteins bacteriorhodopsin and light harvesting complex II within lipid bilayers. Key contributions towards cryo-EM and electron crystallography methods included specimen preparation and vitrification, liquid-helium cooling, data collection, and image processing. These methods are now applied almost routinely to both membrane and soluble proteins. Here we outline the advances and the breakthroughs that paved the way towards high-resolution structures by electron crystallography, both in terms of methods development and biological milestones.

  13. Electron and Photon ID

    CERN Document Server

    Hryn'ova, Tetiana; The ATLAS collaboration

    2017-01-01

    The identification of prompt photons and the rejection of background coming mostly from photons from hadron decays relies on the high granularity of the ATLAS calorimeter. The electron identification used in ATLAS for run 2 is based on a likelihood discrimination to separate isolated electron candidates from candidates originating from photon conversions, hadron misidentification and heavy flavor decays. In addition, isolation variables are used as further handles to separate signal and background. Several methods are used to measure with data the efficiency of the photon identification requirements, to cover a broad energy spectrum. At low energy, photons from radiative Z decays are used. In the medium energy range, similarities between electrons and photon showers are exploited using Z->ee decays. At high energy, inclusive photon samples are used. The measurement of the efficiencies of the electron identification and isolation cuts are performed with the data using tag and probe techniques with large statis...

  14. Electronics Modernization Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Current electronic packaging designs used in our most recent spacecraft are comprised of technologies from the 1980’s and 1990’s. The current approach...

  15. Electronics for guitarists

    CERN Document Server

    Dailey, Denton J

    2014-01-01

    Electronics for Guitarists focuses on analog circuitry, and is written for the guitarist interested in transistor and vacuum tube-based amplifiers. Topics include discrete transistors and diodes, classical filter circuits, and vacuum tube-based amplifiers.

  16. ELECTRONIC BANKING AND ELECTRONIC COMMERCE IN SERBIA

    Directory of Open Access Journals (Sweden)

    Ivana B. Petrevska

    2014-10-01

    Full Text Available Nowadays, we may witness to dramatic and visible changes in our life environment. Business ambient for companies is different every day, and it is very hard to predict a direction of future changes. There is an environment characterized by sharp competition and increasing number of competitors, fast technological improvements and highly sophisticated and informed costumers. Technological process influences the humanity strongly, changing the way that people live, work and spend. Electronic commerce and electronic banking has become incontinent, and makes a great part of today's total transactions. There are an increasing number of companies that perform their business that way and make profit. Social networks are proven to be the least expensive way of information exchange, and they are present in almost every part of the world. The globalization has reached the most distant parts of the Earth. Every resistance to new technologies is dangerous and may lead to bankruptcy. Due to the EU expansion, Internet users are to be expected, and prosperity of the e-commerce business models at the same time. In Serbia, electronic commerce is present, but not as developed as in EU countries. E-commerce, however it might be successful throughout the world, it is somewhat slow in its growth in Serbia. The reasons are numerous, and main obstacles are the lack of trust, still limited usage of banking cards, avoiding of e-payments by older population etc. Also, the recent scandals over the misuse of personal data, and e-crime are discouraging factors for the growth of e-trade and ebanking. The younger generations are ever more ready to use e-commerce, since they are open to new technologies and do not have the defensive attitude towards it. E-commerce and e-banking has growing potential even among older population, if the society prevents them from fear and mistrust.

  17. Cooling of electronic equipment

    DEFF Research Database (Denmark)

    A. Kristensen, Anders Schmidt

    2003-01-01

    Cooling of electronic equipment is studied. The design size of electronic equipment decrease causing the thermal density to increase. This affect the cooling which can cause for example failures of critical components due to overheating or thermal induced stresses. Initially a pin fin heat sink...... is considered as extruded profiles are inadequate for compact designs. An optimal pin fin shape and configuration is sought also taking manufacturing costs into consideration. Standard methods for geometrical modeling and thermal analysis are applied....

  18. Electronic states of myricetin

    DEFF Research Database (Denmark)

    Vojta, Danijela; Karlsen, Eva; Spanget-Larsen, Jens

    2017-01-01

    Myricetin (3,3',4',5,5',7'-hexahydroxyflavone) was investigated by linear dichroism spectroscopy on molecular samples partially aligned in stretched poly(vinyl alcohol) (PVA). At least five electronic transitions in the range 40000 – 20000 cm–1 were characterized with respect to their wavenumbers......, relative intensities, and transition moment directions. The observed bands were assigned to electronic transitions predicted with TD-B3LYP/6-31+G(d,p)....

  19. Newnes electronics assembly handbook

    CERN Document Server

    Brindley, Keith

    2013-01-01

    Newnes Electronics Assembly Handbook: Techniques, Standards and Quality Assurance focuses on the aspects of electronic assembling. The handbook first looks at the printed circuit board (PCB). Base materials, basic mechanical properties, cleaning of assemblies, design, and PCB manufacturing processes are then explained. The text also discusses surface mounted assemblies and packaging of electromechanical assemblies, as well as the soldering process. Requirements for the soldering process; solderability and protective coatings; cleaning of PCBs; and mass solder/component reflow soldering are des

  20. Electron Beam Ion Sources

    OpenAIRE

    Zschornacka, G.; Schmidt, M.; Thorn, A.

    2014-01-01

    Electron beam ion sources (EBISs) are ion sources that work based on the principle of electron impact ionization, allowing the production of very highly charged ions. The ions produced can be extracted as a DC ion beam as well as ion pulses of different time structures. In comparison to most of the other known ion sources, EBISs feature ion beams with very good beam emittances and a low energy spread. Furthermore, EBISs are excellent sources of photons (X-rays, ultraviolet, extreme ultraviole...

  1. 4D Electron Tomography

    OpenAIRE

    Kwon, Oh-Hoon; Zewail, Ahmed H.

    2010-01-01

    Electron tomography provides three-dimensional (3D) imaging of noncrystalline and crystalline equilibrium structures, as well as elemental volume composition, of materials and biological specimens, including those of viruses and cells. We report the development of 4D electron tomography by integrating the fourth dimension (time resolution) with the 3D spatial resolution obtained from a complete tilt series of 2D projections of an object. The different time frames of tomograms constitute a mov...

  2. Mathematics for electronic technology

    CERN Document Server

    Howson, D P

    1975-01-01

    Mathematics for Electronic Technology is a nine-chapter book that begins with the elucidation of the introductory concepts related to use of mathematics in electronic engineering, including differentiation, integration, partial differentiation, infinite series, vectors, vector algebra, and surface, volume and line integrals. Subsequent chapters explore the determinants, differential equations, matrix analysis, complex variable, topography, graph theory, and numerical analysis used in this field. The use of Fourier method for harmonic analysis and the Laplace transform is also described. The ma

  3. Electron scattering experiments

    Science.gov (United States)

    Heisenberg, J.

    1984-11-01

    Because of the elementary structure of the electron, it is considered a precise probe of the constituent nature of hadronic matter. Use of the electron as a probe of subnucleonic degrees of freedom in nuclei is discussed in this presentation. Experimentally determined charge distributions for a wide variety of nuclei are presented and compared with shell model calculations which include single particle modes, core polarization, corrections due to delta-hole components, and corrections due to inclusion of meson exchange currents. (AIP)

  4. Electronic Portfolios for Scientists

    OpenAIRE

    Dahn, I.; Christmann, A.

    2007-01-01

    Electronic portfolios (ePortfolios) are electronic versions of paper based portfolios. They are increasingly applied in education. Software for building and maintaining ePortfolios is emerging; open specifications for the exchange of ePortfolios exist. They show the potential to serve as a standard tool for documenting achievements in lifelong learning. In this paper we explore the potential of ePortfolios for scientists.

  5. Electrical and electronic principles

    CERN Document Server

    Knight, SA

    1988-01-01

    Electrical and Electronic Principles, 3 focuses on the principles involved in electrical and electronic circuits, including impedance, inductance, capacitance, and resistance.The book first deals with circuit elements and theorems, D.C. transients, and the series circuits of alternating current. Discussions focus on inductance and resistance in series, resistance and capacitance in series, power factor, impedance, circuit magnification, equation of charge, discharge of a capacitor, transfer of power, and decibels and attenuation. The manuscript then examines the parallel circuits of alternatin

  6. The Recycler Electron Cooler

    Energy Technology Data Exchange (ETDEWEB)

    Shemyakin, A. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Prost, L. R. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)

    2013-03-19

    The Recycler Electron cooler was the first (and so far, the only) cooler working at a relativistic energy (γ = 9.5). It was successfully developed in 1995-2004 and was in operation at Fermilab in 2005-2011, providing cooling of antiprotons in the Recycler ring. This paper describes the cooler, difficulties in achieving the required electron beam parameters and the ways to overcome them, cooling measurements, and details of operation.

  7. Trust in Consumer Electronics

    Science.gov (United States)

    Kursawe, Klaus; Katzenbeisser, Stefan

    While Trusted Computing is getting increasing attention in the PC world, consumer electronics devices have limited benefit from the Trusted Computing solutions currently under development. In this paper we outline the different requirements of consumer electronics devices, when compared to the PC world, and point out the technical consequences for standards like the Trusted Computing Group. In addition, we will touch on economic aspects that may inhibit or support Trusted Computing in this domain.

  8. Electron spectroscopy analysis

    Science.gov (United States)

    Gregory, John C.

    1992-01-01

    The Surface Science Laboratories at the University of Alabama in Huntsville (UAH) are equipped with x-ray photoelectron spectroscopy (XPS or ESCA) and Auger electron spectroscopy (AES) facilities. These techniques provide information from the uppermost atomic layers of a sample, and are thus truly surface sensitive. XPS provides both elemental and chemical state information without restriction on the type of material that can be analyzed. The sample is placed into an ultra high vacuum (UHV) chamber and irradiated with x-rays which cause the ejection of photoelectrons from the sample surface. Since x-rays do not normally cause charging problems or beam damage, XPS is applicable to a wide range of samples including metals, polymers, catalysts, and fibers. AES uses a beam of high energy electrons as a surface probe. Following electronic rearrangements within excited atoms by this probe, Auger electrons characteristic of each element present are emitted from the sample. The main advantage of electron induced AES is that the electron beam can be focused down to a small diameter and localized analysis can be carried out. On the rastering of this beam synchronously with a video display using established scanning electron microscopy techniques, physical images and chemical distribution maps of the surface can be produced. Thus very small features, such as electronic circuit elements or corrosion pits in metals, can be investigated. Facilities are available on both XPS and AES instruments for depth-profiling of materials, using a beam of argon ions to sputter away consecutive layers of material to reveal sub-surface (and even semi-bulk) analyses.

  9. Newnes electronics toolkit

    CERN Document Server

    Phillips, Geoff

    2013-01-01

    Newnes Electronics Toolkit brings together fundamental facts, concepts, and applications of electronic components and circuits, and presents them in a clear, concise, and unambiguous format, to provide a reference book for engineers. The book contains 10 chapters that discuss the following concepts: resistors, capacitors, inductors, semiconductors, circuit concepts, electromagnetic compatibility, sound, light, heat, and connections. The engineer's job does not end when the circuit diagram is completed; the design for the manufacturing process is just as important if volume production is to be

  10. Electronic states of myricetin

    DEFF Research Database (Denmark)

    Vojta, Danijela; Karlsen, Eva; Spanget-Larsen, Jens

    2016-01-01

    Myricetin (3,3',4',5,5',7'-hexahydroxyflavone) was investigated by linear dichroism spectroscopy on molecular samples partially aligned in stretched poly(vinyl alcohol) (PVA). At least five electronic transitions in the range 40000 – 20000 cm–1 were characterized with respect to their wavenumbers......, relative intensities, and transition moment directions. The observed bands were assigned to electronic transitions predicted with TD-B3LYP/6-31+G(d,p)....

  11. Electronics 3 checkbook

    CERN Document Server

    Knight, S A; May, A J C

    2013-01-01

    Electronics 3 Checkbook provides a concise coverage of the theories and definitions of concepts in electronics. The book provides problems and worked examples to supplement fuller textbooks of the same subject. The coverage of the text includes decibel measurement, operational amplifiers, DA and AD converters, controlled rectifiers, triggering devices, optoelectronic devices, fiber optics, and power amplifiers. The text will be of great use to electrical engineering students who wish to enhance their understanding of the basics of mechanical and electrical science.

  12. Electron Transfer Pathways in Cell

    OpenAIRE

    Yan Liu

    2012-01-01

    Analysis of the electron salvation process data indicates that the electron transfer between the electron donor and acceptor is hindered by the electron salvation process. It is proposed that the electron transfer in the cell environment must be assisted by intermediate messenger called the “transport protein”.

  13. Thermionics basic principles of electronics

    CERN Document Server

    Jenkins, J; Ashhurst, W

    2013-01-01

    Basic Principles of Electronics, Volume I : Thermionics serves as a textbook for students in physics. It focuses on thermionic devices. The book covers topics on electron dynamics, electron emission, and the themionic vacuum diode and triode. Power amplifiers, oscillators, and electronic measuring equipment are studied as well. The text will be of great use to physics and electronics students, and inventors.

  14. Netiquette in Electronic Communication

    Directory of Open Access Journals (Sweden)

    Tomáš Kozík

    2014-06-01

    Full Text Available Electronic mail and electronic communications systems are considered significant and effective tools of communication. One of the most widespread electronic communication tools is e - mail communication. In order to avoid misinterpretation of the report on the side of the recipient, it is need to pay attention to the writing of e - mail messages as well as to their content. With the continuous expansion of the use of electronic communication there have gradually developed certain rules of etiquette in electronic communications. The existing rules of the propriety ones are expressed in the term " etiqutte " and are not automatically applied in the new communications environment - media. For electronic communication, the new rules of etiquette have been stabilised into a term NETIQUETTE. The word netiquette was created by combining words NET (net and ETIKETA (a set of rules of social behavior and habits. Netiquette constitutes the rules of the behavior of users on a network. Although the netiquette is merely "an unwritten set of rules", their not using can be understood as a type of disrespect. Analysis of knowledge of domestic and foreign sources as well as results of a survey confirmed the justification of paying attention to the education of individuals in NETIQUETTE, irrespective of the degree of education.

  15. BOK-Printed Electronics

    Science.gov (United States)

    Ghaffarian, Reza

    2013-01-01

    The use of printed electronics technologies (PETs), 2D or 3D printing approaches either by conventional electronic fabrication or by rapid graphic printing of organic or nonorganic electronic devices on various small or large rigid or flexible substrates, is projected to grow exponentially in commercial industry. This has provided an opportunity to determine whether or not PETs could be applicable for low volume and high-reliability applications. This report presents a summary of literature surveyed and provides a body of knowledge (BOK) gathered on the current status of organic and printed electronics technologies. It reviews three key industry roadmaps- on this subject-OE-A, ITRS, and iNEMI-each with a different name identification for this emerging technology. This followed by a brief review of the status of the industry on standard development for this technology, including IEEE and IPC specifications. The report concludes with key technologies and applications and provides a technology hierarchy similar to those of conventional microelectronics for electronics packaging. Understanding key technology roadmaps, parameters, and applications is important when judicially selecting and narrowing the follow-up of new and emerging applicable technologies for evaluation, as well as the low risk insertion of organic, large area, and printed electronics.

  16. Good Security Practices for Electronic Commerce, Including Electronic Data Interchange

    Science.gov (United States)

    1993-12-01

    FROM - TO) xx-xx-2002 to xx-xx-2002 4. TITLE AND SUBTITLE Good Security Practices for Electronic Commerce , Including Electronic Data Interchange...Report 12/1/1993 4. TITLE AND SUBTITLE Good Security Practices for Electronic Commerce , Including Electronic Data Interchange 5. FUNDING NUMBERS 6...Maximum 200 Words) Electronic commerce (EC) is the use of documents in electronic form, rather than paper, for carrying out functions of business or

  17. Electron holes in inhomogeneous magnetic field: electron heating and electron hole evolution

    Science.gov (United States)

    Vasko, Ivan; Agapitov, Oleksiy; Mozer, Forrest; Artemyev, Anton; Drake, James

    2016-04-01

    Electron holes are electrostatic non-linear structures widely observed in the space plasma, e.g., in reconnecting current sheets, collisionless bow shocks, Earth auroral region and outer radiation belt etc. In the present paper we analyze the process of energy exchange between trapped electrons, untrapped electrons and electron hole propagating in weakly inhomogeneous magnetic field. We show that as electron hole propagates into the region with stronger magnetic field, trapped electrons are heated due to conservation of the first adiabatic invariant. At the same time electron hole may grow or dissipate in dependence on peculiarities of distribution functions of trapped and resonant untrapped electrons. The energy gain of trapped electrons is due to energy losses of resonant electrons and/or decrease of electron hole energy (electrostatic energy and kinetic energy of non-resonant electrons). We stress that taking into account the energy exchange with resonant untrapped electrons increases the heating factor of trapped electrons that is proportional to the magnetic field magnitude in the region up to what electron holes survive. We illustrate the suggested mechanism for H. Schamel's electron holes and show that during propagation along a positive magnetic field gradient their amplitude should grow. Neglect of energy exchange with resonant untrapped electrons would result electron hole dissipation with only modest heating factor of trapped electrons. We argue that the suggested mechanism may be responsible for generation of energetic electrons in the space plasma.

  18. Runaway electrons and ITER

    Science.gov (United States)

    Boozer, Allen H.

    2017-05-01

    The potential for damage, the magnitude of the extrapolation, and the importance of the atypical—incidents that occur once in a thousand shots—make theory and simulation essential for ensuring that relativistic runaway electrons will not prevent ITER from achieving its mission. Most of the theoretical literature on electron runaway assumes magnetic surfaces exist. ITER planning for the avoidance of halo and runaway currents is focused on massive-gas or shattered-pellet injection of impurities. In simulations of experiments, such injections lead to a rapid large-scale magnetic-surface breakup. Surface breakup, which is a magnetic reconnection, can occur on a quasi-ideal Alfvénic time scale when the resistance is sufficiently small. Nevertheless, the removal of the bulk of the poloidal flux, as in halo-current mitigation, is on a resistive time scale. The acceleration of electrons to relativistic energies requires the confinement of some tubes of magnetic flux within the plasma and a resistive time scale. The interpretation of experiments on existing tokamaks and their extrapolation to ITER should carefully distinguish confined versus unconfined magnetic field lines and quasi-ideal versus resistive evolution. The separation of quasi-ideal from resistive evolution is extremely challenging numerically, but is greatly simplified by constraints of Maxwell’s equations, and in particular those associated with magnetic helicity. The physics of electron runaway along confined magnetic field lines is clarified by relations among the poloidal flux change required for an e-fold in the number of electrons, the energy distribution of the relativistic electrons, and the number of relativistic electron strikes that can be expected in a single disruption event.

  19. Beginning analog electronics through projects

    CERN Document Server

    Singmin, Andrew

    2001-01-01

    Analog electronics is the simplest way to start a fun, informative, learning program. Beginning Analog Electronics Through Projects, Second Edition was written with the needs of beginning hobbyists and students in mind. This revision of Andrew Singmin's popular Beginning Electronics Through Projects provides practical exercises, building techniques, and ideas for useful electronics projects. Additionally, it features new material on analog and digital electronics, and new projects for troubleshooting test equipment.Published in the tradition of Beginning Electronics Through Projects an

  20. Cooling system for electronic components

    Energy Technology Data Exchange (ETDEWEB)

    Anderl, William James; Colgan, Evan George; Gerken, James Dorance; Marroquin, Christopher Michael; Tian, Shurong

    2016-05-17

    Embodiments of the present invention provide for non interruptive fluid cooling of an electronic enclosure. One or more electronic component packages may be removable from a circuit card having a fluid flow system. When installed, the electronic component packages are coincident to and in a thermal relationship with the fluid flow system. If a particular electronic component package becomes non-functional, it may be removed from the electronic enclosure without affecting either the fluid flow system or other neighboring electronic component packages.

  1. Cooling system for electronic components

    Energy Technology Data Exchange (ETDEWEB)

    Anderl, William James; Colgan, Evan George; Gerken, James Dorance; Marroquin, Christopher Michael; Tian, Shurong

    2015-12-15

    Embodiments of the present invention provide for non interruptive fluid cooling of an electronic enclosure. One or more electronic component packages may be removable from a circuit card having a fluid flow system. When installed, the electronic component packages are coincident to and in a thermal relationship with the fluid flow system. If a particular electronic component package becomes non-functional, it may be removed from the electronic enclosure without affecting either the fluid flow system or other neighboring electronic component packages.

  2. Microfluidic stretchable RF electronics.

    Science.gov (United States)

    Cheng, Shi; Wu, Zhigang

    2010-12-07

    Stretchable electronics is a revolutionary technology that will potentially create a world of radically different electronic devices and systems that open up an entirely new spectrum of possibilities. This article proposes a microfluidic based solution for stretchable radio frequency (RF) electronics, using hybrid integration of active circuits assembled on flex foils and liquid alloy passive structures embedded in elastic substrates, e.g. polydimethylsiloxane (PDMS). This concept was employed to implement a 900 MHz stretchable RF radiation sensor, consisting of a large area elastic antenna and a cluster of conventional rigid components for RF power detection. The integrated radiation sensor except the power supply was fully embedded in a thin elastomeric substrate. Good electrical performance of the standalone stretchable antenna as well as the RF power detection sub-module was verified by experiments. The sensor successfully detected the RF radiation over 5 m distance in the system demonstration. Experiments on two-dimensional (2D) stretching up to 15%, folding and twisting of the demonstrated sensor were also carried out. Despite the integrated device was severely deformed, no failure in RF radiation sensing was observed in the tests. This technique illuminates a promising route of realizing stretchable and foldable large area integrated RF electronics that are of great interest to a variety of applications like wearable computing, health monitoring, medical diagnostics, and curvilinear electronics.

  3. Electron microscope phase enhancement

    Science.gov (United States)

    Jin, Jian; Glaeser, Robert M.

    2010-06-15

    A microfabricated electron phase shift element is used for modifying the phase characteristics of an electron beam passing though its center aperture, while not affecting the more divergent portion of an incident beam to selectively provide a ninety-degree phase shift to the unscattered beam in the back focal plan of the objective lens, in order to realize Zernike-type, in-focus phase contrast in an electron microscope. One application of the element is to increase the contrast of an electron microscope for viewing weakly scattering samples while in focus. Typical weakly scattering samples include biological samples such as macromolecules, or perhaps cells. Preliminary experimental images demonstrate that these devices do apply a ninety degree phase shift as expected. Electrostatic calculations have been used to determine that fringing fields in the region of the scattered electron beams will cause a negligible phase shift as long as the ratio of electrode length to the transverse feature-size aperture is about 5:1. Calculations are underway to determine the feasibility of aspect smaller aspect ratios of about 3:1 and about 2:1.

  4. Electronic Spectroscopy & Dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Mark Maroncelli, Nancy Ryan Gray

    2010-06-08

    The Gordon Research Conference (GRC) on Electronic Spectroscopy and Dynamics was held at Colby College, Waterville, NH from 07/19/2009 thru 07/24/2009. The Conference was well-attended with participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. The GRC on Electronic Spectroscopy & Dynamics showcases some of the most recent experimental and theoretical developments in electronic spectroscopy that probes the structure and dynamics of isolated molecules, molecules embedded in clusters and condensed phases, and bulk materials. Electronic spectroscopy is an important tool in many fields of research, and this GRC brings together experts having diverse backgrounds in physics, chemistry, biophysics, and materials science, making the meeting an excellent opportunity for the interdisciplinary exchange of ideas and techniques. Topics covered in this GRC include high-resolution spectroscopy, biological molecules in the gas phase, electronic structure theory for excited states, multi-chromophore and single-molecule spectroscopies, and excited state dynamics in chemical and biological systems.

  5. Reversibly Bistable Flexible Electronics

    KAUST Repository

    Alfaraj, Nasir

    2015-05-01

    Introducing the notion of transformational silicon electronics has paved the way for integrating various applications with silicon-based, modern, high-performance electronic circuits that are mechanically flexible and optically semitransparent. While maintaining large-scale production and prototyping rapidity, this flexible and translucent scheme demonstrates the potential to transform conventionally stiff electronic devices into thin and foldable ones without compromising long-term performance and reliability. In this work, we report on the fabrication and characterization of reversibly bistable flexible electronic switches that utilize flexible n-channel metal-oxide-semiconductor field-effect transistors. The transistors are fabricated initially on rigid (100) silicon substrates before they are peeled off. They can be used to control flexible batches of light-emitting diodes, demonstrating both the relative ease of scaling at minimum cost and maximum reliability and the feasibility of integration. The peeled-off silicon fabric is about 25 µm thick. The fabricated devices are transferred to a reversibly bistable flexible platform through which, for example, a flexible smartphone can be wrapped around a user’s wrist and can also be set back to its original mechanical position. Buckling and cyclic bending of such host platforms brings a completely new dimension to the development of flexible electronics, especially rollable displays.

  6. Electronic Commerce user manual

    Energy Technology Data Exchange (ETDEWEB)

    1992-04-10

    This User Manual supports the Electronic Commerce Standard System. The Electronic Commerce Standard System is being developed for the Department of Defense of the Technology Information Systems Program at the Lawrence Livermore National Laboratory, operated by the University of California for the Department of Energy. The Electronic Commerce Standard System, or EC as it is known, provides the capability for organizations to conduct business electronically instead of through paper transactions. Electronic Commerce and Computer Aided Acquisition and Logistics Support, are two major projects under the DoD`s Corporate Information Management program, whose objective is to make DoD business transactions faster and less costly by using computer networks instead of paper forms and postage. EC runs on computers that use the UNIX operating system and provides a standard set of applications and tools that are bound together by a common command and menu system. These applications and tools may vary according to the requirements of the customer or location and may be customized to meet the specific needs of an organization. Local applications can be integrated into the menu system under the Special Databases & Applications option on the EC main menu. These local applications will be documented in the appendices of this manual. This integration capability provides users with a common environment of standard and customized applications.

  7. Electronic Commerce user manual

    Energy Technology Data Exchange (ETDEWEB)

    1992-04-10

    This User Manual supports the Electronic Commerce Standard System. The Electronic Commerce Standard System is being developed for the Department of Defense of the Technology Information Systems Program at the Lawrence Livermore National Laboratory, operated by the University of California for the Department of Energy. The Electronic Commerce Standard System, or EC as it is known, provides the capability for organizations to conduct business electronically instead of through paper transactions. Electronic Commerce and Computer Aided Acquisition and Logistics Support, are two major projects under the DoD's Corporate Information Management program, whose objective is to make DoD business transactions faster and less costly by using computer networks instead of paper forms and postage. EC runs on computers that use the UNIX operating system and provides a standard set of applications and tools that are bound together by a common command and menu system. These applications and tools may vary according to the requirements of the customer or location and may be customized to meet the specific needs of an organization. Local applications can be integrated into the menu system under the Special Databases Applications option on the EC main menu. These local applications will be documented in the appendices of this manual. This integration capability provides users with a common environment of standard and customized applications.

  8. Pulsed electron beam precharger

    Energy Technology Data Exchange (ETDEWEB)

    Finney, W.C. (ed.); Shelton, W.N.

    1990-01-01

    Electrostatic collection of a high resistivity aerosol using the Electron Beam Precipitator (EBP) collecting section was demonstrated during this reporting period (Quarter Five). Collection efficiency experiments were designed to confirm and extend some of the work performed under the previous contract. The reason for doing this was to attempt to improve upon the collection efficiency of the precipitator alone when testing with a very high resistivity, moderate-to-high concentration dust load. From the collector shakedown runs, a set of suitable operational parameters were determined for the downstream electrostatic collecting sections of the Electron Beam Precipitator wind tunnel. These parameters, along with those for the MINACC electron beam, will generally be held constant while the numerous precharging parameters are varied to produce an optimum particle charge. The electrostatic collector experiments were part of a larger, comprehensive investigation on electron beam precharging of high resistivity aerosol particles performed during the period covered by Quarters Five, Six, and Seven. This body of work used the same experimental apparatus and procedures and the experimental run period lasted nearly continuously for six months. A summary of the Quarter Five work is presented in the following paragraphs. Section II-A of TPR 5 contains a report on the continuing effort which was expended on the modification and upgrade of the pulsed power supply and the monitoring systems prior to the initiation of the electron beam precharging experimental work.

  9. Electron correlation in beryllium

    DEFF Research Database (Denmark)

    Omiste, Juan J.; Li, Wenliang; Madsen, Lars Bojer

    2017-01-01

    We apply a three-dimensional implementation of the time-dependent restricted-active-space self-consistent-field (TD-RASSCF) method to investigate effects of electron correlation in the ground state of Be as well as in its photoionization dynamics by short XUV pulses, including time delay in photo......We apply a three-dimensional implementation of the time-dependent restricted-active-space self-consistent-field (TD-RASSCF) method to investigate effects of electron correlation in the ground state of Be as well as in its photoionization dynamics by short XUV pulses, including time delay...... schemes, and in this way we identify the orbital spaces that are relevant for an accurate description of the photoelectron spectra. Finally, we investigate the effects of electron correlation on the magnitude of the relative Eisenbud-Wigner-Smith (EWS) time delay in the photoionization process into two...... different ionic channels. One channel, the ground-state channel in the ion, is accessible without electron correlation. The other channel is only accessible when including electron correlation. For theory beyond the mean-field time-dependent Hartree-Fock, the EWS time delay for the photon energy analyzed...

  10. Electronic Submissions of Pesticide Applications

    Science.gov (United States)

    Applications for pesticide registration can be submitted electronically, including forms, studies, and draft product labeling. Applicants need not submit multiple electronic copies of any pieces of their applications.

  11. Phasor power electronics

    CERN Document Server

    Rim, Chun T

    2016-01-01

    This book presents a comprehensive introduction to the principles of power electronics, focusing on the switched transformer concept and phasor transformation techniques as employed in the analysis and design of power electronic circuits. Phasor transformations, as introduced in this book, make the time-varying nature of a switching converter simple and easy to handle, transforming it into an equivalent time-invariant circuit. The book starts with an introduction to the philosophy and fundamental principles of power electronics. The switched transformer concept, which is applicable to any switching converter, is introduced, and it is shown how DC-DC converters analyses are then so straightforward that very little equational manipulation is needed. Then the phasor transformation techniques are comprehensively explained over three parts. Single phase and multi-phase AC systems are dealt with through the single phase phasor transformation and circuit DQ transformation, respectively. A general unified phasor tran...

  12. Understanding the Electron

    CERN Document Server

    Knuth, Kevin H

    2015-01-01

    Well over a century after the discovery of the electron, we are still faced with serious conceptual issues regarding precisely what an electron is. Since the development of particle physics and the Standard Model, we have accumulated a great deal of knowledge about the relationships among various subatomic particles. However, this knowledge has not significantly aided in our understanding of the fundamental nature of any particular elementary subatomic particle. The fact that many particle properties, such as position, time, speed, energy, momentum, and component of spin, are observer-dependent suggests that these relevant variables do not represent properties per se, but rather the relationship between the observer and the observed. That is, they reflect details about how the electron influences the observer, and vice versa. Here we attempt to understand this by considering a simple model where particles influence one another in a discrete and direct fashion. The resulting framework, referred to as Influence...

  13. On Zitterbewegung of Electron

    Institute of Scientific and Technical Information of China (English)

    WANG Zhi-yong; XIONG Cai-dong; ZHOU Ping

    2005-01-01

    Traditionally, all the discussions on zitterbewegung (zbw) of electron are based on relativistic quantum mechanics. In this article, from the viewpoint of quantum field theory and in terms of the creation and annihilation operators as well as the polarization vectors of spin-1 field, a more detailed description and some new perspectives for zbw are obtained. Especially, it is shown that zbw arises from a to-and-fro vacuum polarization that occurring in the neighborhood of electron; the zbw vectors form a vector triplet with total spin projections 0 and ±1 in the direction of the momentum of electron, respectively; the macroscopic velocity of the vacuum medium vanishes in all inertial systems.

  14. Electronic apex locators.

    Science.gov (United States)

    Gordon, M P J; Chandler, N P

    2004-07-01

    Prior to root canal treatment at least one undistorted radiograph is required to assess canal morphology. The apical extent of instrumentation and the final root filling have a role in treatment success, and are primarily determined radiographically. Electronic apex locators reduce the number of radiographs required and assist where radiographic methods create difficulty. They may also indicate cases where the apical foramen is some distance from the radiographic apex. Other roles include the detection of root canal perforation. A review of the literature focussed first on the subject of electronic apex location. A second review used the names of apex location devices. From the combined searches, 113 pertinent articles in English were found. This paper reviews the development, action, use and types of electronic apex locators.

  15. Electron Technology: ELTE 2016

    Science.gov (United States)

    Pisarkiewicz, Tadeusz; Kucewicz, Wojciech

    2016-12-01

    In this paper we present a review of research results and technical accomplishments presented by researchers from technical universities, governmental institutes and research companies during the XIIth Scientific Conference Electron Technology, ELTE 2016. This review is based on materials presented at four topical conference sessions: Microelectronics and Nanoelectronics, Photonics, Materials and Technologies, and Microsystems and also on materials presented by invited speakers at two dedicated sessions. Oral sessions were accompanied by the poster sessions. In effect about 50 papers gathered in this volume reflect the topics discussed at the Conference. A short description of technological and measurement possibilities in the laboratories of Academic Centre for Materials and Nanotechnology and also in the Department of Electronics of the Faculty of Computer Science, Electronics and Telecommunications AGH UST are given.

  16. Microelectronics improves power electronics

    Energy Technology Data Exchange (ETDEWEB)

    Diehl, R.

    1982-07-01

    The share of electric energy consumed by electric drives - called power current - can be used more efficiently by using power electronic regulating processes. Lower cost for power electronic components and progress in circuit technology are the decisive factors for the widespread use of regulating units. Microelectronics permit a cost-beneficial control of power regulating units, are made them more attractive for the user. Technical and economic attractivity of power electronic regulating processes have increased. These processes are mainly used for adjusting engine speed to the other process engineering parameters like pressure, output or speed. Optimization of power-current consuming processes are expected to achieve an energy saving potential of 15 TWh by the year 1995.

  17. 4D Electron Tomography

    Science.gov (United States)

    Kwon, Oh-Hoon; Zewail, Ahmed H.

    2010-06-01

    Electron tomography provides three-dimensional (3D) imaging of noncrystalline and crystalline equilibrium structures, as well as elemental volume composition, of materials and biological specimens, including those of viruses and cells. We report the development of 4D electron tomography by integrating the fourth dimension (time resolution) with the 3D spatial resolution obtained from a complete tilt series of 2D projections of an object. The different time frames of tomograms constitute a movie of the object in motion, thus enabling studies of nonequilibrium structures and transient processes. The method was demonstrated using carbon nanotubes of a bracelet-like ring structure for which 4D tomograms display different modes of motion, such as breathing and wiggling, with resonance frequencies up to 30 megahertz. Applications can now make use of the full space-time range with the nanometer-femtosecond resolution of ultrafast electron tomography.

  18. Electronic network links physicists

    Science.gov (United States)

    Now that AGU is a member of the American Institute of Physics (AIP) (see item on page 150), AGU members may access Pi-NET, the Physics Information Network developed by AIP on behalf of its member societies. The electronic network will be available after March 31, 1986, to members of AIP member and affiliate societies for the cost of a local telephone call.This electronic database service provides listings of job opportunities in physics, calendars of meetings, advance abstracts of more than 40 journals published by AIP and member societies, brief announcements and news items, titles of journal articles from AIP's Searchable Physics Information Notices (SPIN) database, and an electronic catalog and on-line ordering of publications from AIP and member societies. AGU journals will be included in the database shortly.

  19. Laser assisted electron dynamics

    CERN Document Server

    Bray, Alexander William

    2016-01-01

    We apply the convergent close-coupling (CCC) formalism to analyse the processes of laser assisted electron impact ionisation of He, and the attosecond time delay in the photodetachment of the H^{-} ion and the photoionisation of He. Such time dependent atomic collision processes are of considerable interest as experimental measurements on the relevant timescale (attoseconds 10^{-18} s) are now possible utilising ultrafast and intense laser pulses. These processes in particular are furthermore of interest as they are strongly influenced by many-electron correlations. In such cases their theoretical description requires a more comprehensive treatment than that offered by first order perturbation theory. We apply such a treatment through the use of the CCC formalism which involves the complete numeric solution of the integral Lippmann-Schwinger equations pertaining to a particular scattering event. For laser assisted electron impact ionisation of He such a treatment is of a considerably greater accuracy than the...

  20. Relativistic Runaway Electrons

    Science.gov (United States)

    Breizman, Boris

    2014-10-01

    This talk covers recent developments in the theory of runaway electrons in a tokamak with an emphasis on highly relativistic electrons produced via the avalanche mechanism. The rapidly growing population of runaway electrons can quickly replace a large part of the initial current carried by the bulk plasma electrons. The magnetic energy associated with this current is typically much greater than the particle kinetic energy. The current of a highly relativistic runaway beam is insensitive to the particle energy, which separates the description of the runaway current evolution from the description of the runaway energy spectrum. A strongly anisotropic distribution of fast electrons is generally prone to high-frequency kinetic instabilities that may cause beneficial enhancement of runaway energy losses. The relevant instabilities are in the frequency range of whistler waves and electron plasma waves. The instability thresholds reported in earlier work have been revised considerably to reflect strong dependence of collisional damping on the wave frequency and the role of plasma non-uniformity, including radial trapping of the excited waves in the plasma. The talk also includes a discussion of enhanced scattering of the runaways as well as the combined effect of enhanced scattering and synchrotron radiation. A noteworthy feature of the avalanche-produced runaway current is a self-sustained regime of marginal criticality: the inductive electric field has to be close to its critical value (representing avalanche threshold) at every location where the runaway current density is finite, and the current density should vanish at any point where the electric field drops below its critical value. This nonlinear Ohm's law enables complete description of the evolving current profile. Work supported by the U.S. Department of Energy Contract No. DEFG02-04ER54742 and by ITER contract ITER-CT-12-4300000273. The views and opinions expressed herein do not necessarily reflect those of

  1. Electron-electron correlations in liquid s-p metals

    CERN Document Server

    Leys, F E

    2003-01-01

    We present calculations for the valence electron-electron structure factor in liquid Mg near freezing, assuming knowledge of the jellium result. On the basis of this, we predict significant corrections to jellium short-range correlations in liquid s-p metals and in particular an increase in the electron-electron contact probability.

  2. Electron kinetics in capacitively coupled plasmas modulated by electron injection

    Science.gov (United States)

    Zhang, Ya; Peng, Yanli; Innocenti, Maria Elena; Jiang, Wei; Wang, Hong-yu; Lapenta, Giovanni

    2017-09-01

    The controlling effect of an electron injection on the electron energy distribution function (EEDF) and on the energetic electron flux, in a capacitive radio-frequency argon plasma, is studied using a one-dimensional particle-in-cell/Monte Carlo collisions model. The input power of the electron beam is as small as several tens of Watts with laboratory achievable emission currents and energies. With the electron injection, the electron temperature decreases but with a significant high energy tail. The electron density, electron temperature in the sheath, and electron heating rate increase with the increasing emission energy. This is attributed to the extra heating of the energetic electrons in the EEDF tail. The non-equilibrium EEDF is obtained for strong non-local distributions of the electric field, electron heating rate, excitation, and ionization rate, indicating the discharge has transited from a volume heating (α-mode dominated) into a sheath heating (γ-mode dominated) type. In addition, the electron injection not only modifies the self-bias voltage, but also enhances the electron flux that can reach the electrodes. Moreover, the relative population of energetic electrons significantly increases with the electron injection compared to that without the electron injection, relevant for modifying the gas and surface chemistry reactions.

  3. Advances in quantum electronics

    CERN Document Server

    Goodwin, D W

    1974-01-01

    Advances in Quantum Electronics, Volume 2 deals with the effects of quantum mechanics on the behavior of electrons in matter. This book is divided into three chapters. Chapter 1 reviews the statistical properties of optical fields and spectral processing techniques, including the use of photon correlation techniques to measure scattering effects in a number of different media. The use of optical E.P.R. and excitation spectroscopic techniques and techniques for establishing the location of impurity ions in the chalcogenides are describe in Chapter 2. The last chapter surveys the field of mode l

  4. Recycling of electronic scrap

    DEFF Research Database (Denmark)

    Legarth, Jens Brøbech

    This Ph.D. thesis deals with the growingly important field of electronics recycling with special attention to the problem of printed circuit board recycling. A literature survey of contemporary electronics recycling and printed circuit board recycling is presented.Further, an analysis of the role...... in the metals producing industry is presented and tested on two printed circuit board scrap cases. The underlying idea for the method is that complex scrap should be introduced in the matrix of man-made material flows at recipient points where the scrap constitutes the least environmental problem and where...

  5. Advances in electronic materials

    CERN Document Server

    Kasper, Erich; Grimmeiss, Hermann G

    2008-01-01

    This special-topic volume, Advances in Electronic Materials, covers various fields of materials research such as silicon, silicon-germanium hetero-structures, high-k materials, III-V semiconductor alloys and organic materials, as well as nano-structures for spintronics and photovoltaics. It begins with a brief summary of the formative years of microelectronics; now the keystone of information technology. The latter remains one of the most important global technologies, and is an extremely complex subject-area. Although electronic materials are primarily associated with computers, the internet

  6. Electronically configured battery pack

    Energy Technology Data Exchange (ETDEWEB)

    Kemper, D.

    1997-03-01

    Battery packs for portable equipment must sometimes accommodate conflicting requirements to meet application needs. An electronically configurable battery pack was developed to support two highly different operating modes, one requiring very low power consumption at a low voltage and the other requiring high power consumption at a higher voltage. The configurable battery pack optimizes the lifetime and performance of the system by making the best use of all available energy thus enabling the system to meet its goals of operation, volume, and lifetime. This paper describes the cell chemistry chosen, the battery pack electronics, and tradeoffs made during the evolution of its design.

  7. Conventional transmission electron microscopy.

    Science.gov (United States)

    Winey, Mark; Meehl, Janet B; O'Toole, Eileen T; Giddings, Thomas H

    2014-02-01

    Researchers have used transmission electron microscopy (TEM) to make contributions to cell biology for well over 50 years, and TEM continues to be an important technology in our field. We briefly present for the neophyte the components of a TEM-based study, beginning with sample preparation through imaging of the samples. We point out the limitations of TEM and issues to be considered during experimental design. Advanced electron microscopy techniques are listed as well. Finally, we point potential new users of TEM to resources to help launch their project.

  8. Electronics for technicians

    CERN Document Server

    Crane, P W

    2013-01-01

    Electronics for Technicians covers the basic fundamentals of electronics, including the operation of devices and circuits. The book is meant to help the technician to obtain numerical answers to actual circuit problems. This volume consists of seven chapters, the first of which introduces the reader to the basic rules for circuits containing resistive and reactive elements. Charge and discharge of a capacitor through a resistor is discussed, along with charge and discharge of an inductance through a resistance, application of sinusoidal voltages to simple networks, and series and parallel LCR

  9. Precision electron polarimetry

    Energy Technology Data Exchange (ETDEWEB)

    Chudakov, E. [Jefferson Lab 12000 Jefferson Ave, STE 16, Newport News, VA 23606 (United States)

    2013-11-07

    A new generation of precise Parity-Violating experiments will require a sub-percent accuracy of electron beam polarimetry. Compton polarimetry can provide such accuracy at high energies, but at a few hundred MeV the small analyzing power limits the sensitivity. Mo/ller polarimetry provides a high analyzing power independent on the beam energy, but is limited by the properties of the polarized targets commonly used. Options for precision polarimetry at 300 MeV will be discussed, in particular a proposal to use ultra-cold atomic hydrogen traps to provide a 100%-polarized electron target for Mo/ller polarimetry.

  10. Pulsed Electron Holography

    CERN Document Server

    Germann, Matthias; Escher, Conrad; Fink, Hans-Werner

    2013-01-01

    A technique of pulsed low-energy electron holography is introduced that allows for recording highly resolved holograms within reduced exposure times. Therefore, stacks of holograms are accumulated in a pulsed mode with individual acquisition times as short as 50 {\\mu}s. Subsequently, these holograms are aligned and finally superimposed. The resulting holographic record reveals previously latent high-order interference fringes and thereby pushing interference resolution into the sub-nanometer regime. In view of the non-damaging character of low-energy electrons, the method is of particular interest for structural analysis of fragile biomolecules.

  11. Electronics 2 checkbook

    CERN Document Server

    Knight, S A

    2013-01-01

    Electronics 2 Checkbook is an 11-chapter text that presents problems and worked examples to establish and exemplify the theory contained in technical syllabuses, with a particular emphasis on electronics.The introductory chapters review the elementary theory of semiconductors and the p-n junction diode. The subsequent chapters deal with the applications of diode, the characteristics of bipolar transistors, and the mode of operation of small signal amplifiers. These topics are followed by discussions of the function of the field-effect transistor and power supplies. The concluding chapters expl

  12. VLSI electronics microstructure science

    CERN Document Server

    1981-01-01

    VLSI Electronics: Microstructure Science, Volume 3 evaluates trends for the future of very large scale integration (VLSI) electronics and the scientific base that supports its development.This book discusses the impact of VLSI on computer architectures; VLSI design and design aid requirements; and design, fabrication, and performance of CCD imagers. The approaches, potential, and progress of ultra-high-speed GaAs VLSI; computer modeling of MOSFETs; and numerical physics of micron-length and submicron-length semiconductor devices are also elaborated. This text likewise covers the optical linewi

  13. Electronic Word of Behavior

    DEFF Research Database (Denmark)

    Kunst, Katrine

    It is widely recognized that the transition from Word-of-mouth (WOM) to electronic word-of-mouth (eWOM) allows for a wider and faster spread of information. However, little attention has been given to how digital channels expand the types of information consumers share. In this paper, we argue...... of the concepts do not capture this new kind of consumer-to-consumer information transfer about products and services. Consequently, we suggest an extension of those concepts: Electronic Word of Behavior....

  14. Modern electronic maintenance principles

    CERN Document Server

    Garland, DJ

    2013-01-01

    Modern Electronic Maintenance Principles reviews the principles of maintaining modern, complex electronic equipment, with emphasis on preventive and corrective maintenance. Unfamiliar subjects such as the half-split method of fault location, functional diagrams, and fault finding guides are explained. This book consists of 12 chapters and begins by stressing the need for maintenance principles and discussing the problem of complexity as well as the requirements for a maintenance technician. The next chapter deals with the connection between reliability and maintenance and defines the terms fai

  15. Practical electronics handbook

    CERN Document Server

    Sinclair, Ian R

    1988-01-01

    Practical Electronics Handbook, Second Edition covers information useful in electronics, with focus on mathematical conventions. The handbook discusses the passive (resistors, capacitors, band coding, and inductors) and active discrete (diodes, transistors and negative feedback) components; discrete component circuits; and transferring digital data. Linear I.C.s, which are the single-chip arrangements of amplifier circuits that are intended to be biased and operated in a linear way, and digital I.C.s, which process signals and consist of two significant voltage levels, are also considered. T

  16. Gallium nitride electronics

    Science.gov (United States)

    Rajan, Siddharth; Jena, Debdeep

    2013-07-01

    In the past two decades, there has been increasing research and industrial activity in the area of gallium nitride (GaN) electronics, stimulated first by the successful demonstration of GaN LEDs. While the promise of wide band gap semiconductors for power electronics was recognized many years before this by one of the contributors to this issue (J Baliga), the success in the area of LEDs acted as a catalyst. It set the field of GaN electronics in motion, and today the technology is improving the performance of several applications including RF cell phone base stations and military radar. GaN could also play a very important role in reducing worldwide energy consumption by enabling high efficiency compact power converters operating at high voltages and lower frequencies. While GaN electronics is a rapidly evolving area with active research worldwide, this special issue provides an opportunity to capture some of the great advances that have been made in the last 15 years. The issue begins with a section on epitaxy and processing, followed by an overview of high-frequency HEMTs, which have been the most commercially successful application of III-nitride electronics to date. This is followed by review and research articles on power-switching transistors, which are currently of great interest to the III-nitride community. A section of this issue is devoted to the reliability of III-nitride devices, an area that is of increasing significance as the research focus has moved from not just high performance but also production-worthiness and long-term usage of these devices. Finally, a group of papers on new and relatively less studied ideas for III-nitride electronics, such as interband tunneling, heterojunction bipolar transistors, and high-temperature electronics is included. These areas point to new areas of research and technological innovation going beyond the state of the art into the future. We hope that the breadth and quality of articles in this issue will make it

  17. Electronics made simple

    CERN Document Server

    Olsen, George H

    1987-01-01

    Electronics: Made Simple covers the fundamental principles, basic devices, characteristics, and application of electronic equipment.This book is divided into 15 chapters and begins with reviews of the properties and behavior of resistors, capacitors, inductors, and semiconductor devices. Considerable chapters deal with how these devices can be assembled into useful fundamental circuits such as amplifiers, oscillators and power supplies. These topics are followed by discussions of the importance of integrated circuits and the use of digital equipment and photocells in control and computing appa

  18. Electronic components and technology

    CERN Document Server

    Sangwine, Stephen

    2007-01-01

    Most introductory textbooks in electronics focus on the theory while leaving the practical aspects to be covered in laboratory courses. However, the sooner such matters are introduced, the better able students will be to include such important concerns as parasitic effects and reliability at the very earliest stages of design. This philosophy has kept Electronic Components and Technology thriving for two decades, and this completely updated third edition continues the approach with a more international outlook.Not only does this textbook introduce the properties, behavior, fabrication, and use

  19. Nanotube electronics and optoelectronics

    Directory of Open Access Journals (Sweden)

    Phaedon Avouris

    2006-10-01

    Full Text Available Among the many materials that have been proposed to supplement and, in the long run, possibly succeed Si as a basis for nanoelectronics, carbon nanotubes (CNTs have attracted the most attention. CNTs are quasi-one-dimensional materials with unique properties ideally suited for electronics. We briefly discuss the electrical and optical properties of CNTs and how they can be employed in electronics and optoelectronics. We focus on single CNT transistors, their fabrication, assembly, doping, electrical characteristics, and integration. We also address the possible use of CNTs in optoelectronic devices such as electroluminescent light emitters and photodetectors.

  20. Relativistic electronic dressing

    CERN Document Server

    Attaourti, Y

    2002-01-01

    We study the effects of the relativistic electronic dressing in laser-assisted electron-hydrogen atom elastic collisions. We begin by considering the case when no radiation is present. This is necessary in order to check the consistency of our calculations and we then carry out the calculations using the relativistic Dirac-Volkov states. It turns out that a simple formal analogy links the analytical expressions of the differential cross section without laser and the differential cross section in presence of a laser field.

  1. Diagnostic electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Dickersin, G.R.

    1988-01-01

    In this book the author presents a comprehensive reference text on diagnostic electron microscopy. Throughout the book he illustrates how ultrastructural identification can be helpful for the recognition of cell type and the identification of mechanisms of pathogenesis in various diseases. In addition to electron microscopy photographs, there are also numerous light microscopy photographs for comparison. This text presents the classification of neoplasms in the order and arrangement most familiar to the pathologist. Contents: Introduction; Diagram of a Normal Cell; Normal Cell Function; Embryology; Neoplasms; Infectious Agents; Metabolic Diseases; Renal Diseases; Skeletal Muscle and Peripheral Nerve Diseases; Index.

  2. Electronic logic circuits

    CERN Document Server

    Gibson, J

    2013-01-01

    Most branches of organizing utilize digital electronic systems. This book introduces the design of such systems using basic logic elements as the components. The material is presented in a straightforward manner suitable for students of electronic engineering and computer science. The book is also of use to engineers in related disciplines who require a clear introduction to logic circuits. This third edition has been revised to encompass the most recent advances in technology as well as the latest trends in components and notation. It includes a wide coverage of application specific integrate

  3. Precision electron polarimetry

    Energy Technology Data Exchange (ETDEWEB)

    Chudakov, Eugene A. [JLAB

    2013-11-01

    A new generation of precise Parity-Violating experiments will require a sub-percent accuracy of electron beam polarimetry. Compton polarimetry can provide such accuracy at high energies, but at a few hundred MeV the small analyzing power limits the sensitivity. M{\\o}ller polarimetry provides a high analyzing power independent on the beam energy, but is limited by the properties of the polarized targets commonly used. Options for precision polarimetry at ~300 MeV will be discussed, in particular a proposal to use ultra-cold atomic hydrogen traps to provide a 100\\%-polarized electron target for M{\\o}ller polarimetry.

  4. Improved electron transport layer

    DEFF Research Database (Denmark)

    2012-01-01

    The present invention provides: a method of preparing a coating ink for forming a zinc oxide electron transport layer, comprising mixing zinc acetate and a wetting agent in water or methanol; a coating ink comprising zinc acetate and a wetting agent in aqueous solution or methanolic solution...

  5. Using Electronic Portfolios

    Science.gov (United States)

    Page, Deb

    2012-01-01

    The digitized collections of artifacts known as electronic portfolios are creating solutions to a variety of performance improvement needs in ways that are cost-effective and improve both individual and group learning and performance. When social media functionality is embedded in e-portfolios, the tools support collaboration, social learning,…

  6. Quantitative Electron Nanodiffraction.

    Energy Technology Data Exchange (ETDEWEB)

    Spence, John [Arizona State Univ., Mesa, AZ (United States)

    2015-01-30

    This Final report summarizes progress under this award for the final reporting period 2002 - 2013 in our development of quantitive electron nanodiffraction to materials problems, especially devoted to atomistic processes in semiconductors and electronic oxides such as the new artificial oxide multilayers, where our microdiffraction is complemented with energy-loss spectroscopy (ELNES) and aberration-corrected STEM imaging (9). The method has also been used to map out the chemical bonds in the important GaN semiconductor (1) used for solid state lighting, and to understand the effects of stacking sequence variations and interfaces in digital oxide superlattices (8). Other projects include the development of a laser-beam Zernike phase plate for cryo-electron microscopy (5) (based on the Kapitza-Dirac effect), work on reconstruction of molecular images using the scattering from many identical molecules lying in random orientations (4), a review article on space-group determination for the International Tables on Crystallography (10), the observation of energy-loss spectra with millivolt energy resolution and sub-nanometer spatial resolution from individual point defects in an alkali halide, a review article for the Centenary of X-ray Diffration (17) and the development of a new method of electron-beam lithography (12). We briefly summarize here the work on GaN, on oxide superlattice ELNES, and on lithography by STEM.

  7. Inventing the Electronic University

    Science.gov (United States)

    Lewis, David W.

    2015-01-01

    Higher education is confronting a fundamental change. The transition from print on paper to digital and electronic technologies is transforming instruction, scholarly communication, and the storage and preservation of knowledge. What is required is not the automation of old systems, but the restructuring of institutions. The drive for autonomy,…

  8. Power Electronics Thermal Management

    Energy Technology Data Exchange (ETDEWEB)

    Moreno, Gilberto [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-08-07

    Thermal modeling was conducted to evaluate and develop thermal management strategies for high-temperature wide-bandgap (WBG)-based power electronics systems. WBG device temperatures of 175 degrees C to 250 degrees C were modeled under various under-hood temperature environments. Modeling result were used to identify the most effective capacitor cooling strategies under high device temperature conditions.

  9. Polymer Electronics, Quo Vadis?

    NARCIS (Netherlands)

    Chiechi, Ryan C.; Hummelen, Jan C.

    2012-01-01

    At the heart of polymer electronics lies more than three decades of research into conjugated polymers. The future of these materials is intimately tied to the development of organic photovoltaic (OPV) devices that can compete with traditional, inorganic devices in efficiency and cost. In addition to

  10. Polymer Electronics, Quo Vadis?

    NARCIS (Netherlands)

    Chiechi, Ryan C.; Hummelen, Jan C.

    2012-01-01

    At the heart of polymer electronics lies more than three decades of research into conjugated polymers. The future of these materials is intimately tied to the development of organic photovoltaic (OPV) devices that can compete with traditional, inorganic devices in efficiency and cost. In addition to

  11. Electronic Inspection of Beef

    Science.gov (United States)

    Anselmo, Victor J.; Gammell, Paul M.; Clark, Jerry

    1987-01-01

    Two proposed methods for grading beef quality based on inspection by electronic equipment: one method uses television camera to generate image of a cut of beef as customer sees it; other uses ultrasonics to inspect live animal or unsliced carcasses. Both methods show promise for automated meat inspection.

  12. The electronic stethoscope.

    Science.gov (United States)

    Leng, Shuang; Tan, Ru San; Chai, Kevin Tshun Chuan; Wang, Chao; Ghista, Dhanjoo; Zhong, Liang

    2015-07-10

    Most heart diseases are associated with and reflected by the sounds that the heart produces. Heart auscultation, defined as listening to the heart sound, has been a very important method for the early diagnosis of cardiac dysfunction. Traditional auscultation requires substantial clinical experience and good listening skills. The emergence of the electronic stethoscope has paved the way for a new field of computer-aided auscultation. This article provides an in-depth study of (1) the electronic stethoscope technology, and (2) the methodology for diagnosis of cardiac disorders based on computer-aided auscultation. The paper is based on a comprehensive review of (1) literature articles, (2) market (state-of-the-art) products, and (3) smartphone stethoscope apps. It covers in depth every key component of the computer-aided system with electronic stethoscope, from sensor design, front-end circuitry, denoising algorithm, heart sound segmentation, to the final machine learning techniques. Our intent is to provide an informative and illustrative presentation of the electronic stethoscope, which is valuable and beneficial to academics, researchers and engineers in the technical field, as well as to medical professionals to facilitate its use clinically. The paper provides the technological and medical basis for the development and commercialization of a real-time integrated heart sound detection, acquisition and quantification system.

  13. The Art of Electronics

    Science.gov (United States)

    Horowitz, Paul; Hill, Winfield

    2015-04-01

    1. Foundations; 2. Bipolar transistors; 3. Field effect transistors; 4. Operational amplifiers; 5. Precision circuits; 6. Filters; 7. Oscillators and timers; 8. Low noise techniques and transimpedance; 9. Power regulation; 10. Digital electronics; 11. Programmable logic devices; 12. Logical interfacing; 13. Digital meets analog; 14. Computers, controllers, and data links; 15. Microcontrollers.

  14. Unconditionally Secure Electronic Voting

    Science.gov (United States)

    Otsuka, Akira; Imai, Hideki

    In this chapter, we will show how to achieve unconditional or information-theoretic security in electronic voting with the following property: 1 Even all voters and tallying authorities have unbounded computing power, the distorted integrity of the voting results can be detected and proved incorrect by every honest voter,

  15. Electronic waste recycling techniques

    CERN Document Server

    Bernardes, Andréa

    2015-01-01

    This book presents an overview of the characterization of electronic waste. In addition, processing techniques for the recovery of metals, polymers and ceramics are described. This book serves as a source of information and as an educational technical reference for practicing scientists and engineers, as well as for students.

  16. Using Electronic Portfolios

    Science.gov (United States)

    Page, Deb

    2012-01-01

    The digitized collections of artifacts known as electronic portfolios are creating solutions to a variety of performance improvement needs in ways that are cost-effective and improve both individual and group learning and performance. When social media functionality is embedded in e-portfolios, the tools support collaboration, social learning,…

  17. Electron microscope studies

    Energy Technology Data Exchange (ETDEWEB)

    Crewe, A.V.; Kapp, O.H.

    1990-08-01

    Our laboratory has made significant progress this year in devising improved electron-optical systems, in studying invertebrate hemoglobins with the STEM, and in achieving a workable sub-angstrom STEM. Our goal in electron optics is to improve resolution by producing spherical and chromatic aberration coefficients with signs opposite those of magnetic lenses. We have progressed toward this goal through calculations that explore the addition of electrodes to electron mirrors to reduce these two geometric aberrations and by devising a beam separation system that won't introduce asymmetrical aberrations. Some promising new designs of magnetic lenses for SEM applications have also been investigated. We have continued our exploration of the quaternary structure of the invertebrate hemoglobins and are now among the top laboratories in this area of expertise. In addition, we have overcome many of our electronic difficulties on the sub-angstrom STEM and have made significant progress toward achieving an operational system. The addition of an IBM RISC-6000 workstation to our lab has significantly increased our image processing capabilities.

  18. The Electronic Student Portfolio.

    Science.gov (United States)

    Fasick, Emily; McLaren, Clemence

    1995-01-01

    Describes the use of electronic portfolios in one Hawaiian secondary literature class. Students went through their journals, picked two entries that best represented their growth in reading during the course, and explained why. Next they created a presentation about their growth and enjoyment of literature using multimedia technology. (SM)

  19. Electronic and Microelectronic Capabilities.

    Science.gov (United States)

    1982-07-01

    22 3.9 Aztec Products Custom Wet-Chemistry Line ........................................... 22 3.10 KotIrnorgen...Cofight Vertical Rotary Etcher............*....................................................... 22 11. Aztec Products Custom Wet-Chemistry Line...state of the art in thick film hybrid fabrication methods, microelectronic fabrication and assembly, PC board fabrication, and electronic board assembly

  20. Electronic Resource Management Systems

    Directory of Open Access Journals (Sweden)

    Mark Ellingsen

    2004-10-01

    Full Text Available Computer applications which deal with electronic resource management (ERM are quite a recent development. They have grown out of the need to manage the burgeoning number of electronic resources particularly electronic journals. Typically, in the early years of e-journal acquisition, library staff provided an easy means of accessing these journals by providing an alphabetical list on a web page. Some went as far as categorising the e-journals by subject and then grouping the journals either on a single web page or by using multiple pages. It didn't take long before it was recognised that it would be more efficient to dynamically generate the pages from a database rather than to continually edit the pages manually. Of course, once the descriptive metadata for an electronic journal was held within a database the next logical step was to provide administrative forms whereby that metadata could be manipulated. This in turn led to demands for incorporating more information and more functionality into the developing application.

  1. Selection of Electronic Resources.

    Science.gov (United States)

    Weathers, Barbara

    1998-01-01

    Discusses the impact of electronic resources on collection development; selection of CD-ROMs, (platform, speed, video and sound, networking capability, installation and maintenance); selection of laser disks; and Internet evaluation (accuracy of content, authority, objectivity, currency, technical characteristics). Lists Web sites for evaluating…

  2. Electron-Cyclotron Waves

    NARCIS (Netherlands)

    Westerhof, E.

    1994-01-01

    The essential elements of the theory of electron cyclotron waves are reviewed, The two main electro-magnetic modes of propagation are identified and their dispersion and absorption properties are discussed. The importance of the use of the relativistic resonance condition is stressed.

  3. Advanced Electronic Technology.

    Science.gov (United States)

    1980-05-15

    Silicon De- D.,I. Silversmith Solid State Technol. 23, 88 vices Formed by Ion Iniplanta- 1. W. Mountain (1980) tion and Laser Annealing S.C. Munroe M...J. Silversmith Photodeposition R. M. Osgood, Jr. 5075 Picosecond Optical Sampling H. A. Haus* Accepted by IEEE J. Quantum S.T. Kirsch Electron. K

  4. Cold electronics: an overview

    Science.gov (United States)

    Kirschman, R. K.

    Low-temperature operation is being applied and contemplated for electronic systems ranging from single-transistor circuits for basic research to VLSI integrated circuits for ultra-fast computers. It is seen as both a means of extracting better performance from present technology and as an important ingredient of the next generation of devices and circuits. This overview is concerned with electronics based on semiconductors; for low temperatures the primary material is Si, although GaAs also has considerable potential, and the primary device is the field-effect transistor in various forms. Reduced temperature operation offers improvements in performance through improvement of materials-related properties such as electronic carrier mobility, thermal conductivity, and electrical conductivity. Substantial improvements in reliability are also expected since degradation mechanisms are thermally activated; however, this could be negated unless problems of thermal expansion mismatch and cycling are overcome. Refrigeration continues to be a central concern; mechanical cycles are still the mainstay and progress is being made in systems applicable to electronics, although further development is needed.

  5. The Electronic Battle Box

    Science.gov (United States)

    Gouin, Denis; Turcotte, Guy; Lebel, Eric; Gilbert, Annie

    2000-08-01

    The Electronic Battle Box is an integrated suite of planning and decision-aid tools specially designed to facilitate Canadian Armed Force Officers during their training and during their tasks of preparing and conducting military operations. It is the result of a collaborative effort between the Defence Research Establishment Valcartier, the Directorate of Army Doctrine (DAD), the Directorate of Land Requirements (DLR), the G4 staff of 1Cdn Div HQ and CGI Information and Management Consultants Inc. Distributed on CD-ROM, the Electronic Battle Box contains efficient and user-friendly tools that significantly reduce the planning time for military operations and ensure staff officers a better focus on significant tasks. Among the tools are an OrBat Browser and an Equipment Browser allowing to view and edit military organizations, a Task Browser providing facilities to prepare plans using Gantt charts, a Logistic Planner allowing to estimate supply requirements applying complex calculations, and Road, Air and Rail Movement Planners. EBB also provides staff officers with a large set of doctrinal documents in an electronic format. This paper provides an overview of the various tools of the Electronic Battle Box.

  6. The electronic neighbourhood

    DEFF Research Database (Denmark)

    Rüdiger, Bjarne; Tournay, Bruno

    2004-01-01

    This paper presents the results of a 3-year research project. The Electronic Neighbourhood (2000-2004). Researchers have developed and tested a digital model of the urban area and other digital tools for supporting the dialogue and cooperation between professionals and citizens in an urban...... regeneration project in Copenhagen....

  7. Electronics and Electromagnetism

    Science.gov (United States)

    Nièpce, J.-C.; Givord, D.

    Multilayer ceramic capacitors (MLCC) are the capacitors most commonly used in electronic circuits (television, radio, telephone, automobile, aeronautics, space, etc.). The main advantages are low cost, small size, a good level of chemical inertness, due to the fact that they are made from chemically very stable oxide ceramics, and hence good stability in time.

  8. ELECTRON COOLING FOR RHIC.

    Energy Technology Data Exchange (ETDEWEB)

    BEN-ZVI,I.

    2001-05-13

    The Accelerator Collider Department (CAD) at Brookhaven National Laboratory is operating the Relativistic Heavy Ion Collider (RHIC), which includes the dual-ring, 3.834 km circumference superconducting collider and the venerable AGS as the last part of the RHIC injection chain. CAD is planning on a luminosity upgrade of the machine under the designation RHIC II. One important component of the RHIC II upgrade is electron cooling of RHIC gold ion beams. For this purpose, BNL and the Budker Institute of Nuclear Physics in Novosibirsk entered into a collaboration aimed initially at the development of the electron cooling conceptual design, resolution of technical issues, and finally extend the collaboration towards the construction and commissioning of the cooler. Many of the results presented in this paper are derived from the Electron Cooling for RHIC Design Report [1], produced by the, BINP team within the framework of this collaboration. BNL is also collaborating with Fermi National Laboratory, Thomas Jefferson National Accelerator Facility and the University of Indiana on various aspects of electron cooling.

  9. Active devices for electronics

    CERN Document Server

    Sowa, Walter A

    1971-01-01

    An introduction to semiconductors ; the p-n junction ; the junction transistor ; electrical characteristics and ratings ; basic transistor amplifiers ; the field-effect transistor ; the unijunction transistor (UJT) ; the silicon controlled rectifier (SCR) ; the DIAC and TRIAC ; light operated devices ; integrated circuits (ICs) ; other solid-state devices of interest ; electron tubes.

  10. Nucleus Driven Electronic Pulsation

    CERN Document Server

    Ludwig, H; Xue, S -S

    2014-01-01

    We derive and solve by the spectral method the equations for a neutral system of ultra-relativistic electrons that are compressed to the radius of the nucleus and subject to a driving force. This driving force can be thought of as originating from a nuclear breathing mode, a possibility we discuss in detail.

  11. Electronically Enhanced Classroom Interaction.

    Science.gov (United States)

    Draper, Stephen; Cargill, Julie; Cutts, Quintin

    A design rationale for introducing electronic equipment (a group response system) for student interaction in lecture theaters is presented, linking the instructional design to theory. The effectiveness of the equipment for learning depends mostly on what pedagogic method is employed. Various alternative types are introduced, including: assessment;…

  12. Adaptive municipal electronic forms

    NARCIS (Netherlands)

    Kuiper, Pieter; Dijk, van Betsy; Bondarouk, Tanya; Ruël, Huub; Guiderdoni-Jourdain, Karine; Oiry, Ewan

    2009-01-01

    Adaptation of electronic forms (e-forms) seems to be a step forward to reduce the burden for people who fill in forms. Municipalities more and more offer e-forms online that can be used by citizens to request a municipal product or service or by municipal employees to place a request on behalf of a

  13. Forensic Scanning Electron Microscope

    Science.gov (United States)

    Keeley, R. H.

    1983-03-01

    The scanning electron microscope equipped with an x-ray spectrometer is a versatile instrument which has many uses in the investigation of crime and preparation of scientific evidence for the courts. Major applications include microscopy and analysis of very small fragments of paint, glass and other materials which may link an individual with a scene of crime, identification of firearms residues and examination of questioned documents. Although simultaneous observation and chemical analysis of the sample is the most important feature of the instrument, other modes of operation such as cathodoluminescence spectrometry, backscattered electron imaging and direct x-ray excitation are also exploited. Marks on two bullets or cartridge cases can be compared directly by sequential scanning with a single beam or electronic linkage of two instruments. Particles of primer residue deposited on the skin and clothing when a gun is fired can be collected on adhesive tape and identified by their morphology and elemental composition. It is also possible to differentiate between the primer residues of different types of ammunition. Bullets may be identified from the small fragments left behind as they pass through the body tissues. In the examination of questioned documents the scanning electron microscope is used to establish the order in which two intersecting ink lines were written and to detect traces of chemical markers added to the security inks on official documents.

  14. Newnes electronics assembly pocket book

    CERN Document Server

    Brindley, Keith

    2013-01-01

    Produced in association with the Engineering Training Authority with contributions from dozens of people in the electronics industry. The material covers common skills in electrical and electronic engineering and concentrates mainly on wiring and assembly. 'Newnes Electronics Assembly Pocket Book' is for electronics technicians, students and apprentices.

  15. Electronic Library: A TERI Experiment.

    Science.gov (United States)

    Kar, Debal C.; Deb, Subrata; Kumar, Satish

    2003-01-01

    Discusses the development of Electronic Library at TERI (The Energy and Resources Institute, New Delhi). Highlights include: hardware and software used; the digital library/Virtual Electronic Library; directory of Internet journals; virtual reference resources; electronic collection/Physical Electronic Library; downloaded online full-length…

  16. The electronic structures of solids

    CERN Document Server

    Coles, B R

    2013-01-01

    The Electronic Structures of Solids aims to provide students of solid state physics with the essential concepts they will need in considering properties of solids that depend on their electronic structures and idea of the electronic character of particular materials and groups of materials. The book first discusses the electronic structure of atoms, including hydrogen atom and many-electron atom. The text also underscores bonding between atoms and electrons in metals. Discussions focus on bonding energies and structures in the solid elements, eigenstates of free-electron gas, and electrical co

  17. Basic principles of electronics thermionics

    CERN Document Server

    Jenkins, J

    2013-01-01

    Basic Principles of Electronics, Volume I: Thermionics covers topics related to thermionic devices. The book starts by providing a physical background about electronics, including structure of matter, ionic, chemical and covalent combination, crystalline structure, conductors and insulators, and thermionic emission. The text then discusses electron dynamics; the characteristics and properties of electrons in solids; electron emission; and thermionic emission in a vacuum diode or triode. The development of the vacuum triode; gas-filled valves; and power amplifiers are also considered. The book

  18. Electronic Commerce Removing Regulatory Impediments

    Science.gov (United States)

    1992-05-01

    AD-A252 691 ELECTRONIC COMMERCE Removing Regulatory Impediments ~DuiG A% ELECTE I JUL1 8 1992 0 C D Daniel J. Drake John A. Ciucci ... - ""N ST AT KE...Management Institute 6400 Goldsboro Road Bethesda, Maryland 20817-5886 92 LMI Executive Summary ELECTRONIC COMMERCE : REMOVING REGULATORY IMPEDIMENTS... Electronic Commerce techniques, such as electronic mail and electronic data interchange (EDI), enable Government agencies to conduct business without the

  19. Electron scattering for exotic nuclei

    Indian Academy of Sciences (India)

    Toshimi Suda

    2014-11-01

    A brand-new electron scattering facility, the SCRIT Electron Scattering Facility, will soon start its operation at RIKEN RI Beam Factory, Japan. This is the world’s first electron scattering facility dedicated to the structure studies of short-lived nuclei. The goal of this facility is to determine the charge density distributions of short-lived exotic nuclei by elastic electron scattering. The first collision between electrons and exotic nuclei will be observed in the year 2014.

  20. PREFACE: Correlated Electrons (Japan)

    Science.gov (United States)

    Miyake, Kazumasa

    2007-03-01

    This issue of Journal of Physics: Condensed Matter is dedicated to results in the field of strongly correlated electron systems under multiple-environment. The physics of strongly correlated electron systems (SCES) has attracted much attention since the discovery of superconductivity in CeCu_2 Si_2 by Steglich and his co-workers a quater-century ago. Its interest has been intensified by the discovery of high-Tc superconductivity in a series of cuprates with layered perovskite structure which are still under active debate. The present issue of Journal of Physics: Condensed Matter present some aspects of SCES physics on the basis of activities of a late project "Centre-Of-Excellence" supported by MEXT (Ministry of Education, Sports, Science, Culture and Technology of the Japanese Government). This project has been performed by a condensed matter physics group in the faculties of science and engineering science of Osaka University. Although this project also covers correlated phenomena in optics and nano-scale systems, we focus here on the issues of SCES related to superconductivity, mainly unconventional. The present issue covers the discussions on a new mechanism of superconductivity with electronic origin (critical valence fluctuation mechanism), interplay and unification of magnetism and superconductivity in SCES based on a systematic study of NQR under pressure, varieties of Fermi surface of Ce- and U-based SCES probed by the de Haas-van Alphen effect, electronic states probed by a bulk sensitive photoemission spectroscopy with soft X-ray, pressure induced superconductivity of heavy electron materials, pressure dependence of superconducting transition temperature based on a first-principle calculation, and new superconductors under very high-pressure. Some papers offer readers' reviews of the relevant fields and/or include new developments of this intriguing research field of SCES. Altogether, the papers within this issue outline some aspects of electronic states

  1. Electronic health record

    DEFF Research Database (Denmark)

    Kierkegaard, Patrick

    2011-01-01

    The European Commission wants to boost the digital economy by enabling all Europeans to have access to online medical records anywhere in Europe by 2020. With the newly enacted Directive 2011/24/EU on Patients’ Rights in cross border healthcare due for implementation by 2013, it is inevitable...... that a centralised European health record system will become a reality even before 2020. However, the concept of a centralised supranational central server raises concern about storing electronic medical records in a central location. The privacy threat posed by a supranational network is a key concern. Cross border...... and Interoperable electronic health record systems make confidential data more easily and rapidly accessible to a wider audience and increases the risk that personal data concerning health could be accidentally exposed or easily distributed to unauthorised parties by enabling greater access to a compilation...

  2. Electronic health records

    DEFF Research Database (Denmark)

    Kierkegaard, Patrick

    2011-01-01

    The European Commission wants to boost the digital economy by enabling all Europeans to have access to online medical records anywhere in Europe by 2020. With the newly enacted Directive 2011/24/EU on patients’ rights in cross-border healthcare due for implementation by 2013, it is inevitable...... that a centralised European health record system will become a reality even before 2020. However, the concept of a centralised supranational central server raises concern about storing electronic medical records in a central location. The privacy threat posed by a supranational network is a key concern. Cross......-border and Interoperable electronic health record systems make confidential data more easily and rapidly accessible to a wider audience and increase the risk that personal data concerning health could be accidentally exposed or easily distributed to unauthorised parties by enabling greater access to a compilation...

  3. Uniform quantized electron gas

    Science.gov (United States)

    Høye, Johan S.; Lomba, Enrique

    2016-10-01

    In this work we study the correlation energy of the quantized electron gas of uniform density at temperature T  =  0. To do so we utilize methods from classical statistical mechanics. The basis for this is the Feynman path integral for the partition function of quantized systems. With this representation the quantum mechanical problem can be interpreted as, and is equivalent to, a classical polymer problem in four dimensions where the fourth dimension is imaginary time. Thus methods, results, and properties obtained in the statistical mechanics of classical fluids can be utilized. From this viewpoint we recover the well known RPA (random phase approximation). Then to improve it we modify the RPA by requiring the corresponding correlation function to be such that electrons with equal spins can not be on the same position. Numerical evaluations are compared with well known results of a standard parameterization of Monte Carlo correlation energies.

  4. Basics of RF electronics

    CERN Document Server

    Gallo, A

    2011-01-01

    RF electronics deals with the generation, acquisition and manipulation of high-frequency signals. In particle accelerators signals of this kind are abundant, especially in the RF and beam diagnostics systems. In modern machines the complexity of the electronics assemblies dedicated to RF manipulation, beam diagnostics, and feedbacks is continuously increasing, following the demands for improvement of accelerator performance. However, these systems, and in particular their front-ends and back-ends, still rely on well-established basic hardware components and techniques, while down-converted and acquired signals are digitally processed exploiting the rapidly growing computational capability offered by the available technology. This lecture reviews the operational principles of the basic building blocks used for the treatment of high-frequency signals. Devices such as mixers, phase and amplitude detectors, modulators, filters, switches, directional couplers, oscillators, amplifiers, attenuators, and others are d...

  5. Electron-molecule collisions

    CERN Document Server

    Takayanagi, Kazuo

    1984-01-01

    Scattering phenomena play an important role in modern physics. Many significant discoveries have been made through collision experiments. Amongst diverse kinds of collision systems, this book sheds light on the collision of an electron with a molecule. The electron-molecule collision provides a basic scattering problem. It is scattering by a nonspherical, multicentered composite particle with its centers having degrees of freedom of motion. The molecule can even disintegrate, Le., dissociate or ionize into fragments, some or all of which may also be molecules. Although it is a difficult problem, the recent theoretical, experimental, and computational progress has been so significant as to warrant publication of a book that specializes in this field. The progress owes partly to technical develop­ ments in measurements and computations. No less important has been the great and continuing stimulus from such fields of application as astrophysics, the physics of the earth's upper atmosphere, laser physics, radiat...

  6. Conversion electron surface imaging

    CERN Document Server

    Irwin, G M; Wehner, A

    1999-01-01

    A method of imaging the Moessbauer absorption over the surface of a sample based on counting conversion electrons emitted from the surface following resonant absorption of gamma radiation is described. This Conversion Electron Surface Imaging (CESI) method is somewhat analogous to Magnetic Resonance Imaging (MRI), particularly chemical shift imaging, and similar tomographic reconstruction techniques are involved in extracting the image. The theory behind the technique and a prototype device is described, as well as the results of proof-of-principle experiments which demonstrate the function of the device. Eventually this same prototype device will be part of a system to determine the spatial variation of the Moessbauer spectrum over the surface of a sample. Applications include imaging of variations of surface properties of steels and other iron containing alloys, as well as other surfaces over which sup 5 sup 7 Fe has been deposited.

  7. Semiconductor Physical Electronics

    CERN Document Server

    Li, Sheng

    2006-01-01

    Semiconductor Physical Electronics, Second Edition, provides comprehensive coverage of fundamental semiconductor physics that is essential to an understanding of the physical and operational principles of a wide variety of semiconductor electronic and optoelectronic devices. This text presents a unified and balanced treatment of the physics, characterization, and applications of semiconductor materials and devices for physicists and material scientists who need further exposure to semiconductor and photonic devices, and for device engineers who need additional background on the underlying physical principles. This updated and revised second edition reflects advances in semicondutor technologies over the past decade, including many new semiconductor devices that have emerged and entered into the marketplace. It is suitable for graduate students in electrical engineering, materials science, physics, and chemical engineering, and as a general reference for processing and device engineers working in the semicondi...

  8. Keeping electronic records secure.

    Science.gov (United States)

    Easton, David

    2013-10-01

    Are electronic engineering maintenance records relating to the hospital estate or a medical device as important as electronic patient records? Computer maintenance management systems (CMMS) are increasingly being used to manage all-round maintenance activities. However, the accuracy of the data held on them, and a level of security that prevents tampering with records, or other unauthorised changes to them to 'cover' poor practice, are both essential, so that, should an individual be injured or killed on hospital grounds, and a law suit follow, the estates team can be confident that it has accurate data to prove it has fulfilled its duty of care. Here David Easton MSc CEng FIHEEM MIET, director of Zener Engineering Services, and chair of IHEEM's Medical Devices Advisory Group, discusses the issues around maintenance databases, and the security and integrity of maintenance data.

  9. Electron beam silicon purification

    Energy Technology Data Exchange (ETDEWEB)

    Kravtsov, Anatoly [SIA ' ' KEPP EU' ' , Riga (Latvia); Kravtsov, Alexey [' ' KEPP-service' ' Ltd., Moscow (Russian Federation)

    2014-11-15

    Purification of heavily doped electronic grade silicon by evaporation of N-type impurities with electron beam heating was investigated in process with a batch weight up to 50 kilos. Effective temperature of the melt, an indicative parameter suitable for purification process characterization was calculated and appeared to be stable for different load weight processes. Purified material was successfully approbated in standard CZ processes of three different companies. Each company used its standard process and obtained CZ monocrystals applicable for photovoltaic application. These facts enable process to be successfully scaled up to commercial volumes (150-300 kg) and yield solar grade silicon. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  10. Electron Beam Ion Sources

    CERN Document Server

    Zschornacka, G.; Thorn, A.

    2013-12-16

    Electron beam ion sources (EBISs) are ion sources that work based on the principle of electron impact ionization, allowing the production of very highly charged ions. The ions produced can be extracted as a DC ion beam as well as ion pulses of different time structures. In comparison to most of the other known ion sources, EBISs feature ion beams with very good beam emittances and a low energy spread. Furthermore, EBISs are excellent sources of photons (X-rays, ultraviolet, extreme ultraviolet, visible light) from highly charged ions. This chapter gives an overview of EBIS physics, the principle of operation, and the known technical solutions. Using examples, the performance of EBISs as well as their applications in various fields of basic research, technology and medicine are discussed.

  11. Pursuing prosthetic electronic skin

    Science.gov (United States)

    Chortos, Alex; Liu, Jia; Bao, Zhenan

    2016-09-01

    Skin plays an important role in mediating our interactions with the world. Recreating the properties of skin using electronic devices could have profound implications for prosthetics and medicine. The pursuit of artificial skin has inspired innovations in materials to imitate skin's unique characteristics, including mechanical durability and stretchability, biodegradability, and the ability to measure a diversity of complex sensations over large areas. New materials and fabrication strategies are being developed to make mechanically compliant and multifunctional skin-like electronics, and improve brain/machine interfaces that enable transmission of the skin's signals into the body. This Review will cover materials and devices designed for mimicking the skin's ability to sense and generate biomimetic signals.

  12. Pulsed electron beam precharger

    Energy Technology Data Exchange (ETDEWEB)

    Finney, W.C. (ed.); Shelton, W.N.

    1991-01-01

    Electron beam precharging of a high resistivity aerosol was successfully demonstrated during this reporting period (Quarters Five and Six). The initial E-beam particle precharging experiments completed this term were designed to confirm and extend some of the work performed under the previous contract. There are several reasons for doing this: (1) to re-establish a baseline performance criterion for comparison to other runs, (2) to test several recently upgraded or repaired subsystems, and (3) to improve upon the collection efficiency of the electron beam precipitator when testing precharging effectiveness with a very high resistivity, moderate-to-high concentration dust load. In addition, these shakedown runs were used to determine a set of suitable operational parameters for the wind tunnel, the electrostatic collecting sections, and the MINACC E-beam accelerator. These parameters will generally be held constant while the precharging parameters are varied to produce an optimum particle charge.

  13. Power electronics reliability.

    Energy Technology Data Exchange (ETDEWEB)

    Kaplar, Robert James; Brock, Reinhard C.; Marinella, Matthew; King, Michael Patrick; Stanley, James K.; Smith, Mark A.; Atcitty, Stanley

    2010-10-01

    The project's goals are: (1) use experiments and modeling to investigate and characterize stress-related failure modes of post-silicon power electronic (PE) devices such as silicon carbide (SiC) and gallium nitride (GaN) switches; and (2) seek opportunities for condition monitoring (CM) and prognostics and health management (PHM) to further enhance the reliability of power electronics devices and equipment. CM - detect anomalies and diagnose problems that require maintenance. PHM - track damage growth, predict time to failure, and manage subsequent maintenance and operations in such a way to optimize overall system utility against cost. The benefits of CM/PHM are: (1) operate power conversion systems in ways that will preclude predicted failures; (2) reduce unscheduled downtime and thereby reduce costs; and (3) pioneering reliability in SiC and GaN.

  14. Recycling of electronic scrap

    DEFF Research Database (Denmark)

    Legarth, Jens Brøbech

    This Ph.D. thesis deals with the growingly important field of electronics recycling with special attention to the problem of printed circuit board recycling. A literature survey of contemporary electronics recycling and printed circuit board recycling is presented.Further, an analysis of the role...... in the metals producing industry is presented and tested on two printed circuit board scrap cases. The underlying idea for the method is that complex scrap should be introduced in the matrix of man-made material flows at recipient points where the scrap constitutes the least environmental problem and where...... resource recovery is largest. It is clearly shown with the two printed circuit board scrap cases that the currently used copper recycling scenario is environmentally inferior to the tin and lead primary production scenarios. The method is a novelty, since no-one has previously put forward a method...

  15. Electronics Technician 3

    Science.gov (United States)

    1957-01-01

    grade of of a strong, pliable wood strip and securing sandpaper (No. 00) may be used. Sandpapering the canvas with rivets, as shown in figure is also...and use properly personnel. insulated tools; cover the deck with an approved All electronics personnel must become thor- insulating material; and make...not struction, the worker must be insulated from be broken except when absolutely necessary and accidental grounding by the use of approved authorized

  16. Runaway electrons and Bremsstrahlung

    Science.gov (United States)

    Helander, Per

    2016-09-01

    If an electric field is applied to a plasma, it causes ‘runaway’ acceleration of some electrons—a phenomenon that has been known for almost a century. A paper by Embréus et al (2016 New J. Phys. 18 093023) calculates how the emission of Bremsstrahlung affects the upper end of the energy spectrum of these electrons, and finds that it is important to carefully account for finite energy of the emitted photons.

  17. Shipboard electronics thermoacoustic cooler

    OpenAIRE

    Ballister, Stephen C.; McKelvey, Dennis J.

    1995-01-01

    A thermoacoustic refrigerator that was optimized for preservation of biological samples in space, was modified for use as a cooler for the CV-2095 shipboard radar electronics rack. The thermoacoustic cooler was tested in the laboratory and demonstrated at sea aboard USS DEYO (DD-989). In the laboratory, using a calibrated heat load, the data acquisition system was able to account for the total energy balance to within 4%. At the highest operating power aboard ship, 226.6 Watts of acoustic pow...

  18. Electronic healthcare information security

    CERN Document Server

    Dube, Kudakwashe; Shoniregun, Charles A

    2010-01-01

    The ever-increasing healthcare expenditure and pressing demand for improved quality and efficiency of patient care services are driving innovation in healthcare information management. The domain of healthcare has become a challenging testing ground for information security due to the complex nature of healthcare information and individual privacy. ""Electronic Healthcare Information Security"" explores the challenges of e-healthcare information and security policy technologies. It evaluates the effectiveness of security and privacy implementation systems for anonymization methods and techniqu

  19. Electronic Braille Document Reader

    OpenAIRE

    Arif, Shahab; Holmes, Violeta

    2013-01-01

    This paper presents an investigation into developing a portable Braille device which would allow visually impaired individuals to read electronic documents by actuating Braille text on a finger. Braille books tend to be bulky in size due to the minimum size requirements for each Braille cell. E-books can be read in Braille using refreshable Braille displays connected to a computer. However, the refreshable Braille displays are expensive, bulky and are not portable. These factors restrict blin...

  20. Towards Hypermedia Electronic Publishing

    OpenAIRE

    Konstantas, Dimitri; Morin, Jean-Henry

    1995-01-01

    The most important problem that decision makers face in today's ever increasing information flux is how to find efficiently and fast the useful information. Hypermedia Electronic Publishing systems, supporting active information distribution and offering hypertext browsing facilities, provide a promising solution to this problem. Nevertheless several issues, like value added services, retrieval and access mechanism, information marketing as well as financial and security aspects should be res...

  1. Xyce parallel electronic simulator.

    Energy Technology Data Exchange (ETDEWEB)

    Keiter, Eric R; Mei, Ting; Russo, Thomas V.; Rankin, Eric Lamont; Schiek, Richard Louis; Thornquist, Heidi K.; Fixel, Deborah A.; Coffey, Todd S; Pawlowski, Roger P; Santarelli, Keith R.

    2010-05-01

    This document is a reference guide to the Xyce Parallel Electronic Simulator, and is a companion document to the Xyce Users Guide. The focus of this document is (to the extent possible) exhaustively list device parameters, solver options, parser options, and other usage details of Xyce. This document is not intended to be a tutorial. Users who are new to circuit simulation are better served by the Xyce Users Guide.

  2. Electrical and electronic principles

    CERN Document Server

    Knight, S A

    1991-01-01

    Electrical and Electronic Principles, 2, Second Edition covers the syllabus requirements of BTEC Unit U86/329, including the principles of control systems and elements of data transmission. The book first tackles series and parallel circuits, electrical networks, and capacitors and capacitance. Discussions focus on flux density, electric force, permittivity, Kirchhoff's laws, superposition theorem, arrangement of resistors, internal resistance, and powers in a circuit. The text then takes a look at capacitors in circuit, magnetism and magnetization, electromagnetic induction, and alternating v

  3. Computational Electronics and Electromagnetics

    Energy Technology Data Exchange (ETDEWEB)

    DeFord, J.F.

    1993-03-01

    The Computational Electronics and Electromagnetics thrust area is a focal point for computer modeling activities in electronics and electromagnetics in the Electronics Engineering Department of Lawrence Livermore National Laboratory (LLNL). Traditionally, they have focused their efforts in technical areas of importance to existing and developing LLNL programs, and this continues to form the basis for much of their research. A relatively new and increasingly important emphasis for the thrust area is the formation of partnerships with industry and the application of their simulation technology and expertise to the solution of problems faced by industry. The activities of the thrust area fall into three broad categories: (1) the development of theoretical and computational models of electronic and electromagnetic phenomena, (2) the development of useful and robust software tools based on these models, and (3) the application of these tools to programmatic and industrial problems. In FY-92, they worked on projects in all of the areas outlined above. The object of their work on numerical electromagnetic algorithms continues to be the improvement of time-domain algorithms for electromagnetic simulation on unstructured conforming grids. The thrust area is also investigating various technologies for conforming-grid mesh generation to simplify the application of their advanced field solvers to design problems involving complicated geometries. They are developing a major code suite based on the three-dimensional (3-D), conforming-grid, time-domain code DSI3D. They continue to maintain and distribute the 3-D, finite-difference time-domain (FDTD) code TSAR, which is installed at several dozen university, government, and industry sites.

  4. Electronics Industry Study Report

    Science.gov (United States)

    2005-01-01

    which has reduced the use and allure of stock options . Another electronics industry official captured this problem saying, “It’s not that the talent...capital gains tax. China reduces its 17% nominal value-added tax to 3% for domestically manufactured semiconductors. China also taxes stock ... options at par value and has no capital gains tax. New fabs in Singapore receive a ten year tax exemption followed by a five year period of reduced tax

  5. Power Electronics System Communications

    OpenAIRE

    Milosavljevic, Ivana

    1999-01-01

    This work investigates communication issues in high-frequency power converters. A novel control communication network (Power Electronics System Network or PES Net) is proposed for modular, medium and high-power, converters. The network protocol, hardware and software are designed and implemented. The PES Net runs at 125 Mb/s over plastic optical fiber allowing converter switching frequencies in excess of 100 kHz. Communication control is implemented in a fie...

  6. Supernova electron capture rates

    CERN Document Server

    Martínez-Pinedo, G

    1999-01-01

    We have calculated the Gamow-Teller strength distributions for the ground states and low lying states of several nuclei that play an important role in the precollapse evolution of supernova. The calculations reproduce the experimental GT distributions nicely. The GT distribution are used to calculate electron capture rates for typical presupernova conditions. The computed rates are noticeably smaller than the presently adopted rates. The possible implications for the supernova evolution are discussed.

  7. ELECTRONIC COMMERCE PORTAL

    OpenAIRE

    Georgeta Soava

    2011-01-01

    Today companies are faced with the need to exploit technology changing computer environments, in order to improve customer satisfaction and reduce costs. A successful approach to electronic portals is an effective demonstration of the new ways of relating to the client. The objectives that we have considered for the realization of e-commerce portal can be summarized as follows: structured communication, effective collaboration, complet and closed circuit of orders and deliveries, inventory op...

  8. FRAUD IN ELECTRONIC COMMERCE

    OpenAIRE

    Valentin-Stelian Badescu

    2013-01-01

    Electronic commerce is experiencing a great extent, and about the same extent fraud seeks - and sometimes is the place to impressive levels. Moreover, computer fraud and, the actors' they do not seem to suffer from the global economic recession and get as sophisticated as a legitimate business model and one of the most important dimensions of the work of modern organizations is the manipulation of information (collection, processing, storage, distribution, etc.). This component informational ...

  9. The electronic approach VSCF

    Science.gov (United States)

    Hladky, Mark

    The advantages of the high-power electronic approach to variable speed constant frequency (VSCF) systems are examined. It is shown, in particular, how the inherent flexibility of the VSCF approach allows it to be configured for different applications, contributing to the evolution towards the more electric aircraft. The discussion covers criteria for selection, aircraft electric power system architectures, power level, performance, reliability, and maintainability. The future trends of the VSCF converter technology are also briefly discussed.

  10. Electron cryomicroscopy methods.

    Science.gov (United States)

    Unger, V M

    2001-10-01

    Electron cryomicroscopy methods comprise a rapidly expanding field providing insights into the structure and function of biological macromolecules and their supramolecular assemblies. The 3.8 A resolution structure of the membrane protein aquaporin, a view of the herpesvirus capsid at 8.5 A and the 10 A resolution structure of the spliceosomal U1 small nuclear ribonucleoprotein complex are three outstanding examples emphasizing the versatility of this technique.

  11. CERN Electronics Pool presentations

    CERN Multimedia

    2011-01-01

    The CERN Electronics Pool has organised a series of presentations in collaboration with oscilloscope manufacturers. The last one will take place according to the schedule below.   Time will be available at the end of the presentation to discuss your personal needs. The Agilent presentation had to be postponed and will be organised later. -     Lecroy: Thursday, 24 November 2011, in 530-R-030, 14:00 to 16:30.

  12. Implantable electronic medical devices

    CERN Document Server

    Fitzpatrick, Dennis

    2014-01-01

    Implantable Electronic Medical Devices provides a thorough review of the application of implantable devices, illustrating the techniques currently being used together with overviews of the latest commercially available medical devices. This book provides an overview of the design of medical devices and is a reference on existing medical devices. The book groups devices with similar functionality into distinct chapters, looking at the latest design ideas and techniques in each area, including retinal implants, glucose biosensors, cochlear implants, pacemakers, electrical stimulation t

  13. Sculpturing the Electron Wave Function

    CERN Document Server

    Shiloh, Roy; Lilach, Yigal; Arie, Ady

    2014-01-01

    Coherent electrons such as those in electron microscopes, exhibit wave phenomena and may be described by the paraxial wave equation. In analogy to light-waves, governed by the same equation, these electrons share many of the fundamental traits and dynamics of photons. Today, spatial manipulation of electron beams is achieved mainly using electrostatic and magnetic fields. Other demonstrations include simple phase-plates and holographic masks based on binary diffraction gratings. Altering the spatial profile of the beam may be proven useful in many fields incorporating phase microscopy, electron holography, and electron-matter interactions. These methods, however, are fundamentally limited due to energy distribution to undesired diffraction orders as well as by their binary construction. Here we present a new method in electron-optics for arbitrarily shaping of electron beams, by precisely controlling an engineered pattern of thicknesses on a thin-membrane, thereby molding the spatial phase of the electron wav...

  14. The SPEDE electron spectrometer

    CERN Document Server

    O'Neill, George

    This thesis presents SPEDE (SPectrometer for Electron DEtection) and documents its construction, testing and performance during commissioning at Jyvaskyla, Finland, before deployment at the HIE-ISOLDE facility at CERN coupled with the MINIBALL array to perform in-beam electron-gamma spectroscopy using post-accelerated radioactive ion beams. Commissioning experiments took place in two two-day stints during spring 2015, coupled with several JUROGAMII gamma-detectors. This spectrometer will help aid in fully understanding exotic regions of the nuclear chart such as regions with a high degree of octupole deformation, and in those nuclei exhibiting shape coexistence. For the rst time, electron spectroscopy has been performed at the target position from states populated in accelerated nuclei via Coulomb excitation. The FWHM of SPEDE is approximately 7 keV at 320 keV, and Doppler correction was possible to improve Doppler broadened peaks. The results are intended to give the reader a full understanding of the dete...

  15. Transformational silicon electronics

    KAUST Repository

    Rojas, Jhonathan Prieto

    2014-02-25

    In today\\'s traditional electronics such as in computers or in mobile phones, billions of high-performance, ultra-low-power devices are neatly integrated in extremely compact areas on rigid and brittle but low-cost bulk monocrystalline silicon (100) wafers. Ninety percent of global electronics are made up of silicon. Therefore, we have developed a generic low-cost regenerative batch fabrication process to transform such wafers full of devices into thin (5 μm), mechanically flexible, optically semitransparent silicon fabric with devices, then recycling the remaining wafer to generate multiple silicon fabric with chips and devices, ensuring low-cost and optimal utilization of the whole substrate. We show monocrystalline, amorphous, and polycrystalline silicon and silicon dioxide fabric, all from low-cost bulk silicon (100) wafers with the semiconductor industry\\'s most advanced high-κ/metal gate stack based high-performance, ultra-low-power capacitors, field effect transistors, energy harvesters, and storage to emphasize the effectiveness and versatility of this process to transform traditional electronics into flexible and semitransparent ones for multipurpose applications. © 2014 American Chemical Society.

  16. Electronic Recruitment at CERN

    CERN Multimedia

    2004-01-01

    The Human Resources Department switches to electronic recruitment. From now on whenever you are involved in a recruitment action you will receive an e-mail giving you access to a Web folder. Inside you will find a shortlist of applications drawn up by the Human Resources Department. This will allow you to consult the folder, at the same time as everyone else involved in the recruitment process, for the vacancy you are interested in. This new electronic recruitment system, known as e-RT, will be introduced in a presentation given at 10 a.m. on 11 February in the Main Auditorium. Implemented by AIS (Administrative Information Services) and the Human Resources Department, e-RT will cover vacancies open in all of CERN's recruitment programmes. The electronic application system was initially made available to technical students in July 2003. By December it was extended to summer students, fellows, associates and Local Staff. Geraldine Ballet from the Recruitment Service prefers e-RT to mountains of paper! The Hu...

  17. Pulsed electron beam precharger

    Energy Technology Data Exchange (ETDEWEB)

    Finney, W.C. (ed.); Shelton, W.N.

    1991-01-01

    During the previous reporting period (Quarter Six), the charging and removal of a fine, high resistivity aerosol using the advanced technology of electron beam precipitation was successfully accomplished. Precharging a dust stream circulating through the EBP wind tunnel produced collection efficiency figures of up to 40 times greater than with corona charging and collection alone (Table 1). The increased system collection efficiency attributed to electron beam precharging was determined to be the result of increased particle charge. It was found that as precharger electric field was raised, collection efficiency became greater. In sequence, saturation particle charge varies with the precharger electric field strength, particle migration velocity varies with the precharger and collector electric field, and collection efficiency varies with the migration velocity. Maximizing the system collection efficiency requires both a high charging electric field (provided by the E-beam precharger), and a high collecting electric field (provided by the collector wires and plates). Because increased particle collection efficiency is directly attributable to higher particle charge, the focus of research during Quarter Seven was shifted to learning more about the actual charge magnitude on the aerosol particles. Charge determinations in precipitators have traditionally been made on bulk dust samples collected from the flue gas stream, which gives an overall charge vs. mass (Q/M) ratio measurement. More recently, techniques have been developed which allow the measurement of the charge on individual particles in a rapid and repeatable fashion. One such advanced technique has been developed at FSU for use in characterizing the electron beam precharger.

  18. Electronic Health Object

    Directory of Open Access Journals (Sweden)

    Mohammad Nabil Almunawar PhD

    2015-12-01

    Full Text Available Electronic health records (EHRs store health-related patient information in an electronic format, improving the quality of health care management and increasing efficiency of health care processes. However, in existing information systems, health-related records are generated, managed, and controlled by health care organizations. Patients are perceived as recipients of care and normally cannot directly interact with the system that stores their health-related records; their participation in enriching this information is not possible. Many businesses now allow customers to participate in generating information for their systems, strengthening customer relationships. This trend is supported by Web 2.0, which enables interactivity through various means, including social networks. Health care systems should be able to take advantage of this development. This article proposes a novel framework in addressing the emerging need for interactivity while preserving and extending existing electronic medical data. The framework has 3 dimensions of patient health record: personal, social, and medical dimensions. The framework is designed to empower patients, changing their roles from static recipient of health care services to dynamic and active partners in health care processes.

  19. Nanotechnology in paper electronics

    Science.gov (United States)

    Demming, Anna; Österbacka, Professor Ronald; Han, Jin-Woo, Dr

    2014-03-01

    The ability to put cutting edge technology on paper—not in words but in a working physical form—has been attracting an increasing number of researchers over the past decade. Paper has many advantages that make it attractive for flexible electronics: it is relatively environmentally benign; it is renewable; it can be recycled; it is light weight; production processes for paper are well advanced; and it is inexpensive. This special issue, with guest editors Ronald Österbacka from Åbo Akademi University in Finland and Jin-Woo Han from the NASA AMES Research Center, features some of the latest in paper electronics research, including developments towards applications in displays, sensing and alternative energy sources, as well as fundamental studies to further our understanding of how paper can be most effectively used in electronics. As Andrew Steckl and colleagues in the US point out, 'Cellulose-based paper substrates were implemented as an electronic substrate as early as 1969, with most advancement occurring in the past decade largely due to technology improvements in thin film deposition and organic materials' [1, 2]. They report a detailed comparison between paper, standard liquid crystal display rigid glass and flexible glass for hosting pentacene organic thin film transistors, and obtain promising results for future paper-based devices. As most meaningful electronic devices rely on transistors to function, transistors feature quite prominently in this special issue. Rodrigo Martins and colleagues in France and Portugal study the effect of fibre type, structure and dimension on paper-based transistors and reveal further insights into how paper properties affect device performance [3]. Qing Wan and colleagues in China bring the state of the art in transistor technology to paper substrates [4], fabricating indium-zinc-oxide (IZO)-based protonic/electronic hybrid thin film transistors on paper and showing that they can be used as artificial synapses. Like the

  20. Electron acoustic solitary waves with kappa-distributed electrons

    Energy Technology Data Exchange (ETDEWEB)

    Devanandhan, S; Singh, S V; Lakhina, G S, E-mail: satyavir@iigs.iigm.res.in [Indian Institute of Geomagnetism, New Panvel (West), Navi Mumbai (India)

    2011-08-01

    Electron acoustic solitary waves are studied in a three-component, unmagnetized plasma composed of hot electrons, fluid cold electrons and ions having finite temperatures. Hot electrons are assumed to have kappa distribution. The Sagdeev pseudo-potential technique is used to study the arbitrary amplitude electron-acoustic solitary waves. It is found that inclusion of cold electron temperature shrinks the existence regime of the solitons, and soliton electric field amplitude decreases with an increase in cold electron temperature. A decrease in spectral index, {kappa}, i.e. an increase in the superthermal component of hot electrons, leads to a decrease in soliton electric field amplitude as well as the soliton velocity range. The soliton solutions do not exist beyond T{sub c}/T{sub h}>0.13 for {kappa}=3.0 and Mach number M=0.9 for the dayside auroral region parameters.